The Effect Of 17-beta Estradiol On The Metastastic Potential Of Human Salivary Gland Mucoepidermoid Carcinoma Mc3 Cells

Estrogen is effective in the treatment of many diseases and wildely used in clinical. In recent years, studies have shown that it may has the potential to induce or promote some estrogen-dependent tumors as well as many estrogen-independent cancers such as lung cancer, liver cancer, throat cancer and so on. However, the role it plays in tumor cell metastatic process is remained undefined. In this study, the effect of 17beta-estradiol(E2) on the metastatic potential of human salivary gland mucoepidermoid carcinoma Mc3 cells was investigated and the role of E2 in the tumor metastasis was studied.The effects of E2 on adhesion, invasion and motility potential of salivary mucoepidermoid carcinoma Mc3 cells were investigated with cell attachment assay on fibronectin (FN), wound assay, chemotaxis assay, gelatin -incorporated SDS-PAGE electrophoresis and tumor metastasis experiment in nude mice. Moreover, the effects of E2 on the expression of VEGF in highly metastatic salivary gland mucoepidermoid carcinoma Mc3 cells were investigated with the methods of immunohistochemistry. In Mc3 cells and the samples ofthe metastastic foci sectioned from the surfaces of nude mouse lungs, estrogen receptor (ERa) was determined by immunohistochemistry assay.Following results were obtained:1. Attachment rates of Mc3 cells treated withE2 at 10-9, 10-8, 10-7, 10-6M were 38.3%, 50.4%, 69.2% and 91.1% respectively, whereas that of the control was 25.0%. When exposed to E2 at 10-9,10-8,10-7 and 10-6 M for 48h, motility of Mc3 cells on FN was increased by 16.9%, 40.9%, 36.4% and 38.8% respectively. When at 10-6M, E2 increased chemotaxis potential of Mc3 cells to FN by 60.3%.2. The activity of 68kDa matrix metalloproteinase (MMP2) of Mc3 cells was enhanced at different levels by 10-9, 10-8 and 10-7M of E2, the most enhancement was observed at 10-6M.3. The number of metastatic foci on the lung surfaces in the nude mice treated with E2 at 5.2ug/day and that in the controls were 119.2 + 69.6 and 14.2+11.8 respectively.4. In vitro, the VEGF expression was significantly higher in Mc3 cells which had been treated with E2 at 10-7M for 24h than in the controls. Consisting with the assay in vitro, the higher VEGF expression was also detected in the samples of foci in the E2-treated nude mice.5. By immunohistochemistry, we detected nuclear ERa expression in vitro as well as in vivo.Conclusion: physiological and pharmacological concentration of E2 can promote the adhension of Mc3 cells to fibronectin(FN) membrane, increase mortility on FN and chemotaxis to FN, enhance the activity of matrix metalloproteinase and the expression of vascular endothelial growth factor(VEGF); increase the metastatic foci of Mc3 cells in lungs of nude mice treated with of E2 at clinical dose. At the same time, we detectedEra in Mc3 cells as well as in the metastatic foci. So, we concluded that physiological and pharmacological concentration of E2 can enhance the metastatic protential of human salivary gland mucoepidermoid carcinoma Mc3 cells.