Vitamin c inhibits apoptosis induced byoxidative stress in hl-60 myeloid leukemia cells

B. Witenberg*, H. Kalir, V. Kravstov, Z. Raviv, I. Fabian

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The human myeloid leukemia cell line HL-60 transports the oxidized form of ascorbic acid, dehydroascorbic acid (DHA) and accumulates reduced ascorbic acid. We studied the effect of ascorbate loading on apoptosis induced by serum - and glucose-free culture and oxidative stress induced by H202. Uptake accumulation studies indicate that incubation of HL-60 cells in the presence of DHA (50nM or 150nM) for 15 min, resulted in the accumulation of intracellular concentrations of 0. 74 ±0. 12 mM and 8. 6 ±1. 5 mM ascorbic acid, respectively. A marked decrease in intracellular ascorbic acid concentration occurred with time when ascorbate-loaded cells were incubated in DMA-free medium. Subsequent to an incubation period of 8 hr, intracellular ascorbic acid concentration decreased to 35% and 60% respectively of the zero time concentrations. Exposure of HL-60 cells to increasing concentrations of H202 resulted in intracellular accumulation of peroxides, as determined by the use of the oxidation-sensitive fluorescent probe 2',7'-dichlorofluorescin diacetate, which was dose dependent and was accompanied by a decrease in intracellular ascorbic acid. A dramatic decrease in intracellular ascorbate was noted when preloaded HL-60 cells were exposed to 1 SOM H2O2. Following exposure of the cells to H202 for 8 hr, no ascorbic acid could be detected in cells preloaded with 50M DHA, while the intracellular concentration of ascorbic acid dropped from 5. 2 ±0. 6 mM to 3. 6 ±0. 1 mM in cells preloaded with 150nM DHA. Exposure of HL-60 cells to H2O2 resulted in an increased percentage of apoptotic cells which was dose and time dependent. A dose-dependent protective effect of DHA was observed following ascorbate loading of HL-60 cells. Ascorbate loading also provided strong protection from apoptosis associated with serum- and glucose-free culture. These findings indicate that ascorbic acid can inhibit apoptosis induced by oxidative stress in HL-60 cells.

Original languageEnglish
Pages (from-to)755
Number of pages1
JournalExperimental Hematology
Volume25
Issue number8
StatePublished - 1997

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