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Stroma-tumor communication participates in the pathogenesis of endometrial carcinomas. In previous studies, we found that normal stromal cells inhibited the growth of endometrial carcinoma cells. Here, we investigated the role of normal stromal cells in the epithelial-mesenchymal transition (EMT) of endometrial carcinoma cells and explored the possible mechanism implied. We found that conditioned medium (CM) by normal endometrial stromal cells (NSC) reduced cell growth and induced cell apoptosis in Ishikawa cells. CM by NSC inhibited 17β-estradiol-induced cell growth and apoptosis decrease in Ishikawa cells. Moreover, CM by NSC inhibited the migration and invasion, and 17β-estradiol-induced migration and invasion in Ishikawa cells. Meanwhile, CM by NSC decreased Slug expression and 17β-estradiol-induced Slug expression, increased E-cadherin expression and abolished 17β-estradiol-induced E-cadherin reduction in Ishikawa cells. In conclusion, normal stromal factors can inhibit 17β-estradiol-induced cell proliferation and apoptosis inhibition, and abolished 17β-estradiol-induced EMT in endometrial cancer cell via regulating E-cadherin and Slug expression.

Objective: Stroma-tumor communication plays an important role in the genesis of neoplasia. In the current study, we investigated the effect of normal stromal cells on the survival and apoptosis signaling of endometrial cancer cells and further explored the possible mechanism implied in this communication., Methods: Using primarily cultured normal endometrial stromal cells and an endometrial adenocarcinoma cell line, Ishikawa cells, we established a 2D-coculture system to observe the stromal cell-tumor cell crosstalk in endometrial carcinomas. Using methyl thiazolyl tetrazolium (MTT) assays, cell counting and colony formation assays, we analyzed the effect of stomal cells on the growth and proliferation of Ishikawa cells under different conditions. Using western blot analysis, we determined the effect of stromal cells on the activity of PI3K/AKt/Survivin signaling in Ishikawa cells under different conditions. Using immunohistochemistry analysis, we determined the expression of Survivin in normal endometria and endometrial adenocarcinomas., Results: We found that the paracrine factors from normal endometrial stromal cells grown on Matrigel repeatedly and significantly decreased hormone-stimulated activity of PI3K/AKt/Survivin signaling in Ishikawa cells, which were proved to be increased in endometrial adenocarcinoma and essential in hormone-induced cell growth in Ishikawa cells., Conclusion: Paracrine factors from normal endometrial stromal cells can inhibit hormone-stimulated cell proliferation in Ishikawa cells by regulating cell survival and apoptosis through PI3K/AKt/Survivin signaling., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Abstract: Dual-specificity phosphatase 6 (Dusp6) is a negative feedback mechanism of fibroblast growth factors (FGFs)/mitogen-activated protein kinase (MAPK)/ERK1/2 signaling. The aim of this study was to explore the expression of Dusp6 in human endometrial adenocarcinomas and the role of Dusp6 expression in the growth regulation of endometrial adenocarcinoma cell. We found that Dusp6 was over-expressed in human endometrial adenocarcinomas. In Ishikawa cells, plasmid-driven Dusp6 expression efficiently blocked the activity of FGF2-induced MAPK/ERK1/2 signaling. Unexpectedly, Dusp6 expression significantly enhanced the growth of Ishikawa cells. In Dusp6 forced-expression cells, 17β-estradiol stimulation increased the cell growth by all most threefolds. In addition, progesterone treatment reduced the cell growth to about half both in Ishikawa cells with and without forced-Dusp6-expression. Dusp6 over-expression is involved in the pathogenesis and development of human endometrial adenocarcinomas. Dusp6 functions as a negative regulator of FGF2/ERK1/2 signaling but enhances the growth and 17β-estradiol-induced cell growth in endometrial adenocarcinoma cell. [Copyright &y& Elsevier]