The effect of cinobufacini injection on DNA topoisomerase Ⅰ of human hepatocellular carcinoma HepG-2 cells / 中国癌症杂志

ABSTRACT

Background and purpose:The cinobufacini injection is a traditional antitumor drug.However,its mechanism iS still unclear.The purpose of this study was to observe the effect of cinobufacini injections in DNA TOPO Ⅰ of human hepatocellular carcinoma HcpG-2 cells.Methods:The cells that were proliferated were assessed by MTT assay.Cell cycles were shown through FCM.TOPO Ⅰ mRNA expression was analyzed through RT-PCR.The activity of TOPO Ⅰ was measured by TOPO Ⅰ mediated super coiled PHR322 relaxation.Supercoiled PBR322 was also used to determine the direct DNA breakages.Results:Cinobufacini injections significantly inhibited HepG-2 cells proliferation in ways that were dependent on dosages and time.Induced tumor cells arrest at the S-phase.TOPO ⅠmRNA expression decreased in a manner that was dependent on dosages which inhibited the TOPO Ⅰ mediated DNA relaxations.However,the cinobufacini injections could not directly induce DNA breakage at any concentration.Conclusion:Cinobufacini injections can inhibit human hepatocellular carcinoma HepG-2 cells proliferation.The regulation of topoisomerase Ⅰ activity and mRNA expression may be one of the mechanisms that causes the cinobufacini injection to contribute against tumor.