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

Aims: The aim of our study is to illustrate the role of amphiregulin in trophoblast invasiveness and underlying signal cascades. Main methods: 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. Key findings: 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. Significance: 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.