2-deoxy-D-ribose-induced apoptosis in HL-60 cells is associated with the cell cycle progression by spermidine

The presence of polyamines is required for the apoptotic program triggered by a-deoxy-D-ribose (dRib) in HL-60 cells, but their oxidative metabolites does not appear to be involved in the oxidative stress caused by the sugar. The present study points to a relationship between spermidine-induced G(1) to S phase transition and the onset of dRib-induced apoptosis. Conversely, the G(1) block induced by alpha-difluoromethylornithine (DFMO) is associat ed with a protective effect against dRib-induced cell suicide. Replenishmen t of the intracellular spermidine pool by exogenous putrescine and spermidi ne induces cell cycle progression and restores apoptotic levels. The presen t data indicate that the induction of cell cycle progression by spermidine is a condition facilitating the activation of the apoptotic process by dRib . (C) 1999 Academic Press.