Amplification of a novel c-Kit activating mutation Asb822-Lys in the Kasumi-1 cell line: A t(8;21)-Kit mutant model for acute myeloid leukemia

Alessandro Beghini, Ivana Magnani, Carla B. Ripamonti, Lidia Larizza

Research output: Contribution to journalArticle

Abstract

Introduction: A subset of AML-M2/M4Eo patients has been shown to carry c-kit mutations suggesting that myelomonoblastic leukemia cells, disrupting core binding factor through t(8;21) or inv(16) chromosomal rearrangements, have a common differentiation stage suitable to c-kit mutation. In rare core binding factor leukemia patients an increased dosage of a mutated Asp816Tyr/Val kit allele is achieved through nonrandom duplication of chromosome 4 where the c-kit gene is located. Materials and methods: The c-kit gene was studied in the core binding factor leukemia cell line Kasumi-1 with t(8;21) by fluorescence in situ hybridization and mutation analysis. The dosage of Asn822Lys mutated allele was evaluated by fluorescence semiquantitative PCR. The correct membrane homing of KIT receptor and its activating status was analysed by immunofluorescence and Western blotting respectively. Results: We identified in the Kasumi-1 cell line a novel Asn822Lys ligand-independent c-kit activating mutation and demonstrated by semiquantitative PCR that the mutated allele is about fivefold amplified compared to the normal allele. Fluorescence In Situ Hybridization analysis revealed that c-kit amplification maps to minute 4cen-q11 derived marker chromosome, often carrying duplicated signals, which are unequally distributed in the cell population. The Asn822Lys mutation affects a highly conserved codon within the tyrosine kinase activation loop leading, likewise the Asp816 mutants, to constitutive ligand-independent activation of the KIT receptor. Discussion: Results obtained point to the Kasumi-1 cell line as powerful in-vitro model for further investigation of altered KIT signal transduction pathways in acute myeloid leukemia with core binding factor rearrangements and a useful tool for pharmacological therapeutic targeting.

Original languageEnglish
Pages (from-to)157-163
Number of pages7
JournalHematology Journal
Volume3
Issue number3
DOIs
Publication statusPublished - 2002

Keywords

  • Activating mutation
  • Core binding factor
  • Gene amplification
  • Kasumi-1
  • KIT

ASJC Scopus subject areas

  • Hematology

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