Hypoxic Inducible Factor 1 α, Extracellular Signal-Regulated Kinase, and p53 Are Regulated by Distinct Threshold Concentrations of Nitric Oxide

NO produced in tumors can either positively or negatively regulate growth. To examine this dichotomy, effects of NO concentration and duration on the posttranslational regulation of several key proteins were examined in human breast MCF7 cells under aerobic conditions. We found that different concen...

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Published inProceedings of the National Academy of Sciences - PNAS Vol. 101; no. 24; pp. 8894 - 8899
Main Authors Thomas, Douglas D., Espey, Michael Graham, Ridnour, Lisa A., Hofseth, Lorne J., Mancardi, Daniele, Harris, Curtis C., Wink, David A., Ignarro, Louis J.
Format Journal Article
LanguageEnglish
Published National Academy of Sciences 15.06.2004
National Acad Sciences
Subjects
Biological Sciences
Cancer
Cell growth
Cell lines
Hypoxia
Macrophages
Phosphorylation
Physiological regulation
Signal transduction
Stromal cells
Tumors
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Summary:NO produced in tumors can either positively or negatively regulate growth. To examine this dichotomy, effects of NO concentration and duration on the posttranslational regulation of several key proteins were examined in human breast MCF7 cells under aerobic conditions. We found that different concentration thresholds of NO appear to elicit a discrete set of signal transduction pathways. At low steady-state concentrations of NO (<50 nM), extracellular signal-regulated kinase (ERK) phosphorylation was induced via a guanylate cyclase-dependent mechanism. Hypoxic inducible factor 1α (HIF-1α) accumulation was associated with an intermediate amount of NO (>100 nM), whereas p53 serine 15 phosphorylation occurred at considerably higher levels (>300 nM). ERK phosphorylation was transient during NO exposure. HIF-1α stabilization paralleled the presence of NO, whereas p53 serine 15 phosphorylation was detected during, and persisted after, NO exposure. The dose-dependent effects of synthetic NO donors were mimicked by activated macrophages cocultured with MCF7 cells at varying ratios. ERK and HIF-1α activation was similar in breast cancer cell lines either mutant (MB231) or null (MB157) in p53. The stabilization of HIF-1α by NO was not observed with increased MCF7 cell density, demonstrating the interrelationship between NO and O2consumption. The findings show that concentration and duration of NO exposure are critical determinants in the regulation of tumor-related proteins.
Bibliography:To whom correspondence may be addressed at: Radiation Biology Branch, National Institutes of Health/National Cancer Institute, Building 10, Room B3-B69, Bethesda, MD 20892. E-mail: wink@box-w.nih.gov or thomasdo@mail.nih.gov.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: iNOS, inducible NO synthase; ERK, extracellular signal-regulated kinase; pERK, p42 and p44 ERK; HIF-1α, hypoxic inducible factor 1α; Sper/NO, spermine NONOate; Dea/NO, diethylamine NONOate; Deta/NO, diethyltryamine NONOate; P-Ser-15, phosphoserine 15.
Edited by Louis J. Ignarro, University of California School of Medicine, Los Angeles, CA, and approved April 27, 2004
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.0400453101