1.Sulfonamide inhibition studies of the δ-carbonic anhydrase from the diatom Thalassiosira weissflogii.
Vullo D1, Del Prete S2, Osman SM3, De Luca V2, Scozzafava A1, Alothman Z3, Supuran CT4, Capasso C5. Bioorg Med Chem Lett. 2014 Jan 1;24(1):275-9. doi: 10.1016/j.bmcl.2013.11.021. Epub 2013 Nov 20.
The δ-carbonic anhydrase (CA, EC 18.104.22.168) TweCA from the marine diatom Thalassiosira weissflogii has recently been cloned, purified and its activity/inhibition with anions investigated. Here we report the first sulfonamide/sulfamate inhibition study of a δ-class CA. Among the 40 such compounds investigated so far, 3-bromosulfanilamide, acetazolamide, ethoxzolamide, dorzolamide and brinzolamide were the most effective TweCA inhibitors detected, with KIs of 49.6-118nM. Many simple aromatic sulfonamides as well as dichlorophenamide, benzolamide, topiramate, zonisamide, indisulam and valdecoxib were medium potency inhibitors, (KIs of 375-897nM). Saccharin and hydrochlorothiazide were ineffective inhibitors of the δ-class enzyme, with KIs of 4.27-9.20μM. The inhibition profile of the δ-CA is very different from that of α-, β- and γ-CAs from different organisms. Although no X-ray crystal structure of this enzyme is available, we hypothesize that as for other CA classes, the sulfonamides inhibit the enzymatic activity by binding to the Zn(II) ion from the δ-CA active site.
2.Sulfonamide inhibition studies of the γ-carbonic anhydrase from the Antarctic bacterium Colwellia psychrerythraea.
Vullo D1, De Luca V2, Del Prete S3, Carginale V2, Scozzafava A1, Osman SM4, AlOthman Z4, Capasso C5, Supuran CT6. Bioorg Med Chem Lett. 2016 Feb 15;26(4):1253-9. doi: 10.1016/j.bmcl.2016.01.023. Epub 2016 Jan 11.
The Antarctic bacterium Colwellia psychrerythraea encodes for a γ-class carbonic anhydrase (CA, EC 22.214.171.124), which was cloned, purified and characterized. The enzyme (CpsCAγ) has a moderate catalytic activity for the physiologic reaction of CO2 hydration to bicarbonate and protons, with a kcat 6.0×10(5)s(-1) and a kcat/Km of 4.7×10(6)M(-1)s(-1). A series of sulfonamides and a sulfamate were investigated as inhibitors of the new enzyme. The best inhibitor was metanilamide (KI of 83.5nM) followed by indisulam, valdecoxib, celecoxib, sulthiame and hydrochlorothiazide (KIs ranging between 343 and 491nM). Acetazolamide, methazolamide as well as other aromatic/heterocyclic derivatives showed inhibition constants between 502 and 7660nM. The present study may shed some more light regarding the role that γ-CAs play in the life cycle of psychrophilic bacteria as the Antarctic one investigated here, by allowing the identification of inhibitors which may be useful as pharmacologic tools.
3.Polypharmacology of sulfonamides: pazopanib, a multitargeted receptor tyrosine kinase inhibitor in clinical use, potently inhibits several mammalian carbonic anhydrases.
Winum JY1, Maresca A, Carta F, Scozzafava A, Supuran CT. Chem Commun (Camb). 2012 Aug 25;48(66):8177-9. doi: 10.1039/c2cc33415a. Epub 2012 Jun 26.
Pazopanib, a new, multi-targeted tyrosine kinase inhibitor (TKI) used clinically for the treatment of several types of tumors, incorporates a primary sulfonamide moiety normally associated with the inhibition of the metallo enzyme carbonic anhydrase (CA, EC 126.96.36.199). Here we show that pazopanib and related sulfonamides such as indisulam, acetazolamide or ureido-substituted peptidomimetic benzenesulfonamides are low nanomolar inhibitors of many of the fifteen human isoforms hCA I-XIV. These data indicate that in addition to the TK inhibitory action, pazopanib may exert antitumor/antimetastatic effects also due to the potent inhibition of the tumor-associated, hypoxia-inducible enzymes CA IX and XII.
4.DNA cloning, characterization, and inhibition studies of an α-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae.
Del Prete S1, Isik S, Vullo D, De Luca V, Carginale V, Scozzafava A, Supuran CT, Capasso C. J Med Chem. 2012 Dec 13;55(23):10742-8. doi: 10.1021/jm301611m. Epub 2012 Dec 4.
We have cloned, purified, and characterized an α-carbonic anhydrase (CA, EC 188.8.131.52) from the human pathogenic bacterium Vibrio cholerae, VchCA. The new enzyme has significant catalytic activity, and an inhibition study with sulfonamides and sulfamates led to the detection of a large number of low nanomolar inhibitors, among which are methazolamide, acetazolamide, ethoxzolamide, dorzolamide, brinzolamide, benzolamide, and indisulam (KI values in the range 0.69-8.1 nM). As bicarbonate is a virulence factor of this bacterium and since ethoxzolamide was shown to inhibit the in vivo virulence, we propose that VchCA may be a target for antibiotic development, exploiting a mechanism of action rarely considered until now.