ABSTRACT

In this chapter, the authors observe the production of low quantities of a GM-CSF-like activity in factor-independent derivative cells capable of stimulating FDC-P1 proliferation, but others have also observed such activity in cells that are still factor-dependent. They have subsequently performed independent studies of growth factor dependent cell lines and other studies of marrow adherent stromal cell lines, examining these various mechanistic possibilities that might explain our phenomenologie results of coincubation, if they should occur in situ. The authors generated a naive IL-3 dependent cell line from the NFS/N mouse called NFS/N1 ,H7. They studied biochemically the stimulated formation of intracellular cAMP in control vs. butyrate treated FDC-P1 cells and growth factor-independent cells derived from FDC-P1, and found significant augentation of cAMP formation by butyrate. In summary, two different IL-3-dependent cell lines were so altered by oncogenic ras to favor leukemic growth in a paracrine setting.