[Induction of differentiation of myelomonocytic leukemia cells by mitoxantrone]

We studied the effect of mitoxantrone (MIT) on the proliferation and differentiation of murine myelomonocytic leukemia cell line WEHI-3B (D+), human myelocytic leukemia cell line HL-60 and cells from patients with newly diagnosed acute nonlymphocytic leukemia (ANLL). In a liquid culture, growth inhibition and differentiation of WEHI-3B (D+) cells to mature myeloid cells and a reinforcement tendency of the induction of nitroblue tetrazolium reducing capacity as well as of ASD chroloacetate esterase staining was observed by the treatment with MIT. Fresh ANLL cells classified as M4 were induced by MIT to undergo terminal differentiation to macrophage-like cells. Since at concentrations of WEHI-3B (D+) cells of less than 1 x 10(5)/ml induction of differentiation was observed due to MIT, it is suggested that its mechanism of action differs from that of the induction of differentiation by granulocyte colony-stimulating factor and is due to the direct action of MIT.