Leukemias with NUP98 rearrangements exhibit heterogeneous phenotypes correlated to fusion partners, whereas the mechanism responsible for this heterogeneity is poorly understood. Through genome-wide mutational and transcriptional analyses of 177 NUP98 -rearranged leukemias, we show that cooperating alterations are associated with differentiation status even among leukemias sharing the same NUP98 fusions, such as NUP98::KDM5A acute megakaryocytic leukemia with RB1 loss or T-cell acute lymphoblastic leukemia with NOTCH1 mutations. CUT&RUN profiling reveals that NUP98 fusion oncoproteins directly regulate differentiation-related genes, with binding patterns also influenced by differentiation stage. Using in vitro models, we show RB1 loss cooperates with NUP98::KDM5A by blocking terminal differentiation toward platelets and expanding megakaryocyte-like cells, whereas WT1 frameshifts skew differentiation toward dormant lympho-myeloid primed progenitor cells and cycling granulocyte-monocyte progenitor cells. NUP98::KDM5A models with RB1 or WT1 alterations have different sensitivities to menin inhibition, suggesting cellular differentiation stage-specific resistant mechanism against menin inhibitors with clinical implications for NUP98 -rearranged leukemia.

Intermediate-length repeat expansions in ATAXIN-2 (ATXN2) are the strongest genetic risk factor for amyotrophic lateral sclerosis (ALS). At the molecular level, ATXN2 intermediate expansions enhance TDP-43 toxicity and pathology. However, whether this triggers ALS pathogenesis at the cellular and functional level remains unknown. Here, we combine patient-derived and mouse models to dissect the effects of ATXN2 intermediate expansions in an ALS background. iPSC-derived motor neurons from ATXN2-ALS patients show altered stress granules, neurite damage and abnormal electrophysiological properties compared to healthy control and other familial ALS mutations. In TDP-43Tg-ALS mice, ATXN2-Q33 causes reduced motor function, NMJ alterations, neuron degeneration and altered in vitro stress granule dynamics. Furthermore, gene expression changes related to mitochondrial function and inflammatory response are detected and confirmed at the cellular level in mice and human neuron and organoid models. Together, these results define pathogenic defects underlying ATXN2-ALS and provide a framework for future research into ATXN2-dependent pathogenesis and therapy.
© 2024. The Author(s).

Abstract Tumor evolution is one of the major mechanisms responsible for acquiring therapy-resistant and more aggressive cancer clones. Whether the tumor microenvironment through immune-mediated mechanisms might promote the development of more aggressive cancer types is crucial for the identification of additional therapeutical opportunities. Here, we identified a novel subset of tumor-associated neutrophils, defined as tumor-associated neutrophil precursors (PreNeu). These PreNeu are enriched in highly proliferative hormone-dependent breast cancers and impair DNA repair capacity.  Mechanistically, succinate secreted by tumor-associated PreNeu inhibits homologous recombination, promoting error-prone DNA repair through non-homologous end-joining regulated by PARP-1. Consequently, breast cancer cells acquire genomic instability, promoting tumor editing and progression. Selective inhibition of these pathways induces increased tumor cell killing in vitro and in vivo. Tumor-associated PreNeu score correlates with copy number alterations in highly proliferative hormone-dependent tumors from breast cancer patients. Treatment with PARP-1 inhibitors counteract the pro-tumorigenic effect of these neutrophils and synergize with combined immunotherapeutic approaches.

Glioblastoma (GBM) is an aggressive brain tumor giving a poor prognosis with the current treatment options. The advent of chimeric antigen receptor (CAR) T-cell therapy revolutionized the field of immunotherapy and has provided a new set of therapeutic options for refractory blood cancers. In an effort to apply this therapeutic approach to solid tumors, various immune cell types and CAR constructs are being studied. Notably, macrophages have recently emerged as potential candidates for targeting solid tumors, attributed to their inherent tumor-infiltrating capacity and abundant presence in the tumor microenvironment.
In this study, we developed a chemically defined differentiation protocol to generate macrophages from human pluripotent stem cells (hPSCs). A GBM-specific CAR was genetically incorporated into hPSCs to generate CAR hPSC-derived macrophages.
The CAR hPSC-derived macrophages exhibited potent anticancer activity against GBM cells in vitro.
Our findings demonstrate the feasibility of generating functional CAR-macrophages from hPSCs for adoptive immunotherapy, thereby opening new avenues for the treatment of solid tumors, particularly GBM.
© 2023 The Author(s).

Mesenchymal stem cells (MSCs) possess potent immunomodulatory activity and have been extensively investigated for their therapeutic potential in treating inflammatory disorders. However, the mechanisms underlying the immunosuppressive function of MSCs are not fully understood, hindering the development of standardized MSC-based therapies for clinical use. In this study, we profile the single-cell transcriptomes of MSCs isolated from adipose tissue (AD), bone marrow (BM), placental chorionic membrane (PM), and umbilical cord (UC). Our results demonstrate that MSCs undergo a progressive aging process and that the cellular senescence state influences their immunosuppressive activity by downregulating PD-L1 expression. Through integrated analysis of single-cell transcriptomic and proteomic data, we identify GATA2 as a regulator of MSC senescence and PD-L1 expression. Overall, our findings highlight the roles of cell aging and PD-L1 expression in modulating the immunosuppressive efficacy of MSCs and implicating perinatal MSC therapy for clinical applications in inflammatory disorders.
© 2023. The Author(s).