G1-PHASE ARREST OF CULTURED HUMAN-LEUKEMIC T-CELLS INDUCED BY DEOXYADENOSINE

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (12) , 5141-5150
Abstract
Cultured human T-cell leukemic lymphocytes have enhanced sensitivity to growth inhibition by deoxyadenosine. Flow cytometry was used to investigate the mechanism of deoxyadenosine toxicity in cultured T-leukemic cells. Comparative studies on deoxyadenosine-resistant Epstein-Barr virus-transformed B-lymphocyte cell lines were also performed. After exposure of T-cells to low concentrations of deoxyadenosine (3 .mu.M), in the presence of an adenosine deaminase inhibitor (erythro-9-[3-(2-hydroxynonyl)]adenosine), accumulation of cells with a G1 DNA content was demonstrated. B-cell lines showed a similar degree of growth inhibition after exposure to 200-400 .mu.M deoxyadenosine but were blocked in S phase. The T-cell G1 block was associated with a rise in the deoxyadenosine triphosphate pool, and both these phenomena were prevented by the addition of deoxycytidine. The biochemical mechanism of this G1 block induced by deoxyadenosine in T-cells is not understood.