Abstract: Objective To investigate the effects of different concentrations of β-estradiol(E₂)on the proliferation of Hela cells in cervical cancer and the mechanism. Methods Hela cells cultured in vitro were divided into control, low concentration and high concentration groups. The effects of E₂ on the proliferation were detected with CCK8 assay and cell clone formation assay. The effects of E₂ on the apoptosis, cell cycle and migration were detected with flow cytometry and Transwell assay, respectively. In the control and high concentration groups, the mRNA expressions of HPV18 E6, E7, p21, p53, CDK2 and Rb were detected with qRT-PCR; the protein expressions of p21, p53, CDK2, Rb and Rb phosphorylation(pRb)were detected with Western blotting. Results Compared with the control and low concentration groups, the high concentration group had reduced cell growth rate(P<0.001), inhibited cell cloning(P=0.013)and prolonged G0/G1 phase(P<0.001). High concentration of E₂ reduced the mRNA expressions of HPV18 E6/E7(P=0.049, P=0.043), downregulated the mRNA and protein expressions of CDK2 and Rb(P_{CDK2 mRNA}=0.035, P_{Rb mRNA}=0.003, P_{CDK2 protein}=0.009, P_{Rb protein}=0.008), upregulated the mRNA and protein expressions of p21 and p53(P_{p21 mRNA}=0.042, P_{p53 mRNA}=0.035, P_{p21 protein}=0.039, P_{p53 protein}=0.043), and downregulated pRb(P<0.001). Conclusion High concentration of E₂ inhibits the proliferation of Hela cells. The mechanism might be related to the inhibition of HPV18 E6/E7 oncogene, promotion of the protein expressions of p53 and p21, and regulation of cell cycle protein(CDK2, Rb)levels, thus affecting the normal cell cycle.

Key words: Estrogen, Cell cycle, Cervical cancer cells, Cytological behavior, Human papillomavirus