title: A specific microdomain ("glycosynapse 3") controls phenotypic conversion and reversion of bladder cancer cells through GM3-mediated interaction of alpha3beta1 integrin with CD9.
abstract: Cell motility is highly dependent on the organization and function of microdomains composed of integrin, proteolipid/tetraspanin CD9, and ganglioside (Ono, M., Handa, K., Sonnino, S., Withers, D. A., Nagai, H., and Hakomori, S. (2001) Biochemistry 40, 6414-6421; Kawakami, Y., Kawakami, K., Steelant, W. F. A., Ono, M., Baek, R. C., Handa, K., Withers, D. A., and Hakomori, S. (2002) J. Biol. Chem. 277, 34349-34358), later termed "glycosynapse 3" (Hakomori, S., and Handa, K. (2002) FEBS Lett. 531, 88-92, 2002). Human bladder cancer cell lines KK47 (noninvasive and nonmetastatic) and YTS1 (highly invasive and metastatic), both derived from transitional bladder epithelia, are very similar in terms of integrin composition and levels of tetraspanin CD9. Tetraspanin CD82 is absent in both. The major difference is in the level of ganglioside GM3, which is several times higher in KK47 than in YTS1. We now report that the GM3 level reflects glycosynapse function as follows: (i) a stronger interaction of integrin alpha3 with CD9 in KK47 than in YTS1; (ii) conversion of benign, low motility KK47 to invasive, high motility cells by depletion of GM3 by P4 (D-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol) treatment or by knockdown of CD9 by the RNA interference method; (iii) reversion of high motility YTS1 to low motility phenotype like that of KK47 by exogenous GM3 addition, whereby the alpha3-to-CD9 interaction was enhanced; (iv) low GM3 level activated c-Src in YTS1 or in P4-treated KK47, and high GM3 level by exogenous addition caused Csk translocation into glycosynapse, with subsequent inhibition of c-Src activation; (v) inhibition of c-Src by "PP2" in YTS1 greatly reduced cell motility. Thus, GM3 in glycosynapse 3 plays a dual role in defining glycosynapse 3 function. One is by modulating the interaction of alpha3 with CD9; the other is by activating or inhibiting the c-Src activity, possibly through Csk translocation. High GM3 level decreases tumor cell motility/invasiveness, whereas low GM3 level enhances tumor cell motility/invasiveness. Oncogenic transformation and its reversion can be explained through the difference in glycosynapse organization.
authors.affiliation: Pacific Northwest Research Institute, Seattle, Washington 98122, USA.
authors.forename: Koji
authors.initials: K
authors.lastname: Mitsuzuka
authors.forename: Kazuko
authors.initials: K
authors.lastname: Handa
authors.forename: Makoto
authors.initials: M
authors.lastname: Satoh
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Arai
authors.forename: Senitiroh
authors.initials: S
authors.lastname: Hakomori
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis* / Q000378:metabolism; D015153:Blotting, Western; D000081247:CSK Tyrosine-Protein Kinase; D045744:Cell Line, Tumor; D002465:Cell Movement; D002471:Cell Transformation, Neoplastic; D047369:Chromatin Immunoprecipitation; D002855:Chromatography, Thin Layer; D004591:Electrophoresis, Polyacrylamide Gel; D005679:G(M3) Ganglioside / Q000378:metabolism*; D005732:Gangliosides / Q000737:chemistry; D006801:Humans; D039422:Integrin alpha3 / Q000378:metabolism; D039201:Integrin alpha3beta1 / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism; D051861:Kangai-1 Protein / Q000096:biosynthesis; D008024:Ligands; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000378:metabolism; D018613:Microscopy, Confocal; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010641:Phenotype; D010770:Phosphotransferases / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D034622:RNA Interference; D013569:Synapses; D060245:Tetraspanin 29; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000473:pathology*; D019061:src-Family Kinases
chemical_list: D015703:Antigens, CD; C554869:CD9 protein, human; D005679:G(M3) Ganglioside; D005732:Gangliosides; D039422:Integrin alpha3; D039201:Integrin alpha3beta1; D016023:Integrins; D051861:Kangai-1 Protein; D008024:Ligands; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D060245:Tetraspanin 29; D010770:Phosphotransferases; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human