LIPOXYGENASE METABOLISM IS REQUIRED FOR INTERLEUKIN-3 DEPENDENT PROLIFERATION AND CELL-CYCLE PROGRESSION OF THE HUMAN M-07E CELL-LINE

The cell line M-07e requires either Interleukin-3 (IL-3) or granulocyt e-macrophage colony stimulating factor (CM-CSF) for proliferation in v itro. Cells deprived of growth factor for up to 48 hours remain viable but no longer divide. The growth-factor-deprived M-07e cells begin to divide within 48 hours of reexposure to IL-3. Flow cytometric analysi s of M-07e cells labeled with hypotonic propidium iodide demonstrates that the percentage of cells undergoing DNA synthesis decreases from 2 4%, in a log phase population of IL-3 stimulated cells, to 1% when cel ls are deprived of IL-3 for 24 hours. IL-3-deprived cells accumulate p redominantly in a flow cytometry peak representative of G(0)/G(1). DNA synthetic activity, as determined by tritiated thymidine uptake and f low cytometry, resumes between 12 and 18 hours after reexposure to IL- 3, reaching a peak of up to 40% by 24 hours and returning to log phase levels by 72 hours. Prior to initiation of DNA synthesis, increases a re seen in mRNA levels for five-lipoxygenase-activating protein (FLAP) . Following reexposure to IL-3, a rapid lime-dependent biosynthesis of leukotriene D4 (LTD4) is induced by M-07e cells. When IL-3 is added i n the presence of any of three lipoxygenase inhibitors tested (Piripro st, caffeic acid, nordihydroguiaretic acid) or FLAP inhibitor, MK-886, there is dose-dependent inhibition of the resumption of proliferation and of DNA synthesis. Flow cytometric cell cycle analysis demonstrate s that the inhibited cells remain in the G(0)/G(1) population and do n ot progress through the cell cycle. These results are consistent with our previous observation that an intact lipoxygenase pathway is necess ary for hematopoietic growth-factor-stimulated colony formation of nor mal bone marrow myeloid progenitors and suggest that the induction of a lipoxygenase metabolite or metabolites is necessary for myeloid cell s to progress through the cell cycle when stimulated by a hematopoieti c growth factor. (C) 1997 Wiley-Liss, Inc.