High expression of miR-204-5p promotes malignant behaviors of bladder cancer cells by negatively regulating RAB22A

Objective: To explore the regulatory effect of miR-204-5p on biological behaviors of bladder cancer cells and its molecular mechanism.

Methods: Survival analysis and correlation analysis were performed using TCGA database to explore the association of miR-204-5p expression with survival outcomes and clinicopathological parameters of bladder cancer patients. The expression level of miR-204-5p was detected in bladder cancer and adjacent tissues and in normal uroepithelial cells and bladder cancer cells. In cultured bladder cancer cells, the effects of miR-204-5p overexpression and knockdown on cell proliferation, migration, invasion, and apoptosis were analyzed. Transcriptome sequencing, bioinformatics analysis and dual-luciferase assay were carried out to confirm targeted inhibition of RAB22A by miR-204-5p to promote malignant biological behaviors of bladder cancer cells.

Results: Patients with high miR-204-5p expressions had lowered median survival time and poor prognosis (P < 0.05). The expression of miR-204-5p was significantly up-regulated in bladder cancer tissues and cells (P < 0.05). In bladder cancer cells, miR-204-5p overexpression significantly promoted cell proliferation, migration and invasion and reduced cell apoptosis. Transcriptome sequencing, bioinformatics analysis and dual-luciferase assay all suggested that RAB22A was a key downstream factor of miR-204-5p. Overexpression of miR-204-5p significantly inhibited RAB22A expression in bladder cancer cells, and overexpression of RAB22A partially reversed miR-204-5p overexpression-induced enhancement of bladder cancer cell proliferation.

Conclusions: High expression of miR-204-5p promotes proliferation, migration and invasion and reduces apoptosis of bladder cancer cells by negatively regulating RAB22A expression.