REVERSIBILITY OF MONOCYTIC DIFFERENTIATION OF HL-60 CELLS BY 1-ALPHA,25 DIHYDROXYVITAMIN D-3

Although 1 alpha,25(OH)(2)D-3 induces HL-60 cells to differentiate int o monocytes, whether or not these monocytes revert to native promyeloc ytes is not clear. To investigate this question, HL-60 cells were trea ted with 1 alpha 25(OH)(2)D-3, and divided into CD14-positive and -neg ative cells with a cell sorter. These two populations were cultured wi th or without 1 alpha,25(OH)(2)D-3. Sorted CD14-positive HL-60 cells, treated with 1 alpha,25(OH)(2)D-3 for 7 days, reverted to CD14-negativ e cells and promyelocyte-like cells if 1 alpha,25(OH)(2)D-3 was remove d from the medium. We conclude that the 1 alpha,25(OH)(2)D-3-induced d ifferentiation of HL-60 cells into monocytes is reversible, and contin uous administration of 1 alpha,25(OH)(2)D-3 is required for the differ entiation of HL-60 cells. (C) 1997 Elsevier Science Ltd. All rights re served.