title: Interferon-alpha sensitizes human hepatoma cells to TRAIL-induced apoptosis through DR5 upregulation and NF-kappa B inactivation.
abstract: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, induces apoptosis in a variety of cancer cells with little or no effect on normal cells. Human hepatoma cells, however, are resistant to TRAIL-induced apoptosis. Since interferon-alpha (IFN-alpha) is capable of enhancing TNF-alpha-induced apoptosis in certain cancer cells, we evaluated the effect of IFN-alpha on TRAIL-induced apoptosis of human hepatoma cells. IFN-alpha pretreatment enhanced TRAIL-induced apoptosis of HuH-7 and Hep3B cells, in which IFN-alpha upregulated the expression of DR5, a death receptor of TRAIL, and downregulated the expression of survivin, which has an antiapoptotic function. In contrast, IFN-alpha did not enhance TRAIL-induced apoptosis of HepG2 cells, in which expression of DR5 and survivin was not affected by IFN-alpha. On the other hand, TRAIL activated NF-kappa B composed of RelA-p50 heterodimer, a key transcription factor regulating cell survival, in HuH-7 and HepG2 cells. However, IFN-alpha pretreatment repressed the TRAIL-mediated activation of NF-kappaB and decreased its transcriptional activity in HuH-7 but not in HepG2 cells. Moreover, IFN-alpha pretreatment clearly augmented TRAIL-mediated caspase-8 activation in HuH-7 cells. Our results suggest that IFN-alpha could sensitize certain human hepatoma cells to TRAIL-induced apoptosis by stimulating its death signaling and by repressing the survival function in these cells.
authors.affiliation: First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Shigeno
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakao
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Kasumi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawakami
authors.forename: Seigou
authors.initials: S
authors.lastname: Abiru
authors.forename: Seiji
authors.initials: S
authors.lastname: Miyazoe
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hamasaki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nakata
authors.forename: Nobuko
authors.initials: N
authors.lastname: Ishii
authors.forename: Katsumi
authors.initials: K
authors.lastname: Eguchi
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology*; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D017931:DNA Primers; D015536:Down-Regulation; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D016898:Interferon-alpha / Q000494:pharmacology*; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000235:genetics; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D009363:Neoplasm Proteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology*; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*; D015854:Up-Regulation
chemical_list: D051017:Apoptosis Regulatory Proteins; C107489:BIRC5 protein, human; D017931:DNA Primers; D051034:Inhibitor of Apoptosis Proteins; D016898:Interferon-alpha; D008562:Membrane Glycoproteins; D008869:Microtubule-Associated Proteins; D016328:NF-kappa B; D009363:Neoplasm Proteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand; C505639:TNFRSF10B protein, human; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases