Over-expression of c-src or v-src in bone marrow stromal cells stimulates
hematopoiesis in long-term bone marrow culture
J Mladenovic and SM Anderson
Department of Medicine, SUNY, Stony Brook 11794.
The S17 murine stromal cell line was infected with retroviral vectors
encoding the v-src and c-src oncogenes and cells expressing high levels of
either pp60v-src or pp60c-src were isolated. Long-term bone marrow cultures
(LTBMCs) established with these different stromal cell lines showed that
progenitor cells proliferated to a greater extent in cultures with stromal
cells that over-expressed either c-src or v-src. An increase in the number
of granulocytes, monocytes, and colony- forming units
granulocyte-macrophage (CFU-GM) in the nonadherent cell population of
LTBMCs prepared with S17/v-src or S17/c-src stromal cells was observed.
Conditioned media from the S17/v-src and S17/src stromal cell lines
stimulated the formation of CFU-GM in the absence of additional
hematopoietic cell growth factors. Conditioned media from S17/v-src and
S17/c-src stimulated proliferation of the granulocyte- macrophage
colony-stimulating factor (GM-CSF)-responsive cell line FDCP- 1 and this
stimulation was inhibited by neutralizing antisera to murine GM-CSF. An
increase in the concentration of GM-CSF was confirmed by enzyme-linked
immunosorbent assay. No secretion of interleukin-1 alpha (IL-1 alpha) or
tumor necrosis factor-alpha was detected by any of the stromal cell lines.
There was no increase in the secretion of either CSF-1 or IL-6 by either
S17/v-src or S17/c-src. The addition of 1 micrograms/mL monoclonal
anti-GM-CSF antibody to LTBMCs caused a decrease in the number of
nonadherent cells in cultures established with each of the different
stromal cell lines. Northern blot analysis showed no difference in the
level of GM-CSF RNA among the different stromal cell lines. These studies
suggest that the increased proliferation of hematopoietic progenitor cells
in LTBMCs with S17/v- src or S17/c-src cells may result from a
posttranscriptional event that elevates production of GM-CSF by the
S17/c-src and S17/v-src stromal cells.
Volume 80,
Issue 12,
pp. 3079-3089,
12/15/1992
Copyright © 1992 by The American Society of Hematology
