title: Expression and activity of Fyn mediate proliferation and blastic features of chronic myelogenous leukemia.
abstract: The BCR-ABL1 oncogene is a tyrosine kinase that activates many signaling pathways, resulting in the induction of chronic myeloid leukemia (CML). Kinase inhibitors, such as imatinib, have been developed for the treatment of CML; however, the terminal, blast crisis phase of the disease remains a clinical challenge. Blast crisis CML is difficult to treat due to resistance to tyrosine kinase inhibitors, increased genomic instability and acquired secondary mutations. Our recent studies uncovered a role for Fyn in promoting BCR-ABL1 mediated cell growth and sensitivity to imatinib. Here we demonstrate that Fyn contributes to BCR-ABL1 induced genomic instability, a feature of blast crisis CML. Bone marrow cells and mouse embryonic fibroblasts derived from Fyn knockout mice transduced with BCR-ABL1 display slowed growth and clonogenic potential as compared to Fyn wild-type BCR-ABL1 expressing counterparts. K562 cells overexpressing constitutively active Fyn kinase were larger in size and displayed an accumulation of genomic abnormalities such as chromosomal aberrations and polyploidy. Importantly, loss of Fyn protected mouse embryonic fibroblast cells from increased number of chromosomal aberrations and fragments induced by BCR-ABL1. Together, these results reveal a novel role for Fyn in regulating events required for genomic maintenance and suggest that Fyn kinase activity plays a role in the progression of CML to blast crisis.
authors.affiliation: Department of Pediatrics Research, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Singh
authors.forename: Adrienne
authors.initials: A
authors.lastname: Howard
authors.forename: Mary E
authors.initials: ME
authors.lastname: Irwin
authors.forename: Yin
authors.initials: Y
authors.lastname: Gao
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Lu
authors.forename: Asha
authors.initials: A
authors.lastname: Multani
authors.forename: Joya
authors.initials: J
authors.lastname: Chandra
mesh_terms: D000818:Animals; D017209:Apoptosis; D001752:Blast Crisis / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D015153:Blotting, Western; D002453:Cell Cycle; D002454:Cell Differentiation; D049109:Cell Proliferation; D048429:Cell Size; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000378:metabolism*; D042822:Genomic Instability; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D018345:Mice, Knockout; D051076:Proto-Oncogene Proteins c-fyn / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*
chemical_list: C494957:FYN protein, human; D016044:Fusion Proteins, bcr-abl; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn