title: The HGF/c-Met axis synergizes with G-CSF in the mobilization of hematopoietic stem/progenitor cells.
abstract: As granulocyte-colony-stimulating factor (G-CSF)-induced mobilization of hematopoietic stem/progenitor cells (HSPCs) increases human serum levels of hepatocyte growth factor (HGF), our aim was to investigate the role of HGF and its receptor, c-Met, in the mobilization of HSPC. CD34(+) cells and leukocytes were isolated from the bone marrow (BM) of normal donors and the peripheral blood (PB) of patients mobilized with G-CSF and chemotherapy. Plasma HGF levels were evaluated by ELISA and HGF and c-Met expression by RT-PCR, fluorescence-activated cell sorter (FACS) analysis, and confocal microscopy. Because matrix metalloproteinases (MMPs) facilitate migration across extracellular matrix (ECM) and basement membranes, we also examined expression of MMP-9 and membrane type 1 (MT1)-MMP in hematopoietic cells after HGF stimulation. We found that plasma HGF levels in mobilized (m)PB were higher in patients who are good mobilizers and correlated with their white blood cell (WBC) and CD34(+) cell counts. Moreover, HGF and c-Met expression was significantly higher in mPB CD34(+) cells and leukocytes than in their steady-state BM counterpart cells and was up-regulated by G-CSF. Like G-CSF, HGF increased the secretion of MMP-9 and the expression of MT1-MMP in leukocytes, which was abrogated by the c-Met inhibitor K-252a. This inhibitor also significantly reduced the trans-Matrigel migration of mPB CD34(+) cells toward HGF. Our results suggest that G-CSF-mediated HSPC mobilization occurs in part through the HGF/c-Met axis in HSPC and myeloid cells, eliciting increased production of matrix-degrading enzymes and subsequently facilitating egress of HSPC.
authors.affiliation: Canadian Blood Services R&D, University of Alberta, Edmonton, Canada.
authors.forename: Ali
authors.initials: A
authors.lastname: Jalili
authors.forename: Neeta
authors.initials: N
authors.lastname: Shirvaikar
authors.forename: Leah A
authors.initials: LA
authors.lastname: Marquez-Curtis
authors.forename: A Robert
authors.initials: AR
authors.lastname: Turner
authors.forename: Anna
authors.initials: A
authors.lastname: Janowska-Wieczorek
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism; D002227:Carbazoles / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000069585:Filgrastim; D015870:Gene Expression / Q000235:genetics; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D019650:Hematopoietic Stem Cell Mobilization; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D017228:Hepatocyte Growth Factor / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D026121:Indole Alkaloids / Q000494:pharmacology; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011994:Recombinant Proteins
chemical_list: D018952:Antigens, CD34; D002227:Carbazoles; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D026121:Indole Alkaloids; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D017228:Hepatocyte Growth Factor; C049985:staurosporine aglycone; D019859:Proto-Oncogene Proteins c-met; D020780:Matrix Metalloproteinase 9; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14; D000069585:Filgrastim