Upregulation of miR-212-3p weakened KCNQ1OT1 roles in cell proliferation and apoptosis. (A) KCNQ1OT1 contents in nuclear and cytoplasm of SKOV3 and OVCAR3 cells were detected by qPCR assay (**, ##p < 0.01). (B) Luciferase gene reporter assay was used to detect the relationship between KCNQ1OT1 and miR-212-3p in SKOV3 cells (WT, wide type; MUT, mutant type). (C) Expression of miR-212-3p was detected by qPCR in the complex pulled down by biotinylated KCNQ1OT1. *p < 0.05. Then the following assays were carried out after cells were transfected with OE-KCNQ1OT1 or OE-KCNQ1OT1 + mimics. (D, E) MTT assay was performed to detect cell proliferation. (F) Transwell chambers were used to detect cell invasion ability. (G, H) Wound healing assay was used to detect cell migration. (I) Flow cytometry assay was used to detect cell apoptosis. (B–I) *p < 0.05, OE-KCNQ1OT1 group versus control group; #p < 0.05, OE-KCNQ1OT1 + mimic group versus OE-KCNQ1OT1 group.