Mechanisms of arsenic trioxide induced apoptosis of human cervical cancer HeLa cells and protection by Bcl-2

It was recently reported that arsenic trioxide （AsO） can induce complete remission in patients with acute promyelocytic leukemia （APL）. In this present article, the biological effect of AsOon human cervical cancer HeLa cells and HeLa cells overexpressing Bcl-2 is studied. By MTT and colony forming ability assays, morphology alteration, flow cytometric analysis, DNA gel electrephoresis and in situ cell death detection （TUNEL）, it was found that AsOinhibited the growth of HeLa cells and induced G2/M arrest and apoptosis of the cells. RT-PCR, Northern blot, Western blot analysis revealed that AsOinduced HeLa cell apoptosis possibly via decreasing the expression of c-myc and viral genes. HeLa cells overexpressing Bcl-2 partly resist AsOinduced apoptosis, which might be relative to preventing the cells from AsOcaused G2/M block, downregulation of c-myc gene expression and inhibition of viral gene expression was also noted, However, it was found that AsOat a high concentratio