Ganglioside GD3 induces convergence and synergism of adhesion and hepatocyte growth factor/Met signals in melanomas.
Bottom Line: In this study, we analyzed the effects of GD3 expression on cell signals triggered by hepatocyte growth factor (HGF)/Met interaction and by adhesion to collagen type I (CL-I).When resistance to induced apoptosis by H2O2 was examined, only GD3+ cells treated with both HGF and adhesion to CL-I showed clearly low percentages of dead cells compared with GD3- cells or GD3+ cells treated with either one of the stimulants.Cell growth measured by 5-ethynyl-2' deoxyuridine uptake also showed synergistic effects in GD3+ cells.
Affiliation: Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan; Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya, Japan.Show MeSH
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Mentions: We then analyzed phosphorylation of Erks by either HGF stimulation or adhesion to CL-I, or both of them at the same time, in GD3+ and GD3− cells. After starving for 14–16 h in serum-free DMEM, the cells were harvested and rotated for 1 h at 37°C to reduce basal phosphorylation levels of Erks. Phosphorylation levels of Erks by HGF stimulation were slightly higher in GD3+ cells than in GD3− cells (Fig.4A). As for adhesion stimulation to CL-I, phosphorylation levels of Erks were not different between GD3+ cells and GD3− cells (Fig.4B). We then costimulated GD3+ and GD3− cells with HGF and adhesion, and analyzed phosphorylation levels of Erks. In this case, phosphorylation levels of Erks were remarkably increased in GD3+ cells compared with GD3− cells (Fig.4C). Among four bands in total Erks detected after the stimulation, new bands above original Erk1/2, representing phosphorylated forms of Erk1/2, were more prominent in GD3+ cells than in GD3− cells after costimulation. These results suggested that phosphorylation of Erks was synergistically enhanced by costimulation with HGF and adhesion to CL-I in GD3+ cells.
Affiliation: Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan; Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya, Japan.