Design, synthesis, and antitumor efficacy of novel 5-deazaflavin derivatives backed by kinase screening, docking, and ADME studies

Novel 5-deazaflavins were designed as potential anticancer candidates. Compounds 4j, 4k, 5b, 5i, and 9f demonstrated high cytotoxicity against MCF-7 cell line with IC₅₀ of 0.5-190nM. Compounds 8c and 9g showed preferential activity against Hela cells (IC₅₀: 1.69 and 1.52 μM respectively). However, compound 5d showed notable potency against MCF-7 and Hela cell lines of 0.1 nM and 1.26 μM respectively. Kinase profiling for 4e showed the highest inhibition against a 20 kinase panel. Additionally, ADME prediction studies exhibited that compounds 4j, 5d, 5f, and 9f have drug-likeness criteria to be considered promising antitumor agents deserving of further investigation. SAR study showed that substitutions with 2-benzylidene hydra zino have a better fitting into PTK with enhanced antiproliferative potency. Noteworthy, the incorporation of hydrazino or ethanolamine moieties at position 2 along with small alkyl or phenyl at N-10, respectively revealed an extraordinary potency against MCF-7 cells with IC₅₀ values in the nanomolar range.

In-use stability assessment of FDA approved metformin immediate release and extended release products for N-Nitrosodimethylamine and dissolution quality attributes

Metformin is a widely used first-line oral antidiabetic agent. TheFood and Drug Administration (FDA) confirmed the presence of the ofN-nitrosodimethylamine (NDMA) impurity, a carcinogenic, above the acceptable daily intake (ADI, 96 ng/day) in certain metformin products. The objective of the present study was to assess in-use stability of commercial metformin products for NDMA and dissolution quality attributes. Four immediate-release (M1-M4) and six extended-rerelease (M5-M10) metformin products were evaluated in the stability testing. All products were repacked in pharmacy vials and stored at 30 °C/75% RH for 12 weeks. Five products (M2, M3, M5, M7 and M10) had NDMA level above ADI limit (96 ng/day) before in-use stability exposure. NDMA in M2 (1164 ± 52.9 ng/tablet) and M3 (3776 ± 351.9 ng/tablet) products were 12 and 39 folds of ADI, respectively. Similarly, ER products, M5 (191 ± 94.1 ng/tablet), M7 (1473 ± 47.3 ng/tablet) and M10 (423 ± 55.8 ng/tablet) exhibited NDMA of 1.9, 15.3 and 4.4 folds of ADI, respectively. The impurity level significantly (p < 0.05) increased after 12-week stability exposure to 2.72, 2.47, 2.23 and 2.78 folds of initial values in M2, M3, M7 and M10. In summary, these findings suggested that carcinogenic impurity generation was affected by in-use stability condition exposure and it is expected that several more products currently in the market may also be recalled soon.

Antitumor and multikinase inhibition activities of some synthesized coumarin and benzofuran derivatives

Two new series of coumarin and benzofuran derivatives were designed, synthesized, and assessed for their in vitro and in vivo antitumor activities against breast cancer. Compounds 8, 9, 14, 15, and 17 exhibited the best antiproliferative activities (IC₅₀ : 0.07-2.94 μM) against the MCF-7 cell line, compared with lapatinib (IC₅₀ : 4.69 μM). Compound 14, with the most potent cytotoxic activity against MCF-7 cells, was capable of enhancing preG1 apoptosis and triggering cell cycle arrest at the G2/M phase. The kinase inhibitory activity of compound 14 against a panel of 22 kinases was examined to reveal multikinase inhibition within -39% to -97%. Furthermore, compound 14 exhibited potent in vivo Ehrlich (mammary adenocarcinoma) tumor regression, positive caspase-3, and negative EGFR immunoreaction, and was capable of elevating the catalase level. The physicochemical properties and pharmacokinetic parameters of compound 14 were investigated in silico for its druglikeness.

In-Situ Implant Formulation of Laurate and Myristate Prodrugs of Dolutegravir for Ultra-Long Delivery

The focus of present work was to synthesize prodrugs of dolutegravir (DTG) for ultra-long delivery purpose. The prodrug was synthesized by esterification of hydroxyl group with carboxyl group of fatty acid (lauric or myristic acid). The prodrugs were characterized by differential scanning calorimetry, X-ray powder diffraction, nuclear magnetic resonance, Fourier transformed infrared, near infrared-chemical imaging, pH-solubility, partition coefficient, and stability (solid and liquid). Stability studies were performed by exposing the powder drugs to 40°C/75% RH for three months and buffer solutions at room temperature for 72 h. The prodrugs and drug were formulated into in-situ implant using biodegradable polymer. Thermal, spectral, and diffractometric data indicated formation of new chemical and solid forms. Formation of prodrugs resulted in lowering of melting point of DTG from 191.1°C to 163.7 and 140.7°C for DTG-Laurate and DTG-Myristate prodrugs, respectively. A decrease in solubility of 18.2-115.9 and 124.5-1594.9 folds was observed for DTG-Laurate and DTG-Myristate, respectively compared to DTG. Similarly, the prodrugs were highly lipophilic compared to DTG. Solid-state and pH-stability profiles of DTG and prodrugs were comparable. Implant formulation released 60.1% in 77 days compared to 95.6% in 35 days in the case of DTG-Myristate and DTG, respectively. In summary, combining prodrug and drug delivery approaches can be utilized for delivering drug for ultra-long period.

Benzodiazepine-induced photosensitivity reactions: A compilation of cases from literature review with Naranjo causality assessment

OBJECTIVE

Benzodiazepines have been reported to cause photosensitivity reactions. We characterized the clinical presentation and diagnosis of benzodiazepine-associated photosensitivity and adjudicated these cases for a causal association with benzodiazepines.

METHODS

A literature search on PubMed's "MeSH" search feature and CINAHL (1964 to 2019) was performed using search terms: benzodiazepine, photosensitivity, and photosensitivity disorders/chemically induced. We applied the Naranjo scale, a standardized causality assessment algorithm, to identified cases.

RESULTS

We identified eight published cases, with 50% of patients being female with a mean age of 46.3 years. Alprazolam, tetrazepam, clobazam, and clorazepate induced phototoxic reactions. Chlordiazepoxide induced one photoallergic reaction. Photosensitivity occurred between 1-3 days (37.5%), 7-14 days (25%), and >14 days (25%). Photosensitivity resolved after drug discontinuation within 2 weeks (62.5%). Benzodiazepine rechallenge confirmed photosensitivity in 75% of cases. Photopatch testing was negative in two patients; however, these patients had positive oral provocation testing. However, an oral photoprovocation test, an ideal diagnostic test, was not administered to several patients. Despite these challenges, the Naranjo scale identified 5 cases as definite benzodiazepine-induced photosensitivity.

CONCLUSION

Five benzodiazepines induced photosensitivity reactions. Five patients showed a definite association with the Naranjo scale. Reporting to pharmacovigilance databases may help identify other benzodiazepines causing photosensitivity reactions.

HER2 Kinase-Targeted Breast Cancer Therapy: Design, Synthesis, and In Vitro and In Vivo Evaluation of Novel Lapatinib Congeners as Selective and Potent HER2 Inhibitors with Favorable Metabolic Stability

HER2 kinase as a well-established target for breast cancer (BC) therapy is associated with aggressive clinical outcomes; thus, herein we present structural optimization for HER2-selective targeting. HER2 profiling of the developed derivatives demonstrated potent and selective inhibitions (IC₅₀: 5.4-12 nM) compared to lapatinib (IC₅₀: 95.5 nM). Favorably, 17d exhibited minimum off-target kinase activation. NCI-5-dose screening revealed broad-spectrum activities (GI₅₀: 1.43-2.09 μM) and 17d had a remarkable selectivity toward BC. Our compounds revealed significant selective and potent antiproliferative activities (∼20-fold) against HER2+ (AU565, BT474) compared to HER2(-) cells. At 0.1 IC₅₀, 15i, 17d, and 25b inhibited pERK1/2 and pAkt by immunoblotting. Furthermore, 17d demonstrated potent in vivo tumor regression against the BT474 xenograft model. Notably, a metastasis case was observed in the vehicle but not in the test mice groups. CD-1 mice metabolic stability assay revealed high stability and low intrinsic clearance of 17d (T_1/2 > 145 min and CL_int(mic) < 9.6 mL/min/kg).

Dual Targeting of VEGFR2 and C-Met Kinases via the Design and Synthesis of Substituted 3-(Triazolo-thiadiazin-3-yl)indolin-2-one Derivatives as Angiogenesis Inhibitors

The vascular endothelial growth factor receptor 2 (VEGFR2) and c-mesenchymal epithelial transition factor (c-Met) are members of receptor tyrosine kinases which have a crucial role in the process of angiogenesis. Isatin moiety is a versatile group that is shared in many compounds targeting both c-Met and VEGFR2 kinases. In this study, we designed and synthesized different derivatives of substituted 3-(triazolo-thiadiazin-3-yl)indolin-2-one derivatives (6a-y) as dual inhibitors for c-Met and VEGFR2 enzymes. Eight compounds 6a, 6b, 6e, 6l, 6n, 6r, 6v, and 6y were assessed for their anticancer activities against a panel of 58 cancer cell lines according to the US-NCI protocol. Compound 6b revealed the most effective antiproliferative potency (GI %), with broad-spectrum activity against different subpanels of the most NCI 58 tumor cell lines. An in vivo hen's egg-chorioallantoic membrane (HET-CAM) angiogenic study was carried out for 21 compounds 6a, b, d, f, h, i, k-o, t, and 6x to check their mortality and toxicity. At 100 μM concentration, all compounds produced 100% mortality of the chick embryos. At 40 μM concentration, 13 compounds did not exhibit any detectable mortality (nontoxic) and revealed a potent antiangiogenic effect. Seven compounds 6b, 6d, 6f, 6n, 6o, 6t, and 6x significantly decreased the number of blood vessels, and compound 6b was the most effective antiangiogenic agent comparable to dexamethasone. Molecular docking studies were conducted for compound 6b to investigate its mode of interaction within the binding site of both c-Met and VEGFR2 kinases.

Abstract C029: Exosomes-associated miR-5001, miR-3692 and miR-4529 are novel biomarkers for aggressive prostate cancer and associated with poor prognosis in African American patients

Background: Although microRNA (miR) profiling has been widely used to predict clinical outcomes, differential miR expressions that can segregate prostate cancer (PCa) patients based on their races and tumor aggressiveness have not been fully investigated. We aimed to determine the diagnostic and prognostic abilities of exosomal miRs to identify the aggressive phenotypes of PCa in African American (AA) men.

Methods: Exosomes were isolated from blood of twenty AA and European Americans (EuA) PCa patients at low and high Gleason scores and their aged-matched healthy subjects (n=20) as well as AA and EuA normal and PCa cells. miR profiling was performed on PCa exosomes derived from blood and PCa cells. The expression level was correlated with clinical outcomes of PCa patients. The sensitivity and specificity of exosomal miRs were assessed using receiver operating characteristic (ROC) curve.

Results: Results from miR profiling showed a number of exosomal miRs that were able to differentiate normal from PCa, low from high Gleason scores and AA from EuA PCa patients. These dysregulated miRs were validated in another cohort of forty PCa patients in addition to a large panel of PCa cell lines. In the validation cohort, miR-5001, miR-3692 and miR-4529 were upregulated in the exosomes derived from blood of AA compared to EuA men. These miRs were correlated with age, T-stage, residual tumor, involvement of lymph nodes, Gleason score, and overall survival of AA patients. The combination of these miRs showed high discriminatory power (AUC=0.91) for segregation of PCa patients according to their clinical outcomes.

Conclusion: miR profiling identified a new set of miRs that can differentiate PCa specimens based on their race and Gleason score. The differential expression of these miRs demonstrates their potential role as biomarkers in the context of racial disparity. Further studies are warranted to determine their role in PCa at advanced stages.

Citation Format: Rofaida Gaballa, Mohamed Gaballah, Hamdy E.A. Ali, Andrew S. Sholl, Hamed I. Ali, Zakaria Y. Abd Elmageed. Exosomes-associated miR-5001, miR-3692 and miR-4529 are novel biomarkers for aggressive prostate cancer and associated with poor prognosis in African American patients [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C029.

Abstract B045: Exosomal microRNAs are associated with prostate cancer aggressiveness in African American patients

Background: The morbidity and mortality rates of prostate cancer (PCa) in African American (AA) are 2-3 times higher than European American (EuA) men. The molecular mechanisms underlying the aggressiveness of PCa have not fully identified. Thus, our aim was to evaluate the diagnostic/prognostic utility of exosomal microRNAs (miRs) to classify PCa patients according their race and aggressive phenotype in AA patients. Their functional role in tumor aggressiveness was also determined.

Methods: Exosomes were isolated from the conditioned media of AA and EuA PCa cell lines. The expression of miRs was validated in exosomes, free-circulating plasma, and FFPE tissue specimens of forty AA and EuA patients using quantitative real-time PCR analysis. The sensitivity and specificity of exosomal miRs to classify prostate cancer patients according their race and aggressiveness were assessed using receiver operating characteristic (ROC) curve analysis. To study the functional significance of exosomal miRs, cell proliferation, clonogenic, cell cycle and migration assays were performed in PCa cells transfected with miR-3128.

Results: Differential expression of exosomal miR-3613-3p, miR-3218, miR-3679, and miR-3680 was demonstrated in the plasma of AA versus EuA of PCa patients. While exosomal miR-3613 and miR-3679 (p&lt;0.05) were upregulated, free-circulating miRs downregulated (p&lt;0.05) in the plasma of AA versus EuA patients. The accuracy of miR-3679 to discriminate AA from EuA was improved when combined with the other three miRs (AUC jumped from 0.717 to 0.897). Intriguingly, miR-3128 showed a dual role in AA versus EuA cells. Overexpression of miR-3128 increased the cell growth in AA cells while it did the opposite in EuA cells. These data were recapitulated by migration, cell cycle and clonogenic assays.

Conclusion: Our findings underline the role of exosomal miRs in health disparity of PCa. The differential expression of miRs in AA men demonstrates their reliability as biomarkers and their potential role in promoting tumor aggressiveness in

AA men.

Citation Format: Hamdy E.A. Ali, Rofaida Gaballa, Andrew S. Sholl, Mohamed Gaballah, Juan J. Bustamante, Preeti Zanwar, Hamed I. Ali, Zakaria Y. Abd Elmageed. Exosomal microRNAs are associated with prostate cancer aggressiveness in African American patients [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B045.

Dysregulated gene expression predicts tumor aggressiveness in African-American prostate cancer patients

Molecular mechanisms underlying the health disparity of prostate cancer (PCa) have not been fully determined. In this study, we applied bioinformatic approach to identify and validate dysregulated genes associated with tumor aggressiveness in African American (AA) compared to Caucasian American (CA) men with PCa. We retrieved and analyzed microarray data from 619 PCa patients, 412 AA and 207 CA, and we validated these genes in tumor tissues and cell lines by Real-Time PCR, Western blot, immunocytochemistry (ICC) and immunohistochemistry (IHC) analyses. We identified 362 differentially expressed genes in AA men and involved in regulating signaling pathways associated with tumor aggressiveness. In PCa tissues and cells, NKX3.1, APPL2, TPD52, LTC4S, ALDH1A3 and AMD1 transcripts were significantly upregulated (p < 0.05) compared to normal cells. IHC confirmed the overexpression of TPD52 (p = 0.0098) and LTC4S (p < 0.0005) in AA compared to CA men. ICC and Western blot analyses additionally corroborated this observation in PCa cells. These findings suggest that dysregulation of transcripts in PCa may drive the disparity of PCa outcomes and provide new insights into development of new therapeutic agents against aggressive tumors. More studies are warranted to investigate the clinical significance of these dysregulated genes in promoting the oncogenic pathways in AA men.

Abstract B41: Transcriptome-wide profiling identifies novel differential genes associated with health disparity of prostate cancer

Background: The incidence and mortality rates of prostate cancer (PCa) are twice as high in African American (AA) than in Caucasian American (CA) men. The molecular alterations associated with this racial disparity have not been fully elucidated. We aim to compare the expression profile of AA and CA men using microarray available data and paraffin-embedded tissues to identify the underlying molecular mechanisms contributing to the disproportionate of PCa among AA men.

Methods: Microarray data of 619 PCa patients, 412 AA and 207 CA, were retrieved from 11 data sets deposited in Gene Expression Omnibus (GEO) database. False discovery rates (FDR) were used for reporting differentially expressed genes and the differentially regulated pathways of these genes were predicted. To validate the microarray data, qPCR analyses were performed in forty paraffin-embedded samples collected from AA and CA men.

Results: Of 362 differential transcripts of array data, TIMP4, LTC4S, SHH, ADIPOQ, and ALOX12 were downregulated (p&lt;0.001) while KLK2, COX5A, AZGP1, AMD1, and ALDH1A3 were upregulated (p&lt;0.001) in PCa AA compared to CA men. qPCR analyses demonstrated that OAT, NKX3, LTC4S, APPL2, TPD52, ALDH, and AMD1 were significantly upregulated (p&lt;0.05) in AA regarding CA men with PCa. Overexpression of OAT, LTC4S, and TPD52 in AA cell lines was confirmed by Western blot analysis. These genes were involved in regulation of cell apoptosis, lipid metabolism, migration, angiogenesis, and response to reactive oxygen species. These transcripts are involved in focal adhesion, PI3K/Akt, EGFR, beta-catenin, and MAPK signaling pathways.

Conclusions: Gene expression data from PCa specimens and microarray suggest that dysregulation of transcripts in PCa of AA compared to CA men may underlie health disparity of PCa. These data might provide new insights into development of reliable diagnostic and prognostic markers of aggressive PCa.

Citation Format: Hamdy Ali, Pei-Yau Lung, Shaimaa Gad, Andrew Sholl, Hamed I. Ali, Jinfeng Zhang, Zakaria Y. Abd Elmageed. Transcriptome-wide profiling identifies novel differential genes associated with health disparity of prostate cancer [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr B41.

Structural-based design, synthesis, and antitumor activity of novel alloxazine analogues with potential selective kinase inhibition

Protein kinases are promising therapeutic targets for cancer therapy. Here, we applied multiple approaches to optimize the potency and selectivity of our reported alloxazine scaffold. Flexible moieties at position 2 of the hetero-tricyclic system were incorporated to fit into the ATP binding site and extend to the adjacent allosteric site and selectively inhibit protein kinases. This design led to potential selective inhibition of ABL1, CDK1/Cyclin A1, FAK, and SRC kinase by 30-59%. Cytotoxicity was improved by ∼50 times for the optimized lead (10b; IC₅₀ = 40 nM) against breast cancer (MCF-7) cells. Many compounds revealed potential cytotoxicity against ovarian (A2780) and colon carcinoma (HCT116) cells of ∼10-30 time improvement (IC₅₀ 5-17 nM). The results of the Annexin-V/PI apoptotic assay demonstrated that many compounds induced significantly early (89-146%) and a dramatically late (556-1180%) cell death in comparison to the vehicle control of MCF-7 cells. SAR indicated that 5-deazaalloxazines have a higher selectivity for Abl-1 and FAK kinases than alloxazines. The correlations between GoldScore fitness into FAK and SRC kinases and IC₅₀ against MCF-7 and A2780 cells were considerable (R²: 0.86-0.98).

Part II: New candidates of pyrazole-benzimidazole conjugates as checkpoint kinase 2 (Chk2) inhibitors

The development of checkpoint kinase 2 (Chk2) inhibitors for the treatment of cancer has been an ongoing and attractive objective in drug discovery. In this study, twenty-one feasible pyrazole-benzimidazole conjugates were synthesized to study their effect against Chk2 activity using Checkpoint Kinase Assay. The antitumor activity of these compounds was investigated using SRB assay. A potentiation effect of the synthesized Chk2 inhibitors was also investigated using the genotoxic anticancer drugs cisplatin and doxorubicin on breast carcinoma, (ER+) cell line (MCF-7). In vivo Chk2 and antitumor activities of 8d as a single-agent, and in combination with doxorubicin, were evaluated in breast cancer bearing animals induced by N-methylnitrosourea. The effect of 8d alone and in combination with doxorubicin was also studied on cell-cycle phases of MCF-7 cells using flow cytometry analysis. The results revealed their potencies as Chk2 inhibitors with IC₅₀ ranges from 9.95 to 65.07 nM. Generally the effect of cisplatin or doxorubicin was potentiated by the effect of most of the compounds that were studied. The in vivo results indicated that the combination of 8d and doxorubicin inhibited checkpoint kinase activity more than either doxorubicin or 8d alone. There was a positive correlation between checkpoint kinase inhibition and the improvement observed in histopathological features. Single dose treatment with doxorubicin or 8d produced S phase cell cycle arrest whereas their combination created cell cycle arrest at G2/M from 8% in case of doxorubicin to 51% in combination. Gold molecular modelling studies displayed a high correlation to the biological results.

LY2087101 and dFBr share transmembrane binding sites in the (α4)3(β2)2 Nicotinic Acetylcholine Receptor

Positive allosteric modulators (PAMs) of nicotinic acetylcholine receptors (nAChRs) have potential therapeutic application in neuropathologies associated with decrease in function or loss of nAChRs. In this study, we characterize the pharmacological interactions of the nAChRs PAM, LY2087101, with the α4β2 nAChR using mutational and computational analyses. LY2087101 potentiated ACh-induced currents of low-sensitivity (α4)3(β2)2 and high-sensitivity (α4)2(β2)3 nAChRs with similar potencies albeit to a different maximum potentiation (potentiation I _max  = ~840 and 450%, respectively). Amino acid substitutions within the α4 subunit transmembrane domain [e.g. α4Leu256 and α4Leu260 within the transmembrane helix 1 (TM1); α4Phe316 within the TM3; and α4Gly613 within TM4] significantly reduced LY2087101 potentiation of (α4)3(β2)2 nAChR. The locations of these amino acid residues and LY2087101 computational docking analyses identify two LY2087101 binding sites: an intrasubunit binding site within the transmembrane helix bundle of α4 subunit at the level of α4Leu260/α4Phe316 and intersubunit binding site at the α4:α4 subunit interface at the level of α4Leu256/α4Ile315 with both sites extending toward the extracellular end of the transmembrane domain. We also show that desformylflustrabromine (dFBr) binds to these two sites identified for LY2087101. These results provide structural information that are pertinent to structure-based design of nAChR allosteric modulators.

Synthesis and molecular docking study of new benzofuran and furo[3,2-g]chromone-based cytotoxic agents against breast cancer and p38α MAP kinase inhibitors

This study deals with synthesis of a new set of benzofuran and 5H-furo[3,2-g]chromone linked various heterocyclic functionalities using concise synthetic approaches aiming to gain new antiproliferative candidates against MCF-7 breast cancer cells of p38α MAP kinase inhibiting activity. The biological data proved the significant sensitivity of breast cancer cell lines MCF-7 towards most of the prepared compounds in comparison with doxorubicin. In addition, compounds IIa,b, Va,b, VIa,b, VIIa,b, VIIIa,b, XIc showed significant in vitro p38α MAPK inhibiting potency comparable to the reference standard SB203580. Cell cycle analysis and apoptosis detection data demonstrated that compound VIa induced G2/M phase arrest and apoptosis in MCF-7 cancer cells, in addition to its activation of the caspases-9 and -3. Gold molecular docking studies rationalized the highly acceptable correlation between the calculated docking scores of fitness and the biological data of p38α MAP kinase inhibition. The newly prepared benzofuran and 5H-furo[3,2-g]chromone derivatives might be considered as new promising nuclei in anti-breast cancer chemotherapeutics for further functionalization, optimization and in-depth biological studies.

Discovery of new indomethacin-based analogs with potentially selective cyclooxygenase-2 inhibition and observed diminishing to PGE2 activities

New ring-extended analogs of indomethacin were designed based on the structure of active binding site of both COX-1 and COX-2 isoenzymes and the interaction pattern required for selective inhibition of COX-2 to improve its selectivity against COX-2. The strategy adopted for designing the new inhibitors involved i) ring extension of indomethacin to reduce the possibility of analogs to be accommodated into the narrow hydrophobic tunnel of COX-1, ii) deletion of carboxylic acid to reduce the possibility of inhibitor to form salt bridge with Arg120 and eventually prevent COX-1 inhibition, and iii) introduction of methylsulfonyl group to increase the opportunity of the analogs to interact with the polar side pocket that's is crucial for inhibition process of COX-2. The three series of tetrahydrocarbazoles involving 4, 5, 9, 10 and 12 were synthesized in quantitative yields adopting limited number of reaction steps, and applying laboratory friendly reaction conditions. In vitro and in vivo assays for data profiling the new candidates revealed the significant improvement in the potency and selectivity against COX-2 of 6-methoxytetrahydrocarbazole 4 (IC₅₀ = 0.97 μmol) to verify the effect of ring extension in comparison to indomethacin (IC₅₀ = 2.63 μmol), and 6-methylsulfonyltetrahydrocarbazole 10a (IC₅₀ = 0.28 μmol) to verify the effect of ring extension and introduction of methylsulfonyl group. 9-(4-chlorobenzoyl)-6-(methylsulfonyl)-1,2,3,9-tetrahydro-4H-carbazol-4-one 12a showed the most potential and selective activity against COX-2 (IC₅₀ = 0.23 μmol) to be with superior potency to Celecoxib (IC₅₀ = 0.30 μmol). Consistently, 12a was the most active with all the other anti-inflammatory test descriptors and its activity in diminishing the PGE2 with the other analogs confirmed the elaboration of new class of selective COX-2 inhibitors beyond the diarylsulfonamides as a previously common class of selective COX-2 inhibitors. Molecular docking study revealed the high binding score of compound 12a (-30.78 kcal/mol), with less clash contribution (7.2) that is close to indomethacin. Also, 12a showed low conformation entropy score (1.40). Molecular dynamic (MD) simulation identified the equilibrium of both potential and kinetic energies.

Pyrrolizines: Design, synthesis, anticancer evaluation and investigation of the potential mechanism of action

A novel set of pyrrolizine-5-carboxamides has been synthesized and evaluated for their anticancer potential against human breast MCF-7, lung carcinoma A549 and hepatoma Hep3B cancer cell lines. Compound 10c was the most active against MCF-7 with IC₅₀ value of 4.72µM, while compound 12b was the most active against A549 and Hep3B cell lines. Moreover, kinases/COXs inhibition and apoptosis induction were suggested as potential molecular mechanisms for the anticancer activity of the novel pyrrolizines based on their structural features. The new compounds significantly inhibited COX-1 and COX-2 with IC₅₀ values in the ranges of 5.78-11.96µM and 0.1-0.78µM, respectively with high COX-2 selectivity over COX-1. Interestingly, the most potent compound in MTT assay, compound 12b, exhibited high inhibitory activity against COX-2 with selectivity index (COX-1/COX-2)>100. Meanwhile, compound 12b displayed weak to moderate inhibition of six kinases with inhibition% (7-20%) compared to imatinib (inhibition%=1-38%). The results of cell cycle analysis, annexin V PI/FITC apoptosis assay and caspase-3/7 assay revealed that compound 12b has the ability to induce apoptosis. The docking results of compound 12b into the active sites of COXs, ALK1 and Aurora kinases indicated that it fits nicely inside their active sites. Overall, the current study highlighted the significant anticancer activity of the newly synthesized pyrrolizines with a potential multi-targeted mechanism which could serve as a base for future studies and further structural optimization into potential anticancer agents.

Part I: Design, synthesis and biological evaluation of novel pyrazole-benzimidazole conjugates as checkpoint kinase 2 (Chk2) inhibitors with studying their activities alone and in combination with genotoxic drugs

Activated checkpoint kinase 2 (Chk2) is a tumor suppressor as one of the main enzymes that affect the cell cycle. 2-Biarylbenzimidazoles are potent selective class of Chk2 inhibitors; the structure-based design was applied to synthesize a new series of this class with replacing the lateral aryl group by substituted pyrazoles. Ten pyrazole-benzimidazole conjugates from the best fifty candidates according to docking programs have been subjected to chemical synthesis in this study. The activities of the conjugates 5-14 as checkpoint kinase inhibitors and as antitumor alone and in combination with genotoxic drugs were evaluated. The effect of compounds 7 and 12 on cell-cycle phases was analyzed by flow cytometry analysis. Antitumor activity of compounds 7 and 12 as single-agents and in combinations with doxorubicin was assessed in breast cancer bearing animals induced by MNU. The Results indicated that compounds 5-14 inhibited Chk2 activity with high potency (IC₅₀ 52.8 nM-5.5 nM). The cytotoxicity of both cisplatin and doxorubicin were significantly potentiated by the most of the conjugates against MCF-7 cell lines. Compounds 7 and 12 and their combinations with doxorubicin induced the cell cycle arrest in MCF-7 cells. Moreover, compound 7 exhibited marked higher antitumor activity as a single agent in animals than it's combination with doxorubicin or doxorubicin alone. The combination of compound 12 with doxorubicin was greatly effective on animal than their single-dose treatment. In conclusion, pyrazole-benzimidazole conjugates are highly active Chk2 inhibitors that have anticancer activity and potentiate activity of genotoxic anticancer therapies and deserve further evaluations.

Synthesis and molecular docking studies of new furochromone derivatives as p38α MAPK inhibitors targeting human breast cancer MCF-7 cells

Based on the reported high expression of p38α MAP kinase in invasive breast cancers and the activity of different functionalized chromone derivatives as p38α inhibitors, a new set of 4,9-dimethoxy/4-methoxy-7-methyl-5-oxo-5H-furo[3,2-g]chromone derivatives were efficiently synthesized aiming to introduce new p38α MAP kinase suppressors as new anti-breast cancer tools. Using GOLD program, molecular docking study of the target compounds into p38α MAP kinase binding pocket was performed to highlight their scores, mode of binding and the important interactions to the amino acid residues of the enzyme. MTT assay investigated that fifteen target compounds produced marked cytotoxic potency higher than that obtained by Doxorubicin against MCF-7 cancer cells of IC₅₀ values ranging from 0.007 to 0.17μM vs IC₅₀; 0.62μM of doxorubicin. Eleven selected compounds were evaluated for their inhibitory potency against p38α MAPK kinase. The derivatives IVa, Va,b, VIa, IXb and XIIIa represented significant activity (IC₅₀; 0.19-0.67μM) comparing to the reference drug SB203580 (IC₅₀; 0.50μM). In virtue of its promising cytotoxic and p38α MAP kinase inhibition potency, the furochromone derivative IXb was selected as a representative example to investigate its mechanistic effects on cell cycle progression and induction of apoptosis in MCF-7 cell lines. The results showed that the compound IXb induced cell cycle cessation at G2/M phase preventing its mitotic cycle, alongside its noteworthy activation of caspases-9 and -3 which might mediate the apoptosis of MCF-7 cells.

Synthesis and biological evaluation of indole-2-carboxamides bearing photoactivatable functionalities as novel allosteric modulators for the cannabinoid CB1 receptor

5-Chloro-3-ethyl-N-(4-(piperidin-1-yl)phenethyl)-1H-indole-2-carboxamide (ORG27569, 1) is a prototypical allosteric modulator for the cannabinoid CB1 receptor. Based on this indole-2-carboxamide scaffold, we designed and synthesized novel CB1 allosteric modulators that possess photoactivatable functionalities, which include benzophenone, phenyl azide, aliphatic azide and phenyltrifluoromethyldiazrine. To assess their allosteric effects, the dissociation constant (KB) and allosteric binding cooperativity factor (α) were determined and compared to their parent compounds. Within this series, benzophenone-containing compounds 26 and 27, phenylazide-containing compound 28, and the aliphatic azide containing compound 36b showed allosteric binding parameters (KB and α) comparable to their parent compound 1, 7, 8, and 9, respectively. We further assessed these modulators for their impact on G-protein coupling activity. Interestingly, these compounds exhibited negative allosteric modulator properties in a manner similar to their parent compounds, which antagonize agonist-induced G-protein coupling. These novel CB1 allosteric modulators, possessing photoactivatable functionalities, provide valuable tools for future photo-affinity labeling and mapping the CB1 allosteric binding site(s).

Abstract LB-098: Antitumor studies: Design, synthesis, antitumor activity and molecular docking study of novel 2-deoxo-2-substituted-5-deazaalloxazines

Cancer is the major threat to the public health worldwide, thereby we have a considerable interest to get potential antitumor agents via computational design, synthesis, functional elucidation, and biological evaluation of different deazaalloxazine analogs. Many of these compounds revealed higher selectivities against different tumor cell lines.

In the study the structure activity relationships (SAR) of the proposed derivatives was investigated, by applying structure based drug design (SBDD) using most advanced molecular modeling tool programs, namely: AutoDock 4.2 and Accelrys Discovery studio 2.0. These computational approaches aim to increase the speed and efficiency in the drug discovery process. The reasonable drug candidates were subjected to the chemical synthesis and biological in vitro test against different tumor cell lines. The docking study of the synthesized and the rationally designed derivatives was carried out using PTKs as target enzymes which was early reported as a proposed pathway for inhibition of cancer. The main outcome of this study is the synthesis of novel 2-methylthio, 2-(substituted alkyl amino), 2-(heterocyclic substituted), 2-amino, 2,4-dioxo and 2-deoxo-5-deazaalloxazine derivatives. Their antitumor activities against human T-cell acute lymphoblastoid leukemia cell line (CCRF-HSB-2), human oral epidermoid carcinoma cell line (KB), human breast cancer cell line (MCF-7) and human cervical cancer cell line (Hela) have been investigated in vitro. Many compounds showed promising antitumor activities. Furthermore, AutoDock study has been done by binding of the 5-deazaalloxazine analogs into c-kit PTK (PDB code: 1t46), where a good correlation between their IC50 and AutoDock binding free energy was exhibited.

Citation Format: Sawsan A. Mahmoud, Mosaad S. Mohamed, Nageh A. Abou Taleb, Tomohisa Nagamatsu, Hamed I. Ali. Antitumor studies: Design, synthesis, antitumor activity and molecular docking study of novel 2-deoxo-2-substituted-5-deazaalloxazines. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-098. doi:10.1158/1538-7445.AM2015-LB-098

Design, synthesis and anticancer activity of furochromone and benzofuran derivatives targeting VEGFR-2 tyrosine kinase

Furochromone and benzofuran derivatives were synthesized, docked and evaluated for their anti-VEGFR-2 activity, cytotoxicity, and in vivo antiprostate cancer activity.

Synthesis, docking and biological activities of novel hybrids celecoxib and anthraquinone analogs as potent cytotoxic agents

Herein, novel hybrid compounds of celecoxib and 2-aminoanthraquinone derivatives have been synthesized using condensation reactions of celecoxib with 2-aminoanthraquinone derivatives or 2-aminoanthraquinon with celecoxib derivatives. Celecoxib was reacted with different acid chlorides, 2-chloroethylisocyanate and bis (2-chloroethyl) amine hydrochloride. These intermediates were then reacted with 2-aminoanthraquinone. Also the same different acid chlorides and 2-chloroethylisocyanate were reacted with 2-aminoanthraquinone and the resulting intermediates were reacted with celecoxib to give isomers for the previous compounds. The antitumor activities against hepatic carcinoma tumor cell line (HEPG2) have been investigated in vitro, and all these compounds showed promising activities, especially compound 3c, 7, and 12. Flexible docking studies involving AutoDock 4.2 was investigated to identify the potential binding affinities and the mode of interaction of the hybrid compounds into two protein tyrosine kinases namely, SRC (Pp60v-src) and platelet-derived growth factor receptor, PDGFR (c-Kit). The compounds in this study have a preferential affinity for the c-Kit PDGFR PTK over the non-receptor tyrosine kinase SRC (Pp60v-src).

Optimization of chemical functionalities of indole-2-carboxamides to improve allosteric parameters for the cannabinoid receptor 1 (CB1)

5-Chloro-3-ethyl-N-(4-(piperidin-1-yl)phenethyl)-1H-indole-2-carboxamide (1; ORG27569) is a prototypical allosteric modulator for the cannabinoid type 1 receptor (CB1). Here, we reveal key structural requirements of indole-2-carboxamides for allosteric modulation of CB1: a critical chain length at the C3-position, an electron withdrawing group at the C5-position, the length of the linker between the amide bond and the phenyl ring B, and the amino substituent on the phenyl ring B. These significantly impact the binding affinity (K_B) and the binding cooperativity (α). A potent CB1 allosteric modulator 5-chloro-N-(4-(dimethylamino)phenethyl)-3-propyl-1H-indole-2-carboxamide (12d) was identified. It exhibited a K_B of 259.3 nM with a strikingly high binding α of 24.5. We also identified 5-chloro-N-(4-(dimethylamino)phenethyl)-3-hexyl-1H-indole-2-carboxamide (12f) with a K_B of 89.1 nM, which is among the lowest K_B values obtained for any allosteric modulator of CB1. These positive allosteric modulators of orthosteric agonist binding nonetheless antagonized the agonist-induced G-protein coupling to the CB1 receptor, yet induced β-arrestin mediated ERK1/2 phosphorylation.

Structure-activity relationship study of indole-2-carboxamides identifies a potent allosteric modulator for the cannabinoid receptor 1 (CB1)

The cannabinoid CB1 receptor is involved in complex physiological functions. The discovery of CB1 allosteric modulators generates new opportunities for drug discovery targeting the pharmacologically important CB1 receptor. 5-Chloro-3-ethyl-N-(4-(piperidin-1-yl)phenethyl)-1H-indole-2-carboxamide (ORG27569; 1) represents a new class of indole-2-carboxamides that exhibit allostery of CB1. To better understand the SAR, a group of indole-2-carboxamide analogues were synthesized and assessed for allostery of the CB1 receptor. We found that within the structure of indole-2-carboxamides, the presence of the indole ring is preferred for maintaining the modulator's high binding affinity for the allosteric site but not for generating allostery on the orthosteric site. However, the C3 substituents of the indole-2-carboxamides significantly impact the allostery of the ligand. A robust CB1 allosteric modulator 5-chloro-N-(4-(dimethylamino)phenethyl)-3-pentyl-1H-indole-2-carboxamide (11j) was identified. It showed an equilibrium dissociation constant (KB) of 167.3 nM with a markedly high binding cooperativity factor (α = 16.55) and potent antagonism of agonist-induced GTPγS binding.

Molecular Docking and Prediction of Pharmacokinetic Properties of Dual Mechanism Drugs that Block MAO-B and Adenosine A(2A) Receptors for the Treatment of Parkinson's Disease

Monoamine oxidase B (MAO-B) inhibitory potential of adenosine A(2A) receptor (AA(2A)R) antagonists has raised the possibility of designing dual-target-directed drugs that may provide enhanced symptomatic relief and that may also slow the progression of Parkinson's disease (PD) by protecting against further neurodegeneration. To explain the dual inhibition of MAO-B and AA(2A)R at the molecular level, molecular docking technique was employed. Lamarckian genetic algorithm methodology was used for flexible ligand docking studies. A good correlation (R(2)= 0.524 and 0.627 for MAO-B and AA(2A)R, respectively) was established between docking predicted and experimental K(i) values, which confirms that the molecular docking approach is reliable to study the mechanism of dual interaction of caffeinyl analogs with MAO-B and AA(2A)R. Parameters for Lipinski's "Rule-of-Five" were also calculated to estimate the pharmacokinetic properties of dual-target-directed drugs where both MAO-B inhibition and AA(2A)R antagonism exhibited a positive correlation with calculated LogP having a correlation coefficient R(2) of 0.535 and 0.607, respectively. These results provide some beneficial clues in structural modification for designing new inhibitors as dual-target-directed drugs with desired pharmacokinetic properties for the treatment of PD.

Design, synthesis, biological evaluation, and comparative Cox1 and Cox2 docking of p-substituted benzylidenamino phenyl esters of ibuprofenic and mefenamic acids

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently associated with gastric mucosal and renal adverse reactions, related to inhibition of cyclooxygenase1 (Cox1) in tissues where prostaglandins exert physiological effects. This led us to develop a set of ibuprofenic acid and mefenamic acid esters, namely: 4-((4-substituted benzylidene)amino)phenyl 2-(4-isobutylphenyl)propanoate and 4-((4-substituted benzylidene)amino)phenyl 2-((2,4-dimethylphenyl)amino)benzoate analogs, which were synthesized by condensation of the corresponding acids with Schiff's bases [4-(4-substituted benzylideneamino)phenols] involving dicyclohexyl carbodiimmide (DCC) as mild dehydrating agent. The main objective is to reduce the GIT toxicity associated with acute and chronic NSAIDs use. Anti-inflammatory, analgesic as well as ulcerogenic activities of the prepared esters were evaluated in vivo and compared with that of ibuprofen as reference standard in all screenings, involving the carrageenan induced paw oedema model and hot plate method. Most of the synthesized esters showed remarkable analgesic and anti-inflammatory activities. Interestingly, all of the compounds were found to be non-ulcerogenic under the tested conditions. This evidence have suggested that modification of the carboxyl function of representative NSAIDs results in retained or enhanced anti-inflammatory and analgesic activities with reduced ulcerogenic potential. Additionally, a comparative AutoDock study into Cox 1 and Cox2 has been done involving both of rigid and flexible docking for potential selectivity of our compounds within different Cox enzymes and to find out the binding orientation of these novel esters into their binding site. Some of the newly prepared aforementioned compounds showed considerable more Cox2 over Cox1 binding affinities by flexible docking better than rigid one.

The prevalence and trends of overweight, obesity and nutrition-related non-communicable diseases in the Arabian Gulf States

This paper reviews studies on the prevalence of overweight, obesity and related nutrition-related non-communicable diseases in Bahrain, Kuwait, Qatar, Oman, Saudi Arabia and the UAE. Obesity is common among women; while men have an equal or higher overweight prevalence. Among adults, overweight plus obesity rates are especially high in Kuwait, Qatar and Saudi Arabia, and especially among 30-60 year olds (70-85% among men; 75-88% among women), with lower levels among younger and elderly adults. The rate of increase in obesity was pronounced in Saudi Arabia and Kuwait. Prevalence of obesity is high among Kuwaiti and Saudi pre-schoolers (8-9%), while adolescent overweight and obesity are among the highest in the world, with Kuwait having the worst estimates (40-46%); however, comparison of child data is difficult because of differing standards. Among nutrition-related non-communicable diseases, hypertension and diabetes levels are very high and increase with age, with the UAE performing the worst because of a rapid rate of increase between 1995 and 2000. Additional monitoring of the prevalence of metabolic syndrome and cancers is necessary. Nationally representative longitudinal surveys with individual, household and community-level information are needed to determine the importance of various factors that contribute to these troubling trends.

Antitumor studies -- part 2: structure-activity relationship study for flavin analogs including investigations on their in vitro antitumor assay and docking simulation into protein tyrosine kinase

Various analogs of flavins, 5-deazaflavins, and flavin-5-oxides were docked into the binding site of protein tyrosine kinase pp60(c-src), and some of them were assayed for their potential antitumor and PKC (protein kinase C) inhibitory activities in vitro. The results considering SAR (structure-activity relationship) revealed that the higher binding affinities obtained include compounds with the structure modifications on the flavin or 5-deazaflavin skeleton, namely, NH(2) or Ph (phenyl-) group at the C-2 position and so on. Computationally designed compounds 4a, 6a, b, 7, 11b, c, 12, 15, and 22c exhibited good docking results suggesting that they are potentially active antitumor agents. These compounds have 1-3 phenyl moieties, which are thought to be responsible for the planar aromatic fitting or electrostatic attraction onto the groove of the binding pocket.

Antitumor studies. Part 3: Design, synthesis, antitumor activity, and molecular docking study of novel 2-methylthio-, 2-amino-, and 2-(N-substituted amino)-10-alkyl-2-deoxo-5-deazaflavins

Various novel 10-alkyl-2-deoxo-2-methylthio-5-deazaflavins have been synthesized by reaction of 6-(N-alkylanilino)-2-methylthiopyrimidin-4(3H)-ones with Vilsmeier reagent. The similar 2-(N-substituted amino) derivatives were prepared by nucleophilic replacement reaction of the 2-methylthio moiety by appropriate amines. The 2-oxo derivatives (i.e., 5-deazaflavins) were obtained by acidic hydrolysis of the 2-methylthio derivatives. The antitumor activities against CCRF-HSB-2 and KB cells and the antiviral activities against HSV-1 and HSV-2 have been investigated in vitro, and many compounds showed promising antitumor activities. Furthermore, AutoDock molecular docking into PTK has been done for lead optimization of these compounds as potential PTK inhibitors. Whereas, the designed 2-deoxo-5-deazaflavins connected with amino acids at the 2-position exhibited the good binding affinities into PTK with more hydrogen bonds.

A Study on Medicinal Plants from Malaysia Focused onAcalypha siamensisOliv.exGage. Isolation and Structure of a New Tetraterpene, Acalyphaser A

As a part of our chemical studies on Malaysian medicinal plants, five Malaysian plant species were evaluated by cytotoxicity assays using P388 murine leukemia cells. Since Acalypha siamensis exhibited the strongest growth inhibition, its constituents were studied as the object of search for bioactive materials. A novel tetraterpene, acalyphaser A (1), was isolated in the course of the purification. Its structure was elucidated on the basis of 1D- and 2D-NMR techniques, and mass spectrometry.

Antitumor studies. Part 1: design, synthesis, antitumor activity, and AutoDock study of 2-deoxo-2-phenyl-5-deazaflavins and 2-deoxo-2-phenylflavin-5-oxides as a new class of antitumor agents

Novel 2-deoxo-2-phenyl-5-deazaflavins and 2-deoxo-2-phenylflavin-5-oxides were prepared as a new class of antitumor agents and showed significant antitumor activities against NCI-H 460, HCT 116, A 431, CCRF-HSB-2, andKB cell lines. In vivo investigation, 2-deoxo-10-methyl-2-phenyl-5-deazaflavin exhibited the effective antitumor activity against A 431 human adenocarcinoma cells transplanted subcutaneously into nude mouse. Furthermore, AutoDock study has been done by binding of the flavin analogs into PTK pp60(c-src), where a good correlation between their IC(50) and AutoDock binding free energy was exhibited. In particular, 2-deoxo-2-phenylflavin-5-oxides exhibited the highest potential binding affinity within the binding pocket of PTK.

Enzyme-catalyzed removal of phenol from refinery wastewater: feasibility studies

Phenols are present in petroleum refining wastewater. An enzymatic method for removing phenols from industrial aqueous effluent has been developed in the past several years. In this method, a peroxidase enzyme catalyzes the oxidation of phenol by hydrogen peroxide generation of phenoxyl radicals. These radicals diffuse from the active center of the enzyme into solution and react nonenzymatically to eventually form higher oligomers and polymers, which can be removed from wastewater by conventional coagulation and sedimentation or filtration. In this study, Arthromyces ramosus peroxidase (ARP) was applied to treat a petroleum refining wastewater containing 2 mM (188 mg/L) phenol in a batch and continuous-flow system. The latter consisted of a plug-flow reactor (PFR) where the reaction took place between phenol and hydrogen peroxide catalyzed by the enzyme in the presence of polyethylene glycol (PEG). A flocculation tank followed the PFR where alum and sodium hydroxide were added and then the polymers formed were settled in a sedimentation tank and removed from the system. Most (95 to 99%) of the phenol was removed by the same dose of ARP required for the treatment of synthetic wastewater containing an equal amount of phenol. Polyethylene glycol, as an additive, reduced enzyme inactivation and consequently reduced the enzyme dose and the cost of the treatment process. Step feeding of hydrogen peroxide was not effective in reducing the enzyme requirement. A significant removal of chemical oxygen demand was achieved when using PEG to reduce the enzyme dose.