Scalable generation of functional human iPSC-derived CAR-macrophages that efficiently eradicate CD19-positive leukemia

Cancer stem cells and tumor-associated macrophages: Interactions and therapeutic opportunities

Cancer stem cells (CSCs) depend on the tumor microenvironment (TME) to sustain their stem-like properties by recruiting monocytes and reprogramming them into tumor-associated macrophages (TAMs), which in turn promote tumor progression. This review explores CSC-TAM interactions, emphasizing how CSCs drive monocyte recruitment and TAM polarization. We discuss how TAMs enhance CSC stemness and niche maintenance through chemokines, cytokines, exosome-mediated miRNA transfer, direct interactions, and extracellular matrix (ECM) remodeling. Furthermore, we examine therapeutic strategies targeting TAMs, including inhibiting TAM differentiation, reprogramming TAM polarization, and leveraging immune checkpoint blockade and CAR-macrophage immunotherapy to improve cancer treatment outcomes.

Fibroblast-Derived Human iPSC Exhibits Superior Haematopoietic Potential over Human ESC during Haematopoietic Differentiation

Haematopoietic stem cells (HSC) and macrophages hold promise for cell-based therapy. Induced pluripotent stem cells (iPSC) offer an alternative to human embryonic stem cells (hESC) for generating haematopoietic cells in vitro, sidestepping ethical concerns. However, precise comparisons of the developmental process and productivity between iPSC and hESC during haematopoietic differentiation are limited, and producing sufficient HSC for clinical use remains challenging. We introduce a refined, simplified protocol that is xeno-, serum-, and feeder-free for differentiating fibroblast-derived human iPSC (NHDF-iPSC) and the hESC-H9 clone (H9-ESC) using the STEMdiff™ Hematopoietic kit, with differentiation extended by in-house cytokine addition. We demonstrate that NHDF-iPSC recapitulate the haematopoietic differentiation of H9-ESC, forming CD31+CD144+CD34+ haemogenic endothelia (HE) as intermediates, and producing CD34+CD43+CD45+/- haematopoietic stem and progenitor cells (HSPC). This protocol facilitates the production of CD34+ HSPC over an extended period and enhances the yield of HSC from NHDF-iPSC-derived HE three-fold. Interestingly, our results demonstrated that NHDF-iPSC outperformed H9-ESC by exhibiting superior differentiation capabilities, resulting in a higher abundance of HE and greater haematopoietic cell output (e.g., HSPC and HSC) upon cytokine stimulation. This phenomenon is presumably due to the higher expression of RUNX1 in NHDF-iPSC-derived HE (three-fold) as observed in our study, which may lead to a more productive endothelial-to-haematopoietic transition process and potentially facilitate the efficient production of haematopoietic cells. These CD34+ haematopoietic cells mature into 25F9+CD45+ macrophages, which exhibit comparable functions to those derived from hESC. Together, our results underscore the potential of iPSCs as a sustainable source for deriving HSC and macrophages for cell-based therapies.

Targeting myeloid cells for hematological malignancies: the present and future

Hematological malignancies are a diverse group of cancers that originate in the blood and bone marrow and are characterized by the abnormal proliferation and differentiation of hematopoietic cells. Myeloid blasts, which are derived from normal myeloid progenitors, play a central role in these diseases by disrupting hematopoiesis and driving disease progression. In addition, other myeloid cells, including tumor-associated macrophages and myeloid-derived suppressor cells, adapt dynamically to the tumor microenvironment, where they can promote immune evasion and resistance to treatment. This review explores the unique characteristics and pathogenic mechanisms of myeloid blasts, the immunosuppressive roles of myeloid cells, and their complex interactions within the TME. Furthermore, we highlight emerging therapeutic approaches targeting myeloid cells, focusing on strategies to reprogram their functions, inhibit their suppressive effects, or eliminate pathological populations altogether, as well as the latest preclinical and clinical trials advancing these approaches. By integrating insights from these studies, we aim to provide a comprehensive understanding of the roles of myeloid cells in hematological malignancies and their potential as therapeutic targets.

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

Harnessing myeloid cells in cancer

Cancer-associated myeloid cells due to their plasticity play dual roles in both promoting and inhibiting tumor progression. Myeloid cells with immunosuppressive properties play a critical role in anti-cancer immune regulation. Cells of different origin, such as tumor associated macrophages (TAMs), tumor associated neutrophils (TANs), myeloid derived suppressor cells (also called MDSCs) and eosinophils are often expanded in cancer patients and significantly influence their survival, but also the outcome of anti-cancer therapies. For this reason, the variety of preclinical and clinical studies to modulate the activity of these cells have been conducted, however without successful outcome to date. In this review, pro-tumor activity of myeloid cells, myeloid cell-specific therapeutic targets, in vivo studies on myeloid cell re-polarization and the impact of myeloid cells on immunotherapies/genetic engineering are addressed. This paper also summarizes ongoing clinical trials and the concept of chimeric antigen receptor macrophage (CAR-M) therapies, and suggests future research perspectives, offering new opportunities in the development of novel clinical treatment strategies.

Ultrasound-triggered drug release in vivo from antibubble-loaded macrophages

Nanoparticles have proven to be attractive carriers in therapeutic drug delivery since they can encapsulate, protect and stabilize a plethora of different drugs, thereby improving therapeutic efficacy and reducing side effects. However, specific targeting of drug-loaded nanoparticles to the tissue of interest and a timely and spatially controlled release of drugs on demand still represent a challenge. Recently, gas-filled microparticles, so-called antibubbles, have been developed which can efficiently encapsulate liquid drug droplets. Here, we show that antibubbles are efficiently taken up by macrophages in vitro and are stably maintained for more than 48 h without compromising antibubble integrity and macrophage viability. We show that application of diagnostic ultrasound induces the disintegration of both antibubbles and carrier cells while not affecting non-loaded macrophages. Using 4-hydroxytamoxifen as a model drug, we show ultrasound-mediated drug release upon adoptive transfer of antibubble-loaded macrophages in mice. Together with the ability of macrophages to accumulate in inflamed tissues, antibubble-loaded macrophages represent an attractive tool for targeted delivery of drugs and its ultrasound-mediated spatial and temporal drug release, highlighting the therapeutic perspective of this strategy.

Adoptive Cell Therapy from the Dish: Potentiating Induced Pluripotent Stem Cells

Background

The clinical success of autologous adoptive cell therapy (ACT) is substantial but wide application is challenged by the quality and quantity of the patient's immune cells and the need for personalized manufacturing processes. Induced pluripotent stem cells (iPSCs) can be differentiated into immune effectors and thus provide an alternative, allogeneic cell source for ACT. Here, we compare iPSC-derived immune effectors to their PBMC-derived counterparts and review iPSC-derived ACT products currently under preclinical and clinical development.

Summary

iPSC-derived T cells, NK cells, macrophages, and neutrophils largely mimic their PBMC-derived counterparts in terms of cell-surface marker expression and cytotoxic effector functions. iPSC-derived immune effectors can be engineered with chimeric antigen receptors and other activating receptors to redirect their cytotoxic potential specifically to tumor-associated antigens (TAAs). However, several differences between iPSC- and PBMC-derived immune effectors remain and have inspired additional engineering strategies to enhance the antitumor capacity of iPSC-derived immune effectors.

Key Messages

iPSCs can be engineered to facilitate the generation of immune effectors with homogenous specificity for TAAs and enhanced effector functions. TAA-specific and functionally enhanced iPSC-derived T and NK cells are currently undergoing clinical evaluation in phase 1 trials. Engineered iPSC-derived macrophages and neutrophils are in preclinical development.

iPSC Technology Revolutionizes CAR-T Cell Therapy for Cancer Treatment

Chimeric Antigen Receptor (CAR)-engineered T (CAR-T) cell therapy represents a highly promising modality within the domain of cancer treatment. CAR-T cell therapy has demonstrated notable efficacy in the treatment of hematological malignancies, solid tumors, and various infectious diseases. However, current CAR-T cell therapy is autologous, which presents challenges related to high costs, time-consuming manufacturing processes, and the necessity for careful patient selection. A potential resolution to this restriction could be found by synergizing CAR-T technology with the induced pluripotent stem cell (iPSC) technology. iPSC technology has the inherent capability to furnish an inexhaustible reservoir of T cell resources. Experimental evidence has demonstrated the successful generation of various human CAR-T cells using iPSC technology, showcasing high yield, purity, robustness, and promising tumor-killing efficacy. Importantly, this technology enables the production of clinical-grade CAR-T cells, significantly reducing manufacturing costs and time, and facilitating their use as allogeneic cell therapies to treat multiple cancer patients simultaneously. In this review, we aim to elucidate essential facets of current cancer therapy, delineate its utility, enumerate its advantages and drawbacks, and offer an in-depth evaluation of a novel and pragmatic approach to cancer treatment.

Current status and innovative developments of CAR-T-cell therapy for the treatment of breast cancer

Breast cancer will overtake all other cancers in terms of diagnoses in 2024. Breast cancer counts highest among women in terms of cancer incidence and death rates. Innovative treatment approaches are desperately needed because treatment resistance brought on by current clinical drugs impedes therapeutic efficacy. The T cell-based immunotherapy known as chimeric antigen receptor (CAR) T cell treatment, which uses the patient's immune cells to fight cancer, has demonstrated remarkable efficacy in treating hematologic malignancies; nevertheless, the treatment effects in solid tumors, like breast cancer, have not lived up to expectations. We discuss in detail the role of tumor-associated antigens in breast cancer, current clinical trials, barriers to the intended therapeutic effects of CAR-T cell therapy, and potential ways to increase treatment efficacy. Finally, our review aims to stimulate readers' curiosity by summarizing the most recent advancements in CAR-T cell therapy for breast cancer.

Exploring CAR-macrophages in non-tumor diseases: Therapeutic potential beyond cancer

BACKGROUND

After significant advancements in tumor treatment, personalized cell therapy based on chimeric antigen receptors (CAR) holds promise for transforming the management of various diseases. CAR-T therapy, the first approved CAR cell therapy product, has demonstrated therapeutic potential in treating infectious diseases, autoimmune disorders, and fibrosis. CAR-macrophages (CAR-Ms) are emerging as a promising approach in CAR immune cell therapy, particularly for solid tumor treatment, highlighting the feasibility of using macrophages to eliminate pathogens and abnormal cells.

AIM OF REVIEW

This review summarizes the progress of CAR-M therapy in non-tumor diseases and discusses various CAR intracellular activation domain designs and their potential to optimize therapeutic effects by modulating interactions between cellular components in the tissue microenvironment and CAR-M. Additionally, we discuss the characteristics and advantages of CAR-M therapy compared to traditional medicine and CAR-T/NK therapy, as well as the challenges and prospects for the clinical translation of CAR-M.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review provides a comprehensive understanding of CAR-M for the treatment of non-tumor diseases, analyzes the advantages and characteristics of CAR-M therapy, and highlights the important impact of CAR intracellular domain design on therapeutic efficacy. In addition, the challenges and clinical translation prospects of developing CAR-M as a new cell therapy are discussed.

Allogeneic chimeric antigen receptor cell therapies for cancer: progress made and remaining roadblocks

Chimeric antigen receptor (CAR) T cells are revolutionizing cancer therapy, particularly for haematological malignancies, conferring durable and sometimes curative responses in patients with advanced-stage disease. The CAR T cell products currently approved for clinical use are all autologous and are often effective; however, in patients who are lymphopenic and/or heavily pretreated with chemotherapy, autologous T cells can be difficult to harvest in sufficient numbers or have functional impairments that might ultimately render them less efficacious. Moreover, autologous products take several weeks to produce, and each product can be used in only one patient. By contrast, allogeneic CAR T cells can be produced for many patients using T cells from a single healthy donor, can be optimized for safety and efficacy, can be instantly available for 'off-the-shelf' use and, therefore, might also be more cost-effective. Despite these potential advantages, the development of allogeneic CAR T cells has lagged behind that of autologous products, owing to the additional challenges such as avoiding graft-versus-host disease and host-mediated graft rejection. Over the past few years, the development of advanced genome-editing techniques has facilitated the generation of novel allogeneic CAR T cell products. Furthermore, CAR cell products derived from other cell types such as induced pluripotent stem cells and natural killer cells are being investigated for clinical use. In this Review, we discuss the potential of allogeneic CAR cell products to expand life-saving immunotherapy to a much broader population of patients in the coming years, the progress made to date and strategies to overcome remaining hurdles.

Leveraging CAR macrophages targeting c-Met for precision immunotherapy in pancreatic cancer: insights from single-cell multi-omics

BACKGROUND

Pancreatic cancer is known for its poor prognosis and resistance to conventional therapies, largely due to the presence of cancer stem cells (CSCs) and aggressive angiogenesis. Effectively targeting these CSCs and associated angiogenic pathways is crucial for effective treatment. This study leverages single-cell multi-omics to explore a novel therapeutic approach involving Chimeric Antigen Receptor (CAR) macrophages engineered to target the c-Met protein on pancreatic CSCs.

METHODS

We employed single-cell RNA sequencing to analyze pancreatic cancer tissue, identifying c-Met as a key marker of CSCs. CAR macrophages were engineered using a lentiviral system to express a c-Met-specific receptor. The phagocytic efficiency of these CAR macrophages against pancreatic CSCs was assessed in vitro, along with their ability to inhibit angiogenesis. The in vivo efficacy of CAR macrophages was evaluated in a mouse model of pancreatic cancer.

RESULTS

CAR macrophages demonstrated high specificity for c-Met + CSCs, significantly enhancing phagocytosis and reducing the secretion of angiogenic factors such as VEGFA, FGF2, and ANGPT. In vivo, these macrophages significantly suppressed tumor growth and angiogenesis, prolonging survival in pancreatic cancer-bearing mice.

CONCLUSION

CAR macrophages targeting c-Met represent a promising therapeutic strategy for pancreatic cancer, offering targeted elimination of CSCs and disruption of tumor angiogenesis. This study highlights the potential of single-cell multi-omics in guiding the development of precision immunotherapies.

The Pluripotent Path to Immunotherapy

Adoptive cell therapy (ACT) enhances the patient's own immune cells' ability to identify and eliminate cancer cells. Several immune cell types are currently being applied in autologous ACT, including T cells, natural killer (NK) cells, and macrophages. The cells' inherent antitumor capacity can be used, or they can be targeted toward tumor-associated antigen through expression of a chimeric antigen receptor (CAR). Although CAR-based ACT has achieved great results in hematologic malignancies, the accessibility of ACT is limited by the autologous nature of the therapy. Induced pluripotent stem cells (iPSCs) hold the potential to address this challenge, because they can provide an unlimited source for the in vitro generation of immune cells. Various immune subsets have been generated from iPSC for application in ACT, including several T-cell subsets (αβT cells, mucosal-associated invariant T cells, invariant NKT [iNKT] cells, and γδT cells), as well as NK cells, macrophages, and neutrophils. iPSC-derived αβT, NK, and iNKT cells are currently being tested in phase I clinical trials. The ability to perform (multiplexed) gene editing at the iPSC level and subsequent differentiation into effector populations not only expands the arsenal of ACT but allows for development of ACT utilizing cell types which cannot be efficiently obtained from peripheral blood or engineered and expanded in vitro.

Silencing of SIRPα enhances the antitumor efficacy of CAR-M in solid tumors

The potential of macrophage-mediated phagocytosis as a cancer treatment is promising. Blocking the CD47-SIRPα interaction with a CD47-specific antibody significantly enhances macrophage phagocytosis. However, concerns regarding their toxicity to nontumor cells remain substantial. Here, we engineered chimeric antigen receptor macrophages (CAR-Ms) by fusing a humanized single-chain variable fragment with FcγRIIa and integrating short hairpin RNA to silence SIRPα, thereby disrupting the CD47-SIRPα signaling pathway. These modified CAR-shSIRPα-M cells exhibited an M1-like phenotype, superior phagocytic function, substantial cytotoxic effects on HER2-positive tumor cells, and the ability to eliminate patient-derived organoids. In vivo, CAR-M cells significantly inhibited tumor growth and prolonged survival in tumor-bearing mice. Notably, CAR-shSIRPα-M cells enhanced cytotoxic T-cell infiltration into tumors, thereby enhancing the antitumor response in both the humanized immune system mouse model and immunocompetent mice. Mechanistically, SIRPα inhibition activated inflammatory pathways and the cGAS-STING signaling cascade in CAR-M cells, leading to increased production of proinflammatory cytokines, reactive oxygen species, and nitric oxide, thereby enhancing their antitumor effects. These findings underscore the potential of SIRPα inhibition as a novel strategy to increase the antitumor efficacy of CAR-M cells in cancer immunotherapy, particularly against solid tumors.

CAR Macrophages: a promising novel immunotherapy for solid tumors and beyond

With the advent of adoptive cellular therapy, chimeric antigen receptor (CAR)-T cell therapy has gained widespread application in cancer treatment and has demonstrated significant efficacy against certain hematologic malignancies. However, due to the limitations of CAR-T cell therapy in treating solid tumors, other immune cells are being modified with CAR to address this issue. Macrophages have emerged as a promising option, owing to their extensive immune functions, which include antigen presentation, powerful tumor phagocytosis, and particularly active trafficking to the tumor microenvironment. Leveraging their unique advantages, CAR-macrophages (CAR-M) are expected to enhance the effectiveness of solid tumor treatments as a novel form of immunotherapy, potentially overcoming major challenges associated with CAR-T/NK therapy. This review outlines the primary mechanism underlying CAR-M and recent progressions in CAR-M therapy, while also discussing their further applications.

The next frontier in immunotherapy: potential and challenges of CAR-macrophages

Chimeric antigen receptor macrophage (CAR-MΦ) represents a significant advancement in immunotherapy, especially for treating solid tumors where traditional CAR-T therapies face limitations. CAR-MΦ offers a promising approach to target and eradicate tumor cells by utilizing macrophages' phagocytic and antigen-presenting abilities. However, challenges such as the complex tumor microenvironment (TME), variability in antigen expression, and immune suppression limit their efficacy. This review addresses these issues, exploring mechanisms of CAR-MΦ action, optimal construct designs, and interactions within the TME. It also delves into the ex vivo manufacturing challenges of CAR-MΦ, discussing autologous and allogeneic sources and the importance of stringent quality control. The potential synergies of integrating CAR-MΦ with existing cancer therapies like checkpoint inhibitors and conventional chemotherapeutics are examined to highlight possible enhanced treatment outcomes. Furthermore, regulatory pathways for CAR-MΦ therapies are scrutinized alongside established protocols for CAR-T cells, identifying unique considerations essential for clinical trials and market approval. Proposed safety monitoring frameworks aim to manage potential adverse events, such as cytokine release syndrome, crucial for patient safety. Consolidating current research and clinical insights, this review seeks to refine CAR-MΦ therapeutic applications, overcome barriers, and suggest future research directions to transition CAR-MΦ therapies from experimental platforms to standard cancer care options.

Emerging Innate Immune Cells in Cancer Immunotherapy: Promises and Challenges

Immune checkpoint inhibitor (ICI)-based therapy has made an unprecedented impact on survival benefit for a subset of cancer patients; however, only a subset of cancer patients is benefiting from ICI therapy if all cancer types are considered. With the advanced understanding of interactions of immune effector cell types and tumors, cell-based therapies are emerging as alternatives to patients who could not benefit from ICI therapy. Pioneering work of chimeric antigen receptor T (CAR-T) therapy for hematological malignancies has brought encouragement to a broad range of development for cellular-based cancer immunotherapy, both innate immune cell-based therapies and T-cell-based therapies. Innate immune cells are important cell types due to their rapid response, versatile function, superior safety profiles being demonstrated in early clinical development, and being able to utilize multiple allogeneic cell sources. Efforts on engineering innate immune cells and exploring their therapeutic potential are rapidly emerging. Some of the therapies, such as CD19 CAR natural killer (CAR-NK) cell-based therapy, have demonstrated comparable early efficacy with CD19 CAR-T cells. These studies underscore the significance of developing innate immune cells for cancer therapy. In this review, we focus on the current development of emerging NK cells, γδ T cells, and macrophages. We also present our views on potential challenges and perspectives to overcome these challenges.

Designing Chimeric Antigen Receptors for Myeloid Immune Cells

Chimeric antigen receptor (CAR) myeloid cells are a promising potential alternative to CAR T-cells for solid tumor therapies. Myeloid CAR therapies have been tested in preclinical studies by either transferring established CD3-based T-cell CARs into myeloid cells, or by designing myeloid-specific signaling domains. While ITAM-based myeloid receptors (e.g., Fc-receptors) were often outperformed by classic CD3ζ-designs, toll-interleukin-1 receptor (TIR) and Mer receptor tyrosine kinase (MerTK) have shown promise for improving myeloid-specific cell activation. Addition of CD147 to stimulate matrix-metalloproteinase production and of cytokine genes (e.g. interferon γ) may further improve the efficacy of CAR-myeloid cells in the tumor immune microenvironment. While most work focused on CAR monocytes and macrophages, CAR-DC cells are also being studied as tumor vaccines in preclinical and early clinical phases. Lastly, even though CAR neutrophils are disadvantaged by a short lifespan, they could become viable by transfusing them as undifferentiated myeloid progenitors instead of effector cells. Here, we summarize the status of preclinical and clinical research on different CAR myeloid strategies, compare receptor designs, outline gaps in knowledge, conflicting results, and approaches for future preclinical studies that will allow translation of these technologies to the clinic.

Nanomaterials in modulating tumor-associated macrophages and enhancing immunotherapy

Tumor-associated macrophages (TAMs) are predominantly present in the tumor microenvironment (TME) and play a crucial role in shaping the efficacy of tumor immunotherapy. These TAMs primarily exhibit a tumor-promoting M2-like phenotype, which is associated with the suppression of immune responses and facilitation of tumor progression. Interestingly, recent research has highlighted the potential of repolarizing TAMs from an M2 to a pro-inflammatory M1 status-a shift that has shown promise in impeding tumor growth and enhancing immune responsiveness. This concept is particularly intriguing as it offers a new dimension to cancer therapy by targeting the tumor microenvironment, which is a significant departure from traditional approaches that focus solely on tumor cells. However, the clinical application of TAM-modulating agents is often challenged by issues such as insufficient tumor accumulation and off-target effects, limiting their effectiveness and safety. In this regard, nanomaterials have emerged as a novel solution. They serve a dual role: as delivery vehicles that can enhance the accumulation of therapeutic agents in the tumor site and as TAM-modulators. This dual functionality of nanomaterials is a significant advancement as it addresses the key limitations of current TAM-modulating strategies and opens up new avenues for more efficient and targeted therapies. This review provides a comprehensive overview of the latest mechanisms and strategies involving nanomaterials in modulating macrophage polarization within the TME. It delves into the intricate interactions between nanomaterials and macrophages, elucidating how these interactions can be exploited to drive macrophage polarization towards a phenotype that is more conducive to anti-tumor immunity. Additionally, the review explores the burgeoning field of TAM-associated nanomedicines in combination with tumor immunotherapy. This combination approach is particularly promising as it leverages the strengths of both nanomedicine and immunotherapy, potentially leading to synergistic effects in combating cancer.

Sensor macrophages derived from human induced pluripotent stem cells to assess pyrogenic contaminations in parenteral drugs

Ensuring the safety of parenteral drugs before injection into patients is of utmost importance. New regulations around the globe and the need to refrain from using animals however, have highlighted the need for new cell sources to be used in next-generation bioassays to detect the entire spectrum of possible contaminating pyrogens. Given the current drawbacks of the Monocyte-Activation-Test (MAT) with respect to the use of primary peripheral blood mono-nuclear cells or the use of monocytic cell lines, we here demonstrate the manufacturing of sensor monocytes/macrophages from human induced pluripotent stem cells (iMonoMac), which are fully defined and superior to current cell products. Using a modern and scalable manufacturing platform, iMonoMac showed typical macrophage-like morphology and stained positive for several Toll like receptor (TLRs) such as TLR-2, TLR-5, TLR-4. Furthermore, iMonoMac derived from the same donor were sensitive to endotoxins, non-endotoxins, and process related pyrogens at a high dynamic range and across different cellular densities. Of note, iMonoMac showed increased sensitivity and reactivity to a broad range of pyrogens, demonstrated by the detection of interleukin-6 at low concentrations of LPS and MALP-2 which could not be reached using the current MAT cell sources. To further advance the system, iMonoMac or genetically engineered iMonoMac with NF-κB-luciferase reporter cassette could reveal a specific activation response while correlating to the classical detection method employing enzyme-linked immunosorbent assay to measure cytokine secretion. Thus, we present a valuable cellular tool to assess parenteral drugs safety, facilitating the future acceptance and design of regulatory-approved bioassays.

CAR-based immunotherapy for breast cancer: peculiarities, ongoing investigations, and future strategies

Surgery, chemotherapy, and endocrine therapy have improved the overall survival and postoperative recurrence rates of Luminal A, Luminal B, and HER2-positive breast cancers but treatment modalities for triple-negative breast cancer (TNBC) with poor prognosis remain limited. The effective application of the rapidly developing chimeric antigen receptor (CAR)-T cell therapy in hematological tumors provides new ideas for the treatment of breast cancer. Choosing suitable and specific targets is crucial for applying CAR-T therapy for breast cancer treatment. In this paper, we summarize CAR-T therapy's effective targets and potential targets in different subtypes based on the existing research progress, especially for TNBC. CAR-based immunotherapy has resulted in advancements in the treatment of breast cancer. CAR-macrophages, CAR-NK cells, and CAR-mesenchymal stem cells (MSCs) may be more effective and safer for treating solid tumors, such as breast cancer. However, the tumor microenvironment (TME) of breast tumors and the side effects of CAR-T therapy pose challenges to CAR-based immunotherapy. CAR-T cells and CAR-NK cells-derived exosomes are advantageous in tumor therapy. Exosomes carrying CAR for breast cancer immunotherapy are of immense research value and may provide a treatment modality with good treatment effects. In this review, we provide an overview of the development and challenges of CAR-based immunotherapy in treating different subtypes of breast cancer and discuss the progress of CAR-expressing exosomes for breast cancer treatment. We elaborate on the development of CAR-T cells in TNBC therapy and the prospects of using CAR-macrophages, CAR-NK cells, and CAR-MSCs for treating breast cancer.

CAR products from novel sources: a new avenue for the breakthrough in cancer immunotherapy

Chimeric antigen receptor (CAR) T cell therapy has transformed cancer immunotherapy. However, significant challenges limit its application beyond B cell-driven malignancies, including limited clinical efficacy, high toxicity, and complex autologous cell product manufacturing. Despite efforts to improve CAR T cell therapy outcomes, there is a growing interest in utilizing alternative immune cells to develop CAR cells. These immune cells offer several advantages, such as major histocompatibility complex (MHC)-independent function, tumor microenvironment (TME) modulation, and increased tissue infiltration capabilities. Currently, CAR products from various T cell subtypes, innate immune cells, hematopoietic progenitor cells, and even exosomes are being explored. These CAR products often show enhanced antitumor efficacy, diminished toxicity, and superior tumor penetration. With these benefits in mind, numerous clinical trials are underway to access the potential of these innovative CAR cells. This review aims to thoroughly examine the advantages, challenges, and existing insights on these new CAR products in cancer treatment.