Ectopic expression of interferon regulatory factor-1 promotes human breast cancer cell death and results in reduced expression of survivin.
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.
Pizzoferrato
Eva
E
Department of Medicine, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA. pizzoferatoe@msx.upmc.edu
Liu
Ye
Y
Gambotto
Andrea
A
Armstrong
Michaele J
MJ
Stang
Michael T
MT
Gooding
William E
WE
Alber
Sean M
SM
Shand
Stuart H
SH
Watkins
Simon C
SC
Storkus
Walter J
WJ
Yim
John H
JH
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
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