SKLB-M8 induces apoptosis through the AKT/mTOR signaling pathway in melanoma models and inhibits angiogenesis with decrease of ERK1/2 phosphorylation

Sklb-m8,a derivative of millepachine,showed significant anti-proliferative effects in melanoma cell lines. in this study,we investigated the anti-melanoma and anti-angiogenic activity of sklb-m8 on three melanoma cell lines (a2058,chl-1,and b16f10) and human umbilical vein endothelial cells (huvecs). in vitro,sklb-m8 showed anti-proliferative activity with ic50 values of 0.07,0.25,and 0.88 μm in a2058,chl-1,and b16f10 cell lines,respectively. flow cytometory analysis showed that sklb-m8 induced g2/m arrest in three melanoma cell lines,and western blotting demonstrated that sklb-m8 down-regulated the expression of cdc2,up-regulated p53 in a2058 and chl-1 cells,and triggered cell apoptosis through down-regulating akt and phosphorylated mtor (p-mtor). sklb-m8 also inhibited huvec proliferation,migration,invasion,and tube formation in vitro with the inhibition of phosphorylated erk1/2 (p-erk1/2). in vivo,alginate-encapsulated tumor cell assay revealed that sklb-m8 suppressed b16f10 tumor angiogenesis. in chl-1- and b16f10-tumor-bearing mouse models,sklb-m8 inhibited tumor growth by oral treatment with less toxicity. cd31 immunofluoresence staining and caspase-3 immunohistochemistry indicated that sklb-m8 inhibited melanoma tumor growth by targeting angiogenesis and inducing caspase3-dependent apoptosis. sklb-m8 might be a potential anti-melanoma drug candidate. © the japanese pharmacological society.