Pharmacological inhibition of the transcription factor PU.1 in leukemia
Iléana Antony-Debré, Ananya Paul, Joana Leite, Kelly Mitchell, Hye Mi Kim, Luis A. Carvajal, Tihomira I. Todorova, Kenneth Huang, Arvind Kumar, Abdelbasset A. Farahat, Boris Bartholdy, Swathi-Rao Narayanagari, Jiahao Chen, Alberto Ambesi-Impiombato, Adolfo A. Ferrando, Ioannis Mantzaris, Evripidis Gavathiotis, Amit Verma, Britta Will, David W. Boykin, W. David Wilson, Gregory M.K. Poon, Ulrich Steidl
Iléana Antony-Debré, Ananya Paul, Joana Leite, Kelly Mitchell, Hye Mi Kim, Luis A. Carvajal, Tihomira I. Todorova, Kenneth Huang, Arvind Kumar, Abdelbasset A. Farahat, Boris Bartholdy, Swathi-Rao Narayanagari, Jiahao Chen, Alberto Ambesi-Impiombato, Adolfo A. Ferrando, Ioannis Mantzaris, Evripidis Gavathiotis, Amit Verma, Britta Will, David W. Boykin, W. David Wilson, Gregory M.K. Poon, Ulrich Steidl
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Research Article Hematology

Pharmacological inhibition of the transcription factor PU.1 in leukemia

Abstract

The transcription factor PU.1 is often impaired in patients with acute myeloid leukemia (AML). Here, we used AML cells that already had low PU.1 levels and further inhibited PU.1 using either RNA interference or, to our knowledge, first-in-class small-molecule inhibitors of PU.1 that we developed specifically to allosterically interfere with PU.1-chromatin binding through interaction with the DNA minor groove that flanks PU.1-binding motifs. These small molecules of the heterocyclic diamidine family disrupted the interaction of PU.1 with target gene promoters and led to downregulation of canonical PU.1 transcriptional targets. shRNA or small-molecule inhibition of PU.1 in AML cells from either PU.1lo mutant mice or human patients with AML-inhibited cell growth and clonogenicity and induced apoptosis. In murine and human AML (xeno)transplantation models, treatment with our PU.1 inhibitors decreased tumor burden and resulted in increased survival. Thus, our study provides proof of concept that PU.1 inhibition has potential as a therapeutic strategy for the treatment of AML and for the development of small-molecule inhibitors of PU.1.

Authors

Iléana Antony-Debré, Ananya Paul, Joana Leite, Kelly Mitchell, Hye Mi Kim, Luis A. Carvajal, Tihomira I. Todorova, Kenneth Huang, Arvind Kumar, Abdelbasset A. Farahat, Boris Bartholdy, Swathi-Rao Narayanagari, Jiahao Chen, Alberto Ambesi-Impiombato, Adolfo A. Ferrando, Ioannis Mantzaris, Evripidis Gavathiotis, Amit Verma, Britta Will, David W. Boykin, W. David Wilson, Gregory M.K. Poon, Ulrich Steidl

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Figure 6

PU.1 inhibitors decrease granulomonocytic differentiation in a reversible manner.

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PU.1 inhibitors decrease granulomonocytic differentiation in a reversibl...
(A–C) WT LSK cells were plated in semisolid media containing PU.1 inhibitors (25 μM for DB1976, 700 nM for DB2115, and 330 nM for DB2313). (A) Number of CFU-G, CFU-M, CFU-GM, CFU-GEMM, B/CFU-E, and immature colonies after treatment (left). Detailed histograms of CFU-GM, CFU-G, and CFU-M numbers (right) (n = 3). (B) Morphological appearance of cytospun and May-Grünwald Giemsa–stained cells after colony formation assay with vehicle or DB2313 treatment. Scale bars: 20 μm. (C) FACS analysis showing the percentage of CD11b+Gr1–, CD11b+Gr1+, CD11b–Gr1+, CD41+Ter119–, CD41+Ter119+, and CD41–Ter119+ cells after colony formation assays (n = 4). (D and E) Cells from a first round of colony formation assays treated with DB2313 were replated in the presence (+DB2313) or absence (–DB2313) of DB2313. (D) Representative FACS plots. (E) Proportion of CD11b+Gr1– and CD11b+Gr1+ cells formed, with or without DB2313 treatment, in the replating (n = 3). Fold change compared with replating with DB2313 treatment is shown. (F) Serial replating assay with D2313 continuous treatment (n = 3). *P < 0.05, **P < 0.01, and ****P < 0.0001, by 1-way ANOVA (A and C) or 2-tailed Student’s t test (E).