Let-7 inhibits the migration and invasion of extravillous trophoblast cell via targeting MDM4

Abstract

Aims: Extravillous trophoblast (EVT) cells migration and invasion are important causes to preeclampsia (PE). Studies have shown that let-7 was involved in inhibiting proliferation and invasion of several cancer cells, however, its effect on EVT cells migration and invasion has hardly been reported. This study aimed to explore the relation between let-7 and EVT cell migration and invasion.

Methods: MicroRNA (miRNA) and genes expression levels were measured by reverse transcription polymerase chain reaction (RT-PCR) and Western blot (WB). Cell proliferation, migration and invasion were detected by cell counting kit-8 (CCK-8) assay, wound-healing assay and transwell assay. The binding site between let-7 and murine double minute 4 (MDM4) was identified using TargetScan. The targeting relation between let-7 and MDM4 was verified using dual luciferase reporter assay.

Results: The results revealed that in placental tissues of PE patients, let-7, matrix metalloproteinase-2 (MMP-2) and MMP-9 were lowly expressed and tissue inhibitors of metalloproteinase-1 (TIMP-1) and TIMP-2 were highly expressed. Let-7 silencing promoted the proliferation, migration, invasion of HTR8/SVneo cells and the expression levels of MMP-2 and MMP-9, however, it inhibited TIMP-1 and TIMP-2 expression levels, while overexpression of let-7 produced the opposite results. Furthermore, MDM4 is a target gene of let-7. Rescue experiments suggested that MDM4 siRNA partially reversed the effects of let-7 silencing on cells.

Conclusions: Let-7 silencing promoted proliferation, migration and invasion in EVT cells through the up-regulation of MDM4. Our study provided new insights into the molecular mechanism of PE.

Keywords: Extravillous trophoblast; Invasion; Let-7; Migration; Murine double minute 4.