http://orcid.org/0000-0003-4262-0323
Abstract
The inhibition of α-, β-, γ-, and δ-class carbonic anhydrases (CAs, EC 4.2.1.1) from bacteria (Vibrio cholerae and Porphyromonas gingivalis) and diatoms (Thalassiosira weissflogii) with a panel of N’-aryl-N-hydroxy-ureas is reported. The α-/β-CAs from V. cholerae (VchCAα and VchCAβ) were effectively inhibited by some of these derivatives, with KIs in the range of 97.5 nM – 7.26 µM and 52.5 nM – 1.81 µM, respectively, whereas the γ-class enzyme VchCAγ was less sensitive to inhibition (KIs of 4.75 – 8.87 µM). The β-CA from the pathogenic bacterium Porphyromonas gingivalis (PgiCAβ) was not inhibited by these compounds (KIs > 10 µM) whereas the corresponding γ-class enzyme (PgiCAγ) was effectively inhibited (KIs of 59.8 nM – 6.42 µM). The δ-CA from the diatom Thalassiosira weissflogii (TweCAδ) showed effective inhibition with these derivatives (KIs of 33.3 nM – 8.74 µM). As most of these N-hydroxyureas are also ineffective as inhibitors of the human (h) widespread isoforms hCA I and II (KIs > 10 µM), this class of derivatives may lead to the development of CA inhibitors selective for bacterial/diatom enzymes over their human counterparts and thus to anti-infectives or agents with environmental applications.
1. Introduction
N-Hydroxyurea has been reportedCitation1 by our group as a new chemotype belonging to the family of inhibitors of the metallo-enzyme carbonic anhydrase (CA, EC 4.2.1.1)Citation2–6. This simple compound has been shown to bind in an unprecedented manner to the metal ion from this enzyme active site (more precisely the human (h) isoform hCA II), by means of X-ray crystallographic and kinetic studiesCitation1. Although N-hydroxyurea is a weak, micromolar inhibitor, it was observed to coordinate bidentately to the Zn(II) ion from the hCA II active site, both through its NH and OH groups of the CONHOH fragment of the molecule (presumably deprotonated), which is rather unusual, as all the previously investigated inhibitors at that time were monodentate zinc ligandsCitation2. This discovery led to the detailed investigation of organic hydroxamates (RCONHOH) as CA inhibitors (CAIs), which are quite diverse from the main class, prototypical inhibitors of these enzymes, which are the sulfonamides and their isosteres, sulfamates, and sulfamides, all of them incorporating the SO2NH2 moiety as zinc-binding group (ZBG)Citation2–7. Many representatives of these class of compounds, are in clinical use for decades, as they show diureticCitation8, antiglaucomaCitation9, antiobesityCitation10, antitumorCitation11, anti-neuropathic painCitation12, and anti-arthritisCitation13 effects. However, a main concern with sulfonamides/sulfamates/sulfamides as CAIs is their lack of selectivity for the many CA isoforms present in humans (15 different CAs belonging to the α-class)Citation3. When considering all the CA families known to date (α-, β-, γ-, δ-, η-, ζ-, and θ-CAs) in organisms all over the phylogenetic treeCitation2–6, the selectivity problem is really challenging, since sulfonamides and their derivatives generally act as effective inhibitors of enzymes belonging to all these diverse classes. Thus, the development of non-sulfonamide isoform- or class-selective CAIs is of great interest for targeting enzymes from parasitic bacteria, fungi, or protozoa, which in many cases contain non-α-CAs (which in turn are present in the vertebrate hosts, including humans, as mentioned above)Citation2–6. Interesting developments have been reported in this field in recent years, in the search of anti-infectives with a new mechanism of action, devoid of the drug resistance problems encountered by many classes of antibiotic, antifungal, and anti-protozoan agentsCitation4,Citation5. Indeed, some hydroxamates or carboxylates showed effective in vitro CA inhibitory properties and also anti-Trypanosoma cruzi, or anti-leishmanial activities ex vivoCitation4. Thus, in the search of isoform- or class-selective CAIs we investigated here a class of recently developed N-hydroxy-ureasCitation14, which incorporate a more elaborated organic scaffold attached to the second nitrogen atom (compared to the simple lead molecule, N-hydroxyurea)Citation1 and which proved to be effective inhibitors of the tumor-associated isoforms hCA IX/XIICitation14, without inhibiting considerably the off-target, house-keeping cytosolic isoforms hCA I and II, which are responsible for the many side effects seen with the sulfonamide type of CAIsCitation2–6.
2. Materials and methods
2.1. Chemistry
Compounds 1–20 were prepared as reported earlierCitation14. Buffers and acetazolamide (AAZ) were commercially available, highest purity reagents from Sigma-Aldrich/Merck, Milan, Italy.
2.2. CA enzyme inhibition assay
An Sx.18Mv-R Applied Photophysics (Oxford, UK) stopped-flow instrument has been used to assay the catalytic activity of various CA isozymes for CO2 hydration reactionCitation15. Phenol red (at a concentration of 0.2 mM) was used as indicator, working at the absorbance maximum of 557 nm, with 10 mM HEPES (pH 7.5, for α- and δ-CAs) or tris (pH 8.3, for β- and γ-CAs) as buffers, 0.1 M sodium sulphate (for maintaining constant ionic strength), following the CA-catalyzed CO2 hydration reaction for a period of 10 s at 25 °C. The CO2 concentrations ranged from 1.7 to 17 mM for the determination of the kinetic parameters and inhibition constants. For each inhibitor at least six traces of the initial 5–10% of the reaction have been used for determining the initial velocity. The uncatalyzed rates were determined in the same manner and subtracted from the total observed rates. Stock solutions of inhibitors (10 mM) were prepared in distilled-deionized water and dilutions up to 1 nM were done thereafter with the assay buffer. Enzyme and inhibitor solutions were pre-incubated together for 15 min (standard assay at room temperature) prior to assay, in order to allow for the formation of the enzyme-inhibitor complex. The inhibition constants were obtained by non-linear least-squares methods using PRISM 3 and the Cheng-Prusoff equation, as reported earlierCitation14,Citation16–22. All CAs were recombinant proteins produced as reported earlier by our groupsCitation16–22.
3. Results and discussion
Bacterial, fungal, protozoan, or other organisms CAs may represent new drug targets for the development of anti-infectives with an alternative mechanism of action to clinically used agents, but this type of research was rather neglected for a long timeCitation4,Citation5. Only in the last several years, mainly our group, cloned and investigated the inhibition of many parasite CAs from various organisms and belonging to a multitude of enzyme classes, providing the proof-of-concept experiments that parasite CA inhibitors may have a significant anti-infective effect, in vitro and in vivo, for many widespread pathogens such as those provoking malariaCitation4,Citation5, Chagas diseaseCitation4,Citation5, LeishmaniaCitation4,Citation5, or Helicobacter pylori infectionCitation23.
The rationale to investigate the new N’-aryl-N-hydroxyureas of compound type 1–20 as inhibitors of bacterial/diatom CAs, is based on the recent reported of Bozdag et al.Citation14 that these compounds act as hCA IX/XII-selective inhibitors over hCA I and II (). In this article we included in the investigations the three CAs from the bacterial pathogen Vibrio cholerae (VchCAα/β/γ)Citation16,Citation17, the two CAs from the oral bacterial pathogen Porphyromonas gingivalis (PgiCAβ/γ)Citation18,Citation24 as well as the uniquely well investigated δ-class CA, TweCAδ, from the diatom Thalassiosira weissflogiiCitation19.
Table 1. Inhibition data of human CA isoforms hCA I, II, IX, and XII with Compounds 1–22 by a stopped flow CO2 hydrase assayCitation15.
Inhibition data of the six CAs mentioned above with Compounds 1–20 and acetazolamide (AAZ) as standard, sulfonamide inhibitor, are shown in . The following structure-activity relationship (SAR) is observed from thee data of :
Table 2. Inhibition of CAs belonging to the α-, β-, γ-, and δ-classes with N-hydroxyureas Compounds 1–20 and the standard sulfonamide inhibitor acetazolamide (AAZ), by a stopped-flow CO2 hydrase assayCitation15.
VchCAα was inhibited by some but not all Compounds 1–20 with KIs in the range of 97.5 nM – 7.26 µM (). The best inhibitors were Compounds 2 and 9 (KIs of 111.5 and 97.5 nM, respectively) and both of them have a Me-Ph moiety in their molecule (Compound 9 has also a second methyl group). It seems that these two substitution patterns of the aromatic ring are particularly effective for inhibiting this enzyme. The nitro-containing derivatives (Compounds 7 and 8), as well as the 2-Me derivative (Compound 3) were the next best VchCAα inhibitors, with KIs < 1 µM, whereas the remaining derivatives (Compounds 1–6) were weaker, micromolar inhibitors. Strangely enough, all Compounds 11–20 showed KIs > 10 µM, which proves that small changes in the substitution pattern at the aromatic ring has dramatic consequences for the CA inhibitory activity.
VchCAβ showed a rather similar behavior, as Compounds 1–10 were effective inhibitors (KIs in the range of 52.5 nM – 1.81 µM), whereas Compounds 11–20 were not inhibitory (KIs > 10 µM). The best inhibitors were Compounds 5–9 (KIs in the range of 52.5 nM – 64.2 nM) and they incorporate nitro, chloro, and 2,5-dimethylphenyl moieties. The position of the R group on the phenyl moiety is crucial, since isomers such as Compounds 4 and 5/6 differ by an order of magnitude in their inhibitory action (). The 4-chloroderivative (Compound 4) is roughly 10 times a weaker VchCAβ inhibitor compared to the 2- or 3-chlorosubstituted isomers (Compounds 5 and 6). Compounds 1–4 were medium potency inhibitors. It should be stressed that many of these N-hydroxyureas were more effective VchCAβ inhibitors compared to acetazolamide (), such as for example Compounds 3 and 5–9.
VchCAγ was generally poorly inhibited by most of the investigated N-hydroxyureas, except for Compounds 8, 9, 13, 14, 18, and 19, which were weak, micromolar inhibitors, KIs of 4.75 – 8.87 µM. The remaining 14 derivatives in the series were not inhibitory at all up to 10 µM concentration of inhibitor in the assay system (). It is in fact know that the active site of γ-CAs is rather shallow compared to the deep ones of the α- and β-class enzymesCitation3.
PgiCAβ was not significantly inhibited by any of the N-hydroxyureas Compounds 1–20 investigated here, which is rather difficult to explain considering the fact that the X-ray crystal structure of this enzyme is unknown. AAZ is on the other hand a medium potency inhibitor of this enzyme, with a KI of 214 nM.
The γ-CA from the same pathogenic bacterium, PgiCAγ, was on the other hand sensitive to inhibition by many of the investigated N-hydroxyureas Compounds 1–20, which showed KIs ranging between 59.8 nM and 6.42 µM (). The best inhibitors were Compounds 8, 9, and 14, with KIs ranging between 59.8 and 84.4 nM. Again they contain nitrophenyl (Compounds 8 and 9) and methylthiol-phenyl (Compound 14) moieties in their molecule, which seem to be the best ones inducing an effective inhibitory activity against this enzyme. These three compounds were also much more effective than acetazolamide as PgiCAγ inhibitors.
TweCAδ was poorly inhibited by Compounds 1–11, whereas Compounds 12–20 showed a more effective inhibitory activity, with KIs of 33.3 nM – 8.74 µM (). The best inhibitors were Compounds 12–14, with KIs of 33.3 – 57.8 nM and they incorporate various R moieties on the aryl fragment (3-methylthio, 2-ethoxy, and 2,5-dimethylphenyl). As for the other enzymes investigated here, the nature of the R moiety and substitution pattern on the aryl fragment are the main factors influencing he biological activity.
The inhibition profile of these six CAs is very different between each other and also considering the human isoforms investigated earlier (hCA I, II, IX and XII)Citation14, making this class of CAIs of particular interest for developing class-selective inhibitors.
4. Conclusions
A series of 20 N’-aryl-N-hydroxyureas possessing a variety of substitution patterns on the aryl fragment of the molecule, was investigated for the inhibition of six CAs belonging to four genetic families, from pathogenic bacteria and nonpathogenic diatoms. The α-/β-CAs from V. cholerae (VchCAα and VchCAβ) were effectively inhibited by some of these derivatives, with KIs in the range of 97.5 nM – 7.26 µM and 52.5 nM – 1.81 µM, respectively, whereas the γ-class enzyme VchCAγ was less sensitive to inhibition (KIs of 4.75 – 8.87 µM). The β-CA from the pathogenic bacterium Porphyromonas gingivalis (PgiCAβ) was not inhibited by these compounds (KIs > 10 µM) whereas the corresponding γ-class enzyme (PgiCAγ) was effectively inhibited (KIs of 59.8 nM – 6.42 µM). The δ-CA from the diatom Thalassiosira weissflogii (TweCAδ) showed effective inhibition with these derivatives (KIs of 33.3 nM – 8.74 µM). As most of these N-hydroxyureas are also ineffective as inhibitors of the human (h) widespread isoforms hCA I and II (KIs > 10 µM), this class of derivatives may lead to the development of CA inhibitors selective for bacterial/diatom enzymes over their human counterparts and thus to anti-infectives or agents with environmental applications.
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No potential conflict of interest was reported by the authors.
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References
- a) Scozzafava A, Supuran CT. Hydroxyurea is a carbonic anhydrase inhibitor. Bioorg Med Chem 2003;11:2241–6. b) Temperini C, Innocenti A, Scozzafava A, Supuran CT. N-hydroxyurea – a versatile zinc binding function in the design of metalloenzyme inhibitors. Bioorg Med Chem Lett 2006;16:4316–20.
- a) Supuran CT. Carbonic anhydrases: from biomedical applications of the inhibitors and activators to biotechnological use for CO2 capture. J Enzyme Inhib Med Chem 2013;28:229–30. b) Supuran CT. How many carbonic anhydrase inhibition mechanisms exist? J Enzyme Inhib Med Chem 2016;31:345–60. c) Alterio V, Fiore AD, D'Ambrosio K, et al. Multiple binding modes of inhibitors to carbonic anhydrases: how to design specific drugs targeting 15 different isoforms? Chem Rev 2012;112:4421–68. d) Abbate F, Winum JY, Potter BV, et al. Carbonic anhydrase inhibitors: X-ray crystallographic structure of the adduct of human isozyme II with EMATE, a dual inhibitor of carbonic anhydrases and steroid sulfatase. Bioorg Med Chem Lett 2004;14:231–4. e) Capasso C, Supuran CT. An overview of the alpha-, beta- and gamma-carbonic anhydrases from Bacteria: can bacterial carbonic anhydrases shed new light on evolution of bacteria? J Enzyme Inhib Med Chem 2015;30:325–32.
- a) Supuran CT. Advances in structure-based drug discovery of carbonic anhydrase inhibitors. Expert Opin Drug Discov.. 2017;12:61–88. b) Supuran CT. Structure and function of carbonic anhydrases. Biochem J 2016;473:2023–32. c) Supuran CT. Carbonic anhydrases: novel therapeutic applications for inhibitors and activators. Nat Rev Drug Discov 2008;7:168–81. d) Neri D, Supuran CT. Interfering with pH regulation in tumours as a therapeutic strategy. Nat Rev Drug Discov 2011;10:767–77. e) Supuran CT, Vullo D, Manole G, et al. Designing of novel carbonic anhydrase inhibitors and activators. Curr Med Chem Cardiovasc Hematol Agents 2004;2:49–68.
- a) D’Ambrosio K, Supuran CT, De Simone G. Are carbonic anhydrases suitable targets to fight protozoan parasitic diseases? Curr Med Chem 2018; doi: 10.2174/0929867325666180326160121 (in press); b) Vermelho AB, Capaci GR, Rodrigues IA, et al. Carbonic anhydrases from Trypanosoma and Leishmania as anti-protozoan drug targets. Bioorg Med Chem 2017;25:1543–55. c) Supuran CT. Inhibition of carbonic anhydrase from Trypanosoma cruzi for the management of Chagas disease: an underexplored therapeutic opportunity. Future Med Chem 2016;8:311–24. d) Syrjänen L, Vermelho AB, Rodrigues Ide A, et al. Cloning, characterization, and inhibition studies of a β-carbonic anhydrase from Leishmania donovani chagasi, the protozoan parasite responsible for leishmaniasis. J Med Chem 2013;56:7372–81.
- a) Capasso C, Supuran CT. Bacterial, fungal and protozoan carbonic anhydrases as drug targets. Expert Opin Ther Targets 2015;19:1689–704. b) Vermelho AB, da Silva Cardoso V, Ricci Junior E, et al. Nanoemulsions of sulfonamide carbonic anhydrase inhibitors strongly inhibit the growth of Trypanosoma cruzi. J Enzyme Inhib Med Chem 2018;33:139–46. c) de Menezes Dda R, Calvet CM, Rodrigues GC, et al. Hydroxamic acid derivatives: a promising scaffold for rational compound optimization in Chagas disease. J Enzyme Inhib Med Chem 2016;31:964–73. d) Nocentini A, Cadoni R, Dumy P, et al. Carbonic anhydrases from Trypanosoma cruzi and Leishmania donovani chagasi are inhibited by benzoxaboroles. J Enzyme Inhib Med Chem 2018;33:286–9. e) Del Prete S, D, Luca V, De Simone G, Supuran CT, et al. Cloning, expression and purification of the complete domain of the η-carbonic anhydrase from Plasmodium falciparum. J Enzyme Inhib Med Chem 2016;31:54–9.
- a) Supuran CT, Capasso C. The η-class carbonic anhydrases as drug targets for antimalarial agents. Expert Opin Ther Targets 2015;19:551–63. b) Vullo D, Del Prete S, Fisher GM, et al. Sulfonamide inhibition studies of the η-class carbonic anhydrase from the malaria pathogen Plasmodium falciparum. Bioorg Med Chem 2015;23:526–31. c) De Simone G, Di Fiore A, Capasso C, Supuran CT. The zinc coordination pattern in the η-carbonic anhydrase from Plasmodium falciparum is different from all other carbonic anhydrase genetic families. Bioorg Med Chem Lett 2015;25:1385–9.
- a) Supuran CT. Carbon- versus sulphur-based zinc binding groups for carbonic anhydrase inhibitors?. J Enzyme Inhib Med Chem 2018;33:485–95. b) Di Fiore A, Maresca A, Supuran CT, De Simone G. Hydroxamate represents a versatile zinc binding group for the development of new carbonic anhydrase inhibitors. Chem Commun (Camb) 2012;48:8838–40. c) Marques SM, Nuti E, Rossello A, et al. Dual inhibitors of matrix metalloproteinases and carbonic anhydrases: iminodiacetyl-based hydroxamate-benzenesulfonamide conjugates. J Med Chem 2008;51:7968–79.
- Carta F, Supuran CT. Diuretics with carbonic anhydrase inhibitory action: a patent and literature review (2005–2013). Expert Opin Ther Pat 2013;23:681–91.
- Masini E, Carta F, Scozzafava A, Supuran CT. Antiglaucoma carbonic anhydrase inhibitors: a patent review. Expert Opin Ther Pat 2013;23:705–16.
- a) Scozzafava A, Supuran CT, Carta F. Antiobesity carbonic anhydrase inhibitors: a literature and patent review. Expert Opin Ther Pat 2013;23:725–35. b) Supuran CT. Carbonic anhydrases and metabolism. Metabolites 2018;8:E25.
- a) Monti SM, Supuran CT, De Simone G. Anticancer carbonic anhydrase inhibitors: a patent review (2008–2013). Expert Opin Ther Pat 2013;23:737–49. b) Supuran CT. Carbonic anhydrase inhibition and the management of hypoxic tumors. Metabolites 2017;7:E48. c) Ward C, Langdon SP, Mullen P, et al. New strategies for targeting the hypoxic tumour microenvironment in breast cancer. Cancer Treat Rev 2013;39:171–9. d) Garaj V, Puccetti L, Fasolis G, et al. Carbonic anhydrase inhibitors: novel sulfonamides incorporating 1,3,5-triazine moieties as inhibitors of the cytosolic and tumour-associated carbonic anhydrase isozymes I, II and IX. Bioorg Med Chem Lett 2005;15:3102–8. e) Casey JR, Morgan PE, Vullo D, et al. Carbonic anhydrase inhibitors. Design of selective, membrane-impermeant inhibitors targeting the human tumor-associated isozyme IX. J Med Chem 2004;47:2337–47.
- a) Supuran CT. Carbonic anhydrase inhibition and the management of neuropathic pain. Expert Rev Neurother 2016;16:961–8. b) Di Cesare Mannelli L, Micheli L, Carta F, et al. Carbonic anhydrase inhibition for the management of cerebral ischemia: in vivo evaluation of sulfonamide and coumarin inhibitors. J Enzyme Inhib Med Chem 2016;31:894–9.
- a) Margheri F, Ceruso M, Carta F, et al. Overexpression of the transmembrane carbonic anhydrase isoforms IX and XII in the inflamed synovium. J Enzyme Inhib Med Chem 2016;31(sup 4):60–3. b) Bua S, Di Cesare Mannelli L, Vullo D, et al. Design and synthesis of novel nonsteroidal anti-inflammatory drugs and carbonic anhydrase inhibitors hybrids (NSAIDs-CAIs) for the treatment of rheumatoid arthritis. J Med Chem 2017;60:1159–70.
- Bozdag M, Carta F, Angeli A, et al. Synthesis of N'-phenyl-N-hydroxyureas and investigation of their inhibitory activities on human carbonic anhydrases. Bioorg Chem 2018;78:1–6.
- Khalifah RG. The carbon dioxide hydration activity of carbonic anhydrase I. Stop-flow kinetic studies on the native human isoenzymes B and C. J Biol Chem 1971;246:2561–73.
- a) De Vita D, Angeli A, Pandolfi F, et al. Inhibition of the α-carbonic anhydrase from Vibrio cholerae with amides and sulfonamides incorporating imidazole moieties. J Enzyme Inhib Med Chem 2017;32:798–804. b) Del Prete S, Vullo D, De Luca V, et al. Sulfonamide inhibition studies of the β-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae. Bioorg Med Chem 2016;1115–20. 2, c) Del Prete S, Isik S, Vullo D, et al. DNA cloning, characterization, and inhibition studies of an α-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae. J Med Chem 2012;55:10742–8.
- a) Del Prete S, Vullo D, De Luca V, et al. Anion inhibition profiles of α-, β- and γ-carbonic anhydrases from the pathogenic bacterium Vibrio cholerae. Bioorg Med Chem 2016;24:3413–7. b) Angeli A, Del Prete S, Osman SM, et al. Activation studies of the α- and β-carbonic anhydrases from the pathogenic bacterium Vibrio cholerae with amines and amino acids. J Enzyme Inhib Med Chem 2018;33:227–33.
- a) Alafeefy AM, Ceruso M, Al-Tamimi AM, et al. Inhibition studies of quinazoline-sulfonamide derivatives against the γ-CA (PgiCA) from the pathogenic bacterium, Porphyromonas gingivalis. J Enzyme Inhib Med Chem 2015;30:592–6. b) Del Prete S, Vullo D, D, Luca V, et al. Biochemical characterization of recombinant β-carbonic anhydrase (PgiCAb) identified in the genome of the oral pathogenic bacterium Porphyromonas gingivalis. J Enzyme Inhib Med Chem 2015;30:366–70. c) Del Prete S, De Luca V, Vullo D, et al. Biochemical characterization of the γ-carbonic anhydrase from the oral pathogen Porphyromonas gingivalis, PgiCA. J Enzyme Inhib Med Chem 2014;29:532–7.
- a) Del Prete S, Vullo D, De Luca V, et al. Biochemical characterization of the δ-carbonic anhydrase from the marine diatom Thalassiosira weissflogii, TweCA. J Enzyme Inhib Med Chem 2014;29:906–11. b) Bua S, Bozdag M, Del Prete S, et al. Mono- and di-thiocarbamate inhibition studies of the δ-carbonic anhydrase TweCAδ from the marine diatom Thalassiosira weissflogii. J Enzyme Inhib Med Chem 2018;33:707–13.
- a) Diaz JR, Fernández Baldo M, Echeverría G, et al. A substituted sulfonamide and its Co (II), Cu (II), and Zn (II) complexes as potential antifungal agents. J Enzyme Inhib Med Chem 2016;31:51–62. b) Menchise V, De Simone G, Alterio V, et al. Carbonic anhydrase inhibitors: stacking with Phe131 determines active site binding region of inhibitors as exemplified by the X-ray crystal structure of a membrane-impermeant antitumor sulfonamide complexed with isozyme II. J Med Chem 2005;48:5721–7. c) Supuran CT, Mincione F, Scozzafava A, et al. Carbonic anhydrase inhibitors-part 52. Metal complexes of heterocyclic sulfonamides: a new class of strong topical intraocular pressure-lowering agents in rabbits. Eur J Med Chem 1998;33:247–54. d) Garaj V, Puccetti L, Fasolis G, et al. Carbonic anhydrase inhibitors: novel sulfonamides incorporating 1,3,5-triazine moieties as inhibitors of the cytosolic and tumour-associated carbonic anhydrase isozymes I, II and IX. Bioorg Med Chem Lett 2005;15:3102–8. e) Şentürk M, Gülçin İ, Beydemir Ş, et al. In vitro inhibition of human carbonic anhydrase I and II isozymes with natural phenolic compounds. Chem Biol Drug Des 2011;77:494–9. f) Fabrizi F, Mincione F, Somma T, et al. A new approach to antiglaucoma drugs: carbonic anhydrase inhibitors with or without NO donating moieties. Mechanism of action and preliminary pharmacology. J Enzyme Inhib Med Chem 2012;27:138–47.
- a) Krall N, Pretto F, Decurtins W, et al. A small-molecule drug conjugate for the treatment of carbonic anhydrase IX expressing tumors. Angew Chem Int Ed Engl 2014;53:4231–5. b) Rehman SU, Chohan ZH, Gulnaz F, Supuran CT. In-vitro antibacterial, antifungal and cytotoxic activities of some coumarins and their metal complexes. J Enzyme Inhib Med Chem 2005;20:333–40. c) Clare BW, Supuran CT. Carbonic anhydrase activators. 3: structure‐activity correlations for a series of isozyme II activators. J Pharm Sci 1994;83:768–73. d) Dubois L, Peeters S, Lieuwes NG, et al. Specific inhibition of carbonic anhydrase IX activity enhances the in vivo therapeutic effect of tumor irradiation. Radiother Oncol 2011;99:424–31. e) Chohan ZH, Munawar A, Supuran CT, Transition metal ion complexes of Schiff-bases. Synthesis, characterization and antibacterial properties. Met Based Drugs 2001;8:137–43. f) Zimmerman SA, Ferry JG, Supuran CT, Inhibition of the archaeal β-class (Cab) and γ-class (Cam) carbonic anhydrases. Curr Top Med Chem 2007;7:901–8. g) Bayram E, Senturk M, Kufrevioglu OI, Supuran CT. In vitro inhibition of salicylic acid derivatives on human cytosolic carbonic anhydrase isozymes I and II. Bioorg Med Chem 2008;16:9101–5.
- a) Supuran CT, Nicolae A, Popescu A. Carbonic anhydrase inhibitors. Part 35. Synthesis of Schiff bases derived from sulfanilamide and aromatic aldehydes: the first inhibitors with equally high affinity towards cytosolic and membrane-bound isozymes. Eur J Med Chem 1996;31:431–8. b) Pacchiano F, Aggarwal M, Avvaru BS, et al. Selective hydrophobic pocket binding observed within the carbonic anhydrase II active site accommodate different 4-substituted-ureido-benzenesulfonamides and correlate to inhibitor potency. Chem Commun (Camb) 2010;46:8371–3. c) Ozensoy Guler O, Capasso C, Supuran CT. A magnificent enzyme superfamily: carbonic anhydrases, their purification and characterization. J Enzyme Inhib Med Chem 2016;31:689–94. d) De Simone G, Langella E, Esposito D, et al. Insights into the binding mode of sulphamates and sulphamides to hCA II: crystallographic studies and binding free energy calculations. J Enzyme Inhib Med Chem 2017;32:1002–11. e) Winum JY, Temperini C, El Cheikh K, et al. Carbonic anhydrase inhibitors: clash with Ala65 as a means for designing inhibitors with low affinity for the ubiquitous isozyme II, exemplified by the crystal structure of the topiramate sulfamide analogue. J Med Chem 2006;49:7024–31.
- a) Modak JK, Liu YC, Supuran CT, Roujeinikova A. Structure-activity Relationship for sulfonamide inhibition of Helicobacter pylori α-carbonic anhydrase. J Med Chem 2016;59:11098–109. b) Buzás GM, Supuran CT. The history and rationale of using carbonic anhydrase inhibitors in the treatment of peptic ulcers. In memoriam Ioan Puşcaş (1932–2015). J Enzyme Inhib Med Chem 2016;31:527–33. c) Supuran CT. Bacterial carbonic anhydrases as drug targets: toward novel antibiotics? Front Pharmacol 2011;2:34. d) Nishimori I, Onishi S, Takeuchi H, Supuran CT. The alpha and beta classes carbonic anhydrases from Helicobacter pylori as novel drug targets. Curr Pharm Des 2008;14:622–30. e) Chohan ZH, Supuran CT, Scozzafava A. Metal binding and antibacterial activity of ciprofloxacin complexes. J Enzyme Inhib Med Chem 2005;20:303–7.
- Supuran CT, Capasso C. Carbonic anhydrase from Porphyromonas Gingivalis as a drug target. Pathogens 2017;6:30.