INHIBITORS OF CELL-DIVISION REVERSIBLY MODIFY HEMOGLOBIN CONCENTRATION IN HUMAN ERYTHROLEUKEMIA K562 CELLS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 58  (6) , 1236-1239
Abstract
The human leukemia K562 cell line can be induced by 20 .mu.M hemin to reversibly accumulate embryonic and fetal Hb without any change in the rate of cell division. When the rate of cell division was reduced by glutamine starvation or addition of hydroxyurea, the cells increased by 10-fold the basal Hb level of 0.3-0.5 pg Hb/cell. The combined effects of hemin and inhibitors of cell division permitted K562 cells to attain levels of Hb (26-34 pg Hb/cell) close to that found in normal red cells. This superinduction was reversible and cells could be recycled indefinitely. Furthermore, electrofocusing experiments show that the 3 primary Hb sp. produced by these cells (Hb Gower 1, Hb Portland, and fetal Hb), were induced, or reinduced, synchronously by inhibitors of cell division but asynchronously by hemin. Differing effects of hemin and inhibitors of cell division were observed in the absence of irreversible differentiation and suggest different molecular mechanisms controlling globin gene expression.