Amphiregulin promotes trophoblast invasion and increases MMP9/TIMP1 ratio through ERK1/2 and Akt signal pathways.

The aim of our study is to illustrate the role of amphiregulin in trophoblast invasiveness and underlying signal cascades. An immortalized human early extravillous cell line, HTR-8/SVneo, was used for this investigation. Matrigel-transwell invasion assay was used for testing the effects of amphiregulin on cell invasiveness. MMP9 and MMP2 mRNA expression level and activity were measured using Rt-qPCR and zymographic analysis. Cell signals involved in the invasion process were verified using western blot and specific inhibitors. Our results showed that amphiregulin could promote HTR-8/SVneo cell invasiveness without interfering cell proliferation, and significantly upregulate the expression of MMP9 and TIMP-1 mRNAs as well as the ratio of MMP9/TIMP-1. Using specific inhibitors for MEK and PI3K signaling further indicated that, both ERK1/2 and Akt signal pathways were required for amphiregulin-induced cell invasiveness. The co-ordination between ERK1/2 and Akt signaling pathway was needed for the upregulation of MMP9 mRNA, while ERK1/2 was more essential for the upregulation of TIMP-1 mRNA. Meanwhile, we first put forward that the deficiency of amphiregulin expression in trophoblast might be compensated by the upregulation of epidermal growth factor receptor (EGFR) and heparin-binding EGF (HB-EGF) mRNA. ERK1/2 and Akt signaling pathways mediate amphiregulin-induced upregulation of MMP9 mRNA and the MMP9/TIMP-1 ratio, which subsequently contribute to amphiregulin-promotion of HTR-8/SVneo cell invasion.