Multi-targeted anti-Alzheimer's agents: Synthesis, biological evaluation, and molecular modeling study of some pyrazolopyridine hybrids.

A new series of compounds bearing a pyrazolopyridine scaffold was synthesized as integrated anti-Alzheimer's disease (AD) multi-targeted ligands. Compounds 49 and 51 showed remarkable activity as hAChE inhibitors with IC50 values of 0.17 and 0.16 µM, respectively; and proved to be active hBuChE inhibitors with IC50 values 0.17 and 0.69 µM, eight and two-fold more active than the reference compound rivastigmine, respectively. Compounds 49 and 51 showed potent GSK3ß inhibition with IC50 values of 0.21 and 0.26 µM, respectively compared to L807mts. Also, 49 and 51 showed 66.0 and 60.0% as tau protein aggregation inhibitors; and Aß1-42 self-aggregation inhibitors with 79.0 and 75.0% respectively. Furthermore, 49 and 51 could bind virtually with the PAS affecting Aß aggregation, thus preventing Aß-dependent neurotoxicity. They proved to have the ability to chelate bio-metals such as Fe2+, Cu2+, and Zn2+ preventing their oxidative damage in the brain of AD patients, in addition to their safety upon WI-38 cell line. Both compounds could virtually penetrate BBB and obeyed Lipinski's rule of five. Compounds 49 and 51 could be considered as MTDLs for AD patients and the obtained model and pattern of substitution could be used for further development of new multi-targeted anti-Alzheimer's agents.

New thiazole-based derivatives as EGFR/HER2 and DHFR inhibitors: Synthesis, molecular modeling simulations and anticancer activity.

New series of thiazole and imidazo[2,1-b]thiazole derivatives were synthesized and tested for their in vitro anticancer activity. Compounds 27, 34, 39 and 42-44 showed the best anticancer activity against the tested cancer cell lines with high safety profile and selectivity indices, especially MCF-7 breast cancer, compared to sorafenib. As an attempt to reveal their mode of cytotoxicity, EGFR, HER2 kinase and DHFR inhibition assays were performed. Compounds 39 and 43 were the most potent dual EGFR/HER2 kinase inhibitors, with IC50 values of 0.153 (EGFR), 0.108 (HER2) and 0.122 (EGFR), 0.078 (HER2) µM, respectively. 39 and 42 were the best DHFR inhibitors showing IC50 0.291 and 0.123 µM, respectively. 39 and 43 induced their cytotoxicity via cell cycle arrest at G1/S and G1 phases, respectively, and apoptosis rather than necrosis in the MCF-7 breast cancer cell line. In vivo anti-breast cancer assay of 39 and 43 showed significant tumor volume reduction with recovered caspase-3 immunoexpression. Modeling study results proved the importance of the 5-(4-substituted phenyl)-imidazo[2,1-b]thiazole moiety and the hydrazide side chain for the anticancer activity. The most potent compounds showed good drug-likeness features and could be used as prototypes for further optimization. 39 could be an example of a multi-targeting anticancer agent that acts by inhibiting EGFR/HER2 kinase, DHFR enzymes and cellular apoptosis.

New phthalimide-based derivatives as EGFR-TK inhibitors: Synthesis, biological evaluation, and molecular modeling study.

A novel series of phthalimide derivatives was synthesized and evaluated for in vitro antitumor activity against six human cancer cell lines; HepG-2, HCT-116, MCF-7, Hep2, PC3 and Hela.The obtained results revealed that compound 32 was the most potent antitumor, while compounds 33, 22 and 24 showed strong activity against all tested cell lines. Further biological evaluation of the most active compounds was done and their in vitro EGFR-TK inhibition was tested, and the results came in accordance with the results of antitumor testing, where 32 displayed promising inhibitory activity (IC50 = 0.065 µM) compared to the standard drug erlotinib (IC50 = 0.067 µM). In addition, compounds 48, 22, 28 and 19 showed strong inhibitory activity (IC50 = 0.089, 0.093, 0.147 and 0.152 µM respectively). Cell cycle analysis was conducted and the results revealed that 32 induced cell cycle arrest on Hela and MCF-7 at G0-G1 phase and Pre-G1 phase causing cell death mainly via apoptosis. Additionally, in vivo antitumor screening revealed that 32 reduced both body weight and tumor volume in solid tumor utilizing Ehrlich ascites carcinoma (EAC) animal model. Molecular modeling study showed that 32 and 48 have the highest affinity for binding with the active site of EGFR-TK with docking score comparable to erlotinib. Compounds 32 and 48 could be used as template models for further optimization.

Synthesis, biological evaluation, and molecular modeling simulations of new heterocyclic hybrids as multi-targeted anti-Alzheimer's agents.

The widespread and the recognition of the multifactorial nature of Alzheimer disease (AD) increased the demands for multi-targeted directed ligands (MTDLs) to overcome possible drug-drug interactions of the combination therapy, and to acquire superior therapeutic profile than single targeted molecules. Two main scaffolds namely: pyrazolopyridine and tetrahydroacridine (THA) were used to synthesize four different series of integrated multi-targeted synthons possessing ChE (hAChE or hBuChE), Aß1-42 aggregation inhibition potency, in addition to optimum metal chelating capability. Structure modifications were performed to 9-amino function of THA core of tacrine and the pyrazolopyridine scaffolds linked to a variety of cyclic secondary amines directly or using amide spacers or ethylamine bridge or engaging THA with pyrazolopyridine to produce hybrid compounds. Different 9-amino substitutions improved the in vitro hAChE activity of 7- or 6,7-disubstituted THA derivatives. Compounds 16 and 28 proved to be multimodal anti-AD agents as they were potent hAChE inhibitors, in addition, they could bind with the amino acids of the peripheral anionic site (PAS) affecting Aß aggregation and hence Aß-dependent neurotoxicity especially compound 16 which was almost twofold more active than donepezil. Furthermore, both compounds directly inhibited Aß1-42 self-aggregation and chelated bio-metals such as Fe2+, Zn2+ and Cu2+ preventing reactive oxygen species (ROS) generation by Aß and its oxidative damage in the brain regions of AD patients. Compound 28 had superior privilege by its dual ChE activity resulting in better cognitive improvement. Compounds 16 and 28 showed acceptable relative safety upon hepG2 cell line and excellent BBB penetration with wide safety margin as their LD50 were higher than 120 mg/kg.

New tilomisole-based benzimidazothiazole derivatives as anti-inflammatory agents: Synthesis, in vivo, in vitro evaluation, and in silico studies.

New tilomisole-based benzimidazothiazole derivatives were designed and synthesized in this work. Their anti-inflammatory activity was assessed through the in vivo carrageenan rat paw edema model, and the in vitro COX inhibition assay. Compounds 13, 20, 30, 40, 43, and 46 demonstrated values of inhibition of induced edema in the in vivo assay comparable to celecoxib. All the synthesized compounds expressed their activity on COX-2 enzyme more than COX-1, proving their advantageous selectivity. In addition, compounds 13, 16, 20, 25, and 46 displayed lower IC50 values than celecoxib as a reference drug against COX-2 enzyme; having values of 0.09, 13.87, 32.28, 33.01, and 5.18 nM respectively vs 40.00 nM for celecoxib. Particularly, the most active compound (13) with its extreme potency (400 folds more potent than celecoxib) exhibited a notable high selectivity index (SI = 159.5). In silico studies, including ADMET prediction, compliance to Lipinski's rule of five, and molecular docking into the active site of both COX isozymes were conducted for the synthesized compounds. The results suggested that these compounds are good candidates for orally active drugs, and docking revealed higher number of interactions with COX-2 for 13 as the most active compound compared with COX-1 reflecting its advantageous selectivity and explaining its extreme potency.

Targeting EGFR tyrosine kinase: Synthesis, in vitro antitumor evaluation, and molecular modeling studies of benzothiazole-based derivatives.

New benzothiazole-based derivatives were synthesized in the present work with the aim of evaluating their antitumor activity. They were in vitro tested against hepatocellular carcinoma (HepG2), colorectal carcinoma (HCT-116), mammary gland cancer (MCF-7), prostate cancer (PC-3), and epithelioid carcinoma (HeLa). The results of the in vitro antitumor evaluation revealed that the most active compounds were 39, 40, 51, 56, and 61 exhibiting IC50 values comparable to the reference drug lapatinib. The most active compounds were further subjected to EGFR inhibitory activity assay to rationalize their potency mode. Notably, the most active antitumor compounds 39 and 40 represented the most potent inhibitors to EGFR with IC50 values of 24.58 and 30.42 nM respectively in comparison with 17.38 nM for lapatinib as a standard drug. Molecular modeling studies were also conducted for the synthesized compounds, including docking into EGFR active site and surface mapping. Results proved the superior binding of the hydrazone derivatives 39 and 40 with EGFR suggesting them as good candidates for targeted antitumor therapy through EGFR kinase inhibition.

Synthesis, antitumor testing and molecular modeling study of some new 6-substituted amido, azo or thioureido-quinazolin-4(3H)-ones.

A new series of 6-substituted amido, azo or thioureido-quinazolin-4(3H)-one was synthesized and tested for their in-vitro antitumor activity. Compounds 21, 53 and 60 showed broad spectrum antitumor activity with average IC50 values of 6.7, 7.6 and 9.1 µM, respectively compared with methotrexate (1, IC50 19.26 µM). As an attempt to reveal the mechanism of the antitumor potency, cell cycle analysis and DHFR inhibition were performed. Compounds 59 and 61 induced their cytotoxicity in Hela (IC50 10.6 µM) and HCT-116 (IC50 15.5 µM) cell lines, respectively through Pre-G1 apoptosis, inhibiting cell growth at G2-M phase. Compounds 29, 33, 59 and 61 showed DHFR inhibitory potency at IC50 0.2, 0.2, 0.3 and 0.3 µM, respectively. The active DHFR inhibitors showed high affinity binding toward the amino acid residues Thr56, Ser59 and Ser118. The active compounds obeyed Lipinski's rule of five and could be used as template model for further optimization.

Targeting hepatocellular carcinoma: Synthesis of new pyrazole-based derivatives, biological evaluation, DNA binding, and molecular modeling studies.

A new series of pyrazole derivatives was prepared in this work, including pyrazolopyrimidines, pyrazolotriazines, pyrazolylthienopyridines, and 2-(pyrazolylamino)thiazol-4-ones, utilizing 3-amino-5-methyl-1H-pyrazole as a synthetic precursor. Their in vitro anticancer activity was tested on hepatocellular carcinoma cell line, HepG2. The results revealed that the pyrazolylhydrazonoyl cyanide 8, the pyrazolopyrimidine 3, and the pyrazolylaminothiazolone 17 were the most active with IC50 values of 2, 7, and 7 µM respectively in comparison with 5.5 µM for cisplatin as a reference drug. Interestingly, all the synthesized compounds showed higher selectivity index than cisplatin. DNA binding assay was also carried out for the synthesized compounds to rationalize their mechanism of action. Molecular modeling studies, including docking into DNA minor groove, flexible alignment, and surface mapping, were conducted. Results obtained proved the superior DNA-binding affinity of the most active anticancer compounds.

New benzimidazothiazole derivatives as anti-inflammatory, antitumor active agents: Synthesis, in-vitro and in-vivo screening and molecular modeling studies.

A new series of benzimidazothiazole derivatives has been synthesized. The structure of the products was confirmed by spectroscopic techniques such as IR, NMR and mass spectroscopy. The tested compounds were evaluated for their anti-inflammatory activity either in vitro through the COX enzyme inhibition assay, or in vivo through carrageenan paw edema technique. Results revealed that compound 25 and 29 represented the most active ones among the entire series with % inhibition 72.19, 72.07 for COX-1, and 87.46, 87.38 for COX-2, respectively. Interestingly, all synthesized compounds exhibited IC50 values less than both reference drugs celecoxib and naproxen, indicating their superior potency. For compound 25, it showed about 340 and 198 times more potent than celecoxib and naproxen respectively as COX-1 inhibitor (IC50 value 0.044 vs. 15.000 and 8.700 µM), and 10 and 115 times more potent than the same drugs as COX-2 inhibitor (IC50 value 4.52 vs. 40.00 and 520.00 nM). The antitumor activity of the products was also evaluated and the results obtained are consistent with those obtained by the anti-inflammatory screening where compounds 25 and 29 proved to be the most active ones among the other compounds with %GI ranging from 31.5 to 62.5% and they exhibited the lowest IC50 values as well. The ADMET analysis of the tested compounds was also performed in addition to the molecular modeling studies that included flexible alignment, surface and electrostatic maps in addition to the Lipinisk's rule of five.

Synthesis and biological evaluation of new curcumin analogues as antioxidant and antitumor agents: molecular modeling study.

New curcumin analogues have been synthesized and their antioxidant activities were investigated by measuring their free radical scavenging capacities. The in vitro and in vivo antitumor activities of the synthesized compounds on Ehrlich ascites carcinoma (EAC) cell line were evaluated. 4-(4-Chlorophenyl)-2-(5-ethyl-7-(4-methoxybenzylidene)-3-(4-methoxyphenyl)-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c] pyridin-2-yl)thiazole 7h showed excellent antineoplastic activity in both in vitro and in vivo studies more than that of tested compounds and reference drug, cisplatin. Different molecular modeling studies were performed, where docking of compound 7h into telomerase active site suggested that it could exert its antitumor potential by telomerase inhibition.

Synthesis, in vitro anticancer evaluation and in silico studies of novel imidazo[2,1-b]thiazole derivatives bearing pyrazole moieties.

A series of imidazo[2,1-b]thiazoles bearing pyrazole moieties 4-6(a-c) was synthesized through the reaction of 6-hydrazinylimidazo[2,1-b]thiazoles 3a-c with different ß-dicarbonyl compounds. Eleven compounds were screened at the National Cancer Institute (NCI), USA for anticancer activity at a single dose (10 µM). The in vitro anticancer evaluation revealed that compounds 2a and 4-6(a) exhibited increased potency towards CNS SNB-75 and Renal UO-31 cancer cell lines. COMPARE analyses showed strong to considerable correlations with rapamycin (mTOR inhibitor). The results of assessment of toxicities, druglikeness, and drug score profiles of compounds 2a and 4-6(a) are promising. Some of the target compounds showed good docking scores with potential anticancer targets, chosen based on pharmacophore mapping of the established derivatives.

Novel acetamidothiazole derivatives: synthesis and in vitro anticancer evaluation.

A novel series of acetamide derivatives possessing both 2-imino-4-arylthiazoles and morpholine or different piperazines were synthesized and characterized by IR, (1)H NMR, (13)C NMR, elemental and mass spectral analyses. Twelve compounds were granted NSC codes at National Cancer Institute (NCI), USA for anticancer activity at a single high dose (10(-5) M) in full NCI 60 cell panel. Among the compounds tested, compounds 5a and 6b were found to be the most active candidates of the synthesized series. Assessment of toxicities, druglikeness, and drug score profiles of compounds 5a and 6b are promising. Some of the synthesized compounds showed a good docking score with potential anticancer targets, chosen based on pharmacophore mapping of the established derivatives.