Transforming growth factor-beta 1 induces apoptosis independently of p53 and selectively reduces expression of Bcl-2 in multipotent hematopoietic cells.
Francis, Julia M Heyworth, Clare M Spooncer, Elaine Pierce, Andrew Dexter, T Michael Whetton, Anthony D
Francis, Julia M
Heyworth, Clare M
Spooncer, Elaine
Pierce, Andrew
Dexter, T Michael
Whetton, Anthony D
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Abstract
Transforming growth factor-beta1 (TGF-beta1) can inhibit cell proliferation or induce apoptosis in multipotent hematopoietic cells. To study the mechanisms of TGF-beta1 action on primitive hematopoietic cells, we used the interleukin-3 (IL-3)-dependent, multipotent FDCP-Mix cell line. TGF-beta1-mediated growth inhibition was observed in high concentrations of IL-3, while at lower IL-3 concentrations TGF-beta1 induced apoptosis. The proapoptotic effects of TGF-beta1 occur via a p53-independent pathway, since p53(null) FDCP-Mix demonstrated the same responses to TGF-beta1. IL-3 has been suggested to enhance survival via an increase in (antiapoptotic) Bcl-x(L) expression. In FDCP-Mix cells, neither IL-3 nor TGF-beta1 induced any change in Bcl-x(L) protein levels or the proapoptotic proteins Bad or Bax. However, TGF-beta1 had a major effect on Bcl-2 levels, reducing them in the presence of high and low concentrations of IL-3. Overexpression of Bcl-2 in FDCP-Mix cells rescued them from TGF-beta1-induced apoptosis but was incapable of inhibiting TGF-beta1-mediated growth arrest. We conclude that TGF-beta1-induced cell death is independent of p53 and inhibited by Bcl-2, with no effect on Bcl-x(L). The significance of these results for stem cell survival in bone marrow are discussed.
Description
Date
2000-12-15
Publisher
Collections
Keywords
Haematopoietic Stem Cells
Tumour Suppressor Protein p53
Tumour Suppressor Protein p53
Type
Article
Citation
Transforming growth factor-beta 1 induces apoptosis independently of p53 and selectively reduces expression of Bcl-2 in multipotent hematopoietic cells. 2000, 275 (50):39137-45 J. Biol. Chem.