CCN Workshop Element, in the Ccn2 Promoter

EDITORIAL 463

CCN workshop element, in the ccn2 promoter. J Clin Pathol: first published as 10.1136/jcp.2005.025759 on 27 April 2005. Downloaded from ...... P Trackman (USA) reported that pros- taglandin E2 (PGE2) inhibited TGFb induced CCN2 production in IMR-90 CCN workshop cells via p42/p44 mitogen activated protein kinase, yet in gingival fibroblasts D Brigstock, L Lau, B Perbal ccn2 expression was less sensitive to inhibition by PGE2 as a result of a p38 ...... mitogen activated protein kinase mechanism. These data may explain Report on the Third International Workshop on the CCN Family of why fibrotic gingival outgrowths over- Genes express TGFb and CCN2 in the presence of PGE2. Overall, these presentations highlighted how variations in tissue he CCN family currently comprises stabilisation, the latter of which was microenvironment can have important six extracellular matrix associated attributed to a novel regulatory element effects on ccn2 expression. Tproteins (CCN1–6) that regulate in the 39-untranslated region of the diverse cell functions. Although CCN chick ccn2 gene, which is distinct from RECEPTORS/SIGNALLING molecules regulate vital processes in ones found in mouse or human ccn2 In the past few years, cell surface vivo (for example, chondrogenesis, genes. In addition to promoting chon- integrins have emerged as signalling angiogenesis, and matrix remodelling) drogenesis, ccn2 is expressed by breast receptors for CCN proteins. L Lau and are associated with several patho- cancer cells and may be involved in their (USA) showed that integrins avb3 and physiological disorders (such as fibrosis metastasis to bone. In studies designed a6b1 mediate the distinct functions of and tumorigenesis), it has been a to address aspects of gene regulation in CCN1 in mesenchymal cells, and identi- challenge to define the underlying bio- these scenarios, T Eguchi (Japan) fied specific binding sites for each logical mechanisms involved. Progress reported that ccn2 expression is princi- integrin. Moreover, CCN1 mutant pro- has been hampered by the disparate in pally activated by cis-elements, includ- teins disrupted at specific integrin bind- vivo and in vitro models used by ing TRENDIC (transcription enhancer ing sites block CCN1 functions mediated investigators in the field, and by the dominant in chondrocytes) in the through the cognate integrins. difficulty in obtaining validated human HCS-2/8 chondrocyte cell line, D Brigstock (USA) showed that in reagents (particularly recombinant whereas it is mainly Smad regulated in hepatic or pancreatic stellate cells, CCN proteins) for experimental use. In MDA231 breast cancer cells. CCN2 stimulated adhesion, migration, spite of these drawbacks, there have or gene expression involved interactions been many exciting developments in the of integrin avb3 or integrin a5b1, ‘‘Variations in tissue microenviron- field over the past few years, and it was respectively, with discrete novel regions against this backdrop that investigators ment can have important effects on in module 4 of the CCN2 protein. A convened for the Third International ccn2 expression’’ Leask (UK) showed that endogenous Workshop on the CCN Family of Genes CCN2 facilitates fibroblast spreading on in St Malo, France on 20–23 October Another major property of CCN2 is as fibronectin substrate through its ability http://jcp.bmj.com/ 2004. a stimulator of fibrogenic pathways, and to bind directly to fibronectin, integrins, much attention has previously focused and synedcan 4, suggesting that CCN2 on its action as a downstream mediator GENE EXPRESSION may function principally by regulating of transforming growth factor b (TGFb) Although studies in the early 1990s receptor–ligand interactions. showed that CCN1 and CCN2 were through Smad dependent pathways. Although many of the biological encoded by immediate early genes, Nonetheless, additional mechanisms of properties of the CCN proteins are current research in the field highlights regulating ccn2 expression have been attributable to their interactions with on September 29, 2021 by guest. Protected copyright. the diverse mechanisms that influence identified using cells from fibrotic integrins and heparin sulfate proteogly- the regulation of CCN gene expression. lesions as compared with their normal cans, other lines of investigation were M Goppelt-Struebe (Germany) reported counterparts. V Haydont (France) reported that may help to define addi- that CCN2 expression in endothelial reported that, in smooth muscle cells tional receptor molecules. Potentially cells or fibroblasts is inhibited by mono- from radiation enteritis, pharmacologi- promising approaches included the meric G actin, but it is stimulated by cal inhibitors of the Rho/Rock pathway yeast two hybrid system for CCN1 F actin stress fibres, emphasising the were effective, at early time points, in discussed by P Robertson (USA) and importance of changes in cell morphol- blocking expression of ccn2 but not of CCN2 crosslinking to mesangial cells ogy as a determinant of CCN2 produc- TGFb or collagen. G Yang (USA) reported by N Wahab (UK). tion. R O’Leary (Ireland) reported the reported that basal or serum stimulated downregulation and disassembly of sev- expression of ccn2 is more exaggerated DIFFERENTIATION AND eral cytoskeletal proteins in human in keloid fibroblasts than in normal DEVELOPMENT glomerular mesangial cells in response fibroblasts. Although Smads were Several CCN proteins have been recog- to CCN2, suggesting that actin reorga- involved in both cell types, raised ccn2 nised as major regulators of skeletal nisation is among the pathophysiologi- expression by keloid fibroblasts was development. M Takigawa (Japan) cal effects of CCN2 in diabetic associated with increased activation of reported a role for CCN2 in cartilage nephropathy. AP-1 and c-Jun. X. Shi-wen (UK) repair and osteogenesis, proposed that CCN2 is a well characterised regulator reported that endothelin 1, which is mesenchymal cell differentiation in of chondrogenesis and S Kubota raised in fibrotic diseases including wounded vascularised tissues may be (Japan) reported that CCN2 expres- those of the lung, stimulated ccn2 promoted by CCN2 from platelets, and sion was enhanced during chick chon- expression in lung fibroblasts via Erk1/ showed differential biological activities drocyte differentiation as a result of 2 and transcriptional activation of the of the individual modules of CCN2. enhanced gene transcription and mRNA BCE-1 element, but not the Smad L Dornbach (USA) showed that ccn1

www.jclinpath.com 464 EDITORIAL null mice that survive to birth exhibit a fibrotic disorder that is strongly (Canada) presented results establishing skeletal abnormalities involving the associated with overexpression of ccn2. that CCN3 physically interacts with the J Clin Pathol: first published as 10.1136/jcp.2005.025759 on 27 April 2005. Downloaded from radius, ribs, sternum, and vertebrae. S Twigg (Australia) reported that CCN2 C-terminus of Connexin 43 (Cx43). This Importantly, some skeletal defects were contributes to high glucose induced observation provides a possible explana- more exacerbated in mice that were null matrix production by increasing the tion for the association between Cx43 for both ccn2 and ccn1 than in those expression of TIMP-1 and thus decreas- expression and reduced tumorigenicity, that were null for ccn2 or ccn1 alone, ing the rate of matrix breakdown. because expression of full length CCN3 suggesting that these molecules have B Riser (USA) showed that urinary correlates with a growth suppressed both interacting and independent func- CCN2 concentrations assessed by phenotype in several cell systems tions in regulating skeletal develop- enzyme linked immunoabsorbent assay including glioblastoma, choriocarci- ment. P Francis-West (UK) reported were increased six to sevenfold in an noma, and Ewing sarcoma. In growth that ccn4 and ccn6 are expressed in animal model of diabetic nephropathy suppressed glioblastoma cells, Cx43 and the joints and chondrocytes of the and in human subjects with diabetes CCN3 were shown to colocalise at the developing chick long bones and in and renal disease. Some individuals plasma membrane. differentiating ATDC5 cells, in which with diabetes but without renal disease they act downstream of b catenin but had raised CCN2 concentrations, ‘‘P Koeffler presented results con- have opposing effects on matrix produc- although longitudinal studies to exam- firming that CCN proteins can tion. Based on transfection studies and a ine whether this is predictive of diabetic indeed act either as oncogenes or fracture repair model, L Desnoyers nephropathy have yet to be conducted. tumour suppressors, depending (USA) showed that CCN4 acts to pro- Urinary CCN2 from most diseased mote mesenchymal cell proliferation patients comprised intact 38 kDa CCN2 upon the type of cancer considered’’ and osteoblastic differentiation yet in addition to unidentified 12 kDa and represses chondrocyte differentiation. 200 kDa moieties. Because urinary R Lupu (USA) reported that expres- Data presented by K Katsube (Japan) CCN2 may reflect a failure of resorption sion of ccn1 in MCF7 breast cancer cells showed that in the Kusa bone marrow and/or local production in the kidney, results in upregulation of the CCN1 derived stem cell line, ccn3 expression examination of circulating CCN2 may receptor integrin avb3, which in turn was upregulated by Notch, which is be more appropriate. To this end, promotes breast cancer cell prolifera- associated with the ability of the cells to R Goldschmeding (the Netherlands) tion, survival, and Taxol resistance. follow a neurogenic rather than osteo- reported that plasma CCN2 values in P Koeffler (USA) presented results con- genic pathway. These results suggest patents with diabetic nephropathy were firming that CCN proteins can indeed that CCN3 may mediate specific Notch raised and correlated with plasma crea- act either as oncogenes or tumour dependent cell lineage development. tinine concentrations and albuminuria. suppressors, depending upon the type Effects of CCN3 on gene expression CCN5 inhibits the proliferation of cancer considered. For example, the were further discussed by N Planque and motility of smooth muscle cells. expression of ccn1 in cancer cells of the (France), who showed that module 4 of J Castellot (USA) reported that CCN5 is breast, brain, and ovary promotes their CCN3 has DNA and nuclear binding widely expressed in many embryonic growth in vitro and tumorigenicity in activity, and that this property is respon- and adult tissues, but that values are immunodeficient mice. In contrast, sible for the association of CCN3 with low at sites of smooth muscle cell overexpression of ccn1 inhibits the the nucleus and its regulation of gene hyperplasia, such as leiomyomas or growth of endometrial or lung cancer http://jcp.bmj.com/ transcription. restenosis. Preliminary data using Ad- cells. Divergent proproliferative and CCN5 suggest that CCN5 may have antiproliferative effects of CCN1 were therapeutic benefit in the treatment of suggested to involve a balance between PATHOBIOLOGY smooth muscle cell proliferative disor- b catenin induced stimulation of p53 via Studies of CCN2 in fibrotic diseases ders. c-myc and integrin linked kinase (ILK) continue to be a major research focus inhibition of p53. of many investigators. E Brandan

(Chile) reported that ccn2 was over- TUMORIGENESIS on September 29, 2021 by guest. Protected copyright. expressed in the fibrotic mdx mouse Since the discovery of CCN3 as an CONCLUSIONS AND model of Duchene muscular dystrophy antiproliferative protein whose trunca- PERSPECTIVES and that in C2C12 mouse myofibro- tion reveals oncogenic potential, a grow- Most of the data presented at this blasts, ccn2 was induced by TGFb or ing body of evidence supports the excellent meeting confirms the major lysophophatidic acid and, when added concept that alterations of CCN protein involvement of CCN proteins in funda- exogenously, promoted cell differentia- structure or expression are associated mental biological processes. As dis- tion and proteoglycan synthesis, in with cancer development. The first cussed by B Perbal (France), the addition to complexing with proteogly- evidence for CCN3 being involved in variety of functions attributed to the cans such as decorin. S Ahmed non-solid tumorigenesis was presented CCN proteins makes them resemble an (Norway) showed that, in a model of by L Gilmour (Ireland), who reported intriguing group of ‘‘moonlighting pro- lung fibrosis secondary to cardiac that ccn3 is downregulated in human teins’’, which play distinct roles in ischaemia, ccn2 was overexpressed in chronic myeloid leukaemia (CML) cell various biological contexts. Many com- the lung and attributed to production by lines and primary CML cells compared plicated signalling networks governing endothelial cells and macrophages. In a with normal bone marrow cells. In CML cell fate and biology are interconnected study of atherosclerosis by I Cicha cells, ccn3 expression is regulated by the via a relatively small number of regula- (Germany), CCN2 protein concentra- Bcr–Abl kinase. The reduced concentra- tory proteins. A fascinating aspect of tions were greatly increased in lipid rich tions of CCN3 in patients with CML signalling regulation and cell commu- plaques compared with fibrous plaques, were in agreement with high expression nication centres around understanding and it was suggested that it acts as a of the Bcr–Abl kinase. Interestingly, how limited numbers of similar or monocyte chemoattractant in diseased patients undergoing remission showed identical regulators are assembled in tissue. recovery of normal CCN3 expression. different ways to provide combinatorial Diabetic nephropathy is an important Adding to the variety of proteins with events that permit the control of cellular cause of morbidity and mortality and is which CCN3 combines, C Naus responses to complex environments. The

www.jclinpath.com EDITORIAL 465 variety of biological functions assigned Nationale Contre le Cancer (Comite´du Cher), L Lau, Department of Biochemistry and to the CCN proteins, together with their AMGEN, GENENTECH, BAXTER, le Conseil Molecular Genetics, University of Illinois J Clin Pathol: first published as 10.1136/jcp.2005.025759 on 27 April 2005. Downloaded from multiple sites of action, highlight them Geńe´ral d’Ille et Vilaine, Munin Corporation, Colleage of Medicine, Chicago, IL 60607, Novus Biologicals, the International CCN as potential key factors in the assembly USA Society, and BioMed Central. B Perbal, Laboratoire d’Oncologie Virale et of integrative circuitry needed for effi- Molećulaire - UFR de Biochimie, Universite´ J Clin Pathol 2005;58:463–465. cient cellular crosstalk and the adapta- Paris 7 - D. Diderot, 2 Place Jussieu 75005 doi: 10.1136/jcp.2005.025759 tion of living organisms to their Paris, France surrounding medium...... Correspondence to: Professor B Perbal, Authors’ affiliations Laboratoire d’Oncologie Virale et Molećulaire - ACKNOWLEDGEMENTS D Brigstock, Center for Cell and Vascular UFR de Biochimie, Universite´Paris 7 - D. The third international workshop on the CCN Biology, Children’s Research Institute, Diderot, 2 Place Jussieu 75005 Paris, France; family of genes was sponsored by: La Ligue Columbus, Ohio 43016, USA [email protected]

ECHO ...... Study clarifies PCR results for viral CNS infections he diagnostic value of PCR assay for viral infections of the CNS will be improved now that a study has identified factors affecting test performance. T The positive predictive value was only 54% for infections judged clinically as likely CNS infections versus possible or unlikely infections when multiplex PCR results for various viral nucleic acids in patients’ CSF were matched with illness episodes. Twenty seven CSF Please visit the Journal of samples for possible or unlikely CNS infections were positive for Epstein Barr virus. Most Clinical samples from episodes most likely to be CNS infections were positive for herpes simplex Pathology virus (HSV) and enterovirus. The negative predictive value was 83%, meaning that negative website [www. results can be interpreted as discounting viral infection with only moderate confidence. CSF jclinpath.com] samples obtained between three and 14 days after onset of neurological symptoms had the for a link to the full text of this best chance of detecting viruses, as did those in which white cell count was raised. article. PCR tests were done on 787 frozen samples collected over four years in a teaching http://jcp.bmj.com/ hospital. Comparing results with episodes of possible viral CNS infections was possible for 494 episodes in 483 (66%) patients with detailed clinical data; 15% of patients were aged ,1 year and 26% up to 16 years. Each sample was tested for human herpes virus types 1–6, human polyoma virus JC, enteroviruses, and Epstein Barr virus. PCR assays have established that several known viral infections can include involvement of the CNS, but many have not been validated for CNS infections, and doctors are often unsure what positive or negative findings mean for patient management. m Davies NWS, et al. Journal of Neurology, Neurosurgery, and Psychiatry 2005;76:82–87. on September 29, 2021 by guest. Protected copyright.