Novel sulfonamide bearing coumarin scaffolds as selective inhibitors of tumor associated carbonic anhydrase isoforms IX and XII

Synthesis and investigation of selective human carbonic anhydrase IX, XII inhibitors using coumarins bearing a sulfonamide or biotin moiety

The role of carbonic anhydrases isoforms (CAs) IX and XII in the pathogenesis and progression of many types of solid tumors is well known. In this context, selective CA inhibitors (CAIs) towards the mentioned isoforms is a validated strategy for the development of agents to target cancer. For this purpose, novel coumarin derivatives based on the hybridization with arylsulfonamide or biotin scaffolds were synthesized and tested as inhibitors of four different human carbonic anhydrases isoforms: hCA I, II, IX and XII. Coumarin-sulfonamide derived 27, with a thiourea moiety and triazole as linker, showed the highest inhibition activity against hCA XII with an inhibition constant (KI) of 7.5 nM and afforded a very good selectivity over hCA I. Compound 32 was the most potent inhibitor against hCA IX (KI = 6.3 nM), 4-fold stronger than the drug acetazolamide AAZ (KI = 25 nM), used herein as a reference compound, and showed remarkable selectivity over hCA I and II. The coumarin-biotin derivatives 37-39 showed outstanding selectivity towards on-target enzymes (hCA IX and XII) and appear as plausible leads for designing of CAIs.

Mitigating the resistance of MCF-7 cancer cells to Doxorubicin under hypoxic conditions with novel coumarin based carbonic anhydrase IX and XII inhibitors

In the present study, the design and synthesis of novel coumarin derivatives 8a-h, 11a-d and 16a-c as potential selective inhibitors for the tumor associated human carbonic anhydrase isoforms (hCA IX and XII) was reported. All the newly synthesized derivatives showed potent to mild activity against the targeted CA IX (KI = 0.08-9.57 µM), with selectivity indices over CA I (SI = 2.0-21.9) and over CA II (SI = 1.1-15.7). They showed similar activities against CA XII (KI = 0.06-9.48 µM) with selectivity indices over CA I (SI = 1.4-21.2) and CA II (SI = 0.9-15.5). Compound 16b featuring sulfonamide function possessed promising inhibitory activities against the targeted isoforms CA IX and XII with KI values of 0.08 and 0.06 µM, respectively. Interestingly, it was found that using compound 16b at a nontoxic concentration as an adjuvant with Doxorubicin against MCF-7 cells enhanced the cytotoxicity under hypoxia by almost 3.5 folds; IC50 decreased from 25.74 to 7.43 µM. Therefore, compound 16b restored the cytotoxicity of Doxorubicin against MCF-7 cells under hypoxia, almost as normoxia. Furthermore, flow cytometry analysis of a combination treatment of compound 16b and Doxorubicin to the MCF7 cell line revealed an increase in cell cycle arrest at the G2/M phase and a more efficient apoptotic effect than Doxorubicin alone. Furthermore, compound 16b showed no cytotoxicity against normal breast MCF-10A cell line (IC50 = 296.25 µM).

3,3'-((3,4,5-trifluoropHenyl)methylene)bis(4-hydroxy-2H-chromen-2-one) inhibit lung cancer cell proliferation and migration

Lung cancer is a major public health challenge and, despite therapeutic improvements, is the first leading cause of cancer worldwide. The current cure rate from advanced cancer treatment is excessively low. Therefore, it is of great importance to identify novel, potent and less toxic anticancer agents for the treatment of lung cancer. The aim of our research is to synthesize a new biscoumarin 3,3'-((3,4,5-trifluorop -phenyl)methylene)bis(4-hydroxy-2H-chromen-2-one) (C35) as an anticancer agent. C35 was simply prepared by 4-hydroxycoumarin and 3,4,5-trifluorobenzaldehyde under ethanol and its structure was analyzed by spectroscopic analyses. The anti-proliferation effect of C35 was detected using CCK-8 assay. Migration abilities were measured by Transwell assay. The expression of correlated proteins was determined by Western blot. The results showed that C35 displayed strong cytostatic effects on lung cancer cell proliferation. In addition, C35 possessed a significant inhibition of migration by reducing the expression of matrix metalloproteinases-2 (MMP-2) and MMP-9 in lung cancer cells. Furthermore, C35 treatment suppressed the phosphorylation of p38 in lung cancer cells. Moreover, in vivo experiments were carried out, in which we treated Lewis tumor-bearing C57 mice via intraperitoneal injection of C35. Results showed that C35 inhibited tumor growth in vivo. In conclusion, our study demonstrated the anticancer activity of C35 via suppression of lung cancer cell proliferation and migration, which is possibly involved with the inhibition of the p38 pathway.

pH regulators and their inhibitors in tumor microenvironment

As an important characteristic of tumor, acidic tumor microenvironment (TME) is closely related to immune escape, invasion, migration and drug resistance of tumor. The acidity of the TME mainly comes from the acidic products produced by the high level of tumor metabolism, such as lactic acid and carbon dioxide. pH regulators such as monocarboxylate transporters (MCTs), carbonic anhydrase IX (CA IX), and Na+/H+ exchange 1 (NHE1) expel protons directly or indirectly from the tumor to maintain the pH balance of tumor cells and create an acidic TME. We review the functions of several pH regulators involved in the construction of acidic TME, the structure and structure-activity relationship of pH regulator inhibitors, and provide strategies for the development of small-molecule antitumor inhibitors based on these targets.

1,2,3-Triazole-based esters and carboxylic acids as nonclassical carbonic anhydrase inhibitors capable of cathepsin B inhibition

Herein, we report the design and synthesis of a library of 28 new 1,2,3-triazole derivatives bearing carboxylic acid and ester moieties as dual inhibitors of carbonic anhydrase (CA) and cathepsin B enzymes. The synthesised compounds were assayed in vitro for their inhibition potential against four human CA (hCA) isoforms, I, II, IX and XII. The carboxylic acid derivatives displayed low micromolar inhibition against hCA II, IX and XII in contrast to the ester derivatives. Most of the target compounds showed poor inhibition against the hCA I isoform. 4-Fluorophenyl appended carboxylic acid derivative 6c was found to be the most potent inhibitor of hCA IX and hCA XII with a KI value of 0.7 μM for both the isoforms. The newly synthesised compounds showed dual inhibition towards CA as well as cathepsin B. The ester derivatives exhibited higher % inhibition at 10-7  M concentration as compared with the corresponding carboxylic acid derivatives against cathepsin B. The results from in silico studies of the target compounds with the active site of cathepsin B were found in good correlation with the in vitro results. Moreover, two compounds, 5i and 6c, showed cytotoxic activity against A549 lung cancer cells, with IC50 values lower than 100 μM.

Exploring novel anticancer pyrazole benzenesulfonamides featuring tail approach strategy as carbonic anhydrase inhibitors

This study aimed to design potent carbonic anhydrase inhibitors (CAIs) based on pyrazole benzenesulfonamide core. Nine series of substituted pyrazole benzenesulfonamide compounds were synthesized with variable groups like sulphamoyl group as in compounds 4a-e, its bioisosteric carboxylic acid as in compounds 5a-e and 8e, ethyl carboxylate ester as in compounds 6a-e and 9a-e, which were designed as potential prodrugs, isothiazole ring as in compound 7, hydrazide derivative 10e, hydroxamic acid derivatives 11a-e and semicarbazide derivatives 12a-c,e. All the synthesized compounds were investigated for their carbonic anhydrase (CA) inhibitory activity against two human CA isoforms hCA IX and hCA XII and compared to acetazolamide (AAZ). Also, the compounds were assessed for their anticancer activity against 60 cancer cell lines according to the US NCI protocol. Compounds 4b, 5b, 5d, 5e, 6b, 9b, 9e and 11b revealed significant inhibitory activity against both isoforms hCA IX and hCA XII, while 6e, 9d, 11d and 11e showed significant inhibitory activity against hCA XII only compared to acetazolamide as a reference. This would highlight these compounds as promising anticancer drugs. Moreover, compound 6e revealed a remarkable cytostatic activity against CNS cancer cell line (SF-539; TGI = 5.58 μM), renal cancer cell line (786-0; TGI = 4.32 μM) and breast cancer cell line (HS 578 T; TGI = 5.43 μM). Accordingly, compound 6e was subjected to cell cycle analysis and apoptotic assay on the abovementioned cell lines at the specified GI50 (0.45, 0.89 and 1.18 μM, respectively). Also, it revealed the increment of total apoptotic cells percentage in 786-0 (53.19%), SF-539 (46.11%) and HS 578 T (43.55%) relative to the control cells (2.07, 2.64 and 2.52%, respectively). In silico prediction of BBB permeability showed that most of the calculations for compound 6e resulted as BBB (+), which is required for a compound targeting CNS. Further, the interaction of the most active compounds with the key amino acids in the active sites of hCA IX and hCA XII was highlighted by molecular docking analysis.

Potent inhibitors of tumor associated carbonic anhydrases endowed with cathepsin B inhibition

Twenty-one novel extended analogs of acetazolamide were synthesized and screened in vitro for their inhibition efficacy against human carbonic anhydrase (hCA) isoforms I, II, IX, XII, and cathepsin B. The majority of the compounds were found to be effective inhibitors of tumor-associated hCA IX and XII, and poor inhibitors of cytosolic hCA I. Despite the strong to moderate inhibition potential possessed by these compounds toward another cytosolic isoform hCA II, some of them demonstrated better potency against hCA IX and/or XII isoforms as compared to hCA II. Four compounds (11f, 11g, 12c, and 12g) effectively inhibited hCA IX and/or XII isoforms with considerable selectivity over the off-targets hCA I and II. Interestingly, five compounds, including 11f, 11g, 12c, 12d, and 12g, inhibited hCA IX even better than the clinically used acetazolamide. Some of the novel synthesized compounds exhibited higher anti-cathepsin B potential than acetazolamide, with % inhibition of around 50%, at a concentration of 10-7  M. Further, two compounds (12g and 12c) that showed effective and selective inhibition activity profiles against hCA IX and XII were additionally found to be effective inhibitors of cathepsin B.

Coumaryl-sulfonamide moiety: Unraveling their synthetic strategy and specificity toward hCA IX/XII, facilitating anticancer drug development

Currently, cancer is the most grieving threat to society. The cancer-related death rate has had an ascending trend, despite the implementation of numerous treatment strategies or the discovery of an array of potent molecules against several pathways of cancer growth. The need of the hour is to prevent the multidrug resistance toll, and the current efforts have been bestowed upon a versatile small molecule scaffold, coumarin (benz[α]pyrone), a natural compound possessing interesting affinity toward the cancer target human carbonic anhydrase (hCA), focusing on hCA I, II, IX, and XII. Along with coumarin, the age-old known antibacterial drug sulfonamide, when conjugated at positions 3, 7, and 8 of coumarin either with a linker group or as a single entity, has been reported to enhance the affinity of coumarin toward the overexpressed enzymes in tumor cell lines. The sulfonamides have been listed as obsolete drugs due to the severe side effects caused by them; however, their affinity toward the hCA-zinc-binding core has attracted the attention of researchers. Hence, in the process of drug development, coumarin and sulfonamides have remained the choice of last resort. To unveil the synthetic strategy of coumarin-sulfonamide conjugation, their rationale for inhibiting cancer cells/enzymes, and their affinity toward various types of carcinoma have been the sole goal of the researchers. This review specifically focuses on the mechanism of action and the structure-activity relationship through synthetic strategies and the binding affinity of coumaryl-sulfonamide conjugates with the anticancer targets possessing the highest enzyme affinity, since 2008.

Dependence on linkers' flexibility designed for benzenesulfonamides targeting discovery of novel hCA IX inhibitors as potent anticancer agents

Herein we reported the design and synthesis of two series comprising twenty-two benzenesulfonamides that integrate the s-triazine moiety. Target compounds successfully suppressed the hCA IX, with IC₅₀ ranging from 28.6 to 871 nM. Compounds 5d, 11b, 5b, and 7b were the most active analogues, which inhibited hCA IX isoform in the low nanomolar range (K_I = 28.6, 31.9, 33.4, and 36.6 nM, respectively). Furthermore, they were assessed for their cytotoxic activity against a panel of 60 cancer cell lines following US-NCI protocol. According to five-dose assay, 13c showed significant anticancer activity than 5c with GI₅₀-MID values of 25.08 and 189.01 µM, respectively. Additionally, 13c's effects on wound healing, cell cycle disruption, and apoptosis induction in NCI-H460 cancer cells were examined. Further, docking studies combined with molecular dynamic simulation showed a stable complex with high binding affinity of 5d to hCA IX, exploiting a favourable H-bond and lipophilic interactions.HIGHLIGHTSCarbonic anhydrase (CA) inhibitors comprising rigid and flexible linkers were developed.Compound 5d is the most potent CA IX inhibitor in the study (IC50: 28.6 nM).Compounds 5c and 13c displayed the greatest antiproliferative activity towards 60 cell lines.Compound 13c exposed constructive outcomes on normal cell lines, metastasis, and wound healing.Molecular docking and molecular dynamics (MDs) simulation was utilised to study binding mode.

Discovery of 2,4-thiazolidinedione-tethered coumarins as novel selective inhibitors for carbonic anhydrase IX and XII isoforms

Different 2,4-thiazolidinedione-tethered coumarins 5a-b, 10a-n and 11a-d were synthesised and evaluated for their inhibitory action against the cancer-associated hCAs IX and XII, as well as the physiologically dominant hCAs I and II to explore their selectivity. Un-substituted phenyl-bearing coumarins 10a, 10 h, and 2-thienyl/furyl-bearing coumarins 11a-c exhibited the best hCA IX (KIs between 0.48 and 0.93 µM) and hCA XII (KIs between 0.44 and 1.1 µM) inhibitory actions. Interestingly, none of the coumarins had any inhibitory effect on the off-target hCA I and II isoforms. The sub-micromolar compounds from the biochemical assay, coumarins 10a, 10 h and 11a-c, were assessed in an in vitro antiproliferative assay, and then the most potent antiproliferative agent 11a was tested to explore its impact on the cell cycle phases and apoptosis in MCF-7 breast cancer cells to provide more insights into the anticancer activity of these compounds.

An Update on Synthesis of Coumarin Sulfonamides as Enzyme Inhibitors and Anticancer Agents

Coumarin is an important six-membered aromatic heterocyclic pharmacophore, widely distributed in natural products and synthetic molecules. The versatile and unique features of coumarin nucleus, in combination with privileged sulfonamide moiety, have enhanced the broad spectrum of biological activities. The research and development of coumarin, sulfonamide-based pharmacology, and medicinal chemistry have become active topics, and attracted the attention of medicinal chemists, pharmacists, and synthetic chemists. Coumarin sulfonamide compounds and analogs as clinical drugs have been used to cure various diseases with high therapeutic potency, which have shown their enormous development value. The diversified and wide array of biological activities such as anticancer, antibacterial, anti-fungal, antioxidant and anti-viral, etc. were displayed by diversified coumarin sulfonamides. The present systematic and comprehensive review in the current developments of synthesis and the medicinal chemistry of coumarin sulfonamide-based scaffolds give a whole range of therapeutics, especially in the field of oncology and carbonic anhydrase inhibitors. In the present review, various synthetic approaches, strategies, and methodologies involving effect of catalysts, the change of substrates, and the employment of various synthetic reaction conditions to obtain high yields is cited.

Discovery of new carbonic anhydrase IX inhibitors as anticancer agents by toning the hydrophobic and hydrophilic rims of the active site to encounter the dual-tail approach

The hydrophobic and the hydrophilic rims in the active site of human carbonic anhydrase IX (hCA IX) which as well contains a zinc ion as part of the catalytic core, were simultaneously matched to design and synthesize potent and selective inhibitors using a dual-tail approach. Seventeen new compounds, 5a-q, were designed to have the benzenesulfonamide moiety as a zinc binding group. In addition, N-substituted hydrazone and N-phenyl fragments were chosen as the hydrophilic and hydrophobic parts, respectively to achieve favorable interactions with the corresponding halves of the active site. All synthesized compounds successfully suppressed the CA IX, with IC₅₀ values in nanomolar range from 13.3 to 259 nM. Compounds, 5h, 5c, 5m, 5e, and 5k were the top-five compounds efficiently inhibited the tumor-related CA IX isoform in the low nanomolar range (K_I = 13.3, 22.6, 25.8, 26.9 and 27.2 nM, respectively). The target compounds 5a-q developed remarkable selectivity toward the tumor-associated isoforms (hCA IX and XII) over the off-target isoforms (hCA I and II). Furthermore, they were assessed for their anti-proliferative activity, according to US-NCI protocol, against a panel of fifty-nine cancer cell lines. Compounds 5d, 5k and 5o were passed the criteria for activity and scheduled automatically for evaluation at five concentrations with 10-fold dilutions. Compound 5k exhibited significant in vitro anticancer activity with GI₅₀-MID; 8.68 μM compared to compounds 5d and 5o with GI₅₀-MID; 25.76 μM and 34.97 μM respectively. The most selective compounds 5h and 5k were further screened for their in vitro cytotoxic activity against SK-MEL-5, HCC-2998 and RXF 393 cancer cell lines under hypoxic conditions. Furthermore, 5k was screened for cell cycle disturbance, apoptosis induction and intracellular reactive oxygen species (ROS) production in SK-MEL-5 cancer cells. Finally, molecular docking studies were performed to gain insights for the plausible binding interactions and affinities for selected compounds within hCA IX active site.

Synthesis, Crystallographic, Quantum Chemical, Antitumor, and Molecular Docking/Dynamic Studies of 4-Hydroxycoumarin-Neurotransmitter Derivatives

In this contribution, four new compounds synthesized from 4-hydroxycoumarin and tyramine/octopamine/norepinephrine/3-methoxytyramine are characterized spectroscopically (IR and NMR), chromatographically (UHPLC-DAD), and structurally at the B3LYP/6-311++G*(d,p) level of theory. The crystal structure of the 4-hydroxycoumarin-octopamine derivative was solved and used as a starting geometry for structural optimization. Along with the previously obtained 4-hydroxycoumarin-dopamine derivative, the intramolecular interactions governing the stability of these compounds were quantified by NBO and QTAIM analyses. Condensed Fukui functions and the HOMO-LUMO gap were calculated and correlated with the number and position of OH groups in the structures. In vitro cytotoxicity experiments were performed to elucidate the possible antitumor activity of the tested substances. For this purpose, four cell lines were selected, namely human colon cancer (HCT-116), human adenocarcinoma (HeLa), human breast cancer (MDA-MB-231), and healthy human lung fibroblast (MRC-5) lines. A significant selectivity towards colorectal carcinoma cells was observed. Molecular docking and molecular dynamics studies with carbonic anhydrase, a prognostic factor in several cancers, complemented the experimental results. The calculated MD binding energies coincided well with the experimental activity, and indicated 4-hydroxycoumarin-dopamine and 4-hydroxycoumarin-3-methoxytyramine as the most active compounds. The ecotoxicology assessment proved that the obtained compounds have a low impact on the daphnia, fish, and green algae population.

Investigation of 3-sulfamoyl coumarins against cancer-related IX and XII isoforms of human carbonic anhydrase as well as cancer cells leads to the discovery of 2-oxo-2H-benzo[h]chromene-3-sulfonamide - A new caspase-activating proapoptotic agent

Herein we report the synthesis of a set of seventeen 3-sulfonamide substituted coumarin derivatives. Prepared compounds were tested in vitro for inhibition of four physiologically relevant isoforms of the metalloenzyme human carbonic anhydrase (hCA, EC 4.2.1.1). Several coumarin sulfonamides displayed low nanomolar K_I values against therapeutically relevant hCA II, IX, and XII, whereas they did not potently inhibit hCA I. Some of these compounds exerted a concentration-dependent antiproliferative action toward RT4 human bladder cancer and especially A431 human epidermoid carcinoma cell lines. In the meantime, the viability of non-tumorigenic hTERT immortalized human foreskin fibroblast cell line Bj-5ta was not significantly affected by the obtained derivatives. Interestingly, compound 10q (2-oxo-2H-benzo [h]chromene-3-sulfonamide) showed a profound and selective dose-dependent inhibition of A431 cell growth with low nanomolar IC₅₀ values. We demonstrated that 10q possessed a concentration-dependent apoptosis induction activity associated with caspase 3/7 activation in cancer cells. As carbonic anhydrase isoforms in question were not potently inhibited by this compound, its antiproliferative effects likely involve other mechanisms, such as DNA intercalation. Compound 10q clearly represents a viable lead for further development of new-generation anticancer agents.

Thiazole Ring-A Biologically Active Scaffold

BACKGROUND

Thiazole is a good pharmacophore nucleus due to its various pharmaceutical applications. Its derivatives have a wide range of biological activities such as antioxidant, analgesic, and antimicrobial including antibacterial, antifungal, antimalarial, anticancer, antiallergic, antihypertensive, anti-inflammatory, and antipsychotic. Indeed, the thiazole scaffold is contained in more than 18 FDA-approved drugs as well as in numerous experimental drugs.

OBJECTIVE

To summarize recent literature on the biological activities of thiazole ring-containing compounds Methods: A literature survey regarding the topics from the year 2015 up to now was carried out. Older publications were not included, since they were previously analyzed in available peer reviews.

RESULTS

Nearly 124 research articles were found, critically analyzed, and arranged regarding the synthesis and biological activities of thiazoles derivatives in the last 5 years.

Design, synthesis and mechanistic study of new benzenesulfonamide derivatives as anticancer and antimicrobial agents via carbonic anhydrase IX inhibition

Changes in gene expression cause uncontrolled cell proliferation and consequently tumor hypoxia. The tumor cells shift their metabolism to anaerobic glycolysis with a significant modification in pH. Therefore, an over expression of carbonic anhydrase IX (CA IX) genes was detected in many solid tumors. Accordingly, selective inhibition of CA IX can be a useful target for discovering novel antiproliferative agents. The present study described the synthesis of new aryl thiazolone–benzenesulfonamides 4a–j as well as their carbonic anhydrase IX inhibitory effect. All the designed derivatives were evaluated for their anti-proliferative activity against triple-negative breast cancer cell line (as MDA-MB-231) and another breast cancer cell line (MCF-7) in addition to normal breast cell line MCF-10A. Compounds 4b–c, 4e, 4g–h showed significant inhibitory effect against both cancer cell lines at concentration ranges from 1.52–6.31 μM, with a high selectivity against breast cancer cell lines ranges from 5.5 to 17.5 times. Moreover, three sulfonamides derivatives 4e, 4g and 4h showed excellent enzyme inhibition against CA IX with IC₅₀ 10.93–25.06 nM and against CA II with IC₅₀ 1.55–3.92 μM that revealed their remarkable selectivity for CA IX over CA II. Additionally, 4e was able to induce apoptosis in MDA-MB-231 with a significant increase in the annexin V-FITC percent by 22 fold as compared with control. Cellular uptake on MDA-MB-231 cell lines were carried out using HPLC method on the three active compounds (4e, 4g and 4h). On the other hand inhibition of one or more CAs present in bacteria was reported to interfere with bacterial growth. So, the new benzenesulfonamides were evaluated against their antibacterial and anti-biofilm activities. Analogues 4e, 4g and 4h exhibited significant inhibition at 50 μg mL⁻¹ concentration with 80.69%, 69.74% and 68.30% against S. aureus compared to the positive control CIP which was 99.2%, while compounds 4g and 4h showed potential anti-biofilm inhibition 79.46% and 77.52% against K. pneumonia. Furthermore, the designed compounds were docked into CA IX (human) protein (PDB ID: 5FL6) and molecular modeling studies revealed favorable binding interactions for the active inhibitors. Finally, the predictive ADMET studies showed that, compounds 4e, 4g and 4h possessed promising pharmacokinetic properties.

New benzenesulfonamide derivatives as anticancer and antimicrobial agents via CA IX inhibition.

Synthetic Strategies and Computational Inhibition Activity Study for Triazinyl-Substituted Benzenesulfonamide Conjugates with Polar and Hydrophobic Amino Acids as Inhibitors of Carbonic Anhydrases

Various sulfonamide derivatives are intensively studied as anticancer agents owing to their inhibitory activity against human tumor-associated carbonic anhydrase isoforms. In this work, different synthetic procedures for the series of 1,3,5-triazinyl-aminobenzenesulfonamide conjugates with amino acids, possessing polar uncharged, negatively charged, and hydrophobic side chain, were studied and optimized with respect to the yield/purity of the synthesis/product as well as the time of synthetic reaction. These procedures were compared to each other via characteristic HPLC-ESI-DAD/QTOF/MS analytical product profiles, and their benefits as well as limitations were discussed. For new sulfonamide derivatives, incorporating s-triazine with a symmetric pair of polar and some less-polar proteinogenic amino acids, inhibition constants (KIs) against four human carboanhydrases (hCAs), namely cytosolic hCA I, II, transmembrane hCA IV, and the tumor-associated, membrane-bound hCA IX isoforms, were computationally predicted applying various methods of the advanced statistical analysis. Quantitative structure-activity relationship (QSAR) analysis indicated an impressive KI ratio (hCA II/hCA IX) 139.1 and hCA IX inhibition constant very similar to acetazolamide (KI = 29.6 nM) for the sulfonamide derivative disubstituted with Gln. The derivatives disubstituted with Ser, Thr, and Ala showed even lower KIs (8.7, 13.1, and 8.4 nM, respectively).

Coumarin sulfonamide derivatives: An emerging class of therapeutic agents

Coumarin sulfonamide is a heterocyclic pharmacophore and an important structural motif which is a core and integral part of different therapeutic scaffolds and analogues. Coumarin sulfonamides are privileged and pivotal templates which have a broad spectrum of applications in the fields of medicine, pharmacology and pharmaceutics. Coumarin sulfonamide exhibited versatile and myriad biomedical activities such as anti-bacterial, antiviral, antifungal, anti-inflammatory and anti-cancer. This review article focuses on the structural features of coumarin sulfonamide derivatives in the treatment of different lethal diseases on the basis of structure-activity relationships (SAR). The plethora of research cited in this review article summarizes and discusses the various substitutions around the coumarin sulfonamide nucleus which have provided a wide spectrum of biological activities and therapeutic potential that has proved attractive to many researchers looking to exploit the coumarin sulfonamide skeleton for drug discovery and the development of novel therapeutic agents.

Continued exploration and tail approach synthesis of benzenesulfonamides containing triazole and dual triazole moieties as carbonic anhydrase I, II, IV and IX inhibitors

A library of twenty two novel 1,2,3-triazole benzenesulfonamides incorporating thiosemicarbazide, 5(4H)-thione-1,2,4-triazole and variously substituted phenacyl appended 1,2,4-triazole as tail were designed, synthesized and assessed for their efficacy as inhibitors against carbonic anhydrase human (h) isoforms hCA I, II, IV and IX. The physiologically important and off-target cytosolic isoform hCA I was weakly inhibited by most of the newly synthesized sulfonamides while the glaucoma associated isoform hCA II was moderately inhibited with KIs spanning in low nanomolar range (KI = 8.0 nM-0.903 μM). The membrane bound isoform hCA IV, which is known to be involved in glaucoma and retinitis pigmentosa among others, was strongly inhibited by all newly synthesized sulfonamides out of which nine compounds inhibited isoform hCA IV even more effectively as compared to standard drug acetazolamide (AAZ). The membrane bound isoform hCA IX, associated with growth of tumor cells, was moderately inhibited with KIs ranging between 51 nM-3.198 μM. The effect of appending variously substituted tails on heterocyclic moieties over inhibition potential of synthesized sulfonamides is also disclosed which can be of further interest in pharmacological studies for exploring synthesis of isoform selective inhibitors.

Synthesis, biological activity and multiscale molecular modeling studies of bis-coumarins as selective carbonic anhydrase IX and XII inhibitors with effective cytotoxicity against hepatocellular carcinoma

A series of novel bis-coumarin derivatives containing triazole moiety as a linker between the alkyl chains was synthesized and their inhibitory activity against the human carbonic anhydrase (hCA) isoforms I, II, IX and XII were evaluated. In addition, cytotoxic effects of the synthesized compounds on renal adenocarcinoma (769P), hepatocellular carcinoma (HepG2) and breast adeno carcinoma (MDA-MB-231) cell lines were examined. While the hCA I and II isoforms were inhibited in the micromolar range, the tumor-associated isoform hCA IX and XII were inhibited in the high nanomolar range. 4-methyl-7-((1-(12-((2-oxo-2H-chromen-7-yl)oxy)dodecyl)-1H-1,2,3-triazol-4-yl)methoxy)-2H-chromen-2-one (5p) showed the strongest inhibitory activity against hCA IX with the K_i of 144.6 nM and 4-methyl-7-((1-(10-((2-oxo-2H-chromen-7-yl)oxy)decyl)-1H-1,2,3-triazol-4-yl)methoxy)-2H-chromen-2-one (5n) exhibited the highest hCA XII inhibition with the K_i of 71.5 nM. In order to better understand the inhibitory profiles of studied molecules, multiscale molecular modelling approaches were applied. Low energy docking poses of studied molecules at the binding sites of targets have been predicted. In addition, electrostatic potential surfaces (ESP) for binding sites were also generated to understand interactions between proteins and active ligands.

Microwave-assisted synthesis of 1-substituted-1H-benzimidazolium salts: Non-competitive inhibition of human carbonic anhydrase I and II

A series of 1-substituted-1H-benzimidazolium p-toluenesulfonate salts were synthesized in good yields by the reaction of 1-substituted benzimidazole derivatives and p-toluenesulfonic acid under microwave irradiation. Two iodide salts were synthesized by the anion exchange reaction of the corresponding p-toluenesulfonate salt and NaI. All compounds were characterized by ¹ H NMR, ¹³ C NMR, IR, LC-MS spectroscopic methods, and elemental analyses. The crystal structure of 1-methoxyethyl-1H-benzimidazolium p-toluenesulfonate 2d showed that cation and anion are interconnected by N-H···O and C-H···O hydrogen bonds. All compounds were examined as inhibitor of human carbonic anhydrase (hCA) I and II, and all of them inhibited hCA I and hCA II. Kinetic investigation results revealed that these compounds inhibit hCA I and hCA II in a non-competitive manner. The iodide salts had higher inhibitory activity than their corresponding p-toluenesulfonate salts.

Novel coumarin-6-sulfonamides as apoptotic anti-proliferative agents: synthesis, in vitro biological evaluation, and QSAR studies

Herein, we report the synthesis of different novel sets of coumarin-6-sulfonamide derivatives bearing different functionalities (4a, b, 8a-d, 11a-d, 13a, b, and 15a-c), and in vitro evaluation of their growth inhibitory activity towards the proliferation of three cancer cell lines; HepG2 (hepatocellular carcinoma), MCF-7 (breast cancer), and Caco-2 (colon cancer). HepG2 cells were the most sensitive cells to the influence of the target coumarins. Compounds 13a and 15a emerged as the most active members against HepG2 cells (IC50 = 3.48 ± 0.28 and 5.03 ± 0.39 µM, respectively). Compounds 13a and 15a were able to induce apoptosis in HepG2 cells, as assured by the upregulation of the Bax and downregulation of the Bcl-2, besides boosting caspase-3 levels. Besides, compound 13a induced a significant increase in the percentage of cells at Pre-G1 by 6.4-folds, with concurrent significant arrest in the G2-M phase by 5.4-folds compared to control. Also, 13a displayed significant increase in the percentage of annexin V-FITC positive apoptotic cells from 1.75-13.76%. Moreover, QSAR models were established to explore the structural requirements controlling the anti-proliferative activities.

Design and synthesis of novel benzenesulfonamide containing 1,2,3-triazoles as potent human carbonic anhydrase isoforms I, II, IV and IX inhibitors

In a quest to discover new biologically active compounds, a series of twenty novel heterocyclic derivatives substituted at position 5 with -H (7a-7j) or -CF3 (8a-8j), bearing benzenesulfonamide at N-1 position and various aroyl groups at position 4 of the 1,2,3-triazole ring was synthesized and screened for their carbonic anhydrase (CA, EC 4.2.1.1) inhibition potential against four human (h) isoforms hCA I, II, IV and IX. All the compounds (7a-7j and 8a-8j) were synthesized via [3+2] cycloaddition reaction from 4-azidobenzenesulfonamide. Interestingly, compounds 7a-7j were prepared in one pot manner via enaminone intermediate using novel methodology. All the newly synthesized compounds (7a-7j &8a-8j) were found to be excellent inhibitors of edema related isoform hCA I with their inhibition constant (Ki) ranging from 30.1 to 86.8 nM as compared to standard drug acetazolamide (AAZ) with Ki = 250 nM. Further it was found that most of tested compounds were weaker inhibitors of isoform, hCA II although compounds 7b, 7d-7e, 8a, 8d-8f, 8i (mostly with electron withdrawing substituents) have shown better inhibition potential (Ki < 50 nM). Against glaucoma associated hCA IV, compound 7d was found to be better inhibitor (Ki = 52.4 nM) than AAZ (Ki = 74 nM) while against tumor associated hCA IX, all the compounds have shown moderate inhibition potential. Present study have added one more step in exploring the 1,2,3-triazlole moiety in the medicinal field.

Synthesis of novel 4-functionalized 1,5-diaryl-1,2,3-triazoles containing benzenesulfonamide moiety as carbonic anhydrase I, II, IV and IX inhibitors

The design, synthesis and biological evaluation of a library of 1,2,3-triazole carboxylates incorporating carboxylic acid, hydroxymethyl, carboxylic acid hydrazide, carboxamide and benzenesulfonamide moieties is disclosed. All the novel compounds were investigated for their inhibition potential against carbonic anhydrase (CA, EC 4.2.1.1) human (h) isoforms hCA I, II, IV and IX, well established drug targets. The cytosolic isoform hCA I was inhibited with Ki's ranging between 53.2 nM and 7.616 μM whereas the glaucoma associated cytosolic isoform hCA II was inhibited with Ki's in the range 21.8 nM-0.807 μM. The membrane bound isoform hCA IV, involved in glaucoma and retinitis pigmentosa among others, was effectively inhibited by some of these compounds with Ki < 60 nM, better than the reference drug acetazolamide (AAZ). The tumor associated isoform hCA IX, a recently validated antitumor/antimetastatic drug target, was also effectively inhibited by some of the new sulfonamides, which possess thus the potential to be used as tools for exploring in more details the selective inhibition of hCAs involved in various pathologies.

Inhibition of carbonic anhydrase IX targets primary tumors, metastases, and cancer stem cells: Three for the price of one

Human carbonic anhydrase (CA) IX is a tumor-associated protein, since it is scarcely present in normal tissues, but highly overexpressed in a large number of solid tumors, where it actively contributes to survival and metastatic spread of tumor cells. Due to these features, the characterization of its biochemical, structural, and functional features for drug design purposes has been extensively carried out, with consequent development of several highly selective small molecule inhibitors and monoclonal antibodies to be used for different purposes. Aim of this review is to provide a comprehensive state-of-the-art of studies performed on this enzyme, regarding structural, functional, and biomedical aspects, as well as the development of molecules with diagnostic and therapeutic applications for cancer treatment. A brief description of additional pharmacologic applications for CA IX inhibition in other diseases, such as arthritis and ischemia, is also provided.

Synthesis and biological evaluation of benzenesulphonamide-bearing 1,4,5-trisubstituted-1,2,3-triazoles possessing human carbonic anhydrase I, II, IV, and IX inhibitory activity

A library of benzenesulphonamides incorporating 1,2,3-triazole rings functionalised with ester, carboxylic acid, carboxamide, carboxyhydrazide, and hydroxymethyl moieties were synthesised. The carbonic anhydrase (CAs, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against four human (h) isoforms, hCA I, hCA II, hCA IV, and hCA IX. Among them, hCA II and IV are anti-glaucoma drug targets, being involved in aqueous humour secretion within the eye. hCA I was inhibited with Ki's ranging between 8.3 nM and 0.8737 µM. hCA II, the physiologically dominant cytosolic isoform, was excellently inhibited by these compounds, with Ki's in the range of 1.6-9.4 nM, whereas hCA IV was effectively inhibited by most of them, with Ki's in the range of 1.4-55.3 nM. Thirteen of the twenty sulphonamides were found to be excellent inhibitors of tumour associated hCA IX with Ki's ≤ 9.5 nM. Many of the new compounds reported here showed low nM inhibitory action against hCA II, IV, and IX, isoforms involved in glaucoma and some tumours, making them interesting candidates for further medicinal chemistry/pharmacologic studies.

Microwave-assisted synthesis and bioevaluation of new sulfonamides

In this study, 4-[5-(4-hydroxyphenyl)-3-aryl-4,5-dihydro-1H-pyrazol-1-yl]benzenesulfonamide derivatives (8-14) were synthesized for the first time by microwave irradiation and their chemical structures were confirmed by ¹H NMR, ¹³C NMR and HRMS. Cytotoxic activities and inhibitory effects on carbonic anhydrase I and II isoenzymes of the compounds were investigated. The compounds 9 (PSE = 4.2), 12 (PSE = 4.1) and 13 (PSE = 3.9) with the highest potency selectivity expression (PSE) values in cytotoxicity experiments and the compounds 13 (Ki = 3.73 ± 0.91 nM toward hCA I) and 14 (Ki = 3.85 ± 0.57 nM toward hCA II) with the lowest Ki values in CA inhibition studies can be considered as leader compounds for further studies.

Synthesis and carbonic anhydrase inhibitory properties of novel chalcone substituted benzenesulfonamides

Carbonic anhydrases (CAs, EC 4.2.1.1) are crucial metalloenzymes involved in many bioprocesses, through catalysis of the reversible hydration/dehydration process of CO2/HCO3-. The inhibition of human CA isoforms I and II with a new series of sulfonamide derivatives incorporating substituted chalcone moieties were studied in this study. All these newly synthesized sulfonamides demonstrated important inhibitory profiles to these CA isoforms with KIs in the range of 9.88 to 55.43nM, making these compounds interesting leads, with potential applications in medicinal chemistry.

Biological evaluation of some new N-(2,6-dimethoxypyrimidinyl) thioureido benzenesulfonamide derivatives as potential antimicrobial and anticancer agents

A series of novel heterocyclic thioureas 3a-u containing sulfonamide moiety have been synthesized by the condensation of isothiocyanatobenzenesulfonamide 2 with a variety of heterocyclic amines. The newly synthesized heterocyclic thioureas were investigated for their antimicrobial and anticancer activity. The in vitro antibacterial and antifungal activity were done using well diffusion method. Interestingly, compounds 3j and 3m, showed similar or better activity compared with the reference drug against the tested microorganisms. Although, 3j was less active among its analogues to inhibit the breast carcinoma cells, it exhibit strong broad spectrum antimicrobial activities. However, The results of the cytotoxic activity revealed that compound 3p was the most active against the breast carcinoma cell line (MCF-7) giving promising IC50 value of 1.72 μg/mL, compared with reference drug (5-flourouracil) with IC50 value of 4.8 μg/mL. The most potent compounds in cytotoxic activity 3b and 3p were further docked inside the active site of CAIX and were found to exhibit a proper binding with the active site amino acids according to their bond lengths, angles and conformational energy.