Fig. 5

LncRNA BCRT1 promoted breast cancer cell proliferation and progression by protecting PTBP3 from miR-1303-induced degradation. a Schematic illustration showing the overlapping target genes of miR-1303 predicted by miRDB, miRWalk, miRPathDB, and TargetScan. b The expression of PTBP3 was increased in breast cancer tissues compared to normal tissues based on the TCGA and GEO databases. c RT-PCR revealed a positive correlation between lncRNA BCRT1 expression and PTBP3 expression in breast cancer cells. d The upper schematic diagram represents the construction of the luciferase reporter plasmids. The lower panel shows the predicted and the mutated binding sites of miR-1303 in the 3′UTR of PTBP3. The statistical graphs on the right show the luciferase activity in HEK293T cells with or without miR-1303 overexpression and transfected with the WT or MUT luciferase plasmids. e RT-PCR and western blot assays revealed the effect of miR-1303 on PTBP3 expression. f RT-PCR and western blot assays showed that lncRNA BCRT1 knockdown repressed the expression of PTBP3. g RT-PCR and western blot assays were used to determine the PTBP3 expression level in MDA-MB-231 cells cotransfected with pcDNA3.1-BCRT1 and miR-1303 mimics. h RT-PCR was used to detect the efficiency of PTBP3 knockdown in breast cancer cells. i MTT assay was performed to examine the proliferation ability after PTBP3 knockdown. j PTBP3 knockdown led to increased cell apoptosis. k Transwell assays revealed that PTBP3 knockdown inhibited the migration and invasion abilities of breast cancer cells. (*P < 0.05, **P < 0.01, and ***P < 0.001)