ABSTRACT
Bile acids and their synthetic derivatives induced apoptosis in various kinds of cancer cells and anticancer effects. It has been reported that the synthetic chenodeoxycholic acid (CDCA) derivatives showed apoptosis-inducing activity on various cancer cells in vitro. It wasn't discovered those materials have apoptosis-inducing effects on G361 human melanoma cells. The present study was done to examine the synthetic bile acid derivatives, HS-1199 and HS-1200, induced apoptosis on G361 cells and such these apoptosis events. The viability of G361 cells was assessed by the MTT assay. Induction of apoptosis was confirmed by DNA electrophoresis and Hoechst staining. Westen blot analysis and immunofluorescent staining were performed to study the alterations in expression level and translocation of apoptosis-related proteins. Proteasome activity and mitochondrial membrane potential (MMP) change were also assayed. Tested G361 cells showed several lines of apoptotic manifestation such as activation of caspase-3, DFF and PARP, DNA degradation (HS-1200 only), nuclear condensation, inhibition of proteasome activity, reduction of mitochondrial membrane potential, and the release of cytochrome c and AIF to cytosol. Between two synthetic derivatives, HS-1200 showed stronger apoptosis-inducing effect than HS-1199 did. Taken collectively, we here demonstrated for the first time that synthetic CDCA dedrivatives induce apoptosis of human melanoma cells through the proteasome, mitochondria and caspase pathway. Therefore our data provide the possibility that HS-1200 could be considered as a novel therapeutic strategy for human melanoma cells from its powerful apoptosis-inducing activity.