Trichostatin A Increases Sensitivity of Hepatocellular Carcinoma Cells Bel7402 to TRAIL

Objective To investigate the effect of Trichostatin A(TSA) combined with tumor necrosis factor(TNF) related apoptosis inducing ligand(TRAIL) on the proliferation and apoptosis of human hepatocellular carcinoma cell line Bel7402 in vitro, and to explore the possible mechanism. Methods The inhibitory effect of TSA, TRAIL, low concentration TSA combined with TRAIL on the proliferation of Bel7402 cells were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) staining method; 4,6-diamidino-2-phenylindole dihydrochlorid(DAPI) staining method was applied to display the apoptosome morphology of hepatocellular carcinoma cells; the expression and subcellular location of p65 were investigated by immunocytochemistry and Western blot. Results There was no influence of different concentrations of TSA on the proliferation of Bel7402 cells for 6, 12 and 24 h, but the proliferation of Bel7402 cells were inhibited significantly after 48 h, compared with control group(P<0.05). The proliferation of Bel7402 cells also had little change while treated with TRAIL; Pretreatment of TSA(20 ng/ml) could increase the sensitivity of Bel7402 cells to TRAIL. The survival rate of Bel7402 cells were (57.1±5.4)% after pretreated with TSA(20ng/ml) combined with TRAIL (100ng/ml) for 24h, compared with control group(P<0.05). DAPI staining method indicated that Bel7402 cells were trended to characteristic morphological changes of apoptosis when treated with TSA combined with TRAIL. Fluorescence microscope confirmed that the expression and location of p65 presented dominantly in ytoplasm, however, the translocation of p65 from the cytoplasm into the nucleus were repressed when treated with TSA (200ng/ml) or TRAIL(100ng/ml) for 24h. While the translocation and accumulation of p65 from cytoplasm to nucleus were increased and the expression of p65 were repressed when treated with low concentration of TSA combined with TRAIL. Conclusion TSA has a capacity to enhance TRAIL-induced apoptosis of hepatocellular carcinoma cells Bel7402; TSA combined with TRAIL inducing the apoptosis of Bel7402 cells may be involved in decreasing the expression and activity of p65．