title: IFN-gamma enhances TRAIL-induced apoptosis through IRF-1.
abstract: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family and a potent inducer of apoptosis. TRAIL has been shown to effectively limit tumor growth in vivo without detectable cytotoxic side-effects. Interferon (IFN)-gamma often modulates the anticancer activities of TNF family members including TRAIL. However, little is known about the mechanism. To explore the mechanism, A549, HeLa, LNCaP, Hep3B and HepG2 cells were pretreated with IFN-gamma, and then exposed to TRAIL. IFN-gamma pretreatment augmented TRAIL-induced apoptosis in all these cell lines. A549 cells were selected and further characterized for IFN-gamma action in TRAIL-induced apoptosis. Western blotting analyses revealed that IFN-gamma dramatically increased the protein levels of interferon regulatory factor (IRF)-1, but not TRAIL receptors (DR4 and DR5) and pro-apoptotic (FADD and Bax) and anti-apoptotic factors (Bcl-2, Bcl-XL, cIAP-1, cIAP-2 and XIAP). To elucidate the functional role of IRF-1 in IFN-gamma-enhanced TRAIL-induced apoptosis, IRF-1 was first overexpressed by using an adenoviral vector AdIRF-1. IRF-1 overexpression minimally increased apoptotic cell death, but significantly enhanced apoptotic cell death induced by TRAIL when infected cells were treated with TRAIL. In further experiments using an antisense oligonucleotide, a specific repression of IRF-1 expression abolished enhancer activity of IFN-gamma for TRAIL-induced apoptosis. Therefore, our data indicate that IFN-gamma enhances TRAIL-induced apoptosis through IRF-1.
authors.affiliation: Bio-Safety Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk, South Korea.
authors.forename: Sang-Youel
authors.initials: SY
authors.lastname: Park
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Seol
authors.forename: You-Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Jong-Hoo
authors.initials: JH
authors.lastname: Cho
authors.forename: Hyung-Sub
authors.initials: HS
authors.lastname: Kang
authors.forename: In-Shik
authors.initials: IS
authors.lastname: Kim
authors.forename: Soo-Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Tae-Hyoung
authors.initials: TH
authors.lastname: Kim
authors.forename: John H
authors.initials: JH
authors.lastname: Yim
authors.forename: Moonil
authors.initials: M
authors.lastname: Kim
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Billiar
authors.forename: Dai-Wu
authors.initials: DW
authors.lastname: Seol
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D050856:Interferon Regulatory Factor-1; D007371:Interferon-gamma / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009841:Oligonucleotides / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D053221:TNF-Related Apoptosis-Inducing Ligand; D013997:Time Factors; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D008562:Membrane Glycoproteins; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; D010750:Phosphoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma