IL-21-armored B7H3 CAR-iNKT cells exert potent antitumor effects

Interleukin-enhanced CAR-engineered immune cells in tumor immunotherapy: current insights and future perspectives

Despite the remarkable clinical success of chimeric antigen receptor (CAR)-T cell therapy in hematologic malignancies, the therapeutic efficacy of conventional second-generation CAR-T cells in treating solid tumors remains suboptimal, primarily due to three major biological barriers: (1) the immunosuppressive tumor microenvironment (TME), (2) inadequate tumor infiltration capacity, and (3) T cell exhaustion mechanisms. To overcome these limitations, innovative fourth-generation "armored" CAR-T cell platforms have been engineered with integrated cytokine-secreting modules designed to potentiate anti-tumor responses through localized immunomodulation. These advanced cellular therapeutics achieve targeted delivery of various immunostimulatory cytokines directly within the TME, thereby orchestrating three critical therapeutic effects: (I) remodeling of the immunosuppressive niche, (II) enhancement of immune cell persistence, and (III) neutralization of immunosuppressive signaling networks. This comprehensive review systematically examines the translational applications of cytokine-secreting CAR-engineered immune cells, including CAR-T, CAR-NK, and CAR-iNKT cell platforms, in solid tumor immunotherapy, with particular emphasis on multiple classes of immunomodulatory cytokines that enhance cytotoxic potential, promote immune cell survival, and counteract TME-mediated immunosuppression. We critically evaluate preclinical and clinical evidence demonstrating the therapeutic efficacy of cytokine-armed CAR-engineered cells across various tumor models, including hematological malignancies, glioblastoma, and neuroblastoma. Furthermore, this review addresses current translational challenges, particularly cytokine-associated toxicity profiles and innovative strategies for achieving spatiotemporal control of cytokine release, while discussing their potential implications for advancing clinical outcomes in solid tumor immunotherapy.

Generating allogeneic CAR-NKT cells for off-the-shelf cancer immunotherapy with genetically engineered HSP cells and feeder-free differentiation culture

The clinical potential of current chimeric antigen receptor-engineered T (CAR-T) cell therapy is hampered by its autologous nature that poses considerable challenges in manufacturing, costs and patient selection. This spurs demand for off-the-shelf therapies. Here we introduce an ex vivo feeder-free culture method to differentiate gene-engineered hematopoietic stem and progenitor (HSP) cells into allogeneic invariant natural killer T (AlloNKT) cells and their CAR-armed derivatives (AlloCAR-NKT cells). We include detailed information on lentivirus generation and titration, as well as the five stages of ex vivo culture required to generate AlloCAR-NKT cells, including HSP cell engineering, HSP cell expansion, NKT cell differentiation, NKT cell deep differentiation and NKT cell expansion. In addition, we describe procedures for evaluating the pharmacology, antitumor efficacy and mechanism of action of AlloCAR-NKT cells. It takes ~2 weeks to generate and titrate lentiviruses and ~6 weeks to generate mature AlloCAR-NKT cells. Competence with human stem cell and T cell culture, gene engineering and flow cytometry is required for optimal results.

Efficacy of MET-targeting CAR T cells against glioblastoma patient-derived xenograft models

BACKGROUND

Genetic alteration of the MET receptor tyrosine kinase frequently occurs in glioblastoma (GBM). Clinically, bevacizumab treatment results in MET signaling activation, leading to GBM recurrence with a more malignant phenotype. While MET has been a promising therapeutic target, MET inhibitors have not been successful in treating GBM patients. MET-directed chimeric antigen receptor (CAR) T cells hold the promise of targeting MET-positive GBM regardless of genetic alterations or kinase activity.

METHODS

GBM patient-derived xenografts (PDX) harboring MET amplification (METamp) or PTPRZ-MET fusion (ZM) were propagated in vivo followed by glioma stem cell (GSC) isolation. Cell-based assays were used for comparing GSC survival in response to MET inhibitors and CAR T cells. Multi-panel cytokine release was analyzed to profile MET-CAR T cell activation during co-culture with GBM. Orthotopic tumor growth and real-time imaging were performed to evaluate MET-CAR T cell therapeutic efficacy in vivo.

RESULTS

Although GBM are heterogeneous tumors, neuro-sphere cells isolated from METamp or ZM fusion PDX tumors showed universal cognate genetic MET alteration along with GSC markers such as SOX2 and nestin. Both METamp and ZM fusion tumors showed MET overexpression but only the METamp cells presented activated MET signaling which was vulnerable to MET inhibitors. In contrast, MET-CAR T cells specifically inhibited all MET-positive tumor growth regardless of MET activation status.

CONCLUSIONS

Whereas MET inhibitors are effective in MET-active tumors, MET-CAR T cells eradicate MET-positive GBM growth in an antigen-dependent manner, demonstrating a promising therapeutic approach for treating MET-positive GBM. MET overexpression, especially METamp and ZM fusion may be used to predefine the GBM patients for treating with MET-CAR T cell therapy.

Engineering an in vivo charging station for CAR-redirected invariant natural killer T cells to enhance cancer therapy

Invariant natural killer T (iNKT) cells are a distinct subset of T lymphocytes that possess unique properties making them highly suitable for addressing the challenges of solid tumor immunotherapy. Unlike conventional T cells, which are restricted by polymorphic major histocompatibility complex (MHC) molecules and recognize peptide antigens, iNKT cells are restricted by the non-polymorphic CD1d molecule and respond to lipid antigens. Chimeric antigen receptor (CAR)-redirected iNKT (CAR-iNKT) cells represent a significant advancement in cancer immunotherapy. However, optimizing sustained activation and long-term persistence of CAR-iNKT cells remains a critical need for effective solid tumor treatment. To address these limitations, we develop the iNKT cell-targeted microparticle recruitment and activation system (iMRAS), a biomimetic platform designed to enhance iNKT cell functionality through localized immunostimulation in vivo. This biomimetic platform is designed to function as an in vivo "charging station" containing chemotactic and activation signals for the recruitment, activation, and expansion of CAR-iNKT cells, leading to more effective tumor killing and longer persistence of CAR-iNKT cells, as demonstrated in the therapy of lymphoma and melanoma. Through its biomimetic design and localized immunostimulatory effects, iMRAS helps overcome the limitations of current therapies for solid tumors, establishing a robust platform for enhancing systemic CAR-iNKT cell-mediated immunotherapy.

Interleukin-21 engineering enhances CD19-specific CAR-NK cell activity against B-cell lymphoma via enriched metabolic pathways

BACKGROUND

NK cells engineered to express interleukin-15 (IL-15) and a CD19-targeted chimeric antigen receptor (CAR) have been used to treat patients with relapsed and/or refractory B cell malignances, demonstrating encouraging outcomes and favorable safety profile. However, the effect of IL-21 in CAR-NK cell therapy remains unknown.

METHODS

CD19-specific CAR with 4-1BB costimulatory domain and cytokine IL-21 or IL-15 was constructed and transduced into peripheral blood (PB)-derived NK cells to produce CD19-CAR-IL21 NK cells (CAR-21) or CD19-CAR-IL15 NK cells (CAR-15), respectively. The phenotypic profile, transcriptomic characteristics, functionality and anti-tumor activity of CAR-21 NK cells and CAR-15 NK cells were compared.

RESULTS

Compared with CAR-NK cells co-expressing IL-15, CAR-NK cells co-expressing IL-21 exhibited significantly increased IFN-γ, TNF-α and Granzyme B production, as well as degranulation, in response to CD19+ Raji lymphoma cells, resulting in enhanced cytotoxic activity upon repetitive tumor stimulation. Furthermore, IL-21 co-expression improved the in vivo persistence of CAR-NK cells and significantly suppressed tumor growth in a xenograft Raji lymphoma murine model, leading to prolonged survival of CD19+ tumor-bearing mice. RNA sequencing revealed that CAR-21 NK cells have a distinct transcriptomic signature characterized by enriched in cytokine, cytotoxicity, and metabolic related signaling, when compared with CAR-15 NK or CAR NK cells.

CONCLUSIONS

This study demonstrated that CD19-specific CAR-NK cells engineered to express IL-21 exhibit superior persistence and anti-tumor activity against CD19+ tumor compared to CAR-NK cells co-expressing IL-15, which might be a promising therapeutic strategy for treating patients with relapse or refractory B cell malignances.

Chimeric Antigen Receptor Cell Therapy: Empowering Treatment Strategies for Solid Tumors

Chimeric antigen receptor-T (CAR-T) cell therapy has demonstrated impressive efficacy in the treatment of blood cancers; however, its effectiveness against solid tumors has been significantly limited. The differences arise from a range of difficulties linked to solid tumors, including an unfriendly tumor microenvironment, variability within the tumors, and barriers to CAR-T cell infiltration and longevity at the tumor location. Research shows that the reasons for the decreased effectiveness of CAR-T cells in treating solid tumors are not well understood, highlighting the ongoing need for strategies to address these challenges. Current strategies frequently incorporate combinatorial therapies designed to boost CAR-T cell functionality and enhance their capacity to effectively target solid tumors. However, these strategies remain in the testing phase and necessitate additional validation to assess their potential benefits. CAR-NK (natural killer), CAR-iNKT (invariant natural killer T), and CAR-M (macrophage) cell therapies are emerging as promising strategies for the treatment of solid tumors. Recent studies highlight the construction and optimization of CAR-NK cells, emphasizing their potential to overcome the unique challenges posed by the solid tumor microenvironment, such as hypoxia and metabolic barriers. This review focuses on CAR cell therapy in the treatment of solid tumors.

CAR-iNKT cell therapy: mechanisms, advantages, and challenges

In recent years, chimeric antigen receptor (CAR) T-cell therapy has emerged as a groundbreaking approach in cancer immunotherapy. Particularly in hematologic malignancies, such as B-cell acute lymphoblastic leukemia (B-ALL), B cell lymphomas and multiple myeloma. CAR-T therapy has demonstrated remarkable clinical efficacy, leading to the approval of several CAR-T cell products and offering significant benefits to numerous leukemia patients. Despite these successes, the application of CAR-T cells in solid tumors remains limited due to significant challenges, including immunosuppressive tumor microenvironments, heterogeneous antigen expression, and treatment-associated toxicities. In parallel with CAR-T development, researchers are investigating other immune cell platforms to overcome these obstacles. Among these, invariant natural killer T (iNKT) cells have garnered increasing attention for their unique immunological properties. Unlike conventional T cells, iNKT cells are a subset of T lymphocytes characterized by the expression of a semi-invariant T-cell receptor (TCR) that recognizes lipid antigens presented by CD1d molecules. This distinctive antigen recognition mechanism enables iNKT cells to bridge innate and adaptive immunity, granting them potent antitumor activity and the ability to modulate the tumor microenvironment. Additionally, iNKT cells exhibit intrinsic resistance to exhaustion and an enhanced ability to infiltrate solid tumors compared to traditional T cells. Building on these properties, researchers are leveraging CAR technology to enhance iNKT cell tumor-targeting capabilities, aiming to overcome barriers encountered in solid tumor therapy. This review provides an in-depth discussion of the application and therapeutic potential of CAR-iNKT cells in cancer immunotherapy, with a focus on their advantages over conventional CAR-T cells and their role in addressing the challenges of solid tumor treatment.

Traversing the bench to bedside journey for iNKT cell therapies

Invariant natural killer T (iNKT) cells are immune cells that harness properties of both the innate and adaptive immune system and exert multiple functions critical for the control of various diseases. Prevention of graft-versus-host disease (GVHD) by iNKT cells has been demonstrated in mouse models and in correlative human studies in which high iNKT cell content in the donor graft is associated with reduced GVHD in the setting of allogeneic hematopoietic stem cell transplants. This suggests that approaches to increase the number of iNKT cells in the setting of an allogeneic transplant may reduce GVHD. iNKT cells can also induce cytolysis of tumor cells, and murine experiments demonstrate that activating iNKT cells in vivo or treating mice with ex vivo expanded iNKT cells can reduce tumor burden. More recently, research has focused on testing anti-tumor efficacy of iNKT cells genetically modified to express a chimeric antigen receptor (CAR) protein (CAR-iNKT) cells to enhance iNKT cell tumor killing. Further, several of these approaches are now being tested in clinical trials, with strong safety signals demonstrated, though efficacy remains to be established following these early phase clinical trials. Here we review the progress in the field relating to role of iNKT cells in GVHD prevention and anti- cancer efficacy. Although the iNKT field is progressing at an exciting rate, there is much to learn regarding iNKT cell subset immunophenotype and functional relationships, optimal ex vivo expansion approaches, ideal treatment protocols, need for cytokine support, and rejection risk of iNKT cells in the allogeneic setting.

Advancements and challenges in developing in vivo CAR T cell therapies for cancer treatment

The Chimeric Antigen Receptor (CAR) T cell therapy has emerged as a ground-breaking immunotherapeutic approach in cancer treatment. To overcome the complexity and high manufacturing cost associated with current ex vivo CAR T cell therapy products, alternative strategies to produce CAR T cells directly in the body have been developed in recent years. These strategies involve the direct infusion of CAR genes via engineered nanocarriers or viral vectors to generate CAR T cells in situ. This review offers a comprehensive overview of recent advancements in the development of T cell-targeted CAR generation in situ. Additionally, it identifies the challenges associated with in vivo CAR T method and potential strategies to overcome these issues.

CAR-NKT Cells in Asthma: Use of NKT as a Promising Cell for CAR Therapy

NKT cells, unique lymphocytes bridging innate and adaptive immunity, offer significant potential for managing inflammatory disorders like asthma. Activating iNKT induces increasing IFN-γ, TGF-β, IL-2, and IL-10 potentially suppressing allergic asthma. However, their immunomodulatory effects, including granzyme-perforin-mediated cytotoxicity, and expression of TIM-3 and TRAIL warrant careful consideration and targeted approaches. Although CAR-T cell therapy has achieved remarkable success in treating certain cancers, its limitations necessitate exploring alternative approaches. In this context, CAR-NKT cells emerge as a promising approach for overcoming these challenges, potentially achieving safer and more effective immunotherapies. Strategies involve targeting distinct IgE-receptors and their interactions with CAR-NKT cells, potentially disrupting allergen-mast cell/basophil interactions and preventing inflammatory cytokine release. Additionally, targeting immune checkpoints like PDL-2, inducible ICOS, FASL, CTLA-4, and CD137 or dectin-1 for fungal asthma could further modulate immune responses. Furthermore, artificial intelligence and machine learning hold immense promise for revolutionizing NKT cell-based asthma therapy. AI can optimize CAR-NKT cell functionalities, design personalized treatment strategies, and unlock a future of precise and effective care. This review discusses various approaches to enhancing CAR-NKT cell efficacy and longevity, along with the challenges and opportunities they present in the treatment of allergic asthma.

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.