title: Bortezomib pre-treatment prolongs interferon-alpha-induced STAT1 phosphorylation in melanoma cells.
abstract: Bortezomib is a proteasome inhibitor that can synergize with interferon-alpha (IFN-alpha) to induce apoptosis in melanoma cells in vitro and inhibit tumor growth in vivo. We hypothesized that proteasome inhibition may be an effective means to sensitize melanoma cells to the direct effects of IFN-alpha. Pre-treatment of human melanoma cells with bortezomib led to significantly increased transcription of interferon-stimulated genes as determined by real-time PCR. Flow cytometric and immunoblot analyses indicated that the enhanced direct actions of IFN-alpha on melanoma cells were the result of prolonged phosphorylation of STAT1 (P-STAT1) on both the Tyrosine(701) and Serine(727) residues. In contrast, the enhanced IFN-alpha-induced P-STAT1 was not observed in peripheral blood mononuclear cells that were pre-treated with bortezomib. These data suggest that proteasome inhibition represents a mechanism to enhance the direct effects of IFN-alpha on melanoma cells thereby complementing its immunostimulatory properties.
authors.affiliation: Division of Hematology and Oncology, Department of Internal Medicine, Arthur G. James Cancer Hospital, Richard J. Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA. gregory.lesinski@osumc.edu
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Lesinski
authors.forename: Kristen
authors.initials: K
authors.lastname: Benninger
authors.forename: Melanie
authors.initials: M
authors.lastname: Kreiner
authors.forename: Megan
authors.initials: M
authors.lastname: Quimper
authors.forename: Gregory
authors.initials: G
authors.lastname: Young
authors.forename: William E
authors.initials: WE
authors.lastname: Carson
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D001897:Boronic Acids / Q000008:administration & dosage / Q000494:pharmacology*; D000069286:Bortezomib; D045744:Cell Line, Tumor; D004357:Drug Synergism; D006801:Humans; D007370:Interferon Type I / Q000008:administration & dosage / Q000494:pharmacology*; D053612:Janus Kinases / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D008545:Melanoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D061988:Proteasome Inhibitors; D011719:Pyrazines / Q000008:administration & dosage / Q000494:pharmacology*; D011994:Recombinant Proteins; D050794:STAT1 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D001897:Boronic Acids; D007370:Interferon Type I; D061988:Proteasome Inhibitors; D011719:Pyrazines; D011994:Recombinant Proteins; D050794:STAT1 Transcription Factor; D000069286:Bortezomib; D053612:Janus Kinases