International Journal of Cell Cloning, Vol 4, 126-134, Copyright © 1986 by AlphaMed Press
Pre-CFU-f: young-type stromal stem cells in murine bone marrow following administration of DNA inhibitors
Z Ben-Ishay, G Prindull, S Sharon and A Borenstein
Occurrence of young-type stromal stem cells (defined here as "pre-CFU- f")
in murine bone marrow is reported in this study. Two consecutive
intraperitoneal (i.p.) cytosine arabinoside (ara-C) injections were
administered to C57B1 mice (2 X 200 mg/kg at 6-h intervals). Two days later
the bone marrow was collected and assayed for colony-forming
units-fibroblastoid (defined here as "CFU-f"). In additional experiments,
ara-C-treated marrow was exposed in vitro to hydroxyurea (HU; "hydroxyurea
killing test"), prior to plating, to establish the cycling state of stromal
stem cells. In separate cultures of ara-C- treated marrow, replating of
adherent cells was carried out up to quaternary sub-cultures. The results
indicate ara-C-treated marrow produces approximately 20% "huge"
fibroblastoid colonies (approximately 5 mm diameter versus 0.5-2 mm normal
size); most stromal stem cells producing huge colonies are cycling cells;
and adherent cells from primary ara-C-treated marrow cultures replated to
secondary cultures produce adherent layers with double the number of cells
than in the control secondary cultures. We conclude that the ara-C-treated
murine bone marrow contains certain young-type cycling stromal stem cells
which we refer to as pre-CFU-f. These stem cells produce huge fibroblastoid
colonies in culture, indicating that they probably go through more cell
cycles than CFU-f during the culture period. Alternatively, pre-CFU-f may
have a higher self-replicative capacity than CFU-f.
