The Effects Of 17-β Estradiol On The Proliferation Of Human Mucoepidermoid Carcinoma Mc3 Cells

The effects of 17-B Estradiol (E2) on the proliferation of human mucoepidermoid carcinoma Mc3 cells were investigated proliferation with cell counting, MTT assay, colonogenic assay, flow cytometry, immunohistochemical staining and tumor growth in nude mice. The effects of E2 on the expression of CyclinDl, PCNA, Bcl-2 and P27 were studied by immunchistochemistry. Following results were obtained:1.E2 may promoted Mc3 cell proliferation(1). E2 promoted Mc3 cell proliferation in a dose-dependent and time- dependent manner at 10-9~10-7mol/L . In the groups of control, 10-9, 10-8 and 10-7mol/LE2 treated the cells the population doubling time(h)of the cells were 36.0, 27.9, 28.8 and 25.7 respectively. (2). After exposure to E2 at 10-9 10-8 or 10-7mol/L for 7 days, the proliferation of the Mc3 cells were increased (%) by 29,54 and 59 respectively.(3). The Colony-forming efficiency (%) of the control group and of the cells treated with E2 at 10-9, 10-8 and 10-7mol/L was 13. 7, 18. 1, 17. 6 and 20. 8 respectively. (4). When the cells had been treated with with E2 at 10-7mol/L for12h, 18h and 24h, the proliferation index (PI) were 49. 5, 27.5 and33. 6 respectively. The cell number in the S and G2/M phase increased,and that in G1/G0 phase decreased, When the cells were treated withE2 at 10~7mol/L for 24h, cells number of S phase increased from 11. 0to 33. 6,especialy.(5). Tumor growth in mude mice treated with E2 for 22days, Increased(%) by 563.7,926.2,949.5,553.9,455.1.2. E2 increased the expression of CyclinDl, PCNA, Bcl-2 anddecreased the expression of P27 in cuitured Mc3 cells and insections prepared from paraffin-embedded tumor specimens obtainedfrom Mc3 cell transplanted nude mice.(1). Mc3 cells showed positive stainingwith the antibodies ofCyclinDl, PCNA, Bcl-2. The protein expression of CyclinDl, PCNA,Bcl-2 in the groups of control, 10-9, 10-8 and 10-7mol/L. CyclinDlexpression increased(%) by 16,19 and 24; PCNA expression (% ofpositive) was 62, 78, 74 and 98; Bcl-2 expression (% of positive)was 48, 82, 77 and 93, respectively.(2). P27 expression in the cells treated with E2 at 10-9 10-8 and10-7mol/L was decreased(%) by 33,30 and 55 respectively.Conclusion: E2 may promote the transfer of Mc3 cells from G1 to S phase at a certain range of concentration, Increase of the cell number in the S phase and the proliferation index (PI), and promote of the DNA synthesis. Increase of CyclinDl, PCNA and Bcl-2 and decrease of P27 may be related to the promotion of proliferation of E2 on Mc3 cells.