RT Journal Article SR Electronic T1 Altered Claudin-4 Expression in Progesterone-Treated Endometrial Adenocarcinoma Cell Line Ishikawa JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP 1585 OP 1590 DO 10.1097/IGC.0b013e318272ab12 VO 22 IS 9 A1 Xiao-Yu, Pan A1 Yan, Jin A1 Cui-Ping, Feng A1 Ya-Nan, Wang A1 Hua, Lin A1 Hua-Jun, L YR 2012 UL http://ijgc.bmj.com/content/22/9/1585.abstract AB Objective To detect the expression change of claudin-4 in Ishikawa endometrial adenocarcinoma cell line in response to progesterone. To determine whether claudin-4 is involved in the anticancer effect of progesterone.Methods 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the 50% inhibitory concentration (IC50) of megestrol acetate (MA) in treating Ishikawa cells. After the Ishikawa cells were treated with MA at IC50, cell apoptosis was examined by flow cytometry and transmission electron microscopy. The messenger RNA and protein expression levels of claudin-4 were further quantified by real-time polymerase chain reaction and Western blot. The localization of claudin-4 was examined by immunofluorescent staining.Results The IC50 of MA on Ishikawa cells was 15 mg/L incubated for 72 hours. Apoptosis percentage was elevated from 0.07% ± 0.02% to 3.93% ± 0.81% after MA treatment. The expression of claudin-4 at both protein and messenger RNA levels was significantly decreased after the treatment of MA (P < 0.05). The localization of claudin-4 transferred from cytomembrane to cytoplasm and nucleus.Conclusion Megestrol acetate can inhibit the growth of Ishikawa cells. It may work through decreasing claudin-4 expression and cell apoptosis. The localization change of claudin-4 may also be involved in the anticancer effect of progesterone.