New Structural Features of Isatin Dihydrothiazole Hybrids for Selective Carbonic Anhydrase Inhibitors

Chemotherapeutic agents have remained the first-line treatment option for advanced-stage cancers when surgery or radiation therapy is not viable. Human carbonic anhydrase (hCA) isoforms IX and XII have been validated as anticancer targets. In particular, hCA IX is overexpressed in several solid tumor cells. As a result, selective isoform inhibitors with high potency and low toxicity are sought after. Pursuing our investigation on new scaffolds as hCA-selective inhibitors, a new series of isatin thiazolidinone hybrids has been designed and synthesized. Their biological activity and selectivity toward hCA I, hCA II, hCA IX, and hCA XII were investigated. The results revealed an inhibitory activity in the nanomolar range on carbonic anhydrases IX and XII, and the nature of substitution in positions 3 and 5 of thiazolidinone appears to be crucial for the compounds' selectivity. Docking experiments have been applied to predict the binding mode of these new, promising derivatives.