title: GM1 / GD1b / GA1 synthase expression results in the reduced cancer phenotypes with modulation of composition and raft-localization of gangliosides in a melanoma cell line.
abstract: Gangliosides are expressed in neuroectoderm-derived tumors, and seemed to play roles in the regulation of cancer properties. To examine the behavior and roles of individual gangliosides, GM1/GD1b/GA1 synthase cDNA was introduced into the melanoma cell line SK-MEL-37, and changes in tumor phenotypes were analyzed. The transfectant cells showed neo-expression of GD1b, GT1b, and GM1, and reduced expression of GM3, GM2, GD2, and GD3. Function analyses revealed that the transfectant cells had definite reduction in cell growth and invasion. Tyrosine-phosphorylation levels of proteins such as p130Cas and paxillin were also reduced in the transfectants. These results suggested that the expression of GM1/GD1b/GA1 synthase resulted in the suppression of tumor properties. In the analyses of the floating patterns of gangliosides using fractions from sucrose density gradient ultracentrifugation of TritonX-100 extracts, the majority of gangliosides were found in glycolipid-enriched microdomain (GEM)/raft fractions, while GD3, GD1b, and GT1b in the transfectant cells tended to disperse to non-GEM/raft fractions. Furthermore, GD3, GD1b, and GT1b in non-GEM/raft dominantly had unsaturated fatty acids, while those in GEM/rafts contained more saturated forms than in non-GEM/rafts. This might be a mechanism for the decreased tumor properties in the transfectants of GM1/GD1b/GA1 synthase cDNA.
authors.affiliation: Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Dong
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Ikeda
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hamamura
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kondo
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Yuhsuke
authors.initials: Y
authors.lastname: Ohmi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Keiko
authors.initials: K
authors.lastname: Furukawa
authors.forename: Ryo
authors.initials: R
authors.lastname: Taguchi
authors.forename: Koichi
authors.initials: K
authors.lastname: Furukawa
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D002470:Cell Survival; D002855:Chromatography, Thin Layer; D050719:Crk-Associated Substrate Protein / Q000378:metabolism; D005434:Flow Cytometry; D051147:Ganglioside Galactosyltransferase / Q000235:genetics / Q000378:metabolism*; D005732:Gangliosides / Q000378:metabolism*; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D021962:Membrane Microdomains / Q000378:metabolism*; D051419:Paxillin / Q000378:metabolism; D010766:Phosphorylation; D014162:Transfection
chemical_list: C493841:BCAR1 protein, human; D050719:Crk-Associated Substrate Protein; D005732:Gangliosides; C496061:PXN protein, human; D051419:Paxillin; C033851:ganglioside, GD1b; C016481:trisialoganglioside GT1; C026226:ganglioside, GD3; D051147:Ganglioside Galactosyltransferase