323 Estrogen-Induced Epithelial-Mesenchymal Transition and Expression of Proapoptotic Markers in Porcine Stem Cells

Abstract

In transgenic pig production for generating animal models of human diseases, apoptosis of early implantation embryo disturbs the transgenic pig production. In general, epithelial-mesenchymal transition (EMT) is considered important in embryo development and apoptosis. In addition, it was reported that 17β-oestradiol (E2), among hormones that participate in early implantation of embryo, could induce EMT and neural differentiation in mouse embryonic stem cells. Therefore, in this study, we examined the effects of the steroid hormone, E2, in the changes of EMT and apoptotic markers in porcine embryonic stem cells (pESC) and porcine induced pluripotent stem cells (piPSC). During the study, we cultured pESC and piPSC in pESC media containing basic fibroblast growth factor (b-FGF) and leukemia inhibitory factor (LIF) and performed RT-PCR and an alkaline phophatase (AP) test to measure pluripotent and undifferentiation markers of these porcine stem cells. The RT-PCR results showed that OCT4, NANOG, and SOX2 were expressed in these pESC and piPSC, indicating their pluripotency as stem cells. Also, these porcine stem cells showed positive AP activity, demonstrating undifferentiation. Additionally, we treated pESC and piPSC with E2 to examine effects of steroid hormone on the changes of EMT and apoptotic markers (i.e. bcl-2, bax, E-cad, and vimentin). The E2 treatment increased the expression of vimentin and bcl-2, while decreased the expression of E-cadherin and bax. By using immunocytochemistry (ICC), we examined the protein expression of EMT markers, which are vimentin and E-cadherin at the translational level, and found that expression of vimentin protein was increased while E-cadherin protein level was reduced at periphery of the colonies in pESC and piPSC. In conclusion, these results indicate that E2 can promote EMT process and reverse apoptosis in these pESC and iPSC. In a future study, we will further examine the effects of progesterone on the expressions of EMT and apoptotic markers in pESC and piPSC. Consequently, this study will contribute to elucidate the underlying mechanisms of EMT and apoptosis controlled by steroid hormones in porcine stem cells.

Periostin and implantation: a new biomarker of embryo-endometrial cross talk

“…The EMT mechanism, proved to be effective for the metastatic niche creation, was found to play a pivotal role in embryo development and implantation too (18). Recently, Kim et al (56) using a porcine animal model, elucidate the underlying mechanism of EMT that was found to be controlled by steroid hormones. Besides to the action integrins-mediated, POSTN can directly interact with the other ECM proteins.…”

“…Since experimental data found that the activation of EMT programs in epithelial cells correlates with the appearance of stemness, authors suggested that the EMT process also leads the initial cancer cell colonization at distant sites (56). It is quite obvious that EMT reverse program, also called MET, is required for efficient metastatic colonization (56). As a matter of fact, EMT allows cancer cells to increase their motility and invasiveness properties allowing these cells to leave the primary epithelial tumor site.…”

“…More recently, EMT has been shown to be a very efficient strategy adopted by epithelial cancer cells to promote local invasion and dissemination at distant organs. Since experimental data found that the activation of EMT programs in epithelial cells correlates with the appearance of stemness, authors suggested that the EMT process also leads the initial cancer cell colonization at distant sites (56). It is quite obvious that EMT reverse program, also called MET, is required for efficient metastatic colonization (56).…”