Activated neutrophils induce prolonged DNA damage in neighboring cells

Abstract

We have measured the capacity of highly-purified, paraffin oil-elicited neutrophils to induce DNA single-strand breaks in a newly established plasmacytoma cell line, RIMPC 2304, which was induced by a retrovirus containing the c-myc and V-Ha-ras oncogenes. This cell line effectively repairs DNA damage induced by gamma-irradiation. DNA damage induced by neutrophils was correlated with the oxidative burst of the neutrophils. The levels of superoxide anion, H2O2, and HOCl produced after stimulation of the neutrophils (6 X 10(5)/cm3) with the tumor promoter phorbol myristate acetate (100 nM) were 33.8 microM, 12.8 microM and 1.7 microM respectively in 15 min, and 98 microM, 20 microM and 8.7 microM respectively in 90 min. The results of alkaline elution experiments revealed that when the same concentration of neutrophils was co-incubated for 15 min in serum-free medium with an equal number of radioactively labeled RIMPC 2304 cells, the latter incurred a level of damage that approximated that caused by 300 rad equivalents of gamma-irradiation or by a 1-min treatment with 20 microM H2O2 at 37 degrees C. Damage from neutrophils was coincident with the oxidative burst; it was induced rapidly (within 5 min) but remained high for more than 90 min. The level of damage achieved was dependent upon the ratio of neutrophils: target cells and was clearly detectable at ratios as low as 0.25:1. Induction of single-strand breaks was completely inhibited by catalase and partially inhibited by superoxide dismutase, mannitol, and reduced glutathione but not by Na azide. Addition of the non-steroidal anti-inflammatory drug indomethacin either enhanced (at 50 microM) or had no effect (at 2 microM) on the damage detected. Finally, repair of strand breaks induced by neutrophils was significantly slower (half-time approximately 10 min) than that observed for repair of similar levels of damage induced by H2O2 or gamma-irradiation (half-times approximately 3 min, each). The results indicate that neutrophils cause prolonged DNA damage in neighboring cells. Moreover, they indicate that although H2O2 produced in the oxidative burst is an essential mediator of the damage observed, additional reactive oxygen intermediates including the superoxide anion are also implicated. The data are discussed in relation to the possible role of neutrophils in chronic inflammation and in pristane-induced plasmacytoma formation in mice.

Neutrophils, Nitric Oxide Synthase, and Mutations in the Mutatect Murine Tumor Model

“…10,18,23,[25][26][27][28][29][30][31] The enzyme responsible for the production of nitric oxide from arginine in tissues is NOS. Immunohistochemical analysis of MN-11 tumors demonstrated iNOS in infiltrating neutrophils and biochemical measurements of tissue extracts showed NOS activity.…”

“…24 The nature of the mutagenic species in the tumor microenvironment is unknown, but is suspected of being reactive oxygen species (ROS) or nitrogen species (RNS). 10,18,23,[25][26][27][28][29][30][31] Because ROS and RNS are known to be mutagenic, it is possible that they are responsible for the genotoxicity associated with both the inflammatory and the tumor microenvironments.…”

DNA damage and repair in tumour and non-tumour tissues of mice induced by nicotinamide

“…One plausible mechanism that could explain these results is that certain normal tissues susceptible to infiltration by phagocytes may accumulate DNA damage via activation of the respiratory burst. Endogenous oxidative stress induced by NAM in phagocytes would then be the mode of action (Shacter et al, 1988;Cochrane, 1991). Support for this hypothesis has been obtained when the size of the spleens from tumour-and nontumour-bearing animals were plotted vs the level of induced DNA damage in the spleens (Figure 6).…”

The causes and prevention of cancer: gaining perspective.

“…The oxidants protect humans from immediate death from infection; but they also cause oxidative damage to DNA, mutation, and chronic cell killing with compensatory cell division (65,66) and thus contribute to the carcinogenic process. Antioxidants appear to inhibit some of the pathology of chronic inflammation (9).…”