During the first trimester of pregnancy, trophoblastic E-cadherin expression is down-regulated, thereby allowing extravillous trophoblasts (EVTs) to acquire the potential for migration and invasiveness. The aim of the present study was to investigate the role of OSM on the migration and proliferation of EVT cell line HTR8/SVneo with regard to its effects on the expression of E-cadherin and STAT3 activation.
We investigated the effects of OSM on RNA and protein expression of E-cadherin by real time RT-PCR analyses, western blotting, and indirect immunofluorescence staining in HTR8/SVneo cells, as well as the effects on cell migration and proliferation. The selective signal transducer and activator of transcription (STAT)3 inhibitor, stattic, and STAT3 siRNA were used to investigate STAT3 activation by OSM.
OSM significantly reduced RNA and protein expression of E-cadherin. Indirect immunofluorescence staining of HTR8/SVneo cells also revealed the down-regulation of E-cadherin, compared with the controls. OSM-stimulated cell migration was attenuated by anti-gp130 antibodies. OSM-induced STAT3 phosphorylation, and the down-regulation of E-cadherin by OSM treatment was restored by stattic and STAT3 siRNA. In addition, OSM-stimulated migration and proliferation were significantly suppressed by STAT3 inhibition.
This study suggests that OSM stimulates the migration and proliferation of EVTs during the first trimester of pregnancy through the down-regulation of E-cadherin. In addition, this study suggests that the effects of OSM on migration and proliferation are related to STAT3 activation, which is important in trophoblast invasiveness.