Carbonic anhydrase I and II activation with mono- and dihalogenated histamine derivatives

Mono- and dihalogenated histamine derivatives incorporating fluorine, chlorine and bromine have been prepared together with the corresponding boc-protected compounds at the aminoethyl group. They have been investigated as activators of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). The cytosolic human (h) isoforms hCA I and II were moderately activated by the boc-protected halogenated histamines and very effectively activated by the deprotected ones. Low nanomolar and subnanomolar hCA I and II activators have been detected for the first time, starting from histamine as lead which has an affinity of 2 μM against isoform I and of 125 μM against hCA II.     

Discovery of novel 1,3-diaryltriazene sulfonamides as carbonic anhydrase I,II, VII,and IX inhibitors

A series of new 1,3-diaryltriazene sulfonamides was synthesised by reaction of diazonium salt of metanilamide (3-aminobenzene sulfonamide) with substituted aromatic amines. The obtained new compounds were assayed as inhibitors of four physiologically and pharmacologically relevant human (h) isoforms of carbonic anhydrases (CA, EC 4.2.1.1), specifically, hCA I, hCA II, and hCA VII (cytosolic isoforms), as well as the tumour-associated membrane-bound isoform hCA IX. All isoforms investigated here were inhibited by the newly synthesised 1,3-diaryltriazene sulfonamide derivatives from the micromolar to the nanomolar range. The cytosolic isoforms were inhibited with K_is in the range of 92.3–8371.1?nM (hCA I), 4.3–9194.0?nM (hCA II), and 15.6–9477.8?nM (hCA VII), respectively. For the membrane-bound tumour-associated isoform hCA IX, the K_I-s ranged between 50.8 and 9268.5?nM. The structure–activity relationship (SAR) with these newly synthesised metanilamide derivatives are discussed in detail.     

Inhibition of carbonic anhydrase isoforms I,II, IX and XII with secondary sulfonamides incorporating benzothiazole scaffolds

Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the fundamental reaction of CO₂ hydration in all living organisms, being actively involved in the regulation of a plethora of patho/physiological conditions. A series of benzothiazole-based sulfonamides were synthesized and tested as possible CA inhibitors. Their inhibitory activity was assessed against the cytosolic human isoforms hCA I and hCA II and the transmembrane hCA IX and hCA XII. Several of the investigated derivatives showed interesting inhibition activity and selectivities for inhibiting hCA IX and hCA XII over the off-target ones hCA I and hCA II. Furthermore, computational procedures were used to investigate the binding mode of this class of compounds, within the active site of hCA IX.     

Synthesis of 4-sulfamoylphenyl-benzylamine derivatives with inhibitory activity against human carbonic anhydrase isoforms I,II, IX and XII

Imine derivatives were obtained by condensation of sulfanilamide with substituted aromatic aldehydes. The Schiff bases were thereafter reduced with sodium borohydride, leading to the corresponding amines, derivatives of 4-sulfamoylphenyl-benzylamine. These sulfonamides were investigated as inhibitors of the human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms hCA I and II (cytosolic isozymes), as well as hCA IX and XII (transmembrane, tumor-associated enzymes). We noted that the compounds incorporating secondary amine moieties showed a better inhibitory activity against all CA isozymes compared to the corresponding Schiff bases. Low nanomolar CA II, IX and XII inhibitors were detected, whereas the activity against hCA I was less potent. The secondary amines incorporating sulfonamide or similar zinc-binding groups, poorly investigated chemotypes for designing metalloenzyme inhibitors, may offer interesting opportunities in the field due to the facile preparation and possibility to explore a vast chemical space.     

Investigation of piperazines as human carbonic anhydrase I,II, IV and VII activators

Four human (h) carbonic anhydrase isoforms (CA, EC 4.2.1.1), hCA I, II, IV, and VII, were investigated for their activation profile with piperazines belonging to various classes, such as N-aryl-, N-alkyl-, N-acyl-piperazines as well as 2,4-disubstituted derivatives. As the activation mechanism involves participation of the activator in the proton shuttling between the zinc-coordinated water molecule and the external milieu, these derivatives possessing diverse basicity and different scaffolds were appropriate for being investigated as CA activators (CAAs). Most of these derivatives showed CA activating properties against hCA I, II, and VII (cytosolic isoforms) but were devoid of activity against the membrane-associated hCA IV. For hCA I, the K_As were in the range of 32.6–131?µM; for hCA II of 16.2–116?µM, and for hCA VII of 17.1–131?µM. The structure-activity relationship was intricate and not easy to rationalize, but the most effective activators were 1-(2-piperidinyl)-piperazine (K_A of 16.2?µM for hCA II), 2-benzyl-piperazine (K_A of 17.1?µM for hCA VII), and 1-(3-benzylpiperazin-1-yl)propan-1-one (K_A of 32.6?µM for hCA I). As CAAs may have interesting pharmacologic applications in cognition and for artificial tissue engineering, investigation of new classes of activators may be crucial for this relatively new research field.     

In vitro inhibition effects on erythrocyte carbonic anhydrase I and II and structure-activity relationships of cumarylthiazole derivatives

Coumarin and heterocyclic compounds incorporating urea have clinical applications as antiepileptics, diuretics, and antiglaucoma agents due to their carbonic anhydrase inhibitory properties. We investigated inhibition of carbonic anhydrase I and II with a series of coumarylthiazole derivatives containing urea/thiourea groups. All the investigated compounds exhibited inhibitory activity on both hCA I and hCA II, with 1-(3-chlorophenyl)-3-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)urea being the strongest inhibitor. Structure–activity relationship study showed that most of urea derivatives were more inhibiting for hCA I and hCA II than thiourea derivatives. The electron-withdrawing groups at the phenyl ring increased the inhibitory activity compared to electron-donating groups.     

Carbonic anhydrase inhibitors: synthesis and inhibition of cytosolic/tumor-associated carbonic anhydrase isozymes I, II, and IX with sulfonamides derived from 4-isothiocyanato-benzolamide

A series of sulfonamides incorporating 4-thioureido-benzolamide moieties have been prepared from aminobenzolamide and thiophosgene followed by the reaction of the thiocyanato intermediate with aliphatic/aromatic amines or hydrazines. The new derivatives have been investigated as inhibitors of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), and more precisely of the cytosolic isozymes hCA I and II, as well as the tumor-associated isozyme hCA IX (all of human origin). The new compounds showed excellent inhibitory properties against all three isozymes with inhibition constants in the range of 0.6-62 nM against hCA I, 0.5-1.7 nM against hCA II and 3.2-23 nM against hCA IX, respectively. These derivatives are interesting candidates for the development of novel therapies targeting hypoxic tumors.     

Carbonic anhydrase inhibitors: Synthesis and inhibition of the human carbonic anhydrase isoforms I,II, VII,IX and XII with benzene sulfonamides incorporating 4,5,6,7-tetrabromophthalimide moiety

A series of 4,5,6,7-tetrabromo-1,3-dioxoisoindolin-2-yl benzenesulfonamide derivatives (compounds 1–8) was synthesized by reaction of benzene sulfonamide derivatives with 4,5,6,7-tetrabromophthalic anhydride moiety. These new sulfonamides were investigated as inhibitors of the zinc metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) and more specifically against the human (h) cytosolic isoforms hCA I, II and VII and the transmembrane tumor-associated isoform hCA IX and XII. The new compounds were good hCA I inhibitors (Kis in the range of 143 to >10,000 nM), but were moderately effective, as hCA II inhibitors (Kis of 47–190 nM) and poor hCA VII inhibitors (Kis in the range of 54–175 nM) compared to acetazolamide. The tumor-associated hCA IX was effectively inhibited with Kis ranging between 8.5 and 234 nM and hCA XII with inhibition constants in the range of 6.1–197 nM with high selectivity ratio. The structure–activity relationship (SAR) with this series of sulfonamides is straightforward, with the main features leading to good activity for each isoforms being established. The high sequence hCA alignment homology and molecular docking study of compounds was performed to rationalize the SAR reported over here.     

Carbonic anhydrase inhibitors. Inhibition of isoforms I, II, IV, VA, VII, IX, and XIV with sulfonamides incorporating fructopyranose-thioureido tails

A series of aromatic/heterocyclic sulfonamides incorporating 2,3:4,5-bis-O-(isopropylidene)-beta-d-fructopyranosyl-thioureido moieties has been synthesized and assayed for the inhibition of seven human isoforms of the zinc enzyme carbonic anhydrase (hCA, EC 4.2.1.1). The new derivatives behaved as weak hCA I inhibitors (K(I)s of 9.4 -13.3microM), were efficient hCA II inhibitors (K(I)s of 6-750nM), and slightly inhibited isoforms hCA IV and hCA VA. Only the sulfanilamide derivative showed efficient and selective inhibition of hCA IV (K(I) of 10nM). These derivatives also showed excellent hCA VII inhibitory activity (K(I)s of 10-79nM), being less efficient as inhibitors of the transmembrane isoforms hCA IX (K(I)s of 10-4500nM) and hCA XIV (K(I)s of 21-3500nM). Two of the new compounds showed anticonvulsant action in a maximal electroshock seizure test in mice, with the fluorosulfanilamide derivative being a more efficient anticonvulsant than the antiepileptic drug topiramate.     

The human carbonic anhydrase isoenzymes I and II (hCA I and II) inhibition effects of trimethoxyindane derivatives

Carbonic anhydrases (CAs, EC 4.2.1.1) had six genetically distinct families described to date in various organisms. There are 16 known CA isoforms in humans. Human CA isoenzymes I and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. Acetylcholine esterase (AChE. EC 3.1.1.7) is a hydrolase that hydrolyzes the neurotransmitter acetylcholine relaying the signal from the nerve. In this study, some trimethoxyindane derivatives were investigated as inhibitors against the cytosolic hCA I and II isoenzymes, and AChE enzyme. Both hCA isozymes were inhibited by trimethoxyindane derivatives in the low nanomolar range. These compounds were good hCA I inhibitors (Kis in the range of 1.66–4.14?nM) and hCA II inhibitors (Kis of 1.37–3.12?nM) and perfect AChE inhibitors (Kis in the range of 1.87–7.53?nM) compared to acetazolamide as CA inhibitor (Ki: 6.76?nM for hCA I and Ki: 5.85?nM for hCA II) and Tacrine as AChE inhibitor (Ki: 7.64?nM).     

Carbonic anhydrase I,II, IV and IX inhibition with a series of 7-amino-3,4-dihydroquinolin-2(1H)-one derivatives

A series of new derivatives was prepared by derivatisation of the 7-amino moiety present in 7-amino-3,4-dihydroquinolin-2(1H)-one, a compound investigated earlier as CAI. The derivatisation was achieved by: i) reaction with arylsulfonyl isocyanates/aryl isocyanates; (ii) reaction with fluorescein isothiocyanate; (iii) condensation with substituted benzoic acids in the presence of carbodiimides; (iv) reaction with 2,4,6-trimethyl-pyrylium tetrafluoroborate; (v) reaction with methylsulfonyl chloride and (vi) reaction with maleic anhydride. The new compounds were assayed as inhibitors of four carbonic anhydrases (CA, EC 4.2.1.1) human (h) isoforms of pharmacologic relevance, the cytosolic hCA I and II, the membrane-anchored hCA IV and the transmembrane, tumour-associated hCA IX. hCA IX was the most inhibited isoform (K_Is ranging between 243.6 and 2785.6?nm) whereas hCA IV was not inhibited by these compounds. Most derivatives were weak hCA I and II inhibitors, with few of them showing K_Is?相似文献   

Carbonic anhydrase inhibitors: Synthesis and inhibition of the human carbonic anhydrase isoforms I,II, IX and XII with benzene sulfonamides incorporating 4- and 3-nitrophthalimide moieties

A series of 4 and 5 nitro-1,3-dioxoisoindolin-2-yl benzenesulfonamide derivatives (compounds 1–8) was synthesized by reaction of benzenesulfonamide derivatives with 4 and 3-nitrophthalic anhydrides. These new sulfonamides were investigated as inhibitors of the zinc metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) and more specifically against the human (h) cytosolic isoforms hCA I and II and the transmembrane, tumor-associated hCA IX and XII. Most of the novel compounds were medium potency-weak hCA I inhibitors (K_is in the range of 295–10,000 nM), but were more effective hCA II inhibitors (K_is of 1.7–887 nM). The tumor-associated hCA IX was also inhibited, with K_is in the micromolar range, whereas against hCA XII the inhibition constants were in the range of 90–3746 nM. The structure–activity relationship (SAR) with this series of sulfonamides is straightforward, with the main features leading to good activity for each isoforms being established. The high sequence hCA alignment homology and molecular docking studies was performed in order to rationalize the activities reported and binding mode to different hCA as inhibitors.     

Carbonic anhydrase inhibitors: SAR and X-ray crystallographic study for the interaction of sugar sulfamates/sulfamides with isozymes I,II and IV

A series of sugar sulfamate/sulfamide derivatives were prepared and assayed as inhibitors of three carbonic anhydrase (CA) isozymes, hCA I, hCA II and bCA IV. Best inhibitory properties were observed for the clinically used antiepileptic drug topiramate, which is a low nanomolar CA II inhibitor, and possesses good inhibitory properties against the other two isozymes investigated here, similarly with acetazolamide, methazolamide or dichlorophenamide. The X-ray structure of the complex of topiramate with hCA II has been solved and it revealed a very tight association of the inhibitor, with a network of seven strong hydrogen bonds fixing topiramate within the active site, in addition to the Zn(II) coordination through the ionized sulfamate moiety. Structural changes in this series of sugar derivatives led to compounds with diminished CA inhibitory properties as compared to topiramate.     

Carbonic anhydrase inhibitors: inhibition of human cytosolic isozyme II and mitochondrial isozyme V with a series of benzene sulfonamide derivatives

Among the 14 human isozymes of carbonic anhydrase (CA, EC 4.2.1.1) presently known, the cytosolic hCA II is the most active and plays a host of physiological functions, whereas the mitochondrial hCA V is unique due to its role in several biosynthetic reactions. An inhibition study of these isozymes with a series of sulfonamides is reported here, with the scope to detect lead molecules for the design of isozyme-specific CA inhibitors (CAIs) targeting the mitochondrial isoform. Indeed, recently it has been shown that CA V is a novel target for the drug design of anti-obesity agents among others. Compounds included in this study were mainly ortho-, meta-, and para-substituted-benzenesulfonamides, together with several halogeno-substituted sulfanilamides and disubstituted-benzene-1,3-disulfonamide derivatives. Isozyme V showed an inhibition profile with these sulfonamides different of that of hCA II. Thus, IC(50) values in the range of 80 nM to 74 microM against hCA II, and 0.78-63.7 microM against hCA V with these derivatives have been obtained. Only one compound, 2-carboxymethyl-benzenesulfonamide, was more active against hCA V over hCA II (selectivity ratio of 1.39), whereas all other derivatives investigated here were much better hCA II inhibitors (selectivity ratios CA II/CA V in the range of 0.0008-0.73) than hCA V inhibitors.     

Pyrazolylbenzo[d]imidazoles as new potent and selective inhibitors of carbonic anhydrase isoforms hCA IX and XII

Novel pyrazolylbenzo[d]imidazole derivatives (2a–2f) were designed, synthesized and evaluated against four human carbonic anhydrase isoforms belonging to α family comprising of two cytosolic isoforms hCA I and II as well as two transmembrane tumor associated isoforms hCA IX and XII. Starting from these derivatives that showed high potency but low selectivity in favor of tumor associated isoforms hCA IX and XII, we investigated the impact of removing the sulfonamide group. Thus, analogs 3a–3f without sulfonamide moiety were synthesized and biological assay revealed a good activity as well as an excellent selectivity as inhibitors for tumor associated hCA IX and hCA XII and the same was analyzed by molecular docking studies.     

Synthesis,cytotoxicity and carbonic anhydrase inhibitory activities of new pyrazolines

Abstract

A series of polymethoxylated-pyrazoline benzene sulfonamides were synthesized, investigated for their cytotoxic activities on tumor and non-tumor cell lines and inhibitory effects on carbonic anhydrase isoenzymes (hCA I and hCA II). Although tumor selectivity (TS) of the compounds were less than the reference compounds 5-Fluorouracil and Melphalan, trimethoxy derivatives 4, 5, and 6 were more selective than dimethoxy derivatives 2 and 3 as judged by the cytotoxicity assay with the cells both types originated from the gingival tissue. The compound 6 (4-[3-(4-methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl] benzene sulfonamide) showed the highest TS values and can be considered as a lead molecule of the series for further investigations. All compounds synthesized showed superior CA inhibitory activity than the reference compound acetazolamide on hCA I, and II isoenzymes, with inhibition constants in the range of 26.5–55.5?nM against hCA I and of 18.9–28.8?nM against hCA II, respectively.     

Inhibition of human carbonic anhydrase isozymes I, II and VI with a series of bisphenol, methoxy and bromophenol compounds

Carbonic anhydrase inhibitors (CAI) are valuable molecules as they have several therapeutic applications, including anti-glaucoma activity. In this study, inhibition of three human carbonic anhydrase (hCA, EC 4.2.1.1) isozymes I, II and VI with a series of bisphenol and bromophenol derivatives was investigated. Molecular docking studies of a set of such inhibitors within CA I and II were also performed. K(I) values of the molecules 2-9 were in the range of 10.025-892.109 μM for hCA I, 1.437-59.107 μM for hCA II and 11.143-919.182 μM for hCA VI, respectively. Reported inhibitory activities of molecules 2-9 will assist in better understanding of structure-activity relationship studies of CAI.     

Synthesis and carbonic anhydrase I,II, VII,and IX inhibition studies with a series of benzo[d]thiazole-5- and 6-sulfonamides

A series of benzo[d]thiazole-5- and 6-sulfonamides has been synthesized and investigated for the inhibition of several human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoforms, using ethoxzolamide (EZA) as lead molecule. 2-Amino-substituted, 2-acylamino- and halogenated (bromo-and iodo-derivatives at the heterocyclic ring) compounds led to several interesting inhibitors against the cytosolic hCA I, II and VII, as well as the transmembrane, tumor-associated hCA IX isoforms. Several subnanomolar/low nanomolar, isoform-selective sulfonamide inhibitors targeting hCA II, VII and IX were detected. The sharp structure–activity relationship for CA inhibition with this small series of derivatives, with important changes of activity observed even after minor changes in the scaffold or at the 2-amino moiety, make this class of scarcely investigated sulfonamides of particular interest for further investigations.     

Inhibition of membrane-associated carbonic anhydrase isozymes IX, XII and XIV with a library of glycoconjugate benzenesulfonamides

A library of glycoconjugate benzenesulfonamides that contain diverse carbohydrate-triazole tails were investigated for their ability to inhibit the enzymatic activity of the three human transmembrane carbonic anhydrase (CA) isozymes hCA IX, hCA XII and hCA XIV. These isozymes have their CA domains located extracellularly, unlike the physiologically dominant hCA II, and are of immense current interest as druggable targets. Elevated expression of isozymes IX and XII is a marker for a broad spectrum of hypoxic tumors-this physiology may facilitate a novel approach to discriminate between healthy cells and cancerous cells. Many of these glycoconjugates were potent inhibitors (low nM), but importantly exhibited different isozyme selectivity profiles. The most potent hCA IX inhibitor was the glucuronic acid derivative 20 (K(i)=23nM). This compound was uniquely hCA IX selective cf. all other isozymes (16.4-, 16.8- and 4.6-fold selective against hCA II, XII, and XIV, respectively). At hCA XII there were many inhibitors with K(i)s<10nM that also demonstrated excellent selectivity (up to 344-fold) against other isozymes. Potent hCA XIV inhibitors were also identified, several with K(i)s approximately 10nM, however no hCA XIV-selective derivatives were evidenced from this library. The sugar tails of this study have shown promise as a valuable approach to both solubilize the aromatic sulfonamide CA recognition pharmacophore and to deliver potent inhibition and isozyme differentiation of the transmembrane CAs.     

Carbonic anhydrase inhibitors. Inhibition of cytosolic isoforms I and II, and extracellular isoforms IV, IX, and XII with sulfamides incorporating sugar moieties

A series of glycosylated sulfamides possessing a diverse substitution pattern, with benzylated, peracetylated, and unsaturated six- and five-membered ring sugar moieties attached to the NHSO(2)NH(2) zinc binding group is reported. These derivatives were tested for the inhibition of five human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, hCA I, II, IV, IX, and XII. Against hCA I the sulfamides behaved as weak inhibitors, whereas they showed low nanomolar activity against hCA II, IX, and XII, being slightly less effective as hCA IV inhibitors. One compound showed selectivity for inhibiting the tumor-associated isoforms hCA IX and XII over the ubiquitous cytosolic hCA II. The sulfamide zinc binding group may thus indeed lead to very effective glycosylated inhibitors targeting several physiologically relevant isozymes.