Synergistic effects of hepatocyte growth factor on human cord blood CD34+ progenitor cells are the result of c-met receptor expression.
Hepatocyte growth factor (HGF) is a pleiotropic growth factor which, in addition to its mitogenic potency for primary hepatocytes, also has a role in the regulation of cell motility, cell growth and morphogenesis. In the present study, we show that c-met, the high-affinity receptor for HGF, is expressed on human cord blood (CB) CD34+ progenitor cells and CD34+Thy-1+ Lin-(lin-) cells. We have investigated the capacity of HGF to synergize with other growth factors to induce colony formation by CB CD34+ progenitor cells. CD34+ cells were cultured in semisolid medium containing serum with increasing concentrations of GM-CSF, G-CSF, macrophage colony-stimulating factor (M-CSF), stem cell factor (SCF), interleukin 3 (IL-3) and IL-11 alone or in combination with HGF. HGF acted as a potent synergist and enhanced, up to fourfold, colony formation induced by GM-CSF, G-CSF or M-CSF. HGF in combination with SCF, IL-3 or IL-11 did not induce proliferation of colony forming units-granulocyte macrophage (CFU-GM) above control levels. In serum-deprived cultures, HGF was only detectably synergistic with IL-11, and all other culture combinations showed no proliferation. To determine whether the stimulatory effect of IL-11 and the synergistic effect of HGF in the absence of serum could be attributed to the effect of these two cytokines on stem cells, IL-11-stimulated and unstimulated lin- cells were analyzed for expression of c-met. CD34+Thy-1+Lin- cells were positive for c-met, both in the presence and absence of IL-11 stimulation, and Northern analysis indicated that c-met RNA expression was upregulated in response to IL-11 compared to unstimulated controls. These results provide strong evidence for upregulation of the HGF receptor on primitive hematopoietic cells by IL-11, and for the synergistic role of HGF in colony formation by hematopoietic stem cells.
Department of Radiation Oncology, University of Pittsburgh, PA 15213, USA.
J P
JP
Goff
D S
DS
Shields
B E
BE
Petersen
V F
VF
Zajac
G K
GK
Michalopoulos
J S
JS
Greenberger
D018952:Antigens, CD34 / Q000032:analysis; D001798:Blood Proteins / Q000494:pharmacology; D015152:Blotting, Northern; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006410:Hematopoiesis / Q000187:drug effects; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D006801:Humans; D007150:Immunohistochemistry; D017370:Interleukin-11 / Q000494:pharmacology; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D019859:Proto-Oncogene Proteins c-met; D012333:RNA, Messenger / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D013234:Stem Cells / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D018800:Thy-1 Antigens / Q000032:analysis; D015854:Up-Regulation / Q000187:drug effects
D018952:Antigens, CD34; D001798:Blood Proteins; D016895:Culture Media, Serum-Free; D017370:Interleukin-11; D012333:RNA, Messenger; D018800:Thy-1 Antigens; D016179:Granulocyte Colony-Stimulating Factor; D017228:Hepatocyte Growth Factor; D016173:Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases