Article (Scientific journals)
The acidic tumor microenvironment promotes the reconversion of nitrite into nitric oxide: towards a new and safe radiosensitizing strategy
Frérart, Françoise; Sonveau, Pierre; Rath, Géraldine et al.
2008In Clinical Cancer Research, 14 (9), p. 2768-2774
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Abstract :
[en] PURPOSE: The biological status of nitrite recently evolved from an inactive end product of nitric oxide catabolism to the largest intravascular and tissue storage of nitric oxide (NO). Although low partial O(2) pressure favors enzymatic reconversion of nitrite into NO, low pH supports a nonenzymatic pathway. Because hypoxia and acidity are characteristics of the tumor microenvironment, we examined whether nitrite injection could preferentially lead to NO production in tumors and influence response to treatments. EXPERIMENTAL DESIGN: The effects of nitrite were evaluated on arteriole vasorelaxation, tumor cell respiration and tumor blood flow, oxygenation, and response to radiotherapy. RESULTS: We first showed that a small drop in pH (-0.6 pH unit) favored the production of bioactive NO from nitrite by documenting a higher cyclic guanosine 3',5'-monophosphate-dependent arteriole vasorelaxation. We then documented that an i.v. bolus injection of nitrite to tumor-bearing mice led to a transient increase in partial O(2) pressure in tumor but not in healthy tissues. Blood flow measurements failed to reveal an effect of nitrite on tumor perfusion, but we found that O(2) consumption by nitrite-exposed tumor cells was decreased at acidic pH. Finally, we showed that low dose of nitrite could sensitize tumors to radiotherapy, leading to a significant growth delay and an increase in mouse survival (versus irradiation alone). CONCLUSIONS: This study identified low pH condition (encountered in many tumors) as an exquisite environment that favors tumor-selective production of NO in response to nitrite systemic injection. This work opens new perspectives for the use of nitrite as a safe and clinically applicable radiosensitizing modality.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Frérart, Françoise
Sonveau, Pierre
Rath, Géraldine
Smoos, Alexandra
Meqor, Ahlam
Charlier, Nicolas
Jordan, Bénédicte F.
Saliez, Julie
Noël, Agnès ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Biologie cellulaire et moléculaire appliquée à l'homme
Dessy, Chantal
Gallez, Bernard
Feron, Olivier
Language :
English
Title :
The acidic tumor microenvironment promotes the reconversion of nitrite into nitric oxide: towards a new and safe radiosensitizing strategy
Publication date :
2008
Journal title :
Clinical Cancer Research
ISSN :
1078-0432
eISSN :
1557-3265
Publisher :
American Association for Cancer Research, Inc. (AACR), Birmingham, United States - Alabama
Volume :
14
Issue :
9
Pages :
2768-2774
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 21 December 2009

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