Basic fibroblast growth factor antagonizes transforming growth factor
beta-mediated erythroid differentiation in K562 cells
PE Burger, EB Dowdle, PT Lukey and EL Wilson
Department of Clinical Science and Immunology, University of Cape Town
Medical School, South Africa.
Basic fibroblast growth factor (bFGF) and transforming growth factor- beta
1 (TGF-beta) have both been shown to act on hematopoietic progenitor cells.
bFGF is a hematopoietic cytokine that acts on progenitor cells in concert
with other cytokines to promote their proliferation. TGF-beta induces
erythroid differentiation in K562 cells. To determine whether bFGF might
act on progenitor cells by antagonizing the effects of cytokines that
induce differentiation, we determined the effects of bFGF on the
TGF-beta-mediated induction of hemoglobin synthesis in K562 cells. bFGF
antagonized the TGF-beta- mediated induction of hemoglobin in a
dose-dependent manner, with 0.1 ng/mL bFGF inhibiting hemoglobin induction
by 40% and 10 ng/mL bFGF completely abrogating hemoglobin production. bFGF
was most effective at antagonizing the TGF-beta-mediated induction of
hemoglobin if it and TGF-beta were added simultaneously to K562 cells, but
delayed addition of bFGF to TGF-beta-treated cultures still resulted in
significant inhibition of hemoglobin synthesis. The inhibitory effects of
bFGF on hemoglobin production were fully reversible, showing that bFGF did
not permanently alter the phenotype of K562 cells. The hemin-mediated
induction of hemoglobin synthesis in K562 cells was only partially negated
by bFGF. bFGF also diminished the expression of glycophorin A on the
surface of K562 cells. These results indicate that bFGF might increase
progenitor/stem cell numbers by antagonizing the effects of cytokines that
induce differentiation, thereby increasing the pool of proliferating
progenitor/stem cells.
Volume 83,
Issue 7,
pp. 1808-1812,
04/01/1994
Copyright © 1994 by The American Society of Hematology
