bims-tremyl 2022-12-04 papers

bims-tremyl

Biomed News

on Therapy resistance biology in myeloid leukemia

Issue of 2022–12–04
38 papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London

Mutant NPM1 directly regulates oncogenic transcription in acute myeloid leukemia.
Prognostic implications of mono-hit and multi-hit TP53 alterations in patients with acute myeloid leukemia and higher risk myelodysplastic syndromes treated with azacitidine-based therapy.
Comparison and validation of the 2022 European LeukemiaNet guidelines in acute myeloid leukemia.
Activation of the PP2A-B56α heterocomplex synergizes with venetoclax therapies in AML through BCL2 and MCL1 modulation.
A retrospective study of cladribine and low-dose cytarabine-based regimens for the treatment of chronic myelomonocytic leukemia and secondary acute myeloid leukemia.
Decitabine Versus Hydroxyurea for Advanced Proliferative Chronic Myelomonocytic Leukemia: Results of a Randomized Phase III Trial Within the EMSCO Network.
Retained functional normal and preleukemic HSCs at diagnosis are associated to good prognosis in DNMT3Amut NPM1mut AMLs.
Paired bone marrow and peripheral blood samples demonstrate lack of widespread dissemination of some CH clones.
Cellular distribution of IDH mutations in AML during morphologic remission.
IMPDH inhibition activates TLR-VCAM1 pathway and suppresses the development of MLL-fusion leukemia.
TNF Receptors Choose HSC Fate in Supporting Dnmt3a-Mutant Clonal Hematopoiesis.
UBTF-Internal tandem duplication as a novel poor prognostic factor in pediatric acute myeloid leukemia.
Mutant NPM1 hijacks transcriptional hub to maintain pathogenic gene programs in acute myeloid leukemia.
The present and future of measurable residual disease testing in acute myeloid leukemia.
Activation of orphan receptor GPR132 induces cell differentiation in acute myeloid leukemia.
The ENL YEATS epigenetic reader domain critically links MLL-ENL to leukemic stem cell frequency in t(11;19) Leukemia.
SETD1A regulates transcriptional pause release of heme biosynthesis genes in leukemia.
Electrostatic anti-CD33-antibody-protamine nanocarriers as platform for a targeted treatment of acute myeloid leukemia.
Total body irradiation plus fludarabine versus busulfan plus fludarabine as a myeloablative conditioning for adults with acute myeloid leukemia treated with allogeneic hematopoietic cell transplantation. A study on behalf of the Acute Leukemia Working Party of the EBMT.
Disrupting PTPRJ transmembrane-mediated oligomerization counteracts oncogenic receptor tyrosine kinase FLT3 ITD.
Targeting integrated stress response with ISRIB combined with imatinib treatment attenuates RAS/RAF/MAPK and STAT5 signaling and eradicates chronic myeloid leukemia cells.
Treatment response in acute myeloid leukaemia-Clues in the biopsy core.
Associations of clonal haematopoiesis with recurrent vascular events and death in patients with incident ischemic stroke.
Distinct mutational and clinicopathologic profiles characterize acute myeloid leukemia with cup-like nuclei.
Transient regulation of RNA methylation in human hematopoietic stem cells promotes their homing and engraftment.
PCGF1-PRC1 links chromatin repression with DNA replication during hematopoietic cell lineage commitment.
Somatic TP53 mutations are pre-leukemic events in acute lymphoblastic leukemia.
Genomic signature of Fanconi anaemia DNA repair pathway deficiency in cancer.
Clonal Hematopoiesis and Its Impact on Human Health.
Ras drives malignancy through stem cell crosstalk with the microenvironment.
Haploidentical bone marrow transplants with post transplant cyclophosphamide on day + 3 + 5: The Genova protocol.
Comprehensive analysis of ID genes reveals the clinical and prognostic value of ID3 expression in acute myeloid leukemia using bioinformatics identification and experimental validation.
DDX41-associated susceptibility to myeloid neoplasms.
Cord blood transplantation for nonmalignant disorders: early functional immunity and high survival.
A sex-informed approach to improve the personalised decision making process in myelodysplastic syndromes: a multicentre, observational cohort study.
The indispensable role of the RNA helicase DDX5 in tumorigenesis induced by the myeloproliferative neoplasm-associated JAK2V617F mutant.
Correction: TP53-Mutated Myelodysplastic Syndrome and Acute Myeloid Leukemia: Biology, Current Therapy, and Future Directions.
PPM1D suppresses p53-dependent transactivation and cell death by inhibiting the Integrated Stress Response.

Cancer Discov. 2022 Dec 01. pii: CD-22-0366. [Epub ahead of print]

Mutant NPM1 directly regulates oncogenic transcription in acute myeloid leukemia.

Hannah J Uckelmann, Elena L Haarer, Reina Takeda, Eric M Wong, Charlie Hatton, Christian Marinaccio, Florian Perner, Masooma Rajput, Noa J C Antonissen, Yanhe Wen, Lu Yang, Lorenzo Brunetti, Chun-Wei Chen, Scott A Armstrong.

The dysregulation of developmental and stem cell associated genes is a common phenomenon during cancer development. Around half of acute myeloid leukemia (AML) patients express high levels of HOXA cluster genes and MEIS1. Most of these AML cases harbor an NPM1 mutation (NPM1c), which encodes for an oncogene mislocalized from the nucleolus to the cytoplasm. How NPM1c expression in hematopoietic cells leads to its characteristic gene expression pattern remains unclear. Here, we show that NPM1c directly binds to specific chromatin targets, which are co-occupied by the histone methyltransferase KMT2A (MLL1). Targeted degradation of NPM1c leads to a rapid decrease in gene expression and loss of RNA Polymerase II, as well as activating histone modifications at its targets. We demonstrate that NPM1c directly regulates oncogenic gene expression in collaboration with the MLL1 complex and define the mechanism by which MLL1-Menin small molecule inhibitors produce clinical responses in patients with NPM1-mutated AML.

DOI: https://doi.org/10.1158/2159-8290.CD-22-0366
Leukemia. 2022 Nov 27.

Prognostic implications of mono-hit and multi-hit TP53 alterations in patients with acute myeloid leukemia and higher risk myelodysplastic syndromes treated with azacitidine-based therapy.

Amer M Zeidan, Jan Philipp Bewersdorf, Vanessa Hasle, Rory M Shallis, Ethan Thompson, Daniel Lopes de Menezes, Shelonidta Rose, Isaac Boss, Stephanie Halene, Torsten Haferlach, Brian Fox.

DOI: https://doi.org/10.1038/s41375-022-01766-z
Blood Adv. 2022 Nov 28. pii: bloodadvances.2022009010. [Epub ahead of print]

Comparison and validation of the 2022 European LeukemiaNet guidelines in acute myeloid leukemia.

Curtis A Lachowiez, Nicola Long, Jennifer N Saultz, Arpita Gandhi, Laura F Newell, Brandon Hayes-Lattin, Richard T Maziarz, Jessica Leonard, Daniel Bottomly, Shannon K McWeeney, Jennifer Dunlap, Richard D Press, Gabrielle Meyers, Ronan Swords, Rachel Cook, Jeffrey W Tyner, Brian J Druker, Elie Traer.

Risk stratification in acute myeloid leukemia (AML) remains principle for survival prognostication and treatment selection. The 2022 European LeukemiaNet (ELN) recommendations were recently published, with notable updates to risk group assignment. The complexity of risk stratification and comparative outcomes between the 2022 and 2017 ELN guidelines remains unknown. This comparative analysis evaluated outcomes between the 2017 and 2022 ELN criteria in patients enrolled within the multi-center Beat AML cohort. Five-hundred thirteen patients were included. Most patients had one (36% [N=183]) or two (31% [N=159]) ELN risk-defining abnormalities. In patients with two or more ELN-risk defining mutations (58% [N=297]), 44% (N=132) had mutations spanning multiple ELN risk categories. Compared to ELN 2017 criteria, the updated ELN 2022 guidelines changed assigned risk group in 15% (N=75) of patients, including 10% (N=16/160), 26% (N=29/112), and 6% (N=13/224) of ELN 2017 favorable, intermediate, and adverse-risk patients. Median OS across ELN 2022 favorable, intermediate, and adverse-risk groups was not reached (estimated 5-year OS: 53% [standard error: 0.06%]), 16.8 (95% CI: 11-48) and 9.7 (95% CI: 8.3-10.8) months, respectively. The ELN 2022 guidelines more accurately stratified survival between patients with intermediate or adverse-risk AML treated with IC (HR: 1.58 [95% CI: 1.12-2.25], p-value: 0.01) compared to ELN 2017 guidelines (HR 1.27 [95% CI: 0.88-1.85], p-value: 0.20). The updated ELN 2022 guidelines better stratify survival, namely between patients with intermediate or adverse-risk AML treated with IC. The increased complexity of risk stratification with inclusion of additional cytogenetic and molecular aberrations necessitates clinical workflows simplifying risk stratification.

DOI: https://doi.org/10.1182/bloodadvances.2022009010
Blood. 2022 Dec 01. pii: blood.2022016466. [Epub ahead of print]

Activation of the PP2A-B56α heterocomplex synergizes with venetoclax therapies in AML through BCL2 and MCL1 modulation.

Irene Peris, Silvia Romero-Murillo, Elena Martínez-Balsalobre, Caroline C Farrington, Elena Arriazu, Nerea Marcotegui, Marta Jiménez-Muñoz, Cristina Alburquerque-Prieto, Andrea Torres-López, Vicente Jose Fresquet, Jose-Angel Martinez-Climent, Maria C Mateos, Maria Luisa Cayuela, Goutham Narla, Maria D Odero, Carmen Vicente.

Venetoclax-combination therapies are becoming the standard-of-care in acute myeloid leukemia (AML). However, the therapeutic benefit of these drugs in older/unfit patients is limited to only a few months, highlighting the need for more effective therapies. PP2A is a tumor suppressor phosphatase with pleiotropic functions that becomes inactivated in ~70% of AML cases. PP2A promotes cancer cell death by modulating the phosphorylation state in a variety of proteins along the mitochondrial apoptotic pathway. We therefore hypothesized that pharmacological PP2A reactivation could increase BCL2 dependency in AML cells and thus potentiate venetoclax-induced cell death. Here, by using three structurally distinct PP2A-activating drugs, we show that PP2A reactivation synergistically enhances venetoclax activity in AML cell lines, primary cells, and xenograft models. Through the use of CRISPR-Cas9 models and pharmacologic approaches, we demonstrate that the observed therapeutic synergy relies on PP2A complexes containing the B56α regulatory subunit, which expression dictates response to the combination therapy. Mechanistically, PP2A reactivation enhances venetoclax-driven apoptosis through simultaneous inhibition of anti-apoptotic BCL2 and ERK signaling, the later decreasing MCL1 protein stability. Finally, PP2A targeting increases the efficacy of the clinically approved venetoclax and azacitidine combination in vitro, in primary cells, and in an AML patient-derived xenograft model. These preclinical results provide a scientific rationale for testing PP2A-activating drugs with venetoclax combinations in AML.

DOI: https://doi.org/10.1182/blood.2022016466
Cancer. 2022 Dec 02.

A retrospective study of cladribine and low-dose cytarabine-based regimens for the treatment of chronic myelomonocytic leukemia and secondary acute myeloid leukemia.

Alexandre Bazinet, Faezeh Darbaniyan, Tapan M Kadia, Sangeetha Venugopal, Rashmi Kanagal-Shamanna, Courtney D DiNardo, Gautam Borthakur, Elias J Jabbour, Naval G Daver, Naveen Pemmaraju, Marina Y Konopleva, Farhad Ravandi, Koji Sasaki, Kelly S Chien, Danielle Hammond, Sherry A Pierce, Hagop M Kantarjian, Guillermo Garcia-Manero, Guillermo Montalban-Bravo.

   BACKGROUND: Patients with higher risk chronic myelomonocytic leukemia (CMML) have limited therapeutic options beyond hydroxyurea and hypomethylating agents (HMAs). Regimens based on a backbone of cladribine (CLAD), low-dose cytarabine (LDAC), and an HMA are effective low-intensity therapies for acute myeloid leukemia (AML).
METHODS: The authors conducted a retrospective chart review to evaluate the efficacy of CLAD/LDAC/HMA in CMML and secondary acute myeloid leukemia (sAML) arising from CMML. Responses were evaluated according to the 2006 International Working Group criteria for CMML and the 2017 European LeukemiaNet criteria for AML. The overall survival (OS), leukemia-free survival (LFS), and duration of response were evaluated with the Kaplan-Meier method. Patients were stratified on the basis of prior HMA exposure.
RESULTS: The authors identified 21 patients with CMML (eight with HMA-naive CMML and 13 with HMA-failure CMML) and 33 patients with sAML (11 with HMA-naive sAML and 22 with HMA-failure sAML) treated with CLAD/LDAC/HMA-based regimens. The CMML cohort was enriched for high-risk features (proliferative type, elevated blasts, and RAS/MAPK mutations). The overall response rate was 33% in CMML (50% in HMA-naive CMML and 23% in HMA-failure CMML) and 48% in sAML (82% in HMA-naive sAML and 32% in HMA-failure sAML). The median OS was 14.4, 8.8, 42.9, and 2.9 months for HMA-naive CMML, HMA-failure CMML, HMA-naive sAML, and HMA-failure sAML, respectively. The median LFS was 14.4 and 3.9 months for HMA-naive CMML and HMA-failure CMML, respectively.
CONCLUSIONS: CLAD/LDAC/HMA-based regimens are effective in a subset of patients with higher risk CMML and sAML arising from CMML who have not previously experienced HMA failure. These findings must be confirmed in prospective studies.

Keywords:  acute myeloid leukemia; chronic myelomonocytic leukemia; cladribine; cytarabine; hypomethylating agents

DOI:  https://doi.org/10.1002/cncr.34564
J Clin Oncol. 2022 Dec 01. JCO2200437

Decitabine Versus Hydroxyurea for Advanced Proliferative Chronic Myelomonocytic Leukemia: Results of a Randomized Phase III Trial Within the EMSCO Network.

Raphael Itzykson, Valeria Santini, Sylvain Thepot, Lionel Ades, Cendrine Chaffaut, Aristoteles Giagounidis, Margot Morabito, Nathalie Droin, Michael Lübbert, Rosa Sapena, Stanislas Nimubona, Jean Goasguen, Eric Wattel, Gina Zini, Jose Miguel Torregrosa Diaz, Ulrich Germing, Anna Maria Pelizzari, Sophie Park, Nadja Jaekel, Georgia Metzgeroth, Francesco Onida, Robert Navarro, Andrea Patriarca, Aspasia Stamatoullas, Katharina Götze, Martin Puttrich, Sandra Mossuto, Eric Solary, Silke Gloaguen, Sylvie Chevret, Fatiha Chermat, Uwe Platzbecker, Pierre Fenaux.

PURPOSE: Hydroxyurea (HY) is a reference treatment of advanced myeloproliferative neoplasms. We conducted a randomized phase III trial comparing decitabine (DAC) and HY in advanced myeloproliferative chronic myelomonocytic leukemias (CMML).
PATIENTS AND METHODS: Newly diagnosed myeloproliferative CMML patients with advanced disease were randomly assigned 1:1 to intravenous DAC (20 mg/m2/d days 1-5) or HY (1-4 g/d) in 28-day cycles. The primary end point was event-free survival (EFS), events being death and acute myelomonocytic leukemia (AML) transformation or progression.
RESULTS: One-hundred seventy patients received DAC (n = 84) or HY (n = 86). Median age was 72 and 74 years, and median WBC count 32.5 × 109/L and 31.2 × 109/L in the DAC and HY arms, respectively. Thirty-three percent of DAC and 31% of HY patients had CMML-2. Patients received a median of five DAC and six HY cycles. With a median follow-up of 17.5 months, median EFS was 12.1 months in the DAC arm and 10.3 months in the HY arm (hazard ratio [HR], 0.83; 95% CI, 0.59 to 1.16; P = .27). There was no significant interaction between treatment effect and blast or platelet count, anemia, CMML Prognostic Scoring System, Groupe Francophone des Myelodysplasies, or CMML Prognostic Scoring System-mol risk. Fifty-three (63%) DAC patients achieved a response compared with 30 (35%) HY patients (P = .0004). Median duration of response was similar in both arms (DAC, 16.3 months; HY, 17.4 months; P = .90). Median overall survival was 18.4 months in the DAC arm and 21.9 months in the HY arm (P = .67). Compared with HY, DAC significantly reduced the risk of CMML progression or transformation to acute myelomonocytic leukemia (cause-specific HR, 0.62; 95% CI, 0.41 to 0.94; P = .005) at the expense of death without progression or transformation (cause-specific HR, 1.55; 95% CI, 0.82 to 2.9; P = .04).
CONCLUSION: Compared with HY, frontline treatment with DAC did not improve EFS in patients with advanced myeloproliferative CMML (ClinicalTrials.gov identifier: NCT02214407).

DOI: https://doi.org/10.1200/JCO.22.00437
Blood Adv. 2022 12 01. pii: bloodadvances.2022008497. [Epub ahead of print]

Retained functional normal and preleukemic HSCs at diagnosis are associated to good prognosis in DNMT3Amut NPM1mut AMLs.

Elisa Donato, Nadia C Correia, Carolin Andresen, Darja Karpova, Roberto Würth, Corinna Klein, Markus Sohn, Adriana Przybylla, Petra Zeisberger, Kathrin Rothfelder, Helmut R Salih, Halvard Bonig, Sebastian Stasik, Christoph Röllig, Anna Dolnik, Lars Bullinger, Frank Buchholz, Christian Thiede, Daniel Hübschmann, Andreas Trumpp.

AML is a heterogeneous disease characterized by high rate of relapse and mortality. While chemotherapies may eradicate blasts, they are less effective in eliminating relapse-causing Leukemic Stem Cells (LSCs). Although LSCs are usually identified as CD34+CD38- cells, there is significant heterogeneity in surface marker expression and CD34- LSCs exist particularly in NPM1mut AMLs. By analyzing diagnostic primary DNMT3AmutNPM1mut AML samples, we suggest a novel flow cytometry sorting strategy particularly useful for CD34neg AML subtypes. To enrich for LSCs independently of CD34 status, positive selection for GPR56 and negative selection for NKG2D-Ligands are employed. We demonstrate that the functional reconstitution capacity of CD34- and CD34+ LSCs as well as their transcriptomes are very similar supporting phenotypic plasticity. Furthermore, we show that while CD34+ subpopulations can contain next to LSCs also normal and/or pre-leukemic Hematopoietic Stem Cells (HSCs), this is not the case in CD34-GPR56+NKG2DL- enriched LSCs which thus can be isolated with high purity. Finally, we show that AML patients, who retain at time of diagnosis a reserve of normal and/or preleukemic HSCs in their bone marrow able to reconstitute immunocompromised mice, have significant longer relapse-free and overall survival compared to AML patients in whom functional HSCs are no longer detectable.

DOI: https://doi.org/10.1182/bloodadvances.2022008497
Blood Adv. 2022 Dec 01. pii: bloodadvances.2022008521. [Epub ahead of print]

Paired bone marrow and peripheral blood samples demonstrate lack of widespread dissemination of some CH clones.

Afaf Osman, Nuria Mencia-Trinchant, Caner Saygin, Luke Moma, Aelin Kim, Genevieve Housman, Matthew J Pozsgai, Eti Sinha, Pooja Chandra, Duane C Hassane, Andrea Sboner, Kishan Sangani, Nick DiNardi, Christopher Johnson, Sara S Wallace, Bana Jabri, Hue Luu, Monica L Guzman, Pinkal Desai, Lucy A Godley.

Clonal hematopoiesis (CH) represents clonal expansion of mutated hematopoietic stem cells detectable in the peripheral blood or bone marrow through next generation sequencing. The current prevailing model posits that CH mutations detected in the peripheral blood mirror bone marrow mutations with clones widely disseminated across hematopoietic compartments. We sought to test the hypothesis that all clones are disseminated throughout hematopoietic tissues by comparing CH in hip versus peripheral blood specimens collected at the time of hip replacement surgery. Here, we show that patients with osteoarthritis have a high prevalence of CH, involving genes encoding epigenetic modifiers and DNA damage repair pathway proteins. Importantly, we illustrate that CH, including clones with variant allele frequencies >10%, can be confined to specific bone marrow spaces and may be eliminated through surgical excision. Future work will define whether clones with somatic mutations in particular genes or clonal fractions of certain sizes are more likely to be localized or are slower to disseminate into the peripheral blood and other bony sites.

DOI: https://doi.org/10.1182/bloodadvances.2022008521
Leuk Res. 2022 Nov 25. pii: S0145-2126(22)00369-1. [Epub ahead of print]124 106993

Cellular distribution of IDH mutations in AML during morphologic remission.

Radha Ramanan, Ing Soo Tiong, Adam Ivey, Doen Ming Ong, Fiona C Brown, Chyn Chua, Tongted Das, David Curtis.

  Limited information exists about the cellular distribution of mutations which persist in remission in acute myeloid leukemia (AML) (variable considered pre-leukemic mutations). We hypothesized that mutations detectable in all cell compartments may be less pathogenic than those that are myeloid-restricted. Here, we describe the cellular compartments that have IDH mutations in five patients with IDH-mutated AML in morphologic remission. Unlike pre-leukemic clones harboring the more common DNMT3A, TET2 and ASXL1 (DTA) mutations, we show that IDH mutations are myeloid-restricted. This finding provides an explanation for the reports that IDH mutations carry a higher risk for relapse than DTA mutations. Detailed analysis of one case also shows acquisition of additional mutations in distinct cellular compartments, illustrating subclonal complexity associated with therapeutics.

Keywords:  AML; Cellular distribution; IDH; Preleukemic; Remission

DOI:  https://doi.org/10.1016/j.leukres.2022.106993
EMBO Mol Med. 2022 Dec 01. e15631

IMPDH inhibition activates TLR-VCAM1 pathway and suppresses the development of MLL-fusion leukemia.

Xiaoxiao Liu, Naru Sato, Tomohiro Yabushita, Jingmei Li, Yuhan Jia, Moe Tamura, Shuhei Asada, Takeshi Fujino, Tsuyoshi Fukushima, Taishi Yonezawa, Yosuke Tanaka, Tomofusa Fukuyama, Akiho Tsuchiya, Shiori Shikata, Hiroyuki Iwamura, Chieko Kinouchi, Kensuke Komatsu, Satoshi Yamasaki, Tatsuhiro Shibata, Atsuo T Sasaki, Janet Schibler, Mark Wunderlich, Eric O'Brien, Benjamin Mizukawa, James C Mulloy, Yuki Sugiura, Hitoshi Takizawa, Takuma Shibata, Kensuke Miyake, Toshio Kitamura, Susumu Goyama.

  Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in de novo guanine nucleotide synthesis pathway. Although IMPDH inhibitors are widely used as effective immunosuppressants, their antitumor effects have not been proven in the clinical setting. Here, we found that acute myeloid leukemias (AMLs) with MLL-fusions are susceptible to IMPDH inhibitors in vitro. We also showed that alternate-day administration of IMPDH inhibitors suppressed the development of MLL-AF9-driven AML in vivo without having a devastating effect on immune function. Mechanistically, IMPDH inhibition induced overactivation of Toll-like receptor (TLR)-TRAF6-NF-κB signaling and upregulation of an adhesion molecule VCAM1, which contribute to the antileukemia effect of IMPDH inhibitors. Consequently, combined treatment with IMPDH inhibitors and the TLR1/2 agonist effectively inhibited the development of MLL-fusion AML. These findings provide a rational basis for clinical testing of IMPDH inhibitors against MLL-fusion AMLs and potentially other aggressive tumors with active TLR signaling.

Keywords:  IMPDH inhibitor; MLL-fusion leukemia; TLR signaling; Vcam1

DOI:  https://doi.org/10.15252/emmm.202115631
Cancer Discov. 2022 Dec 02. 12(12): 2724-2726

TNF Receptors Choose HSC Fate in Supporting Dnmt3a-Mutant Clonal Hematopoiesis.

Katia E Niño, Eric M Pietras.

SUMMARY: TNFα receptor signaling distinctly promotes self-renewal and lymphoid differentiation in Dnmt3a-mutant hematopoietic stem cells, contributing to clonal hematopoiesis of indeterminate potential. See related article by SanMiguel et al., p. 2763 (3).

DOI: https://doi.org/10.1158/2159-8290.CD-22-1022
Genes Chromosomes Cancer. 2022 Nov 30.

UBTF-Internal tandem duplication as a novel poor prognostic factor in pediatric acute myeloid leukemia.

Taeko Kaburagi, Norio Shiba, Genki Yamato, Kenichi Yoshida, Ken Tabuchi, Kentaro Ohki, Etsuko Ishikita, Yusuke Hara, Yuichi Shiraishi, Hirohide Kawasaki, Manabu Sotomatsu, Takumi Takizawa, Tomohiko Taki, Nobutaka Kiyokawa, Daisuke Tomizawa, Keizo Horibe, Satoru Miyano, Takashi Taga, Souichi Adachi, Seishi Ogawa, Yasuhide Hayashi.

  The prognosis of pediatric acute myeloid leukemia (AML) has improved via stratification therapy. However, relapse or death occurs in 30%-40% of cases. Novel genetic factors for pediatric AML need to be elucidated to improve prognosis. We detected recurrent internal tandem duplication in upstream binding transcription factor (UBTF-ITD) in 1.2% (6/503) of Japanese pediatric patients with de novo AML. No UBTF-ITD was detected in 175 adult patients with AML or in 65 cell lines that included 15 AML, 39 acute lymphoblastic leukemia, 5 chronic myeloid leukemia, and 6 neuroblastoma cell lines. All UBTF-ITDs were found in exon 13 and shared a duplicated region. UBTF-ITD was more frequently detected in patients with trisomy 8, FLT3-ITD, WT1 mutation, and/or high PRDM16 expression (trisomy 8, 3/6; FLT3-ITD, 5/6; WT1 mutation, 2/6; and high PRDM16 expression, 6/6). Gene expression patterns of patients with UBTF-ITD were similar to those of patients with NUP98::NSD1 or FUS::ERG. Survival analysis of the AML-05 cohort revealed that patients with UBTF-ITD had worse outcomes than those without UBTF-ITD (3-year event-free survival, 20 % vs. 55 %; 3-year overall survival, 40 % vs. 74 %). Moreover, among the 27 patients with trisomy 8, all three patients with UBTF -ITD had a poor prognosis resulting in early events (relapse or non-complete remission) within one year. Our findings suggest that UBTF-ITD may be a novel and significant prognostic factor for pediatric patients with AML. This article is protected by copyright. All rights reserved.

Keywords:  AML; FLT3-ITD; PRDM16; UBTF-ITD; pediatric; trisomy 8

DOI:  https://doi.org/10.1002/gcc.23110
Cancer Discov. 2022 Dec 01. pii: CD-22-0424. [Epub ahead of print]

Mutant NPM1 hijacks transcriptional hub to maintain pathogenic gene programs in acute myeloid leukemia.

Xue Qing David Wang, Dandan Fan, Qinyu Han, Yiman Liu, Hongzhi Miao, Xinyu Wang, Qinglan Li, Dong Chen, Haley Gore, Pamela Himadewi, Gerd P Pfeifer, Tomasz Cierpicki, Jolanta Grembecka, Jianzhong Su, Shasha Chong, Liling Wan, Xiaotian Zhang.

Nucleophosmin (NPM1) is a ubiquitously expressed nucleolar protein with a wide range of biological functions. In 30% of acute myeloid leukemia (AML), the terminal exon of NPM1 is often found mutated, resulting in the addition of a nuclear export signal and a shift of the protein to the cytoplasm (NPM1c). AMLs carrying this mutation have aberrant expression of the HOXA/B genes, whose overexpression lead to leukemogenic transformation. Here, for the first time, we comprehensively prove NPM1c binds to a subset of active gene promoters in NPM1c AMLs, including well-known leukemia-driving genes - HOXA/B cluster genes and MEIS1. NPM1c sustains the active transcription of key target genes by orchestrating a transcription hub and maintains the active chromatin landscape by inhibiting the activity of histone deacetylases (HDACs). Together, these findings reveal the neomorphic function of NPM1c as a transcriptional amplifier for leukemic gene expression and open up new paradigms for therapeutic intervention.

DOI: https://doi.org/10.1158/2159-8290.CD-22-0424
Haematologica. 2022 Dec 01. 107(12): 2810-2822

The present and future of measurable residual disease testing in acute myeloid leukemia.

James S Blachly, Roland B Walter, Christopher S Hourigan.

Considerable progress has been made in the past several years in the scientific understanding of, and available treatments for, acute myeloid leukemia (AML). Achievement of a conventional remission, evaluated cytomorphologically via small bone marrow samples, is a necessary but not sufficient step toward cure. It is increasingly appreciated that molecular or immunophenotypic methods to identify and quantify measurable residual disease (MRD) - populations of leukemia cells below the cytomorphological detection limit - provide refined information on the quality of response to treatment and prediction of the risk of AML recurrence and leukemia-related deaths. The principles and practices surrounding MRD remain incompletely determined however and the genetic and immunophenotypic heterogeneity of AML may prevent a one-sizefits- all approach. Here, we review the current approaches to MRD testing in AML, discuss strengths and limitations, highlight recent technological advances that may improve such testing, and summarize ongoing initiatives to generate the clinical evidence needed to advance the use of MRD testing in patients with AML.

DOI: https://doi.org/10.3324/haematol.2022.282034
Cell Death Dis. 2022 Nov 27. 13(11): 1004

Activation of orphan receptor GPR132 induces cell differentiation in acute myeloid leukemia.

Chunyang Yi, Jiacheng He, Dan Huang, Yumiao Zhao, Chan Zhang, Xiyun Ye, Ying Huang, Ruth Nussinov, Junke Zheng, Mingyao Liu, Weiqiang Lu.

Blocked cellular differentiation is a critical pathologic hallmark of acute myeloid leukemia (AML). Here, we showed that genetic activation of the orphan GPCR GPR132 significantly induced cell differentiation of AML both in vitro and in vivo, indicating that GPR132 is a potential trigger of myeloid differentiation. To explore the therapeutic potential of GPR132 signaling, we screened and validated a natural product 8-gingerol (8GL) as a GPR132 agonist. Notably, GPR132 activation by 8GL promoted differentiation and reduced colony formation in human AML cell lines with diverse genetic profiles. Mechanistic studies revealed that 8GL treatment inhibits the activation of the mammalian target of rapamycin (mTOR), a regulator of AML cell differentiation blockade, via activating GPR132-Gs-PKA pathway. We further showed that the combination of 8GL and an mTOR inhibitor synergistically elicited AML cell differentiation in vitro. Importantly, 8GL alone or in combination with an mTOR inhibitor remarkably impaired tumor growth and extended mouse survival in an AML xenograft model accompanied by enhanced cell differentiation. Notably, genetic or pharmacological activation of GPR132 triggered the differentiation of human primary AML cells. In summary, this study demonstrated that activation of orphan GPR132 represents a potential strategy for inducing myeloid differentiation in AML patients.

DOI: https://doi.org/10.1038/s41419-022-05434-z
Leukemia. 2022 Nov 26.

The ENL YEATS epigenetic reader domain critically links MLL-ENL to leukemic stem cell frequency in t(11;19) Leukemia.

Hsiangyu Hu, Nirmalya Saha, Yuting Yang, Ejaz Ahmad, Lauren Lachowski, Uttar Shrestha, Vidhya Premkumar, James Ropa, Lili Chen, Blaine Teahan, Sierrah Grigsby, Rolf Marschalek, Zaneta Nikolovska-Coleska, Andrew G Muntean.

MLL (KMT2a) translocations are found in ~10% of acute leukemia patients, giving rise to oncogenic MLL-fusion proteins. A common MLL translocation partner is ENL and associated with a poor prognosis in t(11;19) patients. ENL contains a highly conserved N-terminal YEATS domain that binds acetylated histones and interacts with the PAF1c, an epigenetic regulator protein complex essential for MLL-fusion leukemogenesis. Recently, wild-type ENL, and specifically the YEATS domain, was shown to be essential for leukemic cell growth. However, the inclusion and importance of the YEATS domain in MLL-ENL-mediated leukemogenesis remains unexplored. We found the YEATS domain is retained in 84.1% of MLL-ENL patients and crucial for MLL-ENL-mediated leukemogenesis in mouse models. Mechanistically, deletion of the YEATS domain impaired MLL-ENL fusion protein binding and decreased expression of pro-leukemic genes like Eya1 and Meis1. Point mutations that disrupt YEATS domain binding to acetylated histones decreased stem cell frequency and increased MLL-ENL-mediated leukemia latency. Therapeutically, YEATS containing MLL-ENL leukemic cells display increased sensitivity to the YEATS inhibitor SGC-iMLLT compared to control AML cells. Our results demonstrate that the YEATS domain is important for MLL-ENL fusion protein-mediated leukemogenesis and exposes an "Achilles heel" that may be therapeutically targeted for treating t(11;19) patients.

DOI: https://doi.org/10.1038/s41375-022-01765-0
Cell Rep. 2022 Nov 29. pii: S2211-1247(22)01605-9. [Epub ahead of print]41(9): 111727

SETD1A regulates transcriptional pause release of heme biosynthesis genes in leukemia.

Takayuki Hoshii, Sarah Perlee, Sota Kikuchi, Bahityar Rahmutulla, Masaki Fukuyo, Takeshi Masuda, Sumio Ohtsuki, Tomoyoshi Soga, Behnam Nabet, Atsushi Kaneda.

  Histone methyltransferase SETD1A is critical for acute myeloid leukemia (AML) cell survival, but the molecular mechanism driving SETD1A gene regulation remains elusive. To delineate the role of SETD1A, we utilize a protein degrader technology to induce rapid SETD1A degradation in AML cell lines. SETD1A degradation results in immediate downregulation of transcripts associated with DNA repair and heme biosynthesis pathways. CRISPR-based functional analyses and metabolomics reveal an essential role of SETD1A to maintain mitochondrial respiration in AML cells. These SETD1A targets are enriched in head-to-head (H2H) genes. SETD1A degradation disrupts a non-enzymatic SETD1A domain-dependent cyclin K function, increases the Ser5P RNA polymerase II (RNAPII) at the transcriptional start site (TSS), and induces the promoter-proximal pausing of RNAPII in a strand-specific manner. This study reveals a non-enzymatic role for SETD1A in transcriptional pause release and provides insight into the mechanism of RNAPII pausing and its function in cancer.

Keywords:  CP: Molecular biology; SETD1A; cyclin K; elongation; heme biosynthesis; leukemia

DOI:  https://doi.org/10.1016/j.celrep.2022.111727
J Hematol Oncol. 2022 Dec 01. 15(1): 171

Electrostatic anti-CD33-antibody-protamine nanocarriers as platform for a targeted treatment of acute myeloid leukemia.

Nicole Bäumer, Annika Scheller, Lisa Wittmann, Andreas Faust, Mara Apel, Subbaiah Chary Nimmagadda, Christiane Geyer, Katharina Grunert, Neele Kellmann, Matthias Peipp, Sareetha Kailayangiri, Matias Ezequiel Gutierrez Suburu, Cristian A Strassert, Mathias Schenk, Lilo Greune, Christian Rüter, Petra Dersch, Wolfgang Hartmann, Claudia Rossig, Dario Neri, Carsten Müller-Tidow, Christian Schwöppe, Christoph Schliemann, Cyrus Khandanpour, Georg Lenz, Wolfgang E Berdel, Sebastian Bäumer.

   BACKGROUND: Acute myeloid leukemia (AML) is a fatal clonal hematopoietic malignancy, which results from the accumulation of several genetic aberrations in myeloid progenitor cells, with a worldwide 5-year survival prognosis of about 30%. Therefore, the development of more effective therapeutics with novel mode of action is urgently demanded. One common mutated gene in the AML is the DNA-methyltransferase DNMT3A whose function in the development and maintenance of AML is still unclear. To specifically target "undruggable" oncogenes, we initially invented an RNAi-based targeted therapy option that uses the internalization capacity of a colorectal cancer specific anti-EGFR-antibody bound to cationic protamine and the anionic siRNA. Here, we present a new experimental platform technology of molecular oncogene targeting in AML.
METHODS: Our AML-targeting system consists of an internalizing anti-CD33-antibody-protamine conjugate, which together with anionic molecules such as siRNA or ibrutinib-Cy3.5 and cationic free protamine spontaneously assembles into vesicular nanocarriers in aqueous solution. These nanocarriers were analyzed concerning their physical properties and relevant characteristics in vitro in cell lines and in vivo in xenograft tumor models and patient-derived xenograft leukemia models with the aim to prepare them for translation into clinical application.
RESULTS: The nanocarriers formed depend on a balanced electrostatic combination of the positively charged cationic protamine-conjugated anti-CD33 antibody, unbound cationic protamine and the anionic cargo. This nanocarrier transports its cargo safely into the AML target cells and has therapeutic activity against AML in vitro and in vivo. siRNAs directed specifically against two common mutated genes in the AML, the DNA-methyltransferase DNMT3A and FLT3-ITD lead to a reduction of clonal growth in vitro in AML cell lines and inhibit tumor growth in vivo in xenotransplanted cell lines. Moreover, oncogene knockdown of DNMT3A leads to increased survival of mice carrying leukemia patient-derived xenografts. Furthermore, an anionic derivative of the approved Bruton's kinase (BTK) inhibitor ibrutinib, ibrutinib-Cy3.5, is also transported by this nanocarrier into AML cells and decreases colony formation.
CONCLUSIONS: We report important results toward innovative personalized, targeted treatment options via electrostatic nanocarrier therapy in AML.

Keywords:  DNMT3A inhibition; Gemtuzumab; Ibrutinib; Molecular targeted therapy; RNA interference

DOI:  https://doi.org/10.1186/s13045-022-01390-5
Bone Marrow Transplant. 2022 Dec 02.

Total body irradiation plus fludarabine versus busulfan plus fludarabine as a myeloablative conditioning for adults with acute myeloid leukemia treated with allogeneic hematopoietic cell transplantation. A study on behalf of the Acute Leukemia Working Party of the EBMT.

Ryszard Swoboda, Myriam Labopin, Sebastian Giebel, Thomas Schroeder, Nicolaus Kröger, Mutlu Arat, Bipin Savani, Alexandros Spyridonidis, Rose-Marie Hamladji, Victoria Potter, Ana Berceanu, Ibrahim Yakoub-Agha, Alessandro Rambaldi, Hakan Ozdogu, Jaime Sanz, Arnon Nagler, Mohamad Mohty.

Cyclophosphamide is frequently substituted with fludarabine (Flu) in conditioning regimens before allogeneic hematopoietic cell transplantation (allo-HCT). We aimed to compare retrospectively, total body irradiation (12 Gy) plus Flu (FluTBI12) versus busulfan (Bu) plus Flu (FB4) as a myeloablative conditioning before allo-HCT in patients with acute myeloid leukemia (AML). Out of 3203 patients who met the inclusion criteria, 109 patients treated with FluTBI12 and 213 treated with FB4 were included in a final matched-pair analysis. In both groups, median patient age was 41 years, first or second complete remission (CR1/CR2) proportion was 78%/22%, allo-HCT from an unrelated donor was performed in 78% of patients. The probabilities of leukemia-free survival and overall survival at 2 years in FluTBI12 and FB4 groups were 65% vs. 60% (p = 0.64) and 70% vs. 72% (p = 0.87), respectively. The cumulative incidence of relapse was 19% vs. 29% (p = 0.11), while non-relapse mortality was 16% vs. 11%, respectively (p = 0.13). There were no statistical differences in both acute and chronic graft-versus-host disease (GVHD) incidence. The probability of GVHD-free, relapse-free survival (GRFS) was 49% for both groups. FluTBI12 and FB4 are comparable myeloablative regimens before allo-HCT in AML patients transplanted in CR1 and CR2.

DOI: https://doi.org/10.1038/s41409-022-01882-5
Front Oncol. 2022 ;12 1017947

Disrupting PTPRJ transmembrane-mediated oligomerization counteracts oncogenic receptor tyrosine kinase FLT3 ITD.

Marie Schwarz, Sophie Rizzo, Walter Espinoza Paz, Anne Kresinsky, Damien Thévenin, Jörg P Müller.

  The receptor protein tyrosine phosphatase (RPTP) PTPRJ (also known as DEP-1) has been identified as a negative regulator of the receptor tyrosine kinase FLT3 signalling in vitro. The inactivation of the PTPRJ gene in mice expressing the constitutively active, oncogenic receptor tyrosine kinase FLT3 ITD aggravated known features of leukaemogenesis, revealing PTPRJ's antagonistic role. FLT3 ITD mutations resulting in constitutively kinase activity and cell transformation frequently occur in patients with acute myeloid leukaemia (AML). Thus, in situ activation of PTPRJ could be used to abrogate oncogenic FLT3 signalling. The activity of PTPRJ is suppressed by homodimerization, which is mediated by transmembrane domain (TMD) interactions. Specific Glycine-to-Leucine mutations in the TMD disrupt oligomerization and inhibit the Epidermal Growth Factor Receptor (EGFR) and EGFR-driven cancer cell phenotypes. To study the effects of PTPRJ TMD mutant proteins on FLT3 ITD activity in cell lines, endogenous PTPRJ was inactivated and replaced by stable expression of PTPRJ TMD mutants. Autophosphorylation of wild-type and ITD-mutated FLT3 was diminished in AML cell lines expressing the PTPRJ TMD mutants compared to wild-type-expressing cells. This was accompanied by reduced FLT3-mediated global protein tyrosine phosphorylation and downstream signalling. Further, PTPRJ TMD mutant proteins impaired the proliferation and in vitro transformation of leukemic cells. Although PTPRJ's TMD mutant proteins showed impaired self-association, the specific phosphatase activity of immunoprecipitated proteins remained unchanged. In conclusion, this study demonstrates that the destabilization of PTPRJ TMD-mediated self-association increases the activity of PTPRJ in situ and impairs FLT3 activity and FLT3-driven cell phenotypes of AML cells. Thus, disrupting the oligomerization of PTPRJ in situ could prove a valuable therapeutic strategy to restrict oncogenic FLT3 activity in leukemic cells.

Keywords:  AML; DEP-1; oncogenic FLT3 ITD; receptor protein tyrosine phosphatase (RPTP); receptor tyrosine kinase (RTK); signal transduction; transmembrane domain oligomerization

DOI:  https://doi.org/10.3389/fonc.2022.1017947
BMC Cancer. 2022 Dec 02. 22(1): 1254

Targeting integrated stress response with ISRIB combined with imatinib treatment attenuates RAS/RAF/MAPK and STAT5 signaling and eradicates chronic myeloid leukemia cells.

Wioleta Dudka, Grazyna Hoser, Shamba S Mondal, Laura Turos-Korgul, Julian Swatler, Monika Kusio-Kobialka, Magdalena Wołczyk, Agata Klejman, Marta Brewinska-Olchowik, Agata Kominek, Milena Wiech, Marcin M Machnicki, Ilona Seferynska, Tomasz Stoklosa, Katarzyna Piwocka.

  The integrated stress response (ISR) facilitates cellular adaptation to unfavorable conditions by reprogramming the cellular response. ISR activation was reported in neurological disorders and solid tumors; however, the function of ISR and its role as a possible therapeutic target in hematological malignancies still remain largely unexplored. Previously, we showed that the ISR is activated in chronic myeloid leukemia (CML) cells and correlates with blastic transformation and tyrosine kinase inhibitor (TKI) resistance. Moreover, the ISR was additionally activated in response to imatinib as a type of protective internal signaling. Here, we show that ISR inhibition combined with imatinib treatment sensitized and more effectively eradicated leukemic cells both in vitro and in vivo compared to treatment with single agents. The combined treatment specifically inhibited the STAT5 and RAS/RAF/MEK/ERK pathways, which are recognized as drivers of resistance. Mechanistically, this drug combination attenuated both interacting signaling networks, leading to BCR-ABL1- and ISR-dependent STAT5 activation. Consequently, leukemia engraftment in patient-derived xenograft mice bearing CD34+ TKI-resistant CML blasts carrying PTPN11 mutation responsible for hyperactivation of the RAS/RAF/MAPK and JAK/STAT5 pathways was decreased upon double treatment. This correlated with the downregulation of genes related to the RAS/RAF/MAPK, JAK/STAT5 and stress response pathways and was associated with lower expression of STAT5-target genes regulating proliferation, viability and the stress response. Collectively, these findings highlight the effect of imatinib plus ISRIB in the eradication of leukemic cells resistant to TKIs and suggest potential clinical benefits for leukemia patients with TKI resistance related to RAS/RAF/MAPK or STAT5 signaling. We propose that personalized treatment based on the genetic selection of patients carrying mutations that cause overactivation of the targeted pathways and therefore make their sensitivity to such treatment probable should be considered as a possible future direction in leukemia treatment.

Keywords:  CML; ISR; ISRIB; Myeloid leukemia; PTPN11; RAS/RAF/MAPK; STAT5; TKI resistance

DOI:  https://doi.org/10.1186/s12885-022-10289-w
Br J Haematol. 2022 Nov 28.

Treatment response in acute myeloid leukaemia-Clues in the biopsy core.

Alicia G Aguilar Navarro, Anastasia N Tikhonova.

  In their paper the authors describe distinct transcriptomic changes associated to treatment response in core bone marrow biopsies from patients with acute myeloid leukaemia. This finding raises the possibility that stratifying patients for treatment according to their transcriptomic profiles could improve patients' response and prognosis. Commentary on: Treaba et al. Transcriptomics of AML core bone marrow biopsies reveals distinct therapy response-specific osteo-mesenchymal profiles. Br J Haematol 2022 (Online ahead of print). doi: 10.1111/bjh.18513.

Keywords:  acute myeloid leukaemia; bone marrow; microenvironment

DOI:  https://doi.org/10.1111/bjh.18579
Blood. 2022 Nov 28. pii: blood.2022017661. [Epub ahead of print]

Associations of clonal haematopoiesis with recurrent vascular events and death in patients with incident ischemic stroke.

Christopher Maximilian Arends, Thomas G Liman, Paulina M Strzelecka, Anna Kufner, Pelle Löwe, Shufan Huo, Catarina M Stein, Sophie K Piper, Marlon Tilgner, Pia S Sperber, Savvina Dimitriou, Peter Heuschmann, Raphael Hablesreiter, Christoph Harms, Lars Bullinger, Joachim E Weber, Matthias Endres, Frederik Damm.

Clonal hematopoiesis (CH) is common among older people and associated with an increased risk of atherosclerosis, inflammation, and shorter overall survival. Age and inflammation are major risk factors for ischemic stroke, yet the association of CH with risk of secondary vascular events and death is unknown. We investigated CH in peripheral blood DNA from 581 patients with first-ever ischemic stroke from the Prospective Cohort with Incident Stroke-Berlin study (PROSCIS-B) using error-corrected targeted sequencing. The primary composite endpoint (CEP) consisted of recurrent stroke, myocardial infarction, and all-cause mortality. 348 somatic mutations with a variant allele frequency ≥ 1% were identified in 236/581 patients (41%). CH was associated with large-artery atherosclerosis stroke (P = 0.01) and white matter lesion (P < 0.001). CH-positive patients showed increased levels of pro-inflammatory cytokines such as IL-6, IFN-γ, hsCRP, and VCAM-1. CH-positive patients had a higher risk for the primary CEP (HR: 1.55, 95%-CI 1.04 - 2.31, P = 0.03), which was more pronounced in patients with larger clones. CH clone size remained an independent risk factor (HR 1.30, 95%-CI 1.04 - 1.62, P = 0.022) in multivariable Cox regression. While our data show that in particular larger and TET2- or PPM1D-mutated clones are associated with increased risk of recurrent vascular events and death, this risk is partially mitigated by a common germline variant of the IL-6 receptor (IL-6R p.D358A). The CH mutation profile is accompanied by a pro-inflammatory profile opening new avenues for preventive precision medicine approaches to resolve the self-perpetuating cycle of inflammation and clonal expansion.

DOI: https://doi.org/10.1182/blood.2022017661
Leuk Res. 2022 Nov 25. pii: S0145-2126(22)00371-X. [Epub ahead of print]124 106995

Distinct mutational and clinicopathologic profiles characterize acute myeloid leukemia with cup-like nuclei.

Estelle Oertling, Franklin Fuda, Prasad Koduru, Mingyi Chen, Olga Weinberg, Marisa Juntilla, Jesse Jaso, Madhuri Vusirikala, Stephen Chung, Praveen Ramakrishnan Geethakumari, Yazan F Madanat, Robert Collins, Jeffrey Gagan, Weina Chen.



Keywords:  Acute myeloid leukemia; Cuplike nuclei; FLT3; IDH; Immunophenotype; NPM1; TET2

DOI:  https://doi.org/10.1016/j.leukres.2022.106995
Leukemia. 2022 Dec 02.

Transient regulation of RNA methylation in human hematopoietic stem cells promotes their homing and engraftment.

Xuepeng Wang, Scott Cooper, Hal E Broxmeyer, Reuben Kapur.

Enhancing the efficiency of hematopoietic stem cell (HSC) homing and engraftment is critical for cord blood (CB) hematopoietic cell transplantation (HCT). Recent studies indicate that N6-methyladenosine (m6A) modulates the expression of mRNAs that are critical for stem cell function by influencing their stability. Here, we demonstrate that inhibition of RNA decay by regulation of RNA methylation, enhances the expression of the homing receptor chemokine C-X-C receptor-4 (CXCR4) in HSCs. We show that YTH N6-methyladenosine RNA binding protein 2 (YTHDF2), a m6A reader and FTO α-ketoglutarate dependent dioxygenase (FTO), a m6A eraser play an opposite role in this process. Through screening, we identified several FDA-approved compounds that regulate the expression of YTHDF2 and FTO in CB CD34+ cells. We show that transient downregulation of YTHDF2 or activation of FTO by using these compounds inhibits CXCR4 decay in CB HSCs and promotes their homing and engraftment. Our results demonstrate a novel regulation strategy to enhance the function of CB HSCs and provide a translational approach to enhance the clinical efficacy of HCT.

DOI: https://doi.org/10.1038/s41375-022-01761-4
Nat Commun. 2022 Nov 28. 13(1): 7159

PCGF1-PRC1 links chromatin repression with DNA replication during hematopoietic cell lineage commitment.

Junichiro Takano, Shinsuke Ito, Yixing Dong, Jafar Sharif, Yaeko Nakajima-Takagi, Taichi Umeyama, Yong-Woon Han, Kyoichi Isono, Takashi Kondo, Yusuke Iizuka, Tomohiro Miyai, Yoko Koseki, Mika Ikegaya, Mizuki Sakihara, Manabu Nakayama, Osamu Ohara, Yoshinori Hasegawa, Kosuke Hashimoto, Erik Arner, Robert J Klose, Atsushi Iwama, Haruhiko Koseki, Tomokatsu Ikawa.

Polycomb group proteins (PcG), polycomb repressive complexes 1 and 2 (PRC1 and 2), repress lineage inappropriate genes during development to maintain proper cellular identities. It has been recognized that PRC1 localizes at the replication fork, however, the precise functions of PRC1 during DNA replication are elusive. Here, we reveal that a variant PRC1 containing PCGF1 (PCGF1-PRC1) prevents overloading of activators and chromatin remodeling factors on nascent DNA and thereby mediates proper deposition of nucleosomes and correct downstream chromatin configurations in hematopoietic stem and progenitor cells (HSPCs). This function of PCGF1-PRC1 in turn facilitates PRC2-mediated repression of target genes such as Hmga2 and restricts premature myeloid differentiation. PCGF1-PRC1, therefore, maintains the differentiation potential of HSPCs by linking proper nucleosome configuration at the replication fork with PcG-mediated gene silencing to ensure life-long hematopoiesis.

DOI: https://doi.org/10.1038/s41467-022-34856-8
Blood. 2022 Nov 30. pii: blood.2022017249. [Epub ahead of print]

Somatic TP53 mutations are pre-leukemic events in acute lymphoblastic leukemia.

Guranda Chitadze, Anna Stengel, Cathrin John-Klaua, Julien Bruckmüller, Heiko Trautmann, Michaela Kotrova, Franziska Darzentas, Miriam Kelm, Karol Pal, Nikos Darzentas, Lorenz Bastian, Britta Kehden, Wiebke Wessels, Aeint-Steffen Ströh, Hans-Heinrich Oberg, Philipp M Altrock, Constance Baer, Manja Meggendorfer, Claudia Haferlach, Nicola Goekbuget, Claudia D Baldus, Monika Brüggemann.

DOI: https://doi.org/10.1182/blood.2022017249
Nature. 2022 Nov 30.

Genomic signature of Fanconi anaemia DNA repair pathway deficiency in cancer.

Andrew L H Webster, Mathijs A Sanders, Krupa Patel, Ralf Dietrich, Raymond J Noonan, Francis P Lach, Ryan R White, Audrey Goldfarb, Kevin Hadi, Matthew M Edwards, Frank X Donovan, Remco M Hoogenboezem, Moonjung Jung, Sunandini Sridhar, Tom F Wiley, Olivier Fedrigo, Huasong Tian, Joel Rosiene, Thomas Heineman, Jennifer A Kennedy, Lorenzo Bean, Rasim O Rosti, Rebecca Tryon, Ashlyn-Maree Gonzalez, Allana Rosenberg, Ji-Dung Luo, Thomas S Carroll, Sanjana Shroff, Michael Beaumont, Eunike Velleuer, Jeff C Rastatter, Susanne I Wells, Jordi Surrallés, Grover Bagby, Margaret L MacMillan, John E Wagner, Maria Cancio, Farid Boulad, Theresa Scognamiglio, Roger Vaughan, Kristin G Beaumont, Amnon Koren, Marcin Imielinski, Settara C Chandrasekharappa, Arleen D Auerbach, Bhuvanesh Singh, David I Kutler, Peter J Campbell, Agata Smogorzewska.

Fanconi anaemia (FA), a model syndrome of genome instability, is caused by a deficiency in DNA interstrand crosslink repair resulting in chromosome breakage1-3. The FA repair pathway protects against endogenous and exogenous carcinogenic aldehydes4-7. Individuals with FA are hundreds to thousands fold more likely to develop head and neck (HNSCC), oesophageal and anogenital squamous cell carcinomas8 (SCCs). Molecular studies of SCCs from individuals with FA (FA SCCs) are limited, and it is unclear how FA SCCs relate to sporadic HNSCCs primarily driven by tobacco and alcohol exposure or infection with human papillomavirus9 (HPV). Here, by sequencing genomes and exomes of FA SCCs, we demonstrate that the primary genomic signature of FA repair deficiency is the presence of high numbers of structural variants. Structural variants are enriched for small deletions, unbalanced translocations and fold-back inversions, and are often connected, thereby forming complex rearrangements. They arise in the context of TP53 loss, but not in the context of HPV infection, and lead to somatic copy-number alterations of HNSCC driver genes. We further show that FA pathway deficiency may lead to epithelial-to-mesenchymal transition and enhanced keratinocyte-intrinsic inflammatory signalling, which would contribute to the aggressive nature of FA SCCs. We propose that the genomic instability in sporadic HPV-negative HNSCC may arise as a result of the FA repair pathway being overwhelmed by DNA interstrand crosslink damage caused by alcohol and tobacco-derived aldehydes, making FA SCC a powerful model to study tumorigenesis resulting from DNA-crosslinking damage.

DOI: https://doi.org/10.1038/s41586-022-05253-4
Annu Rev Med. 2022 Nov 30.

Clonal Hematopoiesis and Its Impact on Human Health.

Herra Ahmad, Nikolaus Jahn, Siddhartha Jaiswal.

Aging is associated with increased mutational burden in every tissue studied. Occasionally, fitness-increasing mutations will arise, leading to stem cell clonal expansion. This process occurs in several tissues but has been best studied in blood. Clonal hematopoiesis is associated with an increased risk of blood cancers, such as acute myeloid leukemia, which result if additional cooperating mutations occur. Surprisingly, it is also associated with an increased risk of nonmalignant diseases, such as atherosclerotic cardiovascular disease. This may be due to enhanced inflammation in mutated innate immune cells, which could be targeted clinically with anti-inflammatory drugs. Recent studies have uncovered other factors that predict poor outcomes in patients with clonal hematopoiesis, such as size of the mutant clone, mutated driver genes, and epigenetic aging. Though clonality is inevitable and largely a function of time, recent work has shown that inherited genetic variation can also influence this process. Clonal hematopoiesis provides a paradigm for understanding how age-related changes in tissue stem cell composition and function influence human health. Expected final online publication date for the Annual Review of Medicine, Volume 74 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

DOI: https://doi.org/10.1146/annurev-med-042921-112347
Nature. 2022 Nov 30.

Ras drives malignancy through stem cell crosstalk with the microenvironment.

Shaopeng Yuan, Katherine S Stewart, Yihao Yang, Merve Deniz Abdusselamoglu, S Martina Parigi, Tamar Y Feinberg, Karen Tumaneng, Hanseul Yang, John M Levorse, Lisa Polak, David Ng, Elaine Fuchs.

Squamous cell carcinomas are triggered by marked elevation of RAS-MAPK signalling and progression from benign papilloma to invasive malignancy1-4. At tumour-stromal interfaces, a subset of tumour-initiating progenitors, the cancer stem cells, obtain increased resistance to chemotherapy and immunotherapy along this pathway5,6. The distribution and changes in cancer stem cells during progression from a benign state to invasive squamous cell carcinoma remain unclear. Here we show in mice that, after oncogenic RAS activation, cancer stem cells rewire their gene expression program and trigger self-propelling, aberrant signalling crosstalk with their tissue microenvironment that drives their malignant progression. The non-genetic, dynamic cascade of intercellular exchanges involves downstream pathways that are often mutated in advanced metastatic squamous cell carcinomas with high mutational burden7. Coupling our clonal skin HRASG12V mouse model with single-cell transcriptomics, chromatin landscaping, lentiviral reporters and lineage tracing, we show that aberrant crosstalk between cancer stem cells and their microenvironment triggers angiogenesis and TGFβ signalling, creating conditions that are conducive for hijacking leptin and leptin receptor signalling, which in turn launches downstream phosphoinositide 3-kinase (PI3K)-AKT-mTOR signalling during the benign-to-malignant transition. By functionally examining each step in this pathway, we reveal how dynamic temporal crosstalk with the microenvironment orchestrated by the stem cells profoundly fuels this path to malignancy. These insights suggest broad implications for cancer therapeutics.

DOI: https://doi.org/10.1038/s41586-022-05475-6
Blood Rev. 2022 Nov 11. pii: S0268-960X(22)00105-9. [Epub ahead of print] 101031

Haploidentical bone marrow transplants with post transplant cyclophosphamide on day + 3 + 5: The Genova protocol.

Anna Maria Raiola, Emanuele Angelucci, Simona Sica, Andrea Bacigalupo.

  We report 634 patients who underwent unmanipulated haploidentical (HAPLO) bone marrow transplantation (BMT) in two Centers. The diagnosis was acute myeloid leukemia (AML) (n = 251), acute lymphoblastic leukemia (ALL)(n = 107), myelodysplastic syndrome and myelofibrosis (MDS + MF) (n = 125) and chronic lymphoproliferative disorders (n = 151). Median age was 52 years (16-74). Graft versus host disease (GvHD) prophylaxis was intravenous cyclosporin (CSA) starting on day 0, oral mycophenolate on day +1, and post-transplant cyclophosphamide (PTCY) on days +3 + 5. Primary graft failure was seen in 23 patients (3,6%); 17 /23 (74%) were rescued with second HAPLO graft, and were alive at one year. The cumulative incidence of acute GvHD grade II-IV was 29% and 3% for grade III-IV; the cumulative incidence of moderate severe chronic GvHD was 23%: older donor and patients age were significant predictors of both acute and chronic GvHD. The overall non relapse mortality (NRM) at 2 years was 19%: 8%, 21% and 30% in patients aged <40, 41-60 > 60 years. Disease free survival (DFS) at 5 years was 64% for acute leukemia in first remission, 51% for acute leukemia CR2, 25% for acute leukemia advanced disease and 49% for MDS/MPN. We confirm, on a relatively large number of patients, that unmanipulated HAPLO BMT with PTCY on days +3 + 5, mostly after a myeloablative conditioning regimen, is followed by a low incidence of graft failure and grade III-IV GvHD; moderate severe chronic GvHD is 23% and NRM at 2 years 19%; 5 year DFS is influenced by remission status of the underlying disease.

Keywords:  Cyclophosphamide; GVHD; Haploidentical; Myeloablative

DOI:  https://doi.org/10.1016/j.blre.2022.101031
BMC Cancer. 2022 Nov 29. 22(1): 1229

Comprehensive analysis of ID genes reveals the clinical and prognostic value of ID3 expression in acute myeloid leukemia using bioinformatics identification and experimental validation.

Qi Zhao, Yun Wang, Di Yu, Jia-Yan Leng, Yangjing Zhao, Mingqiang Chu, Zijun Xu, Hao Ding, Jingdong Zhou, Tingjuan Zhang.

   BACKGROUND: Dysregulation of inhibitor of differentiation/DNA binding (ID) genes is linked to cancer growth, angiogenesis, invasiveness, metastasis and patient survival. Nevertheless, few investigations have systematically determined the expression and prognostic value of ID genes in acute myeloid leukemia (AML).
METHODS: The expression and clinical prognostic value of ID genes in AML were first identified by public databases and further validated by our research cohort.
RESULTS: Using public data, the expression of ID1/ID3 was markedly downregulated in AML, and the expression of ID2 was greatly upregulated in AML, whereas ID4 showed no significant difference. Among the ID genes, only ID3 expression may be the most valuable prognostic biomarker in both total AML and cytogenetically normal AML (CN-AML) and especially in CN-AML. Clinically, reduced ID3 expression was greatly associated with higher white blood cell counts, peripheral blood/bone marrow blasts, normal karyotypes and intermediate cytogenetic risk. In addition, low ID3 expression was markedly related to FLT3 and NPM1 mutations as well as wild-type TP53. Despite these associations, multivariate Cox regression analysis revealed that ID3 expression was an independent risk factor affecting overall survival (OS) and disease free survival (DFS) in CN-AML patients. Biologically, a total of 839 mRNAs/lncRNAs and 72 microRNAs were found to be associated with ID3 expression in AML. Importantly, the expression of ID3 with discriminative value in AML was further confirmed in our research cohort.
CONCLUSION: The bioinformatics analysis and experimental verification demonstrate that low ID3 expression independently affects OS and DFS in patients with CN-AML, which might be seen as a potential prognostic indicator in CN-AML.

Keywords:  AML; Expression; ID; ID3; Prognosis

DOI:  https://doi.org/10.1186/s12885-022-10352-6
Blood. 2022 Dec 01. pii: blood.2022017715. [Epub ahead of print]

DDX41-associated susceptibility to myeloid neoplasms.

Hideki Makishima, Teresa Venezia Bowman, Lucy A Godley.

Deleterious germline DDX41 variants confer risk for myeloid neoplasms (MNs), and less frequently to lymphoid malignancies, with autosomal dominant inheritance and an estimated prevalence of 3% among MNs. Germline DDX41 variants include truncating alleles that comprise about two thirds of all alleles; missense variants located preferentially within the DEAD box domain; and deletion variants. The identification of a truncating allele on tumor-based molecular profiling should prompt germline genetic testing, since virtually all such alleles are germline. Somatic mutation of the wild-type DDX41 allele occurs in about half of MNs with germline DDX41 alleles, typically in exons encoding the helicase domain and most frequently as R525H. Several aspects of deleterious germline DDX41 alleles are noteworthy: (i) Certain variants are common in particular populations; (ii) MNs develop at older ages typical of de novo disease, challenging the paradigm that inherited cancer risk always causes disease in young people; (iii) Despite equal frequencies of these variants in men and women, men progress to MNs more frequently, suggesting a gender-specific effect on myeloid leukemogenesis; and (iv) Individuals with deleterious germline DDX41 variants develop acute severe graft versus host disease after allogeneic hematopoietic cell transplantation with wild-type donors more than others unless they receive post-transplant cyclophosphamide, suggesting a pro-inflammatory milieu that stimulates donor-derived T-cells. Biochemical studies and animal models have identified DDX41's ability to interact with double stranded DNA and RNA:DNA hybrids with roles in mRNA splicing, rRNAs/snoRNAs processing, and modulation of innate immunity, disruption of which could promote inflammation and drive tumorigenesis.

DOI: https://doi.org/10.1182/blood.2022017715
Blood Adv. 2022 Dec 01. pii: bloodadvances.2022009038. [Epub ahead of print]

Cord blood transplantation for nonmalignant disorders: early functional immunity and high survival.

Caridad Martinez, Paibel Aguayo-Hiraldo, Natalia Chimowitz, Lisa Forbes, Nicholas L Rider, Sarah Nicholas, Filiz Seeborg, Javier Chinen, Ivan K Chinn, Carla Davis, Howard M Rosenblatt, Lenora M Noroski, Bilal Omer, Tami D John, Khaled Yassine, Swati Naik, John Craddock, Saleh Bhar, Carl Allen, Nabil Ahmed, Ghadir Sasa, David Steffin, Erin E Doherty, Anil George, Baheyeldin Salem, Brian D Friend, Meenakshi Hegde, Malcolm K Brenner, Helen E Heslop, Ann Leen, Amanda Michelle Peña, Mengfen Wu, Celine Hanson, Robert A Krance.

There is no consensus about the best donor for children with non-malignant disorders and immune deficiencies in the absence of a matched related donor (MRD). We now evaluate the 2-year Overall Survival after Umbilical Cord Blood Transplantation (UCBT) in patients with non-malignant disorders from 2009-2020 enrolled on a prospective clinical trial using either 5/6 or 6/6 umbilical cord blood as cell source. Patients receive a fully ablative busulfan, cyclophosphamide, and fludarabine without serotherapy. 55 children were enrolled, median age 5 mo. (range, 1-111 mo.); PID (45), metabolic (5), HLH (1), and hematologic disorders (4). Twenty-six patients had persistent infections prior to transplant. 19 (34%) were 6/6 matched, 36 (66%) were 5/6 HLA matched. The overall survival (OS) at 2 years was 91% (95% CI:79-96%) with a median follow up of 4.3 years. The median time to neutrophil and platelet recovery were 17 days (range,5-39 days) and 37 days (range,20-92 days), respectively. All but one evaluable patient achieved full donor chimerism. The cumulative incidence of aGvHD grade II-IV by day 100 was 16% (n=9). All patients with viral infections at the time of transplant cleared the infection at a median time of 54 days (range, 44-91 days). All evaluable patients have had correction of their immune or metabolic defect. We conclude that in the absence of a MRD, UCBT following myeloablative conditioning without serotherapy is an excellent curative option in young children with non-malignant disorders. This trial is registered at www.clinicaltrials.gov as NCT00950846.

DOI: https://doi.org/10.1182/bloodadvances.2022009038
Lancet Haematol. 2022 Nov 24. pii: S2352-3026(22)00323-4. [Epub ahead of print]

A sex-informed approach to improve the personalised decision making process in myelodysplastic syndromes: a multicentre, observational cohort study.

GenoMed4All consortium

BACKGROUND: Sex is a major source of diversity among patients and a sex-informed approach is becoming a new paradigm in precision medicine. We aimed to describe sex diversity in myelodysplastic syndromes in terms of disease genotype, phenotype, and clinical outcome. Moreover, we sought to incorporate sex information into the clinical decision-making process as a fundamental component of patient individuality.
METHODS: In this multicentre, observational cohort study, we retrospectively analysed 13 284 patients aged 18 years or older with a diagnosis of myelodysplastic syndrome according to 2016 WHO criteria included in the EuroMDS network (n=2025), International Working Group for Prognosis in MDS (IWG-PM; n=2387), the Spanish Group of Myelodysplastic Syndromes registry (GESMD; n=7687), or the Düsseldorf MDS registry (n=1185). Recruitment periods for these cohorts were between 1990 and 2016. The correlation between sex and genomic features was analysed in the EuroMDS cohort and validated in the IWG-PM cohort. The effect of sex on clinical outcome, with overall survival as the main endpoint, was analysed in the EuroMDS population and validated in the other three cohorts. Finally, novel prognostic models incorporating sex and genomic information were built and validated, and compared to the widely used revised International Prognostic Scoring System (IPSS-R). This study is registered with ClinicalTrials.gov, NCT04889729.
FINDINGS: The study included 7792 (58·7%) men and 5492 (41·3%) women. 10 906 (82·1%) patients were White, and race was not reported for 2378 (17·9%) patients. Sex biases were observed at the single-gene level with mutations in seven genes enriched in men (ASXL1, SRSF2, and ZRSR2 p<0·0001 in both cohorts; DDX41 not available in the EuroMDS cohort vs p=0·0062 in the IWG-PM cohort; IDH2 p<0·0001 in EuroMDS vs p=0·042 in IWG-PM; TET2 p=0·031 vs p=0·035; U2AF1 p=0·033 vs p<0·0001) and mutations in two genes were enriched in women (DNMT3A p<0·0001 in EuroMDS vs p=0·011 in IWG-PM; TP53 p=0·030 vs p=0·037). Additionally, sex biases were observed in co-mutational pathways of founding genomic lesions (splicing-related genes, predominantly in men, p<0·0001 in both the EuroMDS and IWG-PM cohorts), in DNA methylation (predominantly in men, p=0·046 in EuroMDS vs p<0·0001 in IWG-PM), and TP53 mutational pathways (predominantly in women, p=0·0073 in EuroMDS vs p<0·0001 in IWG-PM). In the retrospective EuroMDS cohort, men had worse median overall survival (81·3 months, 95% CI 70·4-95·0 in men vs 123·5 months, 104·5-127·5 in women; hazard ratio [HR] 1·40, 95% CI 1·26-1·52; p<0·0001). This result was confirmed in the prospective validation cohorts (median overall survival was 54·7 months, 95% CI 52·4-59·1 in men vs 74·4 months, 69·3-81·2 in women; HR 1·30, 95% CI 1·23-1·35; p<0·0001 in the GEMSD MDS registry; 40·0 months, 95% CI 33·4-43·7 in men vs 54·2 months, 38·6-63·8 in women; HR 1·23, 95% CI 1·08-1·36; p<0·0001 in the Dusseldorf MDS registry). We developed new personalised prognostic tools that included sex information (the sex-informed prognostic scoring system and the sex-informed genomic scoring system). Sex maintained independent prognostic power in all prognostic systems; the highest performance was observed in the model that included both sex and genomic information. A five-to-five mapping between the IPSS-R and new score categories resulted in the re-stratification of 871 (43·0%) of 2025 patients from the EuroMDS cohort and 1003 (42·0%) of 2387 patients from the IWG-PM cohort by using the sex-informed prognostic scoring system, and of 1134 (56·0%) patients from the EuroMDS cohort and 1265 (53·0%) patients from the IWG-PM cohort by using the sex-informed genomic scoring system. We created a web portal that enables outcome predictions based on a sex-informed personalised approach.
INTERPRETATION: Our results suggest that a sex-informed approach can improve the personalised decision making process in patients with myelodysplastic syndromes and should be considered in the design of clinical trials including low-risk patients.
FUNDING: European Union (Horizon 2020 and Transcan programs), Italian Association for Cancer Research, Italian Ministry of Health, and Italian Ministry of University and Research.

DOI: https://doi.org/10.1016/S2352-3026(22)00323-4
Cell Signal. 2022 Nov 25. pii: S0898-6568(22)00299-6. [Epub ahead of print] 110537

The indispensable role of the RNA helicase DDX5 in tumorigenesis induced by the myeloproliferative neoplasm-associated JAK2V617F mutant.

Kengo Takeda, Kenji Tago, Megumi Funakoshi-Tago.

  A point mutation (V617F) in the Janus kinase 2 (JAK2) gene results in the production of disorderly activated tyrosine kinase, which causes myeloproliferative neoplasms (MPN). We herein demonstrated that the RNA helicase DDX5 was highly expressed at the mRNA and protein levels through the activation of signal transducer and activator of transcription 5 (STAT5) in Ba/F3 cells expressing a JAK2V617F mutant and erythropoietin receptor (V617F/EpoR cells) and MPN patient-derived HEL cells. A treatment with the JAK1/2 inhibitor, ruxolitinib and STAT5 inhibitor, pimozide significantly inhibited DDX5 mRNA expression and enhanced the degradation of DDX5 in these cells, suggesting that the JAK2V617F mutant positively regulates DDX5 mRNA expression and DDX5 protein stability by activating STAT5. The knockdown of DDX5 specifically inhibited the activation of mechanistic target of rapamycin (mTOR) in V617F/EpoR cells and HEL cells and significantly suppressed the proliferation of these cells. Furthermore, the knockdown of DDX5 markedly suppressed tumorigenesis, splenomegaly, and liver hypertrophy caused by an inoculation of V617F/EpoR cells in nude mice. Collectively, these results revealed that JAK2V617F exhibits transforming activity by inducing the expression of DDX5 in a STAT5-dependent manner, indicating the potential of the JAK2V617F/STAT5/DDX5 axis as a therapeutic target in the treatment of MPN.

Keywords:  DDX5; JAK2 V617F mutant; Myeloproliferative neoplasms; STAT5; mTOR

DOI:  https://doi.org/10.1016/j.cellsig.2022.110537
Cancer Discov. 2022 Dec 02. 12(12): 2954

Correction: TP53-Mutated Myelodysplastic Syndrome and Acute Myeloid Leukemia: Biology, Current Therapy, and Future Directions.

DOI: https://doi.org/10.1158/2159-8290.CD-22-1192
Nat Commun. 2022 Dec 01. 13(1): 7400

PPM1D suppresses p53-dependent transactivation and cell death by inhibiting the Integrated Stress Response.

Zdenek Andrysik, Kelly D Sullivan, Jeffrey S Kieft, Joaquin M Espinosa.

The p53 transcription factor is a master regulator of cellular stress responses inhibited by repressors such as MDM2 and the phosphatase PPM1D. Activation of p53 with pharmacological inhibitors of its repressors is being tested in clinical trials for cancer therapy, but efficacy has been limited by poor induction of tumor cell death. We demonstrate that dual inhibition of MDM2 and PPM1D induces apoptosis in multiple cancer cell types via amplification of the p53 transcriptional program through the eIF2α-ATF4 pathway. PPM1D inhibition induces phosphorylation of eIF2α, ATF4 accumulation, and ATF4-dependent enhancement of p53-dependent transactivation upon MDM2 inhibition. Dual inhibition of p53 repressors depletes heme and induces HRI-dependent eIF2α phosphorylation. Pharmacological induction of eIF2α phosphorylation synergizes with MDM2 inhibition to induce cell death and halt tumor growth in mice. These results demonstrate that PPM1D inhibits both the p53 network and the integrated stress response controlled by eIF2α-ATF4, with clear therapeutic implications.

DOI: https://doi.org/10.1038/s41467-022-35089-5