CARM1 is a downstream gene of RBM5 and is upregulated in bladder cancer (BC) tissues. (A) T24 cells were transfected with the LV−oeRBM5 lentivirus, and the gene expression profile was used to target the downstream genes of RBM5. The heat map shows the upregulated genes in red and the downregulated genes in blue. (B,C) T24 cells were transfected with LV−oeRBM5 and LV−Con, whereas J82 cells were transfected with LV−shRBM5 and LV−shCon. Subsequently, RT−qPCR was used to detect the mRNA expression of candidate genes. (D,E) T24 cells were transfected with LV−oeRBM5 and LV−Con, and western blotting was used to examine the CARM1 protein expression. (F,G) J82 cells were transfected with LV−shRBM5 and LV−shcon, and CARM1 protein expression was detected via western blotting. (H) Hematoxylin and eosin staining was used to analyze the normal bladder tissue and BC tissue. (I) The CARM1 expression in the normal bladder and BC tissues was detected via immunohistochemical staining. (J,K) The expression of CARM1 protein and mRNA was evaluated in normal and BC tissues via western blotting and RT−qPCR. (L) CARM1 mRNA expression was analyzed based on the data from The Cancer Genome Atlas (TCGA) database. (M) High CARM1 expression was associated with a poor prognosis and a low overall survival rate in patients with BC from the TCGA database. All data were derived from three independent experiments and expressed as the mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01, *** p < 0.001 vs. their corresponding controls.