Elbatrawy, A. A., S. J. Hyeon, N. Yue, E. E. A. Osman, S. H. Choi, S. Lim, Y. Kim, H. Ryu, M. Cui, and G. Nam, ""Turn-On" Quinoline-Based Fluorescent Probe for Selective Imaging of Tau Aggregates in Alzheimer's Disease: Rational Design, Synthesis, and Molecular Docking.", ACS sensors, vol. 6, issue 6, pp. 2281-2289, 2021. Abstract

Tau aggregation is believed to have a strong association with the level of cognitive deficits in Alzheimer's disease (AD). Thus, optical brain imaging of tau aggregates has recently gained substantial attention as a promising tool for the early diagnosis of AD. However, selective imaging of tau aggregates is a major challenge due to sharing similar β-sheet structures with homologous Aβ fibrils. Herein, four quinoline-based fluorescent probes (Q-tau) were judiciously designed using the donor-acceptor architecture for selective imaging of tau aggregates. In particular, probe Q-tau 4 exhibited a strong intramolecular charge transfer and favorable photophysical profile, such as a large Stokes' shift and fluorescence emission wavelength of 630 nm in the presence of tau aggregates. The probe also displayed a "turn-on" fluorescence behavior toward tau fibrils with a 3.5-fold selectivity Aβ fibrils. In addition, Q-tau 4 exhibited nanomolar binding affinity to tau aggregates ( = 16.6 nM), which was 1.4 times higher than that for Aβ fibrils. The mechanism of "turn-on" fluorescence was proposed to be an environment-sensitive molecular rotor-like response. Moreover, labeling of human AD brain sections demonstrated favorable colocalization of Q-tau 4 and the phosphorylated tau antibody, while comparable limited staining was observed with Aβ fibrils. Molecular docking was conducted to obtain insights into the tau-binding mode of the probe. Collectively, Q-tau 4 has successfully been used as a tau-specific fluorescent imaging agent with lower background interference.

Osman, E. E. A., A. Rehemtulla, and N. Neamati, "Why All the Fury over Furin?", Journal of medicinal chemistry, 2021. Abstract

Analysis of the SARS-CoV-2 sequence revealed a multibasic furin cleavage site at the S1/S2 boundary of the spike protein distinguishing this virus from SARS-CoV. Furin, the best-characterized member of the mammalian proprotein convertases, is an ubiquitously expressed single pass type 1 transmembrane protein. Cleavage of SARS-CoV-2 spike protein by furin promotes viral entry into lung cells. While furin knockout is embryonically lethal, its knockout in differentiated somatic cells is not, thus furin provides an exciting therapeutic target for viral pathogens including SARS-CoV-2 and bacterial infections. Several peptide-based and small-molecule inhibitors of furin have been recently reported, and select cocrystal structures have been solved, paving the way for further optimization and selection of clinical candidates. This perspective highlights furin structure, substrates, recent inhibitors, and crystal structures with emphasis on furin's role in SARS-CoV-2 infection, where the current data strongly suggest its inhibition as a promising therapeutic intervention for SARS-CoV-2.

Abd El-Mageed, M. M. A., A. A. M. Eissa, A. E. - S. Farag, and E. E. A. Osman, "Design and synthesis of novel furan, furo[2,3-d]pyrimidine and furo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives as potential VEGFR-2 inhibitors.", Bioorganic chemistry, vol. 116, pp. 105336, 2021. Abstract

Novel furan 6a-c, furo[2,3-d]pyrimidine 7a-f, 9, 10a-f, 12a,b, 14a-d and furo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine 8a-f derivatives were designed based on their structural similarity to a previously described oxazole VEGFR-2 back pocket binding fragment. The designed compounds were synthesized and screened for their in vitro VEGFR-2 inhibitory activity where they exhibited good to moderate nanomolar inhibition with improved ligand efficiencies. 8b and 10c (IC = 38.72 ± 1.7 and 41.40 ± 1.8 nM, respectively) were equipotent to sorafenib and 6a, 6c, 7f, 8a, 8c, 10b, 10f, 12b, 14c and 14d showed good activity (IC = 43.31-98.31 nM). The furotriazolopyrimidines 8a-c and furopyrimidine derivative 10c were further evaluated for their in vitro antiproliferative activity against human umbilical vein endothelial cells (HUVECs) where 8b showed higher potency than sorafenib and resulted in cell cycle arrest at G2/M phase whereas 8c revealed good antiproliferative activity with cell cycle arrest at G1 phase. Moreover, 8a-c and 10c showed significant inhibitory effects on the invasion and migration of HUVECs. Molecular docking study was conducted to gain insight about the potential binding mode. The furo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives 8b and 8c represent interesting starting point for antiangiogenic compounds based on their activity and favorable drug likeness profiles.

Osman, E. E. A., N. S. Hanafy, R. F. George, and S. M. El-Moghazy, "Design and synthesis of some barbituric and 1,3-dimethylbarbituric acid derivatives: A non-classical scaffold for potential PARP1 inhibitors.", Bioorganic chemistry, vol. 104, pp. 104198, 2020. Abstract

Six series based on barbituric acid 5a-e, 10a-d; thiobarbituric acid 6a-e, 11a-d and 1,3-dimethylbarbituric acid 7a-e, 12a-d were prepared and screened for their in vitro PARP1 inhibition. They revealed promising inhibition at nanomolar level especially compounds 5c, 7b, 7d and 7e (IC = 30.51, 41.60, 41.53 and 36.33 nM) with higher potency than olaparib (IC = 43.59 nM). Moreover, compounds 5b, 5d, 7a, 12a and 12c exhibited good comparable activity (IC = 65.93, 58.90, 66.57, 45.40 and 50.62 nM, respectively). Furthermore, the most active compounds 5c, 7b, 7d, 7e, 12a and 12c against PARP1 in vitro were evaluated in the BRCA1 mutated triple negative breast cancer cell line MDA-MB-436 where 5c and 12c showed higher potency compared to olaparib and result in cell cycle arrest at G2/M phase. 5c and 12c showed apoptotic effects in MDA-MB-436 and potentiated the cytotoxicity of temozolomide in A549 human lung epithelial cancer cell line. Compounds 5c and 12c represent interesting starting points towards PARP1 inhibitors.

Osman, E. E. A., P. L. Toogood, and N. Neamati, "COVID-19: Living through Another Pandemic.", ACS infectious diseases, vol. 6, issue 7, pp. 1548-1552, 2020. Abstract

Novel beta-coronavirus SARS-CoV-2 is the pathogenic agent responsible for coronavirus disease-2019 (COVID-19), a globally pandemic infectious disease. Due to its high virulence and the absence of immunity among the general population, SARS-CoV-2 has quickly spread to all countries. This pandemic highlights the urgent unmet need to expand and focus our research tools on what are considered "neglected infectious diseases" and to prepare for future inevitable pandemics. This global emergency has generated unprecedented momentum and scientific efforts around the globe unifying scientists from academia, government and the pharmaceutical industry to accelerate the discovery of vaccines and treatments. Herein, we shed light on the virus structure and life cycle and the potential therapeutic targets in SARS-CoV-2 and briefly refer to both active and passive immunization modalities, drug repurposing focused on speed to market, and novel agents against specific viral targets as therapeutic interventions for COVID-19.

Abd-Allah, W. H., E. E. A. Osman, M. A. - E. - M. Anwar, H. N. Attia, and S. M. El Moghazy, Design, synthesis and docking studies of novel benzopyrone derivatives as anticonvulsants, , vol. 98, pp. 103738, 2020. AbstractWebsite

A series of coumarin derivatives 6–8, 9a-h, 11 and 13a, b -16a, b was synthesized and screened for their anticonvulsant profile. Screening of these analogues using the 'gold standard methods' revealed variable anticonvulsant potential with remarkable effects observed particularly in chemically-induced seizure test. Compounds 6, 7, 13b disclosed the highest potency among the series with 100% protection against scPTZ. Quantification study confirmed that compound 6 (ED50 0.238 mmol/kg) was the most active congener in the scPTZ model and was approximately 1.5 folds more potent than ethosuximide as reference drug Meanwhile, in the MES test, candidate drugs exhibited mild to moderate anticonvulsant efficacy, the highest of which was compound 14a, imparting 50% protection at 2.1 mmol/kg, followed by other compounds with activity ranging from 14 to 33%, as compared to diphenylhydantoin. Additionally, all candidate compounds were screened for acute neurotoxicity using the rotarod method to identify motor impairment, where almost all compounds passed the test. Further neurochemical investigation was performed to unravel the effect of the most active compound (6) on GABA level in mouse brain, where a significant elevation was evident by 4 and 1.4 folds with respect to that of the control and reference groups at p < 0.05. Molecular modeling study using Discovery Studio program was performed, where compound 6 exhibited good binding interaction with γ-aminobutyric acid aminotransferase (GABA-AT) enzyme and this was consistent with the attained experimental results.

Youssif, B. G. M., A. M. Mohamed, E. E. A. Osman, O. F. Abou-Ghadir, D. H. Elnaggar, M. H. Abdelrahman, L. Treamblu, and H. A. M. Gomaa, 5-Chlorobenzofuran-2-carboxamides: From allosteric CB1 modulators to potential apoptotic antitumor agents, , vol. 177, pp. 1 - 11, 2019. AbstractWebsite

Cannabinoids as THC and the CB1 allosteric modulator CBD were reported to have antiproliferative activities with no reports for other CB1 allosteric modulators as the 5-chloroindole-2-carboxamide derivatives and their furan congeners. Based on the antiproliferative activity of two 5-chlorobenzofuran-2-carboxamide allosteric CB1 modulators, a series of novel derivatives was designed and synthesized. The synthesized compounds were tested in a cell viability assay using human mammary gland epithelial cell line (MCF-10A) where all the compounds exhibited no cytotoxic effects and more than 85% cell viability at a concentration of 50 μM. Some derivatives showed good antiproliferative activities against tumor cells as compounds 8, 15, 21 and 22. The most active compound 15 showed equipotent activity to doxorubicin. Compounds 7, 9, 15, 16, 21 and 22 increased the level of active caspase 3 by 4–8 folds, compared to the control cells in MCF-7 cell line and doxorubicin as a reference drug. Compounds 15 and 21, the most activecaspase-3 inducers, increase the levels of caspase 8 and 9 indicating activation of both intrinsic and extrinsic pathways and showed potent induction of Bax, down-regulation of Bcl-2 protein levels and over-expression of Cytochrome C levels in MCF-7 cell lines. Compound 15 exhibited cell cycle arrest at the Pre-G1 and G2/M phases in the cell cycle analysis of MCF-7 cell line. The drug Likeness profile of the synthesized compounds showed that all the compounds were predicted to have high oral absorption complying with different pharmacokinetics filters.

Hisham, M., B. G. M. Youssif, E. E. A. Osman, A. M. Hayallah, and M. A. El-Aziz, Synthesis and biological evaluation of novel xanthine derivatives as potential apoptotic antitumor agents, , vol. 176, pp. 117 - 128, 2019. AbstractWebsite

A series of novel xanthine/NO donor hybrids containing 1,3,8-trisubstituted or 1,8-disubstituted xanthine derivatives were designed and synthesized. The synthesized compounds were tested in a cell viability assay using human mammary gland epithelial cell line (MCF-10A) where all the compounds exhibited no cytotoxic effects and more than 90% cell viability at a concentration of 50 μM. The oxime containing compounds 7a-b and 17-24 were more active as antiproliferative agents than their non-oxime congeners 6a-b and 9-16. Hydroxyimino-phenethyl scaffold compounds 17-24 were more active than the hydroxyimino-ethyl phenyl acetamide 7a-b derivatives. Compounds 18–20 and 22-24 exhibited inhibition of EGFR with IC50 ranging from 0.32 to 2.88 μM. Compounds 18-20 and 22-24 increased the level of active caspase 3 by 4–8 folds, compared to the control cells in Panc-1 cell lines compared to doxorubicin as a reference drug. Compounds 18, 22 and 23 were the most caspase-3 inducers. Compounds 22 and 23 increased the levels of caspase-8 and 9 indicating activation of both intrinsic and extrinsic pathways and showed potent induction of Bax, down-regulation of Bcl-2 protein levels and over-expression of cytochrome c levels in Panc-1 human pancreas cancer cells. Compound 23 exhibited mainly cell cycle arrest at the Pre-G1 and G2/M phases in the cell cycle analysis of Panc-1 cell line. The drug likeness profiles of compounds 18-20 and 22-24 were predicted to have good to excellent drug likeness profiles specially compounds 18-20 and 23. Finally molecular docking study was performed at the EGFR active site to suggest thier possible binding mode. The hydroxyimino-phenethyl scaffold compounds 17-24 represent an interesting starting point to optimize their pharmacokinetics and pharmacodynamics profiles.

Moussa, S. A., E. E. A. Osman, N. M. Eid, S. M. Abou-Seri, and S. M. El Moghazy, "Design and synthesis of novel 5-(4-chlorophenyl)furan derivatives with inhibitory activity on tubulin polymerization.", Future medicinal chemistry, vol. 10, issue 16, pp. 1907-1924, 2018 Aug 01. Abstract

AIM: Discovery of novel series of colchicine binding site inhibitors (CBSIs).

MATERIALS & METHODS: Isoxazoline 3a-d, pyrazoline 4a-b, 7a-f and 8a-f, cyclohexenone 9a-b and 10a-b or pyridine derivatives 11a-b were synthesized and evaluated for their inhibition of tubulin polymerization and cytotoxicity. Most of the compounds displayed potent to moderate antitumor activity against leukemia SR cell line.7c, 7e and 11a were more potent than colchicine with IC of 0.09, 0.05 and 0.06 μM, and percentage inhibition in tubulin polymerization of 95.2, 96.0 and 96.3%, respectively. Compounds 7c and 11a showed cell-cycle arrest at G2/M phase and induced apoptosis and were able to bind the colchicine binding site of tubulin with comparable affinity to colchicine. Docking study showed that these compounds may interact with tubulin exploiting a binding cavity not commonly reported in the binding of CBSI.

CONCLUSION: Compounds 7c and 11a may be considered as promising CBSI based on their excellent activity and favorable drug likeness profile.

Nowar, R. M., E. E. A. Osman, S. M. Abou-Seri, S. M. El Moghazy, and D. A. Abou El Ella, "Design, synthesis and biological evaluation of some novel quinazolinone derivatives as potent apoptotic inducers.", Future medicinal chemistry, vol. 10, issue 10, pp. 1191-1205, 2018 May 01. Abstract

AIM: Novel quinazolinone and triazinoquinazolinone derivatives were designed and synthesized as apoptotic inducers.

METHODOLOGY/RESULTS: Most of the synthesized compounds showed excellent antiproliferative activity against MCF-7 and HCT-116 cell lines, respectively. Compounds 7a, 8a, 8d, 14a and 14d were superior to doxorubicin as activators of caspases 3, 8 and 9 in HCT-116 cell line. The most potent caspase inducers, 8d and 14a showed cell cycle arrest mainly in G1 and S phase, respectively and increased the levels of p53, Bax and the Bax/Bcl-2 ratio compared with doxorubicin in HCT-116 cells with excellent selectivity against CCD-18Co human colon normal cell line.

CONCLUSION: The synthesized compounds can be considered as potent apoptotic inducers interfering with extrinsic and intrinsic apoptotic pathways.

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