title: Thioredoxin reductase plays a critical role in IFN retinoid-mediated tumor-growth control in vivo.
abstract: The IFN and retinoic acid (RA) combination suppresses cell growth by inducing apoptosis in the cultured tumor cells. Using a genetic technique, we have isolated several "genes associated with retinoid-IFN-induced mortality" (GRIM) that participate in this death pathway. One such gene, GRIM-12, encodes the redox enzyme thioredoxin reductase (TR). Antisense-mediated inhibition of TR abrogates cell death. To test the in vivo relevance of TR for growth suppression, we have conducted the following study. A wild-type TR or a catalytically defective mutant were expressed in MCF-7 breast carcinoma cells and transplanted into athymic nude mice. These mice were treated with IFN-beta and all-trans RA combination. Tumors expressing the vector or wild-type TR were readily suppressed by the IFN/RA combination. In contrast, the tumors bearing a mutant TR were resistant to regression. We further show that markers of apoptosis are stimulated in the regressing tumors. These studies show a prominent role for TR in tumor-growth suppression.
authors.affiliation: Greenebaum Cancer Center, Department of Microbiology and Immunology, Molecular and Cellular Biology Program, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Lindner
authors.forename: Xinrong
authors.initials: X
authors.lastname: Ma
authors.forename: Jiadi
authors.initials: J
authors.lastname: Hu
authors.forename: Sreenivasu
authors.initials: S
authors.lastname: Karra
authors.forename: Dhananjaya V
authors.initials: DV
authors.lastname: Kalvakolanu
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D015153:Blotting, Western; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D015536:Down-Regulation; D004789:Enzyme Activation; D005260:Female; D015870:Gene Expression; D006801:Humans; D016899:Interferon-beta / Q000494:pharmacology*; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D016297:Mutagenesis, Site-Directed; D009368:Neoplasm Transplantation; D013880:Thioredoxin-Disulfide Reductase / Q000502:physiology*; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D017304:Annexin A5; D000970:Antineoplastic Agents; D014212:Tretinoin; D016899:Interferon-beta; D013880:Thioredoxin-Disulfide Reductase; C505530:CASP8 protein, human; C506433:CASP9 protein, human; C505526:Casp8 protein, mouse; C506434:Casp9 protein, mouse; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases