Investigation of arenesulfonyl-2-imidazolidinones as potent carbonic anhydrase inhibitors

Abdel-Aziz A, Bua S, Nocentini A, Bakheit AH, Alkahtani HM, Hefnawy MM, Supuran CT. Design, synthesis, and carbonic anhydrase inhibition activities of Schiff bases incorporating benzenesulfonamide scaffold: Molecular docking application

In this study, The inhibitory actions of human carbonic anhydrase (CA, EC 4.2.1.1) (hCA) isoforms I, II, IX, and XII are being examined using recently synthesized substituted hydroxyl Schiff derivatives based on the quinazoline scaffold 4-22. Quinazolines 2, 3, 4, 5, 7, 10, 15, and 18 reduce the activity of hCA I isoform effectively to a Ki of 87.6-692.3 nM, which is nearly equivalent to or more potent than that of the standard drug AAZ (Ki, 250.0 nM). Similarly, quinazolines 2, 3, and 5 and quinazoline 14 effectively decrease the inhibitory activity of the hCA II isoform to a KI of 16.9-29.7 nM, comparable to that of AAZ (Ki, 12.0 nM). The hCA IX isoform activity is substantially diminished by quinazolines 2-12 and 14-21 (Ki, 8.9-88.3 nM against AAZ (Ki, 25.0 nM). Further, the activity of the hCA XII isoform is markedly inhibited by the quinazolines 3, 5, 7, 14, and 16 (Ki, 5.4-19.5 nM). Significant selectivity levels are demonstrated for inhibiting tumour-associated isoforms hCA IX over hCAI, for sulfonamide derivatives 6-15 (SI; 10.68-186.29), and 17-22 (SI; 12.52-57.65) compared to AAZ (SI; 10.0). Sulfonamide derivatives 4-22 (SI; 0.50-20.77) demonstrated a unique selectivity in the concurrent inhibition of hCA IX over hCA II compared to AAZ (SI; 0.48). Simultaneously, benzenesulfonamide derivative 14 revealed excellent selectivity for inhibiting hCA XII over hCA I (SI; 60.35), whereas compounds 5-8, 12-14, 16, and 18-22 demonstrated remarkable selectivity for hCA XII inhibitory activity over hCA II (SI; 2.09-7.27) compared to AAZ (SI; 43.86 and 2.10, respectively). Molecular docking studies additionally support 8 to hCA IX and XII binding, thus indicating its potential as a lead compound for inhibitor development.

Antiproliferative Evaluation of Novel 4-Imidazolidinone Derivatives as Anticancer Agent Which Triggers ROS-Dependent Apoptosis in Colorectal Cancer Cell

Colorectal cancer (CRC) is one of the most common causes of cancer-related death worldwide, and more therapies are needed to treat CRC. To discover novel CRC chemotherapeutic molecules, we used a series of previously synthesized novel imidazolidin-4-one derivatives to study their anticancer role in several cancer cell lines. Among these compounds, compound 9r exhibited the best anticancer activity in CRC cell lines HCT116 and SW620. We further investigated the anticancer molecular mechanism of compound 9r. We found that compound 9r induced mitochondrial pathway apoptosis in HCT116 and SW620 cells by inducing reactive oxygen species (ROS) production. Moreover, the elevated ROS generation activated the c-Jun N-terminal kinase (JNK) pathway, which further accelerated apoptosis. N-acetylcysteine (NAC), an antioxidant reagent, suppressed compound 9r-induced ROS production, JNK pathway activation, and apoptosis. Collectively, this research synthesized a series of imidazolidin-4-one derivatives, evaluated their anticancer activity, and explored the molecular mechanism of compound 9r-induced apoptosis in CRC cells. The present results suggest that compound 9r has a potential therapeutic role in CRC. Hence, it deserves further exploration as a lead compound for CRC treatment.

Carbonic Anhydrase Inhibition Activities of Schiff's Bases Based on Quinazoline-Linked Benzenesulfonamide

Human carbonic anhydrase (CA, EC 4.2.1.1) (hCA) isoforms I, II, IX, and XII were investigated for their inhibitory activity with a series of new Schiff's bases based on quinazoline scaffold 4-27. The hCA I isoform was efficiently inhibited by Schiff's bases 4-6, 10-19, 22-27 and had an inhibition constant (Ki) value of 52.8-991.7 nM compared with AAZ (Ki, 250 nM). Amongst the quinazoline derivatives, the compounds 2, 3, 4, 10, 11, 16, 18, 24, 26, and 27 were proven to be effective hCA II inhibitors, with Ki values of 10.8-52.6 nM, measuring up to AAZ (Ki, 12 nM). Compounds 2-27 revealed compelling hCA IX inhibitory interest with Ki values of 10.5-99.6 nM, rivaling AAZ (Ki, 25.0 nM). Quinazoline derivatives 3, 10, 11, 13, 15-19, and 24 possessed potent hCA XII inhibitory activities with K_I values of 5.4-25.5 nM vs. 5.7 nM of AAZ. Schiff's bases 7, 8, 9, and 21 represented attractive antitumor hCA IX carbonic anhydrase inhibitors (CAIs) with K_I rates (22.0, 34.8, 49.2, and 45.3 nM, respectively). Compounds 5, 7, 8, 9, 14, 18, 19, and 21 showed hCA I inhibitors on hCA IX with a selectivity index of 22.46-107, while derivatives 12, 14, and 18 showed selective hCA I inhibitors on hCA XII with a selectivity profile of 45.04-58.58, in contrast to AAZ (SI, 10.0 and 43.86). Compounds 2, 5, 7-14, 19-23, and 25 showed a selectivity profile for hCA II inhibitors over hCA IX with a selectivity index of 2.02-19.67, whereas derivatives 5, 7, 8, 13, 14, 15, 17, 20, 21, and 22 showed selective hCA II inhibitors on hCA XII with a selectivity profile of 4.84-26.60 balanced to AAZ (SI, 0.48 and 2.10).

Effects of hypoxia and hyperoxia on growth parameters and transcription levels of growth, immune system and stress related genes in rainbow trout

Hypoxia and hyperoxia are disparate stressors which can have destructive influences on fish growth and physiology. It is yet to be determined if hypoxia and hyperoxia have a cumulative effect in aquatic ecosystems that affect biological parameters in fish, and to understand if this is associated with gene expression. Here we address whether growth performance and expressions of growth, immune system and stress related genes were affected by hypoxia and hyperoxia in fish. Rainbow trout was chosen as the study organism due to its excellent service as biomonitor. After an acclimatization period, fish were exposed to hypoxia (4.0 ± 0.5 ppm O₂), normoxia (7.5 ± 0.5 ppm O₂) and hyperoxia (12 ± 1.2 ppm O₂) for 28 days. At 6 h, 12 h, 24 h, 48 h, 72 h and 28 days, samples were collected. Hypoxia and hyperoxia negatively affected weight gain (WG), specific growth rate (SGR), survival rate (SR) and feed conversion ratio (FCR). The best WG, SGR, SR and FCR values occurred in fish exposed to normoxia, whereas hypoxia was most suppressive on growth and hyperoxia showed intermediate suppression of these parameters. Gene expression analyses were performed in liver and results revealed that long term exposure caused reduced growth hormone-I (GH-I) and insulin like growth factor I-II (IGF I-II) levels in both hypoxia and hyperoxia-treated fish. Heat shock protein (HSP70) levels increased in both hypoxia and hyperoxia treatment, and both exposures caused elevation of leptin (LEP) expression in long-term exposure. Overall data indicate that both hypoxia and hyperoxia cause stress in rainbow trout and negatively affects growth parameters.

Design, synthesis and molecular modelling studies of some pyrazole derivatives as carbonic anhydrase inhibitors

In this study, newly synthesised compounds 6, 8, 10 and other compounds (1-5, 7 and 9) and their inhibitory properties against the human isoforms hCA I and hCA II were reported for the first time. Compounds 1-10 showed effective inhibition profiles with KI values in the range of 5.13-16.9 nM for hCA I and of 11.77-67.39 nM against hCA II, respectively. Molecular docking studies were also performed with Glide XP to get insight into the inhibitory activity and to evaluate the binding modes of the synthesised compounds to hCA I and II. More rigorous binding energy calculations using MM-GBSA protocol which agreed well with observed activities were then performed to improve the docking scores. Results of in silico calculations showed that all compounds obey drug likeness properties. The new compounds reported here might be promising lead compounds for the development of new potent inhibitors as alternatives to classical hCA inhibitors.

Synthesis, anti-inflammatory, cytotoxic, and COX-1/2 inhibitory activities of cyclic imides bearing 3-benzenesulfonamide, oxime, and β-phenylalanine scaffolds: a molecular docking study

Cyclic imides containing 3-benzenesulfonamide, oxime, and β-phenylalanine derivatives were synthesised and evaluated to elucidate their in vivo anti-inflammatory and ulcerogenic activity and in vitro cytotoxic effects. Most active anti-inflammatory agents were subjected to in vitro COX-1/2 inhibition assay. 3-Benzenesulfonamides (2-4, and 9), oximes (11-13), and β-phenylalanine derivative (18) showed potential anti-inflammatory activities with 71.2-82.9% oedema inhibition relative to celecoxib and diclofenac (85.6 and 83.4%, respectively). Most active cyclic imides 4, 9, 12, 13, and 18 possessed ED50 of 35.4-45.3 mg kg-1 relative to that of celecoxib (34.1 mg kg-1). For the cytotoxic evaluation, the selected derivatives 2-6 and 8 exhibited weak positive cytotoxic effects (PCE = 2/59-5/59) at 10 μM compared to the standard drug, imatinib (PCE = 20/59). Cyclic imides bearing 3-benzenesulfonamide (2-5, and 9), acetophenone oxime (11-14, 18, and 19) exhibited high selectivity against COX-2 with SI > 55.6-333.3 relative to that for celecoxib [SI > 387.6]. β-Phenylalanine derivatives 21-24 and 28 were non-selective towards COX-1/2 isozymes as indicated by their SI of 0.46-0.68.

S-substituted 2-mercaptoquinazolin-4(3H)-one and 4-ethylbenzensulfonamides act as potent and selective human carbonic anhydrase IX and XII inhibitors

We evaluated the hCA (CA, EC 4.2.1.1) inhibitory activity of novel 4-(2-(2-substituted-thio-4-oxoquinazolin-3(4H)-yl)ethyl)benzenesulfonamides (compounds 2–20) towards the isoforms I, II, IX, and XII. hCA Isoforms were effectively inhibited by most of new compounds comparable to those of AAZ. Compounds 2 and 4 showed interestingly efficient and selective antitumor (hCA IX and hCA XII) inhibitor activities (K_Is; 40.7, 13.0, and 8.0, 10.8 nM, respectively). Compounds 4 and 5 showed selective hCA IX inhibitory activity over hCA I (SI; 95 and 24), hCA IX/hCA II (SI; 23 and 5.8) and selective hCA XII inhibitory activity over hCA I (SI; 70 and 44), hCA XII/hCA II, (SI; 17 and 10) respectively compared to AAZ. Compounds 12–17, and 19–20 showed selective inhibitory activity towards hCA IX over hCA I and hCA II, with selectivity ranges of 27–195 and 3.2–19, respectively, while compounds 12, 14–17, and 19 exhibited selective inhibition towards hCA XII over hCA I and hCA II, with selectivity ratios of 48–158 and 5.4–31 respectively, compared to AAZ. Molecular docking analysis was carried out to investigate the selective interactions among the most active derivatives, 17 and 20 and hCAs isoenzymes. Compounds 17 and 20, which are highly selective CA IX and XII inhibitors, exhibited excellent interaction within the putative binding site of both enzymes, comparable to the co-crystallized inhibitors.

Highlights

Quinazoline-linked ethylbenzenesulfonamides inhibiting CA were synthesised.

The new molecules potently inhibited the hCA isoforms I, II, IV, and IX.

Compounds 4 and 5 were found to be selective hCA IX/hCA I and hCA IX/hCA II inhibitors.

Compounds 4 and 5 were found to be selective hCA XII/hCA I and hCA XII/hCA II inhibitors.

Compounds 12–17, 19, and 20 were found to be selective hCA IX/hCA I and hCA IX/hCA II inhibitors.

Compounds 12, 14–17, 19 were found to be selective hCA XII/hCA I and hCA XII/hCA II inhibitors.

Graphical Abstract

Compounds 4 and 5 are selective hCA IX and XII inhibitors over hCA I (selectivity ratios of 95, 23, and 24, 5.8, respectively) and hCA II (selectivity ratios of 70, 17, and 44, 10 respectively). Compounds 12–17, and 19–20 are selective hCA IX inhibitors over hCA I (selectivity ratios of 27-195) and hCA II (selectivity ratios of 3.2-19). Compounds 12, 14–17 and 19 are also selective hCA XII inhibitors over hCA I (selectivity ratios of 48-158) and hCA II (selectivity ratios of 5.4-31).

Exploring structure-activity relationship of S-substituted 2-mercaptoquinazolin-4(3H)-one including 4-ethylbenzenesulfonamides as human carbonic anhydrase inhibitors

Inhibitory action of newly synthesised 4-(2-(2-substituted-thio-4-oxoquinazolin-3(4H)-yl)ethyl)benzenesulfonamides compounds 2-13 against human carbonic anhydrase (CA, EC 4.2.1.1) (hCA) isoforms I, II, IX, and XII, was evaluated. hCA I was efficiently inhibited by compounds 2-13 with inhibition constants (K_Is) ranging from 57.8-740.2 nM. Compounds 2, 3, 4, and 12 showed inhibitory action against hCA II with K_Is between 6.4 and 14.2 nM. CA IX exhibited significant sensitivity to inhibition by derivatives 2-13 with K_I values ranging from 7.1 to 93.6 nM. Compounds 2, 3, 4, 8, 9, and 12 also exerted potent inhibitory action against hCA XII (K_Is ranging from 3.1 to 20.2 nM). Molecular docking studies for the most potent compounds 2 and 3 were conducted to exhibit the binding mode towards hCA isoforms as a promising step for SAR analyses which showed similar interaction with co-crystallized ligands. As such, a subset of these mercaptoquinazolin-4(3H)-one compounds represented interesting leads for developing new efficient and selective carbonic anhydrase inhibitors (CAIs) for the management of a variety of diseases including glaucoma, epilepsy, arthritis and cancer.

Synthesis of N-phenylsulfonamide derivatives and investigation of some esterase enzymes inhibiting properties

In this study, synthesis of nine N-phenylsulfonamide derivatives was designed by starting from aniline, which is the simplest aromatic amine. These compounds were obtained in yields between 69 and 95%. Inhibitory properties of synthesized compounds on carbonic anhydrase I (CA I), CA II isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were investigated. Inhibitors of CA isoenzymes are important therapeutic targets, particularly due to their preventive/activation potential in the treatment of diseases such as edema, glaucoma, cancer and osteoporosis. Cholinesterase inhibitors are valuable compounds that can be used in many different therapeutic applications, including Alzheimer's disease. The compound 8 for CA I, AChE and BChE, 2 for CA II showed a very active inhibition profile (K_I 45.7 ± 0.46 for CA I, 33.5 ± 0.38 nM for CA II, 31.5 ± 0.33 nM for AChE and 24.4 ± 0.29 nM for BChE). The results indicate that these N-phenyl-sulfonamide derivatives are potent CA and cholinesterases and new potential drugs.

Crystal structure of (E)-N′-((4-aminophenyl)sulfonyl)-N,N-dimethylformimidamide, C9H13N3O2S

C9H13N3O2S, monoclinic, P21/c (no. 14), a = 8.0984(4) Å, b = 17.3203(10) Å, c = 9.6802(4) Å, β = 124.031(3)°, V = 1125.26(10) Å3, Z = 4, R gt(F) = 0.0504, wR ref(F 2) = 0.1275, T = 293(2) K.

Synthesis and antitumor activity of bis(arylsulfonyl)dihydroimidazolinone derivatives

A series of novel bis(arylsulfonyl)dihydroimidazolinones with different aryl substitution patterns were readily synthesized and evaluated for their antitumor activities. Some of the newly synthesized compounds exhibited cytotoxicity at micromolar range against multiple cancer cell lines, including A549, HepG2, HuCCA-1, and MOLT-3. The most potent analogue contained pentafluorobenzenesulfonyl groups, which could be chemically elaborated to serve as a potential pharmacophore.

Synthesis, cytotoxic evaluation, and molecular docking studies of novel quinazoline derivatives with benzenesulfonamide and anilide tails: Dual inhibitors of EGFR/HER2

We synthesized a new series of 2-[(3-(4-sulfamoylphenethyl)-4(3H)-quinazolinon-2-yl)thio]anilide derivatives (2-16) and evaluated their cytotoxic activity against breast adenocarcinoma (MCF-7), colorectal adenocarcinoma (HT-29), and acute myeloid leukemia (HL-60 and K562) cells. To reveal their selectivity toward cancer cells, the compounds were also tested against the human fibroblast cell line, MRC-5. Compounds 1-5 exhibited potent cytotoxic activity against the tested cell lines with IC50 values of 0.65-3.86, 0.68-4.60, 0.41-1.45, 0.42-4.07, and 3.77-25.55 μM, respectively compared to sorafenib, the standard drug (IC50 2.50, 2.50, and 3.14 μM against MCF-7, HT-29, and HL60 cells, respectively). Interestingly, compounds 1-5 displayed selectivity toward the cancer cell lines over MRC-5 (IC50 3.77-25.55 μM). These compounds also displayed potent inhibitory activity against EGFR and HER2 kinases (IC50 0.09-0.43 and 0.15-0.33 μM, respectively) compared to the standard drug, sorafenib (IC50 0.11 and 0.13 μM, respectively). Likewise, compounds 1, 4, and 5 showed strong inhibitory activity against VEGFR2 (IC50 0.34, 0.28 and 0.39 μM, respectively) compared to sorafenib (IC50 0.17 μM). We also employed molecular docking to identify the structural features required for the EGFR/HER2 inhibitory activity of the new series. Ultimately, compounds 1, 4, and 5 were demonstrated to be candidates for further preclinical investigations.

Comparison of blood carbonic anhydrase activity of athletes performing interval and continuous running exercise at high altitude

The effects of high-intensity interval and continuous exercise on erythrocytes carbonic anhydrase (CA, EC 4.2.1.1) activity levels were scarcely investigated up until now. Here we present a study focused on the CA activity from erythrocytes of athletes experiencing interval and continuous training for 6 weeks, during cold weather and at high altitude (> 1600 m). We observed a 50% increase in the blood CA activity at the second week after initiation of the training in both interval and continuos running groups, whereas the control group did not experience any variation in the enzyme activity levels. In the trained individuals a mild decrease in their body mass, BMI and an increased [Formula: see text] were also observed. The CA activity returned at the basal values after 4-6 weeks after the training started, probably proving that a metabolic compensation occurred without the need of an enhanced enzyme activity. The unexpected 50% rise of activity for an enzyme which acts as a very efficient catalyst for CO2 hydration/bicarbonate dehydration, such as the blood CA, deserves further investigations for better understanding the physiologic basis of this phenomenon.

Synthesis and comparative carbonic anhydrase inhibition of new Schiff's bases incorporating benzenesulfonamide, methanesulfonamide, and methylsulfonylbenzene scaffolds

Herein, we report the synthesis, characterization, and carbonic anhydrase (CA) inhibition of the newly synthesized Schiff's bases 4-18 with benzenesulfonamide, methanesulfonamide, and methylsulfonylbenzene scaffolds. The compound inhibition profiles against human CA (hCA) isoforms I, II, IX, and XII were compared to those of the standard inhibitors, acetazolamide (AAZ) and SLC-0111 (a CA inhibitor in Phase II clinical trials for the treatment of hypoxic tumors). The hCA I was inhibited by compounds 4a-8a with inhibition constants (KI) in the range 93.5-428.1 nM (AAZ and SLC-0111: KI, 250.0 and 5080.0 nM, respectively). Compounds 4a-8a proved to be effective hCA II inhibitors, with KI ranging from 18.2 to 133.3 nM (AAZ and SLC-0111: KI, 12.0 and 960.0 nM, respectively). Compounds 4a-8a effectively inhibited hCA IX, with KI in the range 8.5-24.9 nM; these values are superior or equivalent to that of AAZ and SLC-0111 (KI, 25.0 and 45.0 nM, respectively). Compounds 4a-8a displayed effective hCA XII inhibitory activity with KI values ranging from 8.6 to 43.2 nM (AAZ and SLC-0111: KI, 5.7 and 4.5 nM, respectively). However, compounds 9b-13b and 14c-18c were found to be micromolar CA inhibitors. For molecular docking studies, compounds 5a, 6a, and 8a were selected.

New anthranilic acid-incorporating N-benzenesulfonamidophthalimides as potent inhibitors of carbonic anhydrases I, II, IX, and XII: Synthesis, in vitro testing, and in silico assessment

The carbonic anhydrase (CA) inhibitory activity of newly synthesized compounds 4-21 against the human CA (hCA) isoforms I, II, IX, and XII was measured and compared to that of standard sulfonamide inhibitors, acetazolamide (AAZ) and SLC-0111. Among this series; benzensulfonamides 6-11 gave the best potent hCA inhibitors with inhibition constants (K_Is) ranging from 81.9 to 456.6 nM (AAZ and SLC-0111: K_Is, 250.0 and 5080 nM, respectively). Compounds 6-11 proved to be effective hCA II inhibitors (K_Is, 8.9-51.5 nM); they were almost equally potent to AAZ (K_I, 12.0 nM) and had superior potency to SLC-0111 (K_I, 960.0 nM). For hCA IX inhibition, compounds 6-11 proved to be potent inhibitors, with K_I values of 3.9-36.0 nM, which were greater than or equal to that of AAZ and greater than that of SLC-0111 (K_Is, 25.0 and 45.0 nM, respectively). For hCA XII inhibitory activity, compounds 6-11 displayed effective inhibition with K_I values ranging from 4.6 to 86.3 nM and were therefore comparable to AAZ and SLC-0111 (K_Is, 5.7 and 4.5 nM, respectively). Molecular docking studies of compounds 6, 7, 10, and 11 were conducted using the crystal structures of hCA isozymes I, II, IX, and XII to study their binding interactions for further lead optimization.

Design, synthesis, and carbonic anhydrase inhibition activity of benzenesulfonamide-linked novel pyrazoline derivatives

Carbonic anhydrases (CA, EC 4.2.1.1) are Zinc metalloenzymes and are present throughout most living organisms. Among the catalytically active isoforms are the cytosolic CA I and II, and tumor-associated CA IX and CA XII. The carbonic anhydrase (CA) inhibitory activities of newly synthesized pyrazoline-linked benzenesulfonamides 18-33 against human CA (hCA) isoforms I, II, IX, and XII were measured and compared with that of acetazolamide (AAZ), a standard inhibitor. Potent inhibitory activity against hCA I was exerted by compounds 18-25, with inhibition constant (KI) values of 87.8-244.1 nM, which were greater than that of AAZ (KI, 250.0 nM). Compounds 19, 21, 22, 29, 30, and 32 were proven to have inhibitory activities against hCA IX with KI values (5.5-37.0 nM) that were more effective than or nearly equal to that of AAZ (KI, 25.0 nM). Compounds 20-22, and 30 exerted potent inhibitory activities (KIs, 7.1-10.1 nM) against hCA XII, in comparison with AAZ (KI, 5.7 nM).

Synthesis, anticancer, apoptosis-inducing activities and EGFR and VEGFR2 assay mechanistic studies of 5,5-diphenylimidazolidine-2,4-dione derivatives: Molecular docking studies

A new series of 5,5-diphenylhydantoin derivatives containing benzylidene or isatin (4–19) was synthesized. Their anticancer activity against HeLa, a cervical cancer cell line, A549, a lung cancer cell line, and MDA-MB-231, a breast cancer cell line, was evaluated. Compounds 13, 16, 17 and 18 exhibited potent anticancer activity with average IC₅₀ values against the tested cell lines of 109, 59, 81 and 113 μM, respectively. Compound 16 showed potent EGFR and VEGFR2 inhibitory activity with IC₅₀ values of 6.17 and 0.09 μM, respectively. In addition, compound 16 induced caspase-dependent apoptosis and reactive oxygen species (ROS) production at 5 and 10 μM. Moreover, a molecular docking simulation was performed for compound 16 and sunitinib to predict the protein-ligand interactions with the active site of VEGFR2.

Synthesis of benzensulfonamides linked to quinazoline scaffolds as novel carbonic anhydrase inhibitors

Carbonic anhydrase (CA) inhibitory activities of newly synthesized quinazoline-linked benzensulfonamides 10-29, 31, 32, 35, 36, and 45-51 against human CA (hCA) isoforms I, II, IX, and XII were measured and compared to that of acetazolamide (AAZ) as a standard inhibitor. Potent selective inhibitory activity against hCA I was exerted by compounds 14, 15, 17, 19, 20, 21, 24, 25, 28, 29, 31, 35, 45, 47, 49, and 51 with inhibition constant (K_Is) values of 39.4-354.7 nM that were nearly equivalent or even greater than that of AAZ (K_I, 250.0 nM). Compounds 15, 20, 24, 28, 29, 45 and 47 proved to have inhibitory activities against hCA II with (K_Is, 0.73-16.5 nM) that were similar or improved to that of AAZ (K_I, 12.0 nM). Compounds 13-29, 31-32, and 45-51 displayed potent hCA IX inhibitory activities (K_Is, 1.6-32.2 nM) that were more effective than or nearly equal to AAZ (K_I, 25.0 nM). Compounds 14, 15, 20, 21, 26, 45, and 47 exerted potent hCA XII inhibitory activities (K_Is, 5.2-9.2 nM), indicating similar CAI activities as compared to that of AAZ (K_I, 5.7 nM).

Synthesis and anti-inflammatory activity of sulfonamides and carboxylates incorporating trimellitimides: Dual cyclooxygenase/carbonic anhydrase inhibitory actions

Trimellitimides 6-21 were prepared and investigated in vivo for anti-inflammatory and ulcerogenic effects and in vitro for cytotoxicity. They were subjected to in vitro cyclooxygenase (COX-1/2) and carbonic anhydrase inhibition protocols. Compounds 6-11 and 18 exhibited anti-inflammatory activities and had median effective doses (ED₅₀) of 34.3-49.8 mg kg^-1 and 63.6-86.6% edema inhibition relative to the reference drug celecoxib (ED₅₀: 33.9 mg kg^-1 and 85.2% edema inhibition). Compounds 6-11 and 18 were weakly cytotoxic at 10 μM against 59 cell lines compared with the reference standard 5-fluorouracil (5-FU). Compounds 6-11 had optimal selectivity against COX-2. The selectivity index (SI) range was >200-490 and was comparable to that for celecoxib [COX-2 (SI) > 416.7]. In contrast, compounds 12, 13, and 16-18 were nonselective COX inhibitors with a selectivity index range of 0.92-0.25. The carbonic anhydrase inhibition assay showed that sulfonamide incorporating trimellitimides 6-11 inhibited the cytosolic isoforms hCA I and hCA II, and tumor-associated isoform hCA IX. They were relatively more susceptible to inhibition by compounds 8, 9, and 11. The K_I ranges were 54.1-81.9 nM for hCA I, 25.9-55.1 nM for hCA II, and 46.0-348.3 nM for hCA IX. © 2018 Elsevier Science. All rights reserved.

Inhibition of the β-carbonic anhydrase from the dandruff-producing fungus Malassezia globosa with monothiocarbamates

A series of monothiocarbamates (MTCs) was investigated for the inhibition of the β-class carbonic anhydrase (CAs, EC 4.2.1.1) from the fungal parasite Malassezia globosa, MgCA. These MTCs incorporate various scaffolds, among which aliphatic amine with 1–4 carbons atom in their molecule, morpholine, piperazine, as well as phenethylamine and benzylamine derivatives. All the reported MTCs displayed a better efficacy in inhibiting MgCA compared to the clinically used sulphonamide drug acetazolamide (K_I of 74 μM), with K_Is spanning between 1.85 and 18.9 μM. The homology model of the enzyme previously reported by us was used to rationalize the results by docking some of these MTCs within the fungal CA active site. This study might be useful to enrich the knowledge of the MgCA inhibition profile, eliciting novel ideas pertaining the design of modulators with potential efficacy in combatting dandruff or other fungal infections.

N-Substituted and ring opened saccharin derivatives selectively inhibit transmembrane, tumor-associated carbonic anhydrases IX and XII

A series of N-substituted saccharins incorporating aryl, alkyl and alkynyl moieties, as well as some ring opened derivatives were prepared and investigated as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1). The widespread cytosolic isoforms CA I and II were not inhibited by these sulfonamides whereas transmembrane, tumor-associated ones were effectively inhibited, with K_Is in the range of 22.1-481nM for CA IX and of 3.9-245nM for hCA XII. Although the inhibition mechanism of these tertiary/secondary sulfonamides is unknown for the moment, the good efficacy and especially selectivity for the inhibition of the tumor-associated over the cytosolic, widespread isoforms, make these derivatives of considerable interest as enzyme inhibitors with various pharmacologic applications.

Dithiocarbamates effectively inhibit the β-carbonic anhydrase from the dandruff-producing fungus Malassezia globosa

A series of dithiocarbamates (DTCs) was investigated for the inhibition of the β-class carbonic anhydrase (CAs, EC 4.2.1.1) from the fungal parasite Malassezia globosa, MgCA, a validated anti-dandruff drug target. These DTCs incorporate various scaffold, among which those of N,N-dimethylaminoethylenediamine, the aminoalcohols with 3-5 carbon atoms in their molecule, 3-amino-quinuclidine, piperidine, morpholine and piperazine derivatives, as well as phenethylamine and its 4-sulfamoylated derivative. Several DTCs resulted more effective in inhibiting MgCA compared to the standard sulfonamide drug acetazolamide (K_I of 74μM), with K_Is ranging between 383 and 6235nM. A computational approach, involving a homology modeling of the enzyme and docking inhibitors within its active site, helped us rationalize the results. This study may contribute to better understand the inhibition profile of MgCA, and offer new ideas for the design of modulators of activity which belong to less investigated chemical classes, thus potentially useful to combat dandruff and other fungal infections.

Discovery of 4-sulfamoyl-phenyl-β-lactams as a new class of potent carbonic anhydrase isoforms I, II, IV and VII inhibitors: The first example of subnanomolar CA IV inhibitors

A series of benzenesulfonamides incorporating 1,3,4-trisubstituted-β-lactam moieties was prepared from sulfanilamide Schiff bases and in situ obtained ketenes, by using the Staudinger cycloaddition reaction. The new compounds were assayed as inhibitors of four human isoforms of the metalloenzyme carbonic anhydrase (hCA, EC 4.2.1.1) involved in various physiological/pathological conditions, hCA I, II, IV and VII. Excellent inhibitory activity was observed against all these isoforms, as follows: hCA I, involved in some eye diseases was inhibited with K_Is in the range of 7.3-917nM; hCA II, an antiglaucoma drug target, with K_Is in the range of 0.76-163nM. hCA IV, an isoform involved in several pathological conditions such as glaucoma, retinitis pigmentosa and edema was potently inhibited by the lactam-sulfonamides, with K_Is in the range of 0.53-51.0nM, whereas hCA VII, a recently validated anti-neuropathic pain target was the most inhibited isoform by these derivatives, with K_Is in the range of 0.68-9.1nM. The structure-activity relationship for inhibiting these CAs with the new lactam-sulfonamides is discussed in detail.

Advances in structure-based drug discovery of carbonic anhydrase inhibitors

INTRODUCTION

The enzyme carbonic anhydrase (CA, EC 4.2.1.1) is found in numerous organisms across the tree of life, with seven distinct classes known to date. CA inhibition can be exploited for the treatment of edema, glaucoma, seizures, obesity, cancer and infectious diseases. A myriad of CA inhibitor (CAI) classes and inhibition mechanisms have been identified over the past decade, mainly through structure-based drug design approaches. Five different CA inhibition mechanisms are presently known. Areas covered: Recent advances in structure-based CAI design are reviewed, with periodic table-based organization of inhibitor classes. Expert opinion: Various structure-based drug design studies have led to deep understanding of factors governing tight binding and selectivity for the various isoforms. Carboxylic acids, phenols, polyamines, diols, borols, boronic acids, coumarins and sulfonamides represent successful stories which led to an anti-tumor sulfonamide in Phase I clinical trials (SLC-0111). For many inhibitor classes, no detailed crystallographic data are available. Detailed structural characterization of all CAI classes may lead to further advances in the field with potential therapeutic implications in the management of indications including neuropathic pain, cerebral ischemia, arthritis and tumor imaging.

Bortezomib inhibits mammalian carbonic anhydrases

We investigated the carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the clinically used antitumor agent bortezomib, a marketed proteasome inhibitor, against all the catalytically active mammalian isoforms CA I-VII, IX, XII-XV. Bortezomib effectively inhibited all these CAs in the micromolar range. hCA II, the physiologically dominant cytosolic isoform showed the highest affinity for the drug, with a K_I of 1.16μM. The cytosolic slow isoform hCA I was also effectively inhibited, with a K_I of 1.29μM, whereas the next best affinity was observed for the membrane-anchored form mCA XV, with a K_I of 2.68μM, followed by two transmembrane isoforms, hCA IX and XIV (K_Is of 3.28-3.38μM). The remaining cytosolic (CA III, VII and XIII), membrane-anchored (CA IV), mitochondrial (CA VA, VB), transmembrane (CA XII) and secreted (CA VI) isoforms were slightly less inhibited by bortezomib compared to isoforms discussed above, with K_Is ranging between 4.38 and 8.45μM. These data may shed some light on possible side effects and novel antitumor mechanisms of action of this drug.

Synthesis 4-[2-(2-mercapto-4-oxo-4H-quinazolin-3-yl)-ethyl]-benzenesulfonamides with subnanomolar carbonic anhydrase II and XII inhibitory properties

Condensation of substituted anthranilic acids with 4-isothiocyanatoethyl-benzenesulfonamide led to series of heterocyclic benzenesulfonamides incorporating 2-mercapto-quinazolin-4-one tails. 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 XII (a transmembrane, tumor-associated enzyme also involved in glaucoma-genesis). The new sulfonamides acted as medium potency inhibitors of hCA I (KIs of 28.5-2954nM), being highly effective as hCA II (KIs in the range of 0.62-12.4nM) and XII (KIs of 0.54-7.11nM) inhibitors. All substitution patterns present in these compounds (e.g., halogens, methyl and methoxy moieties, in positions 6, 7 and/or 8 of the 2-mercapto-quinazolin-4-one ring) led to highly effective hCA II/XII inhibitors. These compounds should thus be of interest as preclinical candidates in pathologies in which the activity of these enzymes should be inhibited, such as glaucoma (CA II and XII as targets) or some tumors in which the activity of isoforms CA II and XII is dysregulated.

Cloning, expression, purification and sulfonamide inhibition profile of the complete domain of the η-carbonic anhydrase from Plasmodium falciparum

We report the cloning, purification and characterization of the full domain of carbonic anhydrase (CA, EC 4.2.1.1) from Plasmodium falciparum, which incorporates 358 amino acid residues (from 181 to 538, in the sequence of this 600 amino acid long protein), called PfCAdom. The enzyme, which belongs to the η-CA class showed the following kinetic parameters: kcat of 3.8×10(5)s(-1) and kcat/Km of 7.2×10(7)M(-1)×s(-1), being 13.3 times more effective as a catalyst compared to the truncated form PfCA. PfCAdom is more effective than the human (h) isoform hCA I, being around 50% less effective compared to hCA II, one of the most catalytically efficient enzymes known so far. Intriguingly, the sulfonamides CA inhibitors generally showed much weaker inhibitory activity against PfCAdom compared to PfCA, prompting us to hypothesize that the 69 amino acid residues insertion present in the active site of this η-CA is crucial for the active site architecture. The best sulfonamide inhibitors for PfCAdom were acetazolamide, methazolamide, metanilamide and sulfanilamide, with KIs in the range of 366-808nM.

Bortezomib inhibits bacterial and fungal β-carbonic anhydrases

Inhibition of the β-carbonic anhydrases (CAs, EC 4.2.1.1) from pathogenic fungi (Cryptococcus neoformans, Candida albicans, Candida glabrata, Malassezia globosa) and bacteria (three isoforms from Mycobacterium tuberculosis, Rv3273, Rv1284 and Rv3588), as well from the insect Drosophila melanogaster (DmeCA) and the plant Flaveria bidentis (FbiCA1) with the boronic acid peptidomimetic proteosome inhibitor bortezomib was investigated. Bortezomib was a micromolar inhibitor of all these enzymes, with KIs ranging between 1.12 and 11.30μM. Based on recent crystallographic data it is hypothesized that the B(OH)2 moiety of the inhibitor is directly coordinated to the zinc ion from the enzyme active site. The class of boronic acids, an under-investigated type of CA inhibitors, may lead to the development of anti-infectives with a novel mechanism of action, based on the pathogenic organisms CA inhibition.

Design, synthesis and biological evaluation of N-(5-methyl-isoxazol-3-yl/1,3,4-thiadiazol-2-yl)-4-(3-substitutedphenylureido) benzenesulfonamides as human carbonic anhydrase isoenzymes I, II, VII and XII inhibitors

A series of N-(5-methyl-isoxazol-3-yl/1,3,4-thiadiazol-2-yl)-4-(3-substitutedphenylureido) benzenesulfonamide derivatives has been designed, synthesized and screened for their in vitro human carbonic anhydrase (hCA; EC 4.2.1.1) inhibition potential. These newly synthesized sulfonamide compounds were assessed against isoforms hCA I, II, VII and XII, with acetazolamide (AAZ) as a reference compound. The majority of these compounds were found quite weak inhibitor against all tested isoforms. Compound 15 showed a modest inhibition potency against hCA I (Ki = 73.7 μM) and hCA VII (Ki = 85.8 μM). Compounds 19 and 25 exhibited hCA II inhibition with Ki values of 96.0 μM and 87.8 μM, respectively. The results of the present study suggest that, although the synthesized derivatives have weak inhibitory potential towards all investigated isoforms, some of them may serve as lead molecules for the further development of selective inhibitors incorporating secondary sulfonamide functionalities, a class of inhibitors for which the inhibition mechanism is poorly understood.

Pyridazinone substituted benzenesulfonamides as potent carbonic anhydrase inhibitors

A series of sulfonamide derivatives (2a-l) incorporating substituted pyridazinone moieties were investigated for the inhibition of two human cytosolic carbonic anhydrase isoforms, hCA I and hCA II. All these compounds, together with the clinically used sulfonamide acetazolamide were investigated as inhibitors of the physiologically relevant isozymes I and II. These sulfonamides showed very strong inhibition against all these isoforms with K(I)'s in the range of 0.98-8.5 nM which makes such molecules possible to be used as leads for discovery of novel effective CA inhibitors targeting other isoforms with medicinal chemistry applications.

How many carbonic anhydrase inhibition mechanisms exist?

Six genetic families of the enzyme carbonic anhydrase (CA, EC 4.2.1.1) were described to date. Inhibition of CAs has pharmacologic applications in the field of antiglaucoma, anticonvulsant, anticancer, and anti-infective agents. New classes of CA inhibitors (CAIs) were described in the last decade with enzyme inhibition mechanisms differing considerably from the classical inhibitors of the sulfonamide or anion type. Five different CA inhibition mechanisms are known: (i) the zinc binders coordinate to the catalytically crucial Zn(II) ion from the enzyme active site, with the metal in tetrahedral or trigonal bipyramidal geometries. Sulfonamides and their isosters, most anions, dithiocarbamates and their isosters, carboxylates, and hydroxamates bind in this way; (ii) inhibitors that anchor to the zinc-coordinated water molecule/hydroxide ion (phenols, carboxylates, polyamines, 2-thioxocoumarins, sulfocoumarins); (iii) inhibitors which occlude the entrance to the active site cavity (coumarins and their isosters), this binding site coinciding with that where CA activators bind; (iv) compounds which bind out of the active site cavity (a carboxylic acid derivative was seen to inhibit CA in this manner), and (v) compounds for which the inhibition mechanism is not known, among which the secondary/tertiary sulfonamides as well as imatinib/nilotinib are the most investigated examples. As CAIs are used clinically in many pathologies, with a sulfonamide inhibitor (SLC-0111) in Phase I clinical trials for the management of metastatic solid tumors, this review updates the recent findings in the field which may be useful for a structure-based drug design approach of more selective/potent modulators of the activity of these enzymes.

Discovering novel carbonic anhydrase type IX (CA IX) inhibitors from seven million compounds using virtual screening and in vitro analysis

Carbonic anhydrase type IX (CA IX) enzyme is mostly over expressed in different cancer cell lines and tumor tissues. Potent CA IX inhibitors can be effective for adjusting the pH imbalance in tumor cells. In the present work, we represented the successful application of high throughput virtual screening (HTVS) of large dataset from ZINC database included of ∼7 million compounds to discover novel inhibitors of CA IX. HTVS and molecular docking were performed using consequence Glide/standard precision (SP), extra precision (XP) and induced fit docking (IFD) molecular docking protocols. For each compound, docking code calculates a set of low-energy poses and then exhaustively scans the binding pocket of the target with small compounds. Novel CA IX inhibitor candidates were suggested based on molecular modeling studies and a few of them were tested using in vitro analysis. These compounds were determined as good inhibitors against human CA IX target with Ki in the range of 0.85-1.58 μM. In order to predict the pharmaceutical properties of the selected compounds, ADME (absorption, distribution, metabolism and excretion) analysis was also carried out.