title: Characterization of spontaneous factor-independent cell lines derived from the human leukemic cell line TF-1: a dominant event.
abstract: Uncontrolled proliferation of acute myeloid leukemia (AML) cells is an important step during leukemogenesis. However, little is known about the mechanisms leading to growth autonomy. Studies using immortalized murine hematopoietic cell lines have suggested that autocrine production of growth factors, or the constitutive activation of molecules in growth factor signalling pathways, are involved. We have established six spontaneous factor-independent cell lines from the human growth factor-dependent TF-1 cell line. The factor-independent cells showed no detectable growth factor activity. Immunoblotting analyses of tyrosine phosphorylation, Raf-1 and extracellular signal-regulated kinase 2 (ERK-2) showed a similar pattern in all the cell lines including TF-1 cells. Furthermore, somatic-cell hybrids between TF-1 and the factor-independent cells grew in absence of growth factor. Taken together this data demonstrates that the factor independence in this system is dominant and suggests that the molecular event is located either downstream of the Raf-1 and MAP kinases pathway or on an alternative pathway. Finally, the karyotype analysis of one factor-independent cell line TF-1i1 and TF-1H- (G418 resistant, HAT sensitive TF-1 cells) and their hybrids demonstrated an unstable derivative chromosome [der(19) t(19;?) (q13.1;?)] which seemed to correlate with the factor-independence capacity. This model may help in our understanding of autonomous proliferation by human myeloid leukemias.
authors.affiliation: DNAX Research Institute of Molecular and Cellular Biology, Palo Alto, CA.
authors.forename: J A
authors.initials: JA
authors.lastname: Gabert
authors.forename: M
authors.initials: M
authors.lastname: Lopez
authors.forename: C D
authors.initials: CD
authors.lastname: Bangs
authors.forename: N
authors.initials: N
authors.lastname: Martina
authors.forename: T A
authors.initials: TA
authors.lastname: Donlon
authors.forename: P
authors.initials: P
authors.lastname: Mannoni
authors.forename: F
authors.initials: F
authors.lastname: Lee
mesh_terms: D000208:Acute Disease; D000818:Animals; D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000096:biosynthesis* / Q000302:isolation & purification; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D017931:DNA Primers; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D007951:Leukemia, Myeloid; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000302:isolation & purification; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000302:isolation & purification; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D019908:Proto-Oncogene Proteins c-raf; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D011518:Proto-Oncogene Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1