[Mda-7-carrying replication-defective adenovirus selectively kills hepatocellular carcinoma cells by facilitating release of proapoptotic protein from mitochondria].
OBJECTIVE
To investigate the mechanism that mda-7/IL-24 selectively kills hepatocellular carcinoma (HCC) HepG2 cells in vitro.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Wang
Cong-Jun
CJ
Department of General Surgery, The First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai 200080, China.
Peng
Zhi-Hai
ZH
Zheng
Jian-Wei
JW
Chen
Kun
K
Hu
Hui-Yi
HY
Ji
Wen-Wei
WW
Yu
Yuan
Y
Xue
Xin-Bo
XB
D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D053453:Caspase 9 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism*; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000166:cytology; D006801:Humans; D007378:Interleukins / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014162:Transfection; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism; D000099180:Interleukin-24
D051017:Apoptosis Regulatory Proteins; D053453:Caspase 9; D045304:Cytochromes c; D007378:Interleukins; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D000099180:Interleukin-24; C412403:DIABLO protein, human