ABSTRACT
As pyrazole and isoxazole based derivatives are well-known for displaying a considerable biological profile, an attempt has been made to unravel their cytotoxic potential. In this context, a number of pyrazole/isoxazole linked arylcinnamide conjugates (15a-o and 21a-n) have been synthesized by employing a straight forward route. The basic structure comprised three ring scaffolds (A, B and C): methoxyphenyl rings as A and C rings and a five membered heterocyclic ring (pyrazole or isoxazole) as the B-ring. To achieve clear understanding, these derivatives are categorized as pyrazole-phenylcinnamides (PP) and isoxazole-phenylcinnamides (IP). These compounds have been evaluated for their ability to inhibit the growth of various human cancer cell lines such as HeLa, DU-145, A549 and MDA-MB231 and most of them exhibit considerable cytotoxic effects. Some of them like 15a, 15b, 15e, 15i and 15l exhibit promising cytotoxicity in HeLa cells (IC50 = 0.4, 1.8, 1.2, 2.7 and 1.7 µM). Amongst them 15a, 15b and 15e were taken up for detailed biological studies, they were found to arrest the cells in the G2/M phase of the cell cycle. Moreover, they were investigated for their effect on the microtubular cytoskeletal system by using a tubulin polymerization assay, immunofluroscence and molecular docking studies; interestingly they demonstrate a significant inhibition of tubulin polymerization.
Subject(s)
Antineoplastic Agents/pharmacology , Cinnamates/pharmacology , Drug Design , Isoxazoles/pharmacology , Pyrazoles/pharmacology , Tubulin Modulators/pharmacology , Tubulin/metabolism , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cinnamates/chemistry , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , HeLa Cells , Humans , Isoxazoles/chemistry , Molecular Structure , Polymerization/drug effects , Pyrazoles/chemistry , Structure-Activity Relationship , Tubulin Modulators/chemical synthesis , Tubulin Modulators/chemistryABSTRACT
A series of twenty one compounds with pyrazole and oxindole conjugates were synthesized by Knoevenagel condensation and investigated for their antiproliferative activity on different human cancer cell lines. The conjugates are comprised of a four ring scaffold; the structural isomers 12b and 12c possess chloro-substitution in the D ring. Among the congeners 12b, 12c, and 12d manifested significant cytotoxicity and inhibited tubulin assembly. Treatments with 12b, 12c and 12d resulted in accumulation of cells in G2/M phase, disruption of microtubule network, and increase in cyclin B1 protein. Zebrafish screening revealed that 12b, and 12d caused developmental defects. Docking analysis demonstrated that the congeners occupy the colchicine binding pocket of tubulin.
