Prostaglandin F stimulates adhesion, migration, invasion and proliferation of the human trophoblast cell line HTR-8/SVneo.

INTRODUCTION

The amount of prostaglandin F (PGF) in the uterine lumen increases during the window of implantation in many mammals, including humans. We hypothesized that PGF regulates processes related to human embryo implantation.

METHODS

The effect of PGF was studied using an in vitro model of human extravillous trophoblast (EVT) cell line (HTR-8/SVneo). Adhesion, proliferation, invasion and migration assays, zymography for metalloproteinases (MMP) activity, and gene/protein expression analyses were applied. Doses of 100 nM and/or 1 μM of PGF and fluprostenol were used. PGF receptor (PTGFR), MMP9 and MMP2 proteins in the human first trimester placenta were localized by immunohistochemistry and immunofluorescence.

RESULTS

This study is the first reporting the expression of PTGFR protein in the first trimester placenta, as well as in HTR-8/SVneo cells. PGF and fluprostenol increased HTR-8/SVneo cell proliferation and adhesion to extracellular matrix protein (P < 0.05). This effect was abolished by mitogen activated protein kinases (MAPK) inhibitor. PGF induced phosphorylation of focal adhesion kinase and MAPK1/3 (P < 0.05). PGF increased mRNA content and protein activity of MMP9, and gene and protein expression of interleukin-6 (P < 0.05). EVT cell migration and invasiveness were stimulated by PGF (P < 0.05). The PGF effect on cell invasion was reduced by inhibitors of MMP2, MMP9 and mTOR. In all experiments, the stimulatory effects of PGF were diminished by using a PTGFR antagonist.

DISCUSSION

Our findings suggest a significant role for PGF in mechanisms associated with implantation. PGF acting by PTGFR in HTR-8/SVneo cells stimulates their adhesion and proliferation through the MAPK signaling pathway and increases invasiveness inducing MMP proteolytic activity and mTOR signaling.