Triazolo-linked benzimidazoles as tubulin polymerization inhibitors and DNA intercalators: Design, synthesis, cytotoxicity, and docking studies

A simple click protocol was employed in the quest of synthesizing 1,2,3-triazole-linked benzimidazoles as promising anticancer agents on various human cancer cell lines such as A549, HCT116, SK-Mel-28, HT-29, and MCF-7. Compound 12j demonstrated significant cytotoxic potential towards SK-Mel-28 cancer cells (IC50: 4.17 +/- 0.09 mu M) and displayed no cytotoxicity (IC50: > 100 mu M) against normal human BEAS-2B cells inferring its safety towards normal healthy cells. Further to comprehend the underlying apoptosis mechanisms, AO/EB, dichlorodihydrofluorescein diacetate (DCFDA), and 4',6-diamidino-2-phenylindole (DAPI) staining were performed, which revealed the nuclear and morphological alterations. Compound 12j displayed impairment in cellular migration and inhibited colony formation. The annexin V binding assay and JC-1 were implemented to evaluate the scope of apoptosis and the loss of the mitochondrial transmembrane potential in SK-Mel-28 cells. Cell-cycle analysis revealed that compound 12j arrested the cells at the G2/M phase in a dose-dependent manner. Target-based assays established the inhibition of tubulin polymerization by 12j at an IC50 value of 5.65 +/- 0.05 mu M and its effective binding with circulating tumor DNA as a DNA intercalator. The detailed binding interactions of 12j with tubulin and DNA were examined by docking studies on PDB ID: 3E22 and DNA hexamer (PDB ID: 1NAB), respectively.

Automated summary

A simple click protocol was used to synthesize 1,2,3-triazole-linked benzimidazoles as potential anticancer agents, which showed significant cytotoxicity against SK-Mel-28 cancer cells and no cytotoxicity against normal BEAS-2B cells. Compound 12j inhibited cellular migration, colony formation, and induced apoptosis in SK-Mel-28 cells.