nitrogen-dioxide and Melanoma

In this article we report inhalation effects of nitrogen dioxide (NO2) and ozone (O3) mixture as well as O3 alone on blood-borne cancer cell colonization of lungs. The findings are discussed in light of our earlier studies with NO2 exposure alone. In all of these studies the mouse B16 melanoma model was used. Animals were exposed to ambient concentrations of pollutants before melanoma-cell infusion. The results have indicated that inhalation of NO2 played a significant role in facilitation of blood-borne cancer cell spread, while O3 inhalation did not. With respect to mechanisms involved, the role of natural immunity was investigated and its was postulated that nitrogen dioxide may affect cells of the immune system and may in part account for the results. These findings may have direct bearing on dissemination of human cancer cells, since many cancer patients have circulating cancer cells and are exposed daily to noxious air pollutants. Most importantly, this effect may be preventable by reducing air pollution in urban areas.

Topics: Air Pollutants; Animals; Cell Line; Cytotoxicity, Immunologic; Lung Neoplasms; Male; Melanoma; Mice; Neoplastic Cells, Circulating; Nitrogen Dioxide; Ozone; Spleen

A study was carried out to determine the interrelationship between the inhalation of nitrogen dioxide (0.4 +/- 0.50 ppm), lung metastases development from circulating cancer cells, and death rate from such metastases. C57 BL/6J mice were used in these experiments. Animals were divided into control and NO2-exposed groups, and were exposed to filtered air and 0.4 ppm of NO2, respectively. Following 12 weeks of exposure, all animals were infused intravenously with syngeneic, viable B16 melanoma cells. The results indicate that a subpopulation of NO2-exposed animals showed a significant increase in mortality rate during the early part of the experiment. The interpretation is that animals especially sensitive to the NO2 insult developed extensive metastases at an early stage. The question raised is whether or not the progression of human cancer is influenced by the inhalation of noxious pollutants in the ambient atmosphere.

Topics: Air Pollutants; Animals; Cocarcinogenesis; Disease Susceptibility; Lung Neoplasms; Male; Melanoma; Mice; Mice, Inbred C57BL; Neoplastic Cells, Circulating; Nitrogen Dioxide

Studies have been carried out to determine whether the inhalation of ambient levels of nitrogen dioxide (NO2), a common air pollutant, could influence the frequency of blood-borne cancer cell metastasis to the lungs. B16 mouse melanoma cells were used as an in vivo test model. the results have indicated that animals inhaling ambient levels of NO2 developed a significantly higher number of melanoma nodules in their lungs than the animals inhaling filtered air. Thus, a new concept for the action of air pollutants is proposed. The question is raised whether similar events are taking place in urban human populations.

Topics: Air Pollutants; Animals; Humans; Lung Neoplasms; Melanoma; Mice; Mice, Inbred C57BL; Nitrogen Dioxide; Urban Health

An experimental model was designed to test the possibility that inhalation of a noxious air pollutant may facilitate the blood-borne cancer cell metastasis to the lungs. Animals were exposed to inhalation of air containing 0.8 ppm of nitrogen dioxide for 12 weeks. After this period, animals were infused intravenously with melanoma cells, and 3 weeks later lungs were examined for metastases. The results indicate that NO2exposed animals develop significantly higher number of lung metastases (P less than 0.0025) than the controls. Such results raise the possibility that the inhalation of NO2 from ambient air may facilitate the seeding and proliferation of blood-borne cancer cells in the human lung.

Topics: Air Pollutants; Animals; Cell Line; Humans; Lung Neoplasms; Melanoma; Mice; Neoplasms, Experimental; Neoplastic Cells, Circulating; Nitrogen Dioxide