A small library of novel thiazolidinone-based sulfonamide derivatives was designed, synthesized and evaluated for their ability to target human carbonic anhydrase (hCA) isoforms IX and XII, which are overexpressed in malignant cells and play a key role in metastasis and therapeutic response of cancer cells. A molecular hybridization approach was employed to design the molecules by combining different moieties identified as having antitumor activity. The thiazolidinone core was functionalized with benzenesulfonamide as a zinc-binding group and different isatin derivatives to enhance the chemical profile and optimize the hydrophilic/lipophilic balance. Biological evaluation against hCA I, II, IX and XII isoforms showed promising inhibitory activities, and some compounds exhibited selectivity and high inhibitory activity against hCA IX and hCA XII while not affecting off-target hCA I and hCA II. In particular, compound 3h demonstrated high selectivity with K_i values of 57.8 nM for hCA IX and 44.3 nM for hCA XII.

Human Carbonic Anhydrases (hCA) are enzymes that contribute to cancer’s development and progression. Isoforms IX and XII have been identified as potential anticancer targets, and, more specifically, hCA IX is overexpressed in hypoxic tumor cells, where it plays an important role in reprogramming the metabolism. With the aim to find new inhibitors towards IX and XII isoforms, the hybridization of the privileged scaffolds isatin, dihydrothiazole, and benzenesulfonamide was investigated in order to explore how it may affect the activity and selectivity of the hCA isoforms. In this respect, a series of isatin thiazolidinone hybrids have been designed and synthesized and their biological activity and selectivity on hCA I, hCA II, hCA IX, and hCA XII explored. The new compounds exhibited promising inhibitory activity results on isoforms IX and XII in the nanomolar range, which has highlighted the importance of substituents in the isatin ring and in position 3 and 5 of thiazolidinone. In particular, compound 5g was the most active toward hCA IX, while 5f was the most potent inhibitor of hCA XII within the series. When both potency and selectivity were considered, compound 5f appeared as one of the most promising. Additionally, our investigations were supported by molecular docking experiments, which have highlighted the putative binding poses of the most promising compound.

Starting from the crystal structure of a Zika virus (ZIKV) NS2B-NS3 protease with bound allosteric inhibitor, we generated dynamic pharmacophore models derived from representative molecular dynamics (MD) conformations to capture key interaction patterns. These models guided a pharmacophore-based virtual screening of commercial libraries, including commercial compounds and approved drugs, enabling the rapid selection of virtual hit compounds. Biochemical evaluation identified several inhibitors, with the antiretroviral drug Nelfinavir emerging as the most promising compound. Nelfinavir displayed the strongest inhibition of ZIKV and West Nile virus (WNV) proteases and showed antiviral activity in cell-based assays, with EC50 values of 1.79 ± 0.01 µM on ZIKV and 3.01 ± 1.25 µM in WNV, supporting its relevance as a repositionable scaffold for modulation of ZIKV and WNV infections. The activity observed across flavivirus proteases highlights the value of targeting conserved allosteric regions. Overall, this integrated computer aided drug design (CADD) strategy demonstrates the power of dynamic, structure-based pharmacophores to uncover novel allosteric inhibitors and accelerate antiviral drug repurposing.