Identification of ATP-sensitive K+ Channel in an Uterine Leiomyoma Cell

Objective : The purpose of this study was to identify the ATP-sensitive potassium (K) channel subtypes in uterine leiomyoma and normal myometrial cells, and to compare the difference in its expression between uterine leiomyoma and normal myometrial cells. Methods : Fresh ten uterine leiomyomas and their adjacent normal myometrial tissues were obtained from hysterectomies that were conducted on benign diseases. With the use of reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis, we analysed the expression of K channel subtypes in tissues and primary cultured leiomyoma cells. To demonstrate the K channel activity in uterine leiomyoma cells, whole cell patch-clamp recordings were made. Results : The uterine leiomyoma and normal myometrial tissues contained Kir6.1/SUR2B and Kir6.2/ SUR2B mRNAs, although the expression of SUR1 and SUR2A mRNAs were not expressed in the uterine leiomyoma and normal myometrial tissues. Primary cultured uterine leiomyoma and normal myometrial cells demonstrated same patterns. To determine the expression levels of K channel subunits, high levels of Kir6.1, Kir6.2, and SUR2B were detected by western-blot analysis in uterine leiomyoma compared with normal myometrial tissues. K channel currents were increased by estrogen application in uterine leiomyoma cells. Conclusion : These studies provide new knowledge concerning K channels in uterine leiomyoma and normal myomtrial cells. we demonstrated uterine leiomyoma and normal myometrial tissues contained Kir6.1/ SUR2B and Kir6.2/SUR2B subunits and showed an increased expression in uterine leiomyoma compared with normal myometrial tissues. These results suggest that K channels are important elements in growth of uterine leiomyoma.