FIG. 2.

Neuronal NOS (nNOS) expression is elevated in melanoma compared to normal melanocytes. (A) Immunoblotting assay of human primary melanocytes and melanoma cell lines. (B) Immunoblotting assay of mouse melanoma cell lines (F4280B, F5061, and F5127) and mouse melanocytes (MMC). (C) Immunohistochemistry analysis of nNOS expression levels using melanoma tissue array. Positive cells were visualized by light microscope and at least 10 highlight fields of each sample were examined. (D) Increased nNOS stainings in melanoma biopsies were significantly correlated with disease stages. Immunohistochemistry (IHC) staining score was determined by the average percentage of cells positive for nNOS: 0, 0%–5%; 1, 6%–30%; 2, 31%–59%; and 3, >60%. The number of samples in normal, T2N0M0, T3N0M0, and T4N0M0 were 23, 3, 9, and 10, respectively. *p<0.05 compared to normal skin tissue. (E, F) nNOS expression is markedly induced by UVA (E) or UVB (F) radiation in human melanoma cells. The represented data were done in wm3211 cells. (G, H) Basic fibroblast growth factor (10 ng/ml) treatment stimulated nNOS expression in immortalized human melanocytes, but DETA/NO incubation and UVB radiation failed to induce nNOS levels in normal Caucasian melanocytes. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars