BioProject

Clinical applications of human interferon (IFN)-alpha have met with varying degrees of success. More...

Clinical applications of human interferon (IFN)-alpha have met with varying degrees of success. Nevertheless, key molecules in IFN-alpha-induced cell death have not been clearly identified. Our previous study indicated that IFN (alpha, beta and omega) receptor (IFNAR) 1/2- and IFN regulatory factor (IRF) 9-RNA interference (RNAi) completely inhibited the antiproliferative (AP) activity of IFN-alpha in human ovarian adenocarcinoma OVCAR3 cells sensitive to IFN-alpha., followed by transcription of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Here, IFNAR1/2- and IRF9-RNAi inhibited the gene expression of TRAIL, but not of Fas ligand (FasL), following IFN-alpha treatment. In fact, TRAIL but not FasL inhibited the proliferation of OVCAR3 cells. IFN-alpha notably up-regulated the levels of TRAIL protein in the supernatant and on the membrane of OVCAR3 cells. Following TRAIL signaling, Caspase 8 inhibitor and BH3 interacting domain death agonist (BID)-RNAi significantly abrogated both AP activities of IFN-alpha and TRAIL. Furthermore, BID-RNAi prevented both IFN-alpha and TRAIL from collapsing the mitochondrial membrane potential (Delta Psi m). Finally, we provide important new evidence that BID overexpression led to a major enhancement of both AP activities of IFN-alpha and TRAIL in human lung carcinoma A549 cells resistant to IFN-alpha. Thus, this study suggests that BID is crucial in IFN-alpha-induced cell death, indicating a notable potential to be a targeted therapy for IFN-alpha resistant tumors. Overall design: Biological replicate samples were created by treating OVCAR3 cells with IFN-alpha2c (n=8); IFNAR1-RNAi and IFN-alpha2c (n=4); IFNAR2-RNAi and IFN-alpha2c (n=5); ISGF3gamma-RNAi and IFN-alpha2c (n=3); and Negative RNAi and IFN-alpha2c (n=3). For analysis, the eight IFN-alpha2c treated OVCAR3 samples were paired with an untreated OVCAR3 control sample. The 15 RNAi treated OVCAR3 samples were paired with a Negative RNAi control sample. Less...