The impact of c-Met inhibition on molecular features and metastatic potential of melanoma cells.

The aberrant activation of the hepatocyte growth factor receptor (c-Met) in malignant melanoma is associated with poor prognosis, fostering tumor progression, angiogenesis, and invasiveness. While therapeutic targeting of this pathway has shown promise in several tumors, our previous findings revealed increased tumorigenicity following tyrosine kinase inhibitor SU11274 treatment. Therefore, we hypothesized that administering c-Met inhibitors may elicit distinct effects in human melanoma cells. In this study, we investigated the influence of three c-Met inhibitors, SU11274, crizotinib, and PHA665752, on molecular characteristics, tumorigenicity, and metastatic behavior in three human melanoma cell lines, M4Beu, EGFP-A375 and its metastatic variant, EGFP-A375/Rel3 (Rel3). Crizotinib and PHA665752 induced upregulation of MET proto-oncogene, receptor tyrosine kinase (MET), alongside cancer stem cell marker Prominin 1 (CD133), pluripotency marker Nanog homeobox (Nanog), and genes encoding angiogenic factors and receptors in Rel3 cells, correlating with supportive effect on tumorigenicity in vivo. The increased tumorigenicity of the Rel3 cells following the SU11274 treatment correlated with the elevated phosphorylation of Akt, p70 S6 and RSK kinases. Our results demonstrate pleiotropic changes induced by small-molecule inhibitors of receptor tyrosine kinases in melanoma cell lines.