Abstract
Exponentially growing K562 cells incubated with 1-β-d-arabinofuranosylcytosine (ara-C) accumulate ara-C triphosphate (ara-CTP) at a higher rate and to a greater concentration after pretreatment with 9-β-d-ara-binofuranosyl-2-fluoroadenine (F-ara-A) than do cells treated with ara-C alone. Potentiation of ara-C metabolism is due in part to an indirect effect of F-ara-A triphosphate (F-ara-ATP)-mediated reduction in deoxynucleotide pools and consequent activation of deoxycytidine kinase. Because the levels of deoxynucleotide pools and the activity of deoxycytidine kinase are cell cycle-specific, we investigated the effect of cell cycle phases on the accumulation of ara-CTP and the influence of F-ara-A pretreatment on such accumulation. Exponentially growing K562 cells were fractionated into G1, S, and G2+M phase-enriched subpopulations (each enriched by >60%) by centrifugal elutriation. The rate of ara-CTP accumulation was 22, 25, and 14 μm/h and the rate of F-ara-ATP accumulation was 38, 47, and 33 μm/h in the G1, S, and G2+M subpopulations, respectively. The rate of elimination of arabinosyl triphosphates was similar among the different phases of the cell cycle. After pretreatment with F-ara-A, the rate of ara-CTP accumulation in the G1, S, and G2+M phase-enriched subpopulations was 43, 37, and 26 μm/h, indicating a 1.7-, 1.5-, and 1.9-fold increase, respectively. These results suggest that a combination of F-ara-A and ara-C may effectively potentiate ara-CTP accumulation in all phases of the cell cycle. This observation is consistent with the results of studies on the modulation of ara-C metabolism by F-ara-A in lymphocytes and leukemia blasts obtained from patients with chronic lymphocytic leukemia and acute myelogenous leukemia, respectively.
Original language | English (US) |
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Pages (from-to) | 11-17 |
Number of pages | 7 |
Journal | Cancer chemotherapy and pharmacology |
Volume | 31 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1992 |
ASJC Scopus subject areas
- Oncology
- Toxicology
- Pharmacology
- Cancer Research
- Pharmacology (medical)