title: Lyso-GM3, its dimer, and multimer: their synthesis, and their effect on epidermal growth factor-induced receptor tyrosine kinase.
abstract: Glycosphingolipids, particularly gangliosides, are known to modulate growth factor receptor tyrosine kinase. A well-documented example is the inhibitory effect of GM3 on kinase associated with epidermal growth factor receptor (EGFR) in human epidermoid carcinoma A431 cells. Lyso-GM3 was detected as a minor component in A431 cells, and may function as an auxiliary factor in GM3-dependent inhibition of EGFR. We studied the inhibitory effect of chemically synthesized GM3, lyso-GM3, and its derivatives, on EGFR function, based on their interaction in membrane microdomain, with the following major findings: (1) GM3, EGFR, and caveolin coexist, but tetraspanins CD9 and CD82 are essentially absent, within the same low-density membrane fraction, separated by sucrose density gradient ultracentrifugation. (2) Strong interaction between EGFR and GM3 was indicated by increasing binding of EGFR to GM3-coated polystyrene beads, in a GM3 dose-dependent manner. Confocal microscopy results suggested that three components in the microdomain (GM3, EGFR, and caveolin) are closely associated. (3) Lyso-GM3 or lyso-GM3 dimer strongly inhibited EGFR kinase activity, in a dose-dependent manner, while lyso-GM3 trimer and tetramer did not. >50 microM lyso-GM3 was cytolytic, while >50 microM lyso-GM3 dimer was not cytolytic, yet inhibited EGFR kinase strongly. Thus, lyso-GM3 and its dimer exert an auxiliary effect on GM3-induced inhibition of EGFR kinase and cell growth, and lyso-GM3 dimer may be a good candidate for pharmacological inhibitor of epidermal tumor growth.
authors.affiliation: Pacific Northwest Research Institute, University of Washington, Seattle, WA 98122, USA.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Murozuka
authors.forename: Naoko
authors.initials: N
authors.lastname: Watanabe
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hatanaka
authors.forename: Sen-itiroh
authors.initials: SI
authors.lastname: Hakomori
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005679:G(M3) Ganglioside / Q000031:analogs & derivatives* / Q000737:chemistry; D018698:Glutamic Acid / Q000737:chemistry; D006801:Humans; D051861:Kangai-1 Protein / Q000096:biosynthesis; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D021962:Membrane Microdomains / Q000737:chemistry; D018613:Microscopy, Confocal; D008956:Models, Chemical; D017434:Protein Structure, Tertiary; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry*; D060245:Tetraspanin 29
chemical_list: D015703:Antigens, CD; C554869:CD9 protein, human; D005679:G(M3) Ganglioside; D051861:Kangai-1 Protein; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29; C056605:lyso-G(M3) ganglioside; D018698:Glutamic Acid; D004815:Epidermal Growth Factor; D020794:Receptor Protein-Tyrosine Kinases