The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

Cell Death Dis. 2021 Jul 5;12(7):675. doi: 10.1038/s41419-021-03948-6.

Abstract

Mutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CCAAT-Enhancer-Binding Proteins / genetics
  • CCAAT-Enhancer-Binding Proteins / metabolism*
  • Cell Differentiation*
  • Cells, Cultured
  • Female
  • Gene Expression Regulation, Leukemic
  • Granulocyte Precursor Cells / metabolism*
  • Granulocyte Precursor Cells / transplantation
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Leukemia, Monocytic, Acute / genetics
  • Leukemia, Monocytic, Acute / metabolism*
  • Mice, Inbred C57BL
  • Mutation*
  • Neutrophils / metabolism*
  • Neutrophils / transplantation
  • Up-Regulation

Substances

  • CCAAT-Enhancer-Binding Proteins
  • CEBPA protein, human
  • CEBPA protein, mouse
  • Homeodomain Proteins