Journal Article

Hypochlorous acid/<i>N</i>-chloramines are naturally produced DNA repair inhibitors

Ronald W. Pero, Yezhou Sheng, Anders Olsson, Carl Bryngelsson and Margaretha Lund-Pero

in Carcinogenesis

Volume 17, issue 1, pages 13-18
Published in print January 1996 | ISSN: 0143-3334
e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/17.1.13
Hypochlorous acid/N-chloramines are naturally produced DNA repair inhibitors

More Like This

Show all results sharing this subject:

  • Clinical Cytogenetics and Molecular Genetics

GO

Show Summary Details

Preview

Human mononuclear leukocytes (HML) respond to oxidative DNA damage by activation of ADP ribosylation and initiation of DNA repair synthesis (i.e. unscheduled DNA synthesis, UDS), whereas neutrophils do not. When neutrophils are added to HML cultures in ratios up to 4: 1 ADP ribosylation becomes inhibited to ∼50–60%. The ability of neutrophils to inhibit HML ADP ribosylation was shown to be dependent on H2O2, chloride ions and myeloperoxidase, which in turn are factors known to govern HOCl and N-chloramine production by phagocytic cells. HOCl and a model N-chloramine, chloramine T, were shown to give a dose-dependent inhibition of DNA repair using four independent estimates, namely ADP ribosylation, UDS and the repair of DNA strand breaks estimated by nucleoid sedimentation and alkaline elution profiles. All the DNA repair measurements used on HML were inhibited ∼70–80% by 100 μM doses of HOCl or chloramine T, which was considered a biologically relevant dose because: (i) viable neutrophils equal in concentration to those found in blood could easily produce 100 μM levels in shortterm culture; (ii) 100 μM doses of these agents were not acutely cytotoxic judged by trypan blue stained cells after 30–60 min exposure and under the conditions used for assay, but yet they abolished 86–95% of the growth response of HML to phytohemagglutinin.

Journal Article.  0 words. 

Subjects: Clinical Cytogenetics and Molecular Genetics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.