Management of adult patients with CMML undergoing allo-HCT: recommendations from the EBMT PH&G Committee.

ABSTRACT: Chronic myelomonocytic leukemia (CMML) is a heterogeneous disease presenting with either myeloproliferative or myelodysplastic features. Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only potentially curative option, but the inherent toxicity of this procedure makes the decision to proceed to allo-HCT challenging, particularly because patients with CMML are mostly older and comorbid. Therefore, the decision between a nonintensive treatment approach and allo-HCT represents a delicate balance, especially because prospective randomized studies are lacking and retrospective data in the literature are conflicting. International consensus on the selection of patients and the ideal timing of allo-HCT, specifically in CMML, could not be reached in international recommendations published 6 years ago. Since then, new, CMML-specific data have been published. The European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonization and Guidelines (PH&G) Committee assembled a panel of experts in the field to provide the first best practice recommendations on the role of allo-HCT specifically in CMML. Recommendations were based on the results of an international survey, a comprehensive review of the literature, and expert opinions on the subject, after structured discussion and circulation of recommendations. Algorithms for patient selection, timing of allo-HCT during the course of the disease, pretransplant strategies, allo-HCT modality, as well as posttransplant management for patients with CMML were outlined. The keynote message is, that once a patient has been identified as a transplant candidate, upfront transplantation without prior disease-modifying treatment is preferred to maximize chances of reaching allo-HCT whenever possible, irrespective of bone marrow blast counts.

STIM2 is involved in the regulation of apoptosis and the cell cycle in normal and malignant monocytic cells.

Calcium is a ubiquitous messenger that regulates a wide range of cellular functions, but its involvement in the pathophysiology of acute myeloid leukemia (AML) is not widely investigated. Here, we identified, from an analysis of The Cancer Genome Atlas and genotype-tissue expression databases, stromal interaction molecule 2 (STIM2) as being highly expressed in AML with monocytic differentiation and negatively correlated with overall survival. This was confirmed on a validation cohort of 407 AML patients. We then investigated the role of STIM2 in cell proliferation, differentiation, and survival in two leukemic cell lines with monocytic potential and in normal hematopoietic stem cells. STIM2 expression increased at the RNA and protein levels upon monocyte differentiation. Phenotypically, STIM2 knockdown drastically inhibited cell proliferation and induced genomic stress with DNA double-strand breaks, as shown by increased levels of phosphorylate histone H2AXγ (p-H2AXγ), followed by activation of the cellular tumor antigen p53 pathway, decreased expression of cell cycle regulators such as cyclin-dependent kinase 1 (CDK1)-cyclin B1 and M-phase inducer phosphatase 3 (CDC25c), and a decreased apoptosis threshold with a low antiapoptotic/proapoptotic protein ratio. Our study reports STIM2 as a new actor regulating genomic stability and p53 response in terms of cell cycle and apoptosis of human normal and malignant monocytic cells.

Multi-target measurable residual disease assessed by error-corrected sequencing in patients with acute myeloid leukemia: An ALFA study.

The evaluation of measurable residual disease (MRD) in acute myeloid leukemia (AML) using comprehensive mutation analysis by next-generation sequencing (NGS) has been investigated in several studies. However controversial results exist regarding the detection of persisting mutations in DNMT3A, TET2, and ASXL1 (DTA). Benchmarking of NGS-MRD taking into account other molecular MRD strategies has to be done. Here, we performed error-corrected-NGS-MRD in 189 patients homogeneously treated in the ALFA-0702 study (NCT00932412). Persistence of non-DTA mutations (HR = 2.23 for RFS and 2.26 for OS), and DTA mutations (HR = 2.16 for OS) were associated with poorer prognosis in multivariate analysis. Persistence of at least two mutations in complete remission (CR) was associated with a higher cumulative incidence of relapse (CIR) (HR = 3.71, p < 0.0001), lower RFS (HR = 3.36, p < 0.0001) and OS (HR = 3.81, p = 0.00023) whereas persistence of only one mutation was not. In 100 analyzable patients, WT1-MRD, but not NGS-MRD, was an independent factor for RFS and OS. In the subset of 67 NPM1 mutated patients, both NPM1 mutation detection (p = 0.0059) and NGS-MRD (p = 0.035) status were associated with CIR. We conclude that detectable NGS-MRD including DTA mutations correlates with unfavorable prognosis in AML. Its integration with alternative MRD strategies in AML management warrants further investigations.

PitViper: a software for comparative meta-analysis and annotation of functional screening data.

Recent advancements in shRNA and Cas protein technologies have enabled functional screening methods targeting genes or non-coding regions using single or pooled shRNA and sgRNA. CRISPR-based systems have also been developed for modulating DNA accessibility, resulting in CRISPR-mediated interference (CRISPRi) or activation (CRISPRa) of targeted genes or genomic DNA elements. However, there is still a lack of software tools for integrating diverse array of functional genomics screening outputs that could offer a cohesive framework for comprehensive data integration. Here, we developed PitViper, a flexible and interactive open-source software designed to fill this gap, providing reliable results for the type of elements being screened. It is an end-to-end automated and reproducible bioinformatics pipeline integrating gold-standard methods for functional screening analysis. Our sensitivity analyses demonstrate that PitViper is a useful tool for identifying potential super-enhancer liabilities in a leukemia cell line through genome-wide CRISPRi-based screening. It offers a robust, flexible, and interactive solution for integrating data analysis and reanalysis from functional screening methods, making it a valuable resource for researchers in the field.

Targeting a lineage-specific PI3KÉ£-Akt signaling module in acute myeloid leukemia using a heterobifunctional degrader molecule.

Dose-limiting toxicity poses a major limitation to the clinical utility of targeted cancer therapies, often arising from target engagement in nonmalignant tissues. This obstacle can be minimized by targeting cancer dependencies driven by proteins with tissue-restricted and/or tumor-restricted expression. In line with another recent report, we show here that, in acute myeloid leukemia (AML), suppression of the myeloid-restricted PIK3CG/p110γ-PIK3R5/p101 axis inhibits protein kinase B/Akt signaling and compromises AML cell fitness. Furthermore, silencing the genes encoding PIK3CG/p110γ or PIK3R5/p101 sensitizes AML cells to established AML therapies. Importantly, we find that existing small-molecule inhibitors against PIK3CG are insufficient to achieve a sustained long-term antileukemic effect. To address this concern, we developed a proteolysis-targeting chimera (PROTAC) heterobifunctional molecule that specifically degrades PIK3CG and potently suppresses AML progression alone and in combination with venetoclax in human AML cell lines, primary samples from patients with AML and syngeneic mouse models.