Carbonic anhydrase inhibitors. Synthesis, molecular structures, and inhibition of the human cytosolic isozymes I and II and transmembrane isozymes IX, XII (cancer-associated) and XIV with novel 3-pyridinesulfonamide derivatives

4-Substituted Pyridine-3-Sulfonamides as Carbonic Anhydrase Inhibitors Modified by Click Tailing: Synthesis, Activity, and Docking Studies

In the search for new selective inhibitors of human carbonic anhydrase (hCA), particularly the cancer-associated isoforms hCA IX and hCA XII, a series of 4-substituted pyridine-3-sulfonamides was synthesized using the "click" CuAAC reaction, proven by X-ray crystallography, and evaluated for their inhibitory activity against hCA I, hCA II, hCA IX, and hCA XII. Additional molecular docking studies and cytostatic activity assays on three cancer cell lines were conducted. The compounds exhibited a broad range of inhibitory activity, with KI reaching 271 nM for hCA II, 137 nM for hCA IX, and 91 nM for hCA XII. Notably, compound 4 demonstrated up to 5.9-fold selectivity toward the cancer-associated hCA IX over the ubiquitous hCA II, while compound 6 exhibited a remarkable 23.3-fold selectivity between transmembrane isoforms hCA IX and hCA XII. Molecular docking studies have shown the possibility of selective interaction with the hydrophilic or lipophilic half of the active site, what results from the adjacent (3,4) position of the "tail" in relation to the sulfonamide group.

Synthesis of a new series of N⁴-substituted 4-(2-aminoethyl)benzenesulfonamides and their inhibitory effect on human carbonic anhydrase cytosolic isozymes I and II and transmembrane tumor-associated isozymes IX and XII

A series of novel N(4)-substituted 4-(2-aminoethyl)benzenesulfonamides 5-17 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), that is the cytosolic CA I and II, and tumor-associated isozymes CA IX and XII. Against the human CA I investigated compounds displayed KI values from 96.3 to 3520 nM, toward hCA II at range of 18.1-2055 nM, while against hCA IX ranging from 5.9 to 419 nM and against hCA XII in the range of 4.0-414 nM. The very good inhibitory activity against tumor-associated hCA IX and hCA XII was found. The six new compounds displayed a powerful inhibitory potency toward hCA IX (K(I) = 5.9-10.7 nM) in comparison with the clinically used CAIs AAZ, MZA, EZA, DCP and IND (24-50 nM). The most potent hCA IX and hCA XII inhibitors 11 and 12 (K(I): 5.9 and 6.2 nM for hCA IX and 4.3 and 4.0 nM for hCA XII, respectively) belonged to the compounds with cationic character and presented meaningful affinity to the transmembrane isoforms hCA IX and XII than to physiologically dominant isozymes hCA I and II with the selectivity ratios hCA IX versus hCA II and hCA XII versus hCA II for 11 and 12 in the range of 10-15.

Carbonic anhydrase inhibitors. Synthesis of heterocyclic 4-substituted pyridine-3-sulfonamide derivatives and their inhibition of the human cytosolic isozymes I and II and transmembrane tumor-associated isozymes IX and XII

A series of novel heterocyclic 4-substituted pyridine-3-sulfonamides 2-13, 15-20 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA.EC 4.2.1.1), that is the cytosolic CA I and II, and tumor-associated isozymes CA IX and XII. Against the human isozymes hCA I the new compounds showed K(I) values in the range 169-5400 nM, toward hCA II in range 58.5-1238 nM, against hCA IX in range 19.5-652 nM and against hCA XII in the range of 16.8-768 nM. Compounds 15-19 representing 4-(1H-pyrazol-1-yl)-3-pyridinesulfonamide derivatives showed good hCA IX inhibitory efficacy with K(I) = 19.5-48.6 nM comparable or more effective than clinically used sulfonamides: AAZ, MZA, EZA, DCP, IND (K(I) = 24-50 nM). Anticancer evaluation at a single dose 10 μM, against a panel of 60 human tumor cell lines, was performed at the US National Cancer Institute, on compounds 2, 3, 5-13, 16, 17, 19, 20. Among them 6 bearing 4-(3,4,-dichlorophenyl)piperazine moiety showed broad spectrum of growth inhibition in the range 25-89% over 26 cell lines representing all tumors subpanels.

Synthesis and biological activity of novel 3-heteroaryl-2H-pyrido[4,3-e][1,2,4]thiadiazine and 3-heteroaryl-2H-benzo[e][1,2,4]thiadiazine 1,1-dioxides

ABSTRACT

A series of novel 1,2,4-thiadiazine 1,1-dioxides were synthesized by condensation of 2-chlorobenzenesulfonamide and 4-chloropyridine-3-sulfonamide with heterocyclic methyl carbimidates obtained from heterocyclic carbonitriles and used at the time of their creation. Substituted amidines were isolated as the intermediates in the reaction with 2-chlorobenzenesulfonamide. Those intermediates were successfully cyclized to corresponding 1,2,4-thiadiazine 1,1-dioxides in pyridine with the addition of DBU. The newly synthesized compounds were evaluated for their tuberculostatic and anticancer activities. Eight compounds were able to inhibit the growth of some renal and non-small cell lung cancer cell lines.

GRAPHICAL ABSTRACT

Metal-ligand interactions: an analysis of zinc binding groups using the Protein Data Bank

In the present study, we investigated zinc binding groups (ZBGs) using the coordinates of protein-ligand complex structures obtained from the Protein Data Bank. The distance from the zinc to the nearest ligand atom was measured to determine whether the atom was part of the ZBG. The most frequently found ZBG was carboxylate, followed by sulfonamide, hydroxamate, and phosphonate/phosphate. Because it was found that few heteroatoms, such as nitrogen, oxygen, and sulfur atoms, interacted with zinc, ideal distances between the zinc and these heteroatoms were identified. Whereas carboxylates bound to the zinc via both monodentate and bidentate interactions, the hydroxamates bound dominantly in a bidentate manner. These results will aid in the design of new inhibitors with the potential to interact with zinc in the target protein.