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

Abstract

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.

Effect of combined arginase and nitric oxide donor treatment on normal and leukemic cells in vitro

“…However, why exogenous NO is more cytotoxic for non-proliferating arginine-deprived than for proliferating in the CM cancer cells remains to be elucidated. It is necessary to stress that similar effect was observed in our previous study on Jurkat cells incubated in defined arginine-free medium [5].…”

“…In our previous study we found that SNP, a NO donor, does not counteract apoptotic cell death and, in fact, increases cytotoxic effect of arginine deprivation for Jurkat leukemic cells in defined arginine-free medium [5]. We also demonstrated that rhARG treatment alone is relatively harmless for normal PBL [4].…”

“…We have chosen one maximally tolerated dose of SNP (0.05 mM) that did not produce any apparent and unacceptable cytotoxicity in both arginine-containing and arginine-free media for normal resting PBL according to the obtained IC 50 values (Table). It is estimated by monitoring nitrite accumulation 0.05 mM SNP releases up to 20-30 µM of NO into the culture medium, the level compatible with physiologically observed in blood plasma (30-70 µM) [5,9].…”

“…Of note, SNP in very low concentrations (below 100 µM) that was proposed as therapeutic dose [5] was non-toxic for resting immune cells.…”

Recombinant arginine‐degrading enzymes in metabolic anticancer therapy and bioanalytics

“…With this respect, we recently observed that deficit of arginine specifically destabilizes actine cytoskeleton in glioma cells and decreases their motility and clonogenic potential (Pavlyk et al, ). It was also found that supplementation of exogenous nitric oxide donor, as a potential attenuating therapeutic compound, does not rescue tumor cells from the effects of arginine deprivation stress (Chen et al, ). Very recent reports also point at a possible ASS role as tumor suppressor (Huang et al, ; Allen et al, ), opening yet new possibilities and stimulating the development of arginine deprivation as an efficient anticancer therapy.…”