Synthesis, biological evaluation and molecular docking studies of 2-amino-3,4,5-trimethoxyaroylindole derivatives as novel anticancer agents

Novel Indole-Pyrazole Hybrids as Potential Tubulin-Targeting Agents; Synthesis, antiproliferative evaluation, and molecular modeling studies

Structurally diverse indole-3-pyrazole-5-carboxamide analogues (10-29) were designed, synthesized, and evaluated for their antiproliferative activity against three cancer cell lines (Huh7, MCF-7, and HCT116) using the sulforhodamine B assay. Some of the derivatives showed anticancer activities equal to or better than sorafenib against cancer cell lines. Compounds 18 showed potent activity against the hepatocellular cancer (HCC) cell lines, with IC50 values in the range 0.6-2.9 μM. Compound 18 also exhibited moderate inhibitory activity against tubulin polymerization (IC50 = 19 μM). Flow cytometric analysis of cultured cells treated with 18 also demonstrated that the compound caused cell cycle arrest at the G2/M phase in both Huh7 and Mahlavu cells and induced apoptotic cell death in HCC cells. Docking simulations were performed to determine possible modes of interaction between 18 and the colchicine site of tubulin and quantum mechanical calculations were performed to observe the electronic nature of 18 and to support docking results.

Structural Investigations of Aroylindole Derivatives through 3D-QSAR and Multiple Pharmacophore Modeling for the Search of Novel Colchicines Inhibitor

Background :

The ligand and structure based integrated strategies are being repeatedly and effectively employed for the precise search and design of novel ligands against various disease targets. Aroylindole derivative has a similar structural analogy as Combretastatin A-4, and exhibited potent anticancer activity on several cancer cell lines.

Objective:

To identify structural features of aroylindole derivatives through 3D-QSAR and multiple pharmacophore modelling for the search of novel colchicines inhibitor via virtual screening.

Method:

The present study utilizes ligand and structure based methodology for the establishment of structure activity correlation among trimethoxyaroylindole derivatives and the search of novel colchicines inhibitor via virtual screening. The 3D-QSAR studies were performed using Phase module and provided details of relationship between structure and biological activity. A single ligand based pharmacophore model was generated from Phase on compound 3 and compound 29 and three energetically optimized structure based pharmacophore models were generated from epharmacophore for co-crystallized ligand, compound 3 and compound 29 with protein PBD ID 1SA0, 5EYP and 5LYJ. These pharmacophoric features containing hit-like compounds were collected from commercially available ZINC database and screened using virtual screening workflow.

Results and Discussion:

The 3D-QSAR model studies with good PLSs statistics for factor four was characterized by the best prediction coefficient Q2 (0.8122), regression R2 (0.9405), SD (0.2581), F (102.7), P (1.56e-015), RMSE (0.402), Stability (0.5411) and Pearson-r (0.9397). The generated epharmacophores have GH scores over 0.5 and AUAC ≥ 0.7 indicated that all the pharmacophores were suitable for pharmacophore-based virtual screening. The virtual screened compounds ZINC12323179, ZINC01642724, and ZINC14238006 have showed similar structural alignment as co-crystallized ligand and showed the hydrogen bonding of ligand with ASN101, SER178, THR179, VAL238, CYS241 amino acid of protein.

Conclusion:

The study illustrates that the ligand and structure based pharmacophoric approach is beneficial for identification of structurally diverse hits, having better binding affinity on colchicines binding site as novel anticancer agents.

Iridium- and Rhodium-Catalyzed Directed C-H Heteroarylation of Benzaldehydes with Benziodoxolone Hypervalent Iodine Reagents

The C-H heteroarylation of benzaldehydes with indoles and pyrroles was realized using the benziodoxolone hypervalent iodine reagents indole- and pyrroleBX. Functionalization of the aldehyde C-H bond using either an o-hydroxy or amino directing group and catalyzed by an iridium or a rhodium complex allowed the synthesis of salicyloylindoles and (2-sulfonamino)benzoylindoles, respectively, with good to excellent yields (74-98%). This new transformation could be carried out under mild conditions (rt to 40 °C) and tolerated a broad range of functionalities, such as ethers, halogens, carbonyls, or nitro groups.

Novel 1,2,4-triazole derivatives as potential anticancer agents: Design, synthesis, molecular docking and mechanistic studies

A series of novel compounds carrying 1,2,4-triazole scaffold was synthesized and evaluated for their anticancer activity against a panel of cancer cell lines using MTT assay. Compounds 8a, 8b, 8c, 8d, 10b, 10e, and 10 g showed remarkable antiproliferative activity against the tested cell lines. Compounds 8a, 8b, 8c, 8d, 10b, 10e, and 10 g with the least IC₅₀ values in MTT assay were tested against three known anticancer targets including EGFR, BRAF and Tubulin. The results revealed that compounds 8c and 8d showed almost same BRAF inhibitory activity and were discovered to be potent inhibitors of cancer cell proliferation and were also observed to be strong Tubulin inhibitors. Moreover, 8c also showed the best EGFR inhibition with IC₅₀ = 3.6 μM. Finally molecular modeling studies were performed to explore the binding mode of the most active compounds to the target enzymes.

Development of combretastatins as potent tubulin polymerization inhibitors

The combretastatins are isolated from South African tree combretum caffrum kuntze. The lead compound combretastatin A-4 has displayed remarkable cytotoxic effect in a wide variety of preclinical tumor models and inhibits tubulin polymerization by interacting at colchicine binding site of microtubule. However, the structural simplicity of C A-4 is favorable for synthesis of various derivatives projected to induce rapid and selective vascular shutdown in tumors. Majority of the molecules have shown excellent antiproliferative activity and are able to inhibit tubulin polymerization as well as possible mechanisms of action have been investigated. In this review article, the synthesis and structure-activity relationships of C A-4 and immense number of its synthetic derivatives with various modifications on the A, B-rings, bridge carbons and their anti mitotic activities are discussed.

Design, synthesis, and biological evaluation of novel alkylsulfanyl-1,2,4-triazoles as cis-restricted combretastatin A-4 analogues

Thirty-two novel 3-alkylsulfanyl-1,2,4-triazole derivatives, designed as cis-restricted combretastatin A-4 analogues, were synthesized and evaluated for their antiproliferative activities. The results indicated that analogue 20 showed more potent antiproliferative activities against PC-3 cell lines than positive control CA-4. Particularly, the most promising compound 25 displayed 5-fold improvement compared to CA-4 in inhibiting HCT116 cell proliferation with IC₅₀ values of 1.15 μM. Further flow-activated cell sorting analysis revealed that compound 20 displayed a significant effect on G₂/M cell-cycle arrest in a dose-dependent manner in PC-3 cells. From this study, analogues 20 and 25 were the most potent anti-cancer agents in this structural class, and were considered lead compounds for further development as anti-cancer drugs.