title: Sialylation and sulfation of lactosylceramide distinctly regulate anchorage-independent growth, apoptosis, and gene expression in 3LL Lewis lung carcinoma cells.
abstract: To investigate the significance of sialylation and sulfation of lactosylceramide in transformed cells, we established ganglioside GM3- and lactosylsulfatide (SM3)-reconstituted cells by transfecting cDNAs of GM3 synthase and cerebroside sulfotransferase into the J5 subclone of 3LL Lewis lung carcinoma cells. The J5 clone was selected for the transfection of these genes because it lacks GM3 and SM3 but accumulates lactosylceramide. The anchorage-dependent growth of both GM3- and SM3-reconstituted cells was similar. However, anchorage-independent growth (as measured by colony-forming ability in soft agar) of the SM3- reconstituted cells was almost completely lost, which supports our previous observation showing the suppression of tumorigenic potential in vivo and beta1 integrin gene expression induced by the introduction of cerebroside sulfotransferase gene (Kabayama et al. [2001] J. Biol. Chem., 276, 26777-26783). The GM3-reconstituted cells formed a significantly higher number of colonies in soft agar compared to mock-transfected cells and began to proliferate and become resistant to apoptosis when serum was depleted, indicating that endogenous GM3 is essential for maintaining these fundamental properties of malignant cells. We also found that serum-induced ERK1/2 activation was suppressed in the GM3-reconstituted cells, suggesting that anchorage-independent cell cycle initiation by endogenous GM3 is elicited through pathway(s) independent of ERK1/2 activation. The selective down-regulation of platelet-derived growth factor (PDGF)-dependent ERK1/2 activation in the GM3-reconstituted cells was due to the substantial decreases of PDGF alpha receptor mRNA and protein, but in the SM3-reconstituted cells PDGF alpha receptor expression was similar to mock cells. Thus, endogenously produced GM3 and SM3 differentially and distinctly regulate tumor-progression ability, that is, GM3 leads the transformed phenotype of J5 cells to promotion and SM3 to abrogation.
authors.affiliation: Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-jo, Nishi 6-chome, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Uemura
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kabayama
authors.forename: Mariko
authors.initials: M
authors.lastname: Noguchi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Jin-Ichi
authors.initials: J
authors.lastname: Inokuchi
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism*; D017209:Apoptosis; D018827:Carcinoma, Lewis Lung / Q000378:metabolism* / Q000473:pathology*; D002448:Cell Adhesion; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D004789:Enzyme Activation; D015972:Gene Expression Regulation, Neoplastic; D007129:Immunoglobulin Gm Allotypes / Q000378:metabolism; D019012:Integrin beta1 / Q000235:genetics; D007790:Lactosylceramides / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics; D013431:Sulfates / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D007129:Immunoglobulin Gm Allotypes; D019012:Integrin beta1; D007790:Lactosylceramides; D010982:Platelet-Derived Growth Factor; D013431:Sulfates; C009744:CDw17 antigen; D020796:Receptor, Platelet-Derived Growth Factor alpha; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D019158:N-Acetylneuraminic Acid