Synthesis, biological evaluation, and in silico studies of potential activators of apoptosis and carbonic anhydrase inhibitors on isatin-5-sulfonamide scaffold

Synthesis and evaluation of sulfonamide derivatives of quinoxaline 1,4-dioxides as carbonic anhydrase inhibitors

A series of sulfonamide-derived quinoxaline 1,4-dioxides were synthesized and evaluated as inhibitors of carbonic anhydrases (CA) with antiproliferative potency. Overall, the synthesized compounds demonstrated good inhibitory activity against four CA isoforms. Compound 7g exhibited favorable potency in inhibiting a CA IX isozyme with a K i value of 42.2 nM compared to the reference AAZ (K i = 25.7 nM). Nevertheless, most of the synthesized compounds have their highest activity against CA I and CA II isoforms over CA IX and CA XII. A molecular modeling study was used for an estimation of the binding mode of the selected ligand 7g in the active site of CA IX. The most active compounds (7b, 7f, 7h, and 18) exhibited significant antiproliferative activity against MCF-7, Capan-1, DND-41, HL60, and Z138 cell lines, with IC50 values in low micromolar concentrations. Moreover, derivatives 7a, 7e, and 8g showed similar hypoxic cytotoxic activity and selectivity compared to tirapazamine (TPZ) against adenocarcinoma cells MCF-7. The structure-activity relationships analysis revealed that the presence of a halogen atom or a sulfonamide group as substituents in the phenyl ring of quinoxaline-2-carbonitrile 1,4-dioxides was favorable for overall cytotoxicity against most of the tested cancer cell lines. Additionally, the presence of a carbonitrile fragment in position 2 of the heterocycle also had a positive effect on the antitumor properties of such derivatives against the majority of cell lines. The most potent derivative, 3-trifluoromethylquinoxaline 1,4-dioxide 7h, demonstrated higher or close antiproliferative activity compared to the reference agents, such as doxorubicin, and etoposide, with an IC50 range of 1.3-2.1 μM. Analysis of the obtained results revealed important patterns in the structure-activity relationship. Moreover, these findings highlight the potential of selected lead sulfonamides on the quinoxaline 1,4-dioxide scaffold for further in-depth evaluation and development of chemotherapeutic agents targeting carbonic anhydrases.

Chemistry of heterocycles as carbonic anhydrase inhibitors: A pathway to novel research in medicinal chemistry review

Nowadays, the scientific community has focused on dealing with different kinds of diseases by exploring the chemistry of various heterocycles as novel drugs. In this connection, medicinal chemists identified carbonic anhydrases (CA) as one of the biologically active targets for curing various diseases. The widespread distribution of these enzymes and the high degree of homology shared by the different isoforms offer substantial challenges to discovering potential drugs. Medicinal and synthetic organic chemists have been continuously involved in developing CA inhibitors. This review explored the chemistry of different heterocycles as CA inhibitors using the last 11 years of published research work. It provides a pathway for young researchers to further explore the chemistry of a variety of synthetic as well as natural heterocycles as CA inhibitors.

Novel sulfonamide-phosphonate conjugates as carbonic anhydrase isozymes inhibitors

The three-components one-pot Kabachnik-Fields reaction of sulfapyridine, diethyl phosphite, and aldehyde under thermal catalysis reaction condition in the presence of bismuth (III) triflate as a catalyst afford the corresponding sulfonamide-phosphonates (3a-3p) in good to excellent yields (78%-91%). The structures of the new synthesized compounds were elucidated and confirmed by variable spectroscopic studies. Single crystal X-ray studies for 3a, 3d, and 3i verified the proposed structure. The newly developed sulfonamide-phosphonates were evaluated for their inhibitory properties against four isoforms of human carbonic anhydrase (hCA I, II, IX, and XII). The results demonstrated that they exhibited greater potency in inhibiting hCA XII compared to hCA I, II, and IX, with Ki ranging from 5.1 to 51.1 nM. Compounds 3l and 3p displayed the highest potency, exhibiting selectivity ratios of I/XII >298.7 and 8.5, and II/XII ratios of 678.1 and 142.1, respectively. Molecular docking studies were conducted to explore their binding patterns within the binding pocket of CA XII. The results revealed that the sulfonamide NH group coordinated with the Zn2+ ion, and hydrogen bond interactions were observed with residue Thr200. Additionally, hydrophobic interactions were identified between the benzenesulfonamide phenyl ring and Leu198. Compounds 3p and 3l exhibited an additional hydrogen bonding interaction with other amino acid residues. These supplementary interactions may contribute to the enhanced potency and selectivity of these compounds toward the CA XII isoform.

Visible-Light-Induced Decarboxylative Aminosulfonylation of (Hetero)aryl Carboxylic Oxime Esters

Sulfonamides are important structures in pharmaceuticals, agrochemicals, and organocatalysts, yet the rapid and benign synthesis of these compounds is still a great challenge. Herein we report a photoinduced method for synthesizing sulfonamides from (hetero)aryl carboxylic acid oxime esters. This reaction proceeds via one-pot cascade radical-radical cross-coupling by energy-transfer-mediated photocatalysis. A wide substrate scope including (hetero)aryl substrates and late-stage modification of pharmaceutical molecular entities reveal its generality.

Synthesis and Biological Evaluation of Chalconesulfonamides: En Route to Proapoptotic Agents with Antiestrogenic Potency

Breast and other estrogen receptor α-positive cancers tend to develop resistance to existing drugs. Chalcone derivatives possess anticancer activity based on their ability to form covalent bonds with targets acting as Michael acceptors. This study aimed to evaluate the anticancer properties of a series of chalcones (7a-l) with a sulfonamide group attached to the vinyl ketone moiety. Chalconesulfonamides showed a potent antiproliferative effect at low micromolar concentrations against several cancer cell lines, including ERα-positive 4-hydroxytamoxifen-resistant MCF7/HT2. Immunoblotting of samples treated with the lead compound 7e revealed its potent antiestrogenic activity (ERα/GREB1 axis) and induction of PARP cleavage (an apoptosis marker) in breast cancer cells. The obtained compounds represent a promising basis for further development of targeted drugs blocking hormone pathways in cancer cells.

Synthesis, biological evaluation and molecular docking studies of novel 1,3,4-thiadiazoles as potential anticancer agents and human carbonic anhydrase inhibitors

Thiosemicarbazide and also 1,3,4-thiadiazole derivatives have been garnering substantial attention from researchers worldwide due to their expansive range of biological activities, encompassing antimicrobial, anti-inflammatory, and anticancer properties. Herein, we embarked on a comprehensive investigation in this study, introducing a novel series of thiosemicarbazides (3a-3i) and their corresponding 1,3,4-thiadiazole (4a-4i) derivatives. The compounds were meticulously designed, synthesized, and subjected to meticulous characterization using various spectroscopic methods such as FT-IR, 1H-NMR, 13C-NMR, and elemental analysis. Afterward, their potential anti-proliferative effectiveness was assessed using MTT assay against two cancer cell lines (U87 and HeLa) and normal fibroblast cells (L929). Among the compounds, 4d showed the highest cytotoxic activity against U87 and 4i against HeLa. Compound 3b exhibited selective cytotoxic activity against both cancer cells. Among the molecules with selective activity against the U87 cell line; 3a, 3b, 4d and 4e were further evaluated by caspase-3 activity levels, Bax and Bcl-2 protein expression, and total oxidant status assay. Besides, carbonic anhydrase IX activity studies were also performed in order to understand the underlying mechanism of action. The results indicated that compound 4e showed higher efficacy than standard acetazolamide (IC50 = 0.58 ± 0.02 µM) with an IC50 value of 0.03 ± 0.01 µM. Furthermore, molecular docking studies were carried out using carbonic anhydrase IX crystals to determine the compound's interactions with the enzyme's active sites. This comprehensive investigation sheds light on the intricate interplay between molecular structure and biological activity, providing valuable insights into the therapeutic potential of these compounds.

Acetylphenyl-substituted imidazolium salts: synthesis, characterization, in silico studies and inhibitory properties against some metabolic enzymes

Herein, we present how to synthesize thirteen new 1-(4-acetylphenyl)-3-alkylimidazolium salts by reacting 4-(1-H-imidazol-1-yl)acetophenone with a variety of benzyl halides that contain either electron-donating or electron-withdrawing groups. The structures of the new imidazolium salts were conformed using different spectroscopic methods (1H NMR, 13C NMR, 19F NMR, and FTIR) and elemental analysis techniques. Furthermore, these compounds' the carbonic anhydrase (hCAs) and acetylcholinesterase (AChE) enzyme inhibition activities were investigated. They showed a highly potent inhibition effect toward AChE and hCAs with Ki values in the range of 8.30 ± 1.71 to 120.77 ± 8.61 nM for AChE, 16.97 ± 2.04 to 84.45 ± 13.78 nM for hCA I, and 14.09 ± 2.99 to 69.33 ± 17.35 nM for hCA II, respectively. Most of the synthesized imidazolium salts appeared to be more potent than the standard inhibitor of tacrine (TAC) against AChE and Acetazolamide (AZA) against CA. In the meantime, to prospect for potential synthesized imidazolium salt inhibitor(s) against AChE and hCAs, molecular docking and an ADMET-based approach were exerted.

Synthesis, crystallographic, DNA binding, and molecular docking/dynamic studies of a privileged chalcone-sulfonamide hybrid scaffold as a promising anticancer agent

In the present study, a drug-like molecular hybrid structure between chalcone and sulfonamide moieties was synthesized and characterized. The structural peculiarities of the synthesized hybrid were further verified by means of single crystal X-ray crystallography. Furthermore, its biological activity as an anticancer agent was evaluated. The synthesized model of chalcone-sulfonamide hybrid 3 was found to have potent anticancer properties against the studied cancer cell lines. Hence, the in vitro binding interaction of hybrid 3 with Calf thymus DNA (CT-DNA) was studied at a simulated physiological pH to confirm its anticancer activity for the first time. This was investigated by applying different spectroscopic techniques, ionic strength measurements, viscosity measurements, thermodynamics, molecular dynamic simulation and molecular docking studies. The obtained results showed a clear binding interaction between hybrid 3 and CT-DNA with a moderate affinity via a minor groove binding mechanism. The binding constant (Kb) at 298 K calculated from the Benesi-Hildebrand equation was found to be 3.49 × 104 M-1. The entropy and enthalpy changes (ΔS0 and ΔH0) were 204.65 J mol-1 K-1 and 35.08 KJ mol-1, respectively, indicating that hydrophobic interactions constituted the major binding forces. The results obtained from molecular docking and dynamic simulation studies confirmed the minor groove binding interaction and the stability of the formed complex. This study can contribute to further understanding of the molecular mechanism of hybrid 3 as a potential antitumor agent and can also guide future clinical and pharmacological studies for rational drug design with enhanced or more selective activity and greater efficacy.[Figure: see text]Communicated by Ramaswamy H. Sarma.

Tail approach synthesis of triazolylthiazolotriazole bearing benzenesulfonamides as carbonic anhydrase inhibitors capable of inducing apoptosis

Inhibition of human carbonic anhydrase (hCA) isoform IX with concurrent induction of apoptosis is a promising approach for targeting cancer in humans. Prompted by the scope, novel benzenesulfonamides containing the 1,2,3-triazolylthiazolotriazole tail were synthesized and screened as inhibitors of hCA isoforms I, II, IV, and IX. The tumor-associated isoform hCA IX was strongly inhibited by the sulfonamides reported here with K_I values ranging from 45 nM to 1.882 μM. Overall, nine compounds showed hCA IX inhibition with K_I  < 250 nM. The glaucoma-associated isoform hCA II was moderately inhibited while the cytosolic isoform hCA I and membrane-bound isoform hCA IV were weakly inhibited by the synthesized sulfonamides. Compound 6Ac (K_I  = 3.6 nM) was found to be an almost three times more potent inhibitor of hCA II as compared to the standard drug acetazolamide (K_I  = 12.1 nM). The selective hCA IX inhibitors were further studied for their apoptotic efficacy in goat ovarian cells and showed better results as compared to the control. A comparative study of previously synthesized compounds and molecular docking study of representative compounds revealed some important generalizations that could prove beneficial in further investigations of isoform-selective hCA inhibitors.

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.

Sulfonamide-Derived Dithiocarbamate Gold(I) Complexes Induce the Apoptosis of Colon Cancer Cells by the Activation of Caspase 3 and Redox Imbalance

Two new families of dithiocarbamate gold(I) complexes derived from benzenesulfonamide with phosphine or carbene as ancillary ligands have been synthesized and characterized. In the screening of their in vitro activity on human colon carcinoma cells (Caco-2), we found that the more lipophilic complexes—those with the phosphine PPh₃—exhibited the highest anticancer activity whilst also displaying significant cancer cell selectivity. [Au(S₂CNHSO₂C₆H₅)(PPh₃)] (1) and [Au(S₂CNHSO₂-p-Me-C₆H₄)(IMePropargyl)] (8) produce cell death, probably by intrinsic apoptosis (mitochondrial membrane potential modification) and caspase 3 activation, causing cell cycle arrest in the G1 phase with p53 activation. Besides this, both complexes might act as multi-target anticancer drugs, as they inhibit the activity of the enzymes thioredoxin reductase (TrxR) and carbonic anhydrase (CA IX) with the alteration of the redox balance, and show a pro-oxidant effect.

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.