Nitric oxide and caspase 3 mediated cytokine inducedapoptosis in acute leukemia

Abstract

Background: Leukemia is characterized by theuncontrolled accumulation of white blood cells.Recently, cytokines have been used inimmunotherapy, which is a new strategy forleukemia treatment.Objective: To investigate the effect of cytokineson induction of apoptosis in acute leukemic celllines; HL-60, MV4-11, K-562 and Molt-4 andin addition, to study the involvement of nitricoxide (NO) in apoptotic pathways.Methods: Leukemic cell lines were incubatedwith cytokines; interleukin-1β, tumor necrosis factor-α, and interferon-γ in variousconcentrations and for variable periods oftime. The percent apoptosis and caspase 3activation were examined by flow cytometry.Moreover, NO production and inducible nitricoxide synthase (iNOS) mRNA were measuredby using Griess method and Real-time PCR,respectively.Results: Cytokines caused a time and dosedependentinduction of apoptosis in leukemiccell lines. The highest cell apoptosis was foundin K-562 treated with 40 U/ml interferon-γ for48 hours; this correlated with the result of cellgrowth inhibition and caspase 3 activation. NOand iNOS mRNA were increased in cytokinestreated cells. Moreover, apoptosis was reducedby SMT, an iNOS inhibitor, which confirmsthe possible involvement of NO in the apoptoticpathway.Conclusion: Cytokines especially interferon-γ induced apoptosis in acute leukemia via NOand caspase 3 pathway.