1,2,3-Triazole-Chalcone hybrids: Synthesis, in vitro cytotoxic activity and mechanistic investigation of apoptosis induction in multiple myeloma RPMI-8226.

A new series of 1,2,3-triazole-chalcone hybrids has been synthesized and screened in vitro against a panel of 60 human cancer cell lines according to NCI (USA) protocol. Compound 4d having 3, 4-dimethoxyphenyl chalcone moiety, the most potent derivative, inhibited the growth of RPMI-8226 and SR leukemia cell lines by 99.73% and 94.95% at 10 µM, respectively. Also, it inhibited the growth of M14 melanoma, K-562 leukemia, and MCF7 breast cancer cell lines by more than 80% at the same test concentration. 4d showed IC50 values less than 1 µM on six types of tumor cells and high selectivity index reached to 104 fold on MCF7. Compound 4d showed superior activity than methotrexate and gefitinib against the most sensitive leukemia cell lines in addition to higher or comparable activity against the rest sensitive cell lines. Flow cytometry analysis in RPMI-8226 cells revealed that compound 4d caused cell cycle arrest at G2/M phase and induced apoptosis in a dose dependant manner. Mechanistic evaluation referred this apoptosis induction to triggering mitochondrial apoptotic pathway through inducing ROS accumulation, increasing Bax/Bcl-2 ratio and activation of caspases 3, 7 and 9.

Design, synthesis and docking study of novel picolinamide derivatives as anticancer agents and VEGFR-2 inhibitors.

Two series of picolinamide derivatives bearing (thio)urea and dithiocarbamate moieties were designed and synthesized as VEGFR-2 kinase inhibitors. All the new compounds were screened for their cytotoxic activity against A549 cancer cell line and VEGFR-2 inhibitory activity. Compounds 7h, 9a and 9l showed potent inhibitory activity against VEGFR-2 kinase with IC50 values of 87, 27 and 94 nM, respectively in comparison to sorafenib (IC50 = 180 nM) as a reference. Compounds 7h, 9a and 9l were further screened for their antitumor activity against specific resistant human cancer cell lines from different origins (Panc-1, OVCAR-3, HT29 and 786-O cell lines) where compound 7h showed significant cell death in most of them. Multi-kinase inhibition assays were performed for the most potent VEGFR-2 inhibitors where compound 7h showed enhanced potency towards EGFR, HER-2, c-MET and MER kinases. Cell cycle analysis of A549 cells treated with 9a showed cell cycle arrest at G2/M phase and pro-apoptotic activity as indicated by annexin V-FITC staining.

Synthesis, antitumour activities and molecular docking of thiocarboxylic acid ester-based NSAID scaffolds: COX-2 inhibition and mechanistic studies.

A new series of NSAID thioesters were synthesized and evaluated for their in vitro antitumor effects against a panel of four human tumor cell lines, namely: HepG2, MCF-7, HCT-116 and Caco-2, using the MTT assay. Compared to the reference drugs 5-FU, afatinib and celecoxib, compounds 2b, 3b, 6a, 7a, 7b and 8a showed potent broad-spectrum antitumor activity against the selected tumour cell lines. Accordingly, these compounds were selected for mechanistic studies about COX inhibition and kinase assays. In vitro COX-1/COX-2 enzyme inhibition assay results indicated that compounds 2b, 3b, 6a, 7a, 7b, 8a and 8 b selectively inhibited the COX-2 enzyme (IC50 = ∼0.20-0.69 µM), with SI values of (>72.5-250) compared with celecoxib (IC50 = 0.16 µM, COX-2 SI: > 312.5); however, all the tested compounds did not inhibit the COX-1 enzyme (IC50 > 50 µM). On the other hand, EGFR, HER2, HER4 and cSrc kinase inhibition assays were evaluated at a 10 µM concentration. The selected candidates displayed limited activities against the various tested kinases; the compounds 2a, 3b, 6a, 7a, 7b and 8a showed no activity to weak activity (% inhibition = ∼0-10%). The molecular docking study revealed the importance of the thioester moiety for the interaction of the drugs with the amino acids in the active sites of COX-2. The aforementioned results indicated that thioester based on NSAID scaffolds derivatives may serve as new antitumor compounds.

Synthesis, anticancer and apoptosis-inducing activities of quinazoline-isatin conjugates: epidermal growth factor receptor-tyrosine kinase assay and molecular docking studies.

A new series of quinazolinone compounds 16-34 incorporating isatin moieties was synthesized. The antitumor efficacy of the compounds against MDA-MB-231, a breast cancer cell line, and LOVO, a colon cancer cell line, was assessed. Compounds 20, 21, 22, 23, 25, 27, 28, 29, 30, 31, 32, 33, and 34 displayed potent antitumor activity against MDA-MB-231 and LOVO cells (IC50: 10.38-38.67 µM and 9.91-15.77 µM, respectively); the comparative IC50 values for 5-fluorouracil and erlotinib in these cells lines were 70.28 µM, 22.24 µM and 15.23 µM, 25.31 µM respectively. The EGFR-TK assay and induction of apoptosis for compound 31 were investigated to assess its potential cytotoxic activity as a representative example of the novel synthesized compounds. At a concentration of 10 µM, compound 31 exhibited efficient inhibitory effect against EGFR-TK and induced apoptosis in MDA-MB-231 cells. Furthermore, a molecular docking study for compound 31 and erlotinib was performed to verify the binding mode toward the EGFR kinase enzyme, and showed a similar interaction as that with erlotinib alone. Graphical Abstract: Compound 31 showed potent antitumor activity and efficient inhibitory effect against EGFR-TK and induced apoptosis of MDA-MB-231 cells at a concentration of 10 µM.

Design, synthesis, molecular modeling and biological evaluation of novel diaryl heterocyclic analogs as potential selective cyclooxygenase-2 (COX-2) inhibitors.

New series of 3,4-diaryl-2-thioxoimidazolidin-4-ones and 3-alkylthio-4,5-diaryl-4H-1,2,4-triazoles were designed, synthesized and evaluated for their activity as anti-inflammatory agents. Compounds 20, 21, 23 and 34 are highly selective inhibitors of COX-2 enzyme at a concentration of 100 mM relative to celecoxib, the standard reference. (±)-3-(4-Phenoxy-phenyl)-5-phenyl-2-thioxoimidazolidin-4-ones 23 exhibited the most active anti-inflammatory agent.

Synthesis, anti-inflammatory, analgesic, COX-1/2 inhibitory activities and molecular docking studies of substituted 2-mercapto-4(3H)-quinazolinones.

A new series of 2-substituted mercapto-4(3H)-quinazolinone 1-26 were synthesized and assessed for in vivo anti-inflammatory and analgesic activities and in vitro inhibition of cyclooxygenase COX-1/COX-2. A new series of 2-substituted mercapto-4(3H)-quinazolinone 1-26 were synthesized and assessed for in vivo anti-inflammatory and analgesic activities. The potent anti-inflammatory compounds were subjected to in vitro cyclooxygenase COX-1/COX-2 inhibition assays. Compounds 1, 3, 5, 11, 12, 13, 15, 17, and 25 exhibited potent anti-inflammatory effects, with half-maximal effective dose (ED50) values of 65.7-102.4 mg/kg, (0.16-0.36 mmol/kg), and strong analgesic activities, with ED50 values of 33.3-104.6 mg/kg, (0.07-0.34 mmol/kg). These values were compared with those of diclofenac sodium [ED50 values: 112.2 and 100.4 mg/kg, (0.35 and 0.31 mmol/kg)], and celecoxib [ED50 values: 84.3 and 71.6 mg/kg (0.22 and 0.19 mmol/kg)], respectively as reference drugs. Compounds 1, 11, 12, 13, 15, 17, and 25 exhibited effective COX-2 inhibitory activity, with half-maximal inhibitor concentration (IC50) values of 0.70-2.0 µM and selectivity index (SI) values of more than 50-142.9 compared with celecoxib as reference drugs (IC50 = 0.30 µM and COX-2 SI: >333). Potent COX-2 inhibitors, i.e., compounds 15, 11, and 17 were docked into the binding site pockets of COX-1 and COX-2. These compounds exhibited strong interactions at the COX-2 binding site and poor interactions at COX-1 active site pocket.

Design, synthesis of 2,3-disubstitued 4(3H)-quinazolinone derivatives as anti-inflammatory and analgesic agents: COX-1/2 inhibitory activities and molecular docking studies.

A new series, 2-substituted mercapto-3-[2-(pyridin-2-yl)ethyl]-4(3H)-quinazolinone 1-21, was synthesized and evaluated for in vivo anti-inflammatory and analgesic activities and in vitro COX-1/COX-2 inhibition. Compounds 1, 4, 5, 6, 8, 10, 13, 14, 15, 16, and 17 exhibited potent anti-inflammatory and analgesic properties, with ED50 values of 50.3-112.1mg/kg and 12.3-111.3mg/kg, respectively. These values may be compared with those of diclofenac sodium (ED50=112.2 and 100.4mg/kg) and celecoxib (ED50=84.3 and 71.6mg/kg). Compounds 4 and 6 possessed strong COX-2 inhibitory activity with IC50 (0.33µM and 0.40µM, respectively) and selectivity index (SI>303.0 and >250.0, respectively) values that are similar to those of the reference drug celecoxib (IC50 0.30µM and COX-2 SI>333). Compounds 5, 8, and 13 demonstrated effective COX-2 inhibitory activity with IC50 values of 0.70-0.80µM and COX-2 SI>125-142. Potent COX-2 inhibitors, such as compounds 4, 6, and 13, were docked into the active site pockets of COX-1 and COX-2, with the greatest recognition occurring at the COX-2 binding site and insignificant interactions at the binding site of the COX-1 pocket.

Synthesis, anti-inflammatory, analgesic and COX-1/2 inhibition activities of anilides based on 5,5-diphenylimidazolidine-2,4-dione scaffold: Molecular docking studies.

The design, synthesis and pharmacological activities of a group of 5,5-diphenylimidazolidine-2,4-dione bearing anilide, phenacyl and benzylidene fragments 2-27 were reported. The prepared 5,5-diphenylimidazolidine-2,4-dione derivatives were evaluated in vivo for anti-inflammatory, analgesic activities and in vitro for COX-1/2 inhibition assay. Among the tested compounds, derivatives 5, 9, 10, 13, and 14 showed significant and potent anti-inflammatory and analgesic activities almost equivalent to reference drug celecoxib. In COX-1/2 inhibition assay, compounds 5, 9, 10 and 14 showed high COX-2 inhibitory activity (IC50 = 0.70 µM, 0.44 µM, 0.61 µM and 0.41 µM; respectively) and selectivity index (SI) range of 142-243 comparable to celecoxib [COX-2 (SI) > 333]. These potent COX-2 inhibitors 9, 10, 13, and 14 were docked into the active site pocket of COX-2 to explore the binding mode and possible interactions of these ligands.

Thermal stability of G-rich anti-parallel DNA triplexes upon insertion of LNA and α-L-LNA.

G-rich anti-parallel DNA triplexes were modified with LNA or α-L-LNA in their Watson-Crick and TFO strands. The triplexes were formed by targeting a pyrimidine strand to a putative hairpin formed by Hoogsteen base pairing in order to use the UV melting method to evaluate the stability of the triplexes. Their thermal stability was reduced when the TFO strand was modified with LNA or α-L-LNA. The same trend was observed when the TFO strand and the purine Watson-Crick strand both were modified with LNA. When all triad components were modified with α-L-LNA and LNA in the middle of the triplex, the thermal melting was increased. When the pyrimidine sequence was modified with a single insertion of LNA or α-L-LNA the ΔTm increased. Moreover, increasing the number of α-L-LNA in the pyrimidine target sequence to six insertions, leads to a high increase in the thermal stability. The conformational S-type structure of α-L-LNA in anti-parallel triplexes is preferable for triplex stability.

Combating oxidative stress as a hallmark of cancer and aging: Computational modeling and synthesis of phenylene diamine analogs as potential antioxidant.

The cross talk between the over expression of oxygen-free radicals is known as reactive oxygen species (ROS) that is associated with the excessive telomerase activity (TA). Telomerase activity is an invariable finding where human telomerase (hTERT) has been implicated in tumor oxidative stress and redox-mediated malignancy. The hTERT over expression is a novel tumor marker and is promising as a novel class of therapeutic weapons to fight against cancer. A new series of phenylene diamines were designed, synthesized, and evaluated for their in vitro antioxidant as an indicator of inhibiting the oxidative stress tumor. Compounds 3b and 7b proved to be the most active antioxidants with high percentage ABTS inhibition ranged from 89.40% to 88.59% respectively. Molecular modeling studies indicated that the crest configuration of phenylene diamine nucleus with substitutions of trimethoxy benzamido functional proved to be crucial for enhancing the free radical scavenging activity. Molecular modeling exploration indicated the proper binding selectivity of the 3b and 7b to the 3KYL pocket with promising hTERT inhibitors as a hallmark of cancer.

Computational modeling, synthesis, and antioxidant potential of novel phenylcarbamoylbenzoic acid analogs in combating oxidative stress.

A new series of phenylcarbamoylbenzoic acid analogs were designed, synthesized, and evaluated for their in vitro antioxidant activity, aiming to find a lead for the treatment of oxidative stress. The target compounds were prepared by substituting the core phenylcarbamoylbenzoic acid moiety with certain functionalities via simple and efficient synthetic strategies. A molecular modeling study was performed to evaluate the recognition of target compounds at the 3MNG binding pocket. The docking data revealed that compounds 8c and 9a selectively bind to the crucial amino acid residues in the active site of 3MNG. The in vitro antioxidant activity was determined by ABTS antioxidant assay. Compounds 8c, 9a, and 9b showed high antioxidant activity and are thus promising as potent antioxidant leads.

One-pot Synthesis, Molecular Modeling and In Vitro Antibacterial Activity of Novel 3-(1,3,4-Oxadiazol-2-yl) Quinoxaline 1,4-Dioxide and Pyrazolyl Analogs.

The new 1,3,4-oxadiazolylquinoxaline ring system was synthesized by the condensation of the quinoxaline 1,4-dioxide acid hydrazide 6 with acetyl chloride in one-pot synthesis. In which the hydrazide was refluxed in excess of acetyl chloride, acetic anhydride or acetic acid in the presence of phosphorus oxychloride forming the 1,3,4-oxadiazolylquinoxaline ring system. Molecular modeling studies have been performed to evaluate their recognition at the hDHFR binding-pocket as potential hDHFR inhibitors. The antibacterial properties of these compounds showed reasonable activities towards gram negative bacteria, Escherichia coli. Compound 20 performed appropriate complementarity study rather well; the conserved amino acids of hDHFR enzyme imitating the MTX docking pattern. Besides, compound 20 showed highest antibacterial activity against E. coli in comparison with the well known bacteriostatic chloramphenicol; the pyrazolyl analogues also have moderate affinity toward the applied bacteria.

Non-classical antifolates. Part 2: synthesis, biological evaluation, and molecular modeling study of some new 2,6-substituted-quinazolin-4-ones.

A new series of 2,6-substituted-quinazolin-4-ones was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 22, 33-37, 39-43, and 45 proved to be active DHFR inhibitors with IC(50) range of 0.4-1.0microM. Compound 18 showed broad-spectrum antimicrobial activity comparable to the known antibiotic gentamicin. Compounds 34 and 36 showed antitumor activity at GI(50) (MG-MID) concentrations of 11.2, and 24.2microM, respectively. Molecular modeling study including flexible alignment; electrostatic, hydrophobic mappings; and pharmacophore prediction were performed. A main featured pharmacophore model was developed which justifies the importance of the main pharmacophoric groups as well as of their relative distances. The substitution pattern and spatial considerations of the pi-systems in regard to the quinazoline nucleus proved critical for biological activity.

Progesterone inhibition of MDM2 p90 protein in MCF-7 human breast cancer cell line is dependent on p53 levels.

The mdm2 gene encodes several protein isoforms with different molecular weights (p90, p80, p76 and p57). MDM2 p90 (usually considered to be the major MDM2 protein) binds to and inactivates P53. We have recently shown that growth inhibition of MCF-7 human breast cancer cells by progesterone is associated with P53 down-regulation. In this work, we analyzed the expression pattern of MDM2 proteins in three human breast cancer cell lines by western blotting with anti-MDM2 antibodies. We found a prominent expression of MDM2 p57 protein in cell lines which have non-functional P53 protein (T47D and MDA-MB-231) as compared to the p90, p80 isoforms, whereas p90 was the major protein isoform in MCF-7 cells that contain functional P53 protein. When MCF-7 cells were treated with 100 nM of progesterone, MDM2 p90 was inhibited but the highly expressed MDM2 p57 isoform was not. The inhibition of MDM2 p90 protein by progesterone was abrogated in MCF-7 cells transfected with a P53 expressing vector. To our knowledge, this is the first report linking progesterone-induced growth inhibition with down-regulation of the MDM2 protein. We present evidence that reestablishing of P53 expression by transient transfection of P53 cDNA in these cells enhances the expression level of MDM2 p90 isoform. The data indicate that expression of MDM2 p90 is regulated through a P53-dependent pathway in response to progesterone.

Differential recognition of resveratrol isomers by the human estrogen receptor-alpha: molecular dynamics evidence for stereoselective ligand binding.

Resveratrol (RSVL) is a phytoestrogen that occurs naturally in two forms (trans- (E) and cis- (Z)). We have conducted molecular dynamics (MD) studies to differentially characterize the estrogen receptor-alpha (ER-alpha) binding profiles of RSVL stereoisomers. Favorable orientations for RSVL isomers at the ER-alpha pocket were first inferred from (1) alignment with pharmacophoric elements of the pure ER-alpha agonists estradiol (E2) and (2) assessment of ligand recognition by the ER-alpha binding domain. Subsequently, these orientations for RSVL isomers were subjected to MD analyses versus E2. A 100-picosecond MD simulation revealed that E2 contributed four stable hydrogen bonds with the key ER-alpha pocket residue: Arg394, Glu353, His524, and Leu525. Further, E2 displayed favorable binding energy, conformational energy change (DeltaE), and movement of the binding pocket residues (RMSd). Compared to E2, (E)-RSVL lacked a hydrogen bond (HB) with His524 but formed three additional bonds with Gly521, Phe404, and Met343 of the ER-alpha pocket. Further, (E)-RSVL conferred more favorable energy of interaction, less favorable DeltaE, but comparable RMSd values. In contrast, (Z)-RSVL orientations missed hydrogen bonding (HB) with His524 and Leu525, two essential ligand binding residues, and/or produced considerably less favorable-binding energy, -DeltaE, and -RMSd values than did (E)-RSVL. In conclusion, the present study demonstrates the utility of this MD model in distinguishing between RSVL stereoisomers. The weak binding of (Z)-RSVL by the human ER-alpha binding is congruent with its inferior ligand profiles in ER-endowed biological systems. Further, evidence is provided for a considerable variation in the mode of recognition of the mixed agonist/antagonist (E)-RSVL, and the pure agonist E2.

Recognition of resveratrol by the human estrogen receptor-alpha: a molecular modeling approach to understand its biological actions.

OBJECTIVES: Resveratrol (RSVL) is an edible phytoestrogen with multifaceted health benefits that may originate from binding to the estrogen receptors. Despite its structural similarity to the estrogen receptor-alpha (ER alpha) agonist diethylstilbestrol (DES), RSVL showed distinct biological profiles in estrogen-responsive biological systems. The molecular basis of such biological profiles has been undefined. METHODS: We considered possible orientations for RSVL in ER alpha binding pocket. These conformations have been analyzed based on: (i) alignment with the key pharmacophoric elements of DES; (ii) computational energy of interaction, and (iii) pattern of accommodation at the ER alpha binding pocket. The characteristics of the most favored RSVL orientation have been compared with those of DES. RESULTS: Both RSVL and DES interacted with the catalytic amino acid triad of the ER alpha pocket (His524, Arg394 and Glu 353). However, unlike the Er alpha agonists DES and estradiol (E2), RSVL formed three additional hydrogen bonds with Gly521 and Leu525, two paramount ligand recognition residues, and with Met343 at the ER alpha binding cavity. Lastly, RSVL displayed a more favorable energy of interaction with the ER alpha binding cavity. CONCLUSIONS: The present study suggests, for the first time, that RSVL is well recognized by the human ER alpha but in a manner distinct from the pure agonists DES and E2. These variations may well entail the unique biological responses of RSVL in ER-responsive systems.