MicroRNA-497 accelerates apoptosis while inhibiting proliferation, migration, and invasion through negative regulation of the MAPK/ERK signaling pathway via RAF-1.

Abstract

The aim of this study is to explore the various modes of action miR-497 has on human cervical cancer (CC) cell behavior. We also speculate that miR-497 achieves its anti-tumor role by governing RAF-1 via MAPK/ERK signaling pathway. CC tissues with corresponding adjacent normal tissues were collected from 168 CC patients. RAF-1-positive cells were identified by means of immunohistochemistry in tissues. A series of inhibitors, mimics and siRNA against RAF-1 were introduced to validate regulatory mechanisms for miR-497 and RAF-1. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assay were employed for evaluating alternations of miR-497, RAF-1, and MAPK/ERK signaling pathway. HeLa cell proliferation, invasion, migration, cycle progression, and apoptosis were assessed by means of CCK-8, wound-healing, transwell invasion assays, and flow cytometry, respectively. The target prediction program and luciferase activity determination were used to identify miR-497 targeting RAF-1. We determined reduced miR-497 expression and elevated expression of RAF-1 in CC tissues as opposed to adjacent tissues. Transfection of miR-497 mimics and siRNA-RAF-1 both decreased levels of MEK1, ERK1, and p38 phosphorylation in HeLa cells, inhibited cell proliferation, migration and invasion, induced more cells arrested in the G0/G1 phase, and promoted cell apoptosis; while miR-497 inhibitors led to opposite results. These findings indicate miR-497 as a tumor suppressor results from negative regulation of the MAPK/ERK signaling pathway via RAF-1 in CC.