Epidermal growth factor-like domain 7 promotes migration and invasion of human trophoblast cells through activation of MAPK, PI3K and NOTCH signaling pathways

Abstract

Epidermal growth factor-like domain 7 (Egfl7) is a gene that encodes a partially secreted protein and whose expression is largely restricted to the endothelia. We recently reported that EGFL7 is also expressed by trophoblast cells in mouse and human placentas. Here, we investigated the molecular pathways that are regulated by EGFL7 in trophoblast cells. Stable EGFL7 overexpression in a Jeg3 human choriocarcinoma cell line resulted in significantly increased cell migration and invasiveness, while cell proliferation was unaffected. Analysis of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways showed that EGFL7 promotes Jeg3 cell motility by activating both pathways. We show that EGFL7 activates the epidermal growth factor receptor (EGFR) in Jeg3 cells, resulting in downstream activation of extracellular regulated kinases (ERKs). In addition, we provide evidence that EGFL7-triggered migration of Jeg3 cells involves activation of NOTCH signaling. EGFL7 and NOTCH1 are co-expressed in Jeg3 cells, and blocking of NOTCH activation abrogates enhanced migration of Jeg3 cells overexpressing EGFL7. We also demonstrate that signaling through EGFR and NOTCH converged to mediate EGFL7 effects. Reduction of endogenous EGFL7 expression in Jeg3 cells significantly decreased cell migration. We further confirmed that EGFL7 stimulates cell migration by using primary human first trimester trophoblast (PTB) cells overexpressing EGFL7. In conclusion, our data suggest that in trophoblast cells, EGFL7 regulates cell migration and invasion by activating multiple signaling pathways. Our results provide a possible explanation for the correlation between reduced expression of EGFL7 and inadequate trophoblast invasion observed in placentopathies.

CCN1 (CYR61) and CCN3 (NOV) signaling drives human trophoblast cells into senescence and stimulates migration properties

“…In Jeg3 cells, epidermal growth factor-like domain 7 promotes migration and invasion by activating the MAPK, PI3K, and Notch pathways. 60 In contrast here, phosphorylation and activation of ERK1/2 do not seem to play a role in CCN1/3-mediated regulation of migration in SGHPL-5 cells, because the phosphorylation status remains unchanged after treatment with both CCN proteins.…”

Altered feto-placental vascularization, feto-placental malperfusion, and fetal growth restriction in mice with Egfl7 loss-of-function

“…Of note, we have recently reported novel sites of Egfl7 expression in junctional zone placental trophoblasts in mice and in cytotrophoblasts and syncytiotrophoblasts in human placentas, in addition to its expression in the fetal and maternal placental endothelium . In fact, EGFL7 in human cultured trophoblast cells promotes migration and invasion through activation of NOTCH and EGFR signaling pathways (Massimiani et al, 2015). Future studies using trophoblast-specific knockout or knockdown of Egfl7 will address the possibility of non-cell autonomous and non-endothelial effects on branching morphogenesis in the labyrinth.…”

“…Previous studies have shown that Egfl7 modulates Notch signaling in vivo in mouse embryos and in vitro in HUVECs, human trophoblast cells and neural stem cells (Nichol et al, 2010;Massimiani et al, 2015;Schmidt et al, 2009). To examine whether Egfl7 modulates Notch signaling in the developing placental labyrinth, we performed real time RT-PCR for Notch target genes in pre-placental tissues (E8.5) or placentas (E9.5, E12.5) from C57BL/6J control and Egfl7 −/− mice.…”

“…Egfl7 has been shown to promote migration of ECs and trophoblast cells (Campagnolo et al, 2005;Massimiani et al, 2015;Nichol et al, 2010). Its expression is downregulated in human pre-eclamptic placentas Junus et al, 2012), placentas of a mouse model of PE prior to the onset of clinical signs , and in plasma of individuals with pregnancies affected by intrauterine growth restriction (Zanello et al, 2013).…”

PREX2 promotes the proliferation, invasion and migration of pancreatic cancer cells by modulating the PI3K signaling pathway

“…Aberrant activation of PI3K signaling promotes cancer cell proliferation, invasion and migration (9)(10)(11). Phosphatase and tensin homolog (PTEN) is able to antagonize PI3K signaling, thus acting as an inhibitor of the PI3K signaling pathway (12).…”