Synthesis and biological evaluation of benzamide-chalcone hybrids as potential c-Met kinase and COX-2 inhibitors.

c-Met kinase and cyclooxygenase 2 (COX-2) enzymes are two significant targets in tumor progression. Chalcone and benzamide moieties were combined using molecular hybridization to assess their potential as c-Met kinase and COX-2 inhibitors. 4-Methylbenzamide and 4-chlorobenzamide chalcone analogs were synthesized, characterized, and evaluated for antiproliferative activity on Michigan Cancer Foundation-7 (MCF-7), HT-29, MDA-MB-231, COLO-205, and A549 cell lines by sulforhodamine-B stain (SRB) assay. Following the SRB assay, compounds were evaluated for their c-Met kinase and COX-2 inhibitory potential. All compounds inhibited COX-2 with half-maximal inhibitory concentration (IC50 ) <10 µM. Compounds 7h, 7i, 7j, 8f, and 8j inhibited c-Met with IC50 <10 µM. Compound 7h was evaluated for its long-term antiproliferative and anti-migratory effects by colony formation and wound healing assay. It exerted these effects in a concentration-dependent manner. Compounds 7j and 8j were further evaluated for in vitro antiangiogenic effects. Compound 7j exhibited moderate antiangiogenic effect while compound 8j exhibited strong effect. Compounds 7h, 7i, 7j, 8f, and 8j were evaluated for the serum protein binding, using the in vitro bovine serum albumin binding assay. The results indicated that the tested compounds bind to bovine serum albumin (BSA) and can be further explored by other studies.

Evaluation of Benzamide-Chalcone Derivatives as EGFR/CDK2 Inhibitor: Synthesis, In-Vitro Inhibition, and Molecular Modeling Studies.

BACKGROUND: EGFR (Epidermal Growth Factor Receptor) and CDK2 (Cyclin Dependent Kinase 2) are important targets in the treatment of many solid tumors and different ligands of these receptors share many common structural features. OBJECTIVE: The study involved the synthesis of benzamide-substituted chalcones and determination of their antiproliferative activity as well as a preliminary evaluation of EGFR and CDK2 inhibitory potential using both receptor binding and computational methods. METHODS: We synthesized 13 benzamide-substituted chalcone derivatives and tested their antiproliferative activity against MCF-7, HT-29 and U373MG cell lines using Sulforhodamine B Assay. Four compounds were examined for activity against EGFR and CDK2 kinase. The compounds were docked into both EGFR and CDK2 using Glide software. The stability of the interactions for the most active compound was evaluated by Molecular Dynamics Simulation using Desmond software. Molecular docking studies on mutant EGFR (T790M, T790M/L858R, and T790M/C797S) were also carried out. RESULTS: From the SRB assay, we concluded that compounds 1g, and 1k were effective in inhibiting the growth of the MCF-7 cell line whereas the other compounds were moderately active. Most compounds were either moderately active or inactive on U373 MG and HT-29 cell lines. Compounds 1g and 1k showed good inhibitory activity against CDK2 kinase while 1d and 1f were moderately active. Compounds 1d, 1f, 1g, and 1k were moderately active against EGFR kinase. Molecular docking reveals the involvement of one hydrogen bond with Met793 in binding with EGFR; however, it was not stable during the simulation and these compounds bind to the receptor mainly via hydrophobic contacts. This fact also points towards a different orientation of the inhibitor within the active site of EGFR kinase. Binding mode analysis for CDK2 inhibition studies indicates that hydrogen bonding interactions with Lys 33 and Leu83 are important for the activity. These interactions were found to be stable throughout the simulation. Considering the results for wild-type EGFR inhibition, the docking studies on mutants were performed and which indicate that the compounds bind to the mutant EGFR but the amino acid residues involved are similar to the wild-type EGFR, and therefore, the selectivity seems to be limited. CONCLUSION: These benzamide-substituted chalcone derivatives will be useful as lead molecules for the further development of newer inhibitors of EGFR and/or CDK2 kinases.

Studies in molecular modeling, in-vitro CDK2 inhibition and antimetastatic activity of some synthetic flavones.

Naturally occurring flavonoids have been shown to possess anticancer activity. We have previously shown that certain synthetic flavonoids also exert significant antiproliferative potential in MOLT-4, MCF-7, and HepG2 cell lines. To this end, we evaluated eight synthetic flavones for their CDK2 binding by molecular docking. Most flavones showed interaction with Leu 83. Based on docking and antiproliferative activity, we chose 3'-nitroflavone and 3', 5'-dimethoxyflavone for the molecular dynamics (MD) simulation and CDK2 inhibition studies. MD simulation studies confirmed interactions with CDK2 (as observed in docking). Furthermore, the inhibitory activities of CDK2/cyclin A2 enzyme for 3'-nitroflavone and 3', 5'-dimethoxyflavone were found to be 6.17 and 7.19 �M, respectively. 3'-nitroflavone and 3', 5'-dimethoxyflavone displayed moderate activity in colony formation assay, wound-scratch assay, and Leighton tube studies. Based on these data, the synthesized flavones might have clinical potential as potential inhibitors of CDK2.

Pharmacophore and Docking Guided Virtual Screening Study for Discovery of Type I Inhibitors of VEGFR-2 Kinase.

BACKGROUND: Kinase domain of VEGFR-2 displays conformational flexibility which leads to existence of two kinds of inhibitors viz. type I and type II inhibitors. They exhibit different binding modes and this necessitates the development of separate pharmacophore models for them. METHODS: The virtual screening study for discovery of type I inhibitors of VEGFR-2 kinase was done by using combined pharmacophore (generated using PHASE and validated by 3D-QSAR) and docking (Glide) based approach. Validated pharmacophore was used as preliminary filter followed by docking. ADME properties were predicted for retrieved hits using QikProp. RESULTS: ADHRR.94 with statistical parameters r2 test 0.94, r2 training 0.99, SD 0.0766, r2 0.9861, F 283.3, RMSE 0.2605, q2 0.8115 and Pearson's R 0.9723was identified as the best pharmacophore hypothesis for type I inhibitors of VEGFR-2 kinase. Virtual screening study was done for Asinex Elite Libraries comprising of 104400 molecules using ADHRR.94, HTVS docking and XP docking that resulted in twelve hits. Asinex ligand 5686 with docking score of -10.48kcal/mol was top-ranking hit. It made two hydrogen bonding interactions with Cys 919, one as an acceptor and other as a donor, which are characteristic of type I inhibitors. Additional interactions observed were π-cation with Lys 868 and π- πstacking with Phe 1047.Twelve hits had acceptable values for ADME properties. CONCLUSION: Twelve hits with best obtained docking scores ranging from -10.48 to -7.23 kcal/mol and mimicking characteristic type I inhibitor interactions were identified which could be probable inhibitors of VEGFR-2.

Localization and interaction of hydroxyflavones with lipid bilayer model membranes: a study using DSC and multinuclear NMR.

The localization and interaction of six naturally occurring flavones (FLV, 5HF, 6HF, 7HF, CHY and BLN) in DPPC bilayers were studied using DSC and multi-nuclear NMR. DSC results indicate that FLV and 6HF interact with alkyl chains. The (1)H NMR shows interaction of flavones with the sn-glycero region. Ring current induced chemical shifts indicate that 6HF and BLN acquire parallel orientation in bilayers. 2D NOESY spectra indicate partitioning of the B-ring into the alkyl chain region. The DSC, NMR and binding studies indicate that 5HF and 7HF are located near head group region, while 6HF, CHY and BLN are located in the vicinity of sn-glycero region, and FLV is inserted deepest in the membrane.

In-vitro anti-proliferative and anti-oxidant activity of galangin, fisetin and quercetin: role of localization and intermolecular interaction in model membrane.

Flavonols are an important class of naturally occurring molecules and are known for their pharmacological activity. The activity is associated with the ability of flavonols to influence membrane-dependent processes. We have investigated the in-vitro anti-proliferative and anti-oxidant activity of galangin (GLN), fisetin (FTN) and quercetin (QTN), which possess variable number of phenolic hydroxyl groups. An attempt has been made to correlate the biological activity of these molecules with their interaction and localization in dipalmitoyl phosphatidyl choline (DPPC) bilayers, using differential dcanning calorimetry (DSC) and nuclear magnetic resonance (NMR) methods. Results indicate that GLN interacts to the alkyl chains of the lipid bilayer involving hydrophobic interactions. FTN and QTN interact with head region and sn-1-glycero region involving hydrogen bonding. Ring current induced chemical shifts of lipid protons, due to intermolecular interaction indicate that GLN acquires a parallel orientation with respect to the bilayer normal whereas FTN and QTN resume a mixed orientation. The membrane binding constants of these molecules are in the order GLN > QTN > FTN. It has been shown that the number and position of hydroxyl groups in these molecules play an important role in membrane binding and thereby in biological activity.

Synthesis, characterisation and antitumour activity of some quercetin analogues.

Quercetin is one of the most abundant naturally occurring flavonoid and is associated with a wide range of biological activities, such as antioxidant, antiinflammatory and anticancer activities. However, there are multiple problems associated with the bioavailability of quercetin, thereby restricting its use. Taking this into consideration, the structure of quercetin was modified by removal of multiple hydroxyl groups and introduction of substituents such as Cl, OCH3 and N (CH3)2 on the p-position of the B-ring. The effect of structural modification on the anticancer activity was studied using four different cell lines, including MCF-7, HepG2, HCT-15 and PC-3. Compound 1a has shown an activity better than quercetin in HepG2 cell lines, whereas 1c and 1e showed significant growth inhibition of the HCT-15 cell lines.

A simple HPLC method for quantitation of quercetin in herbal extracts.

A reversed-phase HPLC method with UV detection was developed for the determination of quercetin. The method produced linear response over a wide concentration range, with an average accuracy of 95% and average intra- and interday variation of 0.75 and 0.3, respectively. The exactness of the method was proven by determining the recovery rates from 50 to 150% of standard concentration, which were found within the acceptable range of 95 to 105%. The method was used for quantitation of quercetin in the extracts of Psidium guajava, Vitis vinifera, and extracts rich in quercetin and other flavonols in the flavonoid family.