Effects of cinobufacini injection on cell proliferation and the expression of topoisomerases in human HepG‑2 hepatocellular carcinoma cells

Abstract The present study aimed to investigate the effects of cinobufacini injection on the proliferation and expression of topoisomerases in human HepG-2 hepatocarcinoma cells. The cells were divided into a control group and an experimental group, in which 0.105, 0.21, 0.42 mg/l cinobufacini was injected. Cell proliferation was assessed using a 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide assay, levels of apoptosis were detected using annexin V/propidium iodide staining and cell cycles were analyzed using flow cytometric analysis. The mRNA and protein expression levels of topoisomerase (TOPO) I and TOPO II were determined by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. Cinobufacini injection significantly inhibited the proliferation of the HepG-2 cells (P<0.05), induced apoptosis (P<0.05) in a dose- and time-dependent manner, induced tumor cell arrest at the S phase in a dose-dependent manner, and downregulated the mRNA and protein expression levels of TOPO I and TOPO II (P<0.05) in a dose-dependent manner. Therefore, cinobufacini was found to inhibit human HepG-2 hepatocellular carcinoma cell proliferation, and downregulation of the expression levels of TOPO I and TOPO II may contribute to the effect on proliferation observed in the Hep‑G2 cells following cinobbufacini injection.