1,25-dihydroxyvitamin D3 [1,25(OH)2D] is known to stimulate maturation of the human promyelocytic line HL-60 and murine bone marrow precursor cells along a monocyte/macrophage pathway. In this study, the steroid's effects on the PLB-985 leukemic line were examined. We found that 1,25(OH)2D induces monocytic differentiation of PLB-985 as manifested by morphological appearance, histochemical staining, and changes in cell surface antigen expression. Additionally, there was acquisition of functional monocyte characteristics including phagocytic activity and superoxide anion production via the respiratory burst pathway. Steady state levels of mRNA derived from the leukocyte-specific proto-oncogene c-fgr were also increased by the steroid. Thus, 1,25(OH)2D effectively differentiates PLB-985 cells along a monocytic pathway, providing a useful model of macrophage differentiation.
- Respiratory burst
- S1 nuclease protection analysis