CAR T Cell Therapy for Solid Tumors: Bright Future or Dark Reality?

Combinational CAR T-cell therapy for solid tumors: Requisites, rationales, and trials

Chimeric antigen receptor (CAR) T-cell therapy has achieved potent antitumor efficacy in hematological malignancies; however, because of limitations in CAR T-cell recruitment, infiltration, activation, and functional persistence in the tumor, its efficacy in solid tumors has been suboptimal. To overcome these challenges, combinational strategies that include chemotherapy, radiation therapy, or immune checkpoint inhibitor agent therapy with CAR T-cell therapy are being investigated. The established functional characteristics of the abovementioned therapies provide a rationale for the use of a combinational approach with CAR T cells. Chemotherapy reshapes the peritumoral stroma, decreases the immunosuppressive cell population, and promotes a proinflammatory milieu, all of which allow for increased recruitment, infiltration, and accumulation of CAR T cells. Radiation therapy promotes a chemokine gradient, which augments tumor infiltration by CAR T cells and further increases expression of tumor-associated antigens, allowing for increased activation of CAR T cells. Immune checkpoint inhibitor agent therapy inactivates T-cell exhaustion pathways-most notably, the PD1/PDL1 pathway-thereby improving the functional persistence of CAR T cells and promoting endogenous immunity. In this review, we discuss the requisites and rationales for combinational therapy, and we review 25 ongoing phase I and II clinical trials, of which 4 use chemotherapy, 3 use radiation therapy, 11 use immunotherapy, and 7 use another agent. While safety, efficacy, and improved outcomes are the primary goals of these ongoing studies, the knowledge gained from them will help pave the way for subsequent studies focused on optimizing combinational regimens and identifying predictive biomarkers.

Triple knockdown of CD11a, CD49d, and PSGL1 in T cells reduces CAR-T cell toxicity but preserves activity against solid tumors in mice

Chimeric antigen receptor (CAR)-T cell therapies have revolutionized the landscape of cancer treatment, in particular in the context of hematologic malignancies. However, for solid tumors that lack tumor-specific antigens, CAR-T cells can infiltrate and attack nonmalignant tissues expressing the CAR target antigen, leading to on-target, off-tumor toxicity. Severe on-target, off-tumor toxicities have been observed in clinical trials of CAR-T therapy for solid tumors, highlighting the need to address this issue. Here, we demonstrated that targeting the cell adhesion and migration molecules lymphocyte function-associated antigen 1 (LFA-1; CD11a/CD18) and very late activation antigen 4 (VLA-4; CD49d/CD29) with blocking antibodies reduced the on-target, off-tumor toxicity of CAR-T cells in mice. To translate this observation into improved CAR-T cell therapy, we either knocked out both CD11a and CD49d or knocked down CD11a and CD49d along with PSGL1, another cell adhesion molecule, in CAR-T cells. We found that these modified CAR-T cells exhibited reduced on-target, off-tumor toxicity in vivo without affecting CAR-T cell efficacy. Furthermore, we showed that this approach promoted T cell memory formation and decreased tonic signaling. On the basis of these data, we engineered a human version of these low-toxicity CAR-T cells and further validated the feasibility of this approach in vitro and in vivo. Together, these results provide a potential solution to address the clinical challenge of on-target, off-tumor toxicity in CAR-T therapy.

Application of adoptive cell therapy in malignant melanoma

Cutaneous melanoma is one of the most aggressive skin cancers originating from skin pigment cells. Patients with advanced melanoma suffer a poor prognosis and generally cannot benefit well from surgical resection and chemo/target therapy due to metastasis and drug resistance. Thus, adoptive cell therapy (ACT), employing immune cells with specific tumor-recognizing receptors, has emerged as a promising therapeutic approach to display on-tumor toxicity. This review discusses the application, efficacy, limitations, as well as future prospects of four commonly utilized approaches -including tumor-infiltrating lymphocytes, chimeric antigen receptor (CAR) T cell, engineered T-cell receptor T cells, and chimeric antigen receptor NK cells- in the context of malignant melanoma.

Cardiovascular Complications of Immune Effector Cell Therapies in Pediatric Hematological and Solid Tumors

BACKGROUND

Immune effector cell (IEC) therapies, including chimeric antigen receptor (CAR)-modified T-cell therapy, have shown efficacy in pediatric B-cell acute lymphoblastic leukemia (B-ALL) and are being investigated for other malignancies. A common toxicity associated with IEC therapy is cytokine release syndrome (CRS), which can lead to cardiovascular decompensation due to systemic inflammation. Data are limited regarding cardiovascular adverse effects in children. This study aims to describe the cardiovascular adverse effect profile of IEC therapies in pediatric patients with hematologic and solid tumor malignancies.

METHODS

We retrospectively reviewed patients who received IECs directed towards various targets in patients with hematologic, solid, and brain tumor malignancies from January 2014 to June 2023 at Texas Children's Hospital. The primary end point was hypotension requiring vasoactive support and/or heart failure within 30 days of infusion.

RESULTS

A total of 203 patients met inclusion criteria. Pretreatment echocardiogram was available for 142 (70%) pediatric patients, of whom 140 (96%) had normal baseline systolic function. Hypotension requiring vasoactive support occurred in 26 (13%) patients. Hematologic malignancy indications (p = 0.002), total body irradiation (TBI) (p = 0.002), and allogenic hematopoietic stem cell transplants (HCT) (p = 0.035) were associated with increased risk of hypotension requiring vasoactive support. Follow-up echocardiograms were available for 14 patients who met the primary end point, and all showed return to baseline within 6 months.

CONCLUSIONS

Significant hemodynamic compromise occurred in a minority of patients treated with IEC therapies. All experiencing cardiac dysfunction had recovery of function, and there was no cardiovascular-related mortality.

Digestive cancers: mechanisms, therapeutics and management

Cancers of the digestive system are major contributors to global cancer-associated morbidity and mortality, accounting for 35% of annual cases of cancer deaths. The etiologies, molecular features, and therapeutic management of these cancer entities are highly heterogeneous and complex. Over the last decade, genomic and functional studies have provided unprecedented insights into the biology of digestive cancers, identifying genetic drivers of tumor progression and key interaction points of tumor cells with the immune system. This knowledge is continuously translated into novel treatment concepts and targets, which are dynamically reshaping the therapeutic landscape of these tumors. In this review, we provide a concise overview of the etiology and molecular pathology of the six most common cancers of the digestive system, including esophageal, gastric, biliary tract, pancreatic, hepatocellular, and colorectal cancers. We comprehensively describe the current stage-dependent pharmacological management of these malignancies, including chemo-, targeted, and immunotherapy. For each cancer entity, we provide an overview of recent therapeutic advancements and research progress. Finally, we describe how novel insights into tumor heterogeneity and immune evasion deepen our understanding of therapy resistance and provide an outlook on innovative therapeutic strategies that will shape the future management of digestive cancers, including CAR-T cell therapy, novel antibody-drug conjugates and targeted therapies.

The guided fire from within: intratumoral administration of mRNA-based vaccines to mobilize memory immunity and direct immune responses against pathogen to target solid tumors

We investigated a novel cancer immunotherapy strategy that effectively suppresses tumor growth in multiple solid tumor models and significantly extends the lifespan of tumor-bearing mice by introducing pathogen antigens into tumors via mRNA-lipid nanoparticles. The pre-existing immunity against the pathogen antigen can significantly enhance the efficacy of this approach. In mice previously immunized with BNT162b2, an mRNA-based COVID-19 vaccine encoding the spike protein of the SARS-CoV-2 virus, intratumoral injections of the same vaccine efficiently tagged the tumor cells with mRNA-expressed spike protein. This action rapidly mobilized the pre-existing memory immunity against SARS-CoV-2 to kill the cancer cells displaying the spike protein, while concurrently reprogramming the tumor microenvironment (TME) by attracting immune cells. The partial elimination of tumor cells in a normalized TME further triggered extensive tumor antigen-specific T cell responses through antigen spreading, eventually resulting in potent and systemic tumor-targeting immune responses. Moreover, combining BNT162b2 treatment with anti-PD-L1 therapy yielded a more substantial therapeutic impact, even in "cold tumor" types that are typically less responsive to treatment. Given that the majority of the global population has acquired memory immunity against various pathogens through infection or vaccination, we believe that, in addition to utilizing the widely held immune memory against SARS-CoV-2 via COVID-19 vaccine, mRNA vaccines against other pathogens, such as Hepatitis B Virus (HBV), Common Human Coronaviruses (HCoVs), and the influenza virus, could be rapidly transitioned into clinical use and holds great promise in treating different types of cancer. The extensive selection of pathogen antigens expands therapeutic opportunities and may also overcome potential drug resistance.

APOBEC3B expression in 293T viral producer cells drives mutations in chimeric antigen receptors and reduces CAR T cell efficacy

Chimeric antigen receptor (CAR) T cells are a clinically approved therapy for blood cancers. To produce clinical-grade CAR T cells, a retroviral or lentiviral vector is used to deliver the CAR and associated genes to patient T cells. Apolipoprotein B editing enzyme, catalytic polypeptide 3 (APOBEC3) enzymes are known to be upregulated after transfection and retroviral infection and to deaminate cytidine to uracil in nucleic acids, resulting in cytidine-to-thymine mutations in DNA. Here, we hypothesized that APOBEC3 enzymes, induced during the production of CAR T cells, impact the efficacy of the resulting CAR T cells. We demonstrated that APOBEC3 family member APOBEC3B was upregulated at the RNA and protein levels after transfection of HEK293T cells with plasmids to make lentivirus, and that APOBEC3 signature mutations were present in the CAR construct. APOBEC3B overexpression in HEK293T cells led to further mutations in the resulting CAR T cells, and significantly decreased CAR T cell killing. APOBEC3B knockout in HEK293T cells led to reduced mutations in the CAR construct and significantly increased in CAR T cell killing. These results suggest that generation of CAR-expressing viruses from producer cell lines deficient in genome-modifying proteins such as APOBEC3B could enhance the quality of CAR T cell production.

Optimizing Adoptive Cell Therapy for Solid Tumors via Epigenetic Regulation of T-cell Destiny

Adoptive cell therapy (ACT) emerged as a promising approach for cancer treatment, yet its application in solid tumors faced challenges such as inadequate tumor infiltration and cellular dysfunction. Histone acetylation is reported to play a crucial role in restoring T-cell function within tumor tissues. Building upon previous research, a novel strategy involving the co-loading of two drugs, G3C12 and vorinostat (SAHA), into PLGA microspheres to form G3C12+SAHA@PLGA is developed for intratumoral injection. The G3C12 peptide enhances adoptive T-cell recruitment to the tumor site by modulating the binding state of IFN-γ. While SAHA, a histone deacetylase inhibitor, promotes memory phenotypes of infiltrating T-cells and prevents their transition to an exhausted state. This synergistic approach effectively augmentes the efficacy of ACT in the "cold" tumor model (4T1) or the "hot" tumor model (CT26). These findings highlight the potential of combining epigenetic regulation with recruitment signaling as a means to enhance the therapeutic impact of ACT in treating solid tumors.

Advances in cell therapy: progress and challenges in hematological and solid tumors

Cell-based therapies harness the endogenous ability of the immune system to fight cancer and have shown promising results in the treatment of hematological malignancies. However, their clinical application beyond B cell malignancies is hampered by numerous hurdles, ranging from relapsed disease to a hostile tumor microenvironment (TME). Recent advances in cell engineering and TME modulation may expand the applicability of these therapies to a wider range of cancers, creating new treatment possibilities. Breakthroughs in advanced gene editing and sophisticated cell engineering, have also provided promising solutions to longstanding challenges. In this review, we examine the challenges and future directions of the most prominent cell-based therapies, including chimeric antigen receptor (CAR)-T cells, tumor-infiltrating lymphocytes (TILs), and natural killer (NK) cells, and emerging modalities. We provide a comprehensive analysis of emerging cell types and combination strategies translated into clinical trials, offering insights into the next generation of cell-based cancer treatments.

CAR T-cells for pediatric solid tumors: where to go from here?

Despite the great success that chimeric antigen receptor (CAR) T-cells have had in patients with B-cell malignancies and multiple myeloma, they continue to have limited efficacy against most solid tumors. Especially in the pediatric population, pre- and post-treatment biopsies are rarely performed due to ethical reasons, and thus, our understanding is still very limited regarding the mechanisms in the tumor microenvironment by which tumor cells exclude effectors and attract immune-suppressive cells. Nevertheless, based on the principles that are known, current T-cell engineering has leveraged some of these processes and created more potent CAR T-cells. The recent discovery of new oncofetal antigens and progress made in CAR design have expanded the potential pool of candidate antigens for therapeutic development. The most promising approaches to enhance CAR T-cells are novel CAR gating strategies, creative ways of cytokine delivery to the TME without enhancing systemic toxicity, and hijacking the chemokine axis of tumors for migratory purposes. With these new modifications, the next step in the era of CAR T-cell development will be the clinical validation of these promising preclinical findings.

IL-18R supported CAR T cells targeting oncofetal tenascin C for the immunotherapy of pediatric sarcoma and brain tumors

BACKGROUND

Oncofetal splice variants of extracellular matrix (ECM) proteins present a unique group of target antigens for the immunotherapy of pediatric cancers. However, limited data is available if these splice variants can be targeted with T cells expressing chimeric antigen receptors (CARs).

METHODS

To determine the expression of the oncofetal version of tenascin C (TNC) encoding the C domain (C.TNC) in pediatric brain and solid tumors, we used quantitative reverse transcription PCR and immunohistochemistry. Genetically modified T cells were generated from human peripheral blood mononuclear cells and evaluated in vitro and in vivo.

RESULTS

We demonstrate that C.TNC is expressed on a protein level in pediatric tumors, including diffuse intrinsic pontine glioma, osteosarcoma, rhabdomyosarcoma, and Ewing sarcoma. We generate C.TNC-CAR T cells and establish that these recognize and kill C.TNC-positive tumor cells. However, their antitumor activity in vivo is limited. To improve the effector function of C.TNC-CAR T cells, we design a leucine zipper-based chimeric cytokine receptor that activates interleukin-18 signaling pathways (Zip18R). Expression of Zip18R in C.TNC-CAR T cells improves their ability to secrete cytokines and expand in repeat stimulation assays. C.TNC-CAR.Zip18R T cells also have significantly greater antitumor activity in vivo compared with unmodified C.TNC-CAR T cells.

CONCLUSIONS

Our study identifies the C domain of the ECM protein TNC as a promising CAR T-cell therapy for pediatric solid tumors and brain tumors. While we focus here on pediatric cancer, our work has relevance to a broad range of adult cancers that express C.TNC.

Prospects of anti-GD2 immunotherapy for retinoblastoma

Retinoblastoma is the most common type of eye tumor in infants and children. Current treatments for retinoblastoma include intravenous chemotherapy, intra-arterial chemotherapy, intravitreal chemotherapy, cryotherapy, radiotherapy, and surgery. However, these treatments come accompanied by adverse effects such as the toxic side effects of chemotherapeutic drugs, post-operative complications including blindness after surgery, or other complications caused by radiotherapy. Immunotherapy is more promising for its low toxicity on normal cells and effectively improves the quality of life of patients. Disialoganglioside (GD2), a sphingolipid expressed on the surface of retinoblastoma, is a potential therapeutic target for retinoblastoma. We summarized immunotherapeutic approaches for both preclinical studies and clinical trials of GD2. An anti-GD2 monoclonal antibody (Dinutuximab), which has been approved for the treatment of high-risk neuroblastomas, has shown promising efficacy in improving patients' prognosis. Additionally, chimeric antigen receptors (CAR)-T therapy, GD2 vaccines and nanoparticles are also potential therapeutics. Finally, we discuss the prospects and current limitations of these immunotherapeutic approaches for treating retinoblastoma, as well as how to address these problems.

Innovative pan-tumor target strategy for CAR-T therapy: cancer-specific exons as novel targets for pediatric solid and brain tumors

Chimeric antigen receptor T-cell (CAR-T) immunotherapy has achieved remarkable success in treating chemotherapy-refractory hematological malignancies. However, its efficacy in solid and brain tumors remains limited due to challenges such as insufficient target antigens, poor T-cell adaptability, inefficient tumor site trafficking, and the immunosuppressive tumor microenvironment. To address these challenges, Shaw and colleagues proposed an innovative strategy targeting cancer-specific exons (CSEs) in pediatric solid and brain tumors. Using RNA sequencing data from 16 tumor types, the study identified 157 highly tumor-specific targets, including both known and novel proteins. The researchers validated several targets, including FN1 and COL11A1, demonstrating their therapeutic potential in in vitro and in vivo models. The study's approach of integrating exon-level analysis with a broad search for extracellular matrix proteins offers a new frontier for CAR-T therapy, providing valuable insights for improving immunotherapy in pediatric solid tumors. Although promising, the study also highlights the need for further evaluation of tumor recurrence and CAR-T cell exhaustion. The identification of novel pan-tumor targets may revolutionize CAR-T therapy design and expand its application in pediatric cancer treatment.

The mechanisms of B-cell acute lymphoblastic leukemia relapsing following chimeric antigen receptor-T cell therapy; the plausible future strategies

Research has demonstrated the high mortality and morbidity associated with B-Acute lymphoblastic lymphoma (B-ALL). Researchers have developed several therapeutic approaches to combat the disorder. Recently, researchers developed chimeric antigen receptors (CARs)-T cells, which recognize antigens independently of major histocompatibility complexes (MHCs) and activate at a higher level with additional persistence. However, relapsing B-ALL has been reported in several cases. This review article was aimed to collecting recent information regarding the mechanisms used by B-ALL-related lymphocytes to escape from CAR-T cells and the plausible resolution projects.

Inhibition of K+ Channels Affects the Target Cell Killing Potential of CAR T Cells

Ion channels of T cells (Kv1.3, KCa3.1, and CRAC) participate in the regulation of activation and effector functions via modulation of the Ca2+-dependent pathway. T cells expressing chimeric antigen receptors (CAR T cells) showed a remarkable role in anti-tumor therapy, especially in the treatment of chemotherapy-resistant liquid cancers. Nevertheless, many challenges remain to be overcome to improve the treatment for solid tumors. In this study, we assessed the expression and role of ion channels in CAR T cells. We found that HER2-specific CAR T cells had higher KCa3.1 conductance compared to the non-transduced (NT, control) cells, which was more prominent in the CD8+ population (CD4+ cell also showed elevation). Conversely, the Kv1.3 expression level was the same for all cell types (CD4+, CD8+, CAR, and NT). Single-cell Ca2+ imaging revealed that thapsigargin-induced SOCE via CRAC is suppressed in CD8+ CAR T cells, unlike for CD4+ and CD8+ NT cells. To dissect the functional role of Kv1.3 and KCa3.1, we used specific antagonists (Kv1.3: Vm24; KCa3.1: TRAM-34): the target cell elimination capacity of the CD8+ CAR T cells was improved either by blocking KCa3.1 or Kv1.3. These results imply that ion channels could be a target in CAR T cell immunotherapy elaboration.

Collagen extracellular matrix promotes gastric cancer immune evasion by activating IL4I1-AHR signaling

BACKGROUND

Gastric cancer (GC) remains a significant global health challenge with poor prognosis, partly due to its ability to evade the immune system. The extracellular matrix (ECM), particularly collagen, plays a crucial role in tumor immune evasion, but the underlying mechanisms are not fully understood. This study investigates the role of collagen ECM in promoting immune evasion in gastric cancer by activating the IL4I1-AHR signaling pathway.

METHODS

We cultured gastric cancer cells in 3D collagen gels and assessed their immune evasion capabilities by co-culturing with HER2-specific CAR-T cells. The expression of IL4I1 and its metabolites was analyzed, and the role of integrin αvβ1 in mediating the effects of collagen was explored. Additionally, the impact of IL4I1-induced AHR activation on CAR-T cell exhaustion was evaluated, both in vitro and in vivo.

RESULTS

We found that gastric cancer cells cultured on collagen exhibited increased resistance to CAR-T cell cytotoxicity, which was associated with upregulated immune checkpoint molecules and downregulated effector cytokines on CAR-T cells. This was linked to increased IL4I1 expression, which was further induced by integrin αvβ1 signaling within the 3D collagen environment. IL4I1 metabolites, particularly KynA, promoted CAR-T cell exhaustion by activating the AHR pathway, leading to decreased cytotoxicity and tumor growth inhibition.

CONCLUSIONS

Our study reveals a novel mechanism by which the collagen ECM facilitates immune evasion in gastric cancer through the activation of IL4I1-AHR signaling, contributing to CAR-T cell exhaustion. Targeting this pathway could potentially enhance the efficacy of CAR-T cell therapy in gastric cancer.

Intrinsic ADRB2 inhibition improves CAR-T cell therapy efficacy against prostate cancer

Chimeric antigen receptor (CAR)-T cell therapy has shown limited success in patients with solid tumors. Recent in vitro and in vivo data have shown that adrenoceptor beta-2 (ADRB2) is a novel checkpoint receptor that inhibits T cell-mediated anti-tumor responses. To inhibit ADRB2-mediated inhibitory signaling, we downregulated ADRB2 in CAR-T (shβ2-CAR-T) cells via RNA interference, assessed different parameters, and compared them with conventional second-generation CAR-T cells. ADRB2 knockdown CAR-T cells exhibited enhanced cytotoxicity against prostate cancer cell lines in vitro, by increasing CD69, CD107a, GzmB, IFN-γ, T-bet, and GLUT-1. In addition, ADRB2 deficiency led to improved proliferation, increased CD8/CD4 T cell ratio, and decreased apoptosis in CAR-T cells. shβ2-CAR-T cells expressed more Bcl-2 and led to the generation of more significant proportions of T central memory cells. Finally, the ZAP-70/NF-κB signaling axis was shown to be responsible for the improved functions of novel CAR-T cells. In tumor-bearing mice, shβ2-CAR-T cells performed better than conventional CAR-T cells in eradicating prostate tumors. The study provides the basis for future clinical and translational CAR-T cell research to focus on adrenergic stress-mediated challenges in the tumor microenvironment of stressed tumors.

Physicochemical Stability Study of the Morphine-Bupivacaine-Ziconotide Association

OBJECTIVE

The aim of this study was to investigate the physicochemical stability of morphine-bupivacaine-ziconotide mixtures used in intrathecal analgesia in polypropylene syringes and intrathecal pumps.

MATERIALS AND METHODS

The stability study method was conceived according to International Council for Harmonisation guidelines. For propylene syringes, six different mixtures of morphine-bupivacaine and ziconotide were assessed over seven days. Two storage temperatures were tested (5 °C ± 3 °C and 25 °C ± 2 °C). For implantable pumps, nine different mixtures were assessed over 60 days and stored at 37 °C. Assays were performed using ultrahigh-pressure liquid chromatography. Turbidity and pH also were measured throughout the study.

RESULTS

Results confirmed excellent physicochemical stability for morphine and bupivacaine in the study for all conditions investigated (pumps at 37 °C, polypropylene syringes at 5 °C ± 3 °C and 25 °C ± 2 °C). Concerning ziconotide, after seven days, our study showed that every 95% confidence interval calculated had lower bounds >90% for all mixtures stored in polypropylene syringes. In implantable pumps, a decrease of the concentration was observed in all the mixtures studied. Moreover, the appearance of a degradation product confirmed the ziconotide degradation.

CONCLUSION

All results are in favor with a physicochemical stable preparation for six mixture profiles when stored in polypropylene syringes at 5 °C ± 3 °C and 25 °C ± 2 °C. For mixtures stored in implantable pumps, the efficacy should decrease over time owing to the degradation of ziconotide. A trade-off between high morphine concentration and increased refill interval will need to be found by clinicians.

Using Spectral Flow Cytometry for CAR T-Cell Clinical Trials: Game Changing Technologies Enabling Novel Therapies

Monitoring chimeric antigen redirected (CAR) T-cells post-infusion in clinical trials is a specialized application of flow cytometry. Unlike the CAR T-cell monitoring for individual patients conducted in clinical laboratories, the data generated during a clinical trial will be used not only to monitor the therapeutic response of a single patient, but determine the success of the therapy itself, or even of an entire class of therapeutic compounds. The data, typically acquired at multiple testing laboratories, will be compiled into a single database. The data may also be used for mathematical modeling of cellular kinetics or to identify predictive biomarkers. With the expanded context of use, a robust, standardized assay is mandatory in order to generate a valuable and reliable data set. Hence, the requirements for assay validation, traceable calibration, technology transfer, cross-instrument standardization and regulatory compliance are high.

Engineered mesenchymal stem cell-derived extracellular vesicles: kill tumors and protect organs

Solid tumors cause 90% of cancers and remain the primary cause of mortality. However, treating solid tumors presents significant challenges due to the complex tumor microenvironment and drug resistance, leading to inadequate treatment targeting and severe side effects. Surgery, radiotherapy, and chemotherapy Although it is an effective method for the treatment of solid tumors, it can lead to organ dysfunction and affect patient prognosis. Therefore, it is imperative to improve treatment precision and organ repair capabilities to manage solid tumors. Mesenchymal stem cell extracellular vesicles (MSC-EVs) have wide application prospects as a new agent for solid tumor therapy. Firstly, MSC-EVs is a derivative of MSCs. It has the function of promoting tissue regeneration by inducing dedifferentiation in surviving cells after injury. Additionally, MSC-EVs offer unique advantages in terms of safety, stability and penetrability, making them a promising extracellular therapeutic modality for solid tumor treatment. Finally, MSC-EVs are able to enhance therapeutic efficacy through engineering strategies. To sum up, this review takes MSC-EVs as its object. And then we discuss recent advancements and engineering strategies in the use of MSC-EVs for soid tumor suppression. This review aims to inspire researchers to devise a new method for effectively treat solid tumors.

Investigating the Immune-Stimulating Potential of β-Glucan from Aureobasidium pullulans in Cancer Immunotherapy

β-glucan, a polysaccharide found in various sources, exhibits unique physicochemical properties, yet its high polymerization limits clinical applications because of its solubility. Addressing this limitation, we introduce PPTEE-glycan, a highly purified soluble β-1,3/1,6-glucan derived from Aureobasidium pullulans. The refined PPTEE-glycan demonstrated robust immune stimulation in vitro, activated dendritic cells, and enhanced co-stimulatory markers, cytokines, and cross-presentation. Formulated as a PPTEE + microemulsion (ME), it elevated immune responses in vivo, promoting antigen-specific antibodies and CD8+ T cell proliferation. Intratumoral administration of PPTEE + ME in tumor-bearing mice induced notable tumor regression, which was linked to the activation of immunosuppressive cells. This study highlights the potential of high-purity Aureobasidium pullulans-derived β-glucan, particularly PPTEE, as promising immune adjuvants, offering novel avenues for advancing cancer immunotherapy.

Ecological and evolutionary dynamics to design and improve ovarian cancer treatment

Ovarian cancer ecosystems are exceedingly complex, consisting of a high heterogeneity of cancer cells. Development of drugs such as poly ADP-ribose polymerase (PARP) inhibitors, targeted therapies and immunotherapies offer more options for sequential or combined treatments. Nevertheless, mortality in metastatic ovarian cancer patients remains high because cancer cells consistently develop resistance to single and combination therapies, urging a need for treatment designs that target the evolvability of cancer cells. The evolutionary dynamics that lead to resistance emerge from the complex tumour microenvironment, the heterogeneous populations, and the individual cancer cell's plasticity. We propose that successful management of ovarian cancer requires consideration of the ecological and evolutionary dynamics of the disease. Here, we review current options and challenges in ovarian cancer treatment and discuss principles of tumour evolution. We conclude by proposing evolutionarily designed strategies for ovarian cancer, with the goal of integrating such principles with longitudinal, quantitative data to improve the treatment design and management of drug resistance. KEY POINTS/HIGHLIGHTS: Tumours are ecosystems in which cancer and non-cancer cells interact and evolve in complex and dynamic ways. Conventional therapies for ovarian cancer inevitably lead to the development of resistance because they fail to consider tumours' heterogeneity and cellular plasticity. Eco-evolutionarily designed therapies should consider cancer cell plasticity and patient-specific characteristics to improve clinical outcome and prevent relapse.

CAR-T therapy for ovarian cancer: Recent advances and future directions

Ovarian cancer (OC) is a common gynecological tumor with high mortality, which is difficult to control its progression with conventional treatments and is prone to recurrence. Recent studies have identified OC as an immunogenic tumor that can be recognized by the host immune system. Immunotherapy for OC is being evaluated, but approaches such as immune checkpoint inhibitors have limited efficacy, adoptive cell therapy is an alternative therapy, in which CAR(chimeric antigen receptor)-T therapy has been applied to the clinical treatment of hematological malignancies. In addition, CAR-NK and CAR-macrophage (CAR-M) have also shown great potential in the treatment of solid tumors. Here, we discuss recent advances in preclinical and clinical studies of CAR-T for OC treatment, introduce the efforts made by researchers to modify the structure of CAR in order to achieve effective OC immunotherapy, as well as the research status of CAR-NK and CAR-M, and highlight emerging therapeutic opportunities that can be utilized to improve the survival of patients with OC using CAR-based adoptive cell therapy.

Engineering M1 macrophages with targeting aptamers for enhanced adoptive immunotherapy by modifying the cell surface

Macrophages play a critical role in the body's defense against cancer by phagocytosing tumor cells, presenting antigens, and activating adaptive T cells. However, macrophages are intrinsically incapable of delivering targeted cancer immunotherapies. Engineered adoptive cell therapy introduces new targeting and antitumor capabilities by modifying macrophages to enhance the innate immune response of cells and improve clinical efficacy. In this study, we developed engineered macrophage cholesterol-AS1411-M1 (CAM1) for cellular immunotherapy. To target macrophages, cholesterol-AS1411 aptamers were anchored to the surface of M1 macrophages to produce CAM1 without genetic modification or cell damage. CAM1 induced significantly higher apoptosis/mortality than unmodified M1 macrophages in murine breast cancer cells. Anchoring AS1411 on the surface of macrophages provided a novel approach to construct engineered macrophages for tumor immunotherapy.

Generation of Murine Chimeric Antigen Receptor-Modified T Cells for In Vivo Studies in Syngeneic Tumor Models

CAR-T cell therapy has emerged as a potent and effective tool in the immunotherapy of refractory cancers. However, challenges exist in their clinical application, necessitating extensive preclinical research to optimize their function. Various preclinical in vitro and in vivo models have been proposed for such purpose; among which immunocompetent mouse models serve as an invaluable tool in studying host immune interactions within a more realistic simulation of the tumor milieu. We hereby describe a standardized protocol for the generation of high-titer γ-retroviral vectors through transfection of the HEK293T packaging cell line. The virus-containing supernatant is further concentrated using an inhouse concentrator solution, titrated, and applied to mouse T cells purified via a convenient and rapid method by nylon-wool columns. Using the method presented here, we were able to achieve high titer γ-retrovirus and highly pure mouse T cells with desirable CAR transduction efficiency. The mouse CAR T cells produced through this protocol demonstrate favorable CAR expression and viability, thus making them suitable for further in vitro/in vivo assays. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Production of γ-retroviral vectors from retrovirus-backbone plasmids Basic Protocol 2: Concentration of γ-retrovirus-containing supernatants Basic Protocol 3: Titration of concentrated γ-retrovirus Basic Protocol 4: Isolation and activation of mouse T cells Basic Protocol 5: Transduction of activated mouse T cells, assessment of CAR expression, and expansion of CAR T cells for further in vitro/in vivo studies Support Protocol: Surface staining of cells for flow cytometric assessment of CAR expression.

CAR T-cells targeting FGFR4 and CD276 simultaneously show potent antitumor effect against childhood rhabdomyosarcoma

Chimeric antigen receptor (CAR) T-cells targeting Fibroblast Growth Factor Receptor 4 (FGFR4), a highly expressed surface tyrosine receptor in rhabdomyosarcoma (RMS), are already in the clinical phase of development, but tumour heterogeneity and suboptimal activation might hamper their potency. Here we report an optimization strategy of the co-stimulatory and targeting properties of a FGFR4 CAR. We replace the CD8 hinge and transmembrane domain and the 4-1BB co-stimulatory domain with those of CD28. The resulting CARs display enhanced anti-tumor activity in several RMS xenograft models except for an aggressive tumour cell line, RMS559. By searching for a direct target of the RMS core-regulatory transcription factor MYOD1, we identify another surface protein, CD276, as a potential target. Bicistronic CARs (BiCisCAR) targeting both FGFR4 and CD276, containing two distinct co-stimulatory domains, have superior prolonged persistent and invigorated anti-tumor activities compared to the optimized FGFR4-specific CAR and the other BiCisCAR with the same 4-1BB co-stimulatory domain. Our study thus lays down the proof-of-principle for a CAR T-cell therapy targeting both FGFR4 and CD276 in RMS.

Endogenous bystander killing mechanisms enhance the activity of novel FAP-specific CAR-T cells against glioblastoma

Objectives

CAR-T cells are being investigated as a novel immunotherapy for glioblastoma, but clinical success has been limited. We recently described fibroblast activation protein (FAP) as an ideal target antigen for glioblastoma immunotherapy, with expression on both tumor cells and tumor blood vessels. However, CAR-T cells targeting FAP have never been investigated as a therapy for glioblastoma.

Methods

We generated a novel FAP targeting CAR with CD3ζ and CD28 signalling domains and tested the resulting CAR-T cells for their lytic activity and cytokine secretion function in vitro (using real-time impedance, flow cytometry, imaging and bead-based cytokine assays), and in vivo (using a xenograft mimicking the natural heterogeneity of human glioblastoma).

Results

FAP-CAR-T cells exhibited target specificity against model cell lines and potent cytotoxicity against patient-derived glioma neural stem cells, even when only a subpopulation expressed FAP, indicating a bystander killing mechanism. Using co-culture assays, we confirmed FAP-CAR-T cells mediate bystander killing of antigen-negative tumor cells, but only after activation by FAP-positive target cells. This bystander killing was at least partially mediated by soluble factors and amplified by IL-2 which activated the non-transduced fraction of the CAR-T product. Finally, a low dose of intravenously administered FAP-CAR-T cells controlled, without overt toxicity, the growth of subcutaneous tumors created using a mixture of antigen-negative and antigen-positive glioblastoma cells.

Conclusions

Our findings advance FAP as a leading candidate for clinical CAR-T therapy of glioblastoma and highlight under-recognised antigen nonspecific mechanisms that may contribute meaningfully to the antitumor activity of CAR-T cells.

Activating innate immune responses repolarizes hPSC-derived CAR macrophages to improve anti-tumor activity

Generation of chimeric antigen receptor macrophages (CAR-Ms) from human pluripotent stem cells (hPSCs) offers new prospects for cancer immunotherapy but is currently challenged by low differentiation efficiency and limited function. Here, we develop a highly efficient monolayer-based system that can produce around 6,000 macrophages from a single hPSC within 3 weeks. Based on CAR structure screening, we generate hPSC-CAR-Ms with stable CAR expression and potent tumoricidal activity in vitro. To overcome the loss of tumoricidal activity of hPSC-CAR-Ms in vivo, we use interferon-γ and monophosphoryl lipid A to activate an innate immune response that repolarizes the hPSC-CAR-Ms to tumoricidal macrophages. Moreover, through combined activation of T cells by hPSC-CAR-Ms, we demonstrate that activating a collaborative innate-adaptive immune response can further enhance the anti-tumor effect of hPSC-CAR-Ms in vivo. Collectively, our study provides feasible methodologies that significantly improve the production and function of hPSC-CAR-Ms to support their translation into clinical applications.

Engineered CD147-CAR macrophages for enhanced phagocytosis of cancers

Chimeric antigen receptor (CAR) T cell therapy has shown promising results in hematologic malignancies, but its effectiveness in solid cancers remains challenging. Macrophages are immune cells residing within the tumor microenvironment. They can phagocytose tumor cells. Recently, CAR macrophages (CAR-M) have been a promising candidate for treating solid cancers. One of the common cancer antigens overexpressed in various types of cancer is CD147. CAR-T and NK cells targeting CD147 antigen have shown significant efficacy against hepatocellular carcinoma. Nevertheless, CAR-M targeting the CD147 molecule has not been investigated. In this study, we generated CAR targeting the CD147 molecule using the THP-1 monocytic cell line (CD147 CAR-M). The CD147 CAR-M exhibited typical macrophage characteristics, including phagocytosis of zymosan bioparticles and polarization ability toward M1 and M2 phenotypes. Furthermore, the CD147 CAR-M demonstrated enhanced anti-tumor activity against K562 and MDA-MB-231 cells without exhibiting off-target cytotoxicity against normal cells. Our research provides valuable insights into the potential of CD147 CAR-M as a promising platform for cancer immunotherapy, with applications in both hematologic malignancies and solid cancers.

Adverse events associated with chimeric antigen receptor T-cell therapy in ophthalmology: a narrative review

Chimeric antigen receptors are synthetically produced receptors engineered to engage with target cells with high specificity. These cells are created by inserting an artificial T-cell receptor into an immunoglobulin's antigen-binding region, allowing the cells to combine and target specific antigens. The use of chimeric antigen receptor (CAR) T-cell therapy has been a remarkable achievement in the field of immunotherapy, particularly in the treatment of ophthalmic tumors like retinoblastoma and uveal melanoma. However, there are some documented side effects, such as cytokine release syndrome (CRS) and immunological effector cell-associated neurotoxicity syndrome (ICANS). Additionally, ocular side effects such as blurred vision, vision impairment, and intraocular infections are also concerning and require further evaluation. This review highlights the advances made in chimeric antigen receptor (CAR) immunotherapy, including its structure and manufacture, as well as relevant clinical discoveries and associated adverse effects. By identifying the gaps in current research, this analysis provides insights into potential strategies and solutions for addressing some of the most severe side effects.

Distinct host preconditioning regimens differentially impact the antitumor potency of adoptively transferred Th17 cells

BACKGROUND

How distinct methods of host preconditioning impact the efficacy of adoptively transferred antitumor T helper cells is unknown.

METHODS

CD4+ T cells with a transgenic T-cell receptor that recognize tyrosinase-related peptide (TRP)-1 melanoma antigen were polarized to the T helper 17 (Th17) phenotype and then transferred into melanoma-bearing mice preconditioned with either total body irradiation or chemotherapy.

RESULTS

We found that preconditioning mice with a non-myeloablative dose of total body irradiation (TBI of 5 Gy) was more effective than using an equivalently dosed non-myeloablative chemotherapy (cyclophosphamide (CTX) of 200 mg/kg) at augmenting therapeutic activity of antitumor TRP-1 Th17 cells. Antitumor Th17 cells engrafted better following preconditioning with TBI and regressed large established melanoma in all animals. Conversely, only half of mice survived long-term when preconditioned with CTX and infused with anti-melanoma Th17 cells. Interleukin (IL)-17 and interferon-γ, produced by the infused Th17 cells, were detected in animals given either TBI or CTX preconditioning. Interestingly, inflammatory cytokines (granulocyte colony stimulating factor, IL-6, monocyte chemoattractant protein-1, IL-5, and keratinocyte chemoattractant) were significantly elevated in the serum of mice preconditioned with TBI versus CTX after Th17 therapy. The addition of fludarabine (FLU, 200 mg/kg) to CTX (200 mg/kg) improved the antitumor response to the same degree mediated by TBI, whereas FLU alone with Th17 therapy was ineffective.

CONCLUSIONS

Our results indicate, for the first time, that the antitumor response, persistence, and cytokine profiles resulting from Th17 therapy are impacted by the specific regimen of host preconditioning. This work is important for understanding mechanisms that promote long-lived responses by adoptive cellular therapy, particularly as CD4+ based T-cell therapies are now emerging in the clinic.

Engineering strategies to safely drive CAR T-cells into the future

Chimeric antigen receptor (CAR) T-cell therapy has proven a breakthrough in cancer treatment in the last decade, giving unprecedented results against hematological malignancies. All approved CAR T-cell products, as well as many being assessed in clinical trials, are generated using viral vectors to deploy the exogenous genetic material into T-cells. Viral vectors have a long-standing clinical history in gene delivery, and thus underwent iterations of optimization to improve their efficiency and safety. Nonetheless, their capacity to integrate semi-randomly into the host genome makes them potentially oncogenic via insertional mutagenesis and dysregulation of key cellular genes. Secondary cancers following CAR T-cell administration appear to be a rare adverse event. However several cases documented in the last few years put the spotlight on this issue, which might have been underestimated so far, given the relatively recent deployment of CAR T-cell therapies. Furthermore, the initial successes obtained in hematological malignancies have not yet been replicated in solid tumors. It is now clear that further enhancements are needed to allow CAR T-cells to increase long-term persistence, overcome exhaustion and cope with the immunosuppressive tumor microenvironment. To this aim, a variety of genomic engineering strategies are under evaluation, most relying on CRISPR/Cas9 or other gene editing technologies. These approaches are liable to introduce unintended, irreversible genomic alterations in the product cells. In the first part of this review, we will discuss the viral and non-viral approaches used for the generation of CAR T-cells, whereas in the second part we will focus on gene editing and non-gene editing T-cell engineering, with particular regard to advantages, limitations, and safety. Finally, we will critically analyze the different gene deployment and genomic engineering combinations, delineating strategies with a superior safety profile for the production of next-generation CAR T-cell.

Single-cell analysis of the survival mechanisms of fratricidal CAR-T targeting of T cell malignancies

Chimeric antigen receptor T (CAR-T) cell therapy targeting T cell tumors still faces many challenges, one of which is its fratricide due to the target gene expressed on CAR-T cells. Despite this, these CAR-T cells can be expanded in vitro by extending the culture time and effectively eliminating malignant T cells. However, the mechanisms underlying CAR-T cell survival in cell subpopulations, the molecules involved, and their regulation are still unknown. We performed single-cell transcriptome profiling to investigate the fratricidal CAR-T products (CD26 CAR-Ts and CD44v6 CAR-Ts) targeting T cells, taking CD19 CAR-Ts targeting B cells from the same donor as a control. Compared with CD19 CAR-Ts, fratricidal CAR-T cells exhibit no unique cell subpopulation, but have more exhausted T cells, fewer cytotoxic T cells, and more T cell receptor (TCR) clonal amplification. Furthermore, we observed that fratricidal CAR-T cell survival was accompanied by target gene expression. Gene expression results suggest that fratricidal CAR-T cells may downregulate their human leukocyte antigen (HLA) molecules to evade T cell recognition. Single-cell regulatory network analysis and suppression experiments revealed that exhaustion mediated by critical regulatory factors may contribute to fratricidal CAR-T cell survival. Together, these data provide valuable and first-time insights into the survival of fratricidal CAR-T cells.

B7-H3-Targeting Chimeric Antigen Receptors Epstein-Barr Virus-specific T Cells Provides a Tumor Agnostic Off-The-Shelf Therapy Against B7-H3-positive Solid Tumors

Encouraged by the observations of significant B7-H3 protein overexpression in many human solid tumors compared to healthy tissues, we directed our focus towards targeting B7-H3 using chimeric antigen receptor (CAR) T cells. We utilized a nanobody as the B7-H3-targeting domain in our CAR construct to circumvent the stability issues associated with single-chain variable fragment-based domains. In efforts to expand patient access to CAR T-cell therapy, we engineered our nanobody-based CAR into human Epstein-Barr virus-specific T cells (EBVST), offering a readily available off-the-shelf treatment. B7H3.CAR-armored EBVSTs demonstrated potent in vitro and in vivo activities against multiple B7-H3-positive human tumor cell lines and patient-derived xenograft models. Murine T cells expressing a murine equivalent of our B7H3.CAR exhibited no life-threatening toxicities in immunocompetent mice bearing syngeneic tumors. Further in vitro evaluation revealed that while human T, B, and natural killer cells were unaffected by B7H3.CAR EBVSTs, monocytes were targeted because of upregulation of B7-H3. Such targeting of myeloid cells, which are key mediators of cytokine release syndrome (CRS), contributed to a low incidence of CRS in humanized mice after B7H3.CAR EBVST treatment. Notably, we showed that B7H3.CAR EBVSTs can target B7-H3-expressing myeloid-derived suppressor cells (MDSC), thereby mitigating MDSC-driven immune suppression. In summary, our data demonstrate that our nanobody-based B7H3.CAR EBVSTs are effective as an off-the-shelf therapy for B7-H3-positive solid tumors. These cells also offer an avenue to modulate the immunosuppressive tumor microenvironment, highlighting their promising clinical potential in targeting solid tumors.

SIGNIFICANCE

Clinical application of EBVSTs armored with B7-H3-targeting CARs offer an attractive solution to translate off-the-shelf CAR T cells as therapy for solid tumors.

Advanced Practice Nursing and CAR-T Cell Therapy: Opportunities, Challenges and Future Directions

OBJECTIVES

Chimeric antigen receptor (CAR)-T cell therapy is a new treatment for patients with myeloma and other B cell malignancies where advanced practice nurses (APN) can make a great contribution. The aim of this review is to identify key aspects of current literature relevant to APNs working with this population.

METHODS

Discussion of selected peer-reviewed literature and best practice guidelines found through electronic database searches (CINAHL, MEDLINE).

RESULTS

Although few APN roles in CAR-T cell therapy have been published to date, recent research suggests that the APN is central to the care of these patients. They are essential for continuity of care and navigation through the treatment process, providing an important and consistent point of contact for patients' and carers' anxieties and uncertainties. APNs play a central role in symptom management, as they constantly incorporate new experience and scientific findings into the refinement of existing protocols. The continuum of care extends far beyond the inpatient stay and addresses symptoms that may persist long after cytokine release syndrome and neurotoxicity have resolved. The APN may therefore make a relevant contribution to patients' health-related quality of life, given its likely correlation with the dynamics and intensity of treatment-related symptoms. The APN also takes on a leadership role in the treatment team.

CONCLUSIONS

APNs use all core competencies to sustainably support and empower patients and caregivers. This is achieved through counseling and education, in addition to identifying, developing, and implementing evidence-based symptom management. They play pivotal roles in introducing new CAR-T cell products, educating teams, and advancing their role through APN networks. Finally, APNs are integral members of multiprofessional teams, supporting colleagues in ethically challenging patient situations.

IMPLICATIONS FOR NURSING PRACTICE

APNs in the field of CAR-T cell therapy make an important contribution to the continuous care of patients, caregivers, and treatment teams.

CAR T cells redirected to B7-H3 for pediatric solid tumors: Current status and future perspectives

Despite intensive therapies, pediatric patients with relapsed or refractory solid tumors have poor outcomes and need novel treatments. Immune therapies offer an alternative to conventional treatment options but require the identification of differentially expressed antigens to direct antitumor activity to sites of disease. B7-H3 (CD276) is an immune regulatory protein that is expressed in a range of malignancies and has limited expression in normal tissues. B7-H3 is highly expressed in pediatric solid tumors including osteosarcoma, rhabdomyosarcoma, Ewing sarcoma, Wilms tumor, neuroblastoma, and many rare tumors. In this article we review B7-H3-targeted chimeric antigen receptor (B7-H3-CAR) T cell therapies for pediatric solid tumors, reporting preclinical development strategies and outlining the landscape of active pediatric clinical trials. We identify challenges to the success of CAR T cell therapy for solid tumors including localizing to and penetrating solid tumor sites, evading the hostile tumor microenvironment, supporting T cell expansion and persistence, and avoiding intrinsic tumor resistance. We highlight strategies to overcome these challenges and enhance the effect of B7-H3-CAR T cells, including advanced CAR T cell design and incorporation of combination therapies.

Chimeric antigen receptor T-cell therapy in childhood acute myeloid leukemia: how far are we from a clinical application?

Recurrent and/or refractory (R/R) pediatric acute myeloid leukemia (AML) remains a recalcitrant disease with poor outcomes. Cell therapy with genetically modified immune effector cells holds the promise to improve outcomes for R/R AML since it relies on cytotoxic mechanisms that are distinct from chemotherapeutic agents. While T cells expressing chimeric antigen receptors (CAR T cells) showed significant anti-AML activity in preclinical models, early phase clinical studies have demonstrated limited activity, irrespective of the targeted AML antigen. Lack of efficacy is most likely multifactorial, including: (i) a limited array of AML-specific targets and target antigen heterogeneity; (ii) the aggressive nature of R/R AML and heavy pretreatment of patients; (iii) T-cell product manufacturing, and (iv) limited expansion and persistence of the CAR T cells, which is in part driven by the immunosuppressive AML microenvironment. Here we review the results of early phase clinical studies with AML-specific CAR T cells, and avenues investigators are exploring to improve their effector function.

Chimeric antigen receptor-modified macrophages ameliorate liver fibrosis in preclinical models

BACKGROUND & AIMS

Treatments directly targeting fibrosis remain limited. Given the unique intrinsic features of macrophages and their capacity to engraft in the liver, we genetically engineered bone marrow-derived macrophages with a chimeric antigen receptor (CAR) to direct their phagocytic activity against hepatic stellate cells (HSCs) in multiple mouse models. This study aimed to demonstrate the therapeutic efficacy of CAR macrophages (CAR-Ms) in mouse models of fibrosis and cirrhosis and to elucidate the underlying mechanisms.

METHODS

uPAR expression was studied in patients with fibrosis/cirrhosis and in murine models of liver fibrosis, including mice treated with carbon tetrachloride, a 5-diethoxycarbonyl-1, 4-dihydrocollidine diet, or a high-fat/cholesterol/fructose diet. The safety and efficacy of CAR-Ms were evaluated in vitro and in vivo.

RESULTS

Adoptive transfer of CAR-Ms resulted in a significant reduction in liver fibrosis and the restoration of function in murine models of liver fibrosis. CAR-Ms modulated the hepatic immune microenvironment to recruit and modify the activation of endogenous immune cells to drive fibrosis regression. These CAR-Ms were able to recruit and present antigens to T cells and mount specific antifibrotic T-cell responses to reduce fibroblasts and liver fibrosis in mice.

CONCLUSION

Collectively, our findings demonstrate the potential of using macrophages as a platform for CAR technology to provide an effective treatment option for liver fibrosis. CAR-Ms might be developed for treatment of patients with liver fibrosis.

IMPACT AND IMPLICATIONS

Liver fibrosis is an incurable condition that afflicts millions of people globally. Despite the clear clinical need, therapies for liver fibrosis are limited. Our findings provide the first preclinical evidence that chimeric antigen receptor (CAR)-macrophages (CAR-Ms) targeting uPAR can attenuate liver fibrosis and cirrhosis. We show that macrophages expressing this uPAR CAR exert a direct antifibrotic effect and elicit a specific T-cell response that augments the immune response against liver fibrosis. These findings demonstrate the potential of using CAR-Ms as an effective cell-based therapy for the treatment of liver fibrosis.

T cell exhaustion initiates tertiary lymphoid structures and turbocharges cancer-immunity cycle

Immune therapies represented by immune checkpoint blockade (ICB) have significantly transformed cancer treatment. However, the effectiveness of these treatments depends on the status of T cells. T cell exhaustion, characterized by diminished effector function, increased expression of co-inhibitory receptors, and clonal deletion, emerges as a hypofunctional state resulting from chronic exposure to antigens, posing an obstacle to ICB therapy. Several studies have deeply explored T cell exhaustion, providing innovative insights and correlating T cell exhaustion with tertiary lymphoid structures (TLS) formation. TLS, lymphocyte aggregates formed in non-lymphoid tissues amid chronic inflammation, serve as pivotal reservoirs for anti-tumour immunity. Here, we underscore the pivotal role of T cell exhaustion as a signalling mechanism in reinvigorating anti-tumour immunity by turbocharging cancer-immunity (CI) cycle, particularly when tumour becomes unmanageable. Building upon this concept, we summarize emerging immunotherapeutic strategies aimed at enhancing the response rate to ICB therapy and improving patient prognosis.

Revolutionizing tumor immunotherapy: unleashing the power of progenitor exhausted T cells

In exploring persistent infections and malignancies, a distinctive subgroup of CD8+ T cells, progenitor exhausted CD8+ T (Tpex) cells, has been identified. These Tpex cells are notable for their remarkable self-renewal and rapid proliferation abilities. Recent strides in immunotherapy have demonstrated that Tpex cells expand and differentiate into responsive exhausted CD8+ T cells, thus underscoring their critical role in the immunotherapeutic retort. Clinical examinations have further clarified a robust positive correlation between the proportional abundance of Tpex cells and enhanced clinical prognosis. Tpex cells have found noteworthy applications in the formulation of inventive immunotherapeutic approaches against tumors. This review describes the functions of Tpex cells in the tumor milieu, particularly their potential utility in tumor immunotherapy. Precisely directing Tpex cells may be essential to achieving successful outcomes in immunotherapy against tumors.

In silico study of heterogeneous tumour-derived organoid response to CAR T-cell therapy

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapy for treating cancers. This method consists in modifying the patients' T-cells to directly target antigen-presenting cancer cells. One of the barriers to the development of this type of therapies, is target antigen heterogeneity. It is thought that intratumour heterogeneity is one of the leading determinants of therapeutic resistance and treatment failure. While understanding antigen heterogeneity is important for effective therapeutics, a good therapy strategy could enhance the therapy efficiency. In this work we introduce an agent-based model (ABM), built upon a previous ABM, to rationalise the outcomes of different CAR T-cells therapies strategies over heterogeneous tumour-derived organoids. We found that one dose of CAR T-cell therapy should be expected to reduce the tumour size as well as its growth rate, however it may not be enough to completely eliminate it. Moreover, the amount of free CAR T-cells (i.e. CAR T-cells that did not kill any cancer cell) increases as we increase the dosage, and so does the risk of side effects. We tested different strategies to enhance smaller dosages, such as enhancing the CAR T-cells long-term persistence and multiple dosing. For both approaches an appropriate dosimetry strategy is necessary to produce "effective yet safe" therapeutic results. Moreover, an interesting emergent phenomenon results from the simulations, namely the formation of a shield-like structure of cells with low antigen expression. This shield turns out to protect cells with high antigen expression. Finally we tested a multi-antigen recognition therapy to overcome antigen escape and heterogeneity. Our studies suggest that larger dosages can completely eliminate the organoid, however the multi-antigen recognition increases the risk of side effects. Therefore, an appropriate small dosages dosimetry strategy is necessary to improve the outcomes. Based on our results, it is clear that a proper therapeutic strategy could enhance the therapies outcomes. In that direction, our computational approach provides a framework to model treatment combinations in different scenarios and to explore the characteristics of successful and unsuccessful treatments.

IVT-mRNA reprogramming of myeloid cells for cancer immunotherapy

In the past decade, in vitro transcribed messenger RNAs (IVT-mRNAs) have emerged as promising therapeutic molecules. The clinical success of COVID-19 mRNA vaccines developed by Pfizer-BioNTech and Moderna, have demonstrated that IVT-mRNAs can be safely and successfully used in a clinical setting, and efforts are underway to develop IVT-mRNAs for therapeutic applications. Current applications of mRNA-based therapy have been focused on (1) mRNA vaccines for infectious diseases and cancer treatment; (2) protein replacement therapy; (3) gene editing therapy; and (4) cell-reprogramming therapies. Due to the recent clinical progress of cell-based immunotherapies, the last direction-the use of IVT-mRNAs as a therapeutic approach to program immune cells for the treatment of cancer has received extensive attention from the cancer immunotherapy field. Myeloid cells are important components of our immune system, and they play critical roles in mediating disease progression and regulating immunity against diseases. In this chapter, we discussed the progress of using IVT-mRNAs as a therapeutic approach to program myeloid cells against cancer and other immune-related diseases. Towards this direction, we first reviewed the pharmacology of IVT-mRNAs and the biology of myeloid cells as well as myeloid cell-targeting therapeutics. We then presented a few cases of current IVT-mRNA-based approaches to target and reprogram myeloid cells for disease treatment and discussed the advantages and limitations of these approaches. Finally, we presented our considerations in designing mRNA-based approaches to target myeloid cells for disease treatment.

Safety and biological outcomes following a phase 1 trial of GD2-specific CAR-T cells in patients with GD2-positive metastatic melanoma and other solid cancers

BACKGROUND

Chimeric antigen receptor (CAR) T cell therapies specific for the CD19 and B-cell maturation antigen have become an approved standard of care worldwide for relapsed and refractory B-cell malignancies. If CAR-T cell therapy for non-hematological malignancies is to achieve the same stage of clinical development, then iterative early-phase clinical testing can add value to the clinical development process for evaluating CAR-T cell products containing different CAR designs and manufactured under differing conditions.

METHODS

We conducted a phase 1 trial of third-generation GD2-specific CAR-T cell therapy, which has previously been tested in neuroblastoma patients. In this study, the GD2-CAR-T therapy was evaluated for the first time in metastatic melanoma patients in combination with BRAF/MEK inhibitor therapy, and as a monotherapy in patients with colorectal cancer and a patient with fibromyxoid sarcoma. Feasibility and safety were determined and persistence studies, multiplex cytokine arrays on sera and detailed immune phenotyping of the original CAR-T products, the circulating CAR-T cells, and, in select patients, the tumor-infiltrating CAR-T cells were performed.

RESULTS

We demonstrate the feasibility of manufacturing CAR-T products at point of care for patients with solid cancer and show that a single intravenous infusion was well tolerated with no dose-limiting toxicities or severe adverse events. In addition, we note significant improvements in CAR-T cell immune phenotype, and expansion when a modified manufacturing procedure was adopted for the latter 6 patients recruited to this 12-patient trial. We also show evidence of CAR-T cell-mediated immune activity and in some patients expanded subsets of circulating myeloid cells after CAR-T cell therapy.

CONCLUSIONS

This is the first report of third-generation GD2-targeting CAR-T cells in patients with metastatic melanoma and other solid cancers such as colorectal cancer, showing feasibility, safety and immune activity, but limited clinical effect.

TRIAL REGISTRATION NUMBER

ACTRN12613000198729.

Discovery of immunotherapy targets for pediatric solid and brain tumors by exon-level expression

Immunotherapy with chimeric antigen receptor T cells for pediatric solid and brain tumors is constrained by available targetable antigens. Cancer-specific exons present a promising reservoir of targets; however, these have not been explored and validated systematically in a pan-cancer fashion. To identify cancer specific exon targets, here we analyze 1532 RNA-seq datasets from 16 types of pediatric solid and brain tumors for comparison with normal tissues using a newly developed workflow. We find 2933 exons in 157 genes encoding proteins of the surfaceome or matrisome with high cancer specificity either at the gene (n = 148) or the alternatively spliced isoform (n = 9) level. Expression of selected alternatively spliced targets, including the EDB domain of fibronectin 1, and gene targets, such as COL11A1, are validated in pediatric patient derived xenograft tumors. We generate T cells expressing chimeric antigen receptors specific for the EDB domain or COL11A1 and demonstrate that these have antitumor activity. The full target list, explorable via an interactive web portal ( https://cseminer.stjude.org/ ), provides a rich resource for developing immunotherapy of pediatric solid and brain tumors using gene or AS targets with high expression specificity in cancer.

CAR-macrophage versus CAR-T for solid tumors: The race between a rising star and a superstar

Adoptive cell therapy (ACT) has been demonstrated to be one of the most promising cancer immunotherapy strategies due to its active antitumor capabilities in vivo. Engineering T cells to overexpress chimeric antigen receptors (CARs), for example, has shown potent efficacy in the therapy of some hematologic malignancies. However, the efficacy of chimeric antigen receptor T cell (CAR-T) therapy against solid tumors is still limited due to the immunosuppressive tumor microenvironment (TME) of solid tumors, difficulty in infiltrating tumor sites, lack of tumor-specific antigens, antigen escape, and severe side effects. In contrast, macrophages expressing CARs (CAR-macrophages) have emerged as another promising candidate in immunotherapy, particularly for solid tumors. Now at its nascent stage (with only one clinical trial progressing), CAR-macrophage still shows inspiring potential advantages over CAR-T in treating solid tumors, including more abundant antitumor mechanisms and better infiltration into tumors. In this review, we discuss the relationships and differences between CAR-T and CAR-macrophage therapies in terms of their CAR structures, antitumor mechanisms, challenges faced in treating solid tumors, and insights gleaned from clinical trials and practice for solid tumors. We especially highlight the potential advantages of CAR-macrophage therapy over CAR-T for solid tumors. Understanding these relationships and differences provides new insight into possible optimization strategies of both these two therapies in solid tumor treatment.

The new era of immunological treatment, last updated and future consideration of CAR T cell-based drugs

Cancer treatment is one of the fundamental challenges in clinical setting, especially in relapsed/refractory malignancies. The novel immunotherapy-based treatments bring new hope in cancer therapy and achieve various treatment successes. One of the distinguished ways of cancer immunotherapy is adoptive cell therapy, which utilizes genetically modified immune cells against cancer cells. Between different methods in ACT, the chimeric antigen receptor T cells have more investigation and introduced a promising way to treat cancer patients. This technology progressed until it introduced six US Food and Drug Administration-approved CAR T cell-based drugs. These drugs act against hematological malignancies appropriately and achieve exciting results, so they have been utilized widely in cell therapy clinics. In this review, we introduce all CAR T cells-approved drugs based on their last data and investigate them from all aspects of pharmacology, side effects, and compressional. Also, the efficacy of drugs, pre- and post-treatment steps, and expected side effects are introduced, and the challenges and new solutions in CAR T cell therapy are in the last speech.

Combination of T cell-redirecting strategies with a bispecific antibody blocking TGF-β and PD-L1 enhances antitumor responses

T cell-based immunotherapies for solid tumors have not achieved the clinical success observed in hematological malignancies, partially due to the immunosuppressive effect promoted by the tumor microenvironment, where PD-L1 and TGF-β play a pivotal role. However, durable responses to immune checkpoint inhibitors remain limited to a minority of patients, while TGF-β inhibitors have not reached the market yet. Here, we describe a bispecific antibody for dual blockade of PD-L1 and TFG-β, termed AxF (scFv)2, under the premise that combination with T cell redirecting strategies would improve clinical benefit. The AxF (scFv)2 antibody was well expressed in mammalian and yeast cells, bound both targets and inhibited dose-dependently the corresponding signaling pathways in luminescence-based cellular reporter systems. Moreover, combined treatment with trispecific T-cell engagers (TriTE) or CAR-T cells significantly boosted T cell activation status and cytotoxic response in breast, lung and colorectal (CRC) cancer models. Importantly, the combination of an EpCAMxCD3×EGFR TriTE with the AxF (scFv)2 delayed CRC tumor growth in vivo and significantly enhanced survival compared to monotherapy with the trispecific antibody. In summary, we demonstrated the feasibility of concomitant blockade of PD-L1 and TGF-β by a single molecule, as well as its therapeutic potential in combination with different T cell redirecting agents to overcome tumor microenvironment-mediated immunosuppression.

A high-content screen of FDA approved drugs to enhance CAR T cell function: ingenol-3-angelate improves B7-H3-CAR T cell activity by upregulating B7-H3 on the target cell surface via PKCα activation

BACKGROUND

CAR T cell therapy is a promising approach to improve outcomes and decrease toxicities for patients with cancer. While extraordinary success has been achieved using CAR T cells to treat patients with CD19-positive malignancies, multiple obstacles have so far limited the benefit of CAR T cell therapy for patients with solid tumors. Novel manufacturing and engineering approaches show great promise to enhance CAR T cell function against solid tumors. However, similar to single agent chemotherapy approaches, CAR T cell monotherapy may be unable to achieve high cure rates for patients with difficult to treat solid tumors. Thus, combinatorial drug plus CAR T cell approaches are likely required to achieve widespread clinical success.

METHODS

We developed a novel, confocal microscopy based, high-content screen to evaluate 1114 FDA approved drugs for the potential to increase expression of the solid tumor antigen B7-H3 on the surface of osteosarcoma cells. Western blot, RT-qPCR, siRNA knockdown and flow cytometry assays were used to validate screening results and identify mechanisms of drug-induced B7-H3 upregulation. Cytokine and cytotoxicity assays were used to determine if drug pre-treatment enhanced B7-H3-CAR T cell effector function.

RESULTS

Fifty-five drugs were identified to increase B7-H3 expression on the surface of LM7 osteosarcoma cells using a novel high-content, high-throughput screen. One drug, ingenol-3-angelate (I3A), increased B7-H3 expression by up to 100%, and was evaluated in downstream experiments. Validation assays confirmed I3A increased B7-H3 expression in a biphasic dose response and cell dependent fashion. Mechanistic studies demonstrated that I3A increased B7-H3 (CD276) mRNA, total protein, and cell surface expression via protein kinase C alpha activation. Functionally, I3A induced B7-H3 expression enhanced B7-H3-CAR T cell function in cytokine production and cytotoxicity assays.

CONCLUSIONS

This study demonstrates a novel high-content and high-throughput screen can identify drugs to enhance CAR T cell activity. This and other high-content technologies will pave the way to develop clinical trials implementing rational drug plus CAR T cell combinatorial therapies. Importantly, the technique could also be repurposed for an array of basic and translational research applications where drugs are needed to modulate cell surface protein expression.

CAR-T Cell Therapy: Advances in Kidney-Related Diseases

Background

Chimeric antigen receptor (CAR)-T cell therapy represents a significant advancement in the field of immunotherapy, providing targeted eradication of abnormal cells through the recognition between CAR and target antigens. This approach has garnered considerable attention due to its promising results in the clinical treatment of hematological malignancies and autoimmune diseases. As the focus shifts toward exploring novel targets and expanding the application of CAR-T cell therapy to solid tumors, including renal malignancies, researchers are pushing the boundaries of this innovative treatment. However, it is crucial to address the observed comorbidities associated with CAR-T cell therapy, particularly nephrotoxicity, due to the superseding release of cytokines and impairment of normal tissue.

Summary

Our review discusses the research strategies and nephrotoxicity related to CAR-T cell therapy in various kidney-related diseases and provides insights into enhancing investigation and optimization.

Key Messages

CAR-T cell therapy has captured the attention of researchers and clinicians in the treatment of renal malignancies, multiple myeloma, systemic lupus erythematosus, and acquired immunodeficiency syndrome, which may lead to potential nephrotoxicity as they involve primary or secondary kidney complications. Understanding and summarizing the current research progress of CAR-T cell therapies can provide valuable insights into novel targets and combinations to optimize research models and enhance their clinical value.