Effect of nitric oxide donor on viability of human leukemic cells upon arginine deprivation

Some types of tumor cells are unable to synthesize arginine from its precursors. They exhibit growth inhibition and decreased viability in vitro and in vivo under enzymatic arginine deprivation. However, prolonged arginine starvation in human may cause vasoconstriction and thrombosis due to the deficit of arginine derivative, nitric oxide (NO), as vasodilator and disaggregant. This problem can be overcome via supplementation with exogenous NO-donors in vivo, which, in turn, may produce either, pro-apoptotic or anti-apoptotic specific effects on cancer cells under arginine restriction. In this study we elucidated the effect of exogenous NO donor, sodium nitroprusside (SNP) on the viability of human Jurkat leukemic cells under arginine deprivation in vitro. We observed that arginine deprivation suppressed cell proliferation and led to a rapid decrease in cell viability concomitant with progression of apoptosis. According to SNP IC50 determination and apoptosis assays, NO-donor at physiological concentration did not promote survival of tumor cells in arginine-free medium. Moreover, SNP cytotoxicity for Jurkat cells was increased upon arginine withdrawal, suggesting that application of NO donor in vivo may potentially enhance the therapeutic effect of arginine deprivation