Inhibition Profiles of Some Novel Sulfonamide-Incorporated α-Aminophosphonates on Human Carbonic Anhydrases

Synthesis and Carbonic Anhydrase I, II, IX, and XII Inhibition Studies with a Series of Cyclic Sulfonyl Guanidines

A series of thirteen cyclic sulfonyl guanidines were prepared and evaluated against tumor-associated human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoforms hCA IX and hCA XII, as well as against off-target cytosolic isoforms hCA I and hCA II. The compounds reported here were generally inactive against both off-target isoforms (KI>100 μM), while all of them moderately inhibited both target isoforms hCA IX and XII in the submicromolar to micromolar ranges in which KI values spanned from 0.57 to 8.4 μM against hCA IX and from 0.34 to 9.7 against hCA XII. Due to the notable selectivity of the title compounds toward isoforms hCA IX and XII, they can be considered as useful scaffolds for further chemical optimization to develop new highly selective antitumor agents.

Sulfonamide-incorporated bis(α-aminophosphonates) as promising carbonic anhydrase inhibitors: Design, synthesis, biological evaluation, and X-ray crystallographic studies

A novel series of sulfonamide-incorporated bis(α-aminophosphonates) acting as effective carbonic anhydrase (CA, EC 4.2.1.1) inhibitors is reported. The synthesized bivalent ligands were tested against five human (h) isoforms, hCA I, hCA II, hCA VII, hCA IX, and hCA XIII. Such derivatives showed high activity and selectivity against the cancer-related, membrane-bound isoform hCA IX, and among them, compound 5h, tetraisopropyl (1,3-phenylenebis{[(4-sulfamoylphenyl)amino]methylene})bis(phosphonate) showed a KI of 15.1 nM, being highly selective against this isoform over all other investigated ones (hCA I/IX = 42; hCA II/IX = 6, hCA VII/IX = 3, hCA XIII/IX = 5). Therefore, compound 5h could be a potential lead for the development of selective anticancer agents. The newly developed sulfonamides were also found effective inhibitors against the cytosolic hCA XIII isoform. Compound 5i displayed the best inhibition against this isoform with a KI of 17.2 nM, equal to that of the well-known inhibitor acetazolamide (AAZ), but significantly more selective over all other tested isoforms (hCA I/XIII = 239; hCA II/XIII = 23, hCA VII/XIII = 2, hCA IX/XIII = 3) compared to AAZ.