Interferon-alpha induces sensitization of cells to inhibition of protein synthesis by tumour necrosis factor-related apoptosis-inducing ligand.
Tumour cells are often sensitized by interferons to the effects of tumour necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL). We have demonstrated previously that TRAIL has an inhibitory effect on protein synthesis [Jeffrey IW, Bushell M, Tilleray VJ, Morley S & Clemens MJ (2002) Cancer Res62, 2272-2280] and we have therefore examined the consequences of prior interferon-alpha treatment for the sensitivity of translation to inhibition by TRAIL. Interferon treatment alone has only a minor effect on protein synthesis but it sensitizes both MCF-7 cells and HeLa cells to the downregulation of translation by TRAIL. The inhibition of translation is characterized by increased phosphorylation of the alpha subunit of eukaryotic initiation factor eIF2 and dephosphorylation of the eIF4E-binding protein 4E-BP1. Both of these effects, as well as the decrease in overall protein synthesis, require caspase-8 activity, although they precede overt apoptosis by several hours. Interferon-alpha enhances the level and/or the extent of activation of caspase-8 by TRAIL, thus providing a likely explanation for the sensitization of cells to the inhibition of translation.
Jeffrey
Ian W
IW
Translational Control Group, Centre for Molecular and Metabolic Signalling, Division of Basic Medical Sciences, St George's, University of London, UK.
Elia
Androulla
A
Bornes
Stéphanie
S
Tilleray
Vivienne J
VJ
Gengatharan
Karthiga
K
Clemens
Michael J
MJ
D000970:Antineoplastic Agents / Q000494:pharmacology*; D051017:Apoptosis Regulatory Proteins / Q000494:pharmacology*; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects; D004357:Drug Synergism; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D016898:Interferon-alpha; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; C505530:CASP8 protein, human; D053181:Caspase 8; D020169:Caspases