Muscle-invasive bladder cancer (MIBC) is an aggressive form of urothelial bladder carcinoma (UBC) with poorer outcomes compared to the non-muscle invasive form (NMIBC). Higher recurrent rates and rapid progression after relapse in UBC is known to be linked with chronic inflammation. Here, the preclinical murine models of NMIBC (MB49) and MIBC (MB49-I) were used to assess the antitumor effects of DAB-1, an anti-inflammatory aminobenzoic acid derivative we have developed in order to target cancer-related inflammation. A subchronic toxicity study on cancer-free mice shown that DAB-1 treatment did not affect normal mouse development or normal function of vital organs. In mice bearing MB49-I tumors, whole body accumulation of the radioconjugate [131I]DAB-1 was higher than in control mice, the main sites of [131I]DAB-1 accumulation being the liver (34%), the intestines (21%), and the tumors (18%). In vivo molecular therapy of ectopic and orthotopic tumors indicated that treatment with DAB-1 efficiently inhibited tumor growth, metastasis formation, and mortality rate. The antitumor efficacy of DAB-1 was associated with strong decreased tumor cell proliferation and iNOS expression in tumor tissues and deactivation of macrophages from tumor-bearing mice. Mechanistic investigations revealed that DAB-1 efficiently inhibited i) TNFα/NFΚB and IL6/STAT3 signaling pathways activation; ii) TNFα-induced NO production by decreasing NFΚB transcriptional activation and functional iNOS expression; and iii) cellular proliferation with minimal or no effects on cell mortality or apoptosis. In conclusion, this study provides preclinical and biological/mechanistic data highlighting the potential of DAB-1 as a safe and efficient therapeutic agent for the treatment of patients with NMIBC and MIBC.
Keywords: Bladder cancer; Cancer-related inflammation; Inducible nitric oxide synthase; Nuclear factor kappa B; Tumor necrosis factor alpha.
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