bims-tremyl 2022-05-08 papers

on Therapy resistance biology in myeloid leukemia

Issue of 2022‒05‒08
thirty-two papers selected by
Paolo Gallipoli
Barts Cancer Institute, Queen Mary University of London

Inhibition of pyrimidine biosynthesis targets protein translation in acute myeloid leukemia.
Treatment-free remission after ceasing venetoclax-based therapy in patients with acute myeloid leukemia.
Increased expression of RUNX3 inhibits normal human myeloid development.
Luxeptinib (CG-806) targets FLT3 and clusters of kinases operative in acute myeloid leukemia.
Ceramide Accumulation Induces the Integrated Stress Response in AML.
Hypomethylating agent and venetoclax with FLT3 inhibitor "triplet" therapy in older/unfit patients with FLT3 mutated AML.
A phase 1b study of atezolizumab in combination with guadecitabine for the treatment of acute myeloid leukemia.
The antagonistic duality of NPM1 mutations in AML.
Advancing the standard: venetoclax combined with intensive induction and consolidation therapy for acute myeloid leukemia.
Lenalidomide promotes the development of TP53-mutated therapy-related myeloid neoplasms.
Distinct patterns of clonal evolution drive myelodysplastic syndrome progression to secondary acute myeloid leukemia  .
Loss of PRMT7 reprograms glycine metabolism to selectively eradicate leukemia stem cells in CML.
eEF2K activity determines synergy to co-treatment of cancer cells with PI3K and MEK inhibitors.
A Novel HNRNPH1::ERG Rearrangement in Aggressive Acute Myeloid Leukemia.
Rare evolution of CSF3R-mutated chronic neutrophilic leukemia to t(4;12)(q12;p13) acute myeloid leukemia with SETBP1 mutation.
Real-world effectiveness of CPX-351 vs venetoclax and azacitidine in acute myeloid leukemia.
Prospective Comparison of Outcomes with Azacitidine and Decitabine in AML Patients Ineligible for Intensive Chemotherapy.
Cardiovascular Disease Among Patients With AML and CHIP-Related Mutations.
Multiple cells of origin in common with various types of mouse N-Myc acute leukemia.
Antigen presentation safeguards the integrity of the hematopoietic stem cell pool.
Combinatorial GxGxE CRISPR screen identifies SLC25A39 in mitochondrial glutathione transport linking iron homeostasis to OXPHOS.
Beyond BCL-2 Inhibition in Acute Myeloid Leukemia: Other Approaches to Leverage the Apoptotic Pathway.
How I treat high-risk acute myeloid leukemia using pre-emptive adoptive cellular immunotherapy.
Machine Learning to Predict Risk of Relapse Using Cytologic Image Markers in Patients With Acute Myeloid Leukemia Posthematopoietic Cell Transplantation.
Venetoclax plus 3 + 7 daunorubicin and cytarabine chemotherapy as first-line treatment for adults with acute myeloid leukaemia: a multicentre, single-arm, phase 2 trial.
Metformin for Treatment of Cytopenias in Children and Young Adults with Fanconi Anemia.
RUNX1 mutations contribute to the progression of MDS due to disruption of antitumor cellular defense: a study on patients with lower-risk MDS.
Overlapping and unique substrate specificities of ST3GAL1 and 2 during hematopoietic and megakaryocytic differentiation.
CRISPR-Cas9 mediated generation of a conditional poly(A) binding protein nuclear 1 (Pabpn1) mouse model reveals an essential role for hematopoietic stem cells.
Metabolic reprogramming by ex vivo glutamine inhibition endows CAR-T cells with less-differentiated phenotype and persistent antitumor activity.
Leukemia and Heart Disease: Lessons at the Intersection of the Most Feared CHIP Outcomes.
Anti-CCR9 Chimeric Antigen Receptor T cells for T Cell Acute Lymphoblastic Leukemia.

EMBO Mol Med. 2022 May 06. e15203

Inhibition of pyrimidine biosynthesis targets protein translation in acute myeloid leukemia.

Joan So, Alexander C Lewis, Lorey K Smith, Kym Stanley, Rheana Franich, David Yoannidis, Lizzy Pijpers, Pilar Dominguez, Simon J Hogg, Stephin J Vervoort, Fiona C Brown, Ricky W Johnstone, Gabrielle McDonald, Danielle B Ulanet, Josh Murtie, Emily Gruber, Lev M Kats.

  The mitochondrial enzyme dihydroorotate dehydrogenase (DHODH) catalyzes one of the rate-limiting steps in de novo pyrimidine biosynthesis, a pathway that provides essential metabolic precursors for nucleic acids, glycoproteins, and phospholipids. DHODH inhibitors (DHODHi) are clinically used for autoimmune diseases and are emerging as a novel class of anticancer agents, especially in acute myeloid leukemia (AML) where pyrimidine starvation was recently shown to reverse the characteristic differentiation block in AML cells. Herein, we show that DHODH blockade rapidly shuts down protein translation in leukemic stem cells (LSCs) and has potent and selective activity against multiple AML subtypes. Moreover, we find that ablation of CDK5, a gene that is recurrently deleted in AML and related disorders, increases the sensitivity of AML cells to DHODHi. Our studies provide important molecular insights and identify a potential biomarker for an emerging strategy to target AML.

Keywords:  DHODH; acute myeloid leukemia; leukemic stem cells; protein translation

DOI:  https://doi.org/10.15252/emmm.202115203
Blood Adv. 2022 May 05. pii: bloodadvances.2022007083. [Epub ahead of print]

Treatment-free remission after ceasing venetoclax-based therapy in patients with acute myeloid leukemia.

Chong Chyn Chua, Danielle Hammond, Andrew Kent, Ing Soo Tiong, Marina Y Konopleva, Daniel A Pollyea, Courtney D DiNardo, Andrew H Wei.

The clinical benefit of adding venetoclax (VEN) to hypomethylating agents or low dose cytarabine in older and/or unfit patients with newly diagnosed acute myeloid leukemia (AML) has been confirmed in phase 3 studies. With the increased uptake of VEN-based therapies for patients with AML, a pertinent question is whether treatment can be safely ceased among patients who have achieved sustained remission. We hypothesized that a proportion of patients opting to cease therapy may benefit from a treatment-free remission (TFR) period without indefinite treatment. We report the retrospective outcomes of 29 patients in remission for a minimum of 12 months on VEN-based therapy, with 55% continuing therapy (CONT) until disease progression and the 45% electively ceasing treatment (STOP). With follow up exceeding 5 years, we observed a median TFR lasting 45.8 months among the STOP cohort, with >50% of patients still in sustained remission at the data cut-off. The risk of relapse and duration of relapse-free and overall survival were similar between the two cohorts. Factors favoring sustained TFR within the cohort included NPM1 and/or IDH2 mutation at diagnosis, complete remission without measurable residual disease, and at least 12 months of VEN-based combination therapy prior to treatment cessation.

DOI: https://doi.org/10.1182/bloodadvances.2022007083
Leukemia. 2022 Apr 30.

Increased expression of RUNX3 inhibits normal human myeloid development.

Ana Catarina Menezes, Rachel Jones, Alina Shrestha, Rachael Nicholson, Adam Leckenby, Aleksandra Azevedo, Sara Davies, Sarah Baker, Amanda F Gilkes, Richard L Darley, Alex Tonks.

RUNX3 is a transcription factor dysregulated in acute myeloid leukemia (AML). However, its role in normal myeloid development and leukemia is poorly understood. Here we investigate RUNX3 expression in both settings and the impact of its dysregulation on myelopoiesis. We found that RUNX3 mRNA expression was stable during hematopoiesis but decreased with granulocytic differentiation. In AML, RUNX3 mRNA was overexpressed in many disease subtypes, but downregulated in AML with core binding factor abnormalities, such as RUNX1::ETO. Overexpression of RUNX3 in human hematopoietic stem and progenitor cells (HSPC) inhibited myeloid differentiation, particularly of the granulocytic lineage. Proliferation and myeloid colony formation were also inhibited. Conversely, RUNX3 knockdown did not impact the myeloid growth and development of human HSPC. Overexpression of RUNX3 in the context of RUNX1::ETO did not rescue the RUNX1::ETO-mediated block in differentiation. RNA-sequencing showed that RUNX3 overexpression downregulates key developmental genes, such as KIT and RUNX1, while upregulating lymphoid genes, such as KLRB1 and TBX21. Overall, these data show that increased RUNX3 expression observed in AML could contribute to the developmental arrest characteristic of this disease, possibly by driving a competing transcriptional program favoring a lymphoid fate.

DOI: https://doi.org/10.1038/s41375-022-01577-2
Mol Cancer Ther. 2022 May 02. pii: molcanther.0832.2021. [Epub ahead of print]

Luxeptinib (CG-806) targets FLT3 and clusters of kinases operative in acute myeloid leukemia.

William G Rice, Stephen B Howell, Hongying Zhang, Nasrin Rastgoo, Andrea Local, Stephen E Kurtz, Pierrette Lo, Daniel Bottomly, Beth Wilmot, Shannon K McWeeney, Brian J Druker, Jeffrey W Tyner.

Luxeptinib (CG-806) simultaneously targets FLT3 and select other kinase pathways operative in myeloid malignancies. We investigated the range of kinases it inhibits, its cytotoxicity landscape ex vivo with acute myeloid leukemia (AML) patient samples, and its efficacy in xenograft models. Luxeptinib inhibits wild type and many of the clinically relevant mutant forms of FLT3 at low nanomolar concentrations. It is a more potent inhibitor of the activity of FLT3-ITD, FLT3 kinase domain and gatekeeper mutants than against wild type FLT3. Broad kinase screens disclosed that it also inhibits other kinases that can drive oncogenic signaling and rescue pathways, but spares kinases known to be associated with clinical toxicity. In vitro profiling of luxeptinib against 186 AML fresh patient samples demonstrated greater potency relative to other FLT3 inhibitors, including cases with mutations in FLT3, IDH1/2, ASXL1, NPM1, SRSF2, TP53 or RAS, and activity was documented in a xenograft AML model. Luxeptinib administered continuously PO every 12 h at a dose that yielded a mean Cmin plasma concentration of 1.0 {plus minus} 0.3 µM (SEM) demonstrated strong antitumor activity but no myelosuppression or evidence of tissue damage in mice or dogs in acute toxicology studies. On the basis of these studies, luxeptinib was advanced into a phase 1 trial for patients with AML and myelodysplastic/myeloproliferative neoplasms (MDS/MPN).

DOI: https://doi.org/10.1158/1535-7163.MCT-21-0832
Cancer Discov. 2022 May 06. OF1

Ceramide Accumulation Induces the Integrated Stress Response in AML.

High ceramide levels promote the apoptotic integrated stress response in acute myeloid leukemia (AML).

DOI: https://doi.org/10.1158/2159-8290.CD-RW2022-083
Blood Cancer J. 2022 May 02. 12(5): 77

Hypomethylating agent and venetoclax with FLT3 inhibitor "triplet" therapy in older/unfit patients with FLT3 mutated AML.

Musa Yilmaz, Hagop Kantarjian, Nicholas J Short, Patrick Reville, Marina Konopleva, Tapan Kadia, Courtney DiNardo, Gautam Borthakur, Naveen Pemmaraju, Abhishek Maiti, Elias Jabbour, Nitin Jain, Ghayas Issa, Koichi Takahashi, Koji Sasaki, Maro Ohanian, Sherry Pierce, Guillin Tang, Sanam Loghavi, Keyur Patel, Sa A Wang, Guillermo Garcia-Manero, Michael Andreeff, Farhad Ravandi, Naval Daver.

In older/unfit newly diagnosed patients with FLT3 mutated acute myeloid leukemia (AML), lower intensity chemotherapy (LIC) in combination with either a FLT3 inhibitor or with venetoclax results in poor overall survival (median 8 to 12.5 months). We performed a retrospective analysis of 87 newly diagnosed FLT3 mutated AML patients treated on triplet (LIC + FLT3 inhibitor + Venetoclax, [N = 27]) and doublet (LIC + FLT3 inhibitor, [N = 60]) regimens at our institution. Data were collected from prospective clinical trials in 75% (N = 65) and 25% (N = 22) who received the same treatment regimens outside of a clinical trial. Triplet therapy was associated with significantly higher rates of complete remission (CR) (67% versus 32%, P = 0.002), CR/CRi (93% versus 70%, P = 0.02), FLT3-PCR negativity (96% versus 54%, P < 0.01), and flow-cytometry negativity (83% versus 38%, P < 0.01) than doublets. At the end of the first cycle, the median time to ANC > 0.5 (40 versus 21 days, P = 0.15) and platelet > 50 K (29 versus 25 days, P = 0.6) among responders was numerically longer with triplets, but 60-day mortality was similar (7% v 10%). With a median follow-up of 24 months (median 12 months for triplet arm, and 63 months for doublet arm), patients receiving a triplet regimen had a longer median overall survival (not reached versus 9.5 months, P < 0.01). LIC combined with FLT3 inhibitor and venetoclax (triplet) may be an effective frontline regimen for older/unfit FLT3 mutated AML that should be further validated prospectively.

DOI: https://doi.org/10.1038/s41408-022-00670-0
Leuk Lymphoma. 2022 May 01. 1-9

A phase 1b study of atezolizumab in combination with guadecitabine for the treatment of acute myeloid leukemia.

Thomas Prebet, Aaron D Goldberg, Joseph G Jurcic, Samer Khaled, Monique Dail, Yuning Feng, Cherie Green, Chunze Li, Connie Ma, Bruno C Medeiros, Mark Yan, Michael R Grunwald.

  This phase 1 b study evaluated the safety, efficacy, and pharmacokinetics of atezolizumab in combination with guadecitabine in patients with relapsed/refractory (R/R) or first-line acute myeloid leukemia (AML). Patients received atezolizumab 840 mg (days [D] 8 and 22) and guadecitabine 60 mg/m2 (D1 and D5) over 28-day cycles. Sixteen patients (median age 73.0 years) enrolled (R/R cohort, n = 11; first-line cohort, n = 5). All patients reported at least 1 AE; 15 patients (93.8%) reported grade ≥ 3 AEs, and 15 patients (93.8%) reported SAEs. Fourteen of the 16 patients (87.5%) died during the trial period due to disease progression (8/14) or AEs (6/14), hence the study was terminated early. One patient (from the R/R AML cohort) achieved a response (CR with incomplete platelet recovery) with a DOR of 27.8 months at study termination. Atezolizumab plus guadecitabine had limited clinical activity in AML and an overall unfavorable benefit-risk profile at the investigated dose levels.

Keywords:  Oncology; PD-L1 inhibitor; checkpoint inhibitor

DOI:  https://doi.org/10.1080/10428194.2022.2057484
Blood Adv. 2022 May 04. pii: bloodadvances.2022007420. [Epub ahead of print]

The antagonistic duality of NPM1 mutations in AML.

Irum Khan, Andrei Gartel.

DOI: https://doi.org/10.1182/bloodadvances.2022007420
Ther Adv Hematol. 2022 ;13 20406207221093964

Advancing the standard: venetoclax combined with intensive induction and consolidation therapy for acute myeloid leukemia.

Curtis A Lachowiez, Himachandana Atluri, Courtney D DiNardo.

  The B-cell lymphoma 2 (BCL-2) inhibitor venetoclax (VEN) in combination with lower-intensity therapy is an efficacious treatment for acute myeloid leukemia (AML). VEN in combination with the hypomethylating agent azacitidine improved rates of response and measurable residual disease (MRD)-negative remissions in addition to overall survival in the pivotal phase 3 VIALE-A trial compared with azacitidine monotherapy and has since emerged as the current standard of care in older or unfit patients with AML. In younger, fit patients with AML, intensive induction and consolidation chemotherapy (IC) is commonly employed as frontline therapy; however, relapse remains the principal cause of treatment failure in approximately 30-40% of patients. Improved IC regimens that increase MRD-negative response rates, result in durable remissions, and enable transition to curative allogeneic hematopoietic stem cell transplantation in appropriate patients remain an area of active inquiry. Preliminary results from trials investigating the combination of VEN with IC have reported promising findings to date, with composite complete remission and MRD-negative remission rates of approximately 89-94% and 82-93%, respectively, correlating with improved 12-month event-free and overall survival compared to historical outcomes with IC. Herein, we discuss ongoing trials investigating VEN in combination with IC in addition to outcomes within specific molecularly defined subgroups; review the molecular mechanisms of sensitivity and resistance to VEN, and highlight future combinations of VEN with novel targeted therapies for the treatment of AML.

Keywords:  acute myeloid leukemia; intensive induction; venetoclax

DOI:  https://doi.org/10.1177/20406207221093964
Blood. 2022 May 05. pii: blood.2021014956. [Epub ahead of print]

Lenalidomide promotes the development of TP53-mutated therapy-related myeloid neoplasms.

Adam S Sperling, Veronica Analia Guerra, James A Kennedy, Yuanqing Yan, Joanne I Hsu, Feng Wang, Andrew T Nguyen, Peter G Miller, Marie E McConkey, Vanessa A Quevedo Barrios, Ken Furudate, Linda Zhang, Rashmi Kanagal-Shamanna, Jianhua Zhang, Latasha D Little, Curtis E Gumbs, Naval G Daver, Courtney D DiNardo, Tapan M Kadia, Farhad Ravandi, Hagop M Kantarjian, Guillermo Garcia-Manero, Andrew Futreal, Benjamin L Ebert, Koichi Takahashi.

There is a growing body of evidence that therapy-related myeloid neoplasms (t-MNs) with driver gene mutations arise in the background of clonal hematopoiesis (CH) under the positive selective pressure of chemo- and radiation therapies (CRT). Uncovering the exposure relationships that provide selective advantage to specific CH mutations is critical to understanding the pathogenesis and etiololgy of t-MNs. In a systematic analysis of 416 patients with t-MN and detailed prior exposure history, we found that TP53 mutations were significantly associated with prior treatment with thalidomide analogs, specifically lenalidomide. We demonstrated experimentally that lenalidomide treatment provides a selective advantage to Trp53-mutant hematopoietic stem and progenitor cells (HSPCs) in vitro and in vivo, the effect of which was specific to Trp53-mutant HSPCs and was not observed in HSPCs with other CH mutations. Due to differences in CK1a degradation, pomalidomide treatment did not provide an equivalent level of selective advantage to Trp53-mutant HSPCs providing a biological rationale for its use in patients at high risk for t-MN. These findings highlight the role of lenalidomide treatment in promoting TP53-mutated t-MNs and offer a potential alternative strategy to mitigate the risk of t-MN development.

DOI: https://doi.org/10.1182/blood.2021014956
Blood Cancer Discov. 2022 May 06. pii: bloodcandisc.BCD-21-0128-E.2021. [Epub ahead of print]

Distinct patterns of clonal evolution drive myelodysplastic syndrome progression to secondary acute myeloid leukemia  .

Tiffany Guess, Chad R Potts, Pawan Bhat, Justin A Cartailler, Austin Brooks, Clinton Holt, Ashwini Yenamandra, Ferrin C Wheeler, Michael R Savona, Jean-Philippe Cartailler, P Brent Ferrell.

Clonal evolution in myelodysplastic syndrome (MDS) can result in clinical progression and secondary acute myeloid leukemia (sAML). To dissect changes in clonal architecture associated with this progression, we performed single-cell genotyping of paired MDS and sAML samples from 18 patients. Analysis of single-cell genotypes revealed patient-specific clonal evolution and enabled assessment of single-cell mutational co-occurrence. We discovered changes in clonal architecture proceed via distinct patterns, classified as static or dynamic, with dynamic clonal architectures having a more proliferative phenotype by blast count fold change. Proteogenomic analysis of a subset of patients confirmed pathogenic mutations were primarily confined to primitive and mature myeloid cells, though we also identify rare, but present, mutations in lymphocyte subsets. Single-cell transcriptomic analysis of paired sample sets further identified gene sets and signaling pathways involved in two cases of progression. Together, these data define serial changes in the MDS clonal landscape with clinical and therapeutic implications.

DOI: https://doi.org/10.1158/2643-3230.BCD-21-0128
Cell Metab. 2022 Apr 26. pii: S1550-4131(22)00131-0. [Epub ahead of print]

Loss of PRMT7 reprograms glycine metabolism to selectively eradicate leukemia stem cells in CML.

Chang Liu, Waiyi Zou, Danian Nie, Shuyi Li, Chen Duan, Min Zhou, Peilong Lai, Shengyong Yang, Sen Ji, Yangqiu Li, Mei Mei, Shilai Bao, Yanli Jin, Jingxuan Pan.

  Our group has reported previously on the role of various members of the protein arginine methyltransferase (PRMT) family, which are involved in epigenetic regulation, in the progression of leukemia. Here, we explored the role of PRMT7, given its unique function within the PRMT family, in the maintenance of leukemia stem cells (LSCs) in chronic myeloid leukemia (CML). Genetic loss of Prmt7, and the development and testing of a small-molecule specific inhibitor of PRMT7, showed that targeting PRMT7 delayed leukemia development and impaired self-renewal of LSCs in a CML mouse model and in primary CML CD34+ cells from humans without affecting normal hematopoiesis. Mechanistically, loss of PRMT7 resulted in reduced expressions of glycine decarboxylase, leading to the reprograming of glycine metabolism to generate methylglyoxal, which is detrimental to LSCs. These findings link histone arginine methylation with glycine metabolism, while suggesting PRMT7 as a potential therapeutic target for the eradication of LSCs in CML.

Keywords:  GLDC; JS1310; PRMT7; chronic myelogenous leukemia; epigenetic; glycine metabolism; leukemia stem cells; self-renewal; survival

DOI:  https://doi.org/10.1016/j.cmet.2022.04.004
Mol Cell Proteomics. 2022 May 02. pii: S1535-9476(22)00048-2. [Epub ahead of print] 100240

eEF2K activity determines synergy to co-treatment of cancer cells with PI3K and MEK inhibitors.

Maruan Hijazi, Pedro Casado, Nosheen Akhtar, Saul Alvarez-Teijeiro, Vinothini Rajeeve, Pedro R Cutillas.

  PI3K-mTOR and MEK/MAPK are the most frequently dysregulated signaling pathways in cancer. A problem that limits the success of therapies that target individual PI3K-MAPK members is that these pathways converge to regulate downstream functions and often compensate each other, leading to drug resistance and transient responses to therapy. In order to overcome resistance, therapies based on co-treatments with PI3K/AKT and MEK/MAPK inhibitors are now being investigated in clinical trials but the mechanisms of sensitivity to co-treatment are not fully understood. Using LC-MS/MS based phosphoproteomics, we found that eEF2K, a key convergence point downstream of MAPK and PI3K pathways, mediates synergism to co-treatment with trametinib plus pictilisib (which target MEK1/2 and PI3Kα/δ, respectively). Inhibition of eEF2K by siRNA or with a small molecule inhibitor reversed the anti-proliferative effects of the co-treatment with PI3K plus MEK inhibitors in a cell model specific manner. Systematic analysis in 12 acute myeloid leukemia (AML) cell lines revealed that eEF2K activity was increased in cells for which PI3K plus MEKi co-treatment is synergistic, while PKC potentially mediated resistance to such co-treatment. Together, our study uncovers eEF2K activity as a key mediator of responses to PI3Ki plus MEKi and as a potential biomarker to predict synergy to co-treatment in cancer cells.

Keywords:  AML; biomarkers; cancer; combination therapy; eEF2K; kinase activity; phosphoproteomics; synergy

DOI:  https://doi.org/10.1016/j.mcpro.2022.100240
Genes Chromosomes Cancer. 2022 May 03.

A Novel HNRNPH1::ERG Rearrangement in Aggressive Acute Myeloid Leukemia.

Feiling Jiang, Xingping Lang, Nan Chen, Liqin Jin, Lingfeng Liu, Xiaobin Wei, Jianhua Pan, Feng Yu, Angella Blake, Sheng Xiao.

  FUS::ERG rearrangement is a recurrent abnormality seen in a subgroup of acute myeloid leukemia (AML) with a poor prognosis. We described here a novel HNRNPH1::ERG rearrangement in a de novo AML. The patient was unresponsive to routine chemotherapy and succumbed to the disease just 3 months after diagnosis. Two additional cases of AML with HNRNPH1::ERG rearrangement were discovered by searching a publicly available sequencing database. The three patients share several clinical phenotypes with the FUS::ERG rearranged AML, including high blast count at diagnosis, pediatric or young adult-onset, and poor overall survival. In addition, hnRNPH1 and FUS are both hnRNP family members, a group of RNA-biding proteins functioning in RNA metabolism and transport. Therefore, we suggest that patients with HNRNPH1::ERG or FUS::ERG rearrangement belong to the same distinct clinicopathologic subtype of AML, i.e., AML with ERG rearrangement. Based on a previous study showing that FUS::ERG binds to the retinoic acid-responsive elements (RARE) and that All-trans retinoic acid (ATRA) induced cell differentiation of AML cells, we support the clinical evaluation of an APL-like therapeutic regimen for AML with ERG rearrangement.

Keywords:  AML; ERG; HNRNPH1

DOI:  https://doi.org/10.1002/gcc.23051
Leuk Res Rep. 2022 ;17 100311

Rare evolution of CSF3R-mutated chronic neutrophilic leukemia to t(4;12)(q12;p13) acute myeloid leukemia with SETBP1 mutation.

Maki Hirao, Kentaro Watanabe, Yuiko Tsukada, Hisako Kunieda, Makoto Osada, Kohei Yamazaki, Ryunosuke Denda, Shinichiro Okamoto, Takahide Kikuchi.

  Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative disease accompanied by mutations in CSF3R. Here, we present a patient with CNL who developed to acute myeloid leukemia (AML) at the same time that a t(4;12)(q12;p13) translocation appeared. The uniqueness of this cytogenetic abnormality led us to delineate the molecular aberrations relevant for clonal evolution. While the CSF3R mutation was present throughout the course of the disease, the SETBP1 mutation was newly acquired at the AML transformation. The present case suggests that careful monitoring of t(4;12)(q12;p13) and SETBP1 is crucial to predict AML evolution in CNL patients.

Keywords:  Acute myeloid leukemia; Chronic neutrophilic leukemia; SETBP1; t(4 ； 12)(q12 ； p13)

DOI:  https://doi.org/10.1016/j.lrr.2022.100311
Blood Adv. 2022 May 04. pii: bloodadvances.2022007265. [Epub ahead of print]

Real-world effectiveness of CPX-351 vs venetoclax and azacitidine in acute myeloid leukemia.

Andrew H Matthews, Alexander E Perl, Selina M Luger, Alison W Loren, Saar I Gill, David L Porter, Daria V Babushok, Ivan Maillard, Martin P Carroll, Noelle V Frey, Elizabeth Hexner, Mary Ellen Martin, Shannon R McCurdy, Edward A Stadtmauer, Vikram R Paralkar, Ximena Jordan Bruno, Wei-Ting Hwang, David Margolis, Keith W Pratz.

CPX-351 and venetoclax and azacitidine (ven/aza) are both indicated as initial therapy for acute myeloid leukemia (AML) in older adults. In the absence of prospective randomized comparisons of these regimens, we used retrospective observational data to evaluate various outcomes for patients with newly diagnosed AML receiving either CPX-351 (n=217) or ven/aza (n=439). This study used both a nationwide electronic health record (EHR)-derived de-identified database and the University of Pennsylvania EHR. Our study includes 217 patients who received CPX-351 and 439 who received venetoclax/azacitidine. Ven/aza patients were older, more likely to be treated in the community, and more likely to have a diagnosis of de novo AML. Other baseline covariates were not statistically significantly different between the groups. Median overall survival (OS) for all patients was 12 months and did not differ based upon therapy (13 months for CPX-351 versus 11 months for ven/aza, HR 0.88, 95% CI 0.71-1.08, p = 0.22). Overall survival was similar across multiple sensitivity analyses. Regarding safety outcomes, early mortality was similar (10% vs. 13% at 60 days). However, documented infections were higher with CPX-351 as were rates of febrile neutropenia. Hospital length of stay, including any admission prior to next cycle of therapy, was more than twice as long for CPX-351. In this large multi-center real word dataset, there was no statistically significant difference in OS. Prospective randomized studies with careful attention to side effects, quality of life, and impact on transplant outcomes are needed in these populations.

DOI: https://doi.org/10.1182/bloodadvances.2022007265
Blood. 2022 05 04. pii: blood.2022015832. [Epub ahead of print]

Prospective Comparison of Outcomes with Azacitidine and Decitabine in AML Patients Ineligible for Intensive Chemotherapy.

Amer M Zeidan, Pierre Fenaux, Marco Gobbi, Jiri Mayer, Gail J Roboz, Jürgen Krauter, Tadeusz Robak, Hagop M Kantarjian, Jan Novak, Wieslaw Wiktor Jedrzejczak, Xavier Thomas, Mario Ojeda-Uribe, Yasushi Miyazaki, Yoo Hong Min, Su-Peng Yeh, Joseph M Brandwein, Liana Todorovd Gercheva, Judit Demeter, Elizabeth A Griffiths, Karen Wl Yee, Jean-Pierre J Issa, Jan Philipp Bewersdorf, Harold Neal Keer, Yong Hao, Mohammad Azab, Hartmut Döhner.

DOI: https://doi.org/10.1182/blood.2022015832
JACC CardioOncol. 2022 Mar;4(1): 38-49

Cardiovascular Disease Among Patients With AML and CHIP-Related Mutations.

Oscar Calvillo-Argüelles, Alice Schoffel, José-Mario Capo-Chichi, Husam Abdel-Qadir, Andre Schuh, Montserrat Carrillo-Estrada, Shiying Liu, Vikas Gupta, Aaron D Schimmer, Karen Yee, Liran I Shlush, Pradeep Natarajan, Paaladinesh Thavendiranathan.

  Background: Clonal hematopoiesis of indeterminate potential (CHIP) is a novel cardiovascular disease (CVD) risk factor in individuals without acute myeloid leukemia (AML).Objectives: The aim of this study was to examine the association between mutations associated with CHIP (CHIP-related mutations) identified in patients at AML diagnosis and the risk for cardiovascular events (CVEs).
Methods: This was a retrospective cohort study of 623 patients with AML treated between 2015 and 2018 who underwent DNA analysis. Cause-specific hazard regression models were used to study the associations between pathogenic mutations in common CHIP-related genes (DNMT3A, TET2, ASXL1, JAK2, TP53, SRSF2, and SF3B1) and the rate of CVEs (heart failure hospitalization, acute coronary syndrome, coronary artery revascularization, ischemic stroke, venous thromboembolism, and CVD death) and between CVE development and all-cause mortality.
Results: Patients were 64.6 ± 15.3 years of age, 265 (42.5%) were women, and 63% had at least 1 CHIP-related mutation. Those with CHIP-related mutations were older (69.2 ± 12.3 vs 56.6 ± 16.6 years; P < 0.001) and had a greater prevalence of CVD risk factors and CVD history. In adjusted analysis, the presence of any CHIP-related mutation was associated with a higher rate of CVEs (HR: 1.74; 95% CI: 1.03-2.93; P = 0.037) among intensively treated patients (anthracycline based) but not the whole cohort (HR: 1.26; 95% CI: 0.81-1.97; P = 0.31). TP53 (HR: 4.18; 95% CI: 2.07-8.47; P < 0.001) and ASXL1 (HR: 2.37; 95% CI: 1.21-4.63; P = 0.012) mutations were associated with CVEs among intensively treated patients. Interval development of CVEs was associated with all-cause mortality (HR: 1.99; 95% CI: 1.45-2.73; P < 0.001).
Conclusions: Among patients with AML treated with intensive chemotherapy, mutations in CHIP-related genes were associated with an increased risk for developing incident CVEs after AML diagnosis.

Keywords:  ACS, acute coronary syndrome; AML, acute myeloid leukemia; CHIP, clonal hematopoiesis of indeterminate potential; CVD, cardiovascular disease; CVE, cardiovascular event; CVRF, cardiovascular risk factor; HF, heart failure; LVEF, left ventricular ejection fraction; MACCE, major adverse cardiovascular and cerebrovascular event(s); NGS, next-generation sequencing; VAF, variant allele frequency; acute myeloid leukemia; allo-HCT, allogeneic hematopoietic cell transplantation; cardiovascular diseases; clonal hematopoiesis; clonal hematopoiesis of indeterminate potential

DOI:  https://doi.org/10.1016/j.jaccao.2021.11.008
Leuk Res. 2022 Apr 25. pii: S0145-2126(22)00069-8. [Epub ahead of print]117 106843

Multiple cells of origin in common with various types of mouse N-Myc acute leukemia.

Haitao Bai, Qingyun Zhang, Sen Zhang, Jinhong Wang, Bingqing Luo, Yan Dong, Jianzhao Gao, Tao Cheng, Fang Dong, Hideo Ema.

  Little is known regarding whether the cell of origin differs among different leukemia types. To address this fundamental issue, we determined the cell of origin in five distinct types of acute leukemia induced by N-Myc overexpression in mice. CD150+CD48-CD41-CD34-c-Kit+Sca-1+Lin- (KSL) (HSC1) cells, CD150-CD48-CD41-CD34-KSL (HSC2) cells, CD150+CD41+CD34-KSL (HPC1) cells, CD150+CD41+CD34+KSL (HPC2) cells, and CD150-CD41-CD34+KSL (HPC3) cells were purified from the bone marrow of adult C57BL/6 mice, transduced with the N-Myc retrovirus vector, and transplanted into lethally irradiated mice. B-cell acute lymphoblastic leukemia (B-ALL), T-cell acute lymphoblastic leukemia (T-ALL), acute myeloid leukemia (AML), acute undifferentiated leukemia (AUL), and mixed phenotype acute leukemia (MPAL) developed from five populations. RNA sequencing data supported the phenotypical diagnoses of leukemia, except that AUL appeared transcriptionally close to T-ALL. Whole-genome sequencing revealed that retroviral integration sites were irrelevant to the leukemia types and that T-ALL and AML of MPAL shared the same integration site and many gene mutations, suggesting their common origin. Additionally, leukemic stem cells were identified in the KSL cell population, suggesting that the phenotypes of leukemic stem cells are irrelevant to leukemia types. This study provides experimental evidence for the similar and multiple cells of origin in acute leukemia.

Keywords:  Acute myeloid leukemia (AML); Acute undifferentiated leukemia (AUL); B-cell acute lymphoblastic leukemia (B-ALL); Hematopoietic progenitor cells (HPCs); Hematopoietic stem cells (HSCs); Leukemogenesis; Mixed phenotype acute leukemia (MPAL); N-Myc; T-cell acute lymphoblastic leukemia (T-ALL); Whole-genome sequencing

DOI:  https://doi.org/10.1016/j.leukres.2022.106843
Cell Stem Cell. 2022 May 05. pii: S1934-5909(22)00160-6. [Epub ahead of print]29(5): 760-775.e10

Antigen presentation safeguards the integrity of the hematopoietic stem cell pool.

Pablo Hernández-Malmierca, Dominik Vonficht, Alexandra Schnell, Hannah J Uckelmann, Alina Bollhagen, Mohamed A A Mahmoud, Sophie-Luise Landua, Elise van der Salm, Christine L Trautmann, Simon Raffel, Florian Grünschläger, Raphael Lutz, Michael Ghosh, Simon Renders, Nádia Correia, Elisa Donato, Karin O Dixon, Christoph Hirche, Carolin Andresen, Claudia Robens, Paula S Werner, Tobias Boch, David Eisel, Wolfram Osen, Franziska Pilz, Adriana Przybylla, Corinna Klein, Frank Buchholz, Michael D Milsom, Marieke A G Essers, Stefan B Eichmüller, Wolf-Karsten Hofmann, Daniel Nowak, Daniel Hübschmann, Michael Hundemer, Christian Thiede, Lars Bullinger, Carsten Müller-Tidow, Scott A Armstrong, Andreas Trumpp, Vijay K Kuchroo, Simon Haas.

  Hematopoietic stem and progenitor cells (HSPCs) are responsible for the production of blood and immune cells. Throughout life, HSPCs acquire oncogenic aberrations that can cause hematological cancers. Although molecular programs maintaining stem cell integrity have been identified, safety mechanisms eliminating malignant HSPCs from the stem cell pool remain poorly characterized. Here, we show that HSPCs constitutively present antigens via major histocompatibility complex class II. The presentation of immunogenic antigens, as occurring during malignant transformation, triggers bidirectional interactions between HSPCs and antigen-specific CD4+ T cells, causing stem cell proliferation, differentiation, and specific exhaustion of aberrant HSPCs. This immunosurveillance mechanism effectively eliminates transformed HSPCs from the hematopoietic system, thereby preventing leukemia onset. Together, our data reveal a bidirectional interaction between HSPCs and CD4+ T cells, demonstrating that HSPCs are not only passive receivers of immunological signals but also actively engage in adaptive immune responses to safeguard the integrity of the stem cell pool.

Keywords:  CD4(+) T cells; acute myeloid leukemia; antigen presentation; hematopoietic stem cells; immune regulation; immunosurveillance; leukemia

DOI:  https://doi.org/10.1016/j.stem.2022.04.007
Nat Commun. 2022 May 05. 13(1): 2483

Combinatorial GxGxE CRISPR screen identifies SLC25A39 in mitochondrial glutathione transport linking iron homeostasis to OXPHOS.

Xiaojian Shi, Bryn Reinstadler, Hardik Shah, Tsz-Leung To, Katie Byrne, Luanna Summer, Sarah E Calvo, Olga Goldberger, John G Doench, Vamsi K Mootha, Hongying Shen.

The SLC25 carrier family consists of 53 transporters that shuttle nutrients and co-factors across mitochondrial membranes. The family is highly redundant and their transport activities coupled to metabolic state. Here, we use a pooled, dual CRISPR screening strategy that knocks out pairs of transporters in four metabolic states - glucose, galactose, OXPHOS inhibition, and absence of pyruvate - designed to unmask the inter-dependence of these genes. In total, we screen 63 genes in four metabolic states, corresponding to 2016 single and pair-wise genetic perturbations. We recover 19 gene-by-environment (GxE) interactions and 9 gene-by-gene (GxG) interactions. One GxE interaction hit illustrates that the fitness defect in the mitochondrial folate carrier (SLC25A32) KO cells is genetically buffered in galactose due to a lack of substrate in de novo purine biosynthesis. GxG analysis highlights a buffering interaction between the iron transporter SLC25A37 (A37) and the poorly characterized SLC25A39 (A39). Mitochondrial metabolite profiling, organelle transport assays, and structure-guided mutagenesis identify A39 as critical for mitochondrial glutathione (GSH) import. Functional studies reveal that A39-mediated glutathione homeostasis and A37-mediated mitochondrial iron uptake operate jointly to support mitochondrial OXPHOS. Our work underscores the value of studying family-wide genetic interactions across different metabolic environments.

DOI: https://doi.org/10.1038/s41467-022-30126-9
Clin Lymphoma Myeloma Leuk. 2022 Apr 06. pii: S2152-2650(22)00113-6. [Epub ahead of print]

Beyond BCL-2 Inhibition in Acute Myeloid Leukemia: Other Approaches to Leverage the Apoptotic Pathway.

Abhishek Maiti, Bing Z Carter, Michael Andreeff, Marina Y Konopleva.

  BCL-2 inhibition has transformed the therapeutic landscape of acute myeloid leukemia (AML) but is not curative for the majority of patients. Consequently, there has been growing interest in targeting other facets of the apoptotic machinery to improve outcomes. These approaches include targeting the intrinsic and extrinsic apoptotic pathway, inducing apoptosis via p53 activation, and others. Targeting the intrinsic apoptotic pathway includes MCL-1 antagonism and BCL-xL inhibition. MCL-1 can be targeted via direct inhibitors as well as via indirect mechanisms to downregulate MCL-1 including inhibition of cyclin dependent kinases and Nedd8 activating enzyme. The extrinsic apoptotic pathway could be harnessed via inhibition of inhibitor of apoptosis proteins, agonism of the TNF-related apoptosis-inducing ligand receptors and inhibiting FLICE-like inhibitor protein. Approaches inducing p53-mediated apoptosis are being evaluated using inhibitors of MDM2, dual inhibitor of MDM2/X in TP53 wild-type AML and p53 reactivators in TP53-mutant myeloid disorders. Several such agents are in early clinical development and rationale combinations of these agents may help improving outcomes for patients with AML.

Keywords:  AML; BCL-xL; FLIP; IAP; MCL-1; MDM2; TRAIL

DOI:  https://doi.org/10.1016/j.clml.2022.04.001
Blood. 2022 May 05. pii: blood.2021012411. [Epub ahead of print]

How I treat high-risk acute myeloid leukemia using pre-emptive adoptive cellular immunotherapy.

Alexander Biederstädt, Katayoun Rezvani.

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a potentially curative treatment for patients with high risk acute leukemias, but unfortunately disease recurrence remains the major cause of death in these patients. Infusion of donor lymphocytes (DLI) has the potential to restore graft-versus-leukemia immunologic surveillance, however, efficacy varies across different hematologic entities. While relapsed chronic myeloid leukemia (CML), transplanted in chronic phase, has proven remarkably susceptible to DLI, response rates are more modest for relapsed acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). To prevent impending relapse, a number of groups have explored administering DLI pre-emptively upon detection of measurable residual disease (MRD) or mixed chimerism (MC). Evidence for the effectiveness of this strategy, while encouraging, comes from only a few, mostly single-center retrospective, non-randomized studies. This article seeks to i) discuss the available evidence supporting this approach while highlighting some of the inherent challenges of MRD-triggered treatment decisions post-transplant, ii) portray other forms of post-remission cellular therapies, including the role of next-generation target-specific immunotherapies and iii) provide a practical framework to support clinicians in their decision-making process when considering pre-emptive cellular therapy for this difficult-to-treat patient population.

DOI: https://doi.org/10.1182/blood.2021012411
JCO Clin Cancer Inform. 2022 May;6 e2100156

Machine Learning to Predict Risk of Relapse Using Cytologic Image Markers in Patients With Acute Myeloid Leukemia Posthematopoietic Cell Transplantation.

Sara Arabyarmohammadi, Patrick Leo, Vidya Sankar Viswanathan, Andrew Janowczyk, German Corredor, Pingfu Fu, Howard Meyerson, Leland Metheny, Anant Madabhushi.

PURPOSE: Allogenic hematopoietic stem-cell transplant (HCT) is a curative therapy for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Relapse post-HCT is the most common cause of treatment failure and is associated with a poor prognosis. Pathologist-based visual assessment of aspirate images and the manual myeloblast counting have shown to be predictive of relapse post-HCT. However, this approach is time-intensive and subjective. The premise of this study was to explore whether computer-extracted morphology and texture features from myeloblasts' chromatin patterns could help predict relapse and prognosticate relapse-free survival (RFS) after HCT.MATERIALS AND METHODS: In this study, Wright-Giemsa-stained post-HCT aspirate images were collected from 92 patients with AML/MDS who were randomly assigned into a training set (St = 52) and a validation set (Sv = 40). First, a deep learning-based model was developed to segment myeloblasts. A total of 214 texture and shape descriptors were then extracted from the segmented myeloblasts on aspirate slide images. A risk score on the basis of texture features of myeloblast chromatin patterns was generated by using the least absolute shrinkage and selection operator with a Cox regression model.
RESULTS: The risk score was associated with RFS in St (hazard ratio = 2.38; 95% CI, 1.4 to 3.95; P = .0008) and Sv (hazard ratio = 1.57; 95% CI, 1.01 to 2.45; P = .044). We also demonstrate that this resulting signature was predictive of AML relapse with an area under the receiver operating characteristic curve of 0.71 within Sv. All the relevant code is available at GitHub.
CONCLUSION: The texture features extracted from chromatin patterns of myeloblasts can predict post-HCT relapse and prognosticate RFS of patients with AML/MDS.

DOI: https://doi.org/10.1200/CCI.21.00156
Lancet Haematol. 2022 May 02. pii: S2352-3026(22)00106-5. [Epub ahead of print]

Venetoclax plus 3 + 7 daunorubicin and cytarabine chemotherapy as first-line treatment for adults with acute myeloid leukaemia: a multicentre, single-arm, phase 2 trial.

Huafeng Wang, Liping Mao, Min Yang, Pengxu Qian, Huan Lu, Hongyan Tong, Wanzhuo Xie, De Zhou, Xin Huang, Yungui Wang, Gaixiang Xu, Ying Lu, Juying Wei, Wenyuan Mai, Xiujin Ye, Haitao Meng, Yaojia Shen, Jian Huang, Wenjuan Yu, Jie Sun, Jianpeng Sheng, Xiaoyan Yan, Jie Jin, Hong-Hu Zhu.

BACKGROUND: Adults with acute myeloid leukaemia have unsatisfactory clinical outcomes and rates of complete remission. Venetoclax combined with azacytidine or low-dose cytarabine has shown efficacy in adults aged 75 years or older (or 18-74 years with comorbidities precluding intensive chemotherapy) with acute myeloid leukaemia. We aimed to investigate the activity and safety of venetoclax plus 3+7 daunorubicin and cytarabine chemotherapy in adults with acute myeloid leukaemia.METHODS: We conducted a two-stage, single-arm, phase 2 trial at three public hospitals in China. We enrolled patients aged 18-60 years with previously untreated de novo acute myeloid leukaemia and an Eastern Cooperative Oncology Group performance status of 0-2. Patients received induction treatment with intravenous daunorubicin (60 mg/m2 on days 1-3), intravenous cytarabine (100 mg/m2 on days 1-7), and oral venetoclax (100 mg on day 4, 200 mg on day 5, and 400 mg on days 6-11; DAV regimen). For induction therapy, the length of the treatment was 28-35 days per cycle and the number of treatment cycles was one or two. The primary endpoint was the composite complete remission rate (complete remission plus complete remission with incomplete blood cell count recovery) after one cycle of induction treatment, assessed in the as-treated population. Secondary endpoints were bone marrow measurable residual disease by flow cytometry, event-free survival, overall survival, and adverse events. This trial is ongoing and is registered with Chinese Clinical Trial Registry, ChiCTR2000041509.
FINDINGS: Between Dec 25, 2020, and July 7, 2021, 36 patients were assessed for eligibility and 33 were enrolled. 15 (45%) patients were men and 18 (55%) were women, and all were Asian. The composite complete remission rate after one cycle of DAV regimen was 91% (95% CI 76-98; 30 of 33 patients) in the entire cohort. 29 (97%) of 30 patients who reached complete remission had undetectable measurable residual disease (ie, <0·1%). Grade 3 or worse adverse events included neutropenia in 33 (100%) of 33 patients, thrombocytopenia in 33 (100%), anaemia in 33 (100%), febrile neutropenia in 18 (55%), pneumonia in seven (21%), and sepsis in four (12%). No treatment-related deaths occurred. With a median follow-up of 11 months (IQR 9-12), estimated 1-year overall survival was 97% (95% CI 91-100) and 1-year event-free survival was 72% (56-94).
INTERPRETATION: The DAV regimen represents an effective induction therapy for newly diagnosed adults with acute myeloid leukaemia, which resulted in a high rate of complete remission. These findings are an important contribution to the field, showing a safe strategy to incorporate venetoclax into the most common induction regimen used to treat newly diagnosed acute myeloid leukaemia internationally.
FUNDING: Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang, National Natural Science Foundation of China, Key Research and Development Program of Zhejiang.
TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

DOI: https://doi.org/10.1016/S2352-3026(22)00106-5
Blood Adv. 2022 May 02. pii: bloodadvances.2021006490. [Epub ahead of print]

Metformin for Treatment of Cytopenias in Children and Young Adults with Fanconi Anemia.

Jessica Pollard, Elissa Furutani, Shanshan Liu, Erica B Esrick, Laurie E Cohen, Jacob R Bledsoe, Chih-Wei Liu, Kun Lu, María José Ramírez, Jordi Surrallés, Maggie M Malsch, Ashley Kuniholm, Ashley Galvin, Myriam Armant, Annette S Kim, Kaitlyn Ballotti, Lisa A Moreau, Yu Zhou, Daria V Babushok, Farid Boulad, Clinton Carroll, Helge Hartung, Amy Hont, Taizo A Nakano, Timothy S Olson, Sei-Gyung K Sze, Alexis A Thompson, Marcin W Wlodarski, Xuesong Gu, Towia A Libermann, Alan D D'Andrea, Markus C P Grompe, Edie Weller, Akiko Shimamura.

Fanconi anemia (FA), a genetic disorder affecting DNA repair, is characterized by bone marrow failure and cancer susceptibility. In FA mouse models the biguanide metabolic agent metformin improves blood counts and delays tumor development. We conducted a single institution pilot study of metformin in non-diabetic patients with FA to assess feasibility and tolerability of metformin treatment and to determine whether metformin could improve blood counts. Fourteen of 15 patients with at least 1 cytopenia (hemoglobin <10g/dL, platelet count <100K cells/µL, or an absolute neutrophil count <1K cells/µL) were eligible to receive metformin for 6 months. Median patient age was 9.4 years (range 6.0-26.5), and 8/14 were male (57%). Thirteen of 14 subjects (93%) tolerated maximal dosing for age; one subject had dose reduction for grade 2 gastrointestinal symptoms. No subjects developed hypoglycemia or metabolic acidosis. No subjects had dose interruptions due to toxicity, and no grade 3 or higher adverse events attributed to metformin were observed. Hematologic response (HR) based on modified MDS IWG criteria was observed in 4 of 13 evaluable patients (30.8%, 90% CI:11.3 to 57.3). Median time to response was 84.5 days (range 71-128). Responses were noted in neutrophils (n=3), platelets (n=1), and red blood cells (n=1). No subjects met criteria for disease progression or relapse during treatment. Correlative studies explored potential mechanisms of metformin activity in FA. Plasma proteomics showed reduction in inflammatory pathways with metformin. We conclude that metformin is safe and tolerable in non-diabetic patients with FA and may provide therapeutic benefit. This trial is registered at www.clinicaltrials.gov as NCT03398824.

DOI: https://doi.org/10.1182/bloodadvances.2021006490
Leukemia. 2022 May 03.

RUNX1 mutations contribute to the progression of MDS due to disruption of antitumor cellular defense: a study on patients with lower-risk MDS.

Monika Kaisrlikova, Jitka Vesela, David Kundrat, Hana Votavova, Michaela Dostalova Merkerova, Zdenek Krejcik, Vladimir Divoky, Marek Jedlicka, Jan Fric, Jiri Klema, Dana Mikulenkova, Marketa Stastna Markova, Marie Lauermannova, Jolana Mertova, Jacqueline Soukupova Maaloufova, Anna Jonasova, Jaroslav Cermak, Monika Belickova.

Patients with lower-risk myelodysplastic syndromes (LR-MDS) have a generally favorable prognosis; however, a small proportion of cases progress rapidly. This study aimed to define molecular biomarkers predictive of LR-MDS progression and to uncover cellular pathways contributing to malignant transformation. The mutational landscape was analyzed in 214 LR-MDS patients, and at least one mutation was detected in 137 patients (64%). Mutated RUNX1 was identified as the main molecular predictor of rapid progression by statistics and machine learning. To study the effect of mutated RUNX1 on pathway regulation, the expression profiles of CD34 + cells from LR-MDS patients with RUNX1 mutations were compared to those from patients without RUNX1 mutations. The data suggest that RUNX1-unmutated LR-MDS cells are protected by DNA damage response (DDR) mechanisms and cellular senescence as an antitumor cellular barrier, while RUNX1 mutations may be one of the triggers of malignant transformation. Dysregulated DDR and cellular senescence were also observed at the functional level by detecting γH2AX expression and β-galactosidase activity. Notably, the expression profiles of RUNX1-mutated LR-MDS resembled those of higher-risk MDS at diagnosis. This study demonstrates that incorporating molecular data improves LR-MDS risk stratification and that mutated RUNX1 is associated with a suppressed defense against LR-MDS progression.

DOI: https://doi.org/10.1038/s41375-022-01584-3
Blood Adv. 2022 May 04. pii: bloodadvances.2022007001. [Epub ahead of print]

Overlapping and unique substrate specificities of ST3GAL1 and 2 during hematopoietic and megakaryocytic differentiation.

Nanyan Zhang, Siying Lin, Weiguo Cui, Peter J Newman.

Although the sialyltransferases ST3GAL1 and ST3GAL2 are known to transfer sialic acid to the galactose residue of type III disaccharides (Galβ1,3GalNAc) in vitro, sialylation of O-linked glycosylated proteins in living cells has been largely attributed to ST3GAL1. To examine the role of ST3GAL2 in O-sialylation, we examined its expression during differentiation of human induced pluripotent stem cells (iPSCs) into hematopoietic progenitor cells (HPCs) and megakaryocytes (MKs). ST3GAL1 and ST3GAL2 each became highly expressed during the differentiation of iPSCs to HPCs, but decreased markedly in their expression upon differentiation into megakaryocytes, suggesting coordination of expression during megakaryopoiesis. To further delineate their role in these processes, we generated ST3GAL1-, ST3GAL2-, and doubly-deficient human iPSC lines. Binding of the peanut agglutinin lectin, PNA, which reports the presence of unsialylated Galβ1,3GalNAc glycan chains, was strongly increased in HPCs and MKs derived from double knockout iPSCs, and remained moderately increased in cells lacking either one of these sialyltransferases, demonstrating that both can serve as functional cellular O-glycan sialyltransferases. Interestingly, the HPC markers CD34 and CD43, as well as MK membrane glycoprotein (GP) GPIbα, were identified as major glycoprotein substrates for ST3GAL1 and ST3GAL2. In contrast, O-sialylation of GPIIb relied predominantly on the expression of ST3GAL2. Finally, while disruption of ST3GAL1 and ST3GAL2 had little impact on MK production, their absence resulted in dramatically impaired MK proplatelet formation. Taken together, these data establish heretofore unknown physiological roles for ST3GAL1 and ST3GAL2 in O-linked glycan sialylation in hemato- and megakaryocyto-poiesis.

DOI: https://doi.org/10.1182/bloodadvances.2022007001
Sci Rep. 2022 May 03. 12(1): 7181

CRISPR-Cas9 mediated generation of a conditional poly(A) binding protein nuclear 1 (Pabpn1) mouse model reveals an essential role for hematopoietic stem cells.

Pia Sommerkamp, Alexander C Sommerkamp, Petra Zeisberger, Paula Leonie Eiben, Andreas Narr, Aylin Korkmaz, Adriana Przybylla, Markus Sohn, Franciscus van der Hoeven, Kai Schönig, Andreas Trumpp.

Poly(A) binding protein nuclear 1 (PABPN1) is known for its role in poly(A) tail addition and regulation of poly(A) tail length. In addition, it has been shown to be involved in alternative polyadenylation (APA). APA is a process regulating differential selection of polyadenylation sites, thereby influencing protein isoform expression and 3'-UTR make-up. In this study, we generated an inducible Pabpn1flox/flox mouse model using crRNA-tracrRNA:Cas9 complexes targeting upstream and downstream genomic regions, respectively, in combination with a long single-stranded DNA (ssDNA) template. We performed extensive in vitro testing of various guide RNAs (gRNAs) to optimize recombination efficiency for in vivo application. Pabpn1flox/flox mice were generated and crossed to MxCre mice for validation experiments, allowing the induction of Cre expression in the bone marrow (BM) by poly(I:C) (pIC) injections. Validation experiments revealed successful deletion of Pabpn1 and absence of PABPN1 protein. Functionally, knockout (KO) of Pabpn1 led to a rapid and robust depletion of hematopoietic stem and progenitor cells (HSPCs) as well as myeloid cells, suggesting an essential role of Pabpn1 in the hematopoietic lineage. Overall, the mouse model allows an inducible in-depth in vivo analysis of the role of PABPN1 and APA regulation in different tissues and disease settings.

DOI: https://doi.org/10.1038/s41598-022-11203-x
Cancer Lett. 2022 Apr 28. pii: S0304-3835(22)00194-X. [Epub ahead of print]538 215710

Metabolic reprogramming by ex vivo glutamine inhibition endows CAR-T cells with less-differentiated phenotype and persistent antitumor activity.

Luyan Shen, Yefei Xiao, Chaoting Zhang, Shance Li, Xia Teng, Likun Cui, Ting Liu, Nan Wu, Zheming Lu.

  The inadequate in vivo persistence of chimeric antigen receptor (CAR)-modified T cells has been shown to lead to poor therapeutic efficacy and disease recurrence. In vivo persistence is associated with the differentiation subsets infused, with less differentiated TN or TCM conferring superior renewal capacity and antitumor immunity compared to TEM or TEFF. However, ex vivo expanded CAR-T cells exhibit phenotypic heterogeneity with majority of TEM or TEFF subsets and very low populations of TN and TCM. The transition of differentiation subsets is closely correlated with T cell metabolism fitness. Effector T cell differentiation from TN or TCM requires glutamine uptake and metabolism. Using a CD19-specific CAR, we demonstrated that glutamine inhibition by adding the glutamine antagonist 6-Diazo-5-oxo-l-norleucine (DON) into the culture endows CAR-T cells with enhanced mitochondrial OXPHOS utilizing fatty acids and reduced glycolytic activity, and retains more TN or TCM subsets. DON- pretreated CAR-T cells exhibited stronger cytotoxic lysis in vitro and more robust elimination of tumor burdens in vivo. This study suggests that glutamine inhibition ex vivo would be a potential approach for modulating metabolism and differentiation state to improve the efficacy of CAR-T cell therapy.

Keywords:  Fatty acid oxidation; Glutamine antagonist; Glycolysis; Memory T cell; Mitochondrial OXPHOS

DOI:  https://doi.org/10.1016/j.canlet.2022.215710
JACC CardioOncol. 2022 Mar;4(1): 50-52

Leukemia and Heart Disease: Lessons at the Intersection of the Most Feared CHIP Outcomes.

Philipp J Rauch, Benjamin L Ebert.



Keywords:  acute myeloid leukemia; aging; clonal hematopoiesis; coronary artery disease; inflammation

DOI:  https://doi.org/10.1016/j.jaccao.2022.01.094
Blood. 2022 May 04. pii: blood.2021013648. [Epub ahead of print]

Anti-CCR9 Chimeric Antigen Receptor T cells for T Cell Acute Lymphoblastic Leukemia.

Paul Michael Maciocia, Patrycja A Wawrzyniecka, Nicola C Maciocia, Amy Burley, Thaneswari Karpanasamy, Sam Devereaux, Malika Hoekx, David O'Connor, Theresa Elizabeth Leon, Tanya Rapoz-D'Silva, Rachael Pocock, Sunniyat Rahman, Giuseppe Gritti, Diana C Yánez, Susan Ross, Tessa Crompton, Owen Williams, Lydia Sarah Hui Lee, Martin Pule, Marc R Mansour.

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy of immature T lymphocytes, associated with higher rates of induction failure in comparison to B-ALL. The potent immunotherapeutic approaches applied in B-ALL, which have revolutionized the treatment paradigm, have proven more challenging in T-ALL, largely due to a lack of target antigens expressed on malignant but not healthy T cells. Unlike B cell depletion, T cell aplasia is highly toxic. Here, we demonstrate that the chemokine receptor CCR9 is expressed in >70% of cases of T-ALL, including >85% or relapsed/ refractory disease, and only on a small fraction (<5%) of normal T cells. Using cell line models and patient-derived xenografts, we show chimeric antigen receptor (CAR)-T cells targeting CCR9 are resistant to fratricide and have potent anti-leukemic activity both in vitro and in vivo, even at low target antigen density. We propose anti-CCR9 CAR-T cells could be a highly effective treatment strategy for T-ALL, avoiding T cell aplasia and the need for genome engineering that complicate other approaches.

DOI: https://doi.org/10.1182/blood.2021013648