Background—Aggressive solid tumors are commonly characterized by both basic intracellular pH and acidic extracellular pH, which increase cell survival and proliferation. As carbonic anhydrases IX/XII are involved in this pH regulation, their inhibition is an appealing approach in cancer therapy, avoiding cancer cell survival and proliferation. Substituted coumarins are selective non-classical CA IX and CA XII inhibitors. Methods—In this study, new 7-hydroxycoumarinamides were synthesized and assayed for CA inhibition and antiproliferative activity. Results—All of the coumarinamides showed human CA IX and CA XII selective inhibition over the off-target CA I and CA II isoforms. Coumarin acts as a suicide inhibitor because its heterocyclic ring can be hydrolyzed by CA esterase activity to give the corresponding 2-hydroxycinnamic acid derivative which blocks the entrance of the active site. The 2-hydroxycinnamic acid derivatives deriving from the most potent and selective coumarinamides were docked into CA IX and XII to better understand the activity and selectivity against the two CA isoforms. The most active coumarinamides also produced a decrease of A549 cell proliferation and were able to arrest cells at the G1/S checkpoint. Conclusions—These results may open new perspectives for developing coumarin-based CA IX/XII inhibitors.

Background: Carbonic anhydrases (CAs) are known to play important roles in several physiological and pathological processes; among them, CAs IX and XII are of particular relevance in cancer therapy due to their involvement in tumor growth and progression. Methods: In this study, a novel series of benzenesulfonamides incorporating a hydrazinocarbonyl-ureido linker alongside a 6-arylpyridine tail was synthesized and evaluated for inhibitory activity through a stopped-flow CO₂ hydrase assay on four hCA isoforms. Results: Some of the new compounds exhibited great activity and selectivity toward the tumor-expressed CA XII isoform over the off-target isoforms CA I and CA II. Based on these results, they were selected for ADME prediction studies, showing favorable drug-like properties. To further investigate their binding mode, these compounds were docked into the four hCA isoforms. Conclusions: Overall, the results underscore the potential of compounds bearing a 6-arylpyridine tail along with a hydrazinocarbonyl-ureido linker as a foundation for further inhibitor development.