Effects of GHSC-73 on proliferation and cell cycle of human hepatocellular carcinoma HepG2 cells / 第二军医大学学报

ABSTRACT

Objective: To investigate the effects of β-D-glucosyl-(1-4)-α-L- thevetosides of 17β-digitoxigenin (GHSC-73), an isolate from the seeds of Cerbera manghas L., on cell growth and cell cycle regulation of human hepatocellular carcinoma cell line HepG2, and to discuss the related mechanism. Methods: HepG2 cells were treated with different concentrations (0-80 μmol/L) of GHSC-73. Cell viability was determined using MTT assay at 24, 48, and 72 h after treatment. Cell cycle distribution was assessed by flow cytometry after propidium iodide (PI) staining. Expression of the S phase associated genes GADD153, cyclin D1, cyclin A2, DHFR, TYMS, and p21 was determined by real-time RT-PCR before and after GHSC-73 treatment. Results: GHSC-73 inhibited the cell proliferation of HepG2 cells in a dose- and time-dependent manner. The values of IC50 were (5.18±0.21), (0.37±0.08), and (1.66±0.16) μmol/L at 24, 48, and 72 h, respectively. Compared with control group, the proportion of cells in S phase increased in the treatment group with the prolongation of treatment, the cells in G0/G 1 phase gradually decreased (P<0.05), and cells in G2/M phase remained unchanged, indicating that GHSC-73 blocked HepG2 cell in S phase. Real-time RT-PCR showed that cyclin A2, DHFR, and TYMS were down-regulated, and p21, GADD153, and cyclin D1 were up-regulated, which might be associated with the GHSC-73-induced S phase arrest in HepG2 cells. Conclusion: GHSC-73 can inhibit growth of HepG2 cells by inducing S phase arrest) down-regulation of cyclin A2, DHFR, and TYMS genes and upregulation of p21, GADD153, and cyclin D1 genes might participate in the induction of arrest.