HOXA9 transcription factor as a target in acute myeloid leukemia: Transcription, cellular and in vivo consequences of its invalidation

Abstract Background: Acute myeloid leukemia (AML) is an aggressive malignancy characterized by clonal expansion of transformed myeloid precursors that fail to differentiate into mature cells. Since myeloid lineage maturation curbs self-renewal and is considered irreversible, engaging this process in AML is an attractive therapeutic strategy. Results: Normal myeloid differentiation requires the transcription factor PU.1 (SPI1), which is functionally compromised in several AML subtypes and is directly inhibited by the recurrent fusion oncoproteins AML1-ETO and PML-RARA. To examine the importance of PU.1 suppression in AML maintenance in vivo, we have combined RNAi-mediated PU.1 inhibition with p53 deficiency to drive highly aggressive AML in mice. Using these models we find that restoring endogenous PU.1 activity in established AML in vivo is sufficient to trigger robust transcriptional, immunophenotypic, and morphological differentiation of leukemic blasts, yielding polymorphonuclear, neutrophil-like cells. Maturation of AML is associated with significant loss of cell viability and yields sustained disease clearance in vivo. Although PU.1 restoration is potently anti-leukemic, remarkably we find that subsequent suppression of PU.1 in mature neutrophil-like cells reverts them to a transformed state within several days. While mature AML-derived cells are slower to form blast colonies in methylcellulose cultures, their clonogenic frequency is only reduced four-fold relative to AML blasts suggesting highly efficient de-differentiation. Conclusions: These results demonstrate that triggering myeloid differentiation can effectively resolve a p53-deficient model of treatment resistant AML, but also identify a previously unrecognised ability of AML cells to bidirectionally transition between transformed and differentiated states based on the activity of a single transcription factor. Our findings challenge the concept of 'terminal differentiation' in AML and highlight the importance of therapeutically eradicating leukemia cells at all stages of myeloid lineage maturation. Disclosures No relevant conflicts of interest to declare.

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Transcription Factor MEF2D is Required for the Maintenance of MLL-rearranged Acute Myeloid Leukemia

Blood Advances ◽

10.1182/bloodadvances.2021004469 ◽

2021 ◽

Author(s):

Lianzhong Zhao ◽

Pengcheng Zhang ◽

Phillip M Galbo ◽

Xinyue Zhou ◽

Sajesan Aryal ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Transcription Factor ◽

Myeloid Leukemia ◽

Critical Role ◽

Leukemia Cell ◽

Myeloid Differentiation ◽

Growth Defect ◽

Strong Negative Correlation ◽

Acute Myeloid

Acute myeloid leukemia (AML) with MLL-rearrangement (MLL-r) comprises approximately 10% of all AML cases and portends poor outcomes. Much remains uncovered on how MLL-r AML drives leukemia development while preventing cells from normal myeloid differentiation. Here, we identified that transcription factor MEF2D is a super-enhancer-associated, highly expressed gene in MLL-r AML. Knockout of MEF2D profoundly impaired leukemia growth, induced myeloid differentiation, and delayed oncogenic progression in vivo. Mechanistically, MEF2D loss led to robust activation of a CEBPE-centered myeloid differentiation program in AML cells. Chromatin profiling revealed that MEF2D binds to and suppresses the chromatin accessibility of CEBPE cis-regulatory regions. In human acute leukemia samples, MEF2D expression showed a strong negative correlation with the expression of CEBPE. Depletion of CEBPE partially rescued the cell growth defect and myeloid cell differentiation induced by the loss of MEF2D. Lastly, we show that MEF2D is positively regulated by HOXA9, and downregulation of MEF2D is an important mechanism for DOT1L inhibitor-induced anti-leukemia effects. Collectively, our findings suggest that MEF2D plays a critical role in human MLL-r AML and uncover the MEF2D-CEBPE axis as a crucial transcriptional mechanism regulating leukemia cell self-renewal and differentiation block.

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Salt-inducible kinase inhibition suppresses acute myeloid leukemia progression in vivo

Blood ◽

10.1182/blood.2019001576 ◽

2020 ◽

Vol 135 (1) ◽

pp. 56-70 ◽

Cited By ~ 6

Author(s):

Yusuke Tarumoto ◽

Shan Lin ◽

Jinhua Wang ◽

Joseph P. Milazzo ◽

Yali Xu ◽

...

Keyword(s):

Cell Proliferation ◽

Acute Myeloid Leukemia ◽

Transcription Factor ◽

Transcription Factors ◽

Small Molecule ◽

Myeloid Leukemia ◽

Kinase Inhibition ◽

Acute Myeloid ◽

In Cells

Transcription factors are important drivers in acute myeloid leukemia (AML), but they are notoriously difficult to target. The authors demonstrate that inhibition of salt-inducible kinase (SIK3) inhibits AML cell proliferation in cells dependent on the transcription factor MEF2C, identifying a small molecule that can disrupt a leukemogenic transcription factor pathway.

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CUX1 is a haploinsufficient tumor suppressor gene on chromosome 7 frequently inactivated in acute myeloid leukemia

Blood ◽

10.1182/blood-2012-04-426965 ◽

2013 ◽

Vol 121 (6) ◽

pp. 975-983 ◽

Cited By ~ 88

Author(s):

Megan E. McNerney ◽

Christopher D. Brown ◽

Xiaoyue Wang ◽

Elizabeth T. Bartom ◽

Subhradip Karmakar ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Transcription Factor ◽

Drosophila Melanogaster ◽

High Risk ◽

Myeloid Leukemia ◽

Suppressor Gene ◽

Chromosome 7 ◽

Key Points ◽

Acute Myeloid

Key Points CUX1 is a transcription factor encoded on a region of chromosome 7 that is frequently deleted in high-risk acute myeloid leukemia. Haploinsufficiency of CUX1/cut promotes hematopoietic overgrowth in both Drosophila melanogaster and human xenograft mouse models in vivo.

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Review for "Expanded clinical‐grade membrane‐bound IL‐21/4‐1BBL NK cell products exhibit activity against acute myeloid leukemia in vivo"

10.1002/eji.201948375/v1/review1 ◽

2019 ◽

Author(s):

Nicolas Dulphy

Keyword(s):

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Nk Cell ◽

Clinical Grade ◽

Membrane Bound ◽

Acute Myeloid

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Proteomic Studies of Primary Acute Myeloid Leukemia Cells Derived from Patients Before and during Disease-Stabilizing Treatment Based on All-Trans Retinoic Acid and Valproic Acid

Cancers ◽

10.3390/cancers13092143 ◽

2021 ◽

Vol 13 (9) ◽

pp. 2143

Author(s):

Maria Hernandez-Valladares ◽

Rebecca Wangen ◽

Elise Aasebø ◽

Håkon Reikvam ◽

Frode S. Berven ◽

...

Keyword(s):

Valproic Acid ◽

Acute Myeloid Leukemia ◽

Retinoic Acid ◽

Protein Kinase ◽

Myeloid Leukemia ◽

Rna Metabolism ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid ◽

Acute Myeloid

All-trans retinoic acid (ATRA) and valproic acid (VP) have been tried in the treatment of non-promyelocytic variants of acute myeloid leukemia (AML). Non-randomized studies suggest that the two drugs can stabilize AML and improve normal peripheral blood cell counts. In this context, we used a proteomic/phosphoproteomic strategy to investigate the in vivo effects of ATRA/VP on human AML cells. Before starting the combined treatment, AML responders showed increased levels of several proteins, especially those involved in neutrophil degranulation/differentiation, M phase regulation and the interconversion of nucleotide di- and triphosphates (i.e., DNA synthesis and binding). Several among the differentially regulated phosphorylation sites reflected differences in the regulation of RNA metabolism and apoptotic events at the same time point. These effects were mainly caused by increased cyclin dependent kinase 1 and 2 (CDK1/2), LIM domain kinase 1 and 2 (LIMK1/2), mitogen-activated protein kinase 7 (MAPK7) and protein kinase C delta (PRKCD) activity in responder cells. An extensive effect of in vivo treatment with ATRA/VP was the altered level and phosphorylation of proteins involved in the regulation of transcription/translation/RNA metabolism, especially in non-responders, but the regulation of cell metabolism, immune system and cytoskeletal functions were also affected. Our analysis of serial samples during the first week of treatment suggest that proteomic and phosphoproteomic profiling can be used for the early identification of responders to ATRA/VP-based treatment.

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Potentially Curative Therapeutic Activity of NEO212, a Perillyl Alcohol-Temozolomide Conjugate, in Preclinical Cytarabine-Resistant Models of Acute Myeloid Leukemia

Cancers ◽

10.3390/cancers13143385 ◽

2021 ◽

Vol 13 (14) ◽

pp. 3385

Author(s):

Axel H. Schönthal ◽

Steve Swenson ◽

Radu O. Minea ◽

Hye Na Kim ◽

Heeyeon Cho ◽

...

Keyword(s):

Cell Death ◽

Acute Myeloid Leukemia ◽

Side Effects ◽

Anticancer Activity ◽

Myeloid Leukemia ◽

Perillyl Alcohol ◽

Therapeutic Activity ◽

Acute Myeloid

Despite progress in the treatment of acute myeloid leukemia (AML), the clinical outcome remains suboptimal and many patients are still dying from this disease. First-line treatment consists of chemotherapy, which typically includes cytarabine (AraC), either alone or in combination with anthracyclines, but drug resistance can develop and significantly worsen prognosis. Better treatments are needed. We are developing a novel anticancer compound, NEO212, that was created by covalent conjugation of two different molecules with already established anticancer activity, the alkylating agent temozolomide (TMZ) and the natural monoterpene perillyl alcohol (POH). We investigated the anticancer activity of NEO212 in several in vitro and in vivo models of AML. Human HL60 and U937 AML cell lines, as well as different AraC-resistant AML cell lines, were treated with NEO212 and effects on cell proliferation, cell cycle, and cell death were investigated. Mice with implanted AraC-sensitive or AraC-resistant AML cells were dosed with oral NEO212, and animal survival was monitored. Our in vitro experiments show that treatment of cells with NEO212 results in growth inhibition via potent G2 arrest, which is followed by apoptotic cell death. Intriguingly, NEO212 was equally potent in highly AraC-resistant cells. In vivo, NEO212 treatment strikingly extended survival of AML mice and the majority of treated mice continued to thrive and survive without any signs of illness. At the same time, we were unable to detect toxic side effects of NEO212 treatment. All in all, the absence of side effects, combined with striking therapeutic activity even in an AraC-resistant context, suggests that NEO212 should be developed further toward clinical testing.

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Decitabine induces very early in vivo DNA methylation changes in blasts from patients with acute myeloid leukemia

Leukemia Research ◽

10.1016/j.leukres.2012.10.015 ◽

2013 ◽

Vol 37 (2) ◽

pp. 190-196 ◽

Cited By ~ 20

Author(s):

Rainer Claus ◽

Dietmar Pfeifer ◽

Maika Almstedt ◽

Manuela Zucknick ◽

Björn Hackanson ◽

...

Keyword(s):

Dna Methylation ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Acute Myeloid

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ATM/G6PD-driven redox metabolism promotes FLT3 inhibitor resistance in acute myeloid leukemia

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1603876113 ◽

2016 ◽

Vol 113 (43) ◽

pp. E6669-E6678 ◽

Cited By ~ 35

Author(s):

Mark A. Gregory ◽

Angelo D’Alessandro ◽

Francesca Alvarez-Calderon ◽

Jihye Kim ◽

Travis Nemkov ◽

...

Keyword(s):

Oxidative Stress ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Mitochondrial Oxidative Stress ◽

Flt3 Inhibitor ◽

A Genome ◽

Flt3 Inhibitors ◽

Acute Myeloid

Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are common in acute myeloid leukemia (AML) and drive leukemic cell growth and survival. Although FLT3 inhibitors have shown considerable promise for the treatment of AML, they ultimately fail to achieve long-term remissions as monotherapy. To identify genetic targets that can sensitize AML cells to killing by FLT3 inhibitors, we performed a genome-wide RNA interference (RNAi)-based screen that identified ATM (ataxia telangiectasia mutated) as being synthetic lethal with FLT3 inhibitor therapy. We found that inactivating ATM or its downstream effector glucose 6-phosphate dehydrogenase (G6PD) sensitizes AML cells to FLT3 inhibitor induced apoptosis. Examination of the cellular metabolome showed that FLT3 inhibition by itself causes profound alterations in central carbon metabolism, resulting in impaired production of the antioxidant factor glutathione, which was further impaired by ATM or G6PD inactivation. Moreover, FLT3 inhibition elicited severe mitochondrial oxidative stress that is causative in apoptosis and is exacerbated by ATM/G6PD inhibition. The use of an agent that intensifies mitochondrial oxidative stress in combination with a FLT3 inhibitor augmented elimination of AML cells in vitro and in vivo, revealing a therapeutic strategy for the improved treatment of FLT3 mutated AML.

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