Intravesical Instillation of Azacitidine Suppresses Tumor Formation through TNF-R1 and TRAIL-R2 Signaling in Genotoxic Carcinogen-Induced Bladder Cancer

Abstract

Azacitidine, an inhibitor of DNA methylation, shows therapeutic effects against several malignancies by inducing apoptosis and inhibiting tumor cell proliferation. However, the anti-tumor effects of azacitidine on urinary bladder urothelial carcinoma (UBUC), especially following intravesical instillation (IVI), are not established. Here, UBUC cell lines were used to analyze the in vitro therapeutic effects of azacitidine. Potential signaling pathways were investigated by antibody arrays and Western blotting. The N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced rat UBUC model was used for in vivo quantitative analysis of tumor burden. Azacitidine significantly inhibited DNMT expression in UBUC cell lines and reduced cell viability and clonogenic activity, as determined by MTT and colony formation assays, while also inducing significant cytotoxic effects in the form of increased sub-G1 and Annexin V-PI populations (all p p < 0.01). Our study provides evidence for a reduction in BBN-induced bladder cancer by IVI of azacitidine through alterations in the TRAIL-R2 and TNF-R1 signaling pathways. These findings might provide new insights for further clinical trials.

Keywords

• bladder cancer
• azacitidine
• intravesical instillation
• TNF-R1
• TRAIL-R2