Antiproliferative and Pro-Apoptotic Effects of Thiazolo[3,2-b][1,2,4]triazoles in Breast and Cervical Cancer Cells.

BACKGROUND AND OBJECTIVES Cancer is one of the leading causes of death in the world affecting millions of people. The commercially available anticancer drugs lack the selectivity and show several undue side effects during the biologically targeted therapy, thus calling for the exploration of wider chemical space to furnish new structural leads with promising anticancer potential. In this endeavor, we synthesized a series of coumarinyl thiazolotriazoles with diverse functional group tolerance and will be tested for their anticancer properties against cancer cell lines (HeLa and MCF-7) and a normal cell line (BHK-21). MATERIALS AND METHODS To overcome such complications, in the current study, we evaluated the cytotoxic effects of coumarinyl thiazolotriazoles hybrids on human breast adenocarcinoma (MCF-7), cervical adenocarcinoma (HeLa) cells and normal cells i.e., baby hamster kidney cells (BHK-21) using MTT (dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide) assay. DNA binding studies of compound 6c was performed on Herring-sperm DNA (HS-DNA) and docking studies were also carried out. The mechanistic studies were performed on potent compounds by fluorescent microscopic studies, release of lactate dehydrogenase (LDH) and mitochondrial membrane potential, activation of caspase-9 and -3 and flow cytometric analysis. RESULTS As revealed by MTT assay, compound 6m and 6c were identified as the most potent derivative among the tested series with IC50 values of 5.64 and 29.1 μM against HeLa and MCF cells, respectively as compared to cisplatin which gave IC50 values of 11.3 and 6.20 μM, respectively. DNA binding studies of compound 6c showed the binding of compound in DNA with Gibbs free energy of ‒17 KJ/mol and docking studies validated the DNA binding studies. Fluorescent microscopic studies using 4',6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI) staining confirmed the occurrence of apoptosis in HeLa cells treated with the most active compound 6m. Moreover, compound 6m and 6c also triggered the release of lactate dehydrogenase (LDH) in treated HeLa and MCF-7 cells while a luminescence assay displayed a remarkable increase in the activity of caspase-9 and -3. Moreover, flow cytometric results revealed that compound 6m caused G0/G1 arrest in the treated HeLa cells. CONCLUSION Our results suggested that the compound possesses chemotherapeutic properties against breast cancer and cervical adenocarcinoma cells, thus warranting further research to test the anticancer efficacy of this compound at clinical level.