Novel 1,2,5-Trisubstituted Benzimidazoles Potentiate Apoptosis by Mitochondrial Dysfunction in Panel of Cancer Cells.

Synthetic small molecules have been very effective in decimating cancer cells by targeting various aberrantly overexpressed oncogenic proteins. These small molecules target proteins involved in cell cycle regulation, cell division, migration, invasion, angiogenesis, and other regulatory proteins to induce apoptosis in cancer cells. In this study, we have synthesized a novel 1,2,5-trisubstituted benzimidazole chemical library of small molecules and unveiled their anticancer potential against a panel of cancer cell lines such as Jurkat, K-562, MOLT-4, HeLa, HCT116, and MIA PaCa-2 cancer cells. The MTT assay and Trypan blue dye exclusion assay clearly unveiled the cytotoxic effect of methyl 1-benzyl-2-(4-fluoro-3-nitrophenyl)-1H-benzo[d]imidazole-5-carboxylate (TJ08) and its potential to induce apoptosis with effective IC50 of 1.88 ± 0.51, 1.89 ± 0.55, 2.05 ± 0.72, 2.11 ± 0.62, 3.04 ± 0.8, and 3.82 ± 0.25 µM against Jurkat, K562, MOLT-4, HeLa, HCT116, and MIA PaCa-2 cancer cell lines, respectively. Altered mitochondrial membrane potential was observed in HeLa, HCT116, and Jurkat cells due to TJ08 treatment, which was unveiled by JC10 staining. Induction of early and late apoptosis by TJ08 treatment was also unveiled by apoptotic analysis and immunofluorescence imaging. Cell cycle analysis distribution confirms the accumulation of cells in the S-phase in a dose-dependent manner.

SERS and MD simulation studies of a kinase inhibitor demonstrate the emergence of a potential drug discovery tool.

We demonstrate the use of surface-enhanced Raman spectroscopy (SERS) as an excellent tool for identifying the binding site of small molecules on a therapeutically important protein. As an example, we show the specific binding of the common antihypertension drug felodipine to the oncogenic Aurora A kinase protein via hydrogen bonding interactions with Tyr-212 residue to specifically inhibit its activity. Based on SERS studies, molecular docking, molecular dynamics simulation, biochemical assays, and point mutation-based validation, we demonstrate the surface-binding mode of this molecule in two similar hydrophobic pockets in the Aurora A kinase. These binding pockets comprise the same unique hydrophobic patches that may aid in distinguishing human Aurora A versus human Aurora B kinase in vivo. The application of SERS to identify the specific interactions between small molecules and therapeutically important proteins by differentiating competitive and noncompetitive inhibition demonstrates its ability as a complementary technique. We also present felodipine as a specific inhibitor for oncogenic Aurora A kinase. Felodipine retards the rate of tumor progression in a xenografted nude mice model. This study reveals a potential surface pocket that may be useful for developing small molecules by selectively targeting the Aurora family kinases.