Table 1

Intracellular expression of iNOS and nitrite levels in supernatants of human melanoma cell lines and melanocytes

Cell linesiNOS expressiona (% positive cells)Nitrite levelsb in supernatant (μm)
Mean ± SDRangeMean ± SDRange
Melanoma cell lines (n = 30)60.4 ± 16.935–8733.7 ± 12.420–67
Normal melanocytes (n = 3)94.3 ± 2.192–9559.7 ± 3.858–65
  • a Expression of iNOS was evaluated intracellularly in melanoma cell lines and adult melanocytes by staining with an iNOS-specific mAb after cell permeabilization, followed by cytofluorimetric analysis. Results are expressed as the percentage of positive cells after background subtraction.

  • b Nitrite levels were determined in culture supernatants (1 × 106 cells/ml for 48 h) of neoplastic or normal cells kept in serum-free DMEM. Results are expressed as nitrite concentration (μm).