| Backgrounds and Purpose:Recently great attention has been paid to the effect of estrogens and environmental estrogens on human health with the rapid development of the economy and the society and aggravation of the pollution.There has been increasing interest in the effect of estrogens and environmental estrogens to estrogen-sensitive malignancies,but research on the relationship of estrogens and environmental estrogens to children tumors is rare.Hepatoblastoma is the most common malignant liver tumor in children.The etiology is not clear.Great attention has been paid to exposure of parents to environmental factors in the pre-pregnancy and pregnancy.In order to study the proliferation effect and the mechanism of estrogens and environmental estrogens on human heptoblastoma cell line HepG2,we devised 17-beta-estradiol and bisphenol A as intervention substances and investigated the cell cycle,cell apoptosis and telomerase activity.Materials and Methods:1.Experiment grouping:HepG2 cells were cultured in estrogen-free medium and divided into six groups:group 1,no treatment(Control);group 2,treated with bisphenol A(BPA); group 3,treated with 17-beta-estradiol(E2);group 4,treated with ICI 182,780(ICI); group 5,treated with both BPA and ICI;group 4,treated with both E2 and ICI.2.Test of absorbance value of HepG2:Absorbance value(AV) was tested at time 0,24,48,72,96 and 120 hours respectively,and growth curve was drawn.3.Test of cell cycle and apoptosis index of HepG2:the cell culture and the group was the same as above.Cell cycle and apoptosis index was tested at time 48 hours by flow cytometer.4.Test of telomerase activity of HepG2:cells were cultured and telomerase activity of every group was tested at time 24,48 and 72 h by real-time fluorescent quantitative polymerase chain reaction.Results:1.Test of AV of HepG2:AV of group 1,2,3,4,5 and 6 were 0.46±0.03,0.66±0.02(p＜0.01 vs group1),0.70±0.01(p＜0.01 vs group1),0.43±0.00,0.79±0.01(p＜0.01 vs group4) and 0.81±0.04(p＜0.01 vs group 4) respectively at 48 hours.AV of group 1,2,3,4,5 and 6 at 96 hours were 0.70±0.15,1.52±0.15(p＜0.05 vs group 1),1.31±0.25,0.76±0.12,2.03±0.30(P＜0.01 vs group 4) and 1.72±0.26(p＜0.01 vs group 4) respectively.There is no statistical difference at time 24,96 and 120 hours compared group 1 with group 4,group 2 with group 5 or group 3 with group 6 (p＞0.05).2.Test of cell cycle and apoptosis index of HepG2:There was no statistical difference in cell cycle distribution at time 48 hours in all groups(p＞0.05).At 48 hours AI of group 1,2,3,4,5and 6 were 12.99±0.58%,5.72±1.86%(p＜0.01 vs group1),6.81±1.63%(p＜0.01 vs group1),2.39±1.05%,6.67±0.76%(p＜0.01 vs group 4) and 6.39±1.56%(p＜0.01 vs group 4) respectively.There was no statistical difference at time 48 hours compared group 1 with group 4,group 2 with group 5 or group 3 with group 6(p＞0.05).3.Test of telomerase activity of HepG2:At 48 hours telomerase activity of group 2,3 was 3.2 times(p＜0.01 vs goup1 ) and 3.5 times(p＜0.01 vs goup1 ) as group 1 respectively and group 5 and 6 was 2.3 times(p＜0.01 vs goup 4) and 3.3 times(p＜0.01 vs goup 4) as group4 respectively.,At 72 hours telomerase activity of group 2,3 was 3.2 times(p＜0.01 vs goup1) and 3.0 times(p＜0.01 vs goup1 ) as group 1 respectively and group 5 and 6 was 2.8 times(p＜0.01 vs goup 4 ) and 2.9 times(p＜0.01 vs goup 4 ) as group 4 respectively., There is no statistical difference in telomerase activity at time 24,48 and 72 hours compared group 1 with group 4,group 2 with group 5 or group 3 with group 6(p＞0.05).According to the curve we can find that there is no significant difference in both group 1 and group 4 at 24,48 and 72 hours.But there is great increase from 24 hours to 48 hours in other groups.The increasing speed from 48 hours to 72 hours decelerates.Conclusions1.E2 and BPA can promote human hepatoblastoma HepG2 cell proliferation in vitro.2.The cell proliferation effect of E2 and BPA on HepG2 is associated with the suppression of cell apoptosis.3.E2 and BPA can enhance the telomerase activity of HepG2,and this may be the cause of the suppression of HepG2 cell apoptosis.4.The cell proliferation effect of E2 and BPA on HepG2 can not be eliminated by ICI,and it is associatied with the estrogen receptor independent pathway.
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