title: Expression of bcr-abl abrogates factor-dependent growth of human hematopoietic M07E cells by an autocrine mechanism.
abstract: The introduction of a retrovirus vector expressing p210bcr-abl (P210) into the human factor-dependent cell line M07E resulted in the rapid outgrowth of factor-independent cells. Early after infection, four factor-independent clones were isolated and analyzed in greater detail along with mass populations obtained from separate infections. High levels of P210 tyrosine kinase activity were measured in the factor-independent cells. The mass populations and three of the four clones remained responsive to exogenous growth factors. Concentrated conditioned media isolated from the factor-independent populations and from all clones contained biologically active granulocyte-macrophage colony-stimulating factor (GM-CSF); interleukin-3 (IL-3) was detected at low levels in the mass population and in two of the clones. Neutralizing antibodies to IL-3, GM-CSF, and mast cell growth factor inhibited proliferation of the factor responsive clones by 60% to 90%. These results indicate that the growth autonomy of the P210-expressing M07E cells was acquired via an autocrine mechanism. In addition to factor-independent growth, P210-expressing M07E cells readily acquired a more mature megakaryocytic phenotype compared with control M07E cells. These data provide experimental evidence that expression of P210 tyrosine kinase in human hematopoietic cells induced growth factor secretion resulting in a pleiotropic effect on growth factor dependence and differentiation.
authors.affiliation: Department of Genetics, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Sirard
authors.forename: P
authors.initials: P
authors.lastname: Laneuville
authors.forename: J E
authors.initials: JE
authors.lastname: Dick
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D016044:Fusion Proteins, bcr-abl / Q000032:analysis*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis / Q000494:pharmacology*; D006801:Humans; D007377:Interleukin-3 / Q000032:analysis / Q000494:pharmacology*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000473:pathology
chemical_list: D007377:Interleukin-3; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D016044:Fusion Proteins, bcr-abl