The effect of arsenic trioxide on human hepatoma cell line BEL-7402 culturedin vitro

AIM To study the effect of a wide range of concentration of arsenic trioxide on human hepatoma cell lineBEL-7402 and its mechanism.METHODS The BEL-7402 cells were treated with arsenic trioxide (a final concentration of 0.5, 1 and2 μmol/L, respectively) in various durations or for 4 successive days. The cell growth and proliferation wereobserved by cell counting and cell-growth curve. Morphologic changes were studied under electronmicroscopy. Flow cytometry was used to assay cell-DNA distribution and the protein expression of Bcl-2 andBax was detected by immunocytochemical method.RESULTS The cell growth was significantly inhibited by the different concentrations of arsenic trioxide asrevealed by cell counting and cell-growth curve. Arsenic trioxide treatment at 0.5, 1 and 2 μmol/L, resultedin a sub-G1 cell peak. The decreased G0/G1 phase cell and the increased percentage of S phase cell were observed by flow cytometer, suggesting that the inhibiting effect of arsernic trioxide on BEL-7402 cell lay inG0/G1 phase cell. Apoptotis-related morphology, such as intact cell membrane, nucleic condensation,apoptotic body formation, can be seen under the electron microscopy. High protein expression level of Bcl-2and Bax was detected in 1 and 2 μmol/L arsenic trioxide-treated cells, but that of Bax was more significant.Arsenic trioxide treatment at 0.5 μmol/L resulted in higher expression level of Bcl-2 and lower expressionlevel of Bax compared with control (P1<0.01, P2<0.01).CONCLUSION Arsenic trioxide not only inhibited the proliferation but also induced apoptosis of humanhepatoma cell line BEL-7402. The induced-apoptosis effect of 1 and 2 μmol/L arsenic trioxide was relative tothe expression level of Bcl-2 and Bax.