The Journal of Neuroscience, April 1, 2009, 29(13):4189-4199; doi:10.1523/JNEUROSCI.5747-08.2009
Previous Article | Next Article 
Neurobiology of Disease
BNIP3 (Bcl-2 19 kDa Interacting Protein) Acts as Transcriptional Repressor of Apoptosis-Inducing Factor Expression Preventing Cell Death in Human Malignant Gliomas
Teralee R. Burton,1,4
David D. Eisenstat,1,2,3,4 and
Spencer B. Gibson1,4
Departments of 1Biochemistry and Medical Genetics, 2Pediatrics and Child Health, and 3Human Anatomy and Cell Science, and 4Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Manitoba, Canada R3E 0V9
Correspondence should be addressed to Dr. Spencer B. Gibson, Manitoba Institute of Cell Biology, 675 McDermot Avenue, Winnipeg, Manitoba, Canada R3E 0V9. Email: gibsonsb{at}cc.umanitoba.ca
The Bcl-2 19 kDa interacting protein (BNIP3) is a pro-cell-death BH3-only member of the Bcl-2 family. We previously found that BNIP3 is localized to the nucleus in the majority of glioblastoma multiforme (GBM) tumors and fails to induce cell death. Herein, we have discovered that nuclear BNIP3 binds to the promoter of the apoptosis-inducing factor (AIF) gene and represses its expression. BNIP3 associates with PTB-associating splicing factor (PSF) and HDAC1 (histone deacetylase 1) contributing to transcriptional repression of the AIF gene. This BNIP3-mediated reduction in AIF expression leads to decreased temozolomide-induced apoptosis in glioma cells. Furthermore, nuclear BNIP3 expression in GBMs correlates with decreased AIF expression. Together, we have discovered a novel transcriptional repression function for BNIP3 causing reduced AIF expression and increased resistance to apoptosis. Thus, nuclear BNIP3 may confer a survival advantage to glioma cells and explain, in part, why BNIP3 is expressed at high levels in solid tumors, especially GBM.
Received Dec. 2, 2008;
revised Jan. 26, 2009;
accepted Feb. 12, 2009.
Correspondence should be addressed to Dr. Spencer B. Gibson, Manitoba Institute of Cell Biology, 675 McDermot Avenue, Winnipeg, Manitoba, Canada R3E 0V9. Email: gibsonsb{at}cc.umanitoba.ca