miR-512-3p Overcomes Resistance to Cisplatin in Retinoblastoma by Promoting Apoptosis Induced by Endoplasmic Reticulum Stress

BACKGROUND Retinoblastoma (RB) seriously endangers the vision and even the life of patients. This study aimed to explore the endoplasmic reticulum stress (ERS) and drug resistance of RB and verify the effect of miR-512-3p as a regulator of XBP-1 shearing mechanism on ERS, proliferation, apoptosis, and autophagy levels of RB cells. MATERIAL AND METHODS Y79, weri-RB1, and HXO-RB44 cells were treated with cisplatin (DDP) gradient concentration to construct DDP-resistant cells. The drug inhibition rate and cell proliferation were assessed by CCK-8 assay. The cell transfection and cell apoptosis were detected by RT-qPCR analysis and TUNEL assay, respectively. The protein expression was detected by Western blot analysis. Dual-luciferase reporter assay confirmed the combination of miR-512-30p and XBP-1 transcript 1/2. RESULTS DDP inhibition rates for DDP-resistant RB cells were lower than that for RB cells. The XBP-1 expression was increased in DDP-resistant RB cells, and Y79 cells were chosen for the subsequent experiments. After transfection, miR-512-3p overexpression obviously inhibited the proliferation of DDP-resistant Y79 cells (Y79/DDP cells). miR-512-3p overexpression increased the DDP inhibition rate for Y79/DDP cells and apoptosis of Y79/DDP cells. miR-512-3p overexpression downregulated the expression of LC3 II/I in Y79/DDP cells. The effect of miR-512-3p inhibition on Y79/DDP cells was not as obvious as the effect of miR-512-3p overexpression on Y79/DDP cells. Furthermore, miR-512-3p was confirmed to be combined with XBP-1 transcript variant 1. CONCLUSIONS miR-512-3p improved the DDP resistance of RB cells by promoting ERS-induced apoptosis and inhibiting the proliferation and autophagy of RB cells.