Hyperactive STAT5 hijacks T cell receptor signaling and drives immature T cell acute lymphoblastic leukemia
Tobias Suske, et al.
Tobias Suske, et al.
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Research Article Genetics Hematology

Hyperactive STAT5 hijacks T cell receptor signaling and drives immature T cell acute lymphoblastic leukemia

Abstract

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive immature T cell cancer. Mutations in IL7R have been analyzed genetically, but downstream effector functions such as STAT5A and STAT5B hyperactivation are poorly understood. Here, we studied the most frequent and clinically challenging STAT5BN642H driver in T cell development and immature T cell cancer onset and compared it with STAT5A hyperactive variants in transgenic mice. Enhanced STAT5 activity caused disrupted T cell development and promoted an early T cell progenitor–ALL phenotype, with upregulation of genes involved in T cell receptor (TCR) signaling, even in absence of surface TCR. Importantly, TCR pathway genes were overexpressed in human T-ALL and mature T cell cancers and activation of TCR pathway kinases was STAT5 dependent. We confirmed STAT5 binding to these genes using ChIP-Seq analysis in human T-ALL cells, which were sensitive to pharmacologic inhibition by dual STAT3/5 degraders or ZAP70 tyrosine kinase blockers in vitro and in vivo. We provide genetic and biochemical proof that STAT5A and STAT5B hyperactivation can initiate T-ALL through TCR pathway hijacking and suggest similar mechanisms for other T cell cancers. Thus, STAT5 or TCR component blockade are targeted therapy options, particularly in patients with chemoresistant clones carrying STAT5BN642H.

Authors

Tobias Suske, Helena Sorger, Gabriele Manhart, Frank Ruge, Nicole Prutsch, Mark W. Zimmerman, Thomas Eder, Diaaeldin I. Abdallah, Barbara Maurer, Christina Wagner, Susann Schönefeldt, Katrin Spirk, Alexander Pichler, Tea Pemovska, Carmen Schweicker, Daniel Pölöske, Emina Hubanic, Dennis Jungherz, Tony Andreas Müller, Myint Myat Khine Aung, Anna Orlova, Ha Thi Thanh Pham, Kerstin Zimmel, Thomas Krausgruber, Christoph Bock, Mathias Müller, Maik Dahlhoff, Auke Boersma, Thomas Rülicke, Roman Fleck, Elvin Dominic de Araujo, Patrick Thomas Gunning, Tero Aittokallio, Satu Mustjoki, Takaomi Sanda, Sylvia Hartmann, Florian Grebien, Gregor Hoermann, Torsten Haferlach, Philipp Bernhard Staber, Heidi Anne Neubauer, Alfred Thomas Look, Marco Herling, Richard Moriggl

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Figure 3

STAT5BN642H Rag2–/– T-ALL cells upregulate CD3 surface expression and TCR pathway genes.

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STAT5BN642H Rag2–/– T-ALL cells upregulate CD3 surface expression and TC...
(A) Flow cytometry analysis for CD3 surface expression in DN, DP, or SP8 cells of thymi from STAT5BN642H Rag2–/– (n = 9) or Rag2–/– (n = 5) littermates. (B) Western blot analysis for CD3ζ expression in protein extracts of whole thymi of STAT5BN642H Rag2–/– or Rag2–/– mice and quantification thereof, with n = 6 STAT5BN642H Rag2–/–and n = 4 Rag2–/–. (C) Volcano-plots of RNA-Seq data of DN, DP, and SP8 (STAT5BN642H Rag2–/– and Stat5aS710F Rag2–/–) versus DN (respective Rag2–/– littermates) cells; Padj and logfc determined by DESeq analysis. (D) Western blot analysis for total (t) ZAP70, t-FYN, and t-GRAP2 expression in protein extracts of whole thymi of indicated mouse genotypes. (E) Representative immunohistochemical pY-ZAP70 staining of thymi of STAT5BN642H Rag2–/– (n = 4) or Rag2–/– (n = 3) mice and quantification thereof; 6 distinct areas per slide were subjected to analysis using ImageJ (NIH) and the Colour Deconvolution2 plugin. Original magnification, ×20; scale bar: 200 μm. In A and B, significant differences are indicated as *P < 0.05, ***P < 0.001, ****P < 0.0001 by 1-way ANOVA with Dunnett’s multiple comparison test (A) or unpaired 2-tailed Student’s t test (B). Data are shown as the mean ± SEM.