biology

Review Histone Deacetylase Inhibitors from Marine Invertebrates

Claudio Luparello * , Manuela Mauro, Vincenzo Arizza and Mirella Vazzana

Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy; [email protected] (M.M.); [email protected] (V.A.); [email protected] (M.V.) * Correspondence: [email protected]; Tel.: +39-91-238-97405



Received: 15 October 2020; Accepted: 25 November 2020; Published: 28 November 2020


Simple Summary: Histone deacetylases (HDACs) are enzymes that control gene expression and are involved in the onset of serious human pathologies, including cancer; hence, their inhibitors (HDACis) have received increased attention in recent years. It is known that marine invertebrates produce significant amounts of molecules showing active pharmacological properties and an extensive spectrum of biomedical applications. This review is focused on the description of the molecular, biochemical, and, where available, physiological aspects of marine invertebrate-derived compounds that possess HDACi properties, taking into consideration their possible utilization as treatment agents against different pathological states.

Abstract: Histone deacetylases (HDACs) are key components of the epigenetic machinery controlling gene expression. They are involved in chromatin remodeling events via post-translational histone modifications but may also act on nonhistone proteins, influencing many fundamental cellular processes. Due to the key involvement of HDACs in serious human pathologies, including cancer, HDAC inhibitors (HDACis) have received increased attention in recent years. It is known that marine invertebrates produce significant amounts of secondary metabolites showing active pharmacological properties and an extensive spectrum of biomedical applications. The aim of this review is to gather selected studies that report the extraction and identification of marine invertebrate-derived compounds that possess HDACi properties, grouping the producing species according to their taxonomic hierarchy. The molecular, biochemical, and/or physiological aspects, where available, and modes of action of these naturally occurring HDACis will be recapitulated, taking into consideration their possible utilization for the future design of analogs with increased bioavailability and efficacy, less toxicity, and, also, higher isoform selectivity.

Keywords: histone deacetylase inhibitors; marine invertebrates; anticancer compounds; biomedical applications; Porifera; Cnidaria; Echinodermata

1. A Brief Insight into Histone Deacetylases and Histone Deacetylase Inhibitors Histones are a group of proteins capable of interacting with DNA, thus forming the characteristic nucleosomal architecture of eukaryotic chromatin. Almost every biological process occurring in the nucleus, such as gene regulation, chromosome segregation, DNA replication, and repair, implies the subtle and precisely regulated adjustments of chromatin organization. Histone deacetylases (HDACs) are a key group of enzymes, highly conserved throughout evolution, involved in chromatin remodeling events via post-translational histone modification by catalyzing the removal of acetyl groups from lysine residues in their amino termini, thus determining chromatin condensation and transcriptional repression. These enzymes ay also act on non-histone proteins, thereby influencing

Biology 2020, 9, 429; doi:10.3390/biology9120429 www.mdpi.com/journal/biology Biology 2020, 9, 429 2 of 24 many fundamental cellular processes, including microtubule dynamics and intracellular transport, metabolism, and aging [1]. Eighteen HDACs have been identified in humans and subdivided taxonomically into four classes, as extensively reviewed by [2,3]: Class I (HDAC1, -2, -3, and -8), whose members are expressed ubiquitously, localized into the nucleus, and involved in the control of cell viability and proliferation; Class IIa (HDAC4, -5, -7, and -9) and IIb (HDAC6 and -10), whose members mostly show a tissue-specific expression profile and shuttle between the nucleus and the cytosol, with IIb enzymes controlling endothelial cell angiogenesis, cell proliferation, and migration, and T(reg) cell development and function; Class III, including nuclear sirtuin (SIRT)1, -6, and -7, the mitochondrial SIRT3 and -4, and the cytosolic SIRT2 and -5, involved in diverse activities such as the deacetylation of transcription factors and β-catenin and the regulation of metabolism and the oxidative stress response; and Class IV (HDAC11), often regarded as a hybrid of class I and II enzymes, shown to play a key role in the control of metabolism and obesity, the development of oligodendrocytes, and the functioning of the immune system. The HDACs belonging to classes I, IIa, IIb, and IV are Zn++-dependent enzymes, whereas SIRTs require NAD+ for catalysis. The manifold regulatory roles played by HDACs account for their key importance in serious human pathologies, including cancer. Taking the aberrant gene expressions occurring in oncodevelopment into account, the involvement of HDACs is unsurprising and, also, on the basis of the known association of the enzymes with a number of well-characterized cellular oncogenes and oncosuppressor genes (e.g., Rb and p53), thereby altering the physiologic gene expression pattern and leading to cell hyperproliferation, invasion, and metastasis [4,5]. Histone deacetylase inhibitors (HDACis) belong to a large group of chemically different compounds, which includes complex molecules such as hydroxamates, cyclic tetrapeptides/epoxides, and benzamides, and relatively simple short-chain aliphatic acids, such as valproic acid and butyric acid [6–11]. This chemical heterogeneity implies a difference in the precise molecular mechanism of action that, for several members, is still poorly understood and, also, given that eighteen diverse HDACs exist in mammalian cells, with differing intracellular localizations, interactions with other proteins, and associations in multimolecular complexes. HDACis are well-known antineoplastic compounds, the most potent to date being trichostatin A, active in vitro at nanomolar concentrations, which is a fermentation product of Streptomyces bacteria originally utilized as an antimycotic agent and later found to restrain the proliferation of cultured tumor cells [12]. The need for alternative HDACis, due to the difficulties and costs related to trichostatin A production, determined the introduction of a number of other inhibitors, such as butyrate, phenylbutyrate, depsipeptide, pyroxamide, suberoylanilide bishydroxyamide, valproic acid, and N-acetyldinaline in the clinical trials for anticancer activity, thus expanding the opportunities for epigenetic therapies [13]. In addition to the antineoplastic mechanism based upon reprogramming of the gene expression that ultimately suppresses cell proliferation and motility, HDACis have been proven to promote tumor cell death via apoptosis in a more powerful way when used in combination with other agents, e.g., [14], and, also, to inhibit endothelial cell growth and tumor angiogenesis [15,16]. Noteworthy, further applications of these compounds currently under study include the treatment of fungal infections and human neurological pathologies, such as Rett syndrome, Friedrich’s ataxia, Huntington’s chorea, and spinal muscular atrophy [17–21]. Seas and oceans, which cover three-quarters of the globe, host an enormous diversity of organisms, many of which are still unknown, and represent the underexploited richest source of bioactive marine natural products. Invertebrates, which account for more than 50% of the species colonizing the aquatic environment in Europe, are important environmental bioindicators [22–25]. They are known to produce significant amounts of secondary metabolites with unique chemical skeletons as molecular cues addressed to regulate very disparate biological activities, e.g., feeding; inter- and intraspecific Biology 2020, 9, 429 3 of 24

Biology 2020, 9, x 3 of 26 signalizations; mating; predation; and defense from predators, competitors, pathogenic microorganisms, andmechanisms UV radiation to the damage. specific These life conditions products contribute in the greatly to the different adaptation marine mechanisms ecosystems to the [26]. specific A large life conditionsproportion inof the greatlyinvertebrate-derived different marine extracts ecosystems and [26 isolated]. A large proportioncompounds of invertebrate-derivedhas shown active extractspharmacological and isolated properties, compounds such as has anticancer, shown active antimicrobial, pharmacological and anti-inflammatory, properties, such among as anticancer, others, antimicrobial,with an extensive and spectrum anti-inflammatory, of biomedical among appl others,ications with that an makes extensive them spectrum already ofapproved biomedical or applicationsprospective drugs that makes of marine them origin already with approved promising or prospective results for different drugs of therapeutic marine origin purposes with promising [27–32]. resultsWithin forthis di scenario,fferent therapeutic the aim of purposes this review [27– 32is ].to Withingather thisselected scenario, studies the aimthat of reported this review the isextraction to gather selectedand identification studies that of reported marine the invertebrate-derived extraction and identification chemicals of marinethat possess invertebrate-derived HDACi properties chemicals and thatrecapitulate possess the HDACi molecular, properties biochemical, and recapitulate and/or physiological the molecular, aspects, biochemical, where andavailable,/or physiological which are aspects,associated where with available,the examined which molecules. are associated In particul with thear, a examined focus will molecules. be put on Inthe particular, gene expression a focus willsignatures be put associated on the gene with expression the exposure signatures of different associated tumoral withcytotypes the exposure to the distinct of di ffHDACis,erent tumoral when cytotypesinformation to is the available. distinct The HDACis, matter when of this information review will is be available. dealt with The according matter of to this the review taxonomic will behierarchy dealt with of the according producing to invertebrate the taxonomic species, hierarchy and the ofthe structural/zoological producing invertebrate aspects species, of each andtype the of structuralorganism /willzoological also be aspects briefly ofdiscussed. each type of organism will also be briefly discussed. 2. Porifera 2. Porifera Porifera is the oldest still-existing metazoan group, which comprises sponges, sessile aquatic Porifera is the oldest still-existing metazoan group, which comprises sponges, sessile aquatic organisms endowed with a very simple pattern of body organization constituted by a skin covering organisms endowed with a very simple pattern of body organization constituted by a skin covering a collagenous matrix crossed by canals and microscopic chambers. A comprehensive picture of the a collagenous matrix crossed by canals and microscopic chambers. A comprehensive picture of the global biodiversity of this phylum can now be obtained through the online World Porifera Database, global biodiversity of this phylum can now be obtained through the online World Porifera Database, which gathers all the taxonomic and distribution data of the species known so far [33]. which gathers all the taxonomic and distribution data of the species known so far [33]. 2.1. Psammaplins 2.1. Psammaplins Aplysinella rhax (Laubenfels, 1954; Demospongiae, Verongiida: Aplysinellidae), originally Aplysinella rhax (Laubenfels, 1954; Demospongiae, Verongiida: Aplysinellidae), originally described as Dysidea rhax [34], is a demosponge commonly distributed in the Pacific Ocean that described as Dysidea rhax [34], is a demosponge commonly distributed in the Pacific Ocean that presents dendritic fibers with upright fleshy bulbs and an opaque, membranous, and optically smooth presents dendritic fibers with upright fleshy bulbs and an opaque, membranous, and optically surface ornamentation overlying small clumps of fibers and forming an irregular and bumpy surface smooth surface ornamentation overlying small clumps of fibers and forming an irregular and bumpy (Figure1). surface (Figure 1).

Figure 1. Specimens of Aplysinella rhax demosponge (CC BY 3.0 AU). https://bie.ala.org.au/species/urn: Figure 1. Specimens of Aplysinella rhax demosponge (CC BY 3.0 AU). lsid:biodiversity.org.au:afd.taxon:e5607759-f60b-453a-b37a-30f3726d03c2#gallery. https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:e5607759-f60b-453a-b37a- 30f3726d03c2#gallery. Psammaplysilla purpurea, currently Pseudoceratina purpurea (Carter, 1880; Demospongiae, Verongiida: Pseudoceratinidae), is a subtropical, sessile, filter-feeder, and hermaphroditic demosponge populating Psammaplysilla purpurea, currently Pseudoceratina purpurea (Carter, 1880; Demospongiae, the boulders and rock slabs in the lower eulittoral subzone of the Indian Ocean and the coasts of Verongiida: Pseudoceratinidae), is a subtropical, sessile, filter-feeder, and hermaphroditic demosponge populating the boulders and rock slabs in the lower eulittoral subzone of the Indian Ocean and the coasts of Madagascar, Saudi Arabia, and India. Its body consists of poorly developed

Biology 2020, 9, 429 4 of 24

Biology 2020, 9, x 4 of 26 Biology 2020, 9, x 4 of 26 Madagascar, Saudi Arabia, and India. Its body consists of poorly developed spongin fibers with a spongin fibers with a collagenous choanosome, being irregularly spherical with an uneven surface spongincollagenous fibers choanosome, with a collagenous being irregularly choanosome, spherical being withirregularly an uneven spherical surface with that an houses uneven scattered, surface that houses scattered, small, and sharp conules and prominent oscula (Figure 2) [35,36]. thatsmall, houses and sharp scattered, conules small, and and prominent sharp conules oscula and (Figure prominent2)[35,36 oscula]. (Figure 2) [35,36].

Figure 2. SpecimenSpecimen of Pseudoceratina purpurea demosponge [37]. [37]. Figure 2. Specimen of Pseudoceratina purpurea demosponge [37]. Dendrilla lacunosa, currently Ernstilla lacunosa (Hentschel, 1912; Demospongiae, Dendroceratida: Dendrilla lacunosa, currently Ernstilla lacunosa (Hentschel, 1912; Demospongiae, Dendroceratida: Darwinellidae), was first described in Indonesia in 1912 and, 100 years later, found also in Western Darwinellidae), was first described in Indonesia in 1912 and, 100 years later, found also in Western Australia and updated. This organism shows a typical aqua blue color and long structures reminescent Australia and updated. This organism shows a typical aqua blue color and long structures of whips (Figure3)[38]. reminescent of whips (Figure 3) [38].

Figure 3. Specimens of Dendrilla lacunosa demosponge [38]. [38]. Figure 3. Specimens of Dendrilla lacunosa demosponge [38]. The species of the genus Jaspis (Demospongiae, Tetractinellida: Ancorinidae) comprise benthonic The species of the genus Jaspis (Demospongiae, Tetractinellida: Ancorinidae) comprise and suspension-The species orof filter-feederthe genus organismsJaspis (Demospongiae, typical of intertidal Tetractinellid environments.a: Ancorinidae) Depending comprise on the benthonic and suspension- or filter-feeder organisms typical of intertidal environments. Depending benthonicspecies, these and spongessuspension- can haveor filter-feeder a wide distribution organisms throughouttypical of intertidal Kenya, Sudan,environments. Madagascar, Depending South on the species, these sponges can have a wide distribution throughout Kenya, Sudan, Madagascar, onKorea, the Australia,species, these the Atlanticsponges Ocean, can have and a the wide Mediterranean distribution Sea.throughout In most cases,Kenya, they Sudan, display Madagascar, a massive South Korea, Australia, the Atlantic Ocean, and the Mediterranean Sea. In most cases, they display a Southspheroidal Korea, morphology, Australia, the but, Atlantic also, tubular Ocean, or and calyx the structuresMediterranean are documented. Sea. In most Thesecases, they organisms display are a massive spheroidal morphology, but, also, tubular or calyx structures are documented. These massiveendowed spheroidal with siliceous morphology, four-rayed but, spicules also, or,tubu sometimes,lar or calyx with structures desmas without are documented. spicules and These often organisms are endowed with siliceous four-rayed spicules or, sometimes, with desmas without organismsshow a very are robust endowed and strongly with siliceous colored peripheralfour-rayed ectosomalspicules or, layer sometimes, (Figure4)[ with39,40 ].desmas without spicules and often show a very robust and strongly colored peripheral ectosomal layer (Figure 4) [39,40].

Biology 2020, 9, x 5 of 26 Biology 2020, 9, 429 5 of 24 Biology 2020, 9, x 5 of 26

Figure 4. Two examples of species of the genus Jaspis. (A) Jaspis coriacea (Carter, 1886) and (B) Jaspis splendens (de Laubenfels, 1954) [41]. FigureFigure 4.4. Two examplesexamples ofof speciesspecies ofof thethe genusgenus Jaspis.Jaspis. ((A)) JaspisJaspis coriaceacoriacea (Carter,(Carter, 1886)1886) andand ((BB)) JaspisJaspis splendens (de Laubenfels, 1954) [41]. Poecillastrasplendens (de wondoensis Laubenfels, (Sim 1954) and[41]. Kim, 1995; Demospongiae, Tetractinellida: Vulcanellidae) is a demospongePoecillastra distributed wondoensis in (SimKorea, and showing Kim, 1995; long Demospongiae,oxeas with triaenes Tetractinellida: that include Vulcanellidae)protriaenes longer is a Poecillastra wondoensis (Sim and Kim, 1995; Demospongiae, Tetractinellida: Vulcanellidae) is a thandemosponge 2000 µm distributed[42]. in Korea, showing long oxeas with triaenes that include protriaenes longer demosponge distributed in Korea, showing long oxeas with triaenes that include protriaenes longer thanThe 2000 Poriferaµm [42]. listed above have been proven to be good producers of psammaplins, a family of than 2000 µm [42]. phenolicThe compounds Porifera listed whose above HDAC have beeninhibitory proven activi to bety goodhas been producers shown of by psammaplins, experimental a assays family on of The Porifera listed above have been proven to be good producers of psammaplins, a family of differentphenolic compoundsmodel systems whose in vitro. HDAC The inhibitory first member activity isolated has been wasshown the brominated by experimental tyrosine-derived assays on phenolic compounds whose HDAC inhibitory activity has been shown by experimental assays on psammaplindifferent model A (Figure systems 5A),in vitro initially. The described first member as an isolated antimicrobial was the brominatedand antifungal tyrosine-derived agent acting different model systems in vitro. The first member isolated was the brominated tyrosine-derived throughpsammaplin the impairment A (Figure5A), ofinitially DNA synthesis described and as anchitinase antimicrobial enzymatic and antifungalactivity and agent then acting revealed through as a psammaplin A (Figure 5A), initially described as an antimicrobial and antifungal agent acting HDACithe impairment acting via of the DNA coordination synthesis andof a chitinasezinc ion in enzymatic the catalytic activity pocket and of then HDAC, revealed with a as sulfhydryl a HDACi through the impairment of DNA synthesis and chitinase enzymatic activity and then revealed as a groupacting viaactivated the coordination by a reducing of a zincagent ion [43–46]. in the catalytic Other members pocket of of HDAC, the ps withammaplin a sulfhydryl group, group i.e., HDACi acting via the coordination of a zinc ion in the catalytic pocket of HDAC, with a sulfhydryl psammaplinactivated by aB–J reducing and agentbisaprasin, [43–46 ].were Other subsequently members of the isolated psammaplin and group,characterized, i.e., psammaplin but only B–J group activated by a reducing agent [43–46]. Other members of the psammaplin group, i.e., psammaplinsand bisaprasin, A wereand F, subsequently the latter differing isolated for and a C2 characterized,H2NO3 terminal but group, only psammaplinsa carboxylic acid A andmoiety, F, the a psammaplin B–J and bisaprasin, were subsequently isolated and characterized, but only secondarylatter differing amide for functional a C2H2NO group,3 terminal and group,an N-substituted a carboxylic oxalamic acid moiety, acid group, a secondary and bisaprasin amide functional (Figure psammaplins A and F, the latter differing for a C2H2NO3 terminal group, a carboxylic acid moiety, a 5B)group, were and proven an N -substitutedto have HDACi oxalamic properties acid group,when incubated and bisaprasin with the (Figure 3H-acetylated5B) were provenhuman tohistone have secondary amide functional group, and an N-substituted oxalamic acid group, and bisaprasin (Figure H4HDACi peptide properties substrate when [44,47]. incubated In the with following the 3H-acetylated lines, the humaneffects histoneof psammaplins H4 peptide on substrate neoplastic [44 ,cell47]. 5B) were proven to have HDACi properties when incubated with the 3H-acetylated human histone modelIn the followingsystems are lines, recapitulated. the effects of psammaplins on neoplastic cell model systems are recapitulated. H4 peptide substrate [44,47]. In the following lines, the effects of psammaplins on neoplastic cell model systems are recapitulated.

Figure 5. (A) Structures of psammaplin A (A) and bisaprasin (B). Figure 5. (A) Structures of psammaplin A (A) and bisaprasin (B). Psammaplins and breast cancer cells: In light of molecular modeling data identifying several potential-binding sites for psammaplin A within the peroxisome proliferator-activated receptor γ Psammaplins andFigure breast 5. (Acancer) Structures cells: ofIn psammaplin light of molecular A (A) and modeling bisaprasin data (B). identifying several (PPARγ) ligand-binding pocket, Mora et al. [48] demonstrated the psammaplin-induced activation potential-binding sites for psammaplin A within the peroxisome proliferator-activated receptor γ of thePsammaplins receptor in aand MCF-7 breast breast cancer tumor cells: cell-based In light of reporter molecular assay, modeling followed data by identifying the promotion several of (PPARγ) ligand-binding pocket, Mora et al. [48] demonstrated the psammaplin-induced activation apoptoticpotential-binding death at sites least for in partpsammaplin mediated A by within the switch-on the peroxisome of the PPAR proliferator-activatedγ-regulated gene expression.receptor γ of the receptor in a MCF-7 breast tumor cell-based reporter assay, followed by the promotion of In(PPAR 2012,γ Baud) ligand et al.-binding [49] demonstrated pocket, Mora the HDACet al. [48] isoform demonstrated selectivity the of psammaplin-induced psammaplin A, which activation appeared apoptotic death at least in part mediated by the switch-on of the PPARγ-regulated gene expression. of the receptor in a MCF-7 breast tumor cell-based reporter assay, followed by the promotion of apoptotic death at least in part mediated by the switch-on of the PPARγ-regulated gene expression.

Biology 2020, 9, x 6 of 26

In 2012, Baud et al. [49] demonstrated the HDAC isoform selectivity of psammaplin A, which appeared to be 360-fold selective for HDAC1 over HDAC6 and more than 1000-fold less powerful towards HDAC7 and HDAC8, being the same selectivity profile maintained in MCF-7 cells as an in vitro model system. More recently, Zhou et al. [50] exposed both the estrogen-dependent T47D cells and different genetically characterized metastatic subclones of triple-negative MDA-MB231 cells specificBiology to lung,2020, 9, 429bone, and brain to different psammaplins. They found a powerful inhibitory6 of 24 activity of the proliferation and three-dimensional invasive growth of tumor cells, except for the brain metastatic subclone, by the stereo isomers (e,z)-psammaplin A and (e,e)-psammaplin A compared to to be 360-fold selective for HDAC1 over HDAC6 and more than 1000-fold less powerful towards bisaprasinHDAC7 and and psammaplins HDAC8, being theE and same K. selectivity From a profilemolecu maintainedlar point in of MCF-7 view, cells psammaplin as an in vitro Amodel was proven to triggersystem. the activity More recently, of the Zhou hypoxia-inducible et al. [50] exposed bothfactor the (HIF) estrogen-dependent and the upregulation T47D cells and of diHIFfferent target genes, such asgenetically cyclin-dependent characterized kinase metastatic inhibitor subclones 1A of ( triple-negativeCDKN1A) and MDA-MB231 vascular endothelial cells specific to growth lung, factor A (VEGFAbone,; this and only brain toby di thefferent e,e psammaplins. isomer) and They the found downregulation a powerful inhibitory of sirtuin-1 activity of(SIRT1) the proliferation, the latter leading to theand increased three-dimensional p53 acetylation invasive growth and of tumorautophagy-related cells, except for the gene brain metastaticexpression subclone, and, by ultimately, the to stereo isomers (e,z)-psammaplin A and (e,e)-psammaplin A compared to bisaprasin and psammaplins autophagicE and K.cell From death. a molecular point of view, psammaplin A was proven to trigger the activity of the Psammaplinhypoxia-inducible A and factor endometrial (HIF) and the cancer upregulation cells: Ahn of HIF et target al. [51] genes, reported such as the cyclin-dependent inhibitory effect of the compoundkinase inhibitoron Ishikawa 1A (CDKN1A endometrial) and vascular cancer endothelial cells via growthcell cycle factor arrest A (VEGFA at the; this G1 only and by G the2/Me, ephases and apoptosisisomer) promotion. and the downregulation Molecular of events sirtuin-1 associated (SIRT1), the latterwith leading the im topairment the increased of p53 the acetylation cell cycle and the inductionand autophagy-related of apoptosis were gene the expression downregulation and, ultimately, of tocyclin autophagic D1, cyclin cell death. E, and CDK4 (involved in the Psammaplin A and endometrial cancer cells: Ahn et al. [51] reported the inhibitory effect of block of G1 phase progression); cyclin A, cyclin B1, and CDK2 (involved in the block of G2/M phase the compound on Ishikawa endometrial cancer cells via cell cycle arrest at the G1 and G2/M phases progression);and apoptosis and promotion. the upregulation Molecular events of associatedp21WAF1, withalong the impairmentwith a ofdecrease the cell cyclein andthe level of hyperphosphorylatedthe induction of apoptosis pRb. were the downregulation of cyclin D1, cyclin E, and CDK4 (involved Psammaplinin the block of A G and1 phase C and progression); glioblastoma cyclin cells: A, cyclin psammaplin B1, and CDK2 C (Figure (involved 6) is in a thepowerful block of inhibitor of WAF1 carbonicG2/M anhydrase phase progression); XII [52], and thewhose upregulation activity of p21is required, along withto aensure decrease an in theefficient level of efflux of hyperphosphorylated pRb. chemotherapeuticsPsammaplin by A anda P-glycoprotein C and glioblastoma pump cells: psammaplinin tumor Ccells. (Figure Salaroglio6) is a powerful et al. inhibitor [53] reported of that carboniccarbonic anhydrase anhydrase XII XII [52is ],overexpressed whose activity is required in glio toblastoma ensure an effistemcient ecellsfflux ofand chemotherapeutics that a combination of psammaplinby a P-glycoprotein C and temozolomide, pump in tumor the cells. latter Salaroglio being et th al.e [ 53first-line] reported drug that carbonicin glioblastoma anhydrase treatment, rescuesXII its is overexpressedefficacy against in glioblastoma the highly stem chemorefra cells andctory that a stem combination component of psammaplin of the glioblastoma C and cell population.temozolomide, More therecent latter data being the[54] first-line demonstrated drug in glioblastoma an even treatment,greater rescuesefficacy, its einffi cacythe order of against the highly chemorefractory stem component of the glioblastoma cell population. More recent subnanomolardata [54] demonstrated carbonic anhydrase an even greater XII inhibitory efficacy, in theacti ordervity, ofby subnanomolar a variant of the carbonic molecule anhydrase endowed with a thiadiazoleXII inhibitory sulfonamide activity, by moiety a variant replacing of the molecule the ethyl endowed sulfonamide with a thiadiazole one, which sulfonamide was able moiety to inhibit also carbonicreplacing anhydrase the ethyl IX, sulfonamide the other one,cancer-associated which was able to isozyme. inhibit also carbonic anhydrase IX, the other cancer-associated isozyme.

Figure 6. Structure of psammaplin C.

Figure 6. Structure of psammaplin C.

Biology 2020, 9, x 7 of 26

Dealing with psammaplin A, a molecular study performed by Ratovitski [55] on U87-MG glioblastomaBiology cells2020, 9 , 429demonstrated the ability of the compound to induce the expression7 of 24 and phosphorylation of TP53 family members instrumental for the transcriptional activation of downstream targetDealing genes with psammaplinsuch as those A, ainvolved molecular in study autophagy performed signaling, by Ratovitski i.e., [ATG555] on U87-MGcoding for the Autophagy-Relatedglioblastoma 5 cells protein demonstrated and UVRAG the ability coding of the for compound the UV toRadiation induce the Resistance-Associated expression and protein. Confirmationphosphorylation of of TP53the autophagy family members flux-promoti instrumentalng for activity the transcriptional was obtained activation by of an downstream electrophoretic target genes such as those involved in autophagy signaling, i.e., ATG5 coding for the Autophagy-Related analysis of the LC3B-I/LC3B-II shift. 5 protein and UVRAG coding for the UV Radiation Resistance-Associated protein. Confirmation It mustof thebe autophagymentioned flux-promoting that a number activity of experime was obtainedntal investigations, by an electrophoretic such as analysis that of of Mujumdar the et al. [52]LC3B-I referenced/LC3B-II above, shift. have been focused on the synthesis and characterization of a series of psammaplin derivativesIt must be mentionedthat might thatshow a a number greater of HDAC experimental inhibitory investigations, efficacy and such cytotoxic as that potential, of although Mujumdarthey provided et al. [52mixed] referenced results. above, Among have the been most focused successful on the synthesis ones, the and studies characterization of Baud et al. of a series of psammaplin derivatives that might show a greater HDAC inhibitory efficacy and cytotoxic [49] demonstrated the particularly potent activity of the (2E,2′E)-N,N′-(2,2′-Disulfanediylbis (ethane- potential, although they provided mixed results. Among the most successful ones, the studies of 2,1-diyl))bis(3-(3-bromo-4-methoxyphenyl)-2-(hydroxyimino)propanamide) variant towards MCF-7 Baud et al. [49] demonstrated the particularly potent activity of the (2E,20E)-N,N0-(2,20-Disulfanediylbis breast cancer(ethane-2,1-diyl))bis(3-(3-bromo-4-methoxyphenyl)-2-(hydroxyimino)propanamide) and A549 lung cancer cells. In addition, Byun et al. [56] reported the variant significant towards in vitro and in vivoMCF-7 anti-breast breast cancer tumor and A549 and lung antimetastatic cancer cells. In addition,activity Byunof psammaplin et al. [56] reported A-3091 the significant (Figure 7), a heteromonomeric-structuredin vitro and in vivo anti-breast analog tumor with anda tertiary antimetastatic butyl activityfunctional of psammaplin group able A-3091 to specifically (Figure7), target a heteromonomeric-structured analog with a tertiary butyl functional group able to specifically target DOT1L, coding for the disruptor of Telomeric silencing 1-like protein, involved in the regulation of DOT1L, coding for the disruptor of Telomeric silencing 1-like protein, involved in the regulation of both the epithelial-mesenchymalboth the epithelial-mesenchymal transition transition and and the the stem stem cellcell properties properties of breastof breast cancer cancer cells. cells.

Figure 7. Structure of psammaplin A-3091 [56]. 2.2. Yakushinamides Figure 7. Structure of psammaplin A-3091 [56]. Theonella swinhoei (Gray, 1868; Demospongiae, Tetractinellida: Theonellidae, Figure8) is a sessile, 2.2. Yakushinamideshermaphrodite, and filter-feeder species typical of the Indo-West Pacific area, where it populates the tropical environments in a depth range between 20 and 188 m. Its covering dimensions range from Theonella2.0 to 200swinhoei mm, and (Gray, it is regarded 1868; asDemospongiae, a remarkable component Tetractinellida: of the sponge Theonellidae, population in coralFigure reef 8) is a sessile, hermaphrodite,communities, much and studied filter-feeder because it represents species atypical suitable microenvironmentof the Indo-West for thePacific development area, ofwhere it populatesdi thefferent tropical types ofenvironments autotrophic and in heterotrophic a depth range organisms between that inhabit20 and di 188fferent m. partsIts covering of its body dimensions [57]. range from 2.0 to 200 mm, and it is regarded as a remarkable component of the sponge population in coral reef communities, much studied because it represents a suitable microenvironment for the development of different types of autotrophic and heterotrophic organisms that inhabit different parts of its body [57].

Biology 2020, 9, 429 8 of 24 Biology 2020, 9, x 8 of 26 Biology 2020, 9, x 8 of 26

Figure 8. Image of a colony of Theonella swinhoei demosponges; http://www.marinespecies. FigureFigure 8.8.Image Image of aof colony a colony of Theonella of Theonella swinhoei swinhoeidemosponges; demosponges; http://www.marinespecies.org http://www.marinespecies./aphia. org/aphia.php?p=image&tid=171264&pic=133237. Licensed under a Creative Commons Attribution- php?porg/aphia.php?p=image&tid=171264&=image&tid=171264&pic=133237pic=133237.. Licensed under Licensed a Creative under Commonsa Creative Attribution-Commons Attribution- Share Alike Share Alike 3.0 License. 3.0Share License. Alike 3.0 License. From this demosponge, Takada et al. [58] isolated two prolyl amides of polyoxygenated fatty FromFrom thisthis demosponge,demosponge, Takada Takada et et al. al. [58 [58]] isolated isolated two two prolyl prolyl amides amides of polyoxygenated of polyoxygenated fatty fatty acid, acid, i.e., yakushinamide A (Figure 9), which displayed a moderate inhibitory effect on HDACs and i.e.,acid, yakushinamide i.e., yakushinamide A (Figure A (Figure9), which 9), displayedwhich displayed a moderate a moderate inhibitory inhibitory e ffect on effect HDACs on HDACs and sirtuins. and sirtuins. In particular, yakushinamide A inhibited HDAC1, SIRT1, and -3 at 26, 16, and 79 µM, Insirtuins. particular, In particular, yakushinamide yakushinamide A inhibited A HDAC1,inhibited SIRT1,HDAC1, and SIRT1, -3 at 26, and 16, -3 and at 7926,µ 16,M, respectively,and 79 µM, respectively, whereas yakushinamide B at 29, 75, 52, 34, 150, and 78 µM, respectively. whereasrespectively, yakushinamide whereas yakushinamide B at 29, 75, 52, B 34, at 150,29, 75, and 52, 78 34,µM, 150, respectively. and 78 µM, respectively.

Figure 9. Structures of yakushinamide (A) and (B). Figure 9. Structures of yakushinamide (A) and (B). The species of the genusFigureHalichondria 9. Structures(Fleming, of yakushinamide 1828; Demospongiae, (A) and (B). Suberitida: Halichondriidae, FigureThe 10) arespecies massive of and the amorphous genus Halichondria sponges typical (Fleming, of rocky substrates1828; Demospongiae, and with a cosmopolitan Suberitida: The species of the genus Halichondria (Fleming, 1828; Demospongiae, Suberitida: distribution.Halichondriidae, These Figure organisms 10) are are massive filter-feeders, and amorphous and some sponges species oftypical this genus of rocky can substrates often develop and with on Halichondriidae, Figure 10) are massive and amorphous sponges typical of rocky substrates and with thea cosmopolitan carapace of crabs distribution. or on the These shells organisms of mollusks. are filter-feeders, Their internal and and some external species skeletons of this consistgenus can of a cosmopolitan distribution. These organisms are filter-feeders, and some species of this genus can bundlesoften develop of spicules on arrangedthe carapace randomly. of crabs They or canon the have shells a granular, of mollusks. smooth, Their or glassy internal shape, and and external their often develop on the carapace of crabs or on the shells of mollusks. Their internal and external colorsskeletons can varyconsist according of bundles to the of depthspicules of arranged the waters randomly. in which theyTheyare can located, have a beinggranular, white-grey smooth, in or skeletons consist of bundles of spicules arranged randomly. They can have a granular, smooth, or deepglassy and shape, greener and in their shallow colors waters can vary thanks according to the to presence the depth of of light the thatwaters allows in which the development they are located, of glassy shape, and their colors can vary according to the depth of the waters in which they are located, symbioticbeing white-grey algae in thein deep latter and case greener [59]. in shallow waters thanks to the presence of light that allows being white-grey in deep and greener in shallow waters thanks to the presence of light that allows the development of symbiotic algae in the latter case [59]. the development of symbiotic algae in the latter case [59].

Biology 2020, 9, x 9 of 26 Biology 2020, 9, 429 9 of 24 Biology 2020, 9, x 9 of 26

Figure 10. Two examples of species of the genus Halichondria. (A) Halichondria panicea (Pallas, 1766), taken from [60]. (B) Halichondria bowerbanki (Burton, 1930), taken from [61]. Figure 10. Two examples of species of the genus Halichondria..( (A)) Halichondria panicea panicea (Pallas,(Pallas, 1766), 1766), taken2.3. Halistanol from [60]. [60]. (Sulphates (B)) HalichondriaHalichondria bowerbanki (Burton,(Burton, 1930), taken from [61]. [61]. 2.3. Halistanol Sulphates 2.3. HalistanolIn the Sulphates search for new SIRT inhibitors from marine sponges, from this species, Nakamura et al. [62] isolated the highly sulphated steroid halistanol sulphate (Figure 11) and two novel analogs, i.e., In the search for new SIRT inhibitors from marine sponges, from this species, Nakamura et al. [62] Inhalistanol the search sulphate for new I SIRTand -J,inhibitors differing from from marine the parental sponges, molecule from this for species, methylene Nakamura protons et al.and the isolated the highly sulphated steroid halistanol sulphate (Figure 11) and two novel analogs, i.e., [62] isolatedcyclopropyl the highly ring insulphated the side steroidchain, halistanolrespectively. sulphate When (Figuresubmitted 11) andto an two in vitronovel SIRT1-3 analogs, inhibitory i.e., halistanol sulphate I and -J, differing from the parental molecule for methylene protons and the halistanolassay, sulphate these compounds I and -J, differing were shown from to the be parentalactive, with molecule half maximal for methylene inhibitory protons concentration and the (IC50) cyclopropyl ring in the side chain, respectively. When submitted to an in vitro SIRT1-3 inhibitory cyclopropylvalues ringof 45.9–67.9, in the side 18.9–21.1, chain, respectively.and 21.8–37.5 When µM, respectively.submitted to Onan inthe vitro other SIRT1-3 hand, theyinhibitory exerted no assay, these compounds were shown to be active, with half maximal inhibitory concentration (IC50) assay,cytotoxic these compounds effects on were HeLa shown cervical to be active,adenocarci with nomahalf maximal and P388 inhibi mousetory concentration leukemia cells (IC 50at) the values of 45.9–67.9, 18.9–21.1, and 21.8–37.5 µM, respectively. On the other hand, they exerted no valuesconcentration of 45.9–67.9, of18.9–21.1, 100 µM. and Studies 21.8–37.5 on the µM, crystal respectively. structure Onof thethe SIRT3-halistanol other hand, they sulphate exerted complexno cytotoxic effects on HeLa cervical adenocarcinoma and P388 mouse leukemia cells at the concentration cytotoxicindicated effects the on existence HeLa cervicalof an allosteric adenocarci sitenoma for enzyme and P388 inhibition mouse far leukemia from the cells SIRT at active the site, of 100 µM. Studies on the crystal structure of the SIRT3-halistanol sulphate complex indicated the concentrationsubstrate-binding of 100 µM. site, Studies and NAD on the+ cofactor-binding crystal structure site, of the thus SIRT3-halistanol suggesting that sulphate steroid sulphatescomplex may existence of an allosteric site for enzyme inhibition far from the SIRT active site, substrate-binding site, indicatedbe endowed the existence with aof good an motifallosteric for thesite allosteric for enzyme regulation inhibition of enzymes. far from the SIRT active site, and NAD+ cofactor-binding site, thus suggesting that steroid sulphates may be endowed with a good substrate-binding site, and NAD+ cofactor-binding site, thus suggesting that steroid sulphates may motif for the allosteric regulation of enzymes. be endowed with a good motif for the allosteric regulation of enzymes.

Figure 11. Structure of halistanol sulphate. Figure 11. Structure of halistanol sulphate. 2.4. Azumamides The species of the genus MycaleFigure(Gray, 11. Structure 1867; Demospongiae, of halistanol sulphate. Poecilosclerida: Mycalidae; Figure 12) gather demosponges presenting smooth, subterminally constricted-style megascleres (“mycalostyles”) in combination with anisochelate microscleres [63].

Biology 2020, 9, x 10 of 26

2.4. Azumamides The species of the genus Mycale (Gray, 1867; Demospongiae, Poecilosclerida: Mycalidae; Figure Biology12) gather2020, 9, 429demosponges presenting smooth, subterminally constricted-style megascleres10 of 24 (“mycalostyles”) in combination with anisochelate microscleres [63].

Figure 12.12. TwoTwo examples examples of of species species of theof the genus genusMycale Mycale.(A). Mycale(A) Mycale laevis ,laevis (Carter,, (Carter, 1882); CC01882); 1.0 CC0 (Public 1.0 domain)(Public domain) https://serv.biokic.asu.edu https://serv.biokic.asu/imglib.edu/imglib/stri/misc/201605/13568_1464650224_web.jpg./stri/misc/201605/13568_1464650224_web.jpg.(B) Mycale (B) laxissimaMycale (Duchassainglaxissima and Michelotti,(Duchassaing 1864); https: //spongeguide.uncw.eduand Michelotti,/imageinfo.php?img 1864);=319. https://spongeguide.uncw.edu/imageinfo.php?img=319. Among these, the species Mycale izuensis (Tanita and Hoshino, 1989) populates the Pacific Ocean, beingAmong especially these, typical the species of Japan, Mycale and izuensis is characterized (Tanita and by Hoshino, clusters of 1989) digitations populates up the to 6-cm-high Pacific Ocean, and 1.5being cm especially in diameter typical rising of from Japan, a commonand is characteri base andzed bearing by clusters small of apical digita oscules.tions up Itsto 6-cm-high body contains and a1.5 skeleton cm in diameter of plumose rising spicule from a tracts common that base diverge and and bearing thin small out towards apical oscules. the periphery Its body [ 64contains]. From a thisskeleton marine of plumose organism, spicule Nakao tracts et al. that [65 ]diverge isolated and five thin cyclic out tetrapeptides towards the namedperiphery azumamides [64]. From A-Ethis endowedmarine organism, with HDACi Nakao activity et al. in enzymatic[65] isolated assays five (Figure cyclic 13 tetrapeptides). Azumamide named A was initiallyazumamides also tested A-E atendowed the cell level,with HDACi showing activity a moderate in enzymatic cytostatic assays effect on(Figure K562 13). cells Azumamide and a significant A was antiangiogenic initially also etestedffecton at mousethe cell vascular level, progenitorshowing a cells.moderate Subsequently, cytostatic a totaleffect synthesis on K562 was cells reported and a forsignificant the sole azumamidesantiangiogenic A andeffect E, on and mouse research vascular interest progen was mainlyitor cells. focused Subsequently, on the greater a total HDACi synthesis efficacy was of azumamidereported for E,the which sole azumamides appeared able A to and inhibit E, and total rese HDACsarch interest from HeLa was cellmainly extracts focused with on a much the greater lesser ICHDACi50 (110 efficacy33 nM) of azumamide with respect E, towhich that appeared of azumamide able to A inhibit (5800 total1200 HDACs nM) and from showed HeLa cell selectivity extracts ± ± forwith HDAC1-4. a much lesser In particular, IC50 (110 from± 33 nM) a biological with respect point to of that view, of theazumamide compound A proved(5800 ± to1200 be nM) a strong and inhibitorshowed selectivity of in vitro forangiogenesis HDAC1-4. byIn mouse-inducedparticular, from pluripotenta biological stempointcells of view, [66– 68the]. compound More recently, proved the totalto be synthesis a strong ofinhibitor all five of natural in vitro azumamides, angiogenesis as by well mouse-induced as their profiling pluripotent towards thestem whole cells panel[66–68]. of HDACs,MoreBiology recently, has 2020 been, 9 ,the x reported. total synthesis of all five natural azumamides, as well as their profiling11 oftowards 26 the whole panel of HDACs, has been reported.

Azumamide R1 R2 R3=R4 Yield (mg) a Yield (%) a IC50 (μM) b A NH2 H Me 2.7 1.2 × 10−4 (c) 0.045 B NH2 OH Me 1.6 7.3 × 10−5 0.11 C OH OH Me 1.4 6.4 × 10−5 0.11 D NH2 H H 0.6 2.7 × 10−5 1.3 E OH H Me 0.9 4.1 × 10−5 0.064

FigureFigure 13. Structures 13. Structures of azumamides of azumamides A-E. A-E. (a) Yield(a) Yield of azumamide of azumamide isolated isolated by extractionby extraction from from amarine a marine sponge. (b) Against the crude enzymes extracted from K562 cells. (c) Yield based on wet sponge. (b) Against the crude enzymes extracted from K562 cells. (c) Yield based on wet weight [65]. weight [65].

The data obtained revealed that azumamide C was a two-fold more potent inhibitor than azumamide E on the majority of HDAC isozymes. The observed discrepancy among the various evaluations of HDACi inhibitory activities was ascribed to the assay conditions largely affecting the results, underlining the need of their confirmation through parallel biological (e.g., antiproliferative or antiangiogenic) assays. On the other hand, surprisingly, given that the in vitro HDACi activity of azumamides B, C, and E were confirmed, no compound was able to reverse the chemoresistance caused by silencing of the proapoptotic Bim gene and, therefore, influence the growth of the Epstein−Barr virus (EBV)-infected human Burkitt’s lymphoma EB-3 cells differently from what was achieved upon treatment with HDACi SAHA [69,70]. This prompts a future investigation on azumamide analogs designed on the original scaffold but endowed with a more potent and selective ligand activity.

2.5. Cyclostellettamines and Dehydrocyclostellettamine The species of the genus Haliclona (Demospongiae, Haplosclerida: Chalinidae; Figure 14) are demosponges that live on poorly lit coral seaweed backdrops up to 40-m-deep in the Mediterranean Sea, the Western tropical Atlantic Ocean, the Caribbean Sea, the West Indies, and the Pacific coast. Some of these marine species are encrusting sponges with a fleshy but soft and fragile body. Their body is small and cone-shaped, with a maximum height of 8 cm, and their colonies can reach up to a diameter of 20 cm [71–73]. The species of the genus Xestospongia (Demospongiae, Haplosclerida: Petrosiidae; Figure 15) are typical of the Indian and South Pacific Oceans and represent an outstanding source of secondary metabolites with different biological properties against human diseases. Within the Xestospongia genus, Xestospongia vansoesti (Bakus and Nishiyama, 2000) is a benthic species, filter, and suspension feeder commonly distributed at depths of 8–12 m but occurring also between 3 and 32 m in the Eastern Philippines and Indian and South Pacific Oceans. This sponge forms thick crusts but can also be a digitiform and is characterized by the production of copious brown mucus when handled or damaged. Its dense multispicular tracts contain oxeas, and the intact surface is smooth, but the dermal membrane is often missing, and, in this case, the individual is microrugose [74].

Biology 2020, 9, 429 11 of 24

The data obtained revealed that azumamide C was a two-fold more potent inhibitor than azumamide E on the majority of HDAC isozymes. The observed discrepancy among the various evaluations of HDACi inhibitory activities was ascribed to the assay conditions largely affecting the results, underlining the need of their confirmation through parallel biological (e.g., antiproliferative or antiangiogenic) assays. On the other hand, surprisingly, given that the in vitro HDACi activity of azumamides B, C, and E were confirmed, no compound was able to reverse the chemoresistance caused by silencing of the proapoptotic Bim gene and, therefore, influence the growth of the Epstein Barr − virus (EBV)-infected human Burkitt’s lymphoma EB-3 cells differently from what was achieved upon treatment with HDACi SAHA [69,70]. This prompts a future investigation on azumamide analogs designed on the original scaffold but endowed with a more potent and selective ligand activity.

2.5. Cyclostellettamines and Dehydrocyclostellettamine The species of the genus Haliclona (Demospongiae, Haplosclerida: Chalinidae; Figure 14) are demosponges that live on poorly lit coral seaweed backdrops up to 40-m-deep in the Mediterranean Sea, the Western tropical Atlantic Ocean, the Caribbean Sea, the West Indies, and the Pacific coast. Some of these marine species are encrusting sponges with a fleshy but soft and fragile body. Their body is small and cone-shaped, with a maximum height of 8 cm, and their colonies can reach up to a diameter of 20 cm [71–73]. The species of the genus Xestospongia (Demospongiae, Haplosclerida: Petrosiidae; Figure 15) are typical of the Indian and South Pacific Oceans and represent an outstanding source of secondary metabolites with different biological properties against human diseases. Within the Xestospongia genus, Xestospongia vansoesti (Bakus and Nishiyama, 2000) is a benthic species, filter, and suspension feeder commonly distributed at depths of 8–12 m but occurring also between 3 and 32 m in the Eastern Philippines and Indian and South Pacific Oceans. This sponge forms thick crusts but can also be a digitiform and is characterized by the production of copious brown mucus when handled or damaged. Its dense multispicular tracts contain oxeas, and the intact surface is smooth, but the dermal membrane is often missing, and, in this case, the individual is microrugose [74]. Biology 2020, 9, x 12 of 26

Figure 14. Two examples of species of the genus Haliclona..( (AA)) HaliclonaHaliclona implexiformis implexiformis (Hechtel,(Hechtel, 1965); 1965); taken fromfrom [75 ]. (B[75].) Haliclona (B) fascigeraHaliclona(Hentschel, fascigera 1912); (Hentschel, (CC BY-SA3.0) 1912);http:// www.marinespecies.org(CC BY-SA 3.0)/ photogallery.php?albumhttp://www.marinespecies.org/ph=714&picotogallery.php?album=714&pic=132819.=132819.

Figure 15. Two examples of species of the genus Xestospongia. (A) Xestospongia testudinaria (Lamark, 1815) taken from [76]. (B) Xestospongia muta (Schmidt, 1870) taken from https://commons.wikimedia.org/wiki/File:Reef3860_-_Flickr_-_NOAA_Photo_Library.jpg (CC BY 2.0).

Petrosia alfiani (de Voogd and van Soest, 2002; Demospongiae, Haplosclerida: Petrosiidae; Figure 16) is distributed up to 40 m in the coral reef of Spermonde Archipelago, off the Southwest coast of Sulawesi in Indonesia, growing as thick and robust masses on coral blocks and rubble or coral sand. Its body is characterized by voluminous branches, such as massive globular or thick arms. Numerous small drains may be present on the sponge surface, which is smooth and bristly, with a consistency that can be stony hard or compressible [77].

Biology 2020, 9, x 12 of 26 Biology 2020, 9, x 12 of 26

Figure 14. Two examples of species of the genus Haliclona. (A) Haliclona implexiformis (Hechtel, 1965); taken from [75]. (B) Haliclona fascigera (Hentschel, 1912); (CC BY-SA 3.0) Biology 2020, 9, 429 12 of 24 http://www.marinespecies.org/photogallery.php?album=714&pic=132819.

Figure 15. Two examples of species of the genus Xestospongia.(A) Xestospongia testudinaria (Lamark, Figure 15. Two examples of species of the genus Xestospongia. (A) Xestospongia testudinaria (Lamark, 1815) taken from [76]. (B) Xestospongia muta (Schmidt, 1870) taken from https://commons.wikimedia. 1815) taken from [76]. (B) Xestospongia muta (Schmidt, 1870) taken from org/wiki/File:Reef3860_-_Flickr_-_NOAA_Photo_Library.jpg (CC BY 2.0). https://commons.wikimedia.org/wiki/File:Reef3860_-_Flickr_-_NOAA_Photo_Library.jpg (CC BY 2.0). Petrosia alfiani (de Voogdand van Soest, 2002; Demospongiae, Haplosclerida: Petrosiidae; Figure 16) is distributed up to 40 m in the coral reef of Spermonde Archipelago, off the Southwest coast of Petrosia alfiani (de Voogd and van Soest, 2002; Demospongiae, Haplosclerida: Petrosiidae; Figure Sulawesi in Indonesia, growing as thick and robust masses on coral blocks and rubble or coral sand. 16) is distributed up to 40 m in the coral reef of Spermonde Archipelago, off the Southwest coast of Its body is characterized by voluminous branches, such as massive globular or thick arms. Numerous Sulawesi in Indonesia, growing as thick and robust masses on coral blocks and rubble or coral sand. small drains may be present on the sponge surface, which is smooth and bristly, with a consistency Its body is characterized by voluminous branches, such as massive globular or thick arms. Numerous that can be stony hard or compressible [77]. small drains may be present on the sponge surface,surface, whichwhich isis smoothsmooth andand bristly,bristly, withwith aa consistencyconsistency that can be ststony hard or compressible [77].

Figure 16. Specimen of Petrosia alfiani demosponge [75].

The species of the Haliclona and Xestospongia genus have proven to be good sources of natural HDACis. In 2004, Oku et al. [78] isolated cyclostellettamine A and three new cyclostellettamine alkaloids, i.e., cyclostellettamine G and dehydrocyclostellettamines D and E (Figure 17), from species of the genus Xestospongia, all displaying inhibitory activity with IC50 values in the range between 17 and 80 µM on HDAC preparations partially purified from K562 cells and exerting a moderate cytotoxic effect on HeLa human cervix carcinoma, P388 mouse leukemia, and 3Y1 rat fibroblastic cells. Biology 2020, 9, x 13 of 26

Biology 2020, 9, x Figure 16. Specimen of Petrosia alfiani demosponge [75]. 13 of 26

The species of the HaliclonaFigure 16.and Specimen Xestospongia of Petrosia genus alfiani have demosponge proven to [75]be .good sources of natural HDACis. In 2004, Oku et al. [78] isolated cyclostellettamine A and three new cyclostellettamine alkaloids,The i.e.,species cyclostellettamine of the Haliclona G andand Xestospongiadehydrocyclostellettamines genus have proven D and to E be (Figure good sources17), from of species natural HDACis. In 2004, Oku et al. [78] isolated cyclostellettamine A and three new cyclostellettamine of the genus Xestospongia, all displaying inhibitory activity with IC50 values in the range between 17 andalkaloids, 80 µM i.e., on cyclostellettamineHDAC preparations G and partially dehydrocyclostellettamines purified from K562 Dcells and and E (Figure exerting 17), a from moderate species cytotoxicof the genus effect Xestospongia on HeLa human, all displaying cervix carcinom inhibitorya, P388activity mouse with leukemia,IC50 values and in the3Y1 range rat fibroblastic between 17 cells.and 80 µM on HDAC preparations partially purified from K562 cells and exerting a moderate cytotoxic effect on HeLa human cervix carcinoma, P388 mouse leukemia, and 3Y1 rat fibroblastic

Biologycells.2020 , 9, 429 13 of 24

Figure 17. Structures of cyclostellettamine G (1), dehydrocyclostellettamine D (2), Figuredehydrocyclostellettamine 17. Structures of cyclostellettamine E, (3) and cyclostellettamine G (1), dehydrocyclostellettamine A (4) [78]. D (2), dehydrocyclostellettamine E,Figure (3) and cyclostellettamine17. StructuresA (4)of [78cyclostellettamine]. G (1), dehydrocyclostellettamine D (2), Moredehydrocyclostellettamine recently, Lee et al. [79] E, (3) isolated and cyclostellettamine eight novel cyclic A (4) bis-1,3-dialkylpyridinium[78]. compounds, More recently, Lee et al. [79] isolated eight novel cyclic bis-1,3-dialkylpyridinium compounds, as well as the two cyclostellettamines N and Q, from a species of the genus Haliclona (Figure 18), as well as the two cyclostellettamines N and Q, from a species of the genus Haliclona (Figure 18), which Moreexhibited recently, a moderate Lee et al. doxorubicin-comparable [79] isolated eight novel cytotoxicity cyclic bis-1,3-dialkylpyridinium towards A549 lung cancercompounds, cells which exhibited a moderate doxorubicin-comparable cytotoxicity towards A549 lung cancer cells and, and,as well also, as a the diverse two cyclostellettamines range of antimicrobial N and activity Q, from specifically a species ofdirected the genus against Haliclona Gram-positive (Figure 18), also, a diverse range of antimicrobial activity specifically directed against Gram-positive bacterial strains. bacterialwhich exhibited strains. a moderate doxorubicin-comparable cytotoxicity towards A549 lung cancer cells and, also, a diverse range of antimicrobial activity specifically directed against Gram-positive bacterial strains.

Figure 18. Structures of cyclostellettamine N (1), cyclostellettamine Q (2), and the other eight bis-1,3-dialkylpyridinium compounds extracted from species of the genus Haliclona (3–10). Figure 18. Structures of cyclostellettamine N (1), cyclostellettamine Q (2), and the other eight bis-1,3- 2.6. Halenaquinonesdialkylpyridinium compounds extracted from species of the genus Haliclona (3–10). Figure 18. Structures of cyclostellettamine N (1), cyclostellettamine Q (2), and the other eight bis-1,3- X. vansoesti and P. alfiani produce the polycyclic quinone-type metabolite halenaquinone 2.6. Halenaquinonesdialkylpyridinium compounds extracted from species of the genus Haliclona (3–10). (Figure 19) found to induce the inhibition of pan-HDACs and, in addition, also, topoisomerase IIα2.6.expression,X. Halenaquinones vansoesti the and latter P. alfiani resulting produce in the the switching-o polycyclicff quinone-typeof DNA replication. metabolite Dealing halenaquinone with the biological (Figure aspects,19) found Shih to et induce al. [80 ]the demonstrated inhibition itsof cytotoxicpan-HDACs activity and, on in a numberaddition, of also, cancer topoisomerase cell lines, being IIα X. vansoesti and P. alfiani produce the polycyclic quinone-type metabolite halenaquinone (Figure particularly remarkable against Molt 4 leukemia cells, in which viability suppression and apoptosis promotion19) found following to induce reactive the oxygeninhibition species of pan-HD (ROS)-inducedACs and, mitochondrial in addition, dysfunction also, topoisomerase was observed. IIα The molecular signatures associated to the exposure of leukemia cells to the molecule were the upregulation of cytochrome c of the proapoptotic protein Bax, of the cytosolic hexokinase I, and of the active forms of caspase 8 and -9 and the downregulation of the antiapoptotic proteins Bcl-2, Bid, and cytosolic hexokinase II and of the phosphorylated (activated) forms of Akt, phosphatase, and tensin homolog (PTEN), glycogen synthase kinase 3 β (GSK3β), and phosphoinositide-dependent kinase-1 (PDK1). Of note, halenaquinone exhibited also a potent in vivo antileukemic effect in mice xenograft assays, reducing the weight and size of the tumor mass without affecting the total mice weight. Biology 2020, 9, x 14 of 26 expression, the latter resulting in the switching-off of DNA replication. Dealing with the biological aspects, Shih et al. [80] demonstrated its cytotoxic activity on a number of cancer cell lines, being particularly remarkable against Molt 4 leukemia cells, in which viability suppression and apoptosis promotion following reactive oxygen species (ROS)-induced mitochondrial dysfunction was observed. The molecular signatures associated to the exposure of leukemia cells to the molecule were the upregulation of cytochrome c of the proapoptotic protein Bax, of the cytosolic hexokinase I, and of the active forms of caspase 8 and -9 and the downregulation of the antiapoptotic proteins Bcl-2, Bid, and cytosolic hexokinase II and of the phosphorylated (activated) forms of Akt, phosphatase, and tensin homolog (PTEN), glycogen synthase kinase 3 β (GSK3β), and phosphoinositide- dependent kinase-1 (PDK1). Of note, halenaquinone exhibited also a potent in vivo antileukemic effect in mice xenograft assays, reducing the weight and size of the tumor mass without affecting the total mice weight. In addition, Takaku et al. [81] demonstrated the inhibitory activity of the compound on DNA homologous pairing by direct binding to RAD51 enzyme, involved in the repair of DNA double- strand breaks, and subsequent likely competition with the double-strand DNA in the secondary DNA-binding site within the RAD51–single-strand DNA filament complex. More recently, Tsukamoto et al. [82] identified 65 as an inhibitor of the receptor activator of nuclear factor-κB ligand (RANKL)-induced upregulation of tartrate-resistant acid phosphatase (TRAP), which is involved in cell fusion, leading to the formation of multinucleated osteoclasts. Biology 2020, 9, 429 14 of 24

Figure 19. Structure of halenaquinone. Figure 19. Structure of halenaquinone. In addition, Takaku et al. [81] demonstrated the inhibitory activity of the compound on DNA 3. Cnidariahomologous pairing by direct binding to RAD51 enzyme, involved in the repair of DNA double-strand breaks, and subsequent likely competition with the double-strand DNA in the secondary DNA-binding Cnidarians constitute the first metazoan phylum endowed with a well-developed degree of site within the RAD51–single-strand DNA filament complex. More recently, Tsukamoto et al. [82] tissue organization and gather polymorphic aquatic animals displaying radial or biradial symmetry identified 65 as an inhibitor of the receptor activator of nuclear factor-κB ligand (RANKL)-induced and a single central body cavity (the “coelenteron”) with a mouth and tentacles but lacking an anus. upregulation of tartrate-resistant acid phosphatase (TRAP), which is involved in cell fusion, leading to Xenia elongata (Dana, 1846; Anthozoa, Alcyonacea: Xeniidae) is a photosynthetic soft marine the formation of multinucleated osteoclasts. coral that can be found in the Indian and Pacific Oceans and the Red Sea often clinging to the vertical surface3. Cnidaria of rocks between 0 and 10 m deep in order to obtain sufficient light and be exposed to strong currents. These organisms display a soft, fleshy, and feathered body with feather-shaped tentacles Cnidarians constitute the first metazoan phylum endowed with a well-developed degree of tissue similar to fingers used to stir water with a constant and grabbing motion (Figure 20). For this reason, organization and gather polymorphic aquatic animals displaying radial or biradial symmetry and a the species of this genus are commonly known as “pulse corals” [83]. single central body cavity (the “coelenteron”) with a mouth and tentacles but lacking an anus. Xenia elongata (Dana, 1846; Anthozoa, Alcyonacea: Xeniidae) is a photosynthetic soft marine coral that can be found in the Indian and Pacific Oceans and the Red Sea often clinging to the vertical surface of rocks between 0 and 10 m deep in order to obtain sufficient light and be exposed to strong currents. These organisms display a soft, fleshy, and feathered body with feather-shaped tentacles similar to fingers used to stir water with a constant and grabbing motion (Figure 20). For this reason, the species

ofBiology this 2020 genus, 9, x are commonly known as “pulse corals” [83]. 15 of 26

FigureFigure 20.20. SpecimenSpecimen ofof XeniaXenia elongataelongata softsoft coral.coral. ((AA)) PhotoPhoto ofof holotypeholotype inin drydry conditions.conditions. ((BB)) ColonyColony drawingdrawing fromfrom DanaDana (1846)(1846) [[84].84].

AndrianasoloAndrianasolo etet al.al. [[85]85] isolatedisolated aa newnew diterpenediterpene fromfrom X.X. elongataelongata (Figure(Figure 2121),), whichwhich promotedpromoted thethe programmedprogrammed deathdeath ofof immortalizedimmortalized apoptosis-competentapoptosis-competent W2 cells at a 1.2-1.2-µMµM concentration.concentration. FurtherFurther enzymaticenzymatic inhibition inhibition tests tests against against the the class class I, -III, -II A, A, and and the th -IIe B-II HDACs B HDACs demonstrated demonstrated that that the the compound specifically inhibited class II B HDAC6 with an IC50 of about 80 µM. In light of the data obtained, this molecule represents a new model structure of selective HDAC inhibitor that may be used for the development of novel HDAC isoform-targeting drugs.

Figure 21. Structure of the diterpene extracted from X. elongata [85].

4. Echinodermata Echinoderms are marine invertebrates endowed with a hard, spiny covering or skin. Holopus rangii (Orbigny, 1837; Crinoidea, Cyrtocrinida: Holopodidae, Figure 22) is a large sessile but nonpedunculated crinoid populating the depths of Caribbean slopes and around Roatan Island, Honduras. It represents one of only eight extant species of Cyrtocrinida, an enigmatic invertebrate group diversified during the Jurassic age. Its skeleton is made up of thick plaques that are connected with sparse muscle joints. Its calyx is typically tubular, somewhat irregular, and the upper edge is grossly pentagonal. This organism is equipped with robust arms curved inwards with radials that can show different sizes [86].

Biology 2020, 9, x 15 of 26

Figure 20. Specimen of Xenia elongata soft coral. (A) Photo of holotype in dry conditions. (B) Colony drawing from Dana (1846) [84].

Andrianasolo et al. [85] isolated a new diterpene from X. elongata (Figure 21), which promoted Biologythe programmed2020, 9, 429 death of immortalized apoptosis-competent W2 cells at a 1.2-µM concentration.15 of 24 Further enzymatic inhibition tests against the class I, -II A, and the -II B HDACs demonstrated that the compound specifically inhibited class II B HDAC6 with an IC50 of about 80 µM. In light of the compound specifically inhibited class II B HDAC6 with an IC50 of about 80 µM. In light of the data obtained,data obtained, this molecule this molecule represents represents a new a model new mode structurel structure of selective of selective HDAC HDAC inhibitor inhibitor that maythat may be usedbe used for the for development the development of novel of novel HDAC HDAC isoform-targeting isoform-targeting drugs. drugs.

Figure 21. Structure of the diterpene extracted from X. elongata [85]. 4. Echinodermata Figure 21. Structure of the diterpene extracted from X. elongata [85]. Echinoderms are marine invertebrates endowed with a hard, spiny covering or skin. Holopus rangii 4. Echinodermata (Orbigny, 1837; Crinoidea, Cyrtocrinida: Holopodidae, Figure 22) is a large sessile but nonpedunculated crinoidEchinoderms populating the are depths marine of invert Caribbeanebrates slopes endowed and around with a Roatan hard, Island,spiny covering Honduras. or Itskin. represents Holopus onerangii of only (Orbigny, eight extant 1837; species Crinoidea, of Cyrtocrinida, Cyrtocrinida: an enigmaticHolopodidae, invertebrate Figure group22) is diversifieda large sessile during but thenonpedunculated Jurassic age. Its skeletoncrinoid ispopulating made up ofthe thick depths plaques of Caribbean that are connected slopes and with around sparse muscleRoatan joints.Island, ItsHonduras. calyx is typically It represents tubular, one somewhat of only eight irregular, extant andspecies the of upper Cyrtocrinida, edge is grossly an enigmatic pentagonal. invertebrate This Biology 2020, 9, x 16 of 26 organismgroup diversified is equipped during with robustthe Jurassic arms age. curved Its skeleton inwards withis made radials up of that thick can plaques show di thatfferent are sizes connected [86]. with sparse muscle joints. Its calyx is typically tubular, somewhat irregular, and the upper edge is grossly pentagonal. This organism is equipped with robust arms curved inwards with radials that can show different sizes [86].

Figure 22. Specimen of Holopus rangii crinoid. Muséum national d’Histoire naturelle, Paris (France), Collection:Figure 22. Specimen Echinoderms of Holopus (IE), Specimen rangii crinoid. MNHN-IE-2013-10116; Muséum national http: d’Hist//coldb.mnhn.froire naturelle,/catalognumber Paris (France),/ mnhnCollection:/ie/2013-10116 . Echinoderms (IE), Specimen MNHN-IE-2013-10116; http://coldb.mnhn.fr/catalognumber/mnhn/ie/2013-10116.

From H. rangii, Kemami Wangun et al. [87] isolated a novel member of the phenanthrol perylenequinone family of natural products denominated gymnochrome E (Figure 23) that showed an inhibitory activity towards purified HDAC-1 with an IC50 of 10.9 µM and selectively restrained the growth of the multidrug-resistant NCI/ADRRes ovarian cancer cell line with an IC50 value of 3.5 µM while exerting no effect on PANC-1 pancreatic carcinoma and DLD-1 human colorectal adenocarcinoma cell lines. Moreover, the compound appeared endowed with an antimicrobic activity against Staphylococcus aureus and its methicillin-resistant strain with a minimum inhibitory concentration of 25 µg/mL but not against Pseudomonas aeruginosa and Candida albicans.

Figure 23. Structure of gymnochrome E.

5. Conclusions It is widely acknowledged that the enormous biodiversity of the marine habitats represents a source of immeasurable value for the isolation of very disparate bioactive secondary metabolites from

Biology 2020, 9, x 16 of 26

Figure 22. Specimen of Holopus rangii crinoid. Muséum national d’Histoire naturelle, Paris (France), Collection: Echinoderms (IE), Specimen MNHN-IE-2013-10116; http://coldb.mnhn.fr/catalognumber/mnhn/ie/2013-10116. Biology 2020, 9, 429 16 of 24 From H. rangii, Kemami Wangun et al. [87] isolated a novel member of the phenanthrol perylenequinone family of natural products denominated gymnochrome E (Figure 23) that showed anFrom inhibitoryH. rangii, activityKemami towards Wangun purified et al.HDAC-1 [87] isolated with an aIC novel50 of 10.9 member µM and of theselectively phenanthrol restrained perylenequinonethe growth of family the multidrug-resistant of natural products NCI/ADRRes denominated ovarian gymnochrome cancer cell E (Figureline with 23 an) that IC50 showed value of 3.5 an inhibitoryµM while activity exerting towards no effect purified on HDAC-1PANC-1 withpancreatic an IC50 carcinomaof 10.9 µM and and DLD-1 selectively human restrained colorectal the growthadenocarcinoma of the multidrug-resistant cell lines. Moreover, NCI/ ADRResthe compound ovarian appeared cancer cell endowed line with with an IC an50 valueantimicrobic of 3.5 µactivityM while against exerting Staphylococcus no effect on aureus PANC-1 and its pancreatic methicillin-resistant carcinomaand strain DLD-1 with a human minimum colorectal inhibitory adenocarcinomaconcentration cell of lines.25 µg/mL Moreover, but not the against compound Pseudomonas appeared aeruginosa endowed and with Candida an antimicrobic albicans. activity against Staphylococcus aureus and its methicillin-resistant strain with a minimum inhibitory concentration of 25 µg/mL but not against Pseudomonas aeruginosa and Candida albicans.

Figure 23. Structure of gymnochrome E.

5. Conclusions Figure 23. Structure of gymnochrome E.

5.It Conclusions is widely acknowledged that the enormous biodiversity of the marine habitats represents a source of immeasurable value for the isolation of very disparate bioactive secondary metabolites from It is widely acknowledged that the enormous biodiversity of the marine habitats represents a bacteria, plants, and animals whose number is expected to increase rapidly, e.g., [88]. Among the source of immeasurable value for the isolation of very disparate bioactive secondary metabolites from enzymatic inhibitors searched in extracts from marine organisms, a focus has been put on HDACis for their wide range of biomedical applications. Natural inhibitors have been isolated from aquatic microorganisms [89,90], and, as documented by the studies presented in this review, also, marine invertebrates have contributed with a number of compounds displaying impairing properties of various potency towards HDACs, demosponges being the most investigated to date. Table1 reports a schematic outline of the procedures used for the extraction, isolation, and identification of the HDACis from the marine organisms, whereas Table2 summarizes, in a synoptic way, the invertebrate species, the isolated molecules, and their observed effects discussed in the text. It is worth mentioning that some marine species-derived molecules showing structural similarities with known HDACis failed to exert HDACi-referable cellular and molecular effects, as in the case of SAHA- and trichostatin A-resembling N-(4-guanidinobutyl)-2-(4-hydroxy phenyl)-2-oxo-acetamide isolated from the cnidarian hydroid Campanularia sp. [91]. Therefore, a thorough biological characterization of the novel compounds identified in the future, including the identification of the specific, if any, target cytotype(s), appears to be a necessary aspect for the subsequent development of efficacious prevention and/or treatment agents against different pathological states—among them, cancers. On the other hand, the unique and peculiar chemical scaffolds presented by the marine-derived HDACis may be successfully utilized for the design of analogs with increased bioavailability and efficacy, less toxicity, and, also, very interestingly, higher isoform selectivity. Biology 2020, 9, 429 17 of 24

Table 1. Extraction, isolation, and identification procedures for the inhibitory histone deacetylases (HDACis) from marine invertebrates.

Compound Extraction and Isolation Identification Ref. Extraction in EtOH and MetOH, partitioning between Inhibition assay with water and Et O, further extraction with nBuOH, Azumamides 2 crude enzymes extracted [56] octadecylsilane flash chromatography, gel filtration from K562 cells and octadecylsilane HPLC Extraction with EtOH, partitioning between water and Et2O, further extraction with nBuOH, separation by octadecylsilane flash chromatography, further partitioning between CH2Cl2 and 60% MeOH, Inhibition assay with Cyclostelletamine A and G fractionation of the latter layer by octadecylsilane HDACs partially Dehydrocyclostelletamine D (aqueous MeOH), TSK G3000S (aqueous MeCN–5% purified from K562 cells [64] 3 and E from Haliclona sponges AcOH), and Sephadex LH-20 (CHCl3–MeOH, 1:1) and [ H] acetyl chromatography, further purification by HPLC on histoneH4 peptide phenylethyl-SiO2 (MeCN–H2O, 52:48, containing 0.1% TFA) and finally by HPLC on C30-SiO2 (aqueous n-PrOH containing 0.1% TFA)

Extraction with CH2Cl2 and then with MeOH, fractionation of the polar crude organic fraction by solid phase extraction cartridge (Reverse-phase C18), Inhibition assay with Diterpene from X. elongata chromatography of the fraction eluting with 15% H2O isolated HDACs and [69] and 85% MeOH on analytical RP HPLC (Phenomenex fluorogenic substrates luna C8) using a gradient elution (starting with 80% water and 20% CH3CN Successive extractions with EtOH and EtOAc/EtOH Inhibition assay with (1:1), fractionation on a C-18 stationary phase using HDACs partially Gymnochromes E and F vacuum column chromatography, further purification purified from H1299 cells [70] using reversed and [3H] acetyl phase HPLC histoneH4 peptide

Extraction with MeOH, partitioning between CHCl3 and water, dissolution of the evaporated organic layer Commercial HDAC into water⁄ MeOHl (1:9), extraction with CHCl , Inhibitor Drug Screening Halenaquinone 3 [66,67] fractionation and purification by reversed-phase HPLC assay (BioVision, on a C18 column with aqueous acetonitrile Milpitas, CA, USA) (water:acetonitrile 7:3–3:7, linear gradient

Extraction with MeOH, CHCl3, and then, n-BuOH, Kupchan procedure to yield an aqueous MeOH layer, SIRT1–3 inhibitory tests separation by octadecylsilane flash chromatography by electrophoretic Halistanol sulphates (water/MeOH = 100/0, 80/20, 50/50, 30/70, 0/100, [54] mobility and CHCl /MeOH/water = 6/4/1), separation of the 3 shift assay fraction eluting with water/MeOH = 50/50 by reverse-phase HPLC Extraction with 50% MeOH in CH Cl , separation by 2 2 Commercial luminescent Sephadex LH-20 column (eluted with CH Cl /MeOH, 2 2 assay Psammaplins and bisaprasin 50:50), separation of the active fraction by a [45] (HDAC-Glo™, Promega, semi-preparative HPLC (C18(2), isocratic 63% MeOH Madison, WI, USA) in water) Extraction with MeOH and EtOH, partitioning with CHCl3 and water and, then, between 90% MeOH and n-hexane, separation of the CHCl3 layer by octadecylsilane flash chromatography using a stepwise gradient elution (20 70% MeOH, 70 90% MeCN, − − Inhibition assay with and MeOH), separation of the active fraction by Yakushinamides recombinant SIRTs and [52] chromatography on silica gel using a stepwise gradient fluorogenic substrates elution (CHCl MeOH water, 98:2:0, 9:1:0, 8:2:0.1, 3− − 7:3:0.5, 6:4:1, and 5:5:1), separation by RP-HPLC using two columns connected in tandem with eluent consisting of 8:2 MeOH phosphate buffer, purification − by RP-HPLC with 5:5 MeCN phosphate buffer − Biology 2020, 9, 429 18 of 24

Table 2. Properties of HDACis from marine invertebrates.

Phylum Species Compounds Effects Ref. Activation of peroxisome proliferator-activated receptor γ (PPARγ) in MCF-7 cells and promotion of apoptotic death psammaplin A HDAC isoform selectivity [48] (e,z)-psammaplin A Powerful inhibition of the proliferation and three-dimensional [49] (e,e)-psammaplin A invasive growth of tumor cells, stimulation of the activity of [50] psammaplin E hypoxia-inducible factor (HIF) and upregulation of HIF [51] Aplysinella rhax psammaplin K target genes Pseudoceratina purpurea sub Psammaplysilla Growth inhibition and apoptosis promotion on Ishikawa purpurea endometrial cancer cells Ernstilla lacunose sub Dendrilla lacunosa Powerful inhibition of carbonic anhydrase XII Jaspis sp. Anticancer effect against the highly chemorefractory stem Poecillastra wondoensis component of glioblastoma cells [52] psammaplin A Stimulation of the expression and phosphorylation of TP53 [53] psammaplin C family members [55] psammaplin A-3091 Cytotoxicity towards MCF-7 breast cancer and A549 lung [49] cancer cells [56] Significant in vitro and in vivo anti-breast tumorigenesis and antimetastatic activity Theonella swinhoei yakushinamide A Moderate inhibitory effect on HDACs and sirtuins [58] halistanol sulphate Porifera Halichondria sp. halistanol sulphate I Inhibitory activity on SIRT1-3 [62] halistanol sulphate J Moderate cytostatic effect on K562 human leukemia cells and azumamides A-E significant anti-angiogenic effect on mouse vascular progenitor azumamide A cells. Inhibitory activity on total HDACs from HeLa cell extracts [65] Mycale izuensis azumamide E with selectivity for HDAC1-4. [66–68] azumamide C Strong inhibition of in vitro angiogenesis by mouse induced pluripotent stem cells Moderate doxorubicin-comparable cytotoxicity towards A549 cyclostellettamine N Haliclona sp. lung cancer cells and antimicrobial activity against [79] cyclostellettamine Q Gram-positive bacteria cyclostellettamine A cyclostellettamine G Moderate cytotoxic effect on HeLa human cervix carcinoma, P388 Xestospongia sp. [78] dehydrocyclostellettamine D mouse leukemia, and 3Y1 rat fibroblastic cells dehydrocyclostellettamine E Inhibitory activity on DNA repair and on receptor activator of Xestospongia vansoesti halenaquinone [58,81] nuclear factor-κB ligand-mediated osteoclast maturation Inhibition of pan-HDACs and topoisomerase IIα expression, polycyclic quinone-type metabolite Petrosia alfiani cytotoxic activity against Molt 4 leukemia cells and [80] halenaquinone in vivo antileukemic effect in mice xenograft assays Biology 2020, 9, 429 19 of 24

Table 2. Cont.

Phylum Species Compounds Effects Ref. Induction of programmed death of immortalized Cnidaria Xenia elongata diterpene [85] apoptosis-competent W2 cells and inhibition of class II B HDAC6 Inhibitory activity towards purified HDAC-1 and selective growth impairment of the multidrug-resistant NCI/ADRRes Echinodermata Holopus rangii gymnochrome E [87] ovarian cancer cell line. Antimicrobic activity against Staphylococcus aureus and its methicillin-resistant strain Biology 2020, 9, 429 20 of 24

Author Contributions: C.L., M.M., V.A., and M.V. collected the references, and C.L. and M.V. wrote the paper. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by The University of Palermo (Italy), grant Fondo Finalizzato alla Ricerca (FFR) 2018 to C.L. and M.V. Conflicts of Interest: The authors declare no conflict of interest.

References

1. Ali, I.; Conrad, R.J.; Verdin, E.; Ott, M. Lysine Acetylation Goes Global: From Epigenetics to Metabolism and Therapeutics. Chem. Rev. 2018, 118, 1216–1252. [CrossRef][PubMed] 2. Voutsinas, G.E.; Scorilas, A.; Stravopodis, D.J. Revisiting Histone Deacetylases in Human Tumorigenesis: The Paradigm of Urothelial Bladder Cancer. Int. J. Mol. Sci. 2019, 20, 1291. 3. Hassell, K.N. Histone Deacetylases and their Inhibitors in Cancer Epigenetics. Diseases 2019, 7, 57. [CrossRef] [PubMed] 4. Chaturvedi, N.K.; Hatch, N.D.; Sutton, G.L.; Kling, M.; Vose, J.M.; Joshi, S.S. A novel approach to eliminate therapy-resistant mantle cell lymphoma: Synergistic effects of Vorinostat with Palbociclib. Leuk. Lymphoma 2019, 60, 1214–1223. [CrossRef][PubMed] 5. Elmallah, M.I.Y.; Micheau, O. Epigenetic Regulation of TRAIL Signaling: Implication for Cancer Therapy. Cancers 2019, 11, 850. [CrossRef][PubMed] 6. Librizzi, M.; Longo, A.; Chiarelli, R.; Amin, J.; Spencer, J.; Luparello, C. Cytotoxic effects of Jay Amin hydroxamic acid (JAHA), a ferrocene-based class I histone deacetylase inhibitor, on triple-negative MDA-MB231 breast cancer cells. Chem. Res. Toxicol. 2012, 25, 2608–2616. [CrossRef] 7. Librizzi, M.; Chiarelli, R.; Bosco, L.; Sansook, S.; Gascon, J.M.; Spencer, J.; Caradonna, F.; Luparello, C. The Histone Deacetylase Inhibitor JAHA Down-Regulates pERK and Global DNA Methylation in MDA-MB231 Breast Cancer Cells. Materials 2015, 8, 7041–7047. [CrossRef] 8. Librizzi, M.; Spencer, J.; Luparello, C. Biological Effect of a Hybrid Anticancer Agent Based on Kinase and Histone Deacetylase Inhibitors on Triple-Negative (MDA-MB231) Breast Cancer Cells. Int. J. Mol. Sci. 2016, 17, 1235. [CrossRef] 9. Librizzi, M.; Caradonna, F.; Cruciata, I.; D˛ebski,J.; Sansook, S.; Dadlez, M.; Spencer, J.; Luparello, C. Molecular Signatures Associated with Treatment of Triple-Negative MDA-MB231 Breast Cancer Cells with Histone Deacetylase Inhibitors JAHA and SAHA. Chem. Res. Toxicol. 2017, 30, 2187–2196. [CrossRef] 10. Huang, M.; Zhang, J.; Yan, C.; Li, X.; Zhang, J.; Ling, R. Small molecule HDAC inhibitors: Promising agents for breast cancer treatment. Bioorg. Chem. 2019, 91, 103184. [CrossRef] 11. Luparello, C.; Asaro, D.M.L.; Cruciata, I.; Hassell-Hart, S.; Sansook, S.; Spencer, J.; Caradonna, F. Cytotoxic Activity of the Histone Deacetylase 3-Selective Inhibitor Pojamide on MDA-MB-231 Triple-Negative Breast Cancer Cells. Int. J. Mol. Sci. 2019, 20, 804. [CrossRef][PubMed] 12. Kim, B.; Hong, J. An overview of naturally occurring histone deacetylase inhibitors. Curr. Top. Med. Chem. 2015, 14, 2759–2782. [CrossRef][PubMed] 13. Lakshmaiah, K.C.; Jacob, L.A.; Aparna, S.; Lokanatha, D.; Saldanha, S.C. Epigenetic therapy of cancer with histone deacetylase inhibitors. J. Cancer Res. Ther. 2014, 10, 469–478. [PubMed] 14. He, B.; Dai, L.; Zhang, X.; Chen, D.; Wu, J.; Feng, X.; Zhang, Y.; Xie, H.; Zhou, L.; Wu, J.; et al. The HDAC Inhibitor Quisinostat (JNJ-26481585) Supresses Hepatocellular Carcinoma alone and Synergistically in

Combination with Sorafenib by G0/G1 phase arrest and Apoptosis induction. Int. J. Biol. Sci. 2018, 14, 1845–1858. [CrossRef][PubMed] 15. Hrgovic, I.; Doll, M.; Pinter, A.; Kaufmann, R.; Kippenberger, S.; Meissner, M. Histone deacetylase inhibitors interfere with angiogenesis by decreasing endothelial VEGFR-2 protein half-life in part via a VE-cadherin-dependent mechanism. Exp. Dermatol. 2017, 26, 194–201. [CrossRef] 16. Su, Y.; Hopfinger, N.R.; Nguyen, T.D.; Pogash, T.J.; Santucci-Pereira, J.; Russo, J. Epigenetic reprogramming of epithelial mesenchymal transition in triple negative breast cancer cells with DNA methyltransferase and histone deacetylase inhibitors. J. Exp. Clin. Cancer Res. 2018, 37, 314. [CrossRef] 17. Brandão, F.A.; Derengowski, L.S.; Albuquerque, P.; Nicola, A.M.; Silva-Pereira, I.; Poças-Fonseca, M.J. Histone deacetylases inhibitors effects on Cryptococcus neoformans major virulence phenotypes. Virulence 2015, 6, 618–630. [CrossRef] Biology 2020, 9, 429 21 of 24

18. Chopra, V.; Quinti, L.; Khanna, P.; Paganetti, P.; Kuhn, R.; Young, A.B.; Kazantsev, A.G.; Hersch, S. LBH589, A Hydroxamic Acid-Derived HDAC Inhibitor, is Neuroprotective in Mouse Models of Huntington’s Disease. J. Huntingt. Dis. 2016, 5, 347–355. [CrossRef] 19. Soragni, E.; Gottesfeld, J.M. Translating HDAC inhibitors in Friedreich’s ataxia. Expert Opin. Orphan Drugs 2016, 4, 961–970. [CrossRef] 20. Lai, J.I.; Leman, L.J.; Ku, S.; Vickers, C.J.; Olsen, C.A.; Montero, A.; Ghadiri, M.R.; Gottesfeld, J.M. Cyclic tetrapeptide HDAC inhibitors as potential therapeutics for spinal muscular atrophy: Screening with iPSC-derived neuronal cells. Bioorg. Med. Chem. Lett. 2017, 27, 3289–3293. [CrossRef] 21. Brindisi, M.; Saraswati, A.P.; Brogi, S.; Gemma, S.; Butini, S.; Campiani, G. Old but Gold: Tracking the New Guise of Histone Deacetylase 6 (HDAC6) Enzyme as a Biomarker and Therapeutic Target in Rare Diseases. J. Med. Chem. 2020, 63, 23–39. [CrossRef][PubMed] 22. Vazzana, M.; Celi, M.; Maricchiolo, G.; Genovese, L.; Corrias, V.; Quinci, E.M.; de Vincenzi, G.; Maccarrone, V.; Cammilleri, G.; Mazzola, S.; et al. Are mussels able to distinguish underwater sounds? Assessment of the reactions of Mytilus galloprovincialis after exposure to lab-generated acoustic signals. Comp. Biochem. Physiol. A Mol. Integr. Physiol. 2016, 201, 61–70. [CrossRef][PubMed] 23. Parisi, M.G.; Mauro, M.; Sarà, G.; Cammarata, M. Temperature increases, hypoxia, and changes in food availability affect immunological biomarkers in the marine mussel Mytilus galloprovincialis. J. Comp. Physiol. B 2017, 187, 1117–1126. [CrossRef][PubMed] 24. Vazzana, M.; Ceraulo, M.; Mauro, M.; Papale, E.; Dioguardi, M.; Mazzola, S.; Arizza, V.; Chiaramonte, M.; Buscaino, G. Effects of acoustic stimulation on biochemical parameters in the digestive gland of Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1819). J. Acoust. Soc. Am. 2020, 147, 2414. [CrossRef][PubMed] 25. Vazzana, M.; Mauro, M.; Ceraulo, M.; Dioguardi, M.; Papale, E.; Mazzola, S.; Arizza, V.; Beltrame, F.; Inguglia, L.; Buscaino, G. Underwater high frequency noise: Biological responses in sea urchin Arbacia lixula (Linnaeus, 1758). Comp. Biochem. Physiol. A Mol. Integr. Physiol. 2020, 242, 110650. [CrossRef][PubMed] 26. Hay, M.E. Marine chemical ecology: Chemical signals and cues structure marine populations, communities, and ecosystems. Ann. Rev. Mar. Sci. 2009, 1, 193–212. [CrossRef][PubMed] 27. Liu, L.; Zheng, Y.; Shao, C.; Wang, C. Metabolites from marine invertebrates and their symbiotic microorganisms: Molecular diversity discovery, mining, and application. Mar. Life Sci. Technol. 2019, 1, 60–94. [CrossRef] 28. Lazzara, V.; Arizza, V.; Luparello, C.; Mauro, M.; Vazzana, M. Bright Spots in the Darkness of Cancer: A Review of Starfishes-Derived Compounds and Their Anti-Tumor Action. Mar. Drugs 2019, 17, 617. [CrossRef] 29. Luparello, C.; Ragona, D.; Asaro, D.M.L.; Lazzara, V.; Affranchi, F.; Celi, M.; Arizza, V.; Vazzana, M. Cytotoxic Potential of the Coelomic Fluid Extracted from the Sea Cucumber Holothuria tubulosa against Triple-Negative MDA-MB231 Breast Cancer Cells. Biology 2019, 8, 76. [CrossRef] 30. Luparello, C.; Ragona, D.; Asaro, D.M.L.; Lazzara, V.; Affranchi, F.; Arizza, V.; Vazzana, M. Cell-Free Coelomic Fluid Extracts of the Sea Urchin Arbacia lixula Impair Mitochondrial Potential and Cell Cycle Distribution and Stimulate Reactive Oxygen Species Production and Autophagic Activity in Triple-Negative MDA-MB231 Breast Cancer Cells. J. Mar. Sci. Eng. 2020, 8, 261. [CrossRef] 31. Luparello, C.; Mauro, M.; Lazzara, V.; Vazzana, M. Collective Locomotion of Human Cells, Wound Healing and Their Control by Extracts and Isolated Compounds from Marine Invertebrates. Molecules 2020, 25, 2471. [CrossRef][PubMed] 32. Mauro, M.; Lazzara, V.; Punginelli, D.; Arizza, V.; Vazzana, M. Antitumoral compounds from vertebrate sister group: A review of Mediterranean ascidians. Dev. Comp. Immun. 2020, 108, 103669. [CrossRef][PubMed] 33. Van Soest, R.W.; Boury-Esnault, N.; Vacelet, J.; Dohrmann, M.; Erpenbeck, D.; De Voogd, N.J.; Santodomingo, N.; Vanhoorne, B.; Kelly, M.; Hooper, J.N. Global diversity of sponges (Porifera). PLoS ONE 2012, 7, e35105. [CrossRef][PubMed] 34. De Laubenfels, M.W. The Sponges of the West-Central Pacific; Oregon State Monographs: Studies in Zoology; Oregon State College: Corvallis, OR, USA, 1954; pp. 35–41. 35. Bergquist, P.R. The Sponges of Micronesia, Part I, The Palau Archipelago. Pac. Sci. 1965, 19, 123–204. 36. Bergquist, P.R.; Tizard, C.A. Australian Intertidal Sponges from the Darwin Area. Micronesica 1967, 3, 175–202. 37. Núñez Pons, L.; Calcinai, B.; Gates, R.D. Who’s there?—First morphological and DNA barcoding catalogue of the shallow Hawai’ian sponge fauna. PLoS ONE 2017, 12, e0189357. [CrossRef] Biology 2020, 9, 429 22 of 24

38. Vacelet, J.; Erpenbeck, D.; Díaz, C.; Ehrlich, H.; Fromont, J. New family and genus for Dendrilla-like sponges with characters of Verongiida. Part I Redescription of Dendrilla lacunosa Hentschel 1912, diagnosis of the new family Ernstillidae and Ernstilla n. g. Zool. Anz. 2019, 280, 14–20. [CrossRef] 39. Carter, H.J. Descriptions of Sponges from the Neighbourhood of Port Phillip Heads, South Australia, continued. Ann. Mag Nat. Hist. 1886, 18, 34–55. [CrossRef] 40. Hooper, J.; Schlacher-Hoenlinger, M. Porifera of New Caledonia. Remarks on the check list of shallow water species. In Compendium of Marine Species from New Caledonia; Documents Scientifiques et Techniques, IRD; de Forges, B.R., Payri, C.E., Eds.; Institut de Recherche Pour le Développemel: Paris, France, 2006; pp. 111–115. 41. McCauley, E.; Radjasa, O.K.; Trainato, A.; Crews, M.S.; Smith, A.; Smith, G.C.; Zerebinski, P.; Sabdono, A.; Crews, P. The UNDIP-UCSC campaign to culture chemically prolific gram-negative bacteria from Indonesian Jaspis sponges. Free Internet J. Org. Chem. 2018, IV, 123–131. [CrossRef] 42. Carvalho, M.S.; Desqueyroux-Faùndez, R.; Hajdu, E. Taxonomic notes on Poecillastra sponges (Astrophorida: Pachastrellidae), with the description of three new bathyal southeastern Pacific species. Sci. Mar. 2011, 75, 477–492. [CrossRef] 43. Kim, D.; Lee, I.S.; Jung, J.H.; Yang, S.I. Psammaplin A, a natural bromotyrosine derivative from a sponge, possesses the antibacterial activity against methicillin-resistant Staphylococcus aureus and the DNA gyrase-inhibitory activity. Arch. Pharm. Res. 1999, 22, 25–29. [CrossRef][PubMed] 44. Tabudravu, J.N.; Eijsink, V.G.; Gooday, G.W.; Jaspars, M.; Komander, D.; Legg, M.; Synstad, B.; van Aalten, D.M. Psammaplin A, a chitinase inhibitor isolated from the Fijian marine sponge Aplysinella rhax. Bioorg. Med. Chem. 2002, 10, 1123–1128. [CrossRef] 45. Jiang, Y.; Ahn, E.Y.; Ryu, S.H.; Kim, D.K.; Park, J.S.; Yoon, H.J.; You, S.; Lee, B.J.; Lee, D.S.; Jung, J.H. Cytotoxicity of psammaplin A from a two-sponge association may correlate with the inhibition of DNA replication. BMC Cancer 2004, 4, 70. [CrossRef][PubMed] 46. Kim, D.H.; Shin, J.; Kwon, H.J. Psammaplin A is a natural prodrug that inhibits class I histone deacetylase. Exp. Mol. Med. 2007, 39, 47–55. [CrossRef] 47. Piña, I.C.; Gautschi, J.T.; Wang, G.Y.; Sanders, M.L.; Schmitz, F.J.; France, D.; Cornell-Kennon, S.; Sambucetti, L.C.; Remiszewski, S.W.; Perez, L.B.; et al. Psammaplins from the sponge Pseudoceratina purpurea: Inhibition of both histone deacetylase and DNA methyltransferase. J. Org. Chem. 2003, 68, 3866–3873. [CrossRef] 48. Mora, F.D.; Jones, D.K.; Desai, P.V.; Patny, A.; Avery, M.A.; Feller, D.R.; Smillie, T.; Zhou, Y.D.; Nagle, D.G. Bioassay for the identification of natural product-based activators of peroxisome proliferator-activated receptor-γ (PPARγ): The marine sponge metabolite psammaplin A activates PPARγ and induces apoptosis in human breast tumor cells. J. Nat. Prod. 2006, 69, 547–552. [CrossRef] 49. Baud, M.G.; Leiser, T.; Haus, P.; Samlal, S.; Wong, A.C.; Wood, R.J.; Petrucci, V.; Gunaratnam, M.; Hughes, S.M.; Buluwela, L.; et al. Defining the mechanism of action and enzymatic selectivity of psammaplin A against its epigenetic targets. J. Med. Chem. 2012, 55, 1731–1750. [CrossRef] 50. Zhou, Y.-D.; Li, J.; Du, L.; Mahdi, F.; Le, T.P.; Chen, W.-L.; Swanson, S.M.; Watabe, K.; Nagle, D.G. Biochemical and Anti-Triple Negative Metastatic Breast Tumor Cell Properties of Psammaplins. Mar. Drugs 2018, 16, 442. [CrossRef] 51. Ahn, M.Y.; Jung, J.H.; Na, Y.J.; Kim, H.S. A natural histone deacetylase inhibitor, Psammaplin A, induces cell cycle arrest and apoptosis in human endometrial cancer cells. Gynecol. Oncol. 2008, 108, 27–33. [CrossRef] 52. Mujumdar, P.; Teruya, K.; Tonissen, K.F.; Vullo, D.; Supuran, C.T.; Peat, T.S.; Poulsen, S.A. An Unusual Natural Product Primary Sulfonamide: Synthesis, Carbonic Anhydrase Inhibition, and Protein X-ray Structures of Psammaplin, C. J. Med. Chem. 2016, 59, 5462–5470. [CrossRef] 53. Salaroglio, I.C.; Mujumdar, P.; Annovazzi, L.; Kopecka, J.; Mellai, M.; Schiffer, D.; Poulsen, S.A.; Riganti, C. Carbonic Anhydrase XII Inhibitors Overcome P-Glycoprotein-Mediated Resistance to Temozolomide in Glioblastoma. Mol. Cancer Ther. 2018, 17, 2598–2609. [CrossRef][PubMed] 54. Mujumdar, P.; Kopecka, J.; Bua, S.; Supuran, C.T.; Riganti, C.; Poulsen, S.A. Carbonic Anhydrase XII Inhibitors Overcome Temozolomide Resistance in Glioblastoma. J. Med. Chem. 2019, 62, 4174–4192. [CrossRef][PubMed] 55. Ratovitski, E.A. Tumor Protein (TP)-p53 Members as Regulators of Autophagy in Tumor Cells upon Marine Drug Exposure. Mar. Drugs 2016, 14, 154. [CrossRef][PubMed] Biology 2020, 9, 429 23 of 24

56. Byun, W.S.; Kim, W.K.; Han, H.J.; Chung, H.J.; Jang, K.; Kim, H.S.; Kim, S.; Kim, D.; Bae, E.S.; Park, S.; et al. Targeting Histone Methyltransferase DOT1L by a Novel Psammaplin A Analog Inhibits Growth and Metastasis of Triple-Negative Breast Cancer. Mol. Ther. Oncolytics 2019, 15, 140–152. [CrossRef][PubMed] 57. Ilan, M.; Gugel, J.; Van Soest, R.W.M. Taxonomy, reproduction and ecology of new and known Red Sea sponges. Sarsia 2004, 89, 388–410. [CrossRef] 58. Takada, K.; Imae, Y.; Ise, Y.; Ohtsuka, S.; Ito, A.; Okada, S.; Yoshida, M.; Matsunaga, S. Yakushinamides, Polyoxygenated Fatty Acid Amides That Inhibit HDACs and SIRTs, from the Marine Sponge Theonella swinhoei. J. Nat. Prod. 2016, 79, 2384–2390. [CrossRef] 59. Marra, M.V.; Bertolino, M.; Pansini, M.; Giacobbe, S.; Manconi, R.; Pronzato, R. Long-term turnover of the sponge fauna in Faro Lake (North-East Sicily, Mediterranean Sea). Ital. J. Zool. 2016, 83, 579–588. [CrossRef] 60. Picton, B.E.; Morrow, C.C. Halichondria Panicea (Pallas, 1766). [In] Encyclopedia of Marine Life of Britain and Ireland. 2016. Available online: http://www.habitas.org.uk/marinelife/species.asp?item=C4840 (accessed on 2 October 2020). 61. Ereskovsky, A.; Kovtun, O.A.; Pronin, K.K.; Apostolov, A.; Erpenbeck, D.; Ivanenko, V. Sponge community of the western Black Sea shallow water caves: Diversity and spatial distribution. PeerJ 2018, 6, e4596. [CrossRef] 62. Nakamura, F.; Kudo, N.; Tomachi, Y.; Nakata, A.; Takemoto, M.; Ito, A.; Tabei, H.; Arai, D.; de Voogd, N.; Yoshida, M.; et al. Halistanol sulfates I and J, new SIRT1-3 inhibitory steroid sulfates from a marine sponge of the genus Halichondria. J. Antibiot. (Tokyo) 2018, 71, 273–278. [CrossRef] 63. Van Soest, R.W.M.; Beglinger, E.J.; De Voogd, N.J. Mycale species (Porifera: Poecilosclerida) of Northwest Africa and the Macaronesian Islands. Zool. Med. Leiden 2014, 88, 60–109. 64. Tanita, S.; Hoshino, T. The Demospongiae of Sagami Bay. In Biological Laboratory Imperial Household; Hoikusha Publishing Co. Ltd.: Japan, Osaka, 1989; Volume i–xiii, pp. 1–197. 65. Nakao, Y.; Yoshida, S.; Matsunaga, S.; Shindoh, N.; Terada, Y.; Nagai, K.; Yamashita, J.K.; Ganesan, A.; van Soest, R.W.; Fusetani, N. Azumamides A-E: Histone deacetylase inhibitory cyclic tetrapeptides from the marine sponge Mycale izuensis. Angew. Chem. Int. Ed. Engl. 2006, 45, 7553–7557. [CrossRef][PubMed] 66. Wen, S.; Carey, K.L.; Nakao, Y.; Fusetani, N.; Packham, G.; Ganesan, A. Total synthesis of azumamide A and azumamide E, evaluation as histone deacetylase inhibitors, and design of a more potent analogue. Org. Lett. 2007, 9, 1105–1108. [CrossRef][PubMed] 67. Maulucci, N.; Chini, M.G.; Micco, S.D.; Izzo, I.; Cafaro, E.; Russo, A.; Gallinari, P.; Paolini, C.; Nardi, M.C.; Casapullo, A.; et al. Molecular insights into azumamide e histone deacetylases inhibitory activity. J. Am. Chem. Soc. 2007, 129, 3007–3012. [CrossRef][PubMed] 68. Nakao, Y.; Narazaki, G.; Hoshino, T.; Maeda, S.; Yoshida, M.; Maejima, H.; Yamashita, J.K. Evaluation of antiangiogenic activity of azumamides by the in vitro vascular organization model using mouse induced pluripotent stem (iPS) cells. Bioorg. Med. Chem. Lett. 2008, 18, 2982–2984. [CrossRef] 69. Villadsen, J.S.; Stephansen, H.M.; Maolanon, A.R.; Harris, P.; Olsen, C.A. Total synthesis and full histone deacetylase inhibitory profiling of Azumamides A-E as well as β2-epi-Azumamide E and β3-epi-Azumamide, E. J. Med. Chem. 2013, 56, 6512–6520. [CrossRef] 70. Maolanon, A.R.; Villadsen, J.S.; Christensen, N.J.; Hoeck, C.; Friis, T.; Harris, P.; Gotfredsen, C.H.; Fristrup, P.; Olsen, C.A. Methyl effect in azumamides provides insight into histone deacetylase inhibition by macrocycles. J. Med. Chem. 2014, 57, 9644–9657. [CrossRef] 71. De Weerdt, W.H. Family Chalinidae Gray, 1867. In Systema Porifera: A Guide to the Classification of Sponges; Hooper, J.N.A., Van Soest, R.W.M., Eds.; Kluwer Academic/Plenum Publishers: New York, NY, USA, 2002; pp. 852–873. 72. Lakwal, V.R.; Kharate, D.S.; Mokashe, S.S. Diversity and distribution of intertidal marine sponges from Ratnagiri coast of Arabian Sea, (M.S.) India. Flora Fauna 2018, 24, 207–216. 73. Muller, Y. Faune et flore du littoral du Nord, du Pas-de-Calais et de la Belgique: Inventaire. [Coastal fauna and flora of the Nord, Pas-de-Calais and Belgium: Inventory]. In Commission Régionale de Biologie Région Nord Pas-de-Calais: France; Christopher Helm: London, UK, 2004; p. 307. 74. Bakus, G.J.; Nishiyama, G.K. Three species of toxic sponges from Cebu, Philippines (Porifera: Demospongiae). Proc. Biol. Soc. Wash 2000, 113, 1162–1172. 75. Granito, R.G.; Custódio, M.R.; Rennó, A.C.M. Natural marine sponges for bone tissue engineering: The state of art and future perspective. J. Biomed. Mater. Res. B 2017, 105, 1717–1727. [CrossRef] Biology 2020, 9, 429 24 of 24

76. Röthig, T.; Voolstra, C.R. Xestospongia testudinaria nighttime mass spawning observation in Indonesia. Galaxea J. CRS 2016, 18, 1–2. [CrossRef] 77. De Voogd, N.J.; Van Soest, R.W.M. Indonesian sponges of the genus Petrosia Vosmaer (Demospongia: Haplosclerida). Zool. Med. Leiden 2002, 76, 193–209. 78. Oku, N.; Nagai, K.; Shindoh, N.; Terada, Y.; van Soest, R.W.; Matsunaga, S.; Fusetani, N. Three new cyclostellettamines, which inhibit histone deacetylase, from a marine sponge of the genus Xestospongia. Bioorg Med. Chem. Lett. 2004, 14, 2617–2620. [CrossRef][PubMed] 79. Lee, Y.; Jang, K.H.; Jeon, J.-E.; Yang, W.-Y.; Sim, C.J.; Oh, K.-B.; Shin, J. Cyclic Bis-1,3-dialkylpyridiniums from the Sponge Haliclona sp. Mar. Drugs 2012, 10, 2126–2137. [CrossRef][PubMed] 80. Shih, S.-P.; Lee, M.-G.; El-Shazly, M.; Juan, Y.-S.; Wen, Z.-H.; Du, Y.-C.; Su, J.-H.; Sung, P.-J.; Chen, Y.-C.; Yang, J.-C.; et al. Tackling the Cytotoxic Effect of a Marine Polycyclic Quinone-Type Metabolite: Halenaquinone Induces Molt 4 Cells Apoptosis via Oxidative Stress Combined with the Inhibition of HDAC and Topoisomerase Activities. Mar. Drugs 2015, 13, 3132–3153. [CrossRef][PubMed] 81. Takaku, M.; Kainuma, T.; Ishida-Takaku, T.; Ishigami, S.; Suzuki, H.; Tashiro, S.; van Soest, R.W.; Nakao, Y.; Kurumizaka, H. Halenaquinone, a chemical compound that specifically inhibits the secondary DNA binding of RAD51. Genes Cells 2011, 16, 427–436. [CrossRef][PubMed] 82. Tsukamoto, S.; Takeuchi, T.; Kawabata, T.; Kato, H.; Yamakuma, M.; Matsuo, K.; El-Desoky, A.H.; Losung, F.; Mangindaan, R.E.; de Voogd, N.J.; et al. Halenaquinone inhibits RANKL-induced osteoclastogenesis. Bioorg. Med. Chem. Lett. 2014, 24, 5315–5317. [CrossRef] 83. Liu, R.; Liu, J.Y. Checklist of Marine Biota of China Seas; China Science Press: Beijing, China, 2008; p. 1267. 84. Janes, M.P.; Mary, A.G. Synopsis of the Family Xeniidae (Cnidaria: Octocorallia): Status and Trends. In Proceedings of the 12th International Coral Reef Symposium, Cairns, Australia, 9–13 July 2012. 85. Andrianasolo, E.H.; Haramaty, L.; White, E.; Lutz, R.; Falkowski, P. Mode of action of diterpene and characterization of related metabolites from the soft coral, Xenia elongata. Mar. Drugs 2014, 12, 1102–1115. [CrossRef] 86. Donovan, S. Scanning Em study of the living cyrtocrinid Holopus rangii (Echinodermata, Crinoidea) and implications for its functional morphology. J. Paleontol. 1992, 66, 665–675. [CrossRef] 87. Kemami Wangun, H.V.; Wood, A.; Fiorilla, C.; Reed, J.K.; McCarthy, P.J.; Wright, A.E. Gymnochromes E and F, cytotoxic phenanthroperylenequinones from a deep-water crinoid, Holopus rangii. J. Nat. Prod. 2010, 73, 712–715. [CrossRef] 88. Carroll, A.R.; Copp, B.R.; Davis, R.A.; Keyzers, R.A.; Prinsep, M.R. Marine natural products. Nat. Prod. Rep. 2020, 37, 175–223. [CrossRef] 89. Li, S.; Yao, H.; Xu, J.; Jiang, S. Synthetic routes and biological evaluation of largazole and its analogues as potent histone deacetylase inhibitors. Molecules 2011, 16, 4681–4694. [CrossRef][PubMed] 90. Varghese, T.A.; Jayasri, M.A.; Suthindhiran, K. Marine Actinomycetes as potential source for histone deacetylase inhibitors and epigenetic modulation. Lett. Appl. Microbiol. 2015, 61, 69–76. [CrossRef][PubMed] 91. Houssen, W.E.; Jaspars, M. 4-Hydroxybenzoyl derivative from the aqueous extract of the hydroid Campanularia sp. J. Nat. Prod. 2005, 68, 453–455. [CrossRef][PubMed]

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).