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SETBP1 overexpression acts in the place of class-defining mutations to drive FLT3-ITD-mutant AML.

Published version
Peer-reviewed

Change log

Authors

Dovey, Oliver M 
Cooper, Jonathan L 
Friedrich, Mathias J  ORCID logo  https://orcid.org/0000-0003-3184-0283

Abstract

Advances in cancer genomics have revealed genomic classes of acute myeloid leukemia (AML) characterized by class-defining mutations, such as chimeric fusion genes or in genes such as NPM1, MLL, and CEBPA. These class-defining mutations frequently synergize with internal tandem duplications in FLT3 (FLT3-ITDs) to drive leukemogenesis. However, ∼20% of FLT3-ITD-positive AMLs bare no class-defining mutations, and mechanisms of leukemic transformation in these cases are unknown. To identify pathways that drive FLT3-ITD mutant AML in the absence of class-defining mutations, we performed an insertional mutagenesis (IM) screening in Flt3-ITD mice, using Sleeping Beauty transposons. All mice developed acute leukemia (predominantly AML) after a median of 73 days. Analysis of transposon insertions in 38 samples from Flt3-ITD/IM leukemic mice identified recurrent integrations at 22 loci, including Setbp1 (20/38), Ets1 (11/38), Ash1l (8/38), Notch1 (8/38), Erg (7/38), and Runx1 (5/38). Insertions at Setbp1 led exclusively to AML and activated a transcriptional program similar, but not identical, to those of NPM1-mutant and MLL-rearranged AMLs. Guide RNA targeting of Setbp1 was highly detrimental to Flt3ITD/+/Setbp1IM+, but not to Flt3ITD/+/Npm1cA/+, AMLs. Also, analysis of RNA-sequencing data from hundreds of human AMLs revealed that SETBP1 expression is significantly higher in FLT3-ITD AMLs lacking class-defining mutations. These findings propose that SETBP1 overexpression collaborates with FLT3-ITD to drive a subtype of human AML. To identify genetic vulnerabilities of these AMLs, we performed genome-wide CRISPR-Cas9 screening in Flt3ITD/+/Setbp1IM+ AMLs and identified potential therapeutic targets, including Kdm1a, Brd3, Ezh2, and Hmgcr. Our study gives new insights into epigenetic pathways that can drive AMLs lacking class-defining mutations and proposes therapeutic approaches against such cases.

Description

Keywords

Acute Disease, Animals, DNA-Binding Proteins, Histone-Lysine N-Methyltransferase, Leukemia, Myeloid, Acute, Mice, Mutation, Nuclear Proteins, Nucleophosmin

Journal Title

Blood Adv

Conference Name

Journal ISSN

2473-9529
2473-9537

Volume Title

5

Publisher

American Society of Hematology

Rights

Publisher's own licence
Sponsorship
Kay Kendall Leukaemia Fund (KKL1206)
Wellcome Trust (203151/Z/16/Z)
Cancer Research UK (23015)
Wellcome Trust (210926/Z/18/Z)
Medical Research Council (MC_PC_17230)