Abstract
MicroRNAs (miRs) are potential therapeutic targets for tumors. The aims of the present study were to investigate the regulatory effects of miR‑34a on the proliferation, apoptosis and chemosensitivity of retinoblastoma (RB) cells, and to identify the possible underlying mechanism involving Notch1. It was found that miR‑34a was downregulated, and Notch1 was upregulated in HXO‑RB44 and Y79 cells. In addition, Notch1 was identified to be a target gene of miR‑34a, which could be downregulated by the increased expression of miR‑34a. It was demonstrated that miR‑34a upregulation and Notch1 downregulation significantly inhibited proliferation, promoted apoptosis and enhanced the carboplatin sensitivity of HXO‑RB44 and Y79 cells. The transfection of miR‑34a mimics + Notch1 siRNA further enhanced the above anti‑tumor responses in HXO‑RB44 and Y79 cells. Collectively, the present results suggested that miR‑34a may negatively regulate Notch1 expression and may be a potential therapeutic target for RB.