Figure 8.

Functional coupling of MC1R to the ERK pathway in human melanoma cell lines is dependent on cKIT expression. A, Expression of cKIT in human melanoma cell lines. Cell extracts from LOCE-MM28, 61, 79, 94, 98, 104, 117, 118, and 119 human melanoma cells were analyzed for cKIT expression by Western blot. B, Effects of NDP-MSH on pERK levels in cKIT positive and negative human melanoma cells. After serum deprivation, cultures of the indicated cell lines were stimulated with NDP-MSH, and ERK phosphorylation was compared by Western blot. C, Quantification of ERK activation in cKIT positive and negative human melanoma cells. Two independent blots as shown in B were quantified, and the intensity of the pERK signal was normalized to the intensity of the band in control cells, after correction for loading. Results are given as fold increase in pERK (mean ± range).