November 28 PROGRAM 04 Glycoscience : diversity and integration

Regulation of hyaluronan synthesis and its importance for tissue remodeling and cancer

Markku I. Tammi, M.D., Ph.D. Professor, Institute of Biomedicine, School of Medicine, University of Eastern Finland, FINLAND Markku I. Tammi Hyaluronan is a multimillion molecular UDP-GlcNAc content and consequent Profile mass, linear, non-sulfated glycosami- O-GlcNAc-signaling (Figure 1) 4)5). Markku Tammi is a cell biologist who has noglycan with a repeating structure of worked on proteoglycans, lately on hyal- 5) uronan and its involvement in disease. He [β1->3GlcNAc -β1->4GlcUA]. It is not Besides influencingHas2 expression , obtained M.D. in the University of Turku attached to a core protein, but is synthe- UDP-GlcNAc content and O-GlcNAc- in 1975, followed by Ph.D. in 1979 with a sized as a free chain that runs out of the signaling have also more direct effects on thesis entitled “Arterial Glycosaminogly- cell through a pore in plasma membrane, HAS2 activity and hyaluronan synthesis. cans in Atherogenesis”. After dissertation, the pore formed by hyaluronan As a HAS substrate UDP-GlcNAc can until 1994, he worked with Prof. Heikki Helminen in the University of Kuopio on (HAS1-3), the that construct either stimulate or inhibit hyaluronan proteoglycans of articular cartilage, espe- this polysaccharide using cytosolic UDP- synthesis, according to its cellular con- cially their response to joint loading. Dur- sugars as substrates 1). This unique way of tent 4). In addition, HAS2 itself contains ing 1984-1986 he made a postdoctoral fel- secretion results in a cell surface glyco- O-GlcNAc-moieties, which increase the lowship in the University of California in calyx, several micrometers thick 2)3), and stability or enzymatic activity of HAS pro- Berkeley, studying yeast glycoproteins with Fig.1 Prof. Clinton Ballou. In 1994-1996 he eventual release of hyaluronan into extra- tein ( ). Furthermore, especially UDP- joined, together with his wife Raija Tammi, cellular space where it organizes the matrix Glc secreted or leaked from cells stimulate M.D. Ph.D, Dr. Vincent Hascall’s laborato- by aggregating with specific proteoglycans Has2 expression by activating a G-protein ry in Lerner Research Institute, Cleveland, and forming transient cross-links with coupled UDP-sugar receptor. Thus, glu- to establish a new organotypic model for other matrix proteins. cose and its UDP-sugar metabolites are research on hyaluronan metabolism and strongly involved in the regulation of hyal- functions in skin epidermis. After return- ing to Kuopio, the work was continued to Besides a lubricant and space filler between uronan synthesis at multiple levels. show that hyaluronan as a major epidermal the cells and fibrous matrix components, We have shown that hyaluronan accumu- matrix molecule is strongly involved in ke- hyaluronan has been recognized as an lation in malignant tumors like breast, ratinocyte migration, proliferation and dif- important signaling molecule, governing prostate, gastric, colon and ovarian can- ferentiation, and epidermal wound heal- Figure 1. Multiple roles of UDP-GlcNAc in hyaluronan synthesis. processes like cell migration, proliferation, cers is an unfavourable prognostic factor 1. As a substrate of HAS UDP-GlcNAc concentration has a direct influence on the rate of hyaluronan synthesis. ing. During the last 15 years, collaborating 6) with local clinicians, they have also dem- inflammation, and malignant growth. In for patient survival . Immunohistochemi- 2. With UDP-GlcNAc abundance, HAS serine/threonine residues are subject to modification byO -GlcNAc, mediated by OGT and resulting onstrated that hyaluronan accumulates in general, whenever tissues undergo remod- cal and real-time RT-PCR analyses of the in enhanced enzymatic activity of HAS. certain cancers and forms a strong risk fac- eling, whether it be embyonic develop- HAS enzymes done in breast, ovarian and 3. The cellular content of UDP-GlcNAc influences the level O-GlcNAc modifications in the transcription factors SP1 and YY1, which in tor for unfavourable prognosis. Currently, ment, , or cancer, hyaluro- endometrial cancers have not revealed turn control Has2 . The cellular content of UDP-GlcNAc is increased by feeding cells with glucose or even more with his major interest is in the regulation of nan synthesis is activated. Expression of unequivocal correlation with hyaluronan glucosamine, and decreased by mannose. UDP-GlcNAc is synthesized in cytosol, where it is used for hyaluronan synthesis and O-GlcNAc hyaluronan synthesis, both at transcrip- the three Has are subject to regula- content, suggesting that mechanisms other modifications by OGT. Golgi membrane transporters are expected to maintain a high levels of UDP-sugars in this compartment despite tional and posttranslational levels, and concentration fluctuations in the cytosol. possibilities to use this information for di- tion by multiple stimuli, like growth fac- than gene expression are also involved. We agnostic and therapeutic use. The work has tors, cytokines, prostaglandings, and hor- are currently exploring the possibility that resulted in a discovery of the key role of mones 1). the aerobic glycolysis typical for cancer cellular UDP-GlcNAc concentration as a cells (Warburg effect), associated with high substrate for hyaluronan synthesis, and as As the only Has with its deletion embryon- glucose uptake, contributes to the hyal- a regulator of hyaluronan tran- scription, and a modifier of HAS ically lethal, Has2 regulation has received uronan deposits via enhanced UDP-sugar activity, the latter two via cytosolic protein most interest. Has2 promoter contains supply. Hyaluronan and its synthesis are O-GlcNAc modifications. several response elements accounting for recognized as novel targets of therapy in the influences of the inflammatory and cancer, but perhaps also in other chronic, growth promoting effectors mentioned low intensity inflammatory processes in References above 1). In addition, Has2 expression is which hyaluronan synthesis is increased, 1) Tammi RH, Passi AG, Rilla K, Karousou E, Vigetti D, Makkonen K, Tammi the cellular pool of UDP-N-Acetylhexosamines. J. Biol. Chem. (283):7666- strongly modulated by the metabolic state metabolic syndrome and arterial diseases MI. Transcriptional and posttranslational regulation of hyaluronan synthe- 7673, 2008. sis. FEBS J. (278): 1419-1428, 2011. 5) Jokela TA, Makkonen KM, Oikari S, Kärnä R, Koli E, Hart GW, Tammi RH, of the cell, mediated by AMPK activity and as examples. 2) Kultti A, Rilla K, Tiihonen R, Spicer AP, Tammi RH, Tammi MI. Hyaluro- Carlberg C, Tammi MI. Cellular content of UDP-N-Acetylhexosamines cellular glucose supply, the latter through nan synthesis induces microvillus-like cell surface protrusions. J Biol Chem controls 2 expression and correlates with O-GlcNAc (281):15821-15828, 2006. modification of transcription factors YY1 and SP1. J Biol Chem (286): 33632- 3) Rilla K, Kultti A, Tammi M, Tammi R. Pericellular hyaluronan coat visual- 33640, 2011. ized in live cells with a fluorescent probe is scaffolded by plasma membrane 6) Tammi R, Kultti A, Kosma V-M, Pirinen R, Auvinen P, Tammi M. Hyaluro- hyaluronan, glucose, protrusions. J Histochem Cytochem (56): 901-910, 2008. nan in human tumors: Pathobiological and prognostic messages from cell- Keywords 4) Jokela TA, Jauhiainen M, Auriola S, Kauhanen M, Tiihonen R, Tammi MI, associated and stromal hyaluronan. Semin Cancer Biol (18): 288-295, 2008. UDP-GlcNAc, Tammi RH. Mannose inhibits hyaluronan synthesis by downregulation of O-GlcNAc , cancer

26 the 20th Anniversary of the Mizutani Foundation for Glycoscience Commemorative Symposium 27