Polyamine depletion protects HL-60 cells from 2-deoxy-D-ribose-induced apoptosis

We investigated the involvement of natural polyamines in HL-60 cell death triggered by exposure to 2-deoxy-D-ribose (dRib). In contrast to previous studies, exogenous polyamines failed to protect HL-60 cells against apoptosis caused by dRib. Moreover, in our experimental conditions, depletion of intracellular levels of putrescine and spermidine by alpha-difluoromethylornithine (DFMO) delayed the onset of apoptosis by at least a day or so. Exogenous polyamines reversed the beneficial effect of DFMO and restored the apoptotic levels observed in dRib-treated cells. We suggested that polyamines, especially putrescine and spermidine, act as facilitating factors in the induction of apoptosis triggered by dRib in HL-60 cells.