The HDAC1 Inhibitor CBUD-1001 Enhances TRAIL-induced Apoptosis in Colorectal Cancer Cells.

Abstract

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential anti-tumor agent. However, resistance to TRAIL has been reported in a number of clinical trials. In this study, we investigated the molecular mechanisms by which a novel histone deacetylase (HDAC) inhibitor, CBUD-1001, sensitizes colorectal cancer (CRC) cells to TRAIL-induced apoptosis. Apoptotic cell death induced by CBUD-1001 and/or TRAIL was assessed on human CRC cells using the MTT assay, FACS analysis and nuclei staining. The involved molecular mechanisms were explored through western blotting analysis. We demonstrated that combined with CBUD-1001, TRAIL significantly enhanced TRAIL-induced apoptosis in CRC cells via mitochondria-mediated pathways. We also found that hyper-acetylation of histone by CBUD-1001 treatment leads to up-regulation of death receptor (DR) 5 in a dose- and time-dependent manner. Furthermore, we identified that enhanced sensitivity to TRAIL by combination with CBUD-1001 depends on the MAPK/CHOP axis, being a key mediator of DR5. A novel HDAC inhibitor CBUD-1001 sensitizes TRAIL-induced apoptosis via up-regulation of DR5, and that CBUD-1001 and TRAIL combination treatment offers an effective strategy to overcome TRAIL resistance in CRC cells.