engleski

The role of PMNs in melanoma B16-F10 growth

While it is well known that polymorphonuclear neutrophils (PMNs) play an essential role in host defence against micro organisms, mechanisms by which PMNs may also cause immune reactions against cancer are not well understood. It is assumed that oxidative damage caused by reactive oxygen species (ROS) from activated PMNs may contribute to the pathology of tumours. ROS have been identified as effector molecules in the mechanisms of oxygen dependent killing of cancer cells by PMNs. Therefore, the aim of our work was to monitor the oxidative burst and anti-tumour activities of murine PMNs in respect to the tumour development from the early phase to the advanced stages in an experimental model. Mice were injected with melanoma B16-F10 i.m. and/or with Sephadex G-200 s.c. Sephadex causes an aseptic inflammation absorbing in a subcutaneously formed papula activated PMNs and inflammatory exudates. Significantly enlarged spleen was observed in tumour-treated and Sephadex injected mice. Histopathologic analysis of spleen and liver tissue revealed haematopoiesis with prominent neutrophil presence. Intensive oxidative burst was determined by luminol amplified chemiluminescence of PMA activated peripheral blood cells of Sephadex treated mice. Data were compared with percentage of peripheral blood PMNs in respect to control animals and their treatment. The PMNs from papula developed at the site of Sephadex injection diminished tumour cell proliferation in vitro (measured by 3H-TdR incorporation assay). However, survival of Sephadex injected tumour bearing mice was lower than of control animals bearing B16-F10, while their tumours grew faster and were less necrotic. It is therefore likely that injection of Sephadex draws the neutrophils away from the tumour, allowing faster progression of tumour. The obtained results indicate that neutrophils may have an important role in the host defence against malignant cells in the early stage of tumour development.

PMNs; melanoma

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