title: Expression of stem cell factor and c-kit mRNA in cultured endothelial cells, monocytes and cloned human bone marrow stromal cells (CFU-RF).
abstract: Previously, we have shown that conditioned medium from a subpopulation of human marrow stromal cells (CFU-RF) contain an activity able to stimulate the growth of macroscopic epo-dependent erythroid colonies. The ligand for the product of the c-kit proto-oncogene (also known as stem cell factor or SCF), among other activities, has been reported to have similar effects on erythroid colony growth. We have also presented data showing that SCF together with phytohemagglutinin-stimulated leukocyte conditioned medium can stimulate erythroid colony growth in the presence of antibodies to erythropoietin. Using the human SCF cDNA probe (K. Zsebo, Amgen Inc.) we now show that cells derived from CFU-RF colonies express SCF but not c-kit. Human umbilical vein endothelial cells were also found to express SCF and this expression was increased by addition of monocyte supernatant, IL-1 beta or thrombin. Cells of the human erythroleukemia cell line HEL were found to express c-kit but not SCF. Neither c-kit nor SCF mRNA were detected in phytohemagglutinin-stimulated lymphocytes. Together, these data support the view that the behaviour of proliferating erythroid stem cells in the marrow, which may express c-kit, could be regulated by membrane-bound SCF present on surrounding stromal cells.
authors.affiliation: Ottawa Centre, Canadian Red Cross Blood Transfusion Service, Ontario.
authors.forename: M T
authors.initials: MT
authors.lastname: Aye
authors.forename: S
authors.initials: S
authors.lastname: Hashemi
authors.forename: B
authors.initials: B
authors.lastname: Leclair
authors.forename: A
authors.initials: A
authors.lastname: Zeibdawi
authors.forename: E
authors.initials: E
authors.lastname: Trudel
authors.forename: M
authors.initials: M
authors.lastname: Halpenny
authors.forename: V
authors.initials: V
authors.lastname: Fuller
authors.forename: G
authors.initials: G
authors.lastname: Cheng
mesh_terms: D001483:Base Sequence; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000502:physiology*; D015870:Gene Expression; D016298:Hematopoietic Cell Growth Factors / Q000235:genetics*; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology; D008213:Lymphocyte Activation; D008264:Macrophages / Q000502:physiology; D008969:Molecular Sequence Data; D009000:Monocytes / Q000502:physiology*; D009841:Oligonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit; D012333:RNA, Messenger / Q000235:genetics; D019089:Stem Cell Factor; D013917:Thrombin / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D016298:Hematopoietic Cell Growth Factors; D007375:Interleukin-1; C000715470:MAS1 protein, human; D009841:Oligonucleotides; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D019089:Stem Cell Factor; D014409:Tumor Necrosis Factor-alpha; D019009:Proto-Oncogene Proteins c-kit; D013917:Thrombin