Design, synthesis and biological evaluation of coumarin-3-carboxamides as selective carbonic anhydrase IX and XII inhibitors

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).

Multimodal antibacterial potency of newly designed and synthesized Schiff's/Mannich based coumarin derivatives: potential inhibitors of bacterial DNA gyrase and biofilm production

The briskened urge to develop potential antibacterial candidates against multidrug-resistant pathogens has motivated the present research study. Herein, newly synthesized coumarin derivatives with azomethine and amino-methylated as the functional groups have been focused on their antibacterial efficacy. The study proposed two distinct series: 3-acetyl substituted coumarin derivatives, followed by the Schiff base approach (5a-5i), and formaldehyde-secondary cyclic amine-based derivatives (7a-7g), using the Mannich base approach, further the compounds have been confirmed through various spectral studies. Further, target-specific binding affinity has been affirmed via in silico study. In vitro antibacterial study suggested compounds 5d and 5f to be most effective against S. aureus and multidrug-resistant K. pneumoniae, with MIC values of 8 and 16 μg mL-1. Among them, the compounds 5d and 5f showed excellent binding scores against different bacterial gyrase compared to the standard novobiocin. Based on RMRS, RMSF, Rg, and H-bond plots, MD simulation study at 100 ns also suggested better stability of 5d inside gyraseB of E. coli than the complex of E. coli-GyrB-novobiocin. The toxicity and pharmacokinetic profiles showed favorable drug-likeness. Overall, systematic in vitro and in silico assessment suggested that multimodal antibacterial derivatives 5d and 5f strongly inhibit both bacterial DNA gyrase and biofilm formation of drug-resistant pathogens, suggesting their potency in mainstream antibacterial therapy.

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.

Discovery and Mechanistic Studies of Dual-Target Hits for Carbonic Anhydrase IX and VEGFR-2 as Potential Agents for Solid Tumors: X-ray, In Vitro, In Vivo, and In Silico Investigations of Coumarin-Based Thiazoles

A dual-targeting approach is predicted to yield better cancer therapy outcomes. Consequently, a series of coumarin-based thiazoles (5a-h, 6, and 7a-e) were designed and constructed as potential carbonic anhydrase (CA) and VEGFR-2 suppressors. The inhibitory actions of the target compounds were assessed against CA isoforms IX and VEGFR-2. The assay results showed that coumarin-based thiazoles 5a, 5d, and 5e can effectively inhibit both targets. 5a, 5d, and 5e cytotoxic effects were tested on pancreatic, breast, and prostate cancer cells (PANC1, MCF7, and PC3). Further mechanistic investigation disclosed the ability of 5e to interrupt the PANC1 cell progression in the S stage by triggering the apoptotic cascade, as seen by increased levels of caspases 3, 9, and BAX, alongside the Bcl-2 decline. Moreover, the in vivo efficacy of compound 5e as an antitumor agent was evaluated. Also, molecular docking and dynamics displayed distinctive interactions between 5e and CA IX and VEGFR-2 binding pockets.

Design, synthesis and anticancer evaluation of some novel 7-hydroxy-4-methyl-3-substituted benzopyran-2-one derivatives

Aim: 22 derivatives of 7-hydroxy-4-methyl-3-substituted benzopyran-2-one were designed, synthesized and evaluated for their anticancer activity. Materials & methods: The prepared compounds were screened for their cytotoxicity against the MCF-7 breast cancer cell line. The best five were then evaluated against MCF10a to check their safety and then tested for their PI3K and Akt-1 inhibitory action. The best two derivatives were further analyzed through cell cycle analysis, caspase 3/7 activation, increasing BAX level and decreasing BCL-2. Docking and absorption, distribution, metabolism and excretion prediction studies were also performed. Results & conclusion: Compounds 3b, 3c, 3j, 7 and 8 were the most active. Compounds 3c and 8 showed remarkable inhibitory action against PI3K and Akt-1 enzymes, and both are promising candidates for treatment of breast cancer.

Exploring the potency of diazo-coumarin containing hybrid molecules: Selective inhibition of tumor-associated carbonic anhydrase isoforms IX and XII

This study introduces a series of ten hybrid molecules DK(1-10), which combine diazo and coumarin moieties along with diverse aromatic substitutions. The primary objective was to evaluate the inhibitory capabilities of these compounds against four prominent isoforms: the cytosolic hCA I and II, as well as the tumor-associated membrane-bound hCA IX and XII. Impressively, the majority of the tested compounds exhibited significant inhibition activity against the tumor-associated isoforms hCA IX and XII, with KI values ranging from 29.2 to 293.3 nM. Notably, compound DK-8 displayed particularly robust inhibitory activity against the tumor-associated membrane-bound isoforms, hCA IX and XII, yielding KI values of 32.5 and 29.2 nM, respectively. Additionally, another derivative, DK-9, containing a primary sulfonamide, exhibited notable inhibition against hCA XII with a KI value of 36.4 nM. This investigation aimed to explore the structure-activity relationships within these compounds, shedding light on how various substitutions and structural components influence their inhibitory potential. As a result, these compounds present promising candidates for further exploration in medicinal and pharmacological research. Their ability to selectively inhibit specific isoforms, particularly those associated with hypoxic tumors, suggests their potential as foundational compounds for the development of novel therapeutic agents.

1,3-Diaryl Triazenes Incorporating Disulfonamides Show Both Antiproliferative Activity and Effective Inhibition of Tumor-associated Carbonic Anhydrases IX and XII

AIM

The aim of this study was to synthesize a library of novel di-sulfa drugs containing 1,3- diaryltriazene derivatives TS (1-13) by conjugation of diazonium salts of primary sulfonamides with sulfa drugs to investigate the cytotoxic effect of these new compounds in different cancer types and to determine their inhibitory activity against tumor-associated carbonic anhydrases IX and XII.

MATERIALS AND METHODS

A carbonic anhydrase inhibitory activity of the obtained compounds was evaluated against four selected human carbonic anhydrase isoforms (hCA I, hCA II, hCA IX and hCA XII) by a stoppedflow CO2 hydrase assay. In addition, in vitro, cytotoxicity studies were applied by using A549 (lung cancer), BEAS-2B (normal lung), MCF-7 (breast cancer), MDA-MB-231 (breast cancer), CRL-4010 (normal breast epithelium), HT-29 (colon cancer), and HCT -116 (colon cancer) cell lines.

RESULTS

As a result of the inhibition data, the 4-aminobenzenesulfonamide derivatives were more active than their 3-aminobenzenesulfonamide counterparts. More specifically, compounds TS-1 and TS-2, both of which have primary sulfonamides on both sides of the triazene linker, showed the best inhibitory activity against hCA IX with Ki values of 19.5 and 13.7 nM and also against hCA XII with Ki values of 6.6 and 8.3 nM, respectively. In addition, in vitro cytotoxic activity on the human breast cancer cell line MCF-7 showed that some derivatives of di-sulfa triazenes, such as TS-5 and TS-13, were more active than SLC-0111.

CONCLUSION

With the aim of developing more potent and isoform-selective CA inhibitors, these novel hybrid molecules containing sulfa drugs, triazene linkers, and the classical primary sulfonamide chemotype may be considered an interesting example of effective enzyme inhibitors and important anticancer agents.

Umbelliferone and Its Synthetic Derivatives as Suitable Molecules for the Development of Agents with Biological Activities: A Review of Their Pharmacological and Therapeutic Potential

Umbelliferone (UMB), known as 7-hydroxycoumarin, hydrangine, or skimmetine, is a naturally occurring coumarin in the plant kingdom, mainly from the Umbelliferae family that possesses a wide variety of pharmacological properties. In addition, the use of nanoparticles containing umbelliferone may improve anti-inflammatory or anticancer therapy. Also, its derivatives are endowed with great potential for therapeutic applications due to their broad spectrum of biological activities such as anti-inflammatory, antioxidant, neuroprotective, antipsychotic, antiepileptic, antidiabetic, antimicrobial, antiviral, and antiproliferative effects. Moreover, 7-hydroxycoumarin ligands have been implemented to develop 7-hydroxycoumarin-based metal complexes with improved pharmacological activity. Besides therapeutic applications, umbelliferone analogues have been designed as fluorescent probes for the detection of biologically important species, such as enzymes, lysosomes, and endosomes, or for monitoring cell processes and protein functions as well various diseases caused by an excess of hydrogen peroxide. Furthermore, 7-hydroxy-based chemosensors may serve as a highly selective tool for Al3+ and Hg2+ detection in biological systems. This review is devoted to a summary of the research on umbelliferone and its synthetic derivatives in terms of biological and pharmaceutical properties, especially those reported in the literature during the period of 2017-2023. Future potential applications of umbelliferone and its synthetic derivatives are presented.

Synthesis and biological evaluation of new 3-substituted coumarin derivatives as selective inhibitors of human carbonic anhydrase IX and XII

The Carbonic anhydrase isoforms IX and XII play a significant role in regulating the intracellular and extracellular pH in hypoxic tumours abetting the metastasis of solid tumours. Selective and potent inhibitors targeting carbonic anhydrase IX and XII reduce the activity of these isoforms in hypoxic tumours, representing an antitumor and antimetastatic mechanism. Coumarin-based derivatives are selective inhibitors of CA isoforms IX and XII. In this study, we report the design and synthesis of new 3-substituted coumarin derivatives with different functional moieties and their inhibitory activity against various carbonic anhydrase isoforms. We found that the tertiary sulphonamide derivative 6c showed selective inhibition against CA IX with IC₅₀ of 4.1 µM. Similarly, the carbothioamides 7c, 7b and oxime ether derivative 20a exhibited good inhibition against CA IX and CA XII. Additionally, the binding mode was predicted and validated using molecular docking and dynamic simulations.

A Multitarget Approach against Neuroinflammation: Alkyl Substituted Coumarins as Inhibitors of Enzymes Involved in Neurodegeneration

Neurodegenerative disorders (NDs) include a large range of diseases characterized by neural dysfunction with a multifactorial etiology. The most common NDs are Alzheimer's disease and Parkinson's disease, in which cholinergic and dopaminergic systems are impaired, respectively. Despite different brain regions being affected, oxidative stress and inflammation were found to be common triggers in the pathogenesis and progression of both diseases. By taking advantage of a multi-target approach, in this work we explored alkyl substituted coumarins as neuroprotective agents, capable to reduce oxidative stress and inflammation by inhibiting enzymes involved in neurodegeneration, among which are Carbonic Anhydrases (CAs), Monoamine Oxidases (MAOs), and Cholinesterases (ChEs). The compounds were synthesized and profiled against the three targeted enzymes. The binding mode of the most promising compounds (7 and 9) within MAO-A and -B was analyzed through molecular modeling studies, providing and explanation for the different selectivities observed for the MAO isoforms. In vitro biological studies using LPS-stimulated rat astrocytes showed that some compounds were able to counteract the oxidative stress-induced neuroinflammation and hamper interleukin-6 secretion, confirming the success of this multitarget approach.

Selective carbonic anhydrase IX and XII inhibitors based around a functionalized coumarin scaffold

Inhibition of specific carbonic anhydrase (CA) enzymes is a validated strategy for the development of agents to target cancer. The CA isoforms IX and XII are overexpressed in various human solid tumors wherein they play a critical role in regulating extracellular tumor acidification, proliferation, and progression. A series of novel sulfonamides based on the coumarin scaffold were designed, synthesized and characterized as potent and selective CA inhibitors. Selected compounds show significant activity and selectivity over CA I and CA II to target the tumor-associated CA IX and CA XII with high inhibition activity at the single digit nanomolar level. Twelve compounds were identified to be more potent compared with acetazolamide (AAZ) control to inhibit CA IX while one was also more potent than AAZ to inhibit CA XII. Compound 18f (Ki's = 955 nM, 515 nM, 21 nM and 5 nM for CA's I, II, IX, and XII, respectively) is highlighted as a novel CA IX and XII inhibitor for further development.

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.

Targeting carbonic anhydrase IX and XII isoforms with small molecule inhibitors and monoclonal antibodies

Carbonic anhydrases IX and CAXII (CAIX/CAXII) are transmembrane zinc metalloproteins that catalyze a very basic but crucial physiological reaction: the conversion of carbon dioxide into bicarbonate with a release of the proton. CA, especially CAIX and CAXII isoforms gained the attention of many researchers interested in anticancer drug design due to pivotal functions of enzymes in the cancer cell metastasis and response to hypoxia, and their expression restricted to malignant cells. This offers an opportunity to develop new targeted therapies with fewer side effects. Continuous efforts led to the discovery of a series of diverse compounds with the most abundant sulphonamide derivatives. Here we review current knowledge considering small molecule and antibody-based targeting of CAIX/CAXII in cancer.

Novel 3-(6-methylpyridin-2-yl)coumarin-based chalcones as selective inhibitors of cancer-related carbonic anhydrases IX and XII endowed with anti-proliferative activity

Carbonic anhydrases (CAs) are one of the promising targets for the development of anticancer agents. CA isoforms are implicated in various physiological processes and are expressed in both normal and cancerous cells. Thus, non-isoform selective inhibitors are associated with several side effects. Consequently, designing selective inhibitors towards cancer-related hCA IX/XII rather than the ubiquitous cytosolic isozymes hCA I and II is the main research objective in the field. Herein, a new series of 3-(6-methylpyridin-2-yl)coumarin derivatives 3 and 5a–o was designed and synthesised. The CA inhibition activities for the synthesised coumarins were analysed on isoforms hCA I, II, IX, and XII. Interestingly, both cancer-linked isoforms hCA IX/XII were inhibited by the prepared coumarins with inhibition constants ranging from sub- to low-micromolar range, whereas hCA I and II isoforms haven’t been inhibited up to 100 µM. Furthermore, the target coumarins were assessed for their antitumor activity on NCI-59 human cancer types.

Continuous Flow Biocatalysis: Synthesis of Coumarin Carboxamide Derivatives by Lipase TL IM from Thermomyces lanuginosus

Coumarin carboxamide derivatives are important building blocks for organic synthesis and chemical biology due to their excellent biopharmaceutical properties. In this paper, we demonstrate for the first time a two-step enzymatic synthesis of coumarin carboxamide derivatives. Salicylaldehyde and dimethyl malonate were reacted to obtain coumarin carboxylate methyl derivatives, which were then reacted with various amines under the catalysis of lipase TL IM from Thermomyces lanuginosus to obtain coumarin carboxamide derivatives in continuous flow reactors. We studied various reaction parameters on the yields. The important features of this method include mild reaction conditions, a short reaction time (40 min), reduced environmental pollution, higher productivity (STY = 31.2941 g L−1 h−1) and enzymes being relatively easy to obtain.

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.

Recent Developments of Coumarin-based Hybrids in Drug Discovery

Coumarin scaffold is a highly significant O-heterocycle, namely benzopyran-2-ones, form an elite class of naturally occurring compounds that possess promising therapeutic perspectives. Based on its broad spectrum of biological activities, the privileged coumarin scaffold is applied to medicinal and pharmacological treatments by several rational design strategies and approaches. Structure-activity relationships of the coumarin-based hybrids with various bioactivity fragments revealed significant information toward the further development of highly potent and selective disorder therapeutic agents. The molecular docking studies between coumarins and critical therapeutic enzymes demonstrated mode of action by forming noncovalent interactions with more than one receptor, further rationally confirm information about structure-activity relationships. This review summarizes recent developments relating to coumarin-based hybrids with other pharmacophores aiming to numerous feasible therapeutic enzymatic targets to combat various therapeutic fields, including anticancer, antimicrobic, anti-Alzheimer, anti-inflammatory activities.

Design, synthesis and biological activity evaluation of novel scopoletin-NO donor derivatives against MCF-7 human breast cancer in vitro and in vivo

In this study, eleven new 3- and 7-positions modified scopoletin derivatives (18a-k) were designed, synthesized, and biologically evaluated against human breast cancer cell lines. Most compounds showed improved antiproliferative activity against MCF-7 and MDA-MB-231 cells and weaker cytotoxicity on human breast epithelial cell line MCF-10A than lead compound 5. Among them, compound 18e exhibited the most potent antiproliferative activity against MCF-7 cells (IC₅₀ = 0.37 ± 0.05 μM). Particularly, 18e produced the highest levels of nitric oxide (NO) intracellularly, and its antiproliferation effect was attenuated by hemoglobin (an NO scavenger). Further pharmacological research showed that 18e blocked the cell cycle at the G₂/M phase, downregulated the phosphorylation of PI3K and Akt in MCF-7 cells and regulated the expressions of the apoptosis proteins to induce apoptosis. Moreover, 18e inhibited the growth of MCF-7 in vivo. Overall, 18e is a novel anticancer agent with the abilities of high concentration of NO releasing and the inhibition of PI3K/Akt signaling pathway, and may be a promising agent against MCF-7 human breast cancer.

Synthesis and Biological Evaluation of Coumarin-Linked 4-Anilinomethyl-1,2,3-Triazoles as Potent Inhibitors of Carbonic Anhydrases IX and XIII Involved in Tumorigenesis

A series of coumarin-linked 4-anilinomethyl-1,2,3-triazoles (6a–t) was synthesized via a molecular hybridization approach, through carbon C-6 of the coumarin moiety. The synthesized compounds were evaluated for their inhibition of carbonic anhydrase (CA) isoforms I, II, IX and XIII. CAs IX and XIII were selectively inhibited over the off-target isoforms I and II. The best inhibitory profiles against CA IX were shown by compounds 6a, 6e and 6f (K_i < 50 nM), with compound 6e displaying the best inhibition with a K_i value of 36.3 nM. Compounds 6a, 6b, 6j, 6o and 6q exhibited the best inhibitory profiles against CA XIII (K_i < 100 nM). These compounds can be further explored for the discovery of potent and effective CA IX and CA XIII inhibitors.

Coumarin-Thiourea Hybrids Show Potent Carbonic Anhydrase IX and XIII Inhibitory Action

A series of coumarin-thiourea hybrids (4 a-o) has been synthesized, and the compounds have been evaluated against the tumour associated transmembrane isoform, human (h) carbonic anhydrase (CA) hCA IX and the less-explored cytosolic isoform, hCA XIII. All compounds exhibited potent inhibition of both isoforms, with K_I values of <100 nM against hCA IX. Compound 4 b was the best inhibitor (K_I =78.5 nM). All the compounds inhibited hCA XIII in the low-nanomolar to sub-micromolar range, with compound 4 b again showing the best inhibition (K_I =76.3 nM). With compound 4 b as a lead, more-selective inhibitors of hCA IX and hCA XIII or dual hCA IX/XIII inhibitors might be developed.

Synthesis and biological evaluation of some coumarin hybrids as selective carbonic anhydrase IX and XII inhibitors

Two series, coumarin-linked to thiazolidinone via a pyrazole linker (6a-m, Series 1) and coumarin-linked 1,2,3-triazoles (5a-j, Series 2) were synthesized and the synthesized compounds were subjected for evaluation against the four physiologically and pharmacologically relevant hCA isoforms, hCA I, II, IX and XII. The results indicated selective inhibition of tumor-associated isoforms hCA IX and XII over the off-target isoforms, hCA I and II. The compounds of series 1 exhibited better hCA IX inhibition compared to hCA XII, with compounds 6i, 6h, 6a and 6k, exhibiting notable K_i values of less than 100 nM. Among all the compounds, compound 6i showed the best inhibition with a K_i value of 61.5 nM. Among the compounds of series 2, compounds 5a, 5b, 5c, 5d, 5f and 5j exhibited notable hCA IX inhibition. Compound 5d showed the best inhibition with a K_i value of 32.7 nM. In the case of hCA XII, compound 5i showed the best inhibition with a K_i value of 84.2 nM. Hence, compound 6i from Series 1 and 5d from Series 2 could be taken as lead compounds for the further development of selective and potent hCA IX inhibitors, whereas the compound 5i from Series 2 can be explored further for the design of selective and potent hCA XII inhibitors.

New coumarin/sulfocoumarin linked phenylacrylamides as selective transmembrane carbonic anhydrase inhibitors: Synthesis and in-vitro biological evaluation

Two novel series of phenylacrylamide linked coumarins and sulfocoumarins (6a-p, 8a-i, and 14a-g) were synthesized and evaluated against four physiologically relevant human carbonic anhydrases (hCAs, EC 4.2.1.1), isoforms hCA I, hCA II, hCA IX and hCA XII for their inhibitory action. All new compounds when screened for carbonic anhydrase inhibitory activity have shown selective inhibition towards the tumor associated isoforms hCA IX and XII over CA I and II, with inhibition constants in the submicromolar to low nanomolar range. Compound 6b and 14g exhibited significant inhibition with low nanomolar potency against hCA IX, whereas 6k was effective against hCA XII. Compounds 6b, 14g and 6k may be considered as lead molecules for future development of cancer therapeutics based on a novel mechanism of action.

Design, synthesis and biological evaluation of coumarin linked 1,2,4-oxadiazoles as selective carbonic anhydrase IX and XII inhibitors

A series of coumarin linked 1,2,4-oxadiazoles were synthesized and the synthesized compounds were subjected for evaluation against the four physiologically and pharmacologically relevant hCA isoforms, hCA I, II, IX and XII. Upon evaluation of the results, it was inferred that the coumarin linked 1,2,4-oxadiazoles showed selective hCA IX and XII inhibition (low to medium nanomolar range) over hCA I and II (>10000 nM). The inhibition constants ranged from low nanomolar to moderately nanomolar. Compounds 6o, 6a, 6q and 6c elicited hCA XII inhibition, with K_i values lower than that of the standard, Acetazolamide (AAZ) with compound 6o exhibiting a K_i value of 1 nM., against hCA IX, the compound 6c exhibited the most potent inhibition with a K_i value of 23.6 nM. Hence, compound 6o can be taken as an effective lead compound for the development of hCA XII inhibitors and compound 6c can be taken as a lead compound for the development of dual hCA IX and XII inhibitors. To understand the molecular interactions, the two most potent compounds 6a and 6o were docked within the hCA XII catalytic cleft in order to study their binding modes with that isoform.

Design, Synthesis, and Molecular Modeling Studies of Novel Coumarin Carboxamide Derivatives as eEF-2K Inhibitors

Eukaryotic elongation factor-2 kinase (eEF-2K) is an unusual alpha kinase commonly upregulated in various human cancers, including breast, pancreatic, lung, and brain tumors. We have demonstrated that eEF-2K is relevant to poor prognosis and shorter patient survival in breast and lung cancers and validated it as a molecular target using genetic methods in related in vivo tumor models. Although several eEF-2K inhibitors have been published, none of them have shown to be potent and specific enough for translation into clinical trials. Therefore, development of highly effective novel inhibitors targeting eEF-2K is needed for clinical applications. However, currently, the crystal structure of eEF-2K is not known, limiting the efforts for designing novel inhibitor compounds. Therefore, using homology modeling of eEF-2K, we designed and synthesized novel coumarin-3-carboxamides including compounds A1, A2, and B1-B4 and evaluated their activity by performing in silico analysis and in vitro biological assays in breast cancer cells. The Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) area results showed that A1 and A2 have interaction energies with eEF-2K better than those of B1-B4 compounds. Our in vitro results indicated that compounds A1 and A2 were highly effective in inhibiting eEF-2K at 1.0 and 2.5 μM concentrations compared to compounds B1-B4, supporting the in silico findings. In conclusion, the results of this study suggest that our homology modeling along with in silico analysis may be effectively used to design inhibitors for eEF-2K. Our newly synthesized compounds A1 and A2 may be used as novel eEF-2K inhibitors with potential therapeutic applications.

Synthesis and biological evaluation of novel 8-substituted quinoline-2-carboxamides as carbonic anhydrase inhibitors

A series of novel 8-substituted-N-(4-sulfamoylphenyl)quinoline-2-carboxamides was synthesised by the reaction of 8-hydroxy-N-(4-sulfamoylphenyl) quinoline-2-carboxamide with alkyl and benzyl halides. The compounds were assayed for carbonic anhydrase (CA) inhibitory activity against four hCA isoforms, hCA I, hCA II, hCA IV, and hCA IX. Barring hCA IX, all the isoforms were inhibited from low to high nanomolar range. hCA I was inhibited in the range of 61.9–8126 nM, with compound 5h having an inhibition constant of K_I = 61.9 nM. hCA II was inhibited in the range of 33.0–8759 nM, with compound 5h having an inhibition constant of 33.0 nM and compounds 5a and 5b having inhibition constants of 88.4 and 85.7 nM, respectively. hCA IV was inhibited in the range of 657.2–6757 nM. Hence, compound 5h, possessing low nanomolar hCA I and II inhibition, can be selected as a lead for the design of novel CA I and II inhibitors.