Interleukin-4 inhibits the differentiation of mouse myeloid leukemia M1 cells induced by dexamethasone, D-factor/leukemia inhibitory factor and interleukin-6, but not by 1α,25-dihydroxyvitamin D3

AbstractThe effects of interleukin-4(IL-4) on the growth and differentiation of mouse myeloid leukemia M1 cells induced by various differentiation inducers were investigated. IL-4 alone did not have any significant effect on the growth or differentiation of M1 cells, but inhibited their differentiation induced by dexamethasone, D-factor/leukemia inhibitory factor, or interleukin 6. IL-4 also restored the proliferation or M1 cells after growth inhibition during their induction of differentiation by inducers. In contrast, IL-4 enhanced inhibition of growth and induction of differentiation of M1 cells by 1α,25-dihydroxyvitamin D3. These results indicate that modulation or differentiation of M1 cells by IL-4 depends on the differentiation inducer

Synthesis of active metabolite(s) from 1α-hydroxyvitamin D3 by human monocytic leukemia cells

AbstractSynthesis of the biologically active metabolite(s) from 1α-hydroxyvitamin D3 (1α(OH)D3) was examined in various types of human leukemia cell lines. Untreated monocytoid leukemia cells (U937 and HE/S) metabolized 1α(OH)D3 to the active metabolite(s), possibly 1α,24- and/or 1α, 25-dihydroxyvitamin D3, and these cells were efficiently induced to differentiate by treatment with 1α(OH)D3. However, the other types of leukemia cells did not efficiently metabolize it and were not induced to differentiate by 1α(OH)D3. The possible therapeutic advantage of 1α(OH)D3 in the treatment of monocytic leukemia is discussed