Apoptotic Effect of Co-treatment with Chios Gum Mastic and HS-1200 on G361 Human Melanoma Cell Line / 대한해부학회지

Chios gum mastic (CGM) is a resinous exudate obtained from the stem and the main leaves of Pistacia lenticulus tree native to Mediterranean areas. Recently it reported that CGM induce apoptosis in a few cancer cells in vitro. 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. This study was undertaken to investigate the synergistic apoptotic effect of cotreatment with a natural product, CGM and a CDCA derivative, HS-1200 on G361 human melanoma cells. To investigate whether the co-treatment of CGM and HS-1200 compared with each single treatment efficiently reduced the viability of G361 cells, MTT assay was conducted. To investigate augmentation of apoptosis in G631 cells co-treated with CGM and HS-1200, DNA electrophoresis, Hoechst staining, proteasome activity assay, flow cytometry, Westen blot analyses, immunofluorescent staining and confocal microscopy were performed. In this study, G361 cells co-treated with CGM and HS-1200 showed several lines of apoptotic manifestation such as nuclear condensations, DNA fragmentation, the reduction of MMP and proteasome activity, the decrease of DNA content, the release of cytochrome c into cytosol, the translocation of AIF and DFF40 (CAD) onto nuclei, activation of caspase-9, caspase-3, PARP and DFF45 (ICAD), and up-regulation of Bax whereas each single treated G361 cells did not. Although the single treatment of 40 micro/mL CGM or 25 micro HS-1200 for 24 hrs did not induce apoptosis, the co-treatment of them induced prominently apoptosis. Therefore, combination therapy of CGM and HS-1200 could be considered, in the future, as an alternative therapeutic strategy for human melanoma.

Induction of Apoptosis by Genistein in Human Melanoma Cells / 대한해부학회지

Genistein is a naturally occurring isoflavone that has been identified predominantly in soybean. It has been found that genistein can inhibit the growth of various cancer cell lines. Melanoma continues to increase in incidence in many parts of the world and remains among the top six cancers as a cause of death and morbidity. Understanding and overcoming resistance mechanism(s) of melanoma to apoptosis would therefore facilitate identification of new therapeutic targets and development of new treatments. This study was undertaken to investigate whether genistein induced apoptosis on human melanoma cells (G361). Genistein had a significant dose- and time-dependent inhibitory effect on the viability of G361 cells. The death of cells was further demonstrated to be due to apoptosis characterized by chromatin condensation and apoptotic bodies by hoechst staining, and DNA electrophoresis. p53 levels were not altered by genistein treatment. Genistein treatment induced caspase-3 cleavage and activation. Poly (ADP-ribose)-polymerase (PARP) and DNA fragmentation factor 45 (DFF45), which are caspase-3 substrates, were cleaved during genistein-induced apoptosis. It was found that the caspase-6 substrate lamin A was cleaved, whose cleavage has been reported to be necessary for complete condensation of DNA during apoptosis. The expression level and phosphorylation of focal adhesion kinase (FAK) were reduced by genistein treatment. These results suggest that genistein may constitute a potential antitumor compound against melanoma occurring at oral mucosa and skin.