Mamdouh M. Ali

Celecoxib analogs bearing benzofuran moiety as cyclooxygenase-2 inhibitors: Design, synthesis and evaluation as potential anti-inflammatory agents

Novel series of celecoxib analogs endowed with benzofuran moiety 3a-e and 9a-d were synthesized and evaluated for COX-1/COX-2 inhibitory activity in vitro. The most potent and selective COX-2 inhibitors - compounds 3c, 3d, 3e, 9c and 9d - were assessed for their anti-inflammatory activity and ulcerogenic liability in vivo. The 3-(pyridin-3-yl)pyrazole derivatives 3c and 3e exhibited the highest anti-inflammatory activity, that is equipotent to celecoxib. Furthermore, the tested compounds proved to have better gastric safety profile compared to celecoxib. In particular, compound 3e demonstrated about 40% reduction in ulcerogenic potential relative to the reference drug. Finally, molecular docking simulation of the new compounds in COX-2 active site and drug likeness studies showed good agreement with the obtained pharmaco-biological results.

Synthesis and anticancer effects of some novel pyrazolo[3,4-d]pyrimidine derivatives by generating reactive oxygen species in human breast adenocarcinoma cells.

A series of novel substituted pyrazolo[3,4-d]pyrimidines (compounds 2-12) were synthesized starting with pyrimidinone derivative 1. Their in vitro cytotoxicity against human breast adenocarcinoma (MCF-7) cell lines has been investigated and most of the tested compounds exploited potent cytotoxic activity against MCF-7 cell lines comparable to the activity of the commonly used anticancer drug cisplatin. Treatment of MCF-7 cells with increased doses (2, 5, 10, 20 μg/ml) of the tested compounds revealed that the activity of superoxide dismutase and the level of hydrogen peroxide were significantly increased, while the activities of catalase and glutathione peroxidase and the levels of reduced glutathione were significantly lowered compared with control MCF-7 cells. In general, acyclic nucleoside derivative 4 revealed the highest anticancer activity among the other tested compounds.

Synthesis and in vitro cytotoxic activity of novel pyrazolo[3,4-d]pyrimidines and related pyrazole hydrazones toward breast adenocarcinoma MCF-7 cell line

New series of pyrazolo[3,4-d]pyrimidines (7a-e and 13a-d) and pyrazole hydrazones 17a-d were synthesized and evaluated for their antiproliferative activity against human breast adenocarcinoma MCF-7 cell line. Most of the tested compounds exploited potent to moderate growth inhibitory activity, in particular compound 7e exhibited superior potency to the reference drug cisplatin (IC(50)=7.60 and 13.29 μM, respectively). The antitumor activity of the new compounds was accompanied by significant increase in the activity of superoxide dismutase with concomitant decrease in the activities of catalase and glutathione peroxidase and reduced glutathione level. Accordingly, the overproduction of hydrogen peroxide, nitric oxide and other free radicals allowed reactive oxygen species (ROS)-mediated tumor cells death, as monitored by reduction in the synthesis of protein and nucleic acids.

Synthesis of new quinoline derivatives as inhibitors of human tumor cells growth.

A series of new 8‐[(2H‐tetrazol‐5‐yl)methoxy]quinoline derivatives, their sugar hydrazones, and their N‐glycoside derivatives were synthesized. Furthermore, the 1,2,4‐triazole‐3‐one derivatives 3 and 4 were synthesized from the amidrazone derivative 2. Some of the newly prepared compounds demonstrated inhibitory effects on the growth of MCF‐7 human breast cancer cells as compared with the activity of the commonly used anticancer drug, cisplatin. The results of antitumor evaluation revealed that compounds 2–5, 8b, and 12 inhibited the growth of cancer cells through their effect as free‐radical regulators by increasing the activity of superoxide dismutase and depletion of intracellular levels of reduced glutathione, catalase and glutathione peroxidase activities, accompanied with a high production of hydrogen peroxide, nitric oxide, and other free radicals causing the killing of tumor cells. The results suggested that the prepared compounds possess significant anticancer activity comparable to cisplatin and the antitumor activity of these prepared compounds was accompanied with a reduction in the levels of protein and nucleic acids.

Synthesis and docking studies of novel antitumor benzimidazoles

In this work, the benzimidazole-pyrrole conjugates 6a-h and benzimidazole-tetracycles conjugates 12-14 were prepared. The cytotoxicity of the compounds 3, 4a-h, 6a-h, 8, 10 and 12-14 was tested against lung cancer cell line A549. Compound 6b exhibited higher activity than the bis-benzoxazole natural product (UK-1), the standard. The tested 4g,h, 6a-h, 10 and 12-14 exhibited remarkable cytotoxicity activity against breast cancer cell line MCF-7 with higher activity than tamoxifen. Furthermore, compound 4h was found to be also more potent than doxurubicin. The antitumor promotion activity of synthesized compounds 4g,h, 6a-h, 10 and 12-14 has been estimated by studying their possible inhibitory effects on EBV-EA activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Among the studied compounds, the inhibitory activities of compounds 8, 13 and 14 demonstrated strong inhibitory effects on the Epstein-Barr virus early antigen (EBV-EA) activation without showing any cytotoxicity on the Raji cells and their effects being stronger than that of a representative control, oleanolic acid. Moreover, the molecular docking of the new compounds into plasminogen activator (uPA) receptor has been in correlation with the antitumor activity. All synthesized compounds 3, 4a-h, 6a-h, 8, 10 and 12-14 were docked into same groove of the binding site of the native co-crystalized (4-iodobenzo[b]thiophene-2-carboxamidine) ligand (PDB code:1c5x) for activity explaination. Compounds 4h, 6b and 13, giving the best docking results, were further studied to estimate their effect on the level of uPA using AssayMax human urokinase (uPA) ELISA kit. In case of A549 cell line, compound 6 exhibited similar activity to MMC, and for MCF-7 cell line, compound 4h exhibited similar activity to doxorubicin, in inhibiting the expression of uPA.

1-Piperazinylphthalazines as potential VEGFR-2 inhibitors and anticancer agents: Synthesis and in vitro biological evaluation

In our endeavor towards the development of effective VEGFR-2 inhibitors, three novel series of phthalazine derivatives based on 1-piperazinyl-4-arylphthalazine scaffold were synthesized. All the newly prepared phthalazines 16a-k, 18a-e and 21a-g were evaluated in vitro for their inhibitory activity against VEGFR-2. In particular, compounds 16k and 21d potently inhibited VEGFR-2 at sub-micromolar IC50 values 0.35 ± 0.03 and 0.40 ± 0.04 μM, respectively. Moreover, seventeen selected compounds 16c-e, 16g, 16h, 16j, 16k, 18c-e and 21a-g were evaluated for their in vitro anticancer activity according to US-NCI protocol, where compounds 16k and 21d proved to be the most potent anticancer agents. While, compound 16k exhibited potent broad spectrum anticancer activity with full panel GI50 (MG-MID) value of 3.62 μM, compound 21d showed high selectivity toward leukemia and prostate cancer subpanels [subpanel GI50 (MG-MID) 3.51 and 5.15 μM, respectively]. Molecular docking of compounds16k and 21d into VEGFR-2 active site was performed to explore their potential binding mode.

Increasing the binding affinity of VEGFR-2 inhibitors by extending their hydrophobic interaction with the active site: Design, synthesis and biological evaluation of 1-substituted-4-(4-methoxybenzyl)phthalazine derivatives

A series of anilinophthalazine derivatives 4a-j was initially synthesized and tested for its VEGFR-2 inhibitory activity where it showed promising activity (IC50 = 0.636-5.76 μM). Molecular docking studies guidance was used to improve the binding affinity for series 4a-j towards VEGFR-2 active site. This improvement was achieved by increasing the hydrophobic interaction with the hydrophobic back pocket of the VEGFR-2 active site lined with the hydrophobic side chains of Ile888, Leu889, Ile892, Val898, Val899, Leu1019 and Ile1044. Increasing the hydrophobic interaction was accomplished by extending the anilinophthalazine scaffold with a substituted phenyl moiety through an uriedo linker which should give this extension the flexibility required to accommodate itself deeply into the hydrophobic back pocket. As planned, the designed uriedo-anilinophthalazines 7a-i showed superior binding affinity than their anilinophthalazine parents (IC50 = 0.083-0.473 μM). In particular, compounds 7g-i showed IC50 of 0.086, 0.083 and 0.086 μM, respectively, which are better than that of the reference drug sorafenib (IC50 = 0.09 μM).

Design, synthesis and molecular docking study of novel quinoxalin-2(1H)-ones as anti-tumor active agents with inhibition of tyrosine kinase receptor and studying their cyclooxygenase-2 activity

On continuation to our work, new quinoxalin-2(1H)-ones were synthesized to study their cytotoxic effect against HepG-2 and MCF-7 with their effect on the human tyrosine kinase (TRK). Compounds 12, 18, 15, 13, 11a, 20 and 16, respectively, were found to be more potent than cisplatin against HepG2 and selective to TRK. Also, compounds 12, 18, 20, 13, 14, and 22, respectively, exhibited decidedly activity against MCF-7 and selectivity against human TRK compared to cisplatin. A molecular docking study was also performed to gain comprehensive understanding into plausible binding modes and to conclude the structure activity relationships of the synthesized compounds. Moreover, anti-inflammatory activity was studied. Compounds 12, 15, 18 and 22 were found to be potent and selective against COX-2.

Design, synthesis and structure-activity relationship of novel quinoxaline derivatives as cancer chemopreventive agent by inhibition of tyrosine kinase receptor.

The cancer chemopreventive activity of quinoxaline derivatives 1-20 has been evaluated by studying the inhibitory effect on Epstein-Barr virus early antigen (EBV-EA) activation. The quinoxaline derivatives 1-20 showed inhibitory effect on EBV-EA activation without cytotoxicity on Raji cells. All compounds exhibited dose dependent inhibitory activities, most of them showed significant activity at 1000 mol ratio/12-O-tetradecanoylphorbol-13-acetate (TPA). Compounds 7 and 9 exhibited stronger inhibitory effects on the EBV-EA activation than that of the representative control, oleanolic acid, at the highest measured concentration. In addition, compounds 7-10 showed potent and selective inhibition of human tyrosine kinase (TRK) in liver cancer HepG2 and breast cancer MCF-7 cell lines similar to the positive control, doxorubicin.

Part I. Synthesis, biological evaluation and docking studies of new 2-furylbenzimidazoles as antiangiogenic agents.

2-(2-Furyl)-1H-benzimidazoles 3-11 were synthesized and tested for their in vitro VEGF inhibition in MCF-7 cancer cell line. Compound 5a was more potent than Tamoxifen, and compounds 3b, 5a, 5c, 6b, 7a and 10 showed promising potency. Furthermore, compounds (6b, 7a and 10) showed remarkable selective inhibition of COX-2 enzyme close to that of Celecoxcib. Additionally, docking studies were performed using AutoDock 4.2 into the VEGFR2 kinase. Significant correlation exists between the biological activity (IC50 and %VEGF inhibition) against MCF-7 cell line and the molecular docking results (Ki and ΔGb) with correlation coefficients (R(2)) of 0.5513 and 0.4623 respectively. Accordingly, most of the synthesized 2-(2-furyl)-1H-benzimidazoles showed strong antiangiogenic activity against VEGFR2 kinase.