International Journal of Cell Cloning, Vol 2, 368-382, Copyright © 1984 by AlphaMed Press
Enhancement of colony-stimulating activity (CSA) on murine CFU-gm by the H-4-II-E2 (H4) tumor cell line of the rat
CJ Kovacs, RM Pogrow, MJ Evans, RM Johnke and DA Emma
The effect of the H-4-II-E2 (H4) rat tumor cell line on murine
granulocyte/macrophage colony-forming units (CFU-gm) was studied in vitro
using a bilayer (agar/methylcellulose) culture system over the tumor cell
feeder and 10% colony-stimulating activity (CSA). The H4 cells demonstrated
an amplification of CSA from several sources and of CFU-gm growth of murine
marrow, including the CSA present in L-cell- conditioned medium (L-CSA;
200% of control). The amplification did not result from CSA produced by the
H4 cell line, nor was cell-to-cell contact necessary for enhanced CFU-gm
growth. Amplification of L-CSA was not mediated by endogenous or exogenous
prostaglandin E concentrations in the in vitro system. Furthermore,
incubation of the non-adherent marrow cell population with H4 tumor cells
for 24 h prior to assaying for CFU-gm resulted in more colonies,
independent of the continued presence of H4 tumor cells. The data suggest
that the H4 tumor cells produce a readily diffusable, soluble factor that
may amplify the effect of L-CSA on CFU-gm by stimulating a more primitive
progenitor cell that expands the CFU-gm population.
