Novel VEGFR-2 inhibitors as antiangiogenic and apoptotic agents via paracrine and autocrine cascades: Design, synthesis, and biological evaluation.

Appertaining to its paracrine and autocrine signaling loops, VEGFR-2 succeeded in grabbing attention as one of the leading targets in cancer treatment. Based on the foregoing and our comprehensive studies regarding pharmacophoric features and activity of sorafenib, novel phenylpyridazinone based VEGFR-2 inhibitors 4, 6a-e, 7a,b, 9a,b, 12a-c, 13a,b, 14a,b, 15a,b, and 17a-d were optimized. An assortment of biological assays was conducted to assess the antiangiogenic and apoptotic activities of the synthesized derivatives. In vitro VEGFR-2 kinase assay verified the inhibitory activity of the synthesized derivatives with IC50 values from 49.1 to 418.0 nM relative to the reference drug sorafenib (IC50 = 81.8 nM). Antiproliferative activity against HUVECs revealed that compounds 2-{2-[2-(6-oxo-3-phenylpyridazin-1(6H)-yl)acetyl]hydrazineyl}-N-(p-tolyl)acetamide (12c) and 2-[(5-mercapto-4-methyl-4H-1,2,4-triazol-3-yl)methyl]-6-phenylpyridazin-3(2H)-one (13a) possessed superior activity (IC50 values = 11.5 and 12.3 nM, respectively) in comparison to sorafenib (IC50 = 23.2 nM). For the purpose of appraising their antiproliferative effect, derivatives 12c and 13a were exposed to cell cycle analysis, apoptotic, cell invasion and migration assays in addition to determination of VEGFR-2 in protein level. Moreover, cytotoxicity as well as selectivity index against WI-38 cell line was measured to examine safety of derivatives 12c and 13a. After that, molecular docking study was executed on the top five compounds in the in vitro VEGFR-2 kinase assay 6d, 12c, 13a, 14a and 17c to get a deep perception on binding mode of the synthesized compounds and correlate the design strategy with biological results. Finally, physicochemical, pharmacokinetic properties, and drug-likeness studies were performed on the top five derivative in in vitro VEGFR-2 kinase assay.

Scaffold Repurposing Reveals New Nanomolar Phosphodiesterase Type 5 (PDE5) Inhibitors Based on Pyridopyrazinone Scaffold: Investigation of In Vitro and In Silico Properties.

Inhibition of PDE5 results in elevation of cGMP leading to vascular relaxation and reduction in the systemic blood pressure. Therefore, PDE5 inhibitors are used as antihypertensive and antianginal agents in addition to their major use as male erectile dysfunction treatments. Previously, we developed a novel series of 34 pyridopyrazinone derivatives as anticancer agents (series A-H). Herein, a multi-step in silico approach was preliminary conducted to evaluate the predicted PDE5 inhibitory activity, followed by an in vitro biological evaluation over the enzymatic level and a detailed SAR study. The designed 2D-QSAR model which was carried out to predict the IC50 of the tested compounds revealed series B, D, E and G with nanomolar range of IC50 values (6.00-81.56 nM). A further docking simulation model was performed to investigate the binding modes within the active site of PDE5. Interestingly, most of the tested compounds showed almost the same binding modes of that of reported PDE5 inhibitors. To validate the in silico results, an in vitro enzymatic assay over PDE5 enzyme was performed for a number of the promising candidates with different substitutions. Both series E and G exhibited a potent inhibitory activity (IC50 = 18.13-41.41 nM). Compound 11b (series G, oxadiazole-based derivatives with terminal 4-NO2 substituted phenyl ring and rigid linker) was the most potent analogue with IC50 value of 18.13 nM. Structure-activity relationship (SAR) data attained for various substitutions were rationalized. Furthermore, a molecular dynamic simulation gave insights into the inhibitory activity of the most active compound (11b). Accordingly, this report presents a successful scaffold repurposing approach that reveals compound 11b as a highly potent nanomolar PDE5 inhibitor worthy of further investigation.

Design and synthesis of novel coumarin derivatives as potential acetylcholinesterase inhibitors for Alzheimer's disease.

Twenty novel 7-benzyloxycoumarin based compounds were synthesized with a variety of bioactive chemical fragments. The synthesized compounds showed remarkable acetylcholinesterase (AChE) inhibitory activity. In vitro assay revealed that compounds 7-benzyloxy-4-{[(4-phenylthiazol-2(3H)-ylidene)hydrazono]methyl}-2H-chromen-2-one (5b, IC50= 0.451µM), 7-benzyloxy-4-({[4-(4-methoxyphenyl)thiazol-2(3H)-ylidene]hydrazono}methyl)-2H-chromen-2-one (5d, IC50= 0.625µM), 5-amino-1-[2-(7-benzyloxy-2-oxo-2H-chromen-4-yl)acetyl]-1H-pyrazole-4-carbonitrile (13c, IC50= 0.466µM), 2-(7-benzyloxy-2-oxo-2H-chromen-4-yl)-N-(2-methylimino-4-phenylthiazol-3(2H)-yl)acetamide (16a, IC50= 0.500µM) and 2-(7-benzyloxy-2-oxo-2H-chromen-4-yl)-N-[4-(4-methoxyphenyl)-2-methyliminothiazol-3(2H)-yl]acetamide (16b, IC50= 0.590µM) exhibited promising AChE inhibitory activity even better than donepezil (IC50= 0.711µM). Kinetic study for compound 5b implied mixed type inhibitor which could bind peripheral anionic site (PAS) and catalytic active site (CAS) of AChE enzyme. In addition, in vivo evaluation of compounds 5b, 13c and 16a confirmed significant memory improvement in scopolamine-induced impairment model in tested mice. Furthermore, in silico studies were performed on the synthesized compounds which included molecular docking study at the active site of recombinant human acetylcholinesterase enzyme (rhAChE) as well as prediction of ADMET and other physicochemical parameters. A correlation between the docking results and IC50 of tested compounds was routinely observed and shared similar binding pattern to the co-crystallized ligand donepezil.

Synthesis of new hexahydropyrimido[1,2-a]azepine derivatives bearing functionalized aryl and heterocyclic moieties as anti-inflammatory agents.

New hexahydropyrimido[1,2-a]azepine derivatives bearing functionalized aryl and heterocyclic moieties were synthesized as anti-inflammatory agents with better safety profiles. All synthesized compounds were assessed in vitro for their COX-1 and COX-2 inhibition activities. The most selective compounds, 2f, 5 and 6, were further evaluated for their in vivo anti-inflammatory activity and PGE2 inhibitory activity. To rationalize their selectivity, molecular docking within COX-1 and COX-2 binding sites was performed. Their physicochemical properties and drug-like nature profile were also calculated. The good activity and selectivity of compounds 2f, 5 and 6 were rationalized using a molecular docking study and supported by in vivo studies. These promising findings are encouraging for performing future investigations of these derivatives.

New pyrazole derivatives: Synthesis, anti-inflammatory activity, cycloxygenase inhibition assay and evaluation of mPGES.

New pyrazole derivatives 2-5 were synthesized and evaluated for their COX-1 and COX-2 inhibitory activity in vitro. All compounds showed good inhibitory activity at a nanomolar level and most compounds exhibited selectivity towards COX-2 inhibition. Compounds 2a, 3b, 4a, 5b and 5e exhibited IC50 towards COX-2 enzyme of 19.87, 39.43, 61.24, 38.73 and 39.14 nM, respectively. Furthermore, compounds 3b, 4a, 5b and 5e exhibited a selectivity index of 22.21, 14.35, 17.47 and 13.10, respectively. The most active compounds were further subjected to in vivo anti-inflammatory assay. The tested compounds showed better or comparable activity to celecoxib as positive control. In order to explore their binding mode and selectivity behaviour, molecular docking in the active site of COX-2 was carried out for these derivatives. Analysis of the docked poses of the compounds showed that they adopt similar conformations to the highly selective COX-2 inhibitor, SC-558. The docking pose of compound 3b was confirmed by molecular dynamics. All the tested compounds exhibited potent inhibitory effect on the production of PGE2, in addition to their inhibition of COX-2 enzyme.

Synthesis and Anticancer Evaluation of Some New 3-Benzyl-4,8-Dimethylbenzopyrone Derivatives.

INTRODUCTION: New benzopyrone derivatives such as Schiff's like compounds, acetohydrazides or substituted with oxadiazole or pyrazole heterocycles were synthesized from parent acid hydrazide compound 3. METHODS AND MATERIALS: Structures of the synthesized compounds were elucidated using IR, NMR and mass spectroscopy. All the synthesized derivatives were selected by National Cancer Institute (NCI), Bethesda, and evaluated for their in vitro anticancer activity in the full NCI 60 cell lines panel assay. RESULTS AND CONCLUSION: Schiffs like compounds 4a, b and c were found to have good growth inhibition % against numerous cell lines that belong mainly to leukemia, non-small cell lung, CNS and breast Cancer subpanels.

Novel pyrazolopyrimidines: Synthesis, in vitro cytotoxic activity and mechanistic investigation.

A series of novel pyrazolo[3,4-d]pyrimidines bearing benzenesulfonamide moiety 5a-f, 6 and 7 were synthesized. Cytotoxic screening was conducted against MCF-7 and HepG2. 6-(4-Methoxyphenyl)-4-oxopyrazolopyrimidine derivative 5e and 4-imino-6-oxopyrazolopyrimidine derivative 6 revealed potent cytotoxic activity with IC50 1.4 µM (MCF-7) and 0.4 µM (HepG2), respectively compared to that of doxorubicin, (IC50 = 1.02 µM and 0.9 µM, respectively). Compounds 5e and 6 were subjected to cell cycle analysis and apoptosis assay after 24 h and 48 h treatment. Compound 5e arrested cell at G1 phase, while 6 arrested cell at S and G2/M phases, respectively. The apoptotic effect of both compounds were evidenced by pre G1 apoptosis as its percentage increased by time (7.38%, 11.61%) and (13.92%, 16.71%), respectively. Apoptosis induction capability was confirmed by the effect on early and late apoptosis and augmentation of caspase-3 level. Furthermore, compound 6 inhibited CDK2 enzyme with IC50 = 0.19 µM and increased levels of its regulators, P21 and P27 by 10.06% and 8.5%, respectively. Moreover, a molecular docking study of compound 6 on CDK2 enzyme was adopted to explore binding interaction with amino acid residues of its active site.

Synthesis, docking and in vitro anticancer evaluation of some new benzopyrone derivatives.

The synthesis of some new 3-alkyl-7-hydroxy-4-methyl-8-substituted-1H-benzopyran-2-ones, 6-alkyl-7-methyl-2-substituted amino-5H-pyrano[6,5-e] benzoxazol-5-ones, 7-alkyl-8-methyl-3-substituted-2,6-dihydropyrano[6,5-f]-1,4-benzoxazin-6-ones, 7,8-disubstituted-3-ethyl-4-methyl-1H-benzopyran-2-ones and 3-alkyl-4-methyl-7-substituted-1H-benzopyran-2-ones were described. Fourteen compounds were selected by National Cancer Institute (NCI), Bethesda, and evaluated for their in vitro anticancer activity in the full NCI 60 cell lines panel assay by a single dose test. Compounds 4a, 18a, 18b and 23a were found to be broad-spectrum antitumors showing effectiveness toward numerous cell lines that belong to different tumor subpanels. Furthermore, docking studies were undertaken to gain insight into the possible binding mode of these compounds with the binding site of the casein kinase II (CK2) enzyme which is involved in cell survival and proliferation through a number of downstream effectors.

New series of 6-substituted coumarin derivatives as effective factor Xa inhibitors: synthesis, in vivo antithrombotic evaluation and molecular docking.

Despite recent progress in antithrombotic therapy, there's still an unmet medical need for safe and orally available anticoagulants. Encouraged by the marked antithrombotic and anticoagulant activities of some coumarin derivatives, twenty-three new N-coumarinyl-4-amidinobenzamides 4a-f and 6-heterocycle substituted coumarin derivatives 5, 6a,b, 10a-e, 12a-e and 14a-d were synthesized and evaluated for their in vivo antithrombotic activity. The most active congeners were the unsubstituted amidine 4a (36.5 s), coumarinyl oxadiazole 5 (42.3 s), bis coumarinyl oxadiazole 6b (37.8 s) and coumarinyl pyrazole 10b (38.5 s) that presented prothrombin time (PT) values comparable to the reference drug warfarin (42.3 s). Furthermore, docking studies were undertaken to gain insight into the possible binding mode of these compounds with the coagulation factor Xa (FXa) binding site.

Synthesis of 3-substituted-2-oxoindole analogues and their evaluation as kinase inhibitors, anticancer and antiangiogenic agents.

Several analogues of the 3-substituted-2-oxoindole chemotype were synthesized by condensing isatin or the appropriate haloisatin with some amino acids or histamine under neutral conditions. All the imino derivatives produced were tested for kinase inhibitory properties against three serine/threonine kinases, namely CDK1/cyclin B, CDK5/p25 and GSK3alpha/beta. Most of the histidine derivatives showed inhibitory properties to the three kinases in the low micromolar range. The histamine derivatives were less potent against CDK1/cyclin B and CDK5/p25 and totally inactive against GSK3alpha/beta. So, the management of the carboxyl function may be a tool to impart selectivity in such family of kinases. Docking of 2-[[-5-bromo-2-oxoindolin-3-ylidene]amino]-3-(1H-imidazol2-yl)propanoic acid 14 to CDK5/p25 indicates that this compound can interact with the enzyme through four hydrogen bonds; for GSK/3beta, the ligand poses itself in another orientation, also four hydrogen bonds can be formed between the ligand and the receptor, otherwise hydrophobic interactions seem to predominate. Also, all the final compounds were tested for their in vitro antitumor properties against MCF7 (breast), NCI-H460 (lung) and SF268 (CNS) cancer cell lines. None of the synthesized compounds was cytotoxic at 10(-4) molar concentration. Moreover, compounds 13 and 14 were tested for potential antiangiogenic properties by testing their ability to inhibit the proliferation of human umbilical vein endothelial cells (HUVECs), cord formation and migration in response to chemoattractant. Only compound 14 showed moderate inhibitory properties to HUVECs proliferation and cord formation while its non-brominated derivative 13 did not. Thus, the antiangiogenesis properties are not apparently caused by inhibition of any of the tested kinases.