ZEB1 modulates endometrial receptivity through epithelial-mesenchymal transition in endometrial epithelial cells in vitro.

Zinc finger E-box binding homeobox 1 (ZEB1) promotes epithelial-mesenchymal transition (EMT) in carcinogenesis, but its role in embryo implantation has not yet been identified. The present study sought to verify if ZEB1 plays a role in endometrial receptivity through regulation of EMT during embryo implantation. Endometrial epithelium from sixty patients in phase of the menstrual cycle (including proliferative and secretory phases) were collected for assessment of mRNA/protein expression. In human endometrial adenocarcinoma cell line RL95-2, ZEB1 expression was suppressed by using shRNA, and the cell function and mRNA/protein expression were evaluated. RL95-2 cells and human choriocarcinoma cell line JAR were co-cultured to establish embryo implantation model in vitro. The results showed that, ZEB1 was highly expressed at both mRNA and protein levels in human endometrium during mid-secretory phase of the menstrual cycle. Knockdown of ZEB1 expression in RL95-2 cells attenuated cell growth, migration, DNA replication, and altered expression of E-cadherin and vimentin at both mRNA and protein levels. Interestingly, knockdown of ZEB1 expression in RL95-2 cells potently suppressed JAR spheroid attachment in vitro (P < 0.01). Additionally, the. Conclusively, knockdown of ZEB1 suppressed embryo implantation in vitro, paralleled with alteration of EMT markers. ZEB1 is likely to modulate endometrial receptivity through promotion of EMT, that could be crucial for embryo implantation process.