Survivin interacts with Smac/DIABLO in ovarian carcinoma cells but is redundant in Smac-mediated apoptosis

McNeish, I. A., Lopes, R., Bell, S. J., McKay, T. R., Fernandez, M., Lockley, M., Wheatley, S. P. and Lemoine, N. R. (2005) Survivin interacts with Smac/DIABLO in ovarian carcinoma cells but is redundant in Smac-mediated apoptosis. Experimental Cell Research, 302 (1). pp. 69-82. ISSN 0014-4827

Full text not available from this repository.

Abstract

Abnormalities in the control and execution of apoptosis are seen in many malignancies, including ovarian carcinoma. Many of these abnormalities involve the mitochondrial pathway of apoptosis, including overexpression of BIR-containing inhibitor of apoptosis protein (IAP) family proteins as well as dysregulated apoptosome function. We sought to stimulate the mitochondrial pathway of apoptosis by constructing a recombinant adenovirus encoding mature, processed Smac/DIABLO (Ad CMV tSmac), the second mitochondrial activator of caspases. Transfection of ovarian carcinoma cells with Ad CMV tSmac leads to increasing apoptosis in a dose-dependent manner. By contrast, transfection of IOSE397 immortalized normal ovarian surface epithelial cells does not cause apoptosis. We also show that the processed form of Smac is primarily expressed in the cytosol of ovarian carcinoma cells. Smac co-immunoprecipitates with both survivin and XIAP and stimulates survivin, but not XIAP, down-regulation. This down-regulation does not result from transcriptional changes, as determined by quantitative real-time PCR, but cycloheximide treatment indicates that survivin half-life is reduced from 6 to 2 h, which is secondary to ubiquitination and proteasomal degradation. RNA interference, however, suggests that survivin does not act to inhibit Smac-mediated apoptosis, which is confirmed by cotransfection with the phosphorylation mutant, survivin T34A. Finally, intraperitoneal delivery of Ad CMV tSmac increases median survival of mice bearing human ovarian carcinoma xenografts. We believe that expression of Smac/DIABLO can stimulate the intrinsic pathway of apoptosis in ovarian carcinoma without damaging normal ovarian tissue and therefore has therapeutic potential.

Item Type: Article
Additional Information: 0014-4827 (Print) Journal Article GDSC154
Keywords: Apoptosis/*genetics Carcinoma/genetics/*metabolism/therapy Carrier Proteins/genetics/*metabolism/pharmacology Caspases/metabolism Cell Line, Tumor Dose-Response Relationship, Drug Down-Regulation/genetics Epithelial Cells/drug effects/metabolism Female Gene Therapy/methods Genetic Vectors/genetics/pharmacology Humans Injections, Intraperitoneal Intracellular Signaling Peptides and Proteins Microtubule-Associated Proteins/genetics/*metabolism Mitochondria/genetics/metabolism Mitochondrial Proteins/genetics/*metabolism/pharmacology Neoplasm Proteins Ovarian Neoplasms/genetics/*metabolism/therapy Proteasome Endopeptidase Complex/genetics Protein Synthesis Inhibitors/pharmacology Proteins/metabolism Research Support, Non-U.S. Gov't Survival Rate Up-Regulation/genetics X-Linked Inhibitor of Apoptosis Protein
Depositing User: Gee Wheatley
Date Deposited: 19 Mar 2007
Last Modified: 15 Jun 2012 10:36
URI: http://sro.sussex.ac.uk/id/eprint/934
Google Scholar:43 Citations
📧 Request an update