Abstract: Objective：To study the mechanism on extracellular signal-regulate kinases (ERK) signal transduction by calcium influx initiated by combination of  estrogen with calcium channels or estrogen receptor in endometrial cancer cell Ishikawa. Methods: Confocal test was used to determine the relative calcium mobilization by stimulation of estrodiol together with and without the inhibition of ICI182780 and nifedipine. Western-blotting was used to detect the protein expression of phosphorylated ERK1/2(P-ERK1/2) in the same condition. Results: The transient calcium flux initiated by 17β-estrodiol (E2) and a membrane-impermeable conjugate of estrogen and bovine serum albumin (E2-BSA), and the calcium mobilization could be inhibited by ICI182780 and nifedipine in 1 min. In Ishikawa cells, phosphorylation of ERK1/2 was stimulated by E2, and the phosphorylation could not be inhibited by E2 after the combination with ICI182780 in 5 min and in 30 min. The phosphorylation also could not be inhibited by E2-BSA after the combination with nifedipine in 5 min, but in 30 min the phosphorylation was decreased. The phosphorylation of ERK by E2-BSA was decreased by the combination with nifedipine in 30 min. Conclusion: The transient calcium flux initiated by estrogen has an effect on the activation of ERK signal pathway in endometrial carcinoma cells.

Key words: Endometrial neoplasms, Calcium, Extracellular signal-regulated MAP kinases, Estrogens