Abstract
Ectopic expression of DEP domain containing 1 (DEPDC1) in lung adenocarcinomas is associated with poor prognosis, but its role and the underlying mechanism remain unknown. In this study, DEPDC1 expression in lung cancer cell lines was examined with Western blot assay, and DEPDC1-positive cell A549 was selected for further experiments. DEPDC1 inhibitor miR-130a was overexpressed in A549 cells, and the proliferation and apoptosis of these cells were analyzed with cell counting and flow cytometry assay. Interfering peptide 11R-DEP:611-628 and JNK inhibitor SP600125 were used alone or in combination to treat A549 cells, and the cell proliferation and apoptosis were assessed by flow cytometry assay; caspase 3 and cleaved caspase 3, phosphor-JNK, and total JNK were detected by Western blotting; and nuclear factor kappa B (NF-κB) localization was determined by immunofluorescence staining. We found that miR-130a and 11R-DEP:611-628 peptides (5 μM) both inhibited A549 proliferation and induced apoptosis. We observed that 11R-DEP:611-628 peptide treatment resulted in elevated A20 expression, dramatically reduced nuclear NF-κB, and increased phosphor-JNK. These findings indicate that DEPDC1 inhibits apoptosis of A549 cell by suppressing A20 expression to regulate NF-κB activity, and that JNK plays a protective role upon 11R-DEP:611-628 peptide treatment. In conclusion, DEPDC1 might be a novel therapeutic target for lung cancer, and the 11R-DEP:611-628 peptide is a potent apoptosis inducer in A549 cells.