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GATA2 haploinsufficiency accelerates EVI1-driven leukemogenesis

Saori Katayama, Mikiko Suzuki, Ayaka Yamaoka, Nadine Keleku-Lukwete, Fumiki Katsuoka, Akihito Otsuki, Shigeo Kure, James Douglas Engel and Masayuki Yamamoto

Key points

  • Leukemic cells in an inv(3)(q21q26) EVI1 misexpression mouse model are able to differentiate toward myeloid lineage

  • Gata2 heterozygous deletion accelerates EVI1 misexpression leukemia by inducing proliferation and differentiation defect of leukemia cells

Abstract

Chromosomal rearrangements between 3q21 and 3q26 induce inappropriate EVI1 expression by recruiting a GATA2-distal hematopoietic enhancer (G2DHE) to the proximity of the EVI1 gene, leading to myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). The acquisition of G2DHE by the EVI1 gene reciprocally deprives this enhancer of one of the two GATA2 alleles, resulting in a loss of function genetic reduction in GATA2 abundance. As GATA2 haploinsufficiency is strongly associated with MDS and AML, here we asked whether EVI1 misexpression and GATA2 haploinsufficiency both contributed to the observed leukemogenesis by using a 3q21q26 mouse model that recapitulates the G2DHE-driven EVI1 misexpression but in this case coupled to a Gata2 heterozygous germ-line deletion. Of note, the Gata2 heterozygous deletion promoted the EVI1-provoked leukemic transformation, resulting in an early onset of leukemia. The 3q21q26 mice suffer from leukemia in which B220+ cells and/or Gr1+ leukemic cells occupied their bone marrows. We found that B220+Gr1-c-Kit+ population contains leukemia-initiating cells and supplies Gr1+ leukemia cells in the 3q21q26 leukemia. When Gata2 expression levels in the B220+Gr1-c-Kit+ cells were decreased due to Gata2 heterozygous deletion or spontaneous phenomenon, myeloid differentiation of the B220+Gr1-c-Kit+ cells was suppressed and the cells acquired induced proliferation as well as B-lymphoid-primed characteristics. Competitive transplantation analysis revealed that Gata2 heterozygous deletion confers selective advantage to EVI1-expressing leukemia cell expansion in recipient mice. These results demonstrate that both the inappropriate stimulation of EVI1 and the loss of one allele equivalent of Gata2 expression contribute to the acceleration of leukemogenesis.

  • Submitted December 12, 2016.
  • Accepted June 8, 2017.