Identification of Estrogen Response Element in the Aquaporin-2 Gene That Mediates Estrogen-Induced Cell Migration and Invasion in Human Endometrial Carcinoma

Background: Accumulating evidence suggests that aquaporins (AQP) can facilitate cell migration, invasion, and proliferation in tumor development in addition to water transport. Objective: The aim of this study was to examine AQP2 expression in the endometrial tissues from patients with endometrial carcinoma (EC) and determine the roles and mechanisms of AQP2 in estrogen-related cell migration, invasion, adhesion, and proliferation of Ishikawa (IK) cells. Approach: AQP2 expression levels were measured in human endometrial cells and estradiol (E2)-treated IK cells, and the estrogen-response element was identified. After blocking down and up-regulating the endogenous expression of AQP2 in IK cells, cell morphology, capacity for invasion, migration and adhesion, and expression markers of membrane/cytoskeleton were analyzed. Results: AQP2 was expressed in endometrial tissues from patients with EC and endometriosis, both of which are estrogen-dependent diseases. In IK cells, E2 dose-dependently increased AQP2 e...