Incorporation of nucleic acid and protein precursors in enriched populations of proliferating normal and leukemic cells

Nucleic acid and protein synthesis was determined in immature myeloid cells isolated from seven normal bone marrow samples and compared to blasts from nine patients with full-blown acute non-lymphocytic leukemia. Samples obtained from normal bone marrow contained a mean of 82% immature myeloid cells with 29.9% S-phase cells. These cells incorporated [ 3H]thymidine with a mean of 17,500 counts/min [ 3H]uridine with a mean of 24,000 counts/min and [ 3H]leucine with a mean of 2100 counts/min per 0.2 × 10 6 cells. Leukemic bone marrow cells could be separated in fractions with different proliferative activities. Leukemic samples with a mean of 3.6% S-phase cells incorporated [ 3H]thymidine with a mean of 1100 counts/min, [ 3H]uridine with a mean of 15,700 counts/min and [ 3H]leucine with a mean of 2600 counts/min per 0.2 × 10 6 cells. For leukemic samples with a mean of 30.6% S-phase cells these values were: [ 3H]thymidine 22,200 counts/min, [ 3H]uridine 49,700 counts/min and [ 3H]leucine 6700 counts/min per 0.2 × 10 6 cells. The incorporation studies were carried out for the first time in normal and leukemic cells with a comparable proliferative activity. Non-lymphocytic leukemic blastic cells showed a two-fold increase in RNA synthesis and a three-fold increase in protein synthesis compared to enriched samples of normal early myeloid cells with the same proliferative activity.