PRODUCTION OF SUPEROXIDE BY HUMAN-MALIGNANT MELANOMA-CELLS

Metastasis is a complicated multi-step process involving interactions between tumour cells, the extracellular matrix and the vessel walls. E xperimental observations suggest that leucocyte migration and function could be a suitable model in order to understand tumour cell dissemin ation, In the present report we show and quantify the production of fr ee radicals by human malignant melanoma cells (St-ml12) by means of a spectrophotometrical method, using an enzyme immunoassay reader. Endot helial cells and activated polymorphonuclear leucocytes were used as c ontrols, Melanoma cells without stimulants produced large amounts of s uperoxide anion at an increasing rate in relation to time, which could be inhibited by superoxide dismutase. Production of hydrogen peroxide was minimal. The endothelial cells produced a negligible amount, in c ontrast to the activated polymorphonuclear leucocytes, which released large quantities of both free radicals. A rapid assay to analyse the p roduction of free radicals by tumour cells is presented here. Using th is, we demonstrated that melanoma cells produce superoxide anions, sup porting previous observations which implicate superoxide anion in the mechanism of metastasis. (C) 1998 Lippincott Williams & Wilkins.