RESUMO
Sex hormones from environmental and physiological sources might play a major role in the pathogenesis of hepatoblastoma in children. This study investigated the effects of estradiol and bisphenol A on the proliferation and telomerase activity of human hepatoblastoma HepG2 cells. The cells were divided into 6 treatment groups: control, bisphenol A, estradiol, anti-estrogen ICI 182,780 (hereinafter ICI), bisphenol A+ICI, and estradiol+ICI. Cell proliferation was measured based on average absorbance using the Cell Counting-8 assay. The cell cycle distribution and apoptotic index were determined by flow cytometry. Telomerase activity was detected by polymerase chain reaction and a telomeric repeat amplification protocol assay. A higher cell density was observed in bisphenol A (P<0.01) and estradiol (P<0.05) groups compared with the control group. Cell numbers in S and G2/M phases after treatment for 48 h were higher (P<0.05), while the apoptotic index was lower (P<0.05) and telomerase activities at 48 and 72 h (P<0.05) were higher in these groups than in the control group. The cell density was also higher in bisphenol A+ICI (P<0.01) and estradiol+ICI (P<0.05) groups compared with the ICI group. Furthermore, cell numbers were increased in S and G2/M phases (P<0.05), while the apoptotic index was lower (P<0.05) and telomerase activities at 48 and 72 h were higher (P<0.05) in these groups than in the ICI group. Therefore, bisphenol A and estradiol promote HepG2 cell proliferation in vitro by inhibition of apoptosis and stimulation of telomerase activity via an estrogen receptor-dependent pathway.