Novel 3,6-Disubstituted Pyridazine Derivatives Targeting JNK1 Pathway: Scaffold Hopping and Hybridization-Based Design, Synthesis, Molecular Modeling, and In Vitro and In Vivo Anticancer Evaluation.

A series of novel 3,6-disubstituted pyridazine derivatives were designed, synthesized, and biologically evaluated as preclinical anticancer candidates. Compound 9e exhibited the highest growth inhibition against most of the NCI-60 cancer cell lines. The in vivo anticancer activity of 9e was subsequently investigated at two dose levels using the Ehrlich ascites carcinoma solid tumor animal model, where a reduction in the mean tumor volume allied with necrosis induction was reported without any signs of toxicity in the treated groups. Interestingly, compound 9e was capable of downregulating c-jun N-terminal kinase-1 (JNK1) gene expression and curbing the protein levels of its phosphorylated form, in parallel with a reduction in its downstream targets, namely, c-Jun and c-Fos in tumors, along with restoring p53 activity. Furthermore, molecular docking and dynamics simulations were carried out to predict the binding mode of 9e and prove its stability in the JNK1 binding pocket.

An overview of pyridazin-3(2H)-one: a core for developing bioactive agents targeting cardiovascular diseases and cancer.

Cardiovascular diseases (CVDs) and cancer are the top two leading causes of death globally. Vasodilators are commonly used to treat various CVDs. In cancer treatment, targeted anticancer agents have been developed to minimize side effects compared with traditional chemotherapy. Many hypertension patients are more prone to cancer, a case known as reverse cardio-oncology. This leads to the search for drugs with dual activity or repurposing strategy to discover new therapeutic uses for known drugs. Recently, medicinal chemists have shown great interest in synthesizing pyridazinone derivatives due to their significant biological activities in tackling these critical health challenges. This review will concentrate on pyridazin-3(2H)-one-containing compounds as vasodilators and anticancer agents, along with a brief overview of various methods for their synthesis.

[Box: see text].

Insight on Some Newly Synthesized Trisubstituted Imidazolinones as VEGFR-2 Inhibitors.

Two series of ten new 1,2,4-trisubstituted imidazolin-5-ones were synthesized and screened against MCF-7 breast cancer and A549 lung cancer cell lines to test their potential in vitro anticancer activity. The results revealed preferential activity of the tested compounds toward MCF-7 cell lines compared to A549 cell lines. The most promising ten compounds (3a, 3c, 3f, 3g, 3h, 3i, 3j, 6a, 6f, and 6i) were subjected to VEGFR-2 enzyme inhibitory activity testing to further explore their mechanism of action. The tested compounds showed remarkable enzyme inhibition in micromolar concentrations ranging from 0.07 to 0.36 µM, compared with Sorafenib and Sunitinib with IC50 values of 0.06 and 0.12 µM, respectively. The most promising candidate, 3j, was further evaluated for its cell cycle phases, apoptotic induction ability, as well as its antiproliferative activity and inhibitory potential for endothelial cell migration, analyzed by a cell scratch assay. Furthermore, in silico studies were also performed to identify and detect the stability of the binding poses.

Exploring of novel oxazolones and imidazolones as anti-inflammatory and analgesic candidates with cyclooxygenase inhibitory action.

Aim: Over the last few decades, therapeutic needs have led to a search for safer COX-2 inhibitors with potential anti-inflammatory and analgesic activity. Materials & methods: A new series of oxazolone and imidazolone derivatives 3a-c and 4a-r were synthesized and evaluated as anti-inflammatory and analgesic agents. COX-1/COX-2 isozyme selectivity testing and molecular docking were performed. Results: All compounds showed good activities comparable to those of the reference, celecoxib. The most active compounds 3a, 4a, 4c, 4e and 4f showed promising gastric tolerability with an ulcer index lower than that of celecoxib. The molecular docking of p-methoxyphenyl derivative 4c showed alkyl interaction with the side pocket His75 of COX-2 and achieved the best anti-inflammatory activity, with a COX-2 selectivity index better than that of celecoxib.

[Box: see text].

Design, synthesis, and biological evaluation of some new 2-phenyl-3,6-pyridazinedione derivatives as PDE-5 inhibitors.

Various 2-phenyl-3,6-pyridazinedione derivatives 4a-j, 5a-c, 6a,b, 7a-c, 8, 9, 10a-d, and 11a-d, were effectivelysynthesized, and tested for their potential inhibition of phosphodiesterase enzyme at 10 µM. Then fourteen compounds exhibiting the highest inhibition 4b, 4d, 4e, 4g, 4h, 4i, 5a, 6a,b, 7c, 10a,b, 11a, and 11d were selected for screening their PDE-5 inhibition, where compounds 4b,g,h, and 11a revealed promising PDE-5 inhibition having IC50 values = 25, 53, 22, and 42 nM, respectively in comparison with Sildenafil (IC50 = 16 nM). Additionally, these four most active compounds were safe to normal fibroblast cell line WI-38. Moreover, 4f, 4h, 4j, 10d, and 11d had almost the same anti-proliferative effect against the aortic cell line as Sildenafil. Furthermore, molecular docking illustrated that the binding of the target compounds with the key amino acids in the binding site of PDE-5 (PDB 2H42) was like to that of the cocrystallized ligand Sildenafil. Additionally, molecular dynamics simulation for the most active compound 4h revealed high stability of the 4h -PDE5 complex explaining its promising activity as a PDE-5 inhibitor. Therefore, the 2-phenyl-3,6-pyridazinedione scaffold can be considered an important core for designing more promising PDE-5 inhibitors.

Investigations of new N1-substituted pyrazoles as anti-inflammatory and analgesic agents having COX inhibitory activity.

Background: The search is ongoing for ideal anti-inflammatory and analgesic agents with promising potency and reasonable selectivity. Methods: New N1-substituted pyrazoles with or without an acetamide linkage were synthesized and evaluated for their anti-inflammatory and analgesic activities. COX inhibitory testing, molecular docking, molecular dynamics simulation and antiproliferative activity assessments were performed. Results: All compounds exhibited anti-inflammatory activity up to 90.40% inhibition. They also exhibited good analgesic activity with up to 100% protection. N1-benzensulfonamides 3d, 6c and 6h were preferentially selective agents toward COX-2. Compound 3d showed good cytotoxicity against MCF-7 and HTC116 cancer cell lines. Molecular modeling studies predicted the binding pattern of the most active compounds. Molecular dynamics confirmed the docking results. All compounds showed remarkable pharmacokinetic properties.

Insights into targeting SARS-CoV-2: design, synthesis, in silico studies and antiviral evaluation of new dimethylxanthine derivatives.

Aiming to achieve efficient activity against severe acute respiratory syndrome coronavirus (SARS-CoV-2), the expansion of the structure- and ligand-based drug design approaches was adopted, which has been recently reported by our research group. Purine ring is a corner stone in the development of SARS-CoV-2 main protease (Mpro) inhibitors. The privileged purine scaffold was elaborated to achieve additional affinity based on hybridization and fragment-based approaches. Thus, the characteristic pharmacophoric features that are required for the inhibition of Mpro and RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 were utilized along with the crystal structure information of both targets. The designed pathways involved rationalized hybridization with large sulfonamide moieties and a carboxamide fragment for the synthesis of ten new dimethylxanthine derivatives. The synthesis was performed under diverse conditions to afford N-alkylated xanthine derivatives, and cyclization afforded tricyclic compounds. Molecular modeling simulations were used to confirm and gain insights into the binding interactions at both targets' active sites. The merit of designed compounds and the in silico studies resulted in the selection of three compounds that were evaluated in vitro to estimate their antiviral activity against SARS-CoV-2 (compounds 5, 9a and 19 with IC50 values of 38.39, 8.86 and 16.01 µM, respectively). Furthermore, oral toxicity of the selected antiviral candidates was predicted, in addition to cytotoxicity investigations. Compound 9a showed IC50 values of 8.06 and 3.22 µM against Mpro and RdRp of SARS-CoV-2, respectively, in addition to promising molecular dynamics stability in both target active sites. The current findings encourage further specificity evaluations of the promising compounds for confirming their specific protein targeting.

New quinazolinone-based derivatives as DHFR/EGFR-TK inhibitors: Synthesis, molecular modeling simulations, and anticancer activity.

New 2-mercapto-quinazolin-4-one analogs were synthesized and tested for their in vitro anticancer activity, dihydrofolate reductase (DHFR) inhibition, and epidermal growth factor tyrosine kinase (EGFR-TK) inhibition activities. Compound 24, which is characterized by a 2-benzyl-thio function, showed broad-spectrum anticancer activity with high safety profile and selectivity index. The concentrations of 24 causing 50% growth inhibition (GI50 ) and total cell growth inhibition (TGI) and its lethal concentration 50 (LC50 ) were 15.1, 52.5, and 91.2 µM, respectively, using 5-fluorouracil as a positive control. Also, it showed EGFR-TK inhibitory activity with IC50 = 13.40 nM compared to gefitinib (IC50 = 18.14 nM) and DHFR inhibitory potency with 0.30 µM compared to methotrexate (MTX; IC50 = 0.08 µM). In addition, compound 24 caused cell cycle arrest and apoptosis on COLO-205 colon cancer cells. Compounds 37, 21, and 54 showed remarkable DHFR inhibitory activity with IC50 values of 0.03, 0.08, and 0.08 µM, respectively. The inhibitory properties of these compounds are due to an electron-withdrawing group on the quinazolinone ring, except for compound 54. In a molecular modeling study, compound 24 showed the same binding mode as gefitinib as it interacted with the amino acid Lys745 via π-π interaction. Compound 37 showed a similar binding mode as MTX through the binding interaction with Lys68, Asn64 via hydrogen bond acceptor, and Phe31 via arene-arene interaction. The obtained model and substitution pattern could be used for further development.

Exploration of thiazolidine-2,4-diones as tyrosine kinase inhibitors: Design, synthesis, ADMET, docking, and antiproliferative evaluations.

As dual EGFR and VEGFR-2 inhibitors, 22 innovative thiazolidine-2,4-diones were modeled, constructed, and measured for their anticancer performance versus four human neoplasms HCT-116, MCF-7, A549, and HepG2. Molecular docking and MD simulation were performed to inspect the binding technique of the proffered congeners with the EGFR and VEGFR-2 receptors. Evidence realized thanks to the docking inquests was vastly consistent together with that detected through the biological screening. Structures 14a and 14g emerged as the most active compounds toward HCT116 (IC50 = 6.01 and 7.44 µM), MCF-7 (IC50 = 5.77 and 7.23 µM), A549 (IC50 = 5.35 and 5.47 µM) and HepG2 (IC50 = 3.55 and 3.85 µM) tumefaction cells. Compounds 14a and 14g exhibited higher events than sorafenib (IC50 = 5.05, 5.58, 4.04, and 4.00 µM) against HepG2 instead subordinate incidents concerning A549, MCF-7, and HCT116, parallelly. Nevertheless, these compounds signified weightier performance than erlotinib (IC50 = 13.91, 8.20, 5.49, 7.73, and µM), with respect to the four cell lines. Compounds having the best activity against the four cell lines, 12a-f, 13a-d, and 14a-g were chosen to appraise their in vitro VEGFR-2 and EGFRT790M inhibiting activities. The best results were for compounds 14a and 14g compared to sorafenib and erlotinib, respectively, with IC50 values of 0.74 and 0.78 µM and 0.12 and 0.14 µM, respectively. Moreover, 13d, 14a, and 14g showed an adequate in silico calculated ADMET profile. The current investigation presents novel candidates for future optimization to construct mightier and eclectic binary VEGFR-2/EGFRT790M restrainers with higher antitumor effects.

Design and synthesis of some new 6-bromo-2-(pyridin-3-yl)-4-substituted quinazolines as multi tyrosine kinase inhibitors.

The present study involves design and synthesis of five series of 6-bromo-2-(pyridin-3-yl)-4-substituted quinazolines 9a-l, 11a-e, 13a-c, 14a-f and 15a-e. Candidates 9a-l and 11a-e were evaluated for their EGFR and HER2 inhibitory activity compared to Lapatinib. Compounds 9b, 9d, 9f, 11b and 11c were further screened for their in vitro cytotoxicity against two human breast cancer cell lines: AU-565 and MDA-MB-231 in addition to normal breast cell line MCF10A. Compound 9d revealed a remarkable cytotoxic efficacy against AU-565 cell line (IC50 = 1.54 µM) relative to Lapatinib (IC50 = 0.48 µM), whereas compounds 9d and 11c showed a superior cytotoxicity towards MDA-MB-231 (IC50 = 2.67 and 1.75 µM, respectively) in comparison to Lapatinib (IC50 = 9.29 µM). Moreover, compounds 13a-c, 13a-c, 14a-f and 15a-e were tested for their VEGFR-2 inhibitory activity compared to Sorafenib. Compounds 13a, 14c and 14e exhibited remarkable inhibition (IC50 = 79.80, 50.22 and 78.02 nM, respectively) relative to Sorafenib (IC50 = 51.87 nM). In vitro cytotoxicity of these compounds against HepG2, HCT-116 and normal cell (WISH) revealed a superior cytotoxicity against HepG2, HCT-116 especially 13a (IC50 = 17.51 and 5.56 µM, respectively) and 14c (IC50 = 10.40 and 3.37 µM, respectively) compared to Sorafenib (IC50 = 19.33 and 6.82 µM, respectively). Compounds 9d, 11c and 14c were subjected to cell cycle analysis and apoptotic assay. Molecular docking and ADME prediction studies were fulfilled to illustrate the interaction of the potent derivatives with the hot spots of the active site of EGFR, HER2 and VEGFR-2 along with prediction of their pharmacokinetic and physicochemical properties.

Design and synthesis of novel benzimidazole derivatives as potential Pseudomonas aeruginosa anti-biofilm agents inhibiting LasR: Evidence from comprehensive molecular dynamics simulation and in vitro investigation.

Quorum sensing (QS) inhibition is one of the potential methods to target bacterial infection. In this study, comprehensive molecular dynamics simulation (MDS) experiments were conducted on the LasR structure to understand its structural dynamic behavior either in its ligand-free form or in its ligand-bound form (i.e. agonist or antagonist). The results revealed that LasR structure is significantly unstable in its ligand-free and antagonist-bound forms and such structural instability led eventually to complete dissociation of the functioning LasR dimeric form. Accordingly, twenty-eight benzimidazole derivatives were designed, synthesized as potential LasR antagonists, and characterized in vitro as QS inhibitors. Compounds 3d and 7f disclosed the highest percentage inhibition in biofilm formation, pyocyanin, and rhamnolipids production in Pseudomonas aeruginosa (71.70%, 68.70%, 54.00%) and (68.90%, 68.00%, 51.80%), respectively. MDS experiments revealed that these compounds as inhibitors, particularly, 3d, 7f, 8a, and 9g induce LasR structure instability and complete dissociation of its functioning dimeric form similarly to the previously reported inhibitor bromophenethyl-2-nitrobenzamide (BPNB). Furthermore, gene expression assays as another mechanism targeting quorum sensing genes to prove the inhibitory activity of these compounds on virulence factors, revealed that a number of the synthesized compounds were able to downregulate lasR (e.g. 3d and 7f by 61.70% and 26.00%, respectively) and rhlR (e.g. 7f by 16.30%) expressions. The results presented here provide a functional model for LasR that could guide future design of LasR inhibitors.

Design, synthesis, in silico docking, ADMET and anticancer evaluations of thiazolidine-2,4-diones bearing heterocyclic rings as dual VEGFR-2/EGFRT790M tyrosine kinase inhibitors.

Fourteen recent thiazolidine-2,4-diones bearing furan and/or thiophene heterocyclic rings have been designed, synthesized and assessed for their anticancer activities against four human tumor cell lines HepG2, A549, MCF-7 and HCT-116 targeting both VEGFR-2 and EGFR tyrosine kinases. Molecular design was carried out to investigate the binding mode of the proposed compounds with VEGFR-2 and EGFR receptors. HepG2 was the most susceptible cell line to the influence of our derivatives. Compounds 5g and 4g revealed the highest activities against HepG2 (IC50 = 3.86 and 6.22 µM), A549 (IC50 = 7.55 and 12.92 µM), MCF-7 (IC50 = 10.65 and 10.66 µM) and HCT116 (IC50 = 9.04 and 11.17 µM) tumor cell lines. Sorafenib (IC50 = 4.00, 4.04, 5.58 and 5.05 µM) and elotinib (IC50 = 7.73, 5.49, 8.20 and 13.91 µM) were used as reference standards. Furthermore, the most active cytotoxic compounds 4d, 4e, 4f, 4g, 5d, 5e, 5f and 5g were selected to assess their VEGFR-2 inhibitory effects. Derivatives 5g, 4g and 4f were observed to be the highest effective derivatives that inhibited VEGFR-2 at the submicromolar level (IC50 = 0.080, 0.083 and 0.095 µM respectively) in comparison to sorafenib (IC50 = 0.084 µM). As well, compounds 4d, 4e, 4f, 4g, 5d, 5e, 5f and 5g were additionally assessed for their inhibitory activities against mutant EGFRT790M. Compounds 5g and 4g could interfere with the EGFRT790M activity exhibiting stronger activities than elotinib with IC50 = 0.14 and 0.23 µM respectively. Finally, our derivatives 4g, 5f and 5g showed a good in silico calculated ADMET profile. The obtained results showed that our compounds could be useful as a template for future design, optimization, adaptation and investigation to produce more potent and selective dual VEGFR-2/EGFRT790M inhibitors with higher anticancer activity.

Synthesis, molecular modelling and QSAR study of new N-phenylacetamide-2-oxoindole benzensulfonamide conjugates as carbonic anhydrase inhibitors with antiproliferative activity.

In continuation of our previous studies to optimise potent carbonic anhydrase inhibitors, two new series of isatin N-phenylacetamide based sulphonamides were synthesised and screened for their human (h) carbonic anhydrase (EC 4.2.1.1) inhibitory activities against four isoforms hCA I, hCA II, hCA IX and hCA XII. The indole-2,3-dione derivative 2h showed the most effective inhibition profile against hCAI and hCA II (KI = 45.10, 5.87 nM) compared to acetazolamide (AAZ) as standard inhibitor. Moreover, 2h showed appreciable inhibition activity against the tumour-associated hCA XII, similar to AAZ showing KI of 7.91 and 5.70 nM, respectively. The analogs 3c and 3d showed good cytotoxicity effects, and 3c revealed promising selectivity towards lung cell line A549. Molecular docking was carried out for 2h and 3c to predict their binding conformations and affinities towards the hCA I, II, IX and XII isoforms.

Synthesis, in vitro anticancer activity and in silico studies of certain pyrazole-based derivatives as potential inhibitors of cyclin dependent kinases (CDKs).

New diphenyl-1H-pyrazoles were synthesized and screened for CDK2 inhibition where 8d, 9b, 9c, and 9e exhibited promising activity (IC50 = 51.21, 41.36, 29.31, and 40.54 nM respectively) compared to R-Roscovitine (IC50 = 43.25 nM). Furthermore, preliminary anti-proliferative activity screening of some selected compounds on 60 cancer cell lines was performed at the (NCI/USA). Compounds 8a-c displayed promising growth inhibitory activity (mean %GI; 73.74, 94.32 and 74.19, respectively). Additionally, they were further selected by the NCI for five-dose assay, exhibiting pronounced activity against almost the full panel (GI50 ranges; 0.181-5.19, 1.07-4.12 and 1.07-4.82 µM, respectively) and (Full panel GI50 (MG-MID); 2.838, 2.306 and 2.770 µM, respectively). Screening the synthesized compounds 8a-c for inhibition of CDK isoforms revealed that compound 8a exhibited nearly equal inhibition to all the tested CDK isoforms, while compound 8b inhibits CDK4/D1 preferentially than the other isoforms and compound 8c inhibits CDK1, CDK2 and CDK4 more than CDK7. Flow cytometry cell cycle assay of 8a-c on Non-small cell lung carcinoma (NSCL HOP-92) cell line revealed S phase arrest by 8a and G1/S phase arrest by 8b and 8c. Apoptotic induction in HOP-92 cell line was also observed upon treatment with compounds 8a-c. Docking to CDK2 ATP binding site revealed similar interactions as the co-crystallized ligand R-Roscovitine (PDB code; 3ddq). These findings present compounds 8a-c as promising anti-proliferative agents.

Staquorsin: A Novel Staphylococcus aureus Agr-Mediated Quorum Sensing Inhibitor Impairing Virulence in vivo Without Notable Resistance Development.

The emergence of microbial resistance to the available antibiotics is a major public health concern, especially with the limited rate of developing new antibiotics. The utilization of anti-virulence agents is a non-conventional approach that can be used to combat microbial infection. In Staphylococcus aureus, many virulence factors are regulated by the Agr-mediated quorum sensing (QS). We developed a chemical compound that acts a potential Agr-inhibitor without reducing bacterial viability. The compound was designated staquorsin for Staphylococcus aureus QS inhibitor. In silico analyses confirmed the binding of staquorsin to the AgrA active site with an absolute binding score comparable to savirin, a previously described AgrA inhibitor. However, staquorsin turned out to be superior over savarin in not affecting the S. aureus viability in concentrations up to 600 µM. On the other hand, savirin inhibited S. aureus growth in concentrations as low as 25 µM. Moreover, staquorsin proved to be a potent inhibitor of the Agr system by inhibiting hemolysins, lipase production, and affecting biofilms formation and detachment. On the molecular level it significantly inhibited the effector transcript RNA III. In vivo testing, using the murine skin abscess model, confirmed the ability of staquorsin to modulate S. aureus virulence by effectively controlling the infection. Twenty passages of S. aureus in the presence of 40 µM staquorsin have not resulted in loss of activity as evidenced by maintaining its ability to reduce hemolysin production and RNA III transcript levels. In conclusion, we hereby describe a novel anti-virulence compound inhibiting the S. aureus Agr-system and its associated virulence factors. It is active both in vitro and in vivo, and its frequent use does not lead to the development of resistance. These findings model staquorsin as a promising drug candidate to join the fierce battle against the formidable pathogen S. aureus.

3-Methyl-imidazo[2,1-b]thiazole derivatives as a new class of antifolates: Synthesis, in vitro/in vivo bio-evaluation and molecular modeling simulations.

Inhibiting the Dihydrofolate reductase (DHFR) enzyme has been validated in multiple clinical manifestations related to bacterial infection, malaria, and multiple types of cancer. Herein, novel series of 3-methyl-imidazo[2,1-b] thiazole-based analogs were synthesized and biologically evaluated for their in vitro inhibitory profile towards DHFR. Compounds 22 and 23 exhibited potent inhibitory profile targeting DHFR (IC50 0.079 and 0.085 µM, respectively comparable to MTX IC50 0.087 µM). Compounds 22 and 23 showed promising cytotoxicity against MCF7 breast cancer cell lines inducing cell cycle arrest and apoptosis. Furthermore, Compound 23 showed its potential to reduce body weight and tumor volume significantly, using Ehrlich ascites carcinoma (EAC) solid tumor animal model of breast cancer, compared to control-treated groups. Further, molecular modeling simulations validated the potential of 22 and 23 to have high affinity binding towards Arg22 and Phe31 residues via π-π interaction and hydrogen bonding within DHFR binding pocket. Computer-assisted ADMET study suggested that the newly synthesized analogs could have high penetration to the blood brain barrier (BBB), better intestinal absorption, non-inhibitors of CYP2D6, adequate plasma protein binding and good passive oral absorption. The obtained model and pattern of substitution could be used for further development of DHFR inhibitors.

Nanomolar potency of imidazo[2,1-b]thiazole analogs as indoleamine 2,3-dioxygenase inhibitors.

Novel series of imidazo[2,1-b]thiazole analogs were designed, synthesized, and biologically evaluated as indoleamine 2,3-dioxygenase (IDO1) inhibitors. Imidazo[2,1-b]thiazoles 6, 7, and 8 showed inhibitory profiles against IDO1 at IC50 values of 68.48, 82.39, and 48.48 nM, respectively, compared with IDO5L at IC50 67.40 nM. Benzo[d]imidazo[2,1-b]thiazoles 17, 20, and 22 showed promising IDO1 inhibition at IC50 values of 53.58, 53.16, and 57.95 nM, respectively. Compound 7 showed a growth-inhibitory profile at GI of 39.33% against the MCF7 breast cancer cell line, while 8 proved lethal to ACHN renal cancer cells. Cells treated with compounds 17 and 22 showed a typical apoptosis pattern of DNA fragments that reflected the G0/G1, S, and G2/M phases of the cell cycle, together with a pre-G1 phase corresponding to apoptotic cells, which indicates that cell growth arrest occurred at the S phase. Molecular modeling simulations validated the potential of benzo[d]imidazo[2,1-b]thiazole analogs to chelate iron(III) within the IDO1 binding pocket and, hence, to have a better binding affinity via hydrophobic-hydrophobic interactions.

Design, synthesis, and pharmacological characterization of some 2-substituted-3-phenyl-quinazolin-4(3H)-one derivatives as phosphodiesterase inhibitors.

Some 3-phenyl-quinazolin-4(3H)-one-2-thioethers (3a-e, 5a,b, 7a-e, 9a-d, 10a-d, and 12) along with 2-aminoquinazoline derivatives 13a-c were prepared and screened for their in vitro phosphodiesterase (PDE) inhibitory activity. Some compounds such as 7d,e, 9a,b,d, 10a,d, and 13b exhibited promising activity as compared with the non-selective PDE inhibitor IBMX. This inhibitory activity was validated by molecular docking in the active site of PDE7A and PDE4 to investigate their selectivity. Furthermore, the most active compound 10d (IC50 = 1.15 µM) was tested in vivo using behavioral tests. Compound 10d was able to pass the blood-brain barrier and improve scopolamine-induced cognitive deficits. Therefore, this core can be considered as a promising scaffold for further optimization to obtain new compounds with better PDE7A selective inhibition.

Mechanistic selectivity investigation and 2D-QSAR study of some new antiproliferative pyrazoles and pyrazolopyridines as potential CDK2 inhibitors.

Novel series of diphenyl-1H-pyrazoles (4a-g) and pyrazolo[3,4-b]pyridines (5a-g and 7a-i) were synthesized and evaluated for their antiproliferative activity against breast cancer cell line (MCF7) and Hepatocellular carcinoma cell line (HepG2). The highest MCF7 growth inhibition activity was attained via compounds 4f and 7e (IC50 = 1.29 and 0.93 µM, respectively), while compounds 5b and 7f were the most active ones against HepG2 (IC50 = 1.57 and 1.33 µM, respectively) compared to doxorubicin (IC50 = 1.88 and 7.30 µM, respectively). Cell cycle analysis showed arrest at S and G2-M phases in MCF7 cells treated with 4f and 7e, and at G2-M and G1/S phases in HepG2 cells treated with 5b and 7f, respectively. Apoptotic effect of compounds 4f, 5b, 7e, and 7f was indicated via their pre-G1 early and late apoptotic effects and augmented levels of caspase-9/MCF7 and caspase-3/HepG2. A worthy safety profile was assessed for compounds 4f and 7e on MCF10A and compounds 5b and 7f on THLE2 treated normal cells. Furthermore, compounds 4f, 5b and 7f displayed a promising selective profile for CDK2 inhibition vs. CDK1, CDK4, and CDK7 isoforms as proved from their selectivity index. Docking in CDK2 ATP binding site, co-crystallized with R-Roscovitine, demonstrated analogous interactions and comparable binding energy with the native ligand. 2D QSAR sighted the possible structural features governing the CDK2 inhibition activity elicited by the studied pyrazolo[3,4-b]pyridines. These findings present compounds 4f, 5b, and 7f as selective CDK2 inhibitors with promising antiproliferative activity against MCF7 and HepG2 cancer cells.

Design, synthesis and in silico insights of new 7,8-disubstituted-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione derivatives with potent anticancer and multi-kinase inhibitory activities.

Aiming to obtain an efficient anti-proliferative activity, structure- and ligand-based drug design approaches were expanded and utilized to design and refine a small compound library. Subsequently, thirty-two 7,8-disubstituted-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione derivatives were selected for synthesis based on the characteristic pharmacophoric features required for PI3K and B-Raf oncogenes inhibition. All the synthesized compounds were evaluated for their in vitro anticancer activity. Compounds 17 and 22c displayed an acceptable potent activity according to the DTP-NCI and were further evaluated in the NCI five doses assay. To validate our design, compounds with the highest mean growth inhibition percent were screened against the target PI3Kα and B-RafV600E to confirm their multi-kinase activity. The tested compounds showed promising multi-kinase activity. Compounds 17 and 22c anticancer effectiveness and multi-kinase activity against PI3Kα and B-RafV600E were consolidated by the inhibition of B-RafWT, EGFR and VEGFR-2 with IC50 in the sub-micromolar range. Further investigations on the most potent compounds 17 and 22c were carried out by studying their safety on normal cell line, in silico profiling and predicted ADME characteristics.