Nitric oxide level and expression of iNOS increase in de novo acute myeloid leukaemia blasts and HL 60 cells

Nitric oxide is an important mediator, which has several roles in both physiological and pathological processes. In this study, we aimed to determine the level of nitrite and nitrate levels representing NO and expression of iNOS in HL 60 model cell line during the differentiation and cytoplasmic extract of blastic cells obtained from 20 de novo AML patients to evaluate any correlation between nitrite and nitrate levels and various prognostic factors and the possible role of NO in leukaemogenesis. Griess method was used to determine the level of nitrite and nitrate. Western blotting was performed by using iNOS expression with polyclonal anti-iNOS antibody. Higher nitrate and nitrite levels were found in HL60 cells before differentiation and in patients compared to control group. When HL 60 cells were treated with methylprednisolone, the level of nitrite and nitrate decreased gradually during differentiation. And also, there was detectable amount of iNOS protein expression in HL60 cells and in patients but not in control samples. Although we could not provide the data related to changes in neither expression level of iNOS nor the amount of nitrite and nitrate after treatment in patients, our findings suggests the possible role of NO in leukaemogenesis. Copyright © Hellenic Society of Haematology.