MiR-148b functions as a tumor suppressor by targeting endoplasmic reticulum metallo protease 1 in human endometrial cancer cells.

This study was aimed to investigate the tumor suppressive role of miR-148b in regulating endoplasmic reticulum metalloprotease 1 (ERMP1) expression and oxidative stress response in endometrial cancer cells. Human endometrial cancer RL95-2 cells were used and transfected with miR-148b mimic, miR-148b inhibitor, and their scrambled negative control. Thereafter, the transfection efficiency was determined by qRT-PCR and cell viability was assessed by MTT assay. The luciferase reporter assay, Western blot, and qRT-PCR were conducted to determine the target gene of miR-148b. ERMP1 might be the target of miR148b and thereby the over-expression and down-regulation of ERMP1 on proliferation of RL95-2 cells were assessed. Next, the expression of hypoxia-inducible factor 1 (HIF-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) were analyzed by Western blot. Intracellular reactive oxygen species (ROS) was determined using dichlorofluorescin diacetate (DCFDA). Results showed that differential expression of miR-148b or ERMP1 was observed in normal endometrial tissues and endometrial cancerous tissues. Enhanced expression of miR-148b effectively inhibited viability of RL95-2 cells. ERMP1 was the target of miR-148b. ERMP1 silence obviously suppressed proliferation of RL95-2 cells. Thus, miR-148b repressed cell proliferation likely through down-regulating ERMP1. Furthermore, it was observed that miR-148b significantly decreased expression of HIF1 and Nrf-2 by down-regulating ERMP1. The intracellular ROS level was enhanced by miR-148b via down-regulating ERMP1. To concluded, our results suggested that miR-148b suppressed cell proliferation and regulated oxidative stress response in human endometrial cancer RL95-2 cells by inhibiting ERMP1.