AbstractEmerging evidence has manifested that long non-coding RNAs (lncRNAs) played critical roles in diabetes. The present research aimed to investigate the role and mechanism of XIST on proliferation, migration and apoptosis in diabetic cataract (DC). In the present study, lens epithelial cells (SRA01/04) were treated by high glucose (HG). The levels of XIST, miR-34a and SMAD2 were examined by RT-qPCR. MTT, transwell, wound healing and TUNEL assays were employed to examine cell proliferation, invasion, migration and apoptosis. The interaction between miR-34a and XIST or SMAD2 was verified by luciferase reporter assay. It was found that XIST expression was increased and miR-34a level was decreased in DC tissues and HG-induced SRA01/04 cells. XIST knockdown or miR-34a addition attenuated cell proliferation and migration, and induced apoptosis in SRA01/04 cells under HG. XIST targeted miR-34a and regulated DC progression via miR-34a. SMAD2 was a target gene of miR-34a and was positively modulated by XIST. SMAD2 addition accelerated cell proliferation, migration and inhibited the apoptosis in HG-stimulated SRA01/04 cells, which were abrogated by XIST depletion. In conclusion, XIST facilitated the proliferation, migration and invasion, and inhibited the apoptosis via miR-34a/SMAD2 axis in DC.