JDP2 is directly regulated by ATF4 and modulates TRAIL sensitivity by suppressing the ATF4-DR5 axis

Jun dimerization protein 2 (JDP2) is a bZip-type transcription factor, which acts as a repressor or activator of several cellular processes, including cell differentiation and chromatin remodeling. Previously, we found that a stress-responsive transcription factor, known as activating transcription factor 4 (ATF4), enhances JDP2 gene expression in human astrocytoma U373MG and cervical cancer HeLa cells; however, the role of JDP2 in the ATF4-mediated stress response remained unclear. Here, we reported that siRNA-mediated JDP2 knockdown enhances the expression of several ATF4 target genes, including ASNS, and death receptors 4 and 5 (DR4 and DR5) in HeLa cells. In addition, the results of a transient reporter assay indicate that JDP2 overexpression represses ER stress-mediated DR5 promoter activation suggesting that JDP2 negatively regulates ATF4-mediated gene expression. Curiously, knockdown of JDP2 increases the sensitivity of cells to TNF-related apoptosis-inducing ligand (TRAIL), which induces apoptosis in cancer cells through DR4 and DR5. These results indicate that JDP2 functions as a negative feedback regulator of the ATF4 pathway and contributes to TRAIL resistance in cancer cells.