title: Tumor necrosis factor alpha (TNF alpha) downregulates c-kit proto-oncogene product expression in normal and acute myeloid leukemia CD34+ cells via p55 TNF alpha receptors.
abstract: Tumor necrosis factor alpha (TNF alpha), as a modulator of hematopoiesis, interacts with many growth factor receptors, such as interleukin-3, granulocyte-macrophage colony-stimulating factor (CSF), and granulocyte-CSF receptors. Here, we studied the interactions between TNF alpha and the stem cell factor (SCF) receptor, c-kit, in normal CD34+ hematopoietic progenitors and their leukemic counterpart, ie, acute myeloid leukemic (AML) CD34+ cells coexpressing c-kit antigen. The results showed that (1) incubation of normal bone marrow mononuclear cells with 200 U/mL rhTNF alpha for 20 hours induced a diminution of 31.2% +/- 5.2% of CD34+ cells coexpressing c-kit; (2) the same decrease was observed using purified CD34+ cells and, furthermore, their proliferative response to SCF was inhibited by 31.5% +/- 7.3% after exposure to TNF alpha; (3) similar experiments performed on CD34+ c-kit+ AML cells from 11 patients gave comparable results. Further analysis at the mRNA level indicated that TNF alpha decreased c-kit mRNA transcripts. Moreover, using monoclonal antibodies against the two types of TNF alpha receptors, p75 and p55, we showed that the downregulation of c-kit proto-oncogene product by TNF alpha, on normal and leukemic CD34+ cells, was exclusively mediated by the TNF alpha p55 receptor. Therefore, we conclude that TNF alpha acts as a downregulator of the SCF receptor expression.
authors.affiliation: Department of Hematology, Faculté de Médecine Saint Antoine, Paris, France.
authors.forename: E
authors.initials: E
authors.lastname: Khoury
authors.forename: C
authors.initials: C
authors.lastname: Andre
authors.forename: S
authors.initials: S
authors.lastname: Pontvert-Delucq
authors.forename: B
authors.initials: B
authors.lastname: Drenou
authors.forename: C
authors.initials: C
authors.lastname: Baillou
authors.forename: M
authors.initials: M
authors.lastname: Guigon
authors.forename: A
authors.initials: A
authors.lastname: Najman
authors.forename: F M
authors.initials: FM
authors.lastname: Lemoine
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34; D001483:Base Sequence; D001854:Bone Marrow Cells; D002455:Cell Division; D015972:Gene Expression Regulation, Neoplastic; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D008969:Molecular Sequence Data; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D016184:Receptors, Colony-Stimulating Factor / Q000235:genetics*; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology*; D019089:Stem Cell Factor; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D016298:Hematopoietic Cell Growth Factors; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D016184:Receptors, Colony-Stimulating Factor; D018124:Receptors, Tumor Necrosis Factor; D019089:Stem Cell Factor; D014409:Tumor Necrosis Factor-alpha; D019009:Proto-Oncogene Proteins c-kit; D020794:Receptor Protein-Tyrosine Kinases