Evaluation of Benzenesulfonamide Derivatives; Quinazoline and Sulfonamide Selectively Targeting Carbonic Anhydrase XII for Tumor Microenvironment Modulation in Human Breast Cancer Cells

Tumor cells evolve adaptive mechanisms to function optimally within an acidic microenvironment. This adaptation is driven by the enhanced metabolic activity of tumors, which frequently results in acidosis and hypoxia. Carbonic anhydrase enzymes orchestrate cell homeostasis and affect cancer cell fate. Advances in structure-based design have enabled the identification of selective carbonic anhydrase XII inhibitors. The study aimed to evaluate the anti-proliferative activity of sulfonamide derivatives and elucidate the plausible mode of action. MTT assay was conducted to evaluate cytotoxicity of acetazolamide, parent C3 and its derivatives C4 and C6 against breast cancer cell lines MCF-7, MDA-MB-231 and prostate cancer cells PC3. Further studies for C3, C4 and C6 compounds were conducted against MCF-7. Enzyme-linked immunosorbent assay of carbonic anhydrases IX and XII and fluorescent intracellular pH assay were conducted. Investigated compounds and acetazolamide reduced proliferation of all tested cells after 72 h. C3, C4, and C6 compounds reduced carbonic anhydrase XII concentrations. C3 and C6 did not appear significant reduction in CAIX in MCF-7. Conversely, C4 displayed statistically significant increase. Cells exposed to C3, C4, and C6 revealed a decrease in intracellular pH levels. In conclusion, all three compounds exhibited antiproliferative activities characterized by modulation of tumor pHi/pHe.