Amiloride potentiation of differentiation of human promyelocytic cell line HL-60.

Cells of the human acute promyelocytic cell line HL-60 undergo differentiation when exposed to dimethyl sulfoxide (DMSO); in this report, amiloride, an inhibitor of passive intracellular Na+ flux, potentiated the DMSO-induced differentiation of HL-60 cells. This effect was seen at several concentrations of DMSO. Amiloride alone did not affect HL-60 differentiation. Various analogues of amiloride were tested for their ability to potentiate differentiation of HL-60 cells. The synergistic induction of myeloid differentiation by a membrane solvent (DMSO) and an Na+ transport inhibitor (amiloride) suggested membrane cation flux as being important in initiating differentiation.