Therapeutic Targeting of MLL Degradation Pathways in MLL-Rearranged Leukemia

Cell. 2017 Jan 12;168(1-2):59-72.e13. doi: 10.1016/j.cell.2016.12.011. Epub 2017 Jan 5.

Abstract

Chromosomal translocations of the mixed-lineage leukemia (MLL) gene with various partner genes result in aggressive leukemia with dismal outcomes. Despite similar expression at the mRNA level from the wild-type and chimeric MLL alleles, the chimeric protein is more stable. We report that UBE2O functions in regulating the stability of wild-type MLL in response to interleukin-1 signaling. Targeting wild-type MLL degradation impedes MLL leukemia cell proliferation, and it downregulates a specific group of target genes of the MLL chimeras and their oncogenic cofactor, the super elongation complex. Pharmacologically inhibiting this pathway substantially delays progression, and it improves survival of murine leukemia through stabilizing wild-type MLL protein, which displaces the MLL chimera from some of its target genes and, therefore, relieves the cellular oncogenic addiction to MLL chimeras. Stabilization of MLL provides us with a paradigm in the development of therapies for aggressive MLL leukemia and perhaps for other cancers caused by translocations.

Keywords: IRAK1; IRAK4; MLL; MLL chimera; SEC; UBE2O; interleukin-1; mixed-lineage leukemia; super elongation complex; wild-type MLL.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Histone-Lysine N-Methyltransferase / metabolism
  • Humans
  • Interleukin-1 / metabolism
  • Interleukin-1 Receptor-Associated Kinases / antagonists & inhibitors
  • Interleukin-1 Receptor-Associated Kinases / metabolism
  • Leukemia, Biphenotypic, Acute / drug therapy*
  • Leukemia, Biphenotypic, Acute / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Myeloid-Lymphoid Leukemia Protein / metabolism
  • Proteolysis / drug effects*
  • Ubiquitin-Conjugating Enzymes

Substances

  • Interleukin-1
  • Myeloid-Lymphoid Leukemia Protein
  • Histone-Lysine N-Methyltransferase
  • Kmt2a protein, mouse
  • Ubiquitin-Conjugating Enzymes
  • UBE2O protein, human
  • Interleukin-1 Receptor-Associated Kinases