Supplementary Data 1-5 from Reciprocal Relationship between O6-Methylguanine-DNA Methyltransferase P140K Expression Level and Chemoprotection of Hematopoietic Stem Cells

CAR T cells are genetically modified T cells that target specific epitopes. CAR T cell therapy has proven effective in difficult-to-treat B cell cancers and is now expanding into hematology and solid tumors. To date, approved CAR therapies target only two specific epitopes on cancer cells. Identifying more suitable targets is challenged by the lack of truly cancer-specific structures and the potential for on-target off-tumor toxicity. We analyzed gene expression of potential targets in single-cell data from cancer and healthy tissues. Because safety and efficacy can ultimately only be defined clinically, we selected approved and investigational targets for which clinical trail data are available. We generated atlases using >300,000 cells from 48 patients with follicular lymphoma, multiple myeloma, and B-cell acute lymphoblastic leukemia, and integrated over 3 million cells from 35 healthy tissues, harmonizing datasets from over 300 donors. To contextualize findings, we compared target expression patterns with outcome data from clinical trials, linking target profiles to efficacy and toxicity, and ranked 15 investigational targets based on their similarity to approved ones. Target expression did not significantly correlate with reported clinical toxicities in patients undergoing therapy. This may be attributed to the intricate interplay of patient-specific variables, the limited amount of metadata, and the complexity underlying toxicity. Nevertheless, our study serves as a resource for retrospective and prospective target evaluation to improve the safety and efficacy of CAR therapies.

ABSTRACT:The success of targeted therapies for hematological malignancies has heralded their potential as both salvage treatment and early treatment lines, reducing the need for high-dose, intensive, and often toxic chemotherapeutic regimens. For young patients with classic Hodgkin lymphoma (cHL), immunotherapies provide the possibility to lessen long-term, treatment-related toxicities. However, suitable therapeutic targets are lacking. By integrating single-cell dissection of the tumor landscape and an in-depth, single-cell-based off-tumor antigen prediction, we identify CD86 as a promising therapeutic target in cHL. CD86 is highly expressed on Hodgkin and Reed-Sternberg cancer cells and cHL-specific tumor-associated macrophages. We reveal CD86-CTLA-4 as a key suppressive pathway in cHL, driving T-cell exhaustion. Cellular therapies targeting CD86 had extraordinary efficacy in vitro and in vivo and were safe in immunocompetent mouse models without compromising bacterial host defense in sepsis models. Our results prove the potential value of anti-CD86 immunotherapies for treating cHL.

Embryos from different mammalian species develop at characteristic timescales. These timescales are recapitulated during the differentiation of pluripotent stem cells in vitro. Specific genes and molecular pathways that modulate cell differentiation speed between mammalian species remain to be determined. Here we use single-cell multi-omic analysis of neural differentiation of mouse, cynomolgus and human pluripotent cells to identify regulators for differentiation speed. We demonstrate that species-specific transcriptome dynamics are mirrored at the chromatin level, but that the speed of neural differentiation is insensitive to manipulations of cell growth and cycling. Exploiting the single-cell resolution of our data, we identify glycogen storage levels regulated by UDP-glucose pyrophosphorylase 2 (UGP2) as a species-dependent trait of pluripotent cells, and show that lowered glycogen storage in UGP2 mutant cells is associated with accelerated neural differentiation. The control of energy storage could be a general strategy for the regulation of cell differentiation speed. ### Competing Interest Statement The authors have declared no competing interest.

Acute myeloid leukemia (AML) is characterized by the accumulation of immature myeloid cells in the bone marrow and the peripheral blood. Nearly half of the AML patients relapse after standard induction therapy, and new forms of therapy are urgently needed. Chimeric antigen receptor (CAR) T therapy has so far not been successful in AML due to lack of efficacy and safety. Indeed, the most attractive antigen targets are stem cell markers such as CD33 or CD123. We demonstrate that CD37, a mature B cell marker, is expressed in AML samples, and its presence correlates with the European LeukemiaNet (ELN) 2017 risk stratification. We repurpose the anti -lymphoma CD37CAR for the treatment of AML and show that CD37CAR T cells specifically kill AML cells, secrete proinflammatory cytokines, and control cancer progression in vivo . Importantly, CD37CAR T cells display no toxicity toward hematopoietic stem cells. Thus, CD37 is a promising and safe CAR T cell AML target.

The CRISPR-Cas12a platform has attracted interest in the genome editing community because the prototypical Acidaminococcus Cas12a generates a staggered DNA double-strand break upon binding to an AT-rich protospacer-adjacent motif (PAM, 5′-TTTV). The broad application of the platform in primary human cells was enabled by the development of an engineered version of the natural Cas12a protein, called Cas12a Ultra. In this study, we confirmed that CRISPR-Cas12a Ultra ribonucleoprotein complexes enabled allelic gene disruption frequencies of over 90% at multiple target sites in human T cells, hematopoietic stem and progenitor cells (HSPCs), and induced pluripotent stem cells (iPSCs). In addition, we demonstrated, for the first time, the efficient knock-in potential of the platform in human iPSCs and achieved targeted integration of a GFP marker gene into the AAVS1 safe harbor site and a CSF2RA super-exon into CSF2RA in up to 90% of alleles without selection. Clonal analysis revealed bi-allelic integration in >50% of the screened iPSC clones without compromising their pluripotency and genomic integrity. Thus, in combination with the adeno-associated virus vector system, CRISPR-Cas12a Ultra provides a highly efficient genome editing platform for performing targeted knock-ins in human iPSCs.

Abstract Background The development of the CRISPR-Cas12a platform has generated considerable interest in the genome editing community. Due to its AT-rich protospacer-adjacent motif (PAM, 5’-TTTV), Cas12a increased the potential number of targetable sites for gene editing beyond that of the prototypical Streptococcus pyogenes CRISPR-Cas9 system. Moreover, evaluation of the off-target activity of CRISPR-Cas12a nucleases suggested high specificity of the platform. Broad application of the CRISPR-Cas12a platform in primary human cells was recently enabled by the development of a re-engineered version of the natural Acidaminococcus Cas12a, called Cas12a Ultra. Methods We transferred the CRISPR-Cas12a Ultra system in the form of ribonucleoprotein complexes into clinically relevant human cells, including T cells, multipotent hematopoietic stem and progenitor cells (HSPCs), and induced pluripotent stem cells (iPSCs). Allelic gene editing frequencies were determined at various target sites using standard genotyping and next-generation sequencing. Furthermore, we evaluated targeted integration of transgenes into the AAVS1 safe harbor site and the CSF2RA locus of patient-derived iPSCs. Results We achieved allelic gene disruption frequencies of over 90% at various target sites in multiple primary human cell types. In addition, we demonstrated efficient knock-in of a GFP marker gene into the AAVS1 locus, and achieved targeted integration of a therapeutic DNA template into 90% of CSF2RA alleles in iPSCs without selection. Clonal analysis revealed bi-allelic integration in > 50% of the screened iPSC clones without compromising their pluripotency and genome integrity. Conclusions Herein, we demonstrate that the CRISPR-Cas12a Ultra system provides a highly efficient genome editing platform for human stem cell applications, expanding the toolbox for clinical applications.

BACKGROUND:Macrophages have recently become attractive therapeutics in cancer immunotherapy. The potential of macrophages to infiltrate and influence solid malignancies makes them promising targets for the chimeric antigen receptor (CAR) technology to redirect their stage of polarization, thus enhancing their anticancer capacities. Given the emerging interest for CAR-macrophages, generation of such cells so far mainly depends on peripheral blood monocytes, which are isolated from the respective donor prior to genetic manipulation. This procedure is time-intensive and cost-intensive, while, in some cases, insufficient monocyte amounts can be recovered from the donor, thus hampering the broad applicability of this technology. Hence, we demonstrate the generation and effectiveness of CAR-macrophages from various stem cell sources using also modern upscaling technologies for next generation immune cell farming.METHODS:Primary human hematopoietic stem and progenitor cells and induced pluripotent stem cells were used to derive anti-CD19 CAR-macrophages. Anticancer activity of the cells was demonstrated in co-culture systems, including primary material from patients with leukemia. Generation of CAR-macrophages was facilitated by bioreactor technologies and single-cell RNA (scRNA) sequencing was used to characterize in-depth response and behavior of CAR-macrophages.RESULTS:Irrespective of the stem-cell source, CAR-macrophages exhibited enhanced and antigen-dependent phagocytosis of CD19+ target cancer cells with increased pro-inflammatory responses. Phagocytic capacity of CAR-macrophages was dependent on target cell CD19 expression levels with superior function of CAR-macrophages against CD19+ cancer cell lines and patient-derived acute lymphocytic leukemia cancer cells. scRNA sequencing revealed CAR-macrophages to be distinct from eGFP control cells after co-culture with target cells, which includes the activation of pro-inflammatory pathways and upregulation of chemokines and cytokines associated with adaptive immune cell recruitment, favoring the repolarization of CAR-macrophages to a pro-inflammatory state. Taken together, the data highlight the unique features of CAR-macrophages in combination with the successful upscaling of the production pipeline using a three-dimensional differentiation protocol and intermediate scale bioreactors.CONCLUSION:In summary, our work provides insights into the seminal use and behavior of CAR-macrophages which are derived from various sources of stem cells, while introducing a unique technology for CAR-macrophage manufacturing, all dedicated to the clinical translation of CAR-macrophages within the field of anticancer immunotherapies.

Chimeric antigen receptor T cells (CAR-T cells) have emerged as a powerful treatment option for individuals with B cell malignancies but have yet to achieve success in treating acute myeloid leukemia (AML) due to a lack of safe targets. Here we leveraged an atlas of publicly available RNA-sequencing data of over 500,000 single cells from 15 individuals with AML and tissue from 9 healthy individuals for prediction of target antigens that are expressed on malignant cells but lacking on healthy cells, including T cells. Aided by this high-resolution, single-cell expression approach, we computationally identify colony-stimulating factor 1 receptor and cluster of differentiation 86 as targets for CAR-T cell therapy in AML. Functional validation of these established CAR-T cells shows robust in vitro and in vivo efficacy in cell line- and human-derived AML models with minimal off-target toxicity toward relevant healthy human tissues. This provides a strong rationale for further clinical development.

Severe congenital neutropenia (CN) is a pre-leukemic bone marrow failure syndrome that can evolve to acute myeloid leukemia (AML). Mutations in CSF3R and RUNX1 are frequently observed in CN patients, although how they drive the transition from CN to AML (CN/AML) is unclear. Here we establish a model of stepwise leukemogenesis in CN/AML using CRISPR-Cas9 gene editing of CN patient-derived iPSCs. We identified BAALC upregulation and resultant phosphorylation of MK2a as a key leukemogenic event. BAALC deletion or treatment with CMPD1, a selective inhibitor of MK2a phosphorylation, blocked proliferation and induced differentiation of primary CN/AML blasts and CN/AML iPSC-derived hematopoietic stem and progenitor cells (HSPCs) without affecting healthy donor or CN iPSC-derived HSPCs. Beyond detailing a useful method for future investigation of stepwise leukemogenesis, this study suggests that targeting BAALC and/or MK2a phosphorylation may prevent leukemogenic transformation or eliminate AML blasts in CN/AML and RUNX1 mutant BAALC(hi) de novo AML.

Background Melanoma is an immune sensitive disease, as demonstrated by the activity of immune check point blockade (ICB), but many patients will either not respond or relapse. More recently, tumor infiltrating lymphocyte (TIL) therapy has shown promising efficacy in melanoma treatment after ICB failure, indicating the potential of cellular therapies. However, TIL treatment comes with manufacturing limitations, product heterogeneity, as well as toxicity problems, due to the transfer of a large number of phenotypically diverse T cells. To overcome said limitations, we propose a controlled adoptive cell therapy approach, where T cells are armed with synthetic agonistic receptors (SAR) that are selectively activated by bispecific antibodies (BiAb) targeting SAR and melanoma-associated antigens.Methods Human as well as murine SAR constructs were generated and transduced into primary T cells. The approach was validated in murine, human and patient-derived cancer models expressing the melanoma-associated target antigens tyrosinase-related protein 1 (TYRP1) and melanoma-associated chondroitin sulfate proteoglycan (MCSP) (CSPG4). SAR T cells were functionally characterized by assessing their specific stimulation and proliferation, as well as their tumor-directed cytotoxicity, in vitro and in vivo.Results MCSP and TYRP1 expression was conserved in samples of patients with treated as well as untreated melanoma, supporting their use as melanoma-target antigens. The presence of target cells and anti-TYRP1 × anti-SAR or anti-MCSP × anti-SAR BiAb induced conditional antigen-dependent activation, proliferation of SAR T cells and targeted tumor cell lysis in all tested models. In vivo, antitumoral activity and long-term survival was mediated by the co-administration of SAR T cells and BiAb in a syngeneic tumor model and was further validated in several xenograft models, including a patient-derived xenograft model.Conclusion The SAR T cell-BiAb approach delivers specific and conditional T cell activation as well as targeted tumor cell lysis in melanoma models. Modularity is a key feature for targeting melanoma and is fundamental towards personalized immunotherapies encompassing cancer heterogeneity. Because antigen expression may vary in primary melanoma tissues, we propose that a dual approach targeting two tumor-associated antigens, either simultaneously or sequentially, could avoid issues of antigen heterogeneity and deliver therapeutic benefit to patients.

Abstract Background The development of the CRISPR-Cas12a platform has generated considerable interest in the genome editing community. Due to its AT-rich protospacer-adjacent motif (PAM, 5’-TTTV), Cas12a increased the potential number of targetable sites for gene editing beyond that of the prototypical Streptococcus pyogenes CRISPR-Cas9 system. Moreover, evaluation of the off-target activity of CRISPR-Cas12a nucleases suggested high specificity of the platform. Broad application of the CRISPR-Cas12a platform in primary human cells was recently enabled by the development of a re-engineered version of the natural Acidaminococcus Cas12a, called Cas12a Ultra. Methods We transferred the CRISPR-Cas12a Ultra system in the form of ribonucleoprotein complexes into clinically relevant human cells, including T cells, multipotent hematopoietic stem and progenitor cells (HSPCs), and induced pluripotent stem cells (iPSCs). Allelic gene editing frequencies were determined at various target sites using standard genotyping and next-generation sequencing. Furthermore, we evaluated targeted integration of transgenes into the AAVS1 safe harbor site and the CSF2RA locus of patient-derived iPSCs. Results We achieved allelic gene disruption frequencies of over 90% at various target sites in multiple primary human cell types. In addition, we demonstrated efficient knock-in of a GFP marker gene into the AAVS1 locus, and achieved targeted integration of a therapeutic DNA template into 90% of CSF2RA alleles in iPSCs without selection. Clonal analysis revealed bi-allelic integration in > 50% of the screened iPSC clones without compromising their pluripotency and genome integrity. Conclusions Herein, we demonstrate that the CRISPR-Cas12a Ultra system provides a highly efficient genome editing platform for human stem cell applications, expanding the toolbox for clinical applications.

Platelets are anucleate blood cells that are shed from megakaryocytes (MKs) into the bloodstream to maintain hemostasis and promote wound healing after vascular injury. To carry out their functions, platelets become activated and release bioactive substances from their secretory granules. As alpha granules (αGs) in resting platelets store proteins and release them only after activation, the packaging of proteins into αGs is an attractive strategy to deliver therapeutic proteins. Here, we propose an adjustable model for targeting transgenic proteins to platelet αGs using third-generation self-inactivating lentiviral vectors. The vectors express from the murine platelet factor 4 promoter (mPf4P), restricting transgene expression to the MK lineage. For the delivery and retention of expressed proteins in αGs, proteins are fused to short peptide sorting signals derived from the human cytokine RANTES or from the transmembrane protein P-selectin. We demonstrate effective targeting of GFP to αGs of murine and human in vitro-differentiated MKs and murine platelets in vivo. Furthermore, interferon-α (IFNα), as a potentially therapeutic cytokine, was successfully delivered to and stored in murine platelets in vivo, was released after activation, and inhibited virus replication in vitro. Our vectors create possibilities for numerous applications in cell therapy utilizing platelets as carriers of therapeutic proteins.

Clonal hematopoiesis of indeterminate potential (CHIP) increases the risk to develop hematological cancers such as acute myeloid leukemia (AML) tenfold. Since AML has been shown to originate from a hematopoietic stem/progenitor cell (HSPC) we compared the transcriptional landscape of bone marrow HSPCs from a healthy donor and a CHIP carrier (mutations in DNMT3A, 1.1% VAF and TET2, 5.3% VAF) by performing single cell RNA and ATAC sequencing. Cell frequency analysis of HSCP subpopulations, defined by analysis of conserved genes in clusters after dimensional reduction, showed that the proportion of HSC was twofold higher in the CHIP donor whereas the lymphocyte progenitor and pre-B cells compartment was fourfold lower, indicating an overall myeloid bias in the CHIP donor. Gene Ontology analysis of differentially expressed genes in the HSC compartment showed an upregulation of genes involved in metabolic processes in CHIP HSCs, among which genes that are associated with the onset of AML such as MEIS1 and PBX1. Furthermore, the expression levels of genes that are involved in niche retention, such as CD44 and VLA-4 were significantly higher in CHIP HSCs, suggesting alterations in the architecture of CHIP bone marrow. In addition to differences in gene expression, chromatin accessibility analysis showed unique genomic peaks in the CHIP HSC. Analysis of these sequences for binding motifs of transcription factors showed an overabundance of GATA, CEBP and RUNX1 motifs, all believed to play major roles in the onset of AML. The transcriptional landscapes of HSPC from healthy and CHIP donors show distinct differences, indicating that even the absence of signs of hematological disease, changes associated with a possible onset of malignancy can already be observed and provide possible targets for early intervention. Clonal hematopoiesis of indeterminate potential (CHIP) increases the risk to develop hematological cancers such as acute myeloid leukemia (AML) tenfold. Since AML has been shown to originate from a hematopoietic stem/progenitor cell (HSPC) we compared the transcriptional landscape of bone marrow HSPCs from a healthy donor and a CHIP carrier (mutations in DNMT3A, 1.1% VAF and TET2, 5.3% VAF) by performing single cell RNA and ATAC sequencing. Cell frequency analysis of HSCP subpopulations, defined by analysis of conserved genes in clusters after dimensional reduction, showed that the proportion of HSC was twofold higher in the CHIP donor whereas the lymphocyte progenitor and pre-B cells compartment was fourfold lower, indicating an overall myeloid bias in the CHIP donor. Gene Ontology analysis of differentially expressed genes in the HSC compartment showed an upregulation of genes involved in metabolic processes in CHIP HSCs, among which genes that are associated with the onset of AML such as MEIS1 and PBX1. Furthermore, the expression levels of genes that are involved in niche retention, such as CD44 and VLA-4 were significantly higher in CHIP HSCs, suggesting alterations in the architecture of CHIP bone marrow. In addition to differences in gene expression, chromatin accessibility analysis showed unique genomic peaks in the CHIP HSC. Analysis of these sequences for binding motifs of transcription factors showed an overabundance of GATA, CEBP and RUNX1 motifs, all believed to play major roles in the onset of AML. The transcriptional landscapes of HSPC from healthy and CHIP donors show distinct differences, indicating that even the absence of signs of hematological disease, changes associated with a possible onset of malignancy can already be observed and provide possible targets for early intervention.

Chimeric antigen receptor (CAR)-engineered T cells can be highly effective in the treatment of hematological malignancies, but mostly fail in the treatment of solid tumors. Thus, approaches using 4 th advanced CAR T cells secreting immunomodulatory cytokines upon CAR signaling, known as TRUCKs (“ T cells redirected for universal cytokine-mediated killing ”), are currently under investigation. Based on our previous development and validation of automated and closed processing for GMP-compliant manufacturing of CAR T cells, we here present the proof of feasibility for translation of this method to TRUCKs. We generated IL-18-secreting TRUCKs targeting the tumor antigen GD 2 using the CliniMACS Prodigy ® system using a recently described “all-in-one” lentiviral vector combining constitutive anti-GD 2 CAR expression and inducible IL-18. Starting with 0.84 x 10 8 and 0.91 x 10 8 T cells after enrichment of CD4 + and CD8 + we reached 68.3-fold and 71.4-fold T cell expansion rates, respectively, in two independent runs. Transduction efficiencies of 77.7% and 55.1% was obtained, and yields of 4.5 x 10 9 and 3.6 x 10 9 engineered T cells from the two donors, respectively, within 12 days. Preclinical characterization demonstrated antigen-specific GD 2 -CAR mediated activation after co-cultivation with GD 2 -expressing target cells. The functional capacities of the clinical-scale manufactured TRUCKs were similar to TRUCKs generated in laboratory-scale and were not impeded by cryopreservation. IL-18 TRUCKs were activated in an antigen-specific manner by co-cultivation with GD 2 -expressing target cells indicated by an increased expression of activation markers (e.g. CD25, CD69) on both CD4 + and CD8 + T cells and an enhanced release of pro-inflammatory cytokines and cytolytic mediators (e.g. IL-2, granzyme B, IFN-γ, perforin, TNF-α). Manufactured TRUCKs showed a specific cytotoxicity towards GD 2 -expressing target cells indicated by lactate dehydrogenase (LDH) release, a decrease of target cell numbers, microscopic detection of cytotoxic clusters and detachment of target cells in real-time impedance measurements (xCELLigence). Following antigen-specific CAR activation of TRUCKs, CAR-triggered release IL-18 was induced, and the cytokine was biologically active, as demonstrated in migration assays revealing specific attraction of monocytes and NK cells by supernatants of TRUCKs co-cultured with GD 2 -expressing target cells. In conclusion, GMP-compliant manufacturing of TRUCKs is feasible and delivers high quality T cell products.

OBJECTIVE:Pancreatic islets of Langerhans secrete hormones to regulate systemic glucose levels. Emerging evidence suggests that islet cells are functionally heterogeneous to allow a fine-tuned and efficient endocrine response to physiological changes. A precise description of the molecular basis of this heterogeneity, in particular linking animal models to human islets, is an important step towards identifying the factors critical for endocrine cell function in physiological and pathophysiological conditions.METHODS:In this study, we used single-cell RNA sequencing to profile more than 50'000 endocrine cells isolated from healthy human, pig and mouse pancreatic islets and characterize transcriptional heterogeneity and evolutionary conservation of those cells across the three species. We systematically delineated endocrine cell types and α- and β-cell heterogeneity through prior knowledge- and data-driven gene sets shared across species, which altogether capture common and differential cellular properties, transcriptional dynamics and putative driving factors of state transitions.RESULTS:We showed that global endocrine expression profiles correlate, and that critical identity and functional markers are shared between species, while only approximately 20% of cell type enriched expression is conserved. We resolved distinct human α- and β-cell states that form continuous transcriptional landscapes. These states differentially activate maturation and hormone secretion programs, which are related to regulatory hormone receptor expression, signaling pathways and different types of cellular stress responses. Finally, we mapped mouse and pig cells to the human reference and observed that the spectrum of human α- and β-cell heterogeneity and aspects of such functional gene expression are better recapitulated in the pig than mouse data.CONCLUSIONS:Here, we provide a high-resolution transcriptional map of healthy human islet cells and their murine and porcine counterparts, which is easily queryable via an online interface. This comprehensive resource informs future efforts that focus on pancreatic endocrine function, failure and regeneration, and enables to assess molecular conservation in islet biology across species for translational purposes.

Metastatic disease is the leading cause of death in children suffering from medulloblastoma and a major treatment challenge. The evidence of leptomeningeal dissemination defines the most aggressive tumours and is associated with increased mortality; thus, inhibition of migration as a factor involved in the process of metastatic disease is fundamental for the treatment and prevention of metastatic dissemination. Targeting the small Rho GTPases Rac1 has been shown to effectively impair medulloblastoma cell migration in vitro. Yet clinically applicable selective Rac1 inhibitors are still lacking. In view of the pertinent oncogenic role of the PI3K signalling cascade and tyrosine kinase-mediated signalling pathways in medulloblastoma, we explored clinically available targeted therapeutics to this effect. Here, we show that Rac1 is expressed in both the cytoplasm and nucleus in the medulloblastoma cell lines Daoy and MEB-Med-8A representative of two high risk medulloblastoma entities. We demonstrate that activated Rac1 is subject to substantial downmodulation following administration of the clinically available inhibitor of the PI3K pathway Pictilisib (GDC-0941) and the multityrosine kinase inhibitors Pazopanib and Sorafenib. The application of those drugs was associated with reduced mobility of the medulloblastoma cells and alterations of the actin skeleton. Of note, PI3K inhibition reveals the strongest anti-migratory effect in Daoy cells. Thus, our in vitro observations provide new insights into different strategies of blocking Rac1 and inhibiting migration in medulloblastoma employing clinically available agents paving the way for confirmatory studies in in vivo models.

Chimeric antigen receptor (CAR) T-cell therapies have shown impressive results in patients with hematological malignancies; however, little success has been achieved in the treatment of solid tumors. Recently, macrophages (MΦs) were identified as an additional candidate for the CAR approach, and initial proof of concept studies using peripheral blood-derived monocytes showed antigen-redirected activation of CAR MΦs. However, some patients may not be suitable for monocyte-apheresis, and prior cancer treatment regimens may negatively affect immune cell number and functionality. To address this problem, we here introduce primary human hematopoietic stem and progenitor cells (HSPCs) as a cell source to generate functional CAR MΦs ex vivo. Our data showed successful CAR expression in cord blood (CB)-derived HSPCs, with considerable cell expansion during differentiation to CAR MΦs. HSPC-derived MΦs showed typical MΦ morphology, phenotype, and basic anti-bacterial functionality. CAR MΦs targeting the carcinoembryonic antigen (CEA) and containing either a DAP12- or a CD3ζ-derived signaling domain showed antigen redirected activation as they secreted pro-inflammatory cytokines specifically upon contact with CEA+ target cells. In addition, CD3ζ-expressing CAR MΦs exhibited significantly enhanced phagocytosis of CEA+ HT1080 cells. Our data establish human HSPCs as a suitable cell source to generate functional CAR MΦs and further support the use of CAR MΦs in the context of solid tumor therapy.