title: Ectopic expression of interferon regulatory factor-1 promotes human breast cancer cell death and results in reduced expression of survivin.
abstract: The overexpression of the inhibitor of apoptosis protein, survivin, may provide tumor cells with a distinct survival advantage in situ; hence, therapeutic strategies have been designed to inhibit its expression. In this study, we ectopically expressed the interferon regulatory factor (IRF)-1 protein in the breast carcinoma cell lines MDA-MB-468 and SK-BR-3 using a recombinant adenovirus (Ad-IRF-1). By screening microarray analysis of cDNA from the human breast cancer cell line MDA-MB-468 infected with Ad-IRF-1, we observed a 15-fold down-regulation of the survivin gene when compared with uninfected cells. Consequently, we tested survivin expression in Ad-IRF-1-infected MDA-MB-468 and SK-BR-3 breast cancer cell lines. Immunoblotting analyses supported the contention that ectopic expression of the IRF-1 protein results in down-regulation of survivin protein expression that is independent of p53. In addition, Ad-IRF-1 infection of these human breast cancer cell lines induces the expression of p21. We also report that increased apoptosis is observed in tumor cells infected with Ad-IRF-1 compared with Ad-Psi5 mock-infected cells and that cell death is further augmented when the IRF-1-infected cells are cultured with Adriamycin. Moreover, in a xenogeneic mouse model of breast carcinoma, in vivo treatment of tumor-bearing mice with intratumoral Ad-IRF-1 injections results in tumor growth inhibition. In resected tumors from mice that had been treated with Ad-IRF-1, tumor cells that express the IRF-1 transgene have a predominant IRF-1-positive, survivin-negative phenotype. Collectively, these observations suggest that therapies designed to enhance IRF-1 expression within tumor cells may represent novel treatment strategies for breast cancer.
authors.affiliation: Department of Medicine, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA. pizzoferatoe@msx.upmc.edu
authors.forename: Eva
authors.initials: E
authors.lastname: Pizzoferrato
authors.forename: Ye
authors.initials: Y
authors.lastname: Liu
authors.forename: Andrea
authors.initials: A
authors.lastname: Gambotto
authors.forename: Michaele J
authors.initials: MJ
authors.lastname: Armstrong
authors.forename: Michael T
authors.initials: MT
authors.lastname: Stang
authors.forename: William E
authors.initials: WE
authors.lastname: Gooding
authors.forename: Sean M
authors.initials: SM
authors.lastname: Alber
authors.forename: Stuart H
authors.initials: SH
authors.lastname: Shand
authors.forename: Simon C
authors.initials: SC
authors.lastname: Watkins
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Storkus
authors.forename: John H
authors.initials: JH
authors.lastname: Yim
mesh_terms: D000818:Animals; D017209:Apoptosis; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004317:Doxorubicin / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D051034:Inhibitor of Apoptosis Proteins; D050856:Interferon Regulatory Factor-1; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009363:Neoplasm Proteins; D010750:Phosphoproteins / Q000378:metabolism*; D000077022:Survivin
chemical_list: C107489:BIRC5 protein, human; D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; D051034:Inhibitor of Apoptosis Proteins; D050856:Interferon Regulatory Factor-1; C494258:Irf1 protein, mouse; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D010750:Phosphoproteins; D000077022:Survivin; D004317:Doxorubicin