CYTOTOXIC EFFECT OF EXTRACELLULAR ATP ON L1210 LEUKEMIC-CELLS AND NORMAL HEMATOPOIETIC STEM-CELLS

The cytotoxic effect of extracellular adenosine triphosphate (ATP) was examined on normal murine hemopoietic stem cells and a representative leukemic cell line (L1210). After L1210 cells were incubated with 4 mM ATP for 3 h, 3H-thymidine incorporation was almost completely inhibited. The number of viable L1210 cells was also significantly decreased and L1210 colony formation was suppressed to approximately 30% of the control level after treatment. The CFU-GM survival rate was reduced to 70%, however, CFU-S and marrow nucleated cell numbers were not changed after the same treatment with ATP. All mice that were injected with the untreated mixture of normal marrow cells (3.3 x 10(4)) and L1210 cells (3.3 x 10(3)) died of leukemia within 18 days. On the contrary, 85% of the recipients given ATP-treated grafts survived mo re th an 70 days. These findings indicate that ATP extra vivo treatment is useful for purging the residual leukemic cells in autologous bone marrow transplantation.