Mda-7-carrying replication-defective adenovirus selectively kills hepatocellular carcinoma cells by facilitating release of proapoptotic protein from mitochondria / 中华肿瘤杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the mechanism that mda-7/IL-24 selectively kills hepatocellular carcinoma (HCC) HepG2 cells in vitro.</p><p><b>METHODS</b>HCC cell line HepG2 and normal liver cell line L02 were infected with Ad.mda-7. The expression of mda-7/IL-24 was detected by RT-PCR and ELISA, respectively. The apoptotic effects were confirmed by Hoechst staining and flow cytometry assay, respectively. Furthermore, Bcl-2 family proteins, cytochrome C, Smac/DIABLO and caspase-9 were determined by Western blot.</p><p><b>RESULTS</b>The exogenous mda-7/IL-24 gene was expressed in HepG2 and L02 cells infected with Ad.mda-7. Ad.mda-7 induced apoptosis in HepG2 but not in L02 cells in vitro. The induction of tumor cell apoptosis is correlated with the increasing expression of Bax and decreasing expression of Bcl-2 and Bcl-xL genes, then facilitated the releasing of cytochrome C and Smac/DIABLO from mitochondria to cytoplasm and increasing the expression of caspase-9, eventually, resulted in apoptosis.</p><p><b>CONCLUSION</b>Ad.mda-7 selectively induces growth inhibition and apoptosis in hepatocellular carcinoma HepG2 cells but not in normal L02 hepatocytes in vitro, and the mechanism might involve the decrease of Bcl-2 and Bcl-xL and increase of Bak expression, facilitating the release of cytochrome C and Smac/DIABLO from mitochondria in HCC cells.</p>