Establishment of the acute myeloid leukemia cell line Kasumi-6 from a patient with a dominant-negative mutation in the DNA-binding region of the C/EBPα gene

Hiroya Asou, Adrian F. Gombart, Seisho Takeuchi, Hideo Tanaka, Maki Tanioka, Hirotaka Matsui, Akiro Kimura, Toshiya Inaba, H. Phillip Koeffler

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

A myeloid leukemia cell line designated Kasumi-6 was established from the bone marrow cells of an individual with acute myeloid leukemia, subtype M2. Both the original leukemic cells and the Kasumi-6 cell line harbor a hemizygous point mutation in the gene encoding the CCAAT/enhancer binding protein alpha (C/EBPα), a critical myeloid transcriptional factor. The C to G transition at nucleotide 1063 of the C/EBPα gene results in amino acid transition R305P in the fork or hinge region between the DNA-binding basic region and the leucine zipper dimerization domain of the C/EBPα protein. The Kasumi-6 cells expressed both the p42 and p30 isoforms of the C/EBPα protein endogenously, but electrophoretic mobility shift assays demonstrated an absence of C/EBPα binding to its respective site. Exogenous expression of the mutant form of C/EBPα demonstrated that it was unable to bind DNA and activate transcription from a G-CSF receptor - luciferase reporter construct. Furthermore, coexpression of the wild-type and mutant forms revealed that the mutant form repressed reporter gene activation by the wild type in a dose-responsive manner. This was concomitant with a dose-responsive decrease in wild-type protein binding to the G-CSF receptor C/EBP site. The data suggest that the R305P alteration confers a dominant-negative property on the mutant C/EBPα protein whereby the mutant polypeptide heterodimerizes with the wild-type polypeptide and prevents it from binding to DNA, thus blocking transcriptional activation. The Kasumi-6 cell line can serve as a model to study the cellular and molecular biology of the non-t(8;21) M2 type of myeloid leukemia and can elucidate the role of mutated C/EBPα in leukemogenesis.

Original languageEnglish
Pages (from-to)167-174
Number of pages8
JournalGenes Chromosomes and Cancer
Volume36
Issue number2
DOIs
Publication statusPublished - Feb 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • Genetics
  • Cancer Research

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