Re-establishment of gap junctional intercellular communication (GJIC) between human endometrial carcinomas by prostaglandin E(2)

Prostaglandin E2 Enhances Gap Junctional Intercellular Communication in Clonal Epithelial Cells

Prostaglandins are a group of lipids that produce diverse physiological and pathological effects. Among them, prostaglandin E2 (PGE2) stands out for the wide variety of functions in which it participates. To date, there is little information about the influence of PGE2 on gap junctional intercellular communication (GJIC) in any type of tissue, including epithelia. In this work, we set out to determine whether PGE2 influences GJIC in epithelial cells (MDCK cells). To this end, we performed dye (Lucifer yellow) transfer assays to compare GJIC of MDCK cells treated with PGE2 and untreated cells. Our results indicated that (1) PGE2 induces a statistically significant increase in GJIC from 100 nM and from 15 min after its addition to the medium, (2) such effect does not require the synthesis of new mRNA or proteins subunits but rather trafficking of subunits already synthesized, and (3) such effect is mediated by the E2 receptor, which, in turn, triggers a signaling pathway that includes activation of adenylyl cyclase and protein kinase A (PKA). These results widen the knowledge regarding modulation of gap junctional intercellular communication by prostaglandins.

Normal endometrial stromal cells regulate 17β-estradiol-induced epithelial-mesenchymal transition via slug and E-cadherin in endometrial adenocarcinoma cells in vitro

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.