Suzuki M, Harashima A, Okochi A, Yamamoto M, Matsuo Y, Motoda R, Yoshioka T, Orita K. Transforming growth factor-beta(1) augments granulocyte-macrophage colony-stimulating factor-induced proliferation of umbilical cord blood CD34(+) cells with an associated tyrosine phosphorylation of STAT5.
Exp Hematol 2002;
30:1132-8. [PMID:
12384143 DOI:
10.1016/s0301-472x(02)00902-5]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE
Several investigators have reported that transforming growth factor (TGF)-beta(1) and granulocyte-macrophage colony-stimulating factor (GM-CSF) synergistically support cell proliferation. However, the mechanisms involved have not been elucidated. To clarify the mechanisms of the synergistic action of TGF-beta(1) and GM-CSF, we compared the activation states of STAT5 and mitogen-activated protein kinase in CD34(+) cells and in GM-CSF-dependent hematopoietic cell lines.
MATERIALS AND METHODS
Human CD34(+) cells and GM-CSF-dependent cell lines (FKH-1, YNH-1, and M-07e) were stimulated with 1.25 ng/mL GM-CSF and/or 0.25 ng/mL TGF-beta(1), and 1.25 ng/mL GM-CSF and/or 0.25 ng/mL, 0.025 ng/mL TGF-beta(1), respectively, and cell proliferation was analyzed by [3H]thymidine uptake. Expression of signal transduction proteins and their phosphorylation states were determined by Western blotting.
RESULTS
TGF-beta(1) synergistically enhanced the GM-CSF-augmented growth of CD34(+) cells and FKH-1 cells, but inhibited the growth of YNH-1 and M-07e cells. Tyrosine phosphorylation of STAT5 induced by GM-CSF was enhanced by stimulation with the combination of TGF-beta(1) and GM-CSF (TGF-beta(1)/GM-CSF) compared with that induced by GM-CSF alone in CD34(+) cells and FKH-1 cells. However, combinations of TGF-beta(1)/GM-CSF caused inhibition of GM-CSF-induced tyrosine phosphorylation in M-07e cells. No significant difference was observed in mitogen-activated protein kinase activation between CD34(+) cells and FKH-1 cells stimulated with GM-CSF/TGF-beta(1) or GM-CSF alone.
CONCLUSIONS
Results suggest that TGF-beta(1) may augment GM-CSF-induced proliferation of CD34(+) cells in association with enhanced tyrosine phosphorylation of STAT5. Our data suggest a novel mechanism for the synergistic enhancement of cellular growth induced by the combination of TGF-beta(1) and GM-CSF.
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