Rabah A.T. Serya

Design, synthesis, 3D pharmacophore, QSAR, and docking studies of carboxylic acid derivatives as Histone Deacetylase inhibitors and cytotoxic agents

In this study, five series of (E)-6-(4-substituted phenyl)-4-oxohex-5-enoic acids IIb-f (E), (E)-3-(4-(substituted)-phenyl)acrylic acids IIIa-g (E), 4-(4-(substituted)phenylamino)-4-oxobutanoic acids VIa,b,e, 5-(4-(substituted)phenylamino)-5-oxopentanoic acids VIIa,f and 2-[(4-(substituted)phenyl) carbamoyl]benzoic acids VIIIa,e were designed and synthesized. Selected compounds were screened in vitro for their cytotoxic effect on 60 human NCI tumor cell lines. Compound IIf (E) displayed significant inhibitory activity against NCI Non-Small Cell Lung A549/ATCC Cancer cell line (68% inhibition) and NCI-H460 Cancer cell line (66% inhibition). Moreover, the final compounds were evaluated in vitro for their cytotoxic activity on HepG2 Cancer cell line in which histone deacetylase (HDAC) is overexpressed. Compounds IIc (E), IIf (E), IIIb (E), and IIIg (E) exhibited the highest cytotoxic activity against HepG2 human cancer cell lines with IC50 ranging from 2.27 to 10.71μM. In addition, selected compounds were tested on histone deacetylase isoforms (HDAC1-11). Molecular docking simulation was also carried out for HDLP enzyme to investigate their HDAC binding affinity. In addition, generation of 3D-pharmacophore model and quantitative structure activity relationship (QSAR) models were combined to explore the structural requirements controlling the observed cytotoxic properties.

Discovery of Potent VEGFR-2 Inhibitors based on Furopyrimidine and Thienopyrimidne Scaffolds as Cancer Targeting Agents

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenesis. In this study, a series of novel furo[2,3-d]pyrimidine and thieno[2,3-d]pyrimidine based-derivatives were designed and synthesized as VEGFR-2 inhibitors, in accordance to the structure activity relationship (SAR) studies of known type II VEGFR-2 inhibitors. The synthesized compounds were evaluated for their ability to in vitro inhibit VEGFR-2 kinase enzyme. Seven compounds (15b, 16c, 16e, 21a, 21b, 21c and 21e) demonstrated highly potent dose-related VEGFR-2 inhibition with IC50 values in nanomolar range, of which the thieno[2,3-d]pyrimidine based-derivatives (21b, 21c and 21e) exhibited IC50 values of 33.4, 47.0 and 21 nM respectively. Moreover, furo[2,3-d]pyrimidine-based derivative (15b) showed the strongest inhibition of human umbilical vein endothelial cells (HUVEC) proliferation with 99.5% inhibition at 10 μM concentration. Consistent with our in vitro findings, compounds (21b and 21e) orally administered at 5 and 10 mg/kg/day for 8 consecutive days demonstrated potent anticancer activity in Erhlich ascites carcinoma (EAC) solid tumor murine model. Such compounds blunted angiogenesis in EAC as evidenced by reduced percent microvessel via decreasing VEGFR-2 phosphorylation with subsequent induction of apoptotic machinery. Furthermore, Miles vascular permeability assay confirmed their antiangiogenic effects in vivo. Intriguingly, such compounds showed no obvious toxicity.

Click and Release: SO2 Prodrugs with Tunable Release Rates

Employing an intramolecular cycloaddition reaction, we have developed a series of SO2 prodrugs with tunable release rates with half-lives ranging from minutes to days.

Pyridazine Based Scaffolds as Privileged Structures in anti-Cancer Therapy

Pyridazines, their oxo derivatives; pyridazinone as well as fused bi- or tricyclic pyridazine containing scaffolds are key structural features of many biologically active compounds with diverse pharmacological applications, including cancer therapy. Since protein kinases play prominent role in tumor biology, the inhibition of its signaling pathway is considered an effective therapeutic option for the treatment of cancer.Based on the various advantages of pyridazines in drug design including modulation of the physico-chemical properties, improving ADME and toxicity profile as well as easy and diverse synthetic methods of access, makes them an invaluable tool for designing compounds as future drugs for targeted cancer treatment.In this review, we have compiled and discussed the anticancer potential of pyridazine based scaffold, with special focus on those targeting protein kinase inhibition.

Rational design, synthesis and 2D-QSAR studies of antiproliferative tropane-based compounds

3,4-Diaryl-11-methyl-7-[(aryl)methylidene]-4,5,11-triazatricyclo[6.2.1.0*2,6*]undec-5-enes 14a–s were synthesized through reaction of 2,4-bis[(aryl)methylidene]-8-methyl-8-azabicyclo[3.2.1]octan-3-ones 12a–f with aryl hydrazines in the presence of catalytic amount of thiamine hydrochloride. Meanwhile, the 4-acetyl analogs 16a,b were obtained through reaction of 12b,e and hydrazine hydrate in acetic acid. Good support for the structure was received from single crystal X-ray studies of 14a. Some of the synthesized tropane containing-compounds showed promising antitumor properties during the in vitro MTT bio-assay against HepG2 (hepatocellular) and MCF7 (breast) human tumor carcinoma cell lines, with potency higher than that of doxorubicin (DNA intercalating agent, standard reference). Statistically significant 2D-QSAR model describes the antitumor properties against MCF7.

Design, Synthesis and Biological Evaluation of Novel Quinazoline-Based Anti-inflammatory Agents Acting as PDE4B Inhibitors

A novel series of quinzoline based compounds (IIIa-d, VIa-f, IXa-f) were designed, synthesized and screened for their inhibitory activity towards the PDE4B isoform. The in vivo anti-inflammatory effect of the titled compounds (IIIa-d, VIa-f, IXa-f) as well as their effect on the level of tumor necrosis factor (TNF-α) were evaluated. Among all of the synthesized compounds, IXb, IXd and IXf, exhibited good inhibitory activity against PDE4B enzyme with inhibition percentages of 42, 62 and 68%, respectively. Most of the tested compounds showed potent anti-inflammatory activity compared to indomethacin with a marked decrease in TNF-α level. The ulcerogenic effect of the tested compounds was also examined. The gastric mucosa of the tested animals remained intact after oral administration of the hit compounds. Additionally, docking study was used to explore the possible binding mode of the active compounds on the PDE4B enzyme as well as to illustrate the selectivity of the active hits on the PDE4B isoform.

Design, synthesis and biological evaluation of indazole–pyrimidine based derivatives as anticancer agents with anti-angiogenic and antiproliferative activities

Three series of novel indazole–pyrimidine based compounds were designed, synthesized and biologically evaluated as VEGFR-2 kinase inhibitors. The most active compound 6i (IC50 = 24.5 nM) was further evaluated against a HUVEC cell line showing an IC50 of 1.37 μM. Moreover, it showed an indirect anti-angiogenic effect through the suppression of secretion of VEGF and TGF-b1 from prostate cancer cells. Five compounds were selected by the NCI for evaluation of their in vitro anticancer activity against the full NCI panel of cell lines at 10 μM. Compounds 6e and 6f were further selected for 5-dose testing. Compound 6e exerted nanomolar GI50 values against several cell lines: CCRF-CEM (901 nM), MOLT-4 (525 nM) and CAKI-1 (992 nM) and one digit micromolar activity against the rest of the cell lines ranging from 1.05 μM to 2.41 μM. Compound 6f showed one digit micromolar activity against the whole panel of cell lines ranging from 1.55 μM to 7.4 μM. A molecular docking study was employed to investigate the predicted binding mode of the target compounds with VEGFR-2, using Autodock software. Furthermore, MD simulation was implemented for compounds 6i and 10c for further validation and rationalization of their binding mode.

Fragment‐Based Drug Discovery in the Bromodomain and Extra‐Terminal Domain Family

Bromodomain and extra‐terminal domain (BET) inhibition has emerged recently as a potential therapeutic target for the treatment of many human disorders such as atherosclerosis, inflammatory disorders, chronic obstructive pulmonary disease (COPD), some viral infections, and cancer. Since the discovery of the two potent inhibitors, I‐BET762 and JQ1, different research groups have used different techniques to develop novel potent and selective inhibitors. In this review, we will be concerned with the trials that used fragment‐based drug discovery (FBDD) approaches to discover or optimize BET inhibitors, also showing fragments that can be further optimized in future projects to reach novel potent BET inhibitors.

Synthesis and in vitro antiproliferative activity of novel pyrazolo[3,4-d]pyrimidine derivatives

A novel series of pyrazolo[3,4-d]pyrimidine derivatives were designed, synthesized and evaluated for their antiproliferative activity. Among the five compounds selected by NCI, compound 11a showed a distinctive pattern of selectivity on cell line panels and was further screened for a 5-log dose range, where it showed potent antiproliferative activity with median growth inhibition (GI50) equal to 1.71 μM against the CNS cancer SNB-75 cell line. The tested derivative showed remarkably the highest cell growth inhibition against non-small cell lung cancer HOP-62, CNS cancer SNB-75, breast cancer HS578T, and melanoma MALME-3M cell lines. Flow cytometric analysis revealed that compound 11a could significantly induce apoptosis in A549 cells in vitro at low micromolar concentrations. Further investigation showed that compound 11a induced significant cell cycle arrest at G0/G1 phase partly due to its ability to downregulate cyclin D1 and upregulate p27kip1 levels.

Development of Potent Adenosine Monophosphate Activated Protein Kinase (AMPK) Activators

Previously, we reported the identification of a thiazolidinedione‐based adenosine monophosphate activated protein kinase (AMPK) activator, compound 1 (N‐[4‐({3‐[(1‐methylcyclohexyl)methyl]‐2,4‐dioxothiazolidin‐5‐ylidene}methyl)phenyl]‐4‐nitro‐3‐(trifluoromethyl)benzenesulfonamide), which provided a proof of concept to delineate the intricate role of AMPK in regulating oncogenic signaling pathways associated with cell proliferation and epithelial–mesenchymal transition (EMT) in cancer cells. In this study, we used 1 as a scaffold to conduct lead optimization, which generated a series of derivatives. Analysis of the antiproliferative and AMPK‐activating activities of individual derivatives revealed a distinct structure–activity relationship and identified 59 (N‐(3‐nitrophenyl)‐N′‐{4‐[(3‐{[3,5‐bis(trifluoromethyl)phenyl]methyl}‐2,4‐dioxothiazolidin‐5‐ylidene)methyl]phenyl}urea) as the optimal agent. Relative to 1, compound 59 exhibits multifold higher potency in upregulating AMPK phosphorylation in various cell lines irrespective of their liver kinase B1 (LKB1) functional status, accompanied by parallel changes in the phosphorylation/expression levels of p70S6K, Akt, Foxo3a, and EMT‐associated markers. Consistent with its predicted activity against tumors with activated Akt status, orally administered 59 was efficacious in suppressing the growth of phosphatase and tensin homologue (PTEN)‐null PC‐3 xenograft tumors in nude mice. Together, these findings suggest that 59 has clinical value in therapeutic strategies for PTEN‐negative cancer and warrants continued investigation in this regard.