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

Identification of Ureidocoumarin-Based Selective Discoidin Domain Receptor 1 (DDR1) Inhibitors via Drug Repurposing Approach, Biological Evaluation, and In Silico Studies

Discoidin domain receptor 1 (DDR1) kinase has emerged as a promising target for cancer therapy, and selective DDR1 inhibitors have shown promise as effective therapeutic candidates. Herein, we have identified the first coumarin-based selective DDR1 inhibitors via repurposing of a recent series of carbonic anhydrase inhibitors. Among these, ureidocoumarins 3a, 3i, and 3q showed the best DDR1 inhibitory activities. The m-trifluoromethoxy phenyl member 3q potently inhibited DDR1 with an IC50 of 191 nM, while it showed less inhibitory activity against DDR2 (IC50 = 5080 nM). 3q also exhibited favorable selectivity in a screening platform with 23 common off-target kinases, including BCR-ABL. In the cellular context, 3q showed moderate antiproliferative effects, while 3i, with the third rank in DDR1 inhibition, exerted the best anticancer activity with sub-micromolar GI50 values over certain DDR1-dependent cell lines. Molecular docking and MD simulations disclosed the putative binding mode of this coumarin chemotype and provided insights for further optimization of this scaffold. The present findings collectively supported the potential improvement of ureidocoumarins 3i and 3q for cancer treatment.

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.

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.

Discovery of new 6-ureido/amidocoumarins as highly potent and selective inhibitors for the tumour-relevant carbonic anhydrases IX and XII

A series of 6-ureido/amidocoumarins (5a-p and 7a-c) has been designed and synthesised to develop potent and isoform- selective carbonic anhydrase hCA XI and XII inhibitors. All coumarin derivatives were investigated for their CA inhibitory effect against hCA I, II, IX, and XII. Interestingly, target coumarins potently inhibited both tumour-related isoforms hCA IX (K_Is: 14.7-82.4 nM) and hCA XII (K_Is: 5.9-95.1 nM), whereas the cytosolic off-target hCA I and II isoforms have not inhibited by all tested coumarins up to 100 μM. These findings granted the target coumarins an excellent selectivity profile towards both hCA IX and hCA XII isoforms, supporting their development as promising anticancer candidates. Moreover, all target molecules were evaluated for their anticancer activities against HCT-116 and MCF-7 cancer cells. The 3,5-bis-trifluoromethylphenyl ureidocoumarin 5i, exerted the best anticancer activity. Overall, ureidocoumarins, particularly compound 5i, could serve as a promising prototype for the development of potent anticancer CAIs.

6-Aminocoumarin oxime-ether/sulfonamides as selective hCA IX and XII inhibitors: Synthesis, evaluation, and molecular dynamics studies

Carbonic anhydrase isoforms IX and XII are overexpressed in hypoxic tumor cells regulating various physiological processes such as cell proliferation, invasion, and metastasis, resulting in the onset and spread of cancer. Selective inhibition of these enzymes is a promising strategy for anticancer therapy. Coumarin derivatives were identified as selective and potent inhibitors of these isoforms. This study reports 6-aminocoumarin sulfonamide and oxime ether derivatives linked through a chloroacetyl moiety tethered to piperazine and piperidone, respectively, showing selective inhibition against human carbonic anhydrase (hCA) IX and XII with Ki ranging from 0.51 to 1.18 µM and 0.89-4.43 µM. While the sulfonamide derivative 8a exhibited submicromolar inhibition against hCA IX and XII with Ki 0.89 and 0.51 µM, the oxime ether derivatives showed lower activity than the sulfonamides, with the compound 5n inhibiting hCA IX and hCA XII with a Ki of 1.055 and 0.70 µM, respectively. The above results demonstrate the potential of these derivatives as selective, potent inhibitors of carbonic anhydrase IX and XII and provide a foundation for further optimization and development as effective anticancer agents. Further, the binding mode of the synthesized derivatives in the active site were examined using molecular docking and dynamic simulation studies.

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

A series of coumarin-linked thiazoles (6a-p) was synthesized and the synthesized compounds were evaluated against human carbonic anhydrases (hCAs) IX and XII, which have been implicated in cancer. All the compounds exhibited selective inhibition of both isoforms. The designed compounds inhibited hCA IX in a moderate nanomolar to submicromolar range. The hCA XII was inhibited in a low to moderate nanomolar range. Compound 6o exhibited the best inhibition of hCA XII with a K_i value of 91.1 nM. The hydrolyzed form of compound 6o also exhibited favorable interactions as well as good docking scores with both the isoforms. Hence, this compound can be taken as a template for the design of selective and potent hCA XII inhibitors.

Synthesis of a new series of quinoline/pyridine indole-3-sulfonamide hybrids as selective carbonic anhydrase IX inhibitors

In this manuscript, design, rational, synthesisand carbonic anhydrases (CAs) inhibitory profile of the quinoline/pyridine linked indole-3-sulfonamide derivatives were reported. The library of 29newly quinoline/pyridine indole-3-sulfonamide derivatives have been generated and examined against the panel of four physiological relevant human CA isoforms, namely, the cytosolic isoforms hCA I and hCA II and the transmembrane tumor associated isoforms hCA IX and hCA XII. Pyridine indole-3-sulfonamide hybrids are selective inhibit transmembrane tumor associated isoforms hCA IX and hCA XII. However, all synthesized quinoline indole-3-sulfonamide hybrids have inhibitory effect on hCA IX isoforms, whereas few have shown inhibitory activity against hCA II and hCA XII as well. However, among all synthesized compound 6q and6p having good inhibitory activity against hCA IX with K_i 1.47 µM and 1.57 µM respectively.These quinoline/pyridine indole-3-sulfonamide conjugatesmay be regarded as potential leads for hCA IXselective inhibitors as anti-cancer agents.

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.

Ureidosulfocoumarin Derivatives As Selective and Potent Carbonic Anhydrase IX and XII Inhibitors

Owing to severe allergic reactions (anaphylaxis) and resistance exhibited by sulfonamide-based carbonic anhydrase (CA) inhibitors, non-classical or non-sulfonamide CA inhibitors are gaining increased attention by medicinal chemists. In this context, we report the design and synthesis of 30 new non-sulfonamide sulfocoumarin derivatives as CA inhibitors. They were investigated against hCA I and II (cytosolic isozymes) as well as hCA IX and XII (transmembrane, tumor-associated enzymes). All compounds showed prominent selectivity for the tumor-associated isoenzymes hCA IX and XII over the cytosolic isoenzymes hCA I and II. Among all synthesized compounds, 1-(2,2-dioxidobenzo[e][1,2]oxathiin-6-yl)-3-(o-tolyl)urea(5 j)and1-(3-fluorophenyl)-3-(8-methoxy-2,2-dioxidobenzo[e][1,2]oxathiin-6-yl)urea(5 q)were found to be more potent and to have better inhibition constant values against hCA IX than the standard acetazolamide (AAZ), with K_i values of 23.6 and 23.3 nM, respectively. All other compounds were found to be active under K_i =920 nM against hCA IX and XII.This study provides a new perspective for the future development of non-sulfonamide derivatives as selective CA inhibitors.

Design and development of novel series of indole-3-sulfonamide ureido derivatives as selective carbonic anhydrase II inhibitors

Indole is a privileged moiety with a wide range of bioactivities, making it a popular scaffold in drug design and development studies as well as in synthetic chemistry. Here, novel urea derivatives of indole, containing sulfonamide at position-3 of indole, were synthesized using a well-known tail approach, as carbonic anhydrases (CAs; EC 4.2.1.1) inhibitors. All the newly synthesized molecules were screened for their CA-inhibitory activity against four clinically relevant isoforms of human-origin carbonic anhydrase (hCA), that is, hCA I, hCA II, hCA IX, and hCA XII. These compounds were specifically active against hCA II, more than against hCA I, hCA IX, and hCA XII. Derivative 6l was found to be most active, with a K_i value of 7.7 µM against hCA II.