Synergistic therapeutic combination with a CAF inhibitor enhances CAR-NK-mediated cytotoxicity via reduction of CAF-released IL-6

An innovative strategy harnessing self-activating CAR-NK cells to mitigate TGF-β1-driven immune suppression

The dysfunction of natural killer (NK) cells, mediated by transforming growth factor β1 (TGFβ1) within the tumor microenvironment, impedes antitumor therapy and contributes to poor clinical outcomes. Our study introduces self-activating chimeric antigen receptor (CAR)-NK cells that block TGFβ1 signaling by releasing a specifically designed peptide, P6, which targets mesothelin in pancreatic tumors. P6 originates from the interaction sites between TGFβ1 and TGFβ receptor 1 and effectively disrupts TGFβ1's inhibitory signaling in NK cells. Our analysis demonstrates that P6 treatment interrupts the SMAD2/3 pathway in NK cells, mitigating TGFβ1-mediated suppression of NK cell activity, thereby enhancing their metabolic function and cytotoxic response against pancreatic tumors. These CAR-NK cells exhibit potent antitumor capabilities, as evidenced in spheroid cultures with cancer-associated fibroblasts and in vivo mouse models. Our approach marks a substantial advancement in overcoming TGFβ1-mediated immune evasion, offering a promising avenue for revolutionizing cancer immunotherapy.

Unlocking the potential of chimeric antigen receptor T cell engineering immunotherapy: Long road to achieve precise targeted therapy for hepatobiliary pancreatic cancers

Innovative therapeutic strategies are urgently needed to address the ongoing global health concern of hepatobiliary pancreatic malignancies. This review summarizes the latest and most comprehensive research of chimeric antigen receptor (CAR-T) cell engineering immunotherapy for treating hepatobiliary pancreatic cancers. Commencing with an exploration of the distinct anatomical location and the immunosuppressive, hypoxic tumor microenvironment (TME), this review critically assesses the limitations of current CAR-T therapy in hepatobiliary pancreatic cancers and proposes corresponding solutions. Various studies aim at enhancing CAR-T cell efficacy in these cancers through improving T cell persistence, enhancing antigen specificity and reducing tumor heterogeneity, also modulating the immunosuppressive and hypoxic TME. Additionally, the review examines the application of emerging nanoparticles and biotechnologies utilized in CAR-T therapy for these cancers. The results suggest that constructing optimized CAR-T cells to overcome physical barrier, manipulating the TME to relieve immunosuppression and hypoxia, designing CAR-T combination therapies, and selecting the most suitable delivery strategies, all together could collectively enhance the safety of CAR-T engineering and advance the effectiveness of adaptive cell therapy for hepatobiliary pancreatic cancers.

Nature killer cell for solid tumors: Current obstacles and prospective remedies in NK cell therapy and beyond

In recent years, cell therapy has emerged as an innovative treatment method for the management of clinical tumors following immunotherapy. Among them, Natural killer (NK) cell therapy has achieved a significant breakthrough in the treatment of hematological tumors. However, the therapeutic effectiveness of NK cells in the treatment of solid tumors remains challenging. With the progress of gene editing and culture techniques and their application to NK cell engineering, it is expected that NK cell therapy will revolutionize the treatment of solid tumors. In this review, we explore the discovery and biological properties of NK cells, their role in the tumor microenvironment, and the therapeutic strategies, clinical trials, challenges, and prospects of NK cells in the treatment of solid tumors.

The power and the promise of CAR-mediated cell immunotherapy for clinical application in pancreatic cancer

BACKGROUND

Pancreatic cancer, referred to as the "monarch of malignancies," is a neoplastic growth mostly arising from the epithelial cells of the pancreatic duct and acinar cells. This particular neoplasm has a highly unfavorable prognosis due to its marked malignancy, inconspicuous initial manifestation, challenging early detection, rapid advancement, and limited survival duration. Cellular immunotherapy is the ex vivo culture and expansion of immune effector cells, granting them the capacity to selectively target malignant cells using specialized techniques. Subsequently, these modified cells are reintroduced into the patient's organism with the purpose of eradicating tumor cells and providing therapeutic intervention for cancer.

PRESENT SITUATION

Presently, the primary cellular therapeutic modalities employed in the treatment of pancreatic cancer encompass CAR T-cell therapy, TCR T-cell therapy, NK-cell therapy, and CAR NK-cell therapy.

AIM OF REVIEW

This review provides a concise overview of the mechanisms and primary targets associated with various cell therapies. Additionally, we will explore the prospective outlook of cell therapy in the context of treating pancreatic cancer.

Chimeric antigen receptor natural killer cell therapy: A systematic review of preclinical studies for hematologic and solid malignancies

Advancements in the field of CAR-T therapy have brought about a revolution in the treatment of numerous types of cancer in the past ten years. However, despite the remarkable success achieved thus far, certain barriers impede the widespread implementation of this therapy such as intricate manufacturing processes and treatment-associated toxicities. As an alternative, chimeric antigen receptor-engineered natural killer cell (CAR-NK) therapy presents a viable opportunity for a simpler and more cost-effective "off-the-shelf" treatment option, which is likely to result in fewer adverse reactions. A total of 71 studies were included in this review. Eligible studies were searched and reviewed from the databases of PubMed, Web of Science and Scopus. Based on data extracted from articles, we concluded that CAR-NK cell efficiency can vary considerably depending on factors such as tumor model, dosage, CAR generation and expansion method. Furthermore, investigating consequences of utilizing various constructs and generations of CAR-NK cells on their anti-tumor activity examined in this review.

Crosstalk and communication of cancer-associated fibroblasts with natural killer and dendritic cells: New frontiers and unveiled opportunities for cancer immunotherapy

Natural killer (NK) cells and dendritic cells (DCs) are critical mediators of anti-cancer immune responses. In addition to their individual roles, NK cells and DCs are involved in intercellular crosstalk which is essential for the initiation and coordination of adaptive immunity against cancer. However, NK cell and DC activity is often compromised in the tumor microenvironment (TME). Recently, much attention has been paid to one of the major components of the TME, the cancer-associated fibroblasts (CAFs), which not only contribute to extracellular matrix (ECM) deposition and tumor progression but also suppress immune cell functions. It is now well established that CAFs support T cell exclusion from tumor nests and regulate their cytotoxic activity. In contrast, little is currently known about their interaction with NK cells, and DCs. In this review, we describe the interaction of CAFs with NK cells and DCs, by secreting and expressing various mediators in the TME of adult solid tumors. We also provide a detailed overview of ongoing clinical studies evaluating the targeting of stromal factors alone or in combination with immunotherapy based on immune checkpoint inhibitors. Finally, we discuss currently available strategies for the selective depletion of detrimental CAFs and for a better understanding of their interaction with NK cells and DCs.

Integrated single-cell and bulk RNA sequencing analyses identify an immunotherapy nonresponse-related fibroblast signature in gastric cancer

Factors that determine nonresponse to immune checkpoint inhibitor (ICI) remain unclear. The protumor activities of cancer-associated fibroblasts (CAFs) suggest that they are potential therapeutic targets for cancer treatment. There is, however, a lack of CAF-related signature in predicting response to immunotherapy in gastric cancer (GC). Single-cell RNA sequencing (scRNA-seq) and RNA sequencing (RNA-seq) data of GC immunotherapy were downloaded from the Gene Expression Omnibus database. Bulk RNA-seq data were obtained from The Cancer Genome Atlas. The R package 'Seurat' was used for scRNA-seq data processing. Cellular infiltration, receptor-ligand interactions, and evolutionary trajectory analysis were further explored. Differentially expressed genes affecting overall survival were obtained using the limma package. Weighted Gene Correlation Network Analysis was used to identify key modules of immunotherapy nonresponder. Prognostic model was constructed by univariate Cox and least absolute contraction and selection operator analysis using the intersection of activated fibroblast genes (AFGs) with key module genes. The differences in clinicopathological features, immune microenvironment, immunotherapy prediction, and sensitivity to small molecule agents between the high- and low-risk groups were further investigated. Based on scRNA-seq, we finally identified 20 AFGs associations with the prognosis of GC patients. AFGs' high expression levels were correlated with both poor prognosis and tumor progression. Three genes ( FRZB , SPARC , and FKBP10 ) were identified as immunotherapy nonresponse-related fibroblast genes and used to construct the prognostic signature. This signature is an independent significant risk factor affecting the clinical outcomes of GC patients. Remarkably, there were more CD4 memory T cells, resting mast cells, and M2 macrophages infiltrating in the high-risk group, which was characterized by higher tumor immune exclusion. Moreover, patients with higher risk scores were more prone to not respond to immunotherapy but were more sensitive to various small molecule agents, such as memantine. In conclusion, this study constructed a fibroblast-associated ICI nonresponse gene signature, which could predict the response to immunotherapy. This study potentially revealed a novel way to overcome immune resistance in GC.

Decoding tumor-fibrosis interplay: mechanisms, impact on progression, and innovative therapeutic strategies

Malignant tumors are a category of diseases that possess invasive and metastatic capabilities, with global incidence and mortality rates remaining high. In recent years, the pivotal role of fibrosis in tumor progression, drug resistance, and immune evasion has increasingly been acknowledged. Fibrosis enhances the proliferation, migration, and invasion of tumor cells by modifying the composition and structure of the extracellular matrix, thereby offering protection for immune evasion by tumor cells. The activation of cancer-associated fibroblasts (CAFs) plays a significant role in this process, as they further exacerbate the malignant traits of tumors by secreting a variety of cytokines and growth factors. Anti-fibrotic tumor treatment strategies, including the use of anti-fibrotic drugs and inhibition of fibrosis-related signaling pathways such as Transforming Growth Factor-β (TGF-β), have demonstrated potential in delaying tumor progression and improving the effectiveness of chemotherapy, targeted therapy, and immunotherapy. In the future, by developing novel drugs that target the fibrotic microenvironment, new therapeutic options may be available for patients with various refractory tumors.

Pancreatic stellate cells and the interleukin family: Linking fibrosis and immunity to pancreatic ductal adenocarcinoma (Review)

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive form of cancer with a low survival rate. A successful treatment strategy should not be limited to targeting cancer cells alone, but should adopt a more comprehensive approach, taking into account other influential factors. These include the extracellular matrix (ECM) and immune microenvironment, both of which are integral components of the tumor microenvironment. The present review describes the roles of pancreatic stellate cells, differentiated cancer‑associated fibroblasts and the interleukin family, either independently or in combination, in the progression of precursor lesions in pancreatic intraepithelial neoplasia and PDAC. These elements contribute to ECM deposition and immunosuppression in PDAC. Therapeutic strategies that integrate interleukin and/or stromal blockade for PDAC immunomodulation and fibrogenesis have yielded inconsistent results. A deeper comprehension of the intricate interplay between fibrosis, and immune responses could pave the way for more effective treatment targets, by elucidating the mechanisms and causes of ECM fibrosis during PDAC progression.

CAR-T cell technologies that interact with the tumour microenvironment in solid tumours

INTRODUCTION

Chimeric antigen receptor (CAR) T-cells have emerged as a ground-breaking therapy for the treatment of hematological malignancies due to their capacity for rapid tumor-specific killing and long-lasting tumor immunity. However, the same success has not been observed in patients with solid tumors. Largely, this is due to the additional challenges imposed by safe and uniform target selection, inefficient CAR T-cell access to sites of disease and the presence of a hostile immunosuppressive tumor microenvironment.

AREAS COVERED

Literature was reviewed on the PubMed database from the first description of a CAR by Kuwana, Kurosawa and colleagues in December 1987 through to the present day. This literature indicates that in order to tackle solid tumors, CAR T-cells can be further engineered with additional armoring strategies that facilitate trafficking to and infiltration of malignant lesions together with reversal of suppressive immune checkpoints that operate within solid tumor lesions.

EXPERT OPINION

In this review, we describe a number of recent advances in CAR T-cell technology that set out to combat the problems imposed by solid tumors including tumor recruitment, infiltration, immunosuppression, metabolic compromise, and hypoxia.

Chimeric antigen receptor-immune cells against solid tumors: Structures, mechanisms, recent advances, and future developments

ABSTRACT

The advent of chimeric antigen receptor (CAR)-T cell immunotherapies has led to breakthroughs in the treatment of hematological malignancies. However, their success in treating solid tumors has been limited. CAR-natural killer (NK) cells have several advantages over CAR-T cells because NK cells can be made from pre-existing cell lines or allogeneic NK cells with a mismatched major histocompatibility complex (MHC), which means they are more likely to become an "off-the-shelf" product. Moreover, they can kill cancer cells via CAR-dependent/independent pathways and have limited toxicity. Macrophages are the most malleable immune cells in the body. These cells can efficiently infiltrate into tumors and are present in large numbers in tumor microenvironments (TMEs). Importantly, CAR-macrophages (CAR-Ms) have recently yielded exciting preclinical results in several solid tumors. Nevertheless, CAR-T, CAR-NK, and CAR-M all have their own advantages and limitations. In this review, we systematically discuss the current status, progress, and the major hurdles of CAR-T cells, CAR-NK cells, and CAR-M as they relate to five aspects: CAR structure, therapeutic mechanisms, the latest research progress, current challenges and solutions, and comparison according to the existing research in order to provide a reasonable option for treating solid tumors in the future.

Chimeric antigen receptor-natural killer cell therapy: current advancements and strategies to overcome challenges

Chimeric antigen receptor-natural killer (CAR-NK) cell therapy is a novel immunotherapy targeting cancer cells via the generation of chimeric antigen receptors on NK cells which recognize specific cancer antigens. CAR-NK cell therapy is gaining attention nowadays owing to the ability of CAR-NK cells to release potent cytotoxicity against cancer cells without side effects such as cytokine release syndrome (CRS), neurotoxicity and graft-versus-host disease (GvHD). CAR-NK cells do not require antigen priming, thus enabling them to be used as "off-the-shelf" therapy. Nonetheless, CAR-NK cell therapy still possesses several challenges in eliminating cancer cells which reside in hypoxic and immunosuppressive tumor microenvironment. Therefore, this review is envisioned to explore the current advancements and limitations of CAR-NK cell therapy as well as discuss strategies to overcome the challenges faced by CAR-NK cell therapy. This review also aims to dissect the current status of clinical trials on CAR-NK cells and future recommendations for improving the effectiveness and safety of CAR-NK cell therapy.

Antitumor activity of genetically engineered NK-cells in non-hematological solid tumor: a comprehensive review

Recent advancements in genetic engineering have made it possible to modify Natural Killer (NK) cells to enhance their ability to fight against various cancers, including solid tumors. This comprehensive overview discusses the current status of genetically engineered chimeric antigen receptor NK-cell therapies and their potential for treating solid tumors. We explore the inherent characteristics of NK cells and their role in immune regulation and tumor surveillance. Moreover, we examine the strategies used to genetically engineer NK cells in terms of efficacy, safety profile, and potential clinical applications. Our investigation suggests CAR-NK cells can effectively target and regress non-hematological malignancies, demonstrating enhanced antitumor efficacy. This implies excellent promise for treating tumors using genetically modified NK cells. Notably, NK cells exhibit low graft versus host disease (GvHD) potential and rarely induce significant toxicities, making them an ideal platform for CAR engineering. The adoptive transfer of allogeneic NK cells into patients further emphasizes the versatility of NK cells for various applications. We also address challenges and limitations associated with the clinical translation of genetically engineered NK-cell therapies, such as off-target effects, immune escape mechanisms, and manufacturing scalability. We provide strategies to overcome these obstacles through combination therapies and delivery optimization. Overall, we believe this review contributes to advancing NK-cell-based immunotherapy as a promising approach for cancer treatment by elucidating the underlying mechanisms, evaluating preclinical and clinical evidence, and addressing remaining challenges.

Empowering pancreatic tumor homing with augmented anti-tumor potency of CXCR2-tethered CAR-NK cells

Chimeric antigen receptor (CAR)-engineered natural killer (NK) cells are a promising immunotherapy for solid cancers; however, their effectiveness against pancreatic cancer is limited by the immunosuppressive tumor microenvironment. In particular, low NK cell infiltration poses a major obstacle that reduces cytotoxicity. The current study aimed to enhance the tumor-homing capacity of CAR-NK cells by targeting the chemokine-chemokine receptor axis between NK and pancreatic cancer cells. To this end, data from a chemokine array and The Cancer Genome Atlas pan-cancer cohort were analyzed. Pancreatic cancer cells were found to secrete high levels of ligands for C-X-C motif receptor 1 (CXCR1) and CXCR2. Subsequently, we generated anti-mesothelin CAR-NK cells incorporating CXCR1 or CXCR2 and evaluated their tumor-killing abilities in 2D cancer cell co-culture and 3D tumor-mimetic organoid models. CAR-NK cells engineered with CXCR2 demonstrated enhanced tumor killing and strong infiltration of tumor sites. Collectively, these findings highlight the potential of CXCR2-augmented CAR-NK cells as a clinically relevant modality for effective pancreatic cancer treatment. By improving their infiltration and tumor-killing capabilities, these CXCR2-augmented CAR-NK cells have the potential to overcome the challenges posed by the immunosuppressive tumor microenvironment, providing improved therapeutic outcomes.

Breaking the stromal barrier in pancreatic cancer: Advances and challenges

Pancreatic cancer (PC) remains a leading cause of mortality worldwide due to the absence of early detection methods and the low success rates of traditional therapeutic strategies. Drug resistance in PC is driven by its desmoplastic stroma, which creates a barrier that shields cancer niches and prevents the penetration of drugs. The PC stroma comprises heterogeneous cellular populations and non-cellular components involved in aberrant ECM deposition, immunosuppression, and drug resistance. These components can influence PC development through intricate and complex crosstalk with the PC cells. Understanding how stromal components and cells interact with and influence the invasiveness and refractoriness of PC cells is thus a prerequisite for developing successful stroma-modulating strategies capable of remodeling the PC stroma to alleviate drug resistance and enhance therapeutic outcomes. In this review, we explore how non-cellular and cellular stromal components, including cancer-associated fibroblasts and tumor-associated macrophages, contribute to the immunosuppressive and tumor-promoting effects of the stroma. We also examine the signaling pathways underlying their activation, tumorigenic effects, and interactions with PC cells. Finally, we discuss recent pre-clinical and clinical work aimed at developing and testing novel stroma-modulating agents to alleviate drug resistance and improve therapeutic outcomes in PC.

Microenvironmental regulation in tumor progression: Interactions between cancer-associated fibroblasts and immune cells

The tumor microenvironment (TME), the "soil" on which tumor cells grow, has an important role in regulating the proliferation and metastasis of tumor cells as well as their response to treatment. Cancer-associated fibroblasts (CAFs), as the most abundant stromal cells of the TME, can not only directly alter the immunosuppressive effect of the TME through their own metabolism, but also influence the aggregation and function of immune cells by secreting a large number of cytokines and chemokines, reducing the body's immune surveillance of tumor cells and making them more prone to immune escape. Our study provides a comprehensive review of fibroblast chemotaxis, malignant transformation, metabolic characteristics, and interactions with immune cells. In addition, the current small molecule drugs targeting CAFs have been summarized, including both natural small molecules and targeted drugs for current clinical therapeutic applications. A complete review of the role of fibroblasts in TME from an immune perspective is presented, which has important implications in improving the efficiency of immunotherapy by targeting fibroblasts.

Hydrogel-Based Therapeutics for Pancreatic Ductal Adenocarcinoma Treatment

Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest malignancies worldwide, is characteristic of the tumor microenvironments (TME) comprising numerous fibroblasts and immunosuppressive cells. Conventional therapies for PDAC are often restricted by limited drug delivery efficiency, immunosuppressive TME, and adverse effects. Thus, effective and safe therapeutics are urgently required for PDAC treatment. In recent years, hydrogels, with their excellent biocompatibility, high drug load capacity, and sustainable release profiles, have been developed as effective drug-delivery systems, offering potential therapeutic options for PDAC. This review summarizes the distinctive features of the immunosuppressive TME of PDAC and discusses the application of hydrogel-based therapies in PDAC, with a focus on how these hydrogels remodel the TME and deliver different types of cargoes in a controlled manner. Furthermore, we also discuss potential drug candidates and the challenges and prospects for hydrogel-based therapeutics for PDAC. By providing a comprehensive overview of hydrogel-based therapeutics for PDAC treatment, this review seeks to serve as a reference for researchers and clinicians involved in developing therapeutic strategies targeting the PDAC microenvironment.