Human recombinant arginase I(Co)-PEG5000 [HuArgI(Co)-PEG5000]-induced arginine depletion is selectively cytotoxic to human acute myeloid leukemia cells

In this study, we target arginine auxotrophy of AML cell lines using human arginase I cobalt-PEG5000. HuArgI(Co)-PEG5000 was cytotoxic to all AML cell lines tested. Mononuclear cells and CD₃₄⁺ blasts were not sensitive demonstrating the selectivity of HuArgI(Co)-PEG5000-induced arginine deprivation. Addition of l-citrulline led to the rescue of five cell lines. The four cell lines that were not rescued by l-citrulline did not express argininosuccinate synthetase-1, indicating complete arginine auxotrophy. Inhibition of autophagy increased cell sensitivity to HuArgI(Co)-PEG5000 demonstrating the protective role of autophagy following arginine deprivation.