EFFECTS OF NITRIC-OXIDE ON THE ADHESION OF HUMAN MELANOCYTES TO EXTRACELLULAR-MATRIX COMPONENTS

The aim of the present study was to explore whether nitric oxide (NO) interferes with the attachment of human melanocytes to the extracellul ar matrix (ECM) components, Consequently, the effects have been invest igated of the NO-releasing compounds 3-morpholino-sydnonimine (SIN-1) and S-nitroso-ghutathione (GSNO) on the in vitro adhesion of human mel anocytic cells to fibronectin, The NO donors induced a concentration-d ependent reduction in the adhesion of both (CrO42-)-Cr-51-labelled mel anocytes and melanoma cells to fibronectin. Pigmented M14 melanoma cel ls mere more susceptible to the effect of SIN-1 (half-maximal inhibiti ng effect at about 0.5 mM) than normal human melanocytes and also than the non-pigmented melanoma cells Me157 (half-maximal inhibiting effec ts between 0.9 and 2 mM). This effect of SIN-1 also appeared to be rel ated to the melanin content of normal melanocytes, whereas GSNO was si gnificantly less active, Both flow cytometric analysis and immunocytoc hemical staining showed expression of neuronal NO synthase in all cell lines, The results of this study suggest that aberrant in vivo produc tion of NO during infection and inflammation may contribute to loss of melanocytes in, for example, vitiligo, by reducing de novo attachment of melanocytes to the ECM, These findings could also be important for understanding the process of metastasis, (C) 1997 John Wiley & Sons, Ltd.