title: Tyrosine kinase inhibitor insensitivity of non-cycling CD34+ human acute myeloid leukaemia cells with FMS-like tyrosine kinase 3 mutations.
abstract: The efficacy of tyrosine kinase (TK) inhibitors on non-cycling acute myeloid leukaemia (AML) cells, previously shown to have potent tumourigenic potential, is unknown. This pilot study describes the first attempt to characterize non-cycling cells from a small series of human FMS-like tyrosine kinase 3 (FLT3) mutation positive samples. CD34+ AML cells from patients with FLT3 mutation positive AML were cultured on murine stroma. In expansion cultures, non-cycling cells were found to retain CD34+ expression in contrast to dividing cells. Leukaemic gene rearrangements could be detected in non-cycling cells, indicating their leukaemic origin. Significantly, the FLT3-internal tandem duplication (ITD) mutation was found in the non-cycling fraction of four out of five cases. Exposure to the FLT3-directed inhibitor TKI258 clearly inhibited the growth of AML CD34+ cells in short-term cultures and colony-forming unit assays. Crucially, non-cycling cells were not eradicated, with the exception of one case, which exhibited exquisite sensitivity to the compound. Moreover, in longer-term cultures, TKI258-treated non-cycling cells showed no growth impairment compared to treatment-naive non-cycling cells. These findings suggest that non-cycling cells in AML may constitute a disease reservoir that is resistant to TK inhibition. Further studies with a larger sample size and other inhibitors are warranted.
authors.affiliation: Section of Haemato-Oncology, The Institute of Cancer Research, Sutton, Surrey Department of Clinical Cytogenetics, The Royal Marsden Hospital, Sutton, Surrey. Caroline.Alvares@icr.ac.uk
authors.forename: Caroline L
authors.initials: CL
authors.lastname: Alvares
authors.forename: Tino
authors.initials: T
authors.lastname: Schenk
authors.forename: Sanna
authors.initials: S
authors.lastname: Hulkki
authors.forename: Toon
authors.initials: T
authors.lastname: Min
authors.forename: Gowri
authors.initials: G
authors.lastname: Vijayaraghavan
authors.forename: Jenny
authors.initials: J
authors.lastname: Yeung
authors.forename: David
authors.initials: D
authors.lastname: Gonzalez
authors.forename: Chi W E
authors.initials: CW
authors.lastname: So
authors.forename: Mel
authors.initials: M
authors.lastname: Greaves
authors.forename: Ian
authors.initials: I
authors.lastname: Titley
authors.forename: Kerol
authors.initials: K
authors.lastname: Bartolovic
authors.forename: Gareth
authors.initials: G
authors.lastname: Morgan
mesh_terms: D000328:Adult; D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001562:Benzimidazoles / Q000494:pharmacology*; D002453:Cell Cycle / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D051379:Mice; D008875:Middle Aged; D009154:Mutation; D010865:Pilot Projects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015363:Quinolones / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay; D055815:Young Adult; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics*
chemical_list: C500007:4-amino-5-fluoro-3-(5-(4-methylpiperazin-1-yl)-1H-benzimidazol-2-yl)quinolin-2(1H)-one; D018952:Antigens, CD34; D000970:Antineoplastic Agents; D001562:Benzimidazoles; D015363:Quinolones; D011505:Protein-Tyrosine Kinases; D051941:fms-Like Tyrosine Kinase 3