Bisindole-Oxadiazole Hybrids, T3P®-Mediated Synthesis, and Appraisal of Their Apoptotic, Antimetastatic, and Computational Bcl-2 Binding Potential

Abstract

In the pursuit of novel anticancer leads, new bisindole-oxadiazoles were synthesized using propyl phosphonic anhydride as a mild and efficient reagent. The molecule, 3-[5-(1H-indol-3-ylmethyl)- 1,3,4-oxadiazol-2-yl]-1H-indole (3a) exhibited selective cytotoxicity to MCF-7 cells with a cell cycle arrest in the G1 phase. The mechanism of cytotoxicity of 3a involved caspase-2-dependent apoptotic pathway with characteristic apoptoticmorphological alterations as observed in acridine orange/ethidium bromide and Hoechst staining. The wound healing migratory assay exhibited an intense impairment in themotility ofMCF-7 cells on incubationwith 3a.Docking simulations with anti-apoptotic protein Bcl-2, which is also involved in cancer metastasis displayed good affinity and high binding energy of 3a into the well characterized BH3 binding site. The positive correlation between the Bcl-2 binding studies and the results of in vitro investigations exemplifies compound 3a as a lead molecule exhibiting MCF-7 differential cytotoxicity via apoptotic mode of cell death in addition to its anti-metastatic activity.