Novel 4/3-((4-oxo-5-(2-oxoindolin-3-ylidene)thiazolidin-2-ylidene)amino) benzenesulfonamides: Synthesis, carbonic anhydrase inhibitory activity, anticancer activity and molecular modelling studies

Design and synthesis of novel pyrazolo[3,4-d]pyrimidin-4-one bearing quinoline scaffold as potent dual PDE5 inhibitors and apoptotic inducers for cancer therapy

PDE5 targeting represents a new and promising strategy for apoptosis induction and inhibition of tumor cell growth due to its over-expression in diverse types of human carcinomas. Accordingly, we report the synthesis of series of pyrazolo[3,4-d]pyrimidin-4-one carrying quinoline moiety (11a-r) with potential dual PDE5 inhibition and apoptotic induction for cancer treatment. These hybrids were structurally elucidated and characterized with variant spectroscopic techniques as ¹H NMR, ¹³C NMR and elemental analysis. The assessment of their anticancer activities has been declared. All the rationalized compounds 11a-r have been selected for their cytotoxic activity screening by NCI against 60 cell lines. Compounds 11a, 11b, 11j and 11k were the most active hybrids. Among all, compound 11j was further selected for five dose tesing and it displayed outstanding activity with strong antitumor activity against the nine tumor subpanels tested with selectivity ratios ranging from 0.019 to 8.3 at the GI₅₀ level. Further, the most active targets 11a, b, j and k were screened for their PDE5 inhibitory activity, compound 11j (with IC₅₀ 1.57 nM) exhibited the most potent PDE5 inhibitory activity. Moreover, compound 11j is also showed moderate EGFR inhibition with IC₅₀ of 5.827 ± 0.46 µM, but significantly inhibited the Wnt/β-catenin pathway with IC₅₀1286.96 ± 12.37 ng/mL. In addition, compound 11j induced the intrinsic apoptotic mitochondrial pathway in HepG2 cells as evidenced by the lower expression levels of the anti-apoptotic Bcl-2 protein, and the higher expression of the pro-apoptotic protein Bax, p53, cytochrome c and the up-regulated active caspase-9 and caspase-3 levels. All results confirmed by western blotting assay. Compound 11j exhibit pre G1 apoptosis and cell cycle arrest at G2/M phase. In conclusion, hybridization of quinoline moiety with the privileged pyrazolo[3,4-d]pyrimidinon-4-one structure resulted in highly potent anticancer agent, 11j, which deserves more study, in particular, in vivo and clinical investiagtions, and it is expected that these results would be applied for more drug discovery process.

Discovery of new pyrimidine-5-carbonitrile derivatives as anticancer agents targeting EGFRWT and EGFRT790M

A new series of pyrimidine-5-carbonitrile derivatives has been designed as ATP mimicking tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR). These compounds were synthesized and evaluated for their in vitro cytotoxic activities against a panel of four human tumor cell lines, namely colorectal carcinoma (HCT-116), hepatocellular carcinoma (HepG-2), breast cancer (MCF-7), and non-small cell lung cancer cells (A549). Five of the synthesized compounds, 11a, 11b, 12b, 15b and 16a, were found to exhibit moderate antiproliferative activity against the tested cell lines and were more active than the EGFR inhibitor erlotinib. In particular, compound 11b showed 4.5- to 8.4-fold erlotinib activity against HCT-116, HepG-2, MCF-7, and A549 cells with IC50 values of 3.37, 3.04, 4.14, and 2.4 μM respectively. Moreover, the most cytotoxic compounds that showed promising IC50 values against the four cancer cell lines were subjected to further investigation for their kinase inhibitory activities against EGFRWT and EGFRT790M using homogeneous time resolved fluorescence (HTRF) assay. Compound 11b was also found to be the most active compound against both EGFRWT and mutant EGFRT790M, exhibiting IC50 values of 0.09 and 4.03 μM, respectively. The cell cycle and apoptosis analyses revealed that compound 11b can arrest the cell cycle at the G2/M phase and induce significant apoptotic effects in HCT-116, HepG-2, and MCF-7 cells. Additionally, compound 11b upregulated the level of caspase-3 by 6.5 fold in HepG-2 when compared with the control. Finally, molecular docking studies were carried out to examine the binding mode of the synthesized compounds against the proposed targets; EGFRWT and EGFRT790M. Additional in silico ADMET studies were performed to explore drug-likeness properties.

A Series of Isatin-Hydrazones with Cytotoxic Activity and CDK2 Kinase Inhibitory Activity: A Potential Type II ATP Competitive Inhibitor

Isatin derivatives potentially act on various biological targets. In this article, a series of novel isatin-hydrazones were synthesized in excellent yields. Their cytotoxicity was tested against human breast adenocarcinoma (MCF7) and human ovary adenocarcinoma (A2780) cell lines using MTT assay. Compounds 4j (IC50 = 1.51 ± 0.09 µM) and 4k (IC50 = 3.56 ± 0.31) showed excellent activity against MCF7, whereas compound 4e showed considerable cytotoxicity against both tested cell lines, MCF7 (IC50 = 5.46 ± 0.71 µM) and A2780 (IC50 = 18.96± 2.52 µM), respectively. Structure-activity relationships (SARs) revealed that, halogen substituents at 2,6-position of the C-ring of isatin-hydrazones are the most potent derivatives. In-silico absorption, distribution, metabolism and excretion (ADME) results demonstrated recommended drug likeness properties. Compounds 4j (IC50 = 0.245 µM) and 4k (IC50 = 0.300 µM) exhibited good inhibitory activity against the cell cycle regulator CDK2 protein kinase compared to imatinib (IC50 = 0.131 µM). A molecular docking study of 4j and 4k confirmed both compounds as type II ATP competitive inhibitors that made interactions with ATP binding pocket residues, as well as lacking interactions with active state DFG motif residues.

Densely functionalized cinnolines: Controlled microwave-assisted facile one-pot multi-component synthesis and in vitro anticancer activity via apoptosis induction

There is an urging continuous need for novel anti-cancer agents due to persistent chemoresistance. Herein, newly synthesized cinnolines are evaluated for their possible anticancer activities and suggested mechanisms. In the current study, a simple and efficient synthesis of densely functionalized cinnolines has been developed that relied on multi-component reaction of ethyl 5-cyano-4-methyl-1-aryl-6-oxo-1,6-dihydropyridazine-3-carboxylates with aromatic aldehydes and nitromethane in dioxane/pipridine under controlled microwave heating. Selected cinnolines (4a-c, e, h, j-n, q-v) were tested for possible anticancer activity using in vitro one dose assay at National Cancer institute, USA. Only cinnoline 4b stood out as the most potent cinnoline derivative (mean GI%=26.33) with broad-spectrum antitumor activity against the most tested cancer cell lines from all subpanels. The target cinnoline 4b emerged as the most active derivative against both leukemia RPMI-8226 and melanoma LOX IMVI cell lines (GI% = 106.06 and 82.1) respectively, with IC₅₀ values equal to 17.12 ± 1.31 and 12.32 ± 0.75 μg/mL, which are comparable to those of staurosporin; 24.97 ± 1.47 and 8.45 ± 0.42 μg/mL, respectively. Cinnoline 4b influenced cell cycle distribution causing pre-G1 apoptosis and cell growth arrest at G2/M phase. It also induced apoptosis in both cell lines as manifested by significant increase in the percent of annexin V-FITC positive apoptotic cells in leukemia RPMI-8226 cells (from 1.09% to 12.47%) and melanoma LOX IMVI (from 1.32% to 19.05%). In addition, it showed lower expression levels of anti-apoptotic Bcl-2 protein, and higher expression levels of pro-apoptotic proteins; Bax, p53, cytochrome c, caspases 3 and 9. CONCLUSION: Induction of mitochondrial intrinsic pathway of apoptosis is a possible mechanism by which cinnoline 4b may confer its anticancer activity.

Screening of Some Sulfonamide and Sulfonylurea Derivatives as Anti-Alzheimer’s Agents Targeting BACE1 and PPARγ

In the last few decades, Alzheimer’s disease (AD) has emerged as a serious global problem, and it has been considered as the most common type of dementia. PPARγ and beta-secretase 1 (BACE1) are considered as potential targets for Alzheimer’s disease management. In the same time, sulfonylureas and sulfonamides have been confirmed to have PPARγ agonistic activity. Aiming to obtain new anti-AD agents, thirty-five compounds of sulfonamide and sulfonylurea derivatives having the same essential pharmacophoric features of the reported PPARγ agonists have been subjected to virtual screening. Docking studies revealed that five compounds (1, 2, 3, 4, and 5) have promising affinities to PPARγ. They were also docked into the binding site of BACE1. In addition, ADMET and physicochemical properties of these compounds were considered. Additionally, these compounds were further evaluated against BACE1 and PPARγ. Compound 2 showed IC50 value of 1.64 μM against BACE1 and EC50 value of 0.289 μM against PPARγ.

One-Pot Synthesis of Novel Thiazoles as Potential Anti-Cancer Agents

BACKGROUND

Thiazole and thiosemicarbazone derivatives are known to have potential anticancer activity with a mechanism of action related to inhibition of matrix metallo-proteinases, kinases and anti-apoptotic BCL2 family proteins.

MATERIALS AND METHODS

A novel three series of 5-(1-(2-(thiazol-2-yl)hydrazono)ethyl)thiazole derivatives were prepared in a one-pot three-component reaction using 2-(2-benzylidene hydrazinyl)-4-methylthiazole as a starting precursor. MS, IR, 1H-NMR and 13C-NMR were used to elucidate the structures of the synthesized compounds. Most of the synthesized products were evaluated for their in vitro anticancer screening against HCT-116, HT-29 and HepG2 using the MTT colorimetric assay.

RESULTS

The results indicated that compounds 4c, 4d and 8c showed growth inhibition activity against HCT-116 with IC50 values of 3.80 ± 0.80, 3.65 ± 0.90 and 3.16 ± 0.90 μM, respectively, compared to harmine (IC50 = 2.40 ± 0.12 μM) and cisplatin (IC50 = 5.18 ± 0.94 μM) reference drugs. Also, compounds 8c, 4d and 4c showed promising IC50 values of 3.47 ± 0.79, 4.13 ± 0.51 and 7.24 ± 0.62 μM, respectively, against the more resistant human colorectal cancer (HT-29) cell line compared with harmine (IC50 = 4.59 ± 0.67 μM) and cisplatin (IC50 = 11.68 ± 1.54 μM). On the other hand, compounds 4d, 4c, 8c and 11c were the most active (IC50 values of 2.31± 0.43, 2.94 ± 0.62, 4.57 ± 0.85 and 9.86 ± 0.78 μM, respectively) against the hepatocellular carcinoma (HepG2) cell line compared with harmine (IC50 = 2.54 ± 0.82 μM) and cisplatin (IC50 = 41 ± 0.63 μM). The study also suggested that the mechanism of the anticancer action exerted by the most active compounds (4c, 4d and 8c) inside HCT-116 cells was apoptosis through the Bcl-2 family.

CONCLUSION

Thiazole scaffolds 4c, 4d and 8c showed anticancer activities in the micromolar range and are appropriate as a candidate for cancer treatment.

Discovery of Potent Dual-Tailed Benzenesulfonamide Inhibitors of Human Carbonic Anhydrases Implicated in Glaucoma and in Vivo Profiling of Their Intraocular Pressure-Lowering Action

The design of three dual-tailed sulfonamide series 11a-11g, 14a-14h, and 16a-16e as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors are presented. All compounds were evaluated for inhibitory action against pharmacologically relevant human CA isoforms I, II, IV, and VII. Compounds 11a-11g emerged as potent CA inhibitors against the four tested isoforms with a significant selectivity to CA II, which is implicated in glaucoma (K_i in the range 0.36-6.9 nM). X-ray crystallographic analysis of three compounds (11a, 11d, and 11g) bound to CA II showed the validity of the adopted drug design strategy as specific moieties within the ligand structure interacted directly with the hydrophobic and hydrophilic halves of the CA II active site. Compounds 11b-11d and 11g were evaluated for their intraocular pressure-lowering effects in a rabbit model of glaucoma. 11b and 11d showed significant efficacy when compared to the clinically used drug dorzolamide.

Recent advances in isatin hybrids as potential anticancer agents

The isatin framework is a useful template for the development of novel anticancer agents. This is exemplified by the fact that several isatin-based anticancer agents, such as semaxanib, sunitinib, nintedanib, and hesperadin, are already in use or under clinical trials for the treatment of diverse kinds of cancers. Isatin-based hybrids could be obtained by incorporating other anticancer pharmacophores into the isatin skeleton and they have the potential to overcome drug resistance with reduced side effects. Thus, isatin-based hybrids may provide attractive scaffolds for the development of novel anticancer agents. This review covers the recent advances of isatin-based hybrids with anticancer activity, covering articles published between 2001 and 2019. The anticancer activities of these molecules and the structure-activity relationships are also discussed. The purpose of this review article is to set up the direction for the design and development of isatin-based hybrids with high efficacy and low toxicity.

Design, eco-friendly synthesis, molecular modeling and anticancer evaluation of thiazol-5(4H)-ones as potential tubulin polymerization inhibitors targeting the colchicine binding site

In recent years, suppressing tubulin polymerization has been developed as a therapeutic approach for cancer treatment. Thus, new derivatives based on thiazol-5(4H)-ones have been designed and synthesized in an eco-friendly manner. The synthesized derivatives have the same essential pharmacophoric features of colchicine binding site inhibitors. The anti-proliferative activity of the new derivatives was evaluated on three human cancer cell lines (HCT-116, HepG-2, and MCF-7) using MTT assay procedure and colchicine was used as a positive control. Compounds 4f, 5a, 8f, 8g, and 8k showed superior antiproliferative activities against the three tested cell lines with IC50 values ranging from 2.89 to 9.29 μM. Further investigation for the most active cytotoxic agents as tubulin polymerization inhibitors was also performed in order to explore the mechanism of their anti-proliferative activity. Tubulin polymerization assay results were found to be comperable with the cytotoxicity results. Compounds 4f and 5a were the most potent tubulin polymerization inhibitors with an IC50 value of 9.33 and 9.52 nM, respectively. Further studies revealed the ability of 5a to induce apoptosis and arrest cell cycle growth at the G2/M phase. Molecular docking studies were also conducted to investigate possible binding interactions between the target compounds and the tubulin heterodimer active site. From these studies, it was concluded that inhibition of tubulin polymerization yields the reported cytotoxic activity.

3-Hydrazinoisatin-based benzenesulfonamides as novel carbonic anhydrase inhibitors endowed with anticancer activity: Synthesis, in vitro biological evaluation and in silico insights

Herein we describe the design and synthesis of two series of sulfonamides featuring N-unsubstituted (4a-c) or N-substituted (7a-o) isatin moieties (as tails) connected to benzenesulfonamide moiety via a hydrazine linker. All the prepared sulfonamides (4a-c and 7a-o) showed potent inhibitory activities toward transmembrane tumor-associated human (h) carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, IX and XII with KI range (8.3-65.4 nM) and (11.9-72.9 nM), respectively. Furthermore, six sulfonamides (7e, 7i, 7j, 7m, 7n and 7o) were assessed for their anti-proliferative activity, according to US-NCI protocol, toward a panel of sixty cancer cell lines. Compounds 7j and 7n were the most promising counterparts in this assay displaying broad spectrum anti-proliferative activity toward diverse cell lines. Also, sulfonamide 7n significantly inhibited clonogenicity of HCT-116 cells in a concentration dependent manner in the colony forming assay. Moreover, molecular modeling studies were performed to gain insights for the plausible binding interactions and affinities for the target isatin-based sulfonamides (4a-c and 7a-o) within hCA isoforms II and IX active sites.

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 and in vitro anticancer activity of certain novel 1-(2-methyl-6-arylpyridin-3-yl)-3-phenylureas as apoptosis-inducing agents

In connection with our research program on the development of novel anticancer candidates, herein we report the design and synthesis of novel series of 1-(2-methyl-6-arylpyridin-3-yl)-3-phenylureas 5a-l. The target pyridins were evaluated for their in vitro anticancer activity against two cancer cell lines: non-small cell lung cancer A549 cell line and colon cancer HCT-116 cell line. Compound 5l emerged as the most active congener towards both A549 and HCT-116 cell lines with IC50 values equal to 3.22 ± 0.2 and 2.71 ± 0.16 µM, respectively, which are comparable to those of Doxorubicin; 2.93 ± 0.28 and 3.10 ± 0.22, respectively. Furthermore, compound 5l stood out as the most potent pyridine derivative (mean % GI = 40), at US-NCI Developmental Therapeutic Program anticancer assay, with broad-spectrum antitumor activity against the most tested cancer cell lines from all subpanels. Compound 5l was able to provoke apoptosis in HCT-116 cells as evidenced by the decreased expression of the anti-apoptotic Bcl-2 protein, and the enhanced expression of the pro-apoptotic proteins levels; Bax, cytochrome C, p53, caspase-3 and caspase-9. Moreover, 5l disrupted the HCT-116 cell cycle via alteration of the Sub-G1 phase and arresting the G2-M stage. Also, 5l showed a significant increase in the percent of annexinV-FITC positive apoptotic cells from 1.99 to 15.76%.

Synthesis, biological evaluation and in silico studies with 4-benzylidene-2-phenyl-5(4H)-imidazolone-based benzenesulfonamides as novel selective carbonic anhydrase IX inhibitors endowed with anticancer activity

In the presented work, we report the synthesis of a series of 4-benzylidene-2-phenyl-5(4H)-imidazolone-based benzenesulfonamides 7a-fvia the Erlenmeyer-Plöchl reaction. All the prepared imidazolones 7a-f were evaluated as inhibitors of human (h) carbonic anhydrases (CA, EC 4.2.1.1) cytosolic isoforms hCA I and II, as well as transmembrane tumor-associated isoforms hCA IX and XII. All the tested hCA isoforms were inhibited by the prepared imidazolones 7a-f in variable degrees with the following KIs ranges: 673.2-8169 nM for hCA I, 61.2-592.1 nM for hCA II, 23-155.4 nM for hCA XI, and 21.8-179.6 nM for hCA XII. In particular, imidazolones 7a, 7e, and 7f exhibited good selectivity towards the tumor-associated isoforms (CAs IX and XII) over the off-target cytosolic (CAs I and II) with selectivity index (SI) in the range of 6.2-19.4 and 3.3-8, respectively. Moreover, imidazolones 7a-f were screened for their anticancer activity in one dose (10-5 M) assay against a panel of 60 cancer cell lines according to US-NCI protocol. Furthermore, 7a, 7e and 7f were evaluated for their anti-proliferative activity against colorectal cancer HCT-116 and breast cancer MCF-7 cell lines. Furthermore, 7e and 7f were screened for cell cycle disturbance and apoptosis induction in HCT-116 cells. Finally, a molecular docking study was carried out to rationalize the obtained results.

Discovery and antiproliferative evaluation of new quinoxalines as potential DNA intercalators and topoisomerase II inhibitors

In continuation of our previous work on the design and synthesis of topoisomerase II (Topo II) inhibitors and DNA intercalators, a new series of quinoxaline derivatives were designed and synthesized. The synthesized compounds were evaluated for their cytotoxic activities against a panel of three cancer cell lines (Hep G-2, Hep-2, and Caco-2). Compounds 18b, 19b, 23, 25b, and 26 showed strong potencies against all tested cell lines with IC₅₀ values ranging from 0.26 ± 0.1 to 2.91 ± 0.1 µM, comparable with those of doxorubicin (IC₅₀ values ranging from 0.65 ± 0.1 to 0.81 ± 0.1 µM). The most active compounds were further evaluated for their Topo II inhibitory activities and DNA intercalating affinities. Compounds 19b and 19c exhibited high activities against Topo II (IC₅₀ = 0.97 ± 0.1 and 1.10 ± 0.1 µM, respectively) and bound the DNA at concentrations of 43.51 ± 2.0 and 49.11 ± 1.8 µM, respectively, whereas compound 28b exhibited a significant affinity to bind the DNA with an IC₅₀ value of 37.06 ± 1.8 µM. Moreover, apoptosis and cell-cycle tests of the most promising compound 19b were carried out. It was found that 19b can significantly induce apoptosis in Hep G-2 cells. It has revealed cell-cycle arrest at the G2/M phase. Moreover, compound 19b downregulated the Bcl-2 levels, indicating its potential to enhance apoptosis. Furthermore, molecular docking studies were carried out against the DNA-Topo II complex to examine the binding patterns of the synthesized compounds.

Anticancer sulfonamide hybrids that inhibit bladder cancer cells growth and migration as tubulin polymerisation inhibitors

Novel sulfonamide-dithiocarbamate hybrids were designed and synthesised via the molecular hybridisation strategy. Among them, compound 13d displayed a potent activity with IC₅₀ values of 0.9, 0.7, 1.9 and 2.6 µM against UM-UC-3, RT-112, RT4 and T24. Compound 13d inhibited the migration and regulated the migration-related markers (E-cadherin, N-cadherin, Vimentin, Snail and Slung) against RT-112 cells in a concentration dependent manner. By the tubulin polymerisation assay in vitro and immunostaining assay, compound 13d was identified as a novel tubulin polymerisation inhibitor. Intragastric administration of compound 13d could inhibit the growth of RT-112 cells in vivo in a xenograft mouse model with the low toxicity, indicating that it may be a leading candidate with antitumor properties to treat bladder cancer.

Design, synthesis, molecular modeling and anti-hyperglycemic evaluation of phthalimide-sulfonylurea hybrids as PPARγ and SUR agonists

New series of phthalimide-sulfonylurea hybrids were prepared and examined for their in vivo anti-hyperglycemic activities in STZ-induced hyperglycemic rats using glibenclamide as a reference drug. Compounds 6_c, 6_d, 6_g, 6_h, 6_j and 6_k induced significant reduction in the blood glucose levels of diabetic rats ranging from 24.43 to 21.43%. Moreover, molecular docking and pharmacophore approaches were carried out to examine binding modes and fit values of the prepared compounds against PPARγ and SUR, respectively. Compounds 6_c, 6_d, 6_j and 6_m exhibited the highest binding free energies against PPARγ. Compounds 6_c, 6_j, 6_k, 6_l, and 6_n showed the highest fit values against the generated pharmacophore model. Also, QSAR technique was carried out to estimate the proposed PPARγ binding affinities and insulin-secreting abilities. The synthesized compounds showed promising estimated activities. In-silico ADMET studies were performed to investigate pharmacokinetics of the synthesized compounds. They showed considerable human intestinal absorption with low BBB penetration.

Novel Diamide-Based Benzenesulfonamides as Selective Carbonic Anhydrase IX Inhibitors Endowed with Antitumor Activity: Synthesis, Biological Evaluation and In Silico Insights

In this work, we present the synthesis and biological evaluation of novel series of diamide-based benzenesulfonamides 5a–h as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms hCA I, II, IX and XII. The target tumor-associated isoforms hCA IX and XII were undeniably the most affected ones (K_Is: 8.3–123.3 and 9.8–134.5 nM, respectively). Notably, diamides 5a and 5h stood out as a single-digit nanomolar hCA IX inhibitors (K_Is = 8.8 and 8.3 nM). The SAR outcomes highlighted that bioisosteric replacement of the benzylidene moiety, compounds 5a–g, with the hetero 2-furylidene moiety, compound 5h, achieved the best IX/I and IX/II selectivity herein reported with SIs of 985 and 13.8, respectively. Molecular docking simulations of the prepared diamides within CA IX active site revealed the ability of 5h to establish an additional H-bond between the heterocyclic oxygen and HE/Gln67. Moreover, benzenesulfonamides 5a, 5b and 5h were evaluated for their antitumor activity against renal cancer UO-31 cell line. Compound 5h was the most potent derivative with about 1.5-fold more enhanced activity (IC₅₀ = 4.89 ± 0.22 μM) than the reference drug Staurosporine (IC₅₀ = 7.25 ± 0.43 μM). Moreover, 5a and 5h were able to induce apoptosis in UO-31 cells as evidenced by the significant increase in the percent of annexinV-FITC positive apoptotic cells by 22.5- and 26.5-folds, respectively.

Design, synthesis and anticancer evaluation of thieno[2,3-d]pyrimidine derivatives as dual EGFR/HER2 inhibitors and apoptosis inducers

Deregulation of many kinases is directly linked to cancer development and the tyrosine kinase family is one of the most important targets in current cancer therapy regimens. In this study, we have designed and synthesized a series of thieno[2,3-d]pyrimidine derivatives as an EGFR and HER2 tyrosine kinase inhibitors. All the synthesized compounds were evaluated in vitro for their inhibitory activities against EGFR^WT; and the most active compounds that showed promising IC₅₀ values against EGFR^WT were tested in vitro for their inhibitory activities against mutant EGFR^T790M and HER2 kinases. Moreover, the antitumor activities of these compounds were tested against four cancer cell lines (HepG2, HCT-116, MCF-7 and A431). Compounds 13g, 13h and 13k exhibited the highest activities against the examined cell lines with IC₅₀ values ranging from 7.592 ± 0.32 to 16.006 ± 0.58 µM comparable to that of erlotinib (IC₅₀ ranging from 4.99 ± 0.09 to 13.914 ± 0.36 µM). Furthermore, the most potent antitumor agent (13k) was selected for further studies to determine its effect on the cell cycle progression and apoptosis in MCF-7 cell line. The results indicated that this compound arrests G₂/M phase of the cell cycle and it is a good apoptotic agent. Finally, molecular docking studies showed a good binding pattern of the synthesized compounds with the prospective target, EGFR^WT and EGFR^T790M.

Novel synthesized SLC-0111 thiazole and thiadiazole analogues: Determination of their carbonic anhydrase inhibitory activity and molecular modeling studies

In the presented work, we report the design and synthesis of novel SLC-0111 thiazole and thiadiazole analogues (11a-d, 12a-d, 16a-c and 17a-d). A bioisosteric replacement approach was adopted to replace the 4-fluorophenyl tail of SLC-0111 with thiazole and thiadiazole ones, which were thereafter extended with lipophilic un/substituted phenyl moieties. All the newly synthesized SLC-0111 analogues were evaluated in vitro for their inhibitory activity towards a panel of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms (hCA I, II, IX and XII), using a stopped-flow CO₂ hydrase assay. All the examined isoforms were inhibited by the primary sulfonamide derivatives (11a-d and 12a-d) in variable degrees with the following K_I ranges: 162.6-7136 nM for hCA I, 9.0-833.6 nM for hCA II, 7.9-153.0 nM for hCA IX, and 9.4-94.0 nM for hCA XII. In particular, compounds 12b and 12d displayed 5.5-fold more potent inhibitory activity (K_Is = 8.3 and 7.9 nM, respectively) than SLC-0111 (K_I = 45 nM) towards hCA IX. Molecular docking study was carried out for 12d within the hCA IX (PDB 3IAI) active site, to justify its inhibitory activity.

Isatin and its derivatives: a survey of recent syntheses, reactions, and applications

Isatin (1H-indole-2,3-dione) and its derivatives represent an important class of heterocyclic compounds that can be used as precursors for drug synthesis. Since its discovery, a lot of research work has been done regarding the synthesis, chemical properties, and biological and industrial applications of isatin. In this review, we have reported several novel methods for the synthesis of N-, C2-, and C3-substituted and spiro derivatives of isatin. The isatin moiety also shows important chemical reactions such as oxidation, ring expansion, Friedel-Crafts reaction and aldol condensation. These reactions, in turn, produce several biologically viable compounds like 2-oxindoles, tryptanthrin, indirubins, and many more. We have also summarized some recently reported biological activities exhibited by isatin derivatives, like anti-cancer, anti-bacterial, anti-diabetic and others. Special attention has been paid to their anti-cancer activity, and various anti-cancer targets such as histone deacetylase, carbonic anhydrase, tyrosine kinase, and tubulin have been discussed in detail. Other applications of isatin derivatives, such as in the dye industry and in corrosion prevention, have also been discussed.

Novel 2-indolinones containing a sulfonamide moiety as selective inhibitors of candida β-carbonic anhydrase enzyme

Inhibition of the β-carbonic anhydrase (CA, EC 4.2.1.1) from pathogenic Candida glabrata (CgNce103) by 1H-indole-2,3-dione 3-[N-(4-sulfamoylphenyl)thiosemicarbazones] 4a–m was investigated. All the compounds were found to be potent inhibitors of CgNce103, with inhibition constants in the range of 6.4-63.9 nM. The 5,7-dichloro substituted derivative 4l showed the most effective inhibition (K_I of 6.4 nM) as well as the highest selectivity for inhibiting CgNce103 over the cytosolic human (h) isoforms hCA I and II. A possible binding interaction of compound 4l within the active site of CgNce103 has been proposed based on docking studies.

Inhibition studies on a panel of human carbonic anhydrases with N1-substituted secondary sulfonamides incorporating thiazolinone or imidazolone-indole tails

Being the primary sulfonamide among the most efficient zinc binding group (ZBG) to design inhibitors for the metallo-enzymes carbonic anhydrases (CA, EC 4.2.1.1), herein, we propose an investigation on four physiologically important human (h) CAs (hCA I, II, IV, and IX) with N1-substituted secondary sulfonamides incorporating thiazolinone or imidazolone-indole tails. The effect of the functionalisation of the sulfonamide group with five different substitution patterns, namely acetyl, pyridine, thiazole, pyrimidine, and carbamimidoyl, was evaluated in relation to the inhibition profile of the corresponding primary sulfonamide analogues. With most of these latter being nanomolar inhibitors of all four considered isoforms, a totally counterproductive effect on the inhibition potency can be ascribed to N1-functionalisations of the ZBG primary sulfonamide structure with pyridine, thiazole, and pyrimidine moieties. On the other hand, incorporation of less hindered groups, such as sulfonylacetamides and sulfonylguanidines, maintained a certain degree of activity dependent on the tailing moiety, with KIs spanning in the low micromolar range.

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.

SLC-0111 enaminone analogs, 3/4-(3-aryl-3-oxopropenyl) aminobenzenesulfonamides, as novel selective subnanomolar inhibitors of the tumor-associated carbonic anhydrase isoform IX

SLC-0111, an ureido substituted benzenesulfonamide, is a selective carbonic anhydrase (CA, EC 4.2.1.1) IX inhibitor that is currently in Phase I/II clinical trials for the treatment of advanced hypoxic tumors complicated with metastases. Herein we report the synthesis of two series of 3/4-(3-aryl-3-oxopropenyl) aminobenzenesulfonamides 5a-i and 6a-j as SLC-0111 enaminone congeners. The prepared enaminones were in vitro investigated as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms hCA I, II, IV and IX, using a stopped-flow CO₂ hydrase assay. All these isoforms were inhibited by the enaminones reported here in variable degrees. The target tumor-associated isoform hCA IX was undeniably the most affected one (K_Is: 0.21-7.1 nM), with 6- to 21-fold enhanced activity than SLC-0111 (K_I = 45 nM). All the prepared enaminones displayed interesting selectivity towards hCA IX over hCA I (SI: 32 - >35714), hCA II (SI: 2 - 1689) and hCA IV (SI: 11 - >45454). Of particular interest, bioisosteric replacement of phenyl tail with the bulkier 2-naphthyl tail, sulfonamide 6h, achieved the higher II/IX selectivity herein reported with SI of 1689.

Enhancement of the tail hydrophobic interactions within the carbonic anhydrase IX active site via structural extension: Design and synthesis of novel N-substituted isatins-SLC-0111 hybrids as carbonic anhydrase inhibitors and antitumor agents

Herein we report the design and synthesis of novel N-substituted isatins-SLC-0111 hybrids (6a-f and 9a-l). A structural extension approach was adopted via N-alkylation and N-benzylation of isatin moiety to enhance the tail hydrophobic interactions within the carbonic anhydrase (CA) IX active site. Thereafter, a hybrid pharmacophore approach was utilized via merging the pharmacophoric elements of isatin and SLC-0111 in a single chemical framework. As planned, a substantial improvement of inhibitory profile of the target hybrids (K_Is: 4.7-86.1 nM) towards hCA IX in comparison to N-unsubstituted leads IVa-c (K_Is: 192-239 nM), was achieved. Molecular docking of the designed hybrids in CA IX active site unveiled, as planned, the ability of N-alkylated and N-benzylated isatin moieties to accommodate in a wide hydrophobic pocket formed by T73, P75, P76, L91, L123 and A128, establishing strong van der Waals interactions. Hybrid 6c displayed good anti-proliferative activity under hypoxic conditions towards breast cancer MDA-MB-231 and MCF-7 cell lines (IC₅₀ = 7.43 ± 0.28 and 12.90 ± 0.34 μM, respectively). Also, 6c disrupted the MDA-MB-231 cell cycle via alteration of the Sub-G₁ phase and arrest of G₂-M stage. Additionally, 6c displayed significant increase in the percent of annexinV-FITC positive apoptotic cells from 1.03 to 18.54%. Furthermore, 6c displayed potent VEGFR-2 inhibitory activity (IC₅₀ = 260.64 nM). Collectively, these data suggest 6c as a promising lead molecule for the development of effective anticancer agents.

4-Substituted benzenesulfonamides featuring cyclic imides moieties exhibit potent and isoform-selective carbonic anhydrase II/IX inhibition

The synthesis, characterization and biological evaluation of series of cyclic imides incorporating the 4-sulfamoylbenzamide scaffold (16-29) is disclosed. The compounds were designed by application of the "tail approach" to the aromatic sulfonamide scaffold and prepared by reacting the proper acid anhydride with 4-(hydrazinecarbonyl)benzenesulfonamide (15). Phtalimides and cyclic imides are biologically privileged scaffolds, endowed with versatile biological activity, such as an anti-proliferative action. The compounds were investigated for the inhibition of four human (h) isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), and more specifically against the cytosolic hCA I and II and the transmembrane hCA IV and IX. Most screened sulfonamides exhibited great potency in inhibiting CA isoforms II, widely involved in glaucoma and other pathologies (K_Is in the range of 0.7-62.3 nM), and IX, that is a validated anti-tumor target (K_Is in the range of 3.0-50.9 nM), whereas interesting hydrophilicity-dependent inhibitory profiles were measured against isoform CA IV (K_Is in the range of 3.9-428.6 nM). In silico studies were carried out to assess the binding mode of selected derivatives to hCA II, IV and IX.

Synthesis of novel isoindoline-1,3-dione-based oximes and benzenesulfonamide hydrazones as selective inhibitors of the tumor-associated carbonic anhydrase IX

The synthesis, characterization and biological evaluation of a library of isoindoline-1,3-dione-based oximes and benzenesulfonamide hydrazones is disclosed. The set of hydroxyiminoethyl aromatic derivatives 10-18 was designed to assess the potentiality as zinc-binder for a feebly studied functional group in the field of carbonic anhydrase (CA, EC 4.2.1.1) inhibition. Analogue phenylphthalimmides were linked to benzenesulfonamide scaffold by hydrazone spacers in the second subset of derivatives 20-28 to further investigate the application of the "tail approach" as tool to afford CA selective inhibition profiles. The compounds were assayed for the inhibition of physiologically relevant isoforms of human carbonic anhydrases (hCA, EC 4.2.1.1), the cytosolic CA I and II, and the membrane-bound CA IV and tumor-associated CA IX. The new zinc-binders, both of the oxime and sulfonamide types, showed a striking selective activity against the target hCA IX over ubiquitous hCA I and II, with diverse inhibitory ranges and ratio differing the two subsets. With CA IX being a strongly current antitumor/antimetastatic drug target, these series of compounds may be of interest for the development of new, both conventional and unconventional anticancer drugs targeting hypoxia-induced CA isoforms such as CA IX with minimum ubiquitous CAs-related side effects.

Novel hydrazido benzenesulfonamides-isatin conjugates: Synthesis, carbonic anhydrase inhibitory activity and molecular modeling studies

As a part of our ongoing efforts towards developing novel carbonic anhydrase inhibitors based on the isatin moiety, herein we report the synthesis and biological evaluation of novel sulfonamides (5a-h, 10a-g and 11a-c) incorporating substituted 2-indolinone moiety (as tail) linked to benzenesulfonamide (as zinc anchoring moiety) through a hydrazide linker. The synthesized sulfonamides were evaluated in vitro for their inhibitory activity against the following human (h) carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, hCA I, II, IX and XII. All these isoforms were inhibited by the sulfonamides reported here in variable degrees. hCA I was inhibited with KIs in the range of 671.8: 3549.5 nM, hCA II in the range of 36.8: 892.4 nM; hCA IX in the range of 8.9: 264.5 nM, whereas hCA XII in the range of 9.0: 78.1 nM. In particular, compound 10b emerged as a single-digit nanomolar hCA IX and XII inhibitor (8.9 and 9.2 nM, respectively). Molecular docking studies carried out for compound 10b within the hCA II, IX and XII active sites allowed us to rationalize the obtained inhibition results.

Pyridine-Ureas as Potential Anticancer Agents: Synthesis and In Vitro Biological Evaluation

In our endeavor towards the development of effective anticancer agents, a novel series of pyridine-ureas 8a⁻n were synthesized. All the newly prepared derivatives were evaluated in vitro for their growth inhibitory activity towards the proliferation of breast cancer MCF-7 cell line. Compounds 8e and 8n were found to be the most active congeners against MCF-7 cells (IC₅₀ = 0.22 and 1.88 µM after 48 h treatment; 0.11 and 0.80 µM after 72 h treatment, respectively) with increased activity compared to the reference drug doxorubicin (IC₅₀ = 1.93 µM). Moreover, eight selected pyridines 8b, 8d, 8e, 8i, 8j and 8l⁻n were evaluated for their in vitro anticancer activity according to the US-NCI protocol. Pyridines 8b and 8e proved to be the most effective anticancer agents in the NCI assay with mean inhibition = 43 and 49%, respectively. Both 8b and 8e exhibited anti-proliferative activity against all tested cancer cell lines from all subpanels growth inhibition (GI for 8b; 12⁻78%, GI for 8e; 15⁻91%). Pyridines 8b and 8e were screened in vitro for their inhibitory activity against VEGFR-2. Both compounds inhibited VEGFR-2 at micromolar IC₅₀ values 5.0 ± 1.91 and 3.93 ± 0.73 µM, respectively. The most active pyridines were filtered according to the Lipinski and Veber rules and all of them passed these filters. Finally, several ADME descriptors were predicted for the active pyridines through a theoretical kinetic study.

Novel Thiazolidinone/Thiazolo[3,2-a]Benzimidazolone-Isatin Conjugates as Apoptotic Anti-proliferative Agents Towards Breast Cancer: One-Pot Synthesis and In Vitro Biological Evaluation

In connection with our research program on the development of new isatin-based anticancer candidates, herein we report the synthesis of two novel series of thiazolidinone-isatin conjugates (4a⁻n) and thiazolo[3,2-a]benzimidazolone-isatin conjugates (7a⁻d), and in vitro evaluation of their antiproliferative activity towards two breast cancer cell lines; triple negative MDA-MB-231, and MCF-7. Compounds 4m and 7b emerged as the most active congeners against MDA-MB-231 cells (IC50 = 7.6 ± 0.5 and 13.2 ± 1.1 µM, respectively). Compounds 4m and 7b were able to provoke apoptosis in MDA-MB-231 cells, evidenced by the up-regulation of Bax and down-regulation of Bcl-2, besides boosting caspase-3 levels. Hybrid 4m induced a fourfold increase in the percentage of cells at Sub-G₁, with concurrent arrest in G₂-M phase by 2.5-folds. Furthermore, hybrid 4m resulted in a sixfold increase in the percentage of annexin V-FITC positive apoptotic MDA-MB-231 cells as compared with the control. Moreover, the cytotoxic activities of the active conjugates were assessed towards two nontumorigenic cell lines (breast MCF-10A and lung WI-38) where both conjugates 4m and 7b displayed mean tumor selectivity index: 9.6 and 13.9, respectively. Finally, several ADME descriptors were predicted for the active conjugates via a theoretical kinetic study.