MicroRNA-216b/Beclin 1 Axis Regulates Autophagy And Apoptosis In Human Tenon’s Capsule Fibroblasts Upon Hydroxycamptothecin Exposure

Purpose Treatment of antitumor drug can lead to different cell fates, autophagy or apoptosis. This study aims to determine the autophagy and apoptosis in human Tenon’s capsule fibroblasts (HTFs) in responding to treatment with the hydroxycamptothecin (HCPT), and dissect the regulatory pathway.Methods Autophagic activity was determined by mRFP-GFP-LC3 transfection assay and Cyto-ID Green staining. Apoptosis was evaluated by cell viability assay and Annexin V/Propidium Iodide dual staining. Proteins associated with autophagy and apoptosis were examined by western blot. Altered expressions of micro-RNAs in HTFs after treatment with HCPT were determined by microarray and validated by quantitative reverse transcriptase Polymerase Chain Reaction. miRNAs-targeting genes associated with autophagy were predicted using three on-line programs and confirmed by luciferase assay and western blot.Results HCPT induced significant autophagy and down-regulated the expression of miR-216b in HTFs. While over expressing miR-216b suppressed the autophagy and apoptosis induced by HCPT, silencing miR-216b led to similar effects as those caused by HCPT. Furthermore, knocking down Beclin-1, a direct target of miR-216b, significantly decreased HCPT-triggered autophagy and apoptosis, and increased the viability of HTFs treated with HCPT.Conclusions We concluded that miR-216b regulated both autophagy and apoptosis by modulating Beclin 1 in HTFs treated with HCPT. We also demonstrated that HCPT-induced autophagy is one of the agent’s anti-proliferative effects.