Design, synthesis, and apoptotic antiproliferative action of new 1,2,3-triazole/1,2,4-oxadiazole hybrids as dual EGFR/VEGFR-2 inhibitors.

A novel series of 1,2,3-triazole/1,2,4-oxadiazole hybrids (7a-o) was developed as dual inhibitors of EGFR/VEGFR-2. Compounds 7a-o were evaluated as antiproliferative agents with Erlotinib as the reference drug. Results demonstrated that most of the tested compounds showed significant antiproliferative action with GI50 values ranging from 28 to 104 nM, compared to Erlotinib (GI50 = 33 nM), and compounds 7i-m were the most potent. Compounds 7h, 7i, 7j, 7k, and 7l were evaluated as dual EGFR/VEGFR-2 inhibitors. These in vitro experiments demonstrated that compounds 7j, 7k, and 7l are potent antiproliferative agents that may operate as dual EGFR/VEGFR-2 inhibitors. Compounds 7j, 7k, and 7l were evaluated for their apoptotic potential activity, where findings indicated that compounds 7j, 7k, and 7l promote apoptosis by activating caspase-3, 8, and Bax and down-regulating the anti-apoptotic Bcl-2. Molecular docking simulations show the binding mode of the most active antiproliferative compounds within EGFR and VEGFR-2 active sites.

New 1,2,3-Triazole/1,2,4-triazole Hybrids as Aromatase Inhibitors: Design, Synthesis, and Apoptotic Antiproliferative Activity.

A novel series of 1,2,3-triazole/1,2,4-triazole hybrids 5a, 5b, and 6a-i was designed and synthesized as antiproliferative agents targeting aromatase enzymes. The antiproliferative activity of the new hybrids against four cancer cells was studied using Erlotinib as a control. Compounds 6a and 6b demonstrated the highest antiproliferative activity among these hybrids, with GI50 values of 40 nM and 35 nM, respectively. Compound 6b was the most potent derivative, with a GI50 of 35 nM, comparable to Erlotinib's GI50 of 33 nM. Compound 6b inhibited all cancer cell lines with comparable efficacy to Erlotinib. Compounds 5a, 5b, and 6a-i were tested for inhibitory action against aromatase as a potential target for their antiproliferative activity. Results revealed that compounds 6a and 6b were the most potent aromatase inhibitors, with IC50 values of 0.12 ± 0.01 µM and 0.09 ± 0.01 µM, respectively, being more potent than the reference Ketoconazole (IC50 = 2.6 ± 0.20 µM) but less potent than Letrozole (IC50 = 0.002 ± 0.0002). These findings indicated that compounds 6a and 6b had significant aromatase inhibitory action and are potential antiproliferative candidates. The findings were further linked to molecular docking investigations, which gave models of strong interactions with the aromatase domain for inhibitors with high binding scores.

Design, synthesis, and modelling study of new 1,2,3-triazole/chalcone hybrids with antiproliferative action as epidermal growth factor receptor inhibitors.

A novel series of 1,2,3-triazole/chalcone hybrids 6a-n was designed and synthesized using a molecular hybridization approach to develop a new cytotoxic agent capable of targeting epidermal growth factor receptor (EGFR) and/or BRAF. The antiproliferative effect of the novel hybrids was investigated against four cancer cells using doxorubicin as a reference. Hybrids 6a, 6d, 6f-h, and 6n have the highest antiproliferative activity (IC50 values 0.95-1.80 µM) compared to doxorubicin (IC50 1.14 µM). The most potent antiproliferative derivative, compound 6d, was also the most potent EGFR inhibitor with an IC50 of 0.09 ± 0.05 µM, which is comparable to the reference Erlotinib (IC50  = 0.05 ± 0.03 µM). 6d has modest BRAF inhibitory action with an IC50 of 0.90 ± 0.10 µM. The findings were also related to molecular docking studies, which provided models of strong interactions with the EGFR-TK domain for the inhibitors. In cell cycle analysis, hybrid 6d caused a cell cycle arrest at the G1 transition phase.

New pyrimidine/thiazole hybrids endowed with analgesic, anti-inflammatory, and lower cardiotoxic activities: Design, synthesis, and COX-2/sEH dual inhibition.

Some cyclooxygenase (COX)-2 selective medications were withdrawn from the market just a few years after their production due to cardiovascular side effects. In this study, a new series of pyrimidine/thiazole hybrids 7a-p was synthesized as selective COX-2/soluble epoxide hydrolase (sEH) inhibitors with analgesic and anti-inflammatory effects, and lower cardiotoxicity effects. The target compounds were synthesized and in vitro tested against COX-1, COX-2, and sEH enzymes. Hybrids 7j, 7k, and 7i showed the greatest COX-2-inhibitory activity and were discovered to be the most potent dual COX-2/sEH inhibitors. In vivo tests revealed that these hybrids were the most active analgesic/anti-inflammatory agents, with improved ulcerogenic and cardioprotective properties. Finally, the most active dual inhibitors were docked into COX-2/sEH active regions to explain their binding mechanisms.

New 1,3,4-oxadiazoles linked with the 1,2,3-triazole moiety as antiproliferative agents targeting the EGFR tyrosine kinase.

A series of 1,3,4-oxadiazole-1,2,3-triazole hybrids bearing different pharmacophoric moieties has been designed and synthesized. Their antiproliferative activity was evaluated against four human cancer cell lines (Panc-1, MCF-7, HT-29, and A-549) using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The preliminary activity test displayed that the most active compounds, 6d, 6e, and 8a-e, suppressed cancer cell growth (GI50 = 0.23-2.00 µM) comparably to erlotinib (GI50 = 0.06 µM). Compounds 6d, 6e, and 8a-e inhibited the epidermal growth factor receptor tyrosine kinase (EGFR-TK) at IC50 = 0.11-0.73 µM, compared to erlotinib (IC50 = 0.08 ± 0.04 µM). The apoptotic mechanism revealed that the most active hybrid 8d induced expression levels of caspase-3, caspase-9, and cytochrome-c in the human cancer cell line Panc-1 by 7.80-, 19.30-, and 13-fold higher than doxorubicin. Also, 8d increased the Bax level by 40-fold than doxorubicin, along with decreasing Bcl-2 levels by 6.3-fold. Cell cycle analysis after treatment of Panc-1 cells with hybrid 8d revealed a high proportion of cell accumulation (41.53%) in the pre-G1 phase, indicating cell cycle arrest at the G1 transition. Computational docking of the 8d and 8e hybrids with the EGFR binding site revealed their ability to bind with EGFR similar to erlotinib. Finally, in silico absorption, distribution, metabolism, and excretion/pharmacokinetic studies for the most active hybrids are discussed.

Novel 1,2,4-triazole derivatives as apoptotic inducers targeting p53: Synthesis and antiproliferative activity.

A series of novel thiazolo[3,2-b][1,2,4]-triazoles 3a-n has been synthesized and evaluated in vitro as potential antiproliferative. Compounds 3b-d exhibited significant antiproliferative activity. Compound 3b was the most potent with Mean GI50 1.37 µM comparing to doxorubicin (GI50 1.13 µM). The transcription effects of 3b, 3c and 3d on the p53 were assessed and compared with the reference doxorubicin. The results revealed an increase of 15-27 in p53 level compared to the test cells and that p53 protein level of 3b, 3c and 3d was significantly inductive (1419, 571 and 787 pg/mL, respectively) in relation to doxorubicin (1263 pg/mL). The docking study of the new compounds 3a-n revealed high binding scores for the new compounds toward p53 binding domain in MDM2. The docking analyses revealed the highest affinities for compounds 3b-d which induced p53 activity in MCF-7 cancer cells. Compound 3b which exhibited the highest antiproliferative activity and induced the highest increase in p53 level in MCF-7 cells showed also the highest affinity to MDM2.

Design and synthesis of novel 2,3-dihydropyrazino[1,2-a]indole-1,4-dione derivatives as antiproliferative EGFR and BRAFV600E dual inhibitors.

Recent studies have shown additive and synergistic effects associated with the combination of kinase inhibitors. BRAFV600E and EGFR are attractive targets for many diseases treatments and have been studied extensively. In keeping with our interest in developing anticancer targeting EGFR and BRAFV600E, a novel series of 2,3-dihydropyrazino[1,2-a]indole-1,4-dione has been rationally designed, synthesized and evaluated for their antiproliferative activity against a panel of four human cancer cell lines. Compounds 20-23, 28-31, and 33 showed promising antiproliferative activities. These compounds were further tested for their inhibitory potencies against EGFR and BRAFV600E kinases with erlotinib as a reference drug. Compounds 23 and 33 exhibited equipotency to doxorubicin against the four cell lines and efficiently inhibited both EGFR (IC50 = 0.08 and 0.09 µM, respectively) and BRAFV600E (IC50 = 0.1 and 0.29 µM, respectively). In cell cycle study of MCF-7 cell line, compounds 23 and 33 induced apoptosis and exhibited cell cycle arrest in both Pre-G1 and G2/M phases. Molecular docking analyses revealed that the new compounds can fit snugly into the active sites of EGFR, and BRAFV600E kinases. Compound 23, 31 and 33 adopted similar binding orientations and interactions to those of erlotinib and vemurafenib.

Novel class of benzimidazole-thiazole hybrids: The privileged scaffolds of potent anti-inflammatory activity with dual inhibition of cyclooxygenase and 15-lipoxygenase enzymes.

The present study includes design and synthesis of new molecular hybrids of 2-methylthiobenzimidazole linked to various anti-inflammatory pharmacophores through 2-aminothiazole linker, to investigate the effect of such molecular variation on cyclooxygenase (COX) and 15-lipoxygenase (15-LOX) enzymes inhibition as well as in vivo anti-inflammatory activity. The chemical structures of new hybrids were confirmed using different spectroscopic tools and elemental analyses. Benzimidazole-thiazole hybrids linked to acetyl moiety 13, phenyl thiosemicarbazone 14, 1,3-thiazolines 15a-c and 4-thiazolidinone 16 exhibited significant COX-2 inhibition (IC50 = 0.045-0.075 µM) with significant COX-2 selectivity indices (SI = 142-294). All hybrids revealed potent 15-LOX inhibitory activity (IC50 = 1.67-6.56 µM). Benzimidazole-thiazole hybrid 15b was the most potent dual COX-2 (IC50 = 0.045 µM, SI = 294) inhibitor approximate to celecoxib (COX-2; IC50 = 0.045 µM, SI = 327), with double inhibitory activity versus 15-LOX enzyme (IC50 = 1.67 µM) relative to quercetin (IC50 = 3.34 µM). Three hybrids (14, 15b &16) were selected for in vivo screening using carrageenan-induced paw edema method. Benzimidazole-thiazole hybrid linked to 4-thiazolidinone 16 showed the maximum edema inhibition at both 3 h and 4 h intervals as well (~119% and 102% relative to indomethacin, respectively). The gastric ulcerogenic effect of benzimidazole-thiazole hybrid 16 was estimated compared with indomethacin showing superior gastrointestinal safety profile. In bases of molecular modeling; all new active hybrids were subjected to docking simulation into active sites of COX-2 and 15-LOX enzymes to study the binding mode of these novel potent dual COX-2/15-LOX inhibitors.

Novel N-substituted 5-aminosalicylamides as dual inhibitors of cyclooxygenase and 5-lipoxygenase enzymes: Synthesis, biological evaluation and docking study.

Three new series of 5-aminosalicylic acid derivatives; series I (14, 16-18), series II (19-30) and series III (31-41) were synthesized as potential dual COX-2/5-LOX inhibitors. Their chemical structures were confirmed using spectroscopic tools including IR, 1H NMR, 13C NMR, mass spectroscopy and elemental analyses. The anti-inflammatory activity for all target compounds was evaluated in vivo using carrageenan-induced paw edema. Compound 36 showed the highest anti-inflammatory activity (114.12%) relative to reference drug indomethacin at 4 h interval. Selected derivatives were evaluated in vitro to inhibit ovine COX-1, human recombinant COX-2 and 5-LOX enzymes. Compounds 34 &35 exhibited significant COX-2 inhibition (IC50 = 0.10 µM) with significant COX-2 selectivity indices (SI = 135 & 145 respectively) approximate to celecoxib (IC50 = 0.049 µM, SI = 308.16) and exceeding indomethacin (IC50 = 0.51 µM, SI = 0.08). Interestingly, all compounds showed superior 5-LOX inhibitory activity about 2-5 times relative to zileuton. Compound 16 was the superlative 5-LOX inhibitor that revealed (IC50 = 3.41 µM) relative to zileuton (IC50 = 15.6 µM). Compounds 34, 35, 36 and 41 showed significant dual COX-2/5-LOX inhibitions. The gastric ulcerogenic effect of compound 36 was examined on gastric mucosa of albino rats and they showed superior GI safety profile compared with indomethacin. Molecular docking studies of the compounds into the binding sites of COX-1, COX-2 and 5-LOX allowed us to shed light on the binding mode of these novels dual COX and 5-LOX inhibitors.

Design, synthesis, mechanistic and histopathological studies of small-molecules of novel indole-2-carboxamides and pyrazino[1,2-a]indol-1(2H)-ones as potential anticancer agents effecting the reactive oxygen species production.

A series of novel compounds carrying pyrazino[1,2-a]indol-1(2H)-one scaffold (5a-g) and their reaction intermediates, indole-2-carboxamides, (3a-g) were synthesized and evaluated for their ability to inhibit reactive oxygen species (ROS) generation, antioxidant activity and anticancer activity against a panel of cancer cell lines using MTT assay. The results showed that these compounds can inhibit ROS generation during the metabolic phase of phagocytosis in a dose-dependent manner where compounds 5d and 5e were the most potent samples with higher inhibitory activities (IC50 values 3.3 and 1.4 µM, respectively) than that of the reference acetylsalicylic acid (IC50 = 9.7 µM). Results for the determination of potential antioxidant properties of the synthesized compounds showed that compounds 5d and 5e containing pyrazino[1,2-a]indol-1-one backbone were the most acive and even comparable to Trolox. Compounds 3d-f and 5d-f with the least IC50 values in MTT assay were tested against three known anticancer targets EGFR, BRAF and Tubulin. Histopathological and immunohistochemical study were performed to determine the consequence of exposure to chronic low dose of chlorpyrifos on the testis of male mice and results revealed that these effects can be ameliorated by co-treatment with the most active antioxidant compounds 5d and 5e. Finally, molecular docking studies were performed to explore the binding mode of the most active compounds against EGFR and BRAF kinases.

Synthesis and Antimicrobial Evaluation of Some New Thiazoline and Thiazolidinone Derivatives Incorporating [1,2,4]Triazolo[1,5-a]benzimidazole.

Two new series of 3-[2-(3,4-disubstituted-2,3-dihydrothiazol-2-ylidene)hydrazonopropylidenyl]-2-(methylthio)-3H-[1,2,4]triazolo[1,5-a]benzimidazole (6-29) and 3-[2-(3-substituted-4-oxothiazolidin-2-ylidene)hydrazonopropylidenyl]-2-(methylthio)-3H-[1,2,4]triazolo[1,5-a]benzimidazole (30-33) were synthesised starting from 1-[2-(methylthio)-3H-[1,2,4]triazolo[1,5-a]benzimidazol-3-yl] acetone N(4)-alkyl (aryl) thiosemicarbazones (2-5). Chemical structures of the compounds have been elucidated by different spectral data as well as elemental microanalysis. The newly synthesised compounds were tested for their in vitro antimicrobial activity using the standard agar cup diffusion method. Results revealed that most of the test compounds showed promising broad spectrum antibacterial and antifungal profiles against tested microorganisms, relative to references.

Novel 5alpha-reductase inhibitors: synthesis, structure-activity studies, and pharmacokinetic profile of phenoxybenzoylphenyl acetic acids.

Novel substituted benzoyl benzoic acids and phenylacetic acids 1-14 have been synthesized and evaluated for inhibition of rat and human steroid 5alpha-reductase isozymes 1 and 2. The compounds turned out to be potent and selective human type 2 enzyme inhibitors, exhibiting IC(50) values in the nanomolar range. The phenylacetic acid derivatives were more potent than the analogous benzoic acids. Bromination in the 4-position of the phenoxy moiety led to the strongest inhibitor in this class (12; IC(50) = 5 nM), which was equipotent to finasteride. Since oral absorption is essential for a potential drug, 12 was further examined. In the parallel artificial membrane permeation assay (PAMPA) it turned out to be a good permeator, whereas it was a medium permeator in Caco2 cells. After oral administration (40 mg/kg) to rats a high bioavailability and a biological half-life of 5.5 h were observed, making it a promising candidate for clinical evaluation.

Prooxidant and antioxidant action of 4-(4-phenoxybenzoyl)benzoic acid derivatives.

4-(4-Phenoxybenzoyl)benzoic acid derivatives (PBADs) were found to inhibit rat and human alpha-reductase isozymes 1 and 2 in vitro. Chemiluminescence (CL), electron spin resonance, spin trapping techniques, and spectrophotometry were used to examine the effect of PBADs on reactive oxygen species (superoxide radical, O(2)(.-); hydroxyl radical, HO(*); singlet oxygen, (1)O(2)) generating systems. All test compounds at a concentration of 0.5 mM enhanced the CL from O(2)(.-) up to fivefold, which was recorded as the light sums during 1 min. At 0.38 mM PBAD enhanced production of HO(*) from H(2)O(2) in the presence of Co(II) up to 90%, as measured by a deoxyribose assay. Using the spin trap agent 5,5-dimethyl-1-pyrroline-N-oxide, it was found that the amplitude of the signal arising from the Fenton-like reaction [Co(II)/H(2)O(2)] was significantly diminished by the test compounds. The compounds also inhibited the (1)O(2) dependent 2,2,6,6-tetramethylpiperidine-N-oxide radical, which is generated in the acetonitrile/H(2)O(2) system. The measured rate constants of (1)O(2)-dimol quenching by PBAD were in the range of (0.8-2.6) x 10(8) M(-1) s(-1). The interaction between PBAD and (1)O(2) was also checked using a spectrophotometry method based on bleaching of p-nitrosodimethylaniline. These results indicate that PBAD may directly scavenge HO(*) and (1)O(2), but not O(2)(.-). However, the compounds that were examined had prooxidant ability under some reaction conditions.

Cyclohex-1-ene carboxylic acids: synthesis and biological evaluation of novel inhibitors of human 5 alpha reductase.

In search of novel nonsteroidal mimics of steroidal inhibitors of 5 alpha reductase, 4-(2-phenylethyl)cyclohex-1-ene carboxylic acids 1-5 were synthesized with different substituents in para position of the phenyl ring (1: N, N-diisopropylcarbamoyl, 2: phenyl, 3: phenoxy, 4: benzoyl, and 5: benzyl). The principal synthetic approach for the desired compounds consisted of a Wittig olefination between 1, 4-dioxaspiro [4.5]-decane-8-carbaldehyde (4g and the appropriate phosphonium salts. The compounds were tested for inhibition of human 5 alpha reductase isozymes 1 and 2 using DU 145 cells and preparations from prostatic tissue, respectively. They turned out to be good inhibitors of the prostatic isozyme 2 with compound 1 being the most potent one (IC(50) = 760 nM). Isozyme 1 was only slightly inhibited. It is concluded that the novel structures are appropriate for being further optimized, aiming at the development of a novel drug for the treatment of benign prostatic hyperplasia.

Synthesis and biological evaluation of 4-(4-(alkyl- and phenylaminocarbonyl)benzoyl)benzoic acid derivatives as non-steroidal inhibitors of steroid 5 alpha-reductase isozymes 1 and 2.

The synthesis and biological evaluation of 4-(4-(alkyl- and phenylaminocarbonyl)benzoyl)benzoic acids (4a-4d) as non-steroidal inhibitors of steroid 5 alpha-reductase are described. The compounds were tested in vitro for inhibitory activity toward rat and human 5 alpha-reductase isozymes 1 and 2 at a concentration of 10 microM. The most active inhibitor for the human type 2 isozyme was 4-(4-(phenylaminocarbonyl)benzoyl)benzoic acid, compound 4c (IC50 = 0.82 microM).

Synthesis and Biological Evaluation of 4-(4-(Alkyl-and Phenylaminocarbonyl)benzoyl)benzoic Acid Derivatives as Non-steroidal Inhibitors of Steroid 5alpha-Reductase Isozymes 1 and 2.

The synthesis and biological evaluation of 4-(4-(alkyl- and phenylaminocarbonyl)-benzoyl)benzoic acids (4a-4d) as non-steroidal inhibitors of steroid 5alpha-reductase are described. The compounds were tested in vitro for inhibitory activity toward rat and human 5alpha-reductase isozymes 1 and 2 at a concentration of 10 &mgr;M.The most active inhibitor for the human type 2 isozyme was 4-(4-(phenylaminocarbonyl)benzoyl) benzoic acid, compound 4c (IC (50) = 0.82 &mgr;M).

6-Substituted 3,4-dihydro-naphthalene-2-carboxylic acids: synthesis and structure-activity studies in a novel class of human 5alpha reductase inhibitors.

Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5alpha reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1-6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydronaphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7-15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC50 = 0.09 microM, rat type 1), 6-[3-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC50 = 0.75 microM, human type 2; IC50 = 0.81 microM, human type 1) and 6-[4-(N,N-diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC50 = 0.2 microM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki = 90 nM; Km, Testosterone = 0.8-1.0 microM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be ascribed to the relatively poor in vitro rat isozyme inhibitory potency.