NO signaling confers cytoprotectivity through the survivin network in ovarian carcinomas.

Abstract

Despite considerable success in the treatment of epithelial ovarian cancer (EOC), therapy resistance counteracts improvement of long-term survival. The dual role of survivin as an apoptosis inhibitor and mitotic regulator has been associated with disease outcome. However, the molecular mechanisms involved in the deregulated expression in EOC of survivin need further investigation. Here, we show that high amounts of the nitric oxide (NO) donors, S-nitroso-N-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) or strong overexpression of the inducible nitric oxide synthase (iNOS) suppressed survivin levels via the p38MAPK pathway and triggered apoptosis in ovarian cancer cell lines (OCC). Importantly, low NO concentrations conferred resistance against carboplatin/paclitaxel-induced apoptosis. Cytoprotection was mediated by survivin because we observed its up-regulation subsequent to low SNAP/SNP doses or ectopic expression of low amounts of iNOS. Also, RNAi-mediated depletion of survivin blocked the antiapoptotic effects of NO signaling. Induction of survivin involves activation of the phosphatidylinositol-3-kinase (PI3K)/Akt pathway, which was antagonized by the PI3K-inhibitor, LY294002. Interestingly, application of the iNOS-inhibitor 1400W together with RNAi-mediated survivin down-regulation cooperatively enhanced drug-induced apoptosis in OCCs. The iNOS/survivin interdependencies seem to be also of clinical relevance because immunohistochemistry revealed that low iNOS levels correlate with survivin expression (P < 0.01) in carboplatin/paclitaxel-treated EOC patients with minimal postoperative residual tumor (n = 54). Also, iNOS and survivin expression were associated with increased risk for disease progression. Our study uncovers a novel molecular mechanism of how NO signaling may contribute to therapy resistance in EOC by modulating survivin expression. Pharmacogenetic iNOS/survivin-targeting strategies may hence be pursued to complement current treatment modalities in EOC.

• Authors: Knut Engels, Shirley K Knauer, Sibylle Loibl, Verena Fetz, Philipp Harter, Andrea Schweitzer, Annette Fisseler-Eckhoff, Friedrich Kommoss, Lars Hanker, Valentina Nekljudova, Iris Hermanns, Hartmut Kleinert, Wolf Mann, Andreas du Bois, Roland H Stauber
• Journal: Cancer research (Cancer Res) Vol. 68 Issue 13 Pg. 5159-66 (Jul 01 2008) ISSN: 1538-7445 [Electronic] United States
• PMID: 18593915 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• BIRC5 protein, human
• Inhibitor of Apoptosis Proteins
• Microtubule-Associated Proteins
• Neoplasm Proteins
• Survivin
• Nitric Oxide
• NOS2 protein, human
• Nitric Oxide Synthase Type II
• Phosphatidylinositol 3-Kinases
• Oncogene Protein v-akt
• p38 Mitogen-Activated Protein Kinases

Topics

• Antineoplastic Agents (pharmacology)
• Apoptosis (drug effects)
• Carcinoma (genetics, pathology)
• Cell Survival (drug effects)
• Cells, Cultured
• Cytoprotection (drug effects)
• Drug Resistance, Neoplasm (drug effects, genetics)
• Female
• Gene Expression Regulation, Neoplastic
• Gene Regulatory Networks (drug effects, physiology)
• Humans
• Inhibitor of Apoptosis Proteins
• Microtubule-Associated Proteins (genetics, metabolism, physiology)
• Neoplasm Proteins (genetics, metabolism, physiology)
• Nitric Oxide (pharmacology)
• Nitric Oxide Synthase Type II (physiology)
• Oncogene Protein v-akt (metabolism)
• Ovarian Neoplasms (genetics, pathology)
• Phosphatidylinositol 3-Kinases (metabolism)
• Signal Transduction (drug effects)
• Survivin
• p38 Mitogen-Activated Protein Kinases (metabolism, physiology)