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>
Subject(s)
Humans , Adenoviridae , Genetics , Apoptosis , Caspase 9 , Metabolism , Cytochromes c , Metabolism , Hep G2 Cells , Hepatocytes , Cell Biology , Interleukins , Genetics , Metabolism , Intracellular Signaling Peptides and Proteins , Metabolism , Mitochondria , Metabolism , Mitochondrial Proteins , Metabolism , Proto-Oncogene Proteins c-bcl-2 , Metabolism , Transfection , bcl-2-Associated X Protein , Metabolism , bcl-X Protein , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) on the hepatocellular carcinoma cell lines and normal liver cell line in vitro.</p><p><b>METHODS</b>Hepatocellular carcinoma cell lines HepG2, SMMC7721, Hep3B, MHCC97L, M6 and normal liver cell line L02 were infected with Ad.mda-7. The gene expression of mda-7/IL-24 in these cell lines was confirmed by RT-PCR and ELISA assay. MTT assay and flow cytometry were used to study tumor cell proliferation and cell cycle in vitro. Hoechst staining and cytometry assay after Annexin-V and PI staining were studied to indicate the apoptosis effect.</p><p><b>RESULTS</b>It was confirmed by RT-PCR that the exogenous mda-7/IL-24 gene expressed in all of these cells. The mda-7/IL-24 protein product was confirmed by assaying the supernatant with ELISA. MTT and apoptosis test indicated mda-7/IL-24 can induce the hepatocellular carcinoma cell lines growth suppression, apoptosis in vitro but not in normal liver cell line L02, cell cycle test revealed mda-7/IL-24 can block cancer cell lines in G2/M but not in L02.</p><p><b>CONCLUSIONS</b>mda-7/IL-24 selectively induces growth suppression, apoptosis in hepatocellular carcinoma lines but not in normal liver cell in vitro.</p>