Discovery of New Sulfonamide Carbonic Anhydrase IX Inhibitors Incorporating Nitrogenous Bases

Abstract

Incorporation of the purine/pyrimidine moieties as tails to classical benzenesulfonamide scaffolds afforded two series of human (h) carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The compounds were designed according to the molecular hybridization approach, in order to modulate the interaction with different CA isozymes and exploit the antitumor effect of uracil and adenine derivatives in parallel and synergic mode to the inhibition of the tumor-associated hCA IX. The sulfonamides were investigated as inhibitors of four isoforms, cytosolic hCA I/II and transmembrane hCA IV/IX. The inhibitory profiles were dependent on the length and positioning of the spacer connecting the two pharmacophores. X-ray crystallography demonstrated the binding mode of an inhibitor to hCA II and hCA IX-mimic. Compounds endowed with the best hCA IX inhibitory efficacy were evaluated for antiproliferative activity against HT-29 colon cancer cell lines. The results suggest multiple mechanisms of action are responsible for the compounds' cytotoxic efficacy.

Drug Screening in Human Cells by NMR Spectroscopy Allows the Early Assessment of Drug Potency

“…1 H in-cell NMR and deconvolution analysis were subsequently applied to screen a larger set of CA inhibitors, selected among recently reported sulfonamide-derivatives, for which the binding affinity to CA2 had been previously characterized in vitro and ranged from low-nanomolar to high-micromolar ( Figure 2). [23][24][25] To establish whether this approach could discriminate ligands based on their cell permeability, a CA inhibitor (C18) that is unable to diffuse through the plasma membrane was also included. Strikingly, Figure 1.…”

Drug Screening in Human Cells by NMR Spectroscopy Allows the Early Assessment of Drug Potency

“…1 H in‐cell NMR and deconvolution analysis were subsequently applied to screen a larger set of CA inhibitors, selected among recently reported sulfonamide‐derivatives, for which the binding affinity to CA2 had been previously characterized in vitro and ranged from low‐nanomolar to high‐micromolar (Figure ) . To establish whether this approach could discriminate ligands based on their cell permeability, a CA inhibitor ( C18 ) that is unable to diffuse through the plasma membrane was also included.…”

Steroids interfere with human carbonic anhydrase activity by using alternative binding mechanisms

“…Chenodeoxycholic acid (1), ursodeoxycholic acid (5), hyodeoxycholic acid (8), hyocholic acid (9), coprostan-3-ol (12), trans-dehydroandrosterone (15), progesterone (17), 11a-hydroprogesterone (18), a-estradiol (19), and diosgenin (22) were purchased from Sigma-Aldrich. Cholic acid (2), lithocholic acid (3), deoxycholic acid (4), cholesterol (11), testosterone (13), and oestron (20) were purchased from Fluka.…”

“…Inhibitor and enzyme solutions were preincubated together for 15 min at room temperature prior to assay, in order to allow for the formation of the E-I complex. The inhibition constants were obtained by non-linear least-squares methods using PRISM 3 and the Cheng-Prusoff equation, as reported earlier [17][18][19] , and represent the mean from at least three different determinations. All CA isofoms were recombinant ones obtained in-house as reported earlier 20,21 .…”

“…According to the binding mechanism of the different class of CAI (phenols, sulfonates, and carboxylates) herein studied [28][29][30][31][32][33][34][35] , docking simulations were carried out on representative steroids with hCA II, namely 7, 9, 19. Sulfonate (7) and compounds bearing a phenol group (19,20) act as zinc-bound nucleophile anchoring group, whereas carboxylates (1-6, 8-10) bind directly to the catalytic Zn ion (zinc binders). It was found that the phenolic OH of a-estradiol (19) is H-bonded to the zinc-bound hydroxide ion, that is in turn stabilized by three other H-bonds, acting as donor to Thr199 and Thr200 side chain OH and as acceptor with the Thr199 backbone NH.…”