Effects of PARP-1 inhibitors AG-014699 and AZD2281 on proliferation and apoptosis of human hepatoma cell line HepG2

Objective To observe the inhibitory and pro- apoptotic effects of two poly( ADP- ribose) polymerase( PARP- 1) inhibitors,AG- 014699 and AZD2281,on human hepatoma Hep G2 cells and preliminarily explore the mechanism by which AG- 014699 induces Hep G2 cell apoptosis,and to provide a new therapeutic target for hepatoma. Methods The effects of different concentrations of AG-014699 and AZD2281 on Hep G2 cell proliferation were determined by MTT assay. The cell apoptosis rate was measured by flow cytometry.The expression levels of caspase- 3 and caspase- 8 were measured by Western Blot. Inter- group comparison was made by t test. Results Both AG- 014699 and AZD2281 suppressed Hep G2 cell proliferation in a time- and dose- dependent manner. However,the sensitivity of Hep G2 cells to the two PARP- 1 inhibitors was different. The half- maximal inhibitory concentrations of AG- 014699 and AZD2281 at48 h determined by MTT assay were about 20 μmol / L and 400 μmol / L,respectively. Flow cytometry and Western blot were not used to evaluate the apoptosis of Hep G2 cells exposed to AZD2281 to which these cells were not sensitive. Hep G2 cell apoptosis could be induced by10,30,and 50 μmol / L AG- 014699,and the highest apoptosis rate at 48 h was significantly higher than that of the control group( 31. 00% ± 2. 13% vs 0. 9% ± 0. 013%,P < 0. 01). Compared with those in the control group,the protein levels of caspase- 3 and caspase- 8 in Hep G2 cells after 48- h exposure to 30,and 50 μmol / L AG- 014699 increased. Conclusion The two PARP- 1 inhibitors AG- 014699 and AZD2281 can inhibit the proliferation of Hep G2 cells,which showed different sensitivities to the two inhibitors. AG-014699 can induce Hep G2 cell apoptosis by up- regulating the protein expression of caspase- 3 and caspase- 8.