Inducible NO synthase confers chemoresistance in head and neck cancer by modulating survivin.
The dual role of the inducible NO synthase (iNOS) and NO signaling in head and neck squamous cell carcinoma (HNSCC) is a complex and can both promote or inhibit tumor progression. However, the underlying molecular mechanisms are not yet resolved in detail. We show for the first time that conditions, favoring low NO levels conferred resistance against cisplatin/taxol-induced apoptosis in HNSCC cell lines. Cytoprotection was mediated by survivin, because we observed its upregulation subsequent to low doses of the NO donors S-nitroso-N-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) or ectopic expression of physiologic amounts of iNOS. Also, RNAi-mediated depletion of survivin blocked NOs anti-apoptotic effects. Induction of survivin involves activation of the phosphatidylinositol-3-kinase/Akt (PI3K/Akt) pathway, which was antagonized by the PI3K-inhibitor LY294002. Importantly, application of the iNOS-specific inhibitor 1400W combined with RNAi-mediated downregulation of survivin cooperatively enhanced drug-induced cell death. The iNOS/survivin-axis appears to be also of clinical relevance since immunohistochemistry revealed that iNOS expression correlated with enhanced survivin levels in HNSCC specimens. In contrast, high NO concentrations suppressed survivin levels in HNSCC but also in non-malignant cells resulting in apoptosis. Cell death induced by high amounts of SNAP/SNP or by strong overexpression of iNOS involved activation of p38MAP-kinase, which was counteracted by the p38MAP-kinase inhibitor SB202190. Here, we provide evidence for a novel molecular mechanism how NO signaling may contribute to therapy resistance in HNSCC by modulating survivin expression. Our data further suggest pursuing pharmacogenetic iNOS/survivin-targeting approaches as potential therapeutic strategies in head and neck cancer.
Fetz
Verena
V
Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Mainz, Germany.
Bier
Carolin
C
Habtemichael
Negusse
N
Schuon
Robert
R
Schweitzer
Andrea
A
Kunkel
Martin
M
Engels
Knut
K
Kovács
Adorján F
AF
Schneider
Sandra
S
Mann
Wolf
W
Stauber
Roland H
RH
Knauer
Shirley K
SK
D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D002945:Cisplatin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005455:Fluorescent Antibody Technique; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D015151:Immunoblotting; D007124:Immunoenzyme Techniques; D051034:Inhibitor of Apoptosis Proteins; D008297:Male; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008875:Middle Aged; D020030:Nitric Oxide Donors / Q000494:pharmacology; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D017239:Paclitaxel / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D000077022:Survivin; D014471:Umbilical Veins / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; C107489:BIRC5 protein, human; D004791:Enzyme Inhibitors; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D020030:Nitric Oxide Donors; D009573:Nitrites; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000077022:Survivin; D009599:Nitroprusside; D026423:S-Nitroso-N-Acetylpenicillamine; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases; D017239:Paclitaxel; D002945:Cisplatin