title: FLT3/ITD expression increases expansion, survival and entry into cell cycle of human haematopoietic stem/progenitor cells.
abstract: Activating mutation of FLT3 by internal tandem duplications (ITDs) in the juxtamembrane region is the most common molecular aberration found in acute myeloid leukaemia (AML). In this study, a lentiviral vector containing two promoters achieved consistent and efficient co-expression of FLT3/ITD and GFP in transduced human CD34(+) haematopoietic stem/progenitor cells (HSPCs). When cultured in medium containing stem cell factor, thrombopoietin and FLT3 ligand (FL), FLT3/ITD-transduced cells demonstrated enhanced self-renewal and survival potential, unaffected by the withdrawal of FL. These cells retained a CD34(+)CD38(-/dim) immunophenotype, typical of HSPCs. Compared to cells transduced with a vector expressing GFP alone, FLT3/ITD-transduced HSPCs had a higher fraction of cells in active cell cycle. FLT3/ITD-transduced HSPCs were more sensitive to the induction of cytotoxicity by CEP-701, a selective FLT3 inhibitor, indicating a rapid 'addiction' to signalling through this oncogenic pathway. The FLT3/ITD-transduced HSPCs showed increased expression of Pim-1, c-Myc and Cyclin D3 (CCND3), each of which may contribute to the altered genetic programme instituted by FLT3/ITD signalling. Taken together, these results indicate that FLT3/ITD mutations may contribute to leukaemic transformation of normal HSPCs by prolonging survival, promoting proliferation and partially blocking differentiation. CEP-701 may act as a potent therapeutic agent for AML stem cells harbouring FLT3/ITD mutations.
authors.affiliation: Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Obdulio
authors.initials: O
authors.lastname: Piloto
authors.forename: Kyu-Tae
authors.initials: KT
authors.lastname: Kim
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Ye
authors.forename: Ho Bao
authors.initials: HB
authors.lastname: Nguyen
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Yu
authors.forename: Mark
authors.initials: M
authors.lastname: Levis
authors.forename: Linzhao
authors.initials: L
authors.lastname: Cheng
authors.forename: Donald
authors.initials: D
authors.lastname: Small
mesh_terms: D018952:Antigens, CD34 / Q000276:immunology; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002227:Carbazoles / Q000627:therapeutic use; D002453:Cell Cycle; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D049109:Cell Proliferation; D002470:Cell Survival; D002471:Cell Transformation, Neoplastic; D056743:Cyclin D3; D016213:Cyclins / Q000235:genetics; D005663:Furans; D015870:Gene Expression; D016259:Genes, myc; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D007211:Indoles / Q000627:therapeutic use; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000378:metabolism*; D051573:Proto-Oncogene Proteins c-pim-1 / Q000235:genetics; D013234:Stem Cells / Q000378:metabolism* / Q000473:pathology; D014161:Transduction, Genetic / Q000379:methods; D014162:Transfection / Q000379:methods; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics / Q000502:physiology*
chemical_list: D018952:Antigens, CD34; D000970:Antineoplastic Agents; C534696:CCND3 protein, human; D002227:Carbazoles; D056743:Cyclin D3; D016213:Cyclins; D005663:Furans; D007211:Indoles; C119379:lestaurtinib; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3; D051573:Proto-Oncogene Proteins c-pim-1