Novel sulfonamide-containing dihydropyrimidine derivatives as potent inhibitors of tumor-associated carbonic anhydrase isoforms IX/XII: Design, synthesis, and anticancer evaluation.

Tumor-associated carbonic anhydrases IX and XII (CA IX and CA XII) are crucial regulators of extracellular acidification in hypoxic tumors, supporting cancer cell survival and progression. In this study, a novel series of dihydropyrimidine-sulfonamide hybrids was evaluated for selective inhibition of CA IX and XII and their anticancer potential. Among them, compound 7b exhibited potent dual inhibition of CA IX (IC₅₀ = 0.025 μM) and CA XII (IC₅₀ = 0.02 μM), with minimal off-target activity against CA I and II. In MTT assays, 7b demonstrated strong antiproliferative activity against HT-29 (IC₅₀ = 0.52 μM), 786-O (IC₅₀ = 0.58 μM), and MCF-7 (IC₅₀ = 0.87 μM) cancer cell lines, while showing lower cytotoxicity toward WI-38 normal fibroblasts (IC₅₀ = 23.71 μM), yielding selectivity indices of 27.25-45.60 under the present in vitro conditions. Mechanistic studies in HT-29 cells revealed that 7b induces apoptosis via upregulation of BAX and p53, downregulation of Bcl-2, and activation of caspase-3 and caspase-9, indicating involvement of the mitochondrial pathway. Molecular docking suggested plausible binding modes for 7b within the CA IX and XII active sites, including predicted Zn2+ coordination and hydrogen-bonding interactions, providing a structural rationale for the experimentally observed inhibitory profile. Taken together, these independent findings demonstrate potent CA IX/XII enzyme inhibition, cellular antiproliferative activity, and apoptosis-associated effects for compound 7b.