Growth arrest and apoptosis of the human hepatocellular carcinoma cell line BEL-7402 induced by melittin

OBJECTIVE: The aim of this study was to investigate the cellular effects of melittin on the growth and apoptosis of human hepatocellular carcinoma (HCC) cells and to provide the molecular mechanism for potential application of a recombinant adenovirus carrying the melittin gene (Ad-rAFP-Mel) in the treatment of liver cancer. METHODS: Human HCC cells (BEL-7402) were infected with Ad-rAFPMel at different times. In vitro cell growth was determined by MTT assay. Cellular apoptosis was evaluated quantitatively and qualitatively by phase-contrast microscopy, transmission electron microscopy, DNA ladder electrophoresis, TUNEL staining and flow cytometry. RESULTS: Ad-rAFP-Mel infection had an inhibitory effect on the proliferation of BEL-7402 cells. The morphological changes of apoptosis were confirmed by microscopy and DNA electrophoresis. The ultrastructural characteristics of apoptotic cells, such as chromatin condensation and nuclear fragmentation, were also observed by electron microscopy in the Ad-rAFP-Mel-infected cells. Ad-rAFPMel infection markedly induced cellular apoptosis, and Fas expression on Bel-7402 cells infected by Ad-rAFPMel was up-regulated. CONCLUSION: The fact that melittin can induce apoptosis of the HCC cell line BEL-7402 leads us to consider adenovirus-mediated delivery of melittin as a promising approach for the treatment of HCC. However, the underlying mechanism needs to be further investigated.