Effects of pristimerin on proliferation, migration and cell cycle of colorectal cancer HCT116 and HT29 cells and its action mechanism

Objective To investigate impacts of pristimerin on proliferation, migration and cell cycle of colorectal cancer HCT116 and HT29 cells and uncover the potential mechanism.

Methods Cell viability of HCT116 and HT29 cells treated with pristimerin at various concentrations was measured by Methyl Thiazolyl Tetrazolium (MTT) assay at different time points. The proliferation of HCT116 cells and HT29 cells treated with pristimerin at various concentrations was detected by 5-acetyney-2'-deoxyuridine (EdU) assay. Transwell experiment was performed to observe the effects of different concentrations of pristimerin on migration of HCT116 cells and HT29 cells. The influence of pristimerin on cell cycle of HCT116 cells and HT29 cells was tested by flow cytometry. Western blot was used to determine its impact on cell cycle-related proteins including cyclin E1, CDK2, p53, p27 and p21 as well as PI3K/Akt/mTOR signaling pathways.

Results MTT tests revealed that the viability of HCT116 and HT29 cells after 12, 24, 36, 48 and 60 h treated by different concentrations of pristimerin decreased significantly, and changed in a dose and time-dependent manner. EdU tests showed that the positive cell rates of HCT116 cells treated with 0.5, 1, 2 μmol/L pristimerin for 24 h were lower than those of the control group, the difference was statistically significant (P < 0.001). After treatment with 1, 2 and 4 μmol/L pristimerin for 24 h, the positive cell rates of HT29 cells were lower than those of the control group, the difference was statistically significant (P < 0.001). Transwell experiment results showed that the number of HCT116 cells penetrating the subventricular membrane decreased, and the cell migration rates were lower than that of control cells after treatment with 0.5, 1, 2 μmol/L pristimerin for 24 h (P < 0.001). Flow cytometry results showed that pristimerin could induce cell cycle arrest of HCT116 and HT29 cells at G₀/G₁ stages. Western blot results displayed that p53, p21 and p27 protein expression were up-regulated and the expression of cyclin E1, CDK2, p-PI3K, p-Akt, mTOR and p-mTOR was down-regulated in HCT116 and HT29 cells treated by pristimerin(P < 0.05, P < 0.01 or P < 0.001).

Conclusion Pristimerin could exert the proliferation and migration of HCT116 and HT29 cells, induce arrest at G₀/G₁ stages, and the molecular mechanism may be related to PI3K/Akt/mTOR signaling pathway.