Claudin18.2-Specific Chimeric Antigen Receptor Engineered T Cells for the Treatment of Gastric Cancer

Study of immunosenescence in the occurrence and immunotherapy of gastrointestinal malignancies

In human beings heterogenous, pervasive and lethal malignancies of different parts of the gastrointestinal (GI) tract viz., tumours of the oesophagus, stomach, small intestine, colon, and rectum, represent gastrointestinal malignancies. Primary treatment modality for gastric cancer includes chemotherapy, surgical interventions, radiotherapy, monoclonal antibodies and inhibitors of angiogenesis. However, there is a need to improve upon the existing treatment modality due to associated adverse events and the development of resistance towards treatment. Additionally, age has been found to contribute to increasing the incidence of tumours due to immunosenescence-associated immunosuppression. Immunosenescence is the natural process of ageing, wherein immune cells as well as organs begin to deteriorate resulting in a dysfunctional or malfunctioning immune system. Accretion of senescent cells in immunosenescence results in the creation of a persistent inflammatory environment or inflammaging, marked with elevated expression of pro-inflammatory and immunosuppressive cytokines and chemokines. Perturbation in the T-cell pools and persistent stimulation by the antigens facilitate premature senility of the immune cells, and senile immune cells exacerbate inflammaging conditions and the inefficiency of the immune system to identify the tumour antigen. Collectively, these conditions contribute positively towards tumour generation, growth and eventually proliferation. Thus, activating the immune cells to distinguish the tumour cells from normal cells and invade them seems to be a logical strategy for the treatment of cancer. Consequently, various approaches to immunotherapy, viz., programmed death ligand-1 (PD-1) inhibitors, Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors etc are being extensively evaluated for their efficiency in gastric cancer. In fact, PD-1 inhibitors have been sanctioned as late late-line therapy modality for gastric cancer. The present review will focus on deciphering the link between the immune system and gastric cancer, and the alterations in the immune system that incur during the development of gastrointestinal malignancies. Also, the mechanism of evasion by tumour cells and immune checkpoints involved along with different approaches of immunotherapy being evaluated in different clinical trials will be discussed.

The Evolving Role of Immunotherapy for Gastroesophageal Malignancies

The incorporation of immunotherapy has transformed the treatment landscape for advanced, unresectable, or metastatic gastroesophageal cancers (GECs), with improved survival outcomes. These improvements in outcomes for advanced GECs have led to clinical trials evaluating the role of immunotherapy in patients with resectable early-stage GECs. However, there remains a high burden of morbidity and mortality, and ongoing trials utilizing novel immunotherapy agents and combinations are underway. This review summarizes the findings of previous and ongoing clinical trials related to immunotherapy for patients with early- and late-stage GECs.

Development and optimization of Eva1 (MPZL2) targeting chimeric antigen receptor T cells

BACKGROUND

Whereas chimeric antigen receptor gene modified T (CAR-T) cell therapy has been clinically applied to malignant lymphomas and multiple myeloma, CAR-T cell therapy for solid tumors has so far not reached clinical application. Epithelial V-like antigen 1 (Eva1), transcribed from myelin protein zero-like 2 (MPZL2), is a small surface protein highly expressed on various tumor cells. We selected Eva1 as a novel solid tumor-target antigen because of its broad expression across various tumor types. The purpose of the present study is to develop and optimize CAR-T cells targeting Eva1.

METHOD

We prepared various humanized single chain variable fragment sequences based on a mouse anti-human Eva1 monoclonal antibody. We constructed six humanized Eva1CAR-Ts and selected one that maintained specificity and good cellular proliferation after antigen stimulation. We further optimized the length of the extracellular spacer domain and the choice of the intracellular domain in vitro and in two different xenograft mouse models.

RESULTS

We confirmed Eva1 expression on various tumor cell lines by flow cytometry and analysis of public database, but we also observed that normal monocytes weakly expressed Eva1. A combination of short spacer domain and 4-1BB or CD79A/CD40 intracellular domain provided higher treatment efficacy both in vitro and in vivo. The cytokine release on autologous monocyte stimulation to Eva1CAR-T cells was comparable to that on autologous B cell stimulation to CD19CAR-T cells. Humanized Eva1CAR-T cells demonstrated excellent therapeutic efficacy by infusing a single dose of Eva1CAR-T cells (1×106) in both NCI-H1975 lung cancer and CFPAC-1 pancreatic cancer cell line grafted model.

CONCLUSIONS

In summary, these data suggest that humanized Eva1CAR-T has promising therapeutic potential for the treatment of various Eva1-positive solid tumors. Regarding on-target/off-tumor recognition, further detailed analyses of the Eva1CAR-T cell responses to normal tissues are needed.

Claudin 18.2 Expression in 1404 Digestive Tract Adenocarcinomas Including 1175 Colorectal Carcinomas: Distinct Colorectal Carcinoma Subtypes Are Claudin 18.2 Positive

Claudin 18.2 (CLDN18.2) immunohistochemical (IHC) expression can be used to select patients with gastric/gastroesophageal junction adenocarcinomas for zolbetuximab (IMAB362) therapy, zolbetuximab (IMAB362) being a monoclonal antibody targeting CLDN18.2. The aim of this study was to correlate IHC expression of CLDN18.2 with clinicopathologic and molecular features in a large series of digestive tract cancers. IHC for CLDN18.2 was performed on tissue microarrays from 1404 adenocarcinomas including 155 gastric/gastroesophageal, 74 pancreatic ductal, and 1175 colorectal (576 in the initial test cohort; 599 in the subsequent validation cohort), and correlated with HER2 and mismatch repair (MMR) status. Cases were scored as CLDN18.2 positive or negative, with positivity defined as moderate-to-strong membranous staining in ≥75% of tumor cells. CLDN18.2 expression was correlated with clinicopathologic and molecular features for all colorectal adenocarcinomas. CLDN18.2 was positive in 39% (61/155) of gastric/gastroesophageal adenocarcinomas, 38% (28/74) of pancreatic ductal adenocarcinomas, and 3.4% (40/1175) of colorectal adenocarcinomas (P < .001). For gastric/gastroesophageal and pancreatic ductal adenocarcinoma, there was no correlation between CLDN18.2 expression and either HER2 or MMR status. In contrast, CLDN18.2-positive colorectal adenocarcinomas had distinct clinicopathologic and molecular features. CLDN18.2-positive colorectal adenocarcinomas were more frequently proximally located and were more often MMR deficient and BRAF V600E positive (all with P < .05). Quantitative pathologic analysis using the digital pathology biomarker QuantCRC (Aiforia) demonstrated marked differences in histologic features between CLDN18.2-positive and CLDN18.2-negative colorectal adenocarcinomas, with CLDN18.2-positive tumors having an increased tumor:stroma ratio and %mucin but decreased %immature stroma in both the test and validation cohorts (all with P < .05). In conclusion, CLDN18.2-positive colorectal adenocarcinomas are frequently MMR deficient and BRAF V600E mutated, and demonstrate distinct histologic features. Future studies addressing the efficacy of zolbetuximab therapy in this subset of colorectal cancers are needed.

Claudin 18 (43-14A clone) expression in pancreatic ductal adenocarcinoma: Assessment of a potential clinical biomarker for zolbetuximab therapy

Pancreatic ductal adenocarcinoma (PDAC) remains highly lethal, with a five-year survival rate below 15 %. Claudin 18.2 (CLDN18.2) has emerged as a novel potential therapeutic target in PDAC. Zolbetuximab, a monoclonal antibody targeting CLDN18.2, has demonstrated therapeutic benefit in gastric cancers and is now in phase 2 clinical trials for PDAC. Trial eligibility for zolbetuximab requires tumor membranous immunohistochemical staining with the pan-claudin 18 companion diagnostic antibody clone 43-14A. However, the expression of CLDN18 detected using this clone has only been evaluated in 62 patients from a single retrospective study. Herein, we report immunohistochemical staining using 43-14A on surgically resected PDAC samples (n = 120). Samples were stained following the protocol used in clinical trials, using the 43-14A VENTANA antibody in a prediluted kit, and according to the manufacturer's recommended protocol. Positive cases were defined as ≥ 75 % of tumor cells exhibiting membranous staining with an intensity of ≥ 2+. Out of 120 PDAC cases, 39 (32.5 %) stained positive for CLDN18 with 43-14A. A significant association was observed between lower tumor grade and higher 43-14A staining (p < 0.05). CLDN18-positive cases demonstrated significantly improved survival at the cohort's median overall survival (23 months, p < 0.05), suggesting that claudin expression could serve as a both a diagnostic and prognostic marker. Our findings indicate that 32.5 % of PDAC tumors in this cohort are positive for CLDN18, suggesting that a significant proportion of patients with PDAC could benefit from zolbetuximab and other CLDN18.2 targeted immunotherapies if pancreatic cancer therapeutic trials prove successful.

CLDN18.2-targeting STAR-T cell therapy for pancreatic cancer: a strategy to minimize gastric off-tumor toxicity compared to CLDN18.2 CAR-T

Claudin18 isoform 2 (CLDN18.2), primarily expressed in gastric tissue and upregulated in pancreatic cancer (PC), is a key target for innovative treatments like chimeric antigen receptor T (CAR-T) cell therapy. However, CAR-T's effectiveness comes with a significant risk of on-target, off-tumor (OTOT) toxicity due to CLDN18.2's presence in normal gastric mucosa. To address this, we developed CLDN18.2-specific synthetic T cell receptor and antigen receptor T (STAR-T) cells. Our research shows that STAR-T and CAR-T cells have comparable in vitro cytotoxicity, but STAR-T cells cause less gastric damage in vivo despite having weaker antitumor effects than CAR-T cells. Clinical tests with gastroscopes confirmed the gastric safety of STAR-T cell therapy, which effectively controlled the disease. Additionally, incorporating the IL12β p40 subunit into STAR-T cells enhanced their function in both lab and animal studies. This evidence suggests that CLDN18.2 STAR-T cell could be a safer alternative to CAR-T cell therapy for PC, meriting further clinical trials.

The potential of chimeric antigen receptor -T cell therapy for endocrine cancer

Endocrine cancer, a relatively rare and heterogeneous tumor with diverse clinical features. The facile synthesis of hormones further complicates endocrine cancer treatment. Thus, the development of safe and effective systemic treatment approaches, such as chimeric antigen receptor (CAR) T cell therapy, is imperative to enhance the prognosis of patients with endocrine cancer. Although this therapy has achieved good results in the treatment of hematological malignancies, it encounters diverse complications and challenges in the context of endocrine cancer. This review delineates the generation of CAR-T cells, examines the potential of CAR-T cell therapy for endocrine cancer, enumerates pivotal antigens linked to endocrine cancer, encapsulates the challenges confronted with CAR-T cell therapy for endocrine cancer, and expounds upon strategies to overcome these limitations. The primary objective is to provide insightful perspectives that can contribute to the advancement of CAR-T cell therapy in the field of endocrine cancer.

Claudin18.2 expression in gallbladder cancer correlates with immune activation and a favourable prognosis

AIMS

Gallbladder carcinoma (GBC) is frequently diagnosed and treated in advanced stages and has a poor prognosis. Recent studies have identified claudin18.2 (CLDN18.2) as a promising target in digestive system cancer. In this study, we aimed to determine the expression of CLDN18.2 and its correlation with clinicopathological characteristics in patients with GBC.

METHODS

The expression of CLDN18.2 of 228 patients with GBC was studied via immunohistochemistry. Immunostained samples were evaluated according to the H-score. The samples were divided into low/negative (H-score=0-49) and high/positive (H-score=50-300) expression groups. The correlations between CLDN18.2 and various clinicopathological characteristics, including survival, were assessed. Multiplex immunofluorescence and image acquisition were used to analyse the relationship between CLDN18.2 expression and the immune microenvironment.

RESULTS

The overall positive CLDN18.2 staining rate was 39.91% (91/228); 137 (60.08%) were given 0 points, 30 (13.15%) were given 1 point, 28 (12.28%) were given 2 points and 33 (14.47%) were given 3 points. Low CLDN18.2 expression was correlated with adverse prognostic factors, including poor differentiation, deep infiltration depth, lymph node metastasis and distant metastasis. High CLDN18.2 expression was associated with better survival. Furthermore, the distribution of immune cell subsets significantly differed between the high and low CLDN18.2 expression groups.

CONCLUSIONS

The correlations between the expression of CLDN18.2 and clinicopathological characteristics and prognosis suggest that early-stage patients could benefit more from future anti-CLDN18.2 treatment and that CLDN18.2 may function as a pivotal regulatory molecule in patients with GBC. The underlying mechanism may be related to immune activation caused by high CLDN18.2 expression.

Peptide hydrogel platform encapsulating manganese ions and high-density lipoprotein nanoparticle-mimicking nanovaccines for the prevention and treatment of gastric cancer

BACKGROUND

Advanced gastric cancer remains a significant global health challenge, with limited therapeutic options available. In contrast, immunotherapy have emerged as promising alternatives, offering greater potency in treating advanced gastric cancer. However, the development of novel and efficient immunotherapeutic strategy is crucial to enhance the body's immune response against gastric cancer.

METHODS

This study developed a single-injection peptide hydrogel-based nanovaccine therapy for gastric cancer treatment. The therapy utilizes a RADA32 peptide hydrogel, which is sensitive to metal ion concentration, to encapsulate manganese ions and HPPS nanovaccines. The HPPS nanovaccines contain antigen peptide and CpG-ODN, designed to activate both the toll-like receptor 9 (TLR9) and cGAS-STING signaling pathways in antigen-presenting cells. This design aims to facilitate a stable and sustained release of the nanovaccine, thereby enhancing the body's effective recognition and response to antigens.

RESULTS

The efficacy of the system was confirmed using the model antigen OVA and the gastric cancer-specific antigen MG7-related peptide. The results demonstrated that the nanovaccine effectively activated the immune response, leading to enhanced recognition and response to the antigens. This activation of both TLR9 and cGAS-STING pathways in antigen-presenting cells was crucial for the observed immune response, highlighting the potential of this approach to stimulate a robust and sustained immune response against gastric cancer.

CONCLUSIONS

This study presents a novel strategy for clinical anti-tumor vaccine administration, offering a promising approach for the prevention and treatment of gastric cancer. The single-injection peptide hydrogel-based nanovaccine system provides a convenient and effective method to enhance the body's immune response against gastric cancer. This approach could potentially be expanded to other types of cancer, providing a versatile platform for cancer immunotherapy.

Future Landscape of Anti-Claudin 18.2 Antibodies in Gastric Adenocarcinoma

Advanced gastric adenocarcinoma (GAC) carries a poor prognosis. Targeted therapy in GAC has traditionally been limited to anti-human epidermal growth factor receptor-2 and anti-vascular endothelial growth factor agents. Recent years have brought immune checkpoint therapy to the GAC treatment landscape. However, continued discovery of targeted therapy in GAC is needed. Claudins, transmembrane proteins located in tight junctions of epithelial and endothelial cells, help regulate cellular polarity. Claudin dysregulation has been linked to cancers and other diseases. Claudin 18.2 specifically has become a new novel and exciting biomarker for GAC. Many agents are in the investigative pipeline, including monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, and chimeric T-cell therapy. Recently, zolbetuximab, an anti-claudin 18.2 monoclonal antibody, was the first of these agents to get FDA approval. Here, we review zolbetuximab's place in therapy along with other agents being explored.

CAR-γδ T Cells Targeting Claudin18.2 Show Superior Cytotoxicity Against Solid Tumor Compared to Traditional CAR-αβ T Cells

BACKGROUND

Claudin18.2 (CLDN18.2) is highly expressed during the development of various malignant tumors, especially gastric cancer, and CAR-T cells targeting CLDN18.2 have therapeutic potential. However, their dependence on the major histocompatibility complex (MHC) for antigen recognition limits their application. Human Gamma Delta (γδ) T cells, with strong MHC-independent cytotoxicity to most solid tumors both in vivo and in vitro, are emerging as ideal cells for the generation of robust universal CLDN18.2 CAR-T cells to treat solid tumors. Our aim was to construct a universal CAR-γδ T cell targeting CLDN18.2.

METHODS

We constructed novel CAR-CLDN18.2-γδ T cells by lentiviral infection and compared their superior efficacy in the treatment of CLDN18.2-positive solid tumors in vivo and in vitro.

RESULTS

CD3ζ expression was verified in HEK293T cells after lentiviral transfection of CLDN18.2 CAR, and the lentivirus was packaged and concentrated to a titer of 4.90 × 108 TU/mL. Primary γδ T cells and αβ T cells were infected with efficiencies of approximately 31.76 ± 4.122% and 44.13 ± 4.436%, respectively. CAR-CLDN18.2-γδ T cells exhibited specific cytotoxicity against CLDN18.2-positive gastric cancer cells and secreted relatively high levels of Granzyme-B, Perforin-1, and IFN-γ. CAR-γδ T cells also showed superior cytotoxicity to target cells compared to classical CAR-αβ T cells in vitro. Finally, the antitumor activity of γδ T-CAR-CLDN18.2 cells was evaluated in tumor-bearing NSG mice, and CAR-CLDN18.2-γδ T cells significantly inhibited tumor growth and prolonged the survival of the mice.

CONCLUSIONS

Our results demonstrate that universal CAR-CLDN18.2-γδ T cell is promising for the treatment of CLDN18.2-positive solid tumor and provide insights for the development of more universal CAR-γδ T-cell strategies for tumor immunotherapy.

Hunting glioblastoma recurrence: glioma stem cells as retrospective targets

Glioblastoma (GBM) remains one of the most aggressive and treatment-resistant brain malignancies in adults. Standard approaches, including surgical resection followed by adjuvant radio- and chemotherapy with temozolomide (TMZ), provide only transient control, as GBM frequently recurs due to its infiltrative nature and the presence of therapy-resistant subpopulations such as glioma stem cells (GSCs). GSCs, with their quiescent state and robust resistance mechanisms, evade conventional therapies, contributing significantly to relapse. Consequently, current treatment methods for GBM face significant limitations in effectively targeting GSCs. In this review, we emphasize the relationship between GBM recurrence and GSCs, discuss the current limitations, and provide future perspectives to overwhelm the challenges associated with targeting GSCs. Eliminating GSCs may suppress recurrence, achieve durable responses, and improve therapeutic outcomes for patients with GBM.

Clinical significance of the tumor microenvironment on immune tolerance in gastric cancer

In the realm of oncology, the tumor microenvironment (TME)-comprising extracellular matrix components, immune cells, fibroblasts, and endothelial cells-plays a pivotal role in tumorigenesis, progression, and response to therapeutic interventions. Initially, the TME exhibits tumor-suppressive properties that can inhibit malignant transformation. However, as the tumor progresses, various factors induce immune tolerance, resulting in TME behaving in a state that promotes tumor growth and metastasis in later stages. This state of immunosuppression is crucial as it enables TME to change from a role of killing tumor cells to a role of promoting tumor progression. Gastric cancer is a common malignant tumor of the gastrointestinal tract with an alarmingly high mortality rate. While chemotherapy has historically been the cornerstone of treatment, its efficacy in prolonging survival remains limited. The emergence of immunotherapy has opened new therapeutic pathways, yet the challenge of immune tolerance driven by the gastric cancer microenvironment complicates these efforts. This review aims to elucidate the intricate role of the TME in mediating immune tolerance in gastric cancer and to spotlight innovative strategies and clinical trials designed to enhance the efficacy of immunotherapeutic approaches. By providing a comprehensive theoretical framework, this review seeks to advance the understanding and application of immunotherapy in the treatment of gastric cancer, ultimately contributing to improved patient outcomes.

Preclinical Development of T Cells Engineered to Express a T-Cell Antigen Coupler Targeting Claudin 18.2-Positive Solid Tumors

The T-cell antigen coupler (TAC) is a chimeric receptor that facilitates tumor antigen-specific activation of T cells by co-opting the endogenous T-cell receptor complex in the absence of tonic signaling. Previous data demonstrate that the TAC affords T cells with the ability to induce durable and safe antitumor responses in preclinical models of hematologic and solid tumors. In this study, we describe the preclinical pharmacology and safety of an autologous Claudin 18.2 (CLDN18.2)-directed TAC T-cell therapy, TAC01-CLDN18.2, in preparation for a phase I/II clinical study in subjects with CLDN18.2-positive solid tumors. Following a screen of putative TAC constructs, the specificity, activity, and cytotoxicity of TAC T cells expressing the final CLDN18.2-TAC receptor were evaluated in vitro and in vivo using gastric, gastroesophageal, and pancreatic tumor models as well as human cells derived from normal tissues. CLDN18.2-specific activity and cytotoxicity of CLDN18.2-TAC T cells were observed in coculture with various 2D tumor cultures naturally expressing CLDN18.2 as well as tumor spheroids. These effects occurred in models with low antigen levels and were positively associated with increasing CLDN18.2 expression. CLDN18.2-TAC T cells effectively eradicated established tumor xenografts in mice in the absence of observed off-target or on-target/off-tumor effects, elicited durable efficacy in recursive killing and tumor rechallenge experiments, and remained unreactive in coculture with human cells representing vital organs. Thus, the data demonstrate that CLDN18.2-TAC T cells can induce a specific and long-lasting antitumor response in various CLDN18.2-positive solid tumor models without notable TAC-dependent toxicities, supporting the clinical development of TAC01-CLDN18.2.

Emerging Claudin18.2-targeting Therapy for Systemic Treatment of Gastric Cancer: Seeking Nobility Amidst Danger

Gastric cancer in advanced stages lacked effective treatment options. claudin18.2 (CLDN18.2) is a membrane protein that is crucial for close junctions in the differentiated epithelial cells of the gastric mucosa, playing a vital role in barrier function, and can be hardly recognized by immune cells due to its polarity pattern. As the polarity of gastric tumor cells changes, claudin18.2 is exposed on the cell surface, resulting in immune system recognition, and making it an ideal target. In this review, we summarized the expression regulation mechanism of claudin18.2 both in normal cells and malignant tumor cells. Besides, we analyzed the available clinical results and potential areas for future research on claudin18.2-positive gastric cancer and claudin18.2-targeting therapy. In conclusion, claudin18.2 is an ideal target for gastric cancer treatment, and the claudin18.2-targeting therapy has changed the treatment pattern of gastric cancer.

CAR-T cell therapy: Advances in digestive system malignant tumors

Malignant tumors of the digestive system have had a notoriously dismal prognosis throughout history. Immunotherapy, radiotherapy, surgery, and chemotherapy are the primary therapeutic approaches for digestive system cancers. The rate of recurrence and metastasis, nevertheless, remains elevated. As one of the immunotherapies, chimeric antigen receptor T cell (CAR-T) therapy has demonstrated a promising antitumor effect in hematologic cancer. Despite undergoing numerous clinical trials, the ineffective antitumor effect and adverse effects of CAR-T cell therapy in the treatment of digestive system cancers continue to impede its clinical translation. It is necessary to surmount the restricted options for targeting proteins, the obstacles that impede CAR-T cell infiltration into solid tumors, and the limited survival time in vivo. We examined and summarized the developments, obstacles, and countermeasures associated with CAR-T therapy in digestive system cancers. Emphasis was placed on the regulatory functions of potential antigen targets, the tumor microenvironment, and immune evasion in CAR-T therapy. Thus, our analysis has furnished an all-encompassing comprehension of CAR-T cell therapy in digestive system cancers, which will generate tremendous enthusiasm for subsequent in-depth research into CAR-T-based therapies in digestive system cancers.

Emerging targets in gastric and pancreatic cancer: Focus on claudin 18.2

Recently, the molecular landscape of gastric and pancreatic cancers has advanced with Claudin 18.2 (CLDN18.2) emerging as a promising therapeutic target. Claudin 18.2, a tight junction protein, is selectively expressed in cancer cells and minimally in normal tissues, making it an attractive candidate for targeted therapy. Therapies like monoclonal antibodies (e.g., zolbetuximab), bispecific antibodies, and antibody-drug conjugates have shown significant potential in improving clinical outcomes. Early-phase clinical trials demonstrate robust antitumor activity, particularly in combination with chemotherapy and immunotherapy regimens. However, challenges such as patient selection, resistance mechanisms, and toxicity management remain critical. This review highlights the therapeutic landscape, clinical advancements, and future directions of targeting Claudin 18.2 in gastric and pancreatic cancer treatment.

Siglec-G Suppresses CD8+ T Cells Responses through Metabolic Rewiring and Can be Targeted to Enhance Tumor Immunotherapy

CD8+ T cells play a critical role in cancer immune-surveillance and pathogen elimination. However, their effector function can be severely impaired by inhibitory receptors such as programmed death-1 (PD-1) and T cell immunoglobulin domain and mucin domain-3 (Tim-3). Here Siglec-G is identified as a coinhibitory receptor that limits CD8+ T cell function. Siglec-G is highly expressed on tumor-infiltrating T cells and is enriched in the exhausted T cell subset. Ablation of Siglec-G enhances the efficacy of adoptively transferred T cells and chimeric antigen receptor (CAR) T cells in suppressing solid tumors growth. Mechanistically, sialoglycan ligands, such as CD24 on tumor cells, activate the Siglec-G-SHP2 axis in CD8+ T cells, impairing metabolic reprogramming from oxidative phosphorylation to glycolysis, which dampens cytotoxic T lymphocyte (CTL) activation, expansion, and cytotoxicity. These findings discover a critical role for Siglec-G in inhibiting CD8+ T cell responses, suggesting its potential therapeutic effect in adoptive T cell therapy and tumor immunotherapy.

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.

Novel immunotherapeutic approaches in gastric cancer

Gastric cancer is a malignant tumor that ranks third in cancer-related deaths worldwide. Early-stage gastric cancer can often be effectively managed through surgical resection. However, the majority of cases are diagnosed in advanced stages, where outcomes with conventional radiotherapy and chemotherapy remain unsatisfactory. Immunotherapy offers a novel approach to treating molecularly heterogeneous gastric cancer by modifying the immunosuppressive tumor microenvironment. Immune checkpoint inhibitors and adoptive cell therapy are regarded as promising modalities in cancer immunotherapy. Food and Drug Administration-approved programmed death-receptor inhibitors, such as pembrolizumab, in combination with chemotherapy, have significantly extended overall survival in gastric cancer patients and is recommended as a first-line treatment. Despite challenges in solid tumor applications, adoptive cell therapy has demonstrated efficacy against various targets in gastric cancer treatment. Among these approaches, chimeric antigen receptor-T cell therapy research is the most widely explored and chimeric antigen receptor-T cell therapy targeting claudin18.2 has shown acceptable safety and robust anti-tumor capabilities. However, these advancements primarily remain in preclinical stages and further investigation should be made to promote their clinical application. This review summarizes the latest research on immune checkpoint inhibitors and adoptive cell therapy and their limitations, as well as the role of nanoparticles in enhancing immunotherapy.

CAR-armored-cell therapy in solid tumor treatment

Over the past decade, chimeric antigen receptor (CAR)-T cell therapy has emerged as a revolutionary immunotherapeutic approach to combat cancer. This therapy constructs a CAR on the surface of T cells through genetic engineering techniques. The CAR is formed from a combination of antibody-derived or ligand-derived domains and T-cell receptor (TCR) domains. This enables T cells to specifically bind to and activate against tumor cells. However, the efficacy of CAR-T cells in solid tumors remains inconclusive due to several challenges such as poor tumor trafficking, infiltration, and the immunosuppressive tumor microenvironment (TME). In response, CAR natural killer (CAR-NK) and CAR macrophages (CAR-M) have been developed as complementary strategies for solid tumors. CAR-NK cells do not require HLA compatibility, demonstrate reduced toxicity, and are thus seen as potential substitutes for CAR-T cells. Furthermore, CAR-M immunotherapy is also being researched and has shown phagocytic capabilities and tumor-antigen presentation. This study discusses the features, advantages, and limitations of CAR-T, CAR-NK, and CAR-M cells in the treatment of solid tumors and suggests prospective solutions for enhancing the efficacy of CAR host-cell-based immunotherapy.

Breaking the shield of solid tumors: a combined approach for enhanced efficacy of CAR-T cells

The use of chimeric antigen receptor (CAR)-T cells has enhanced the range of available therapeutic modalities in the context of cancer treatment. CAR-T cells have demonstrated considerable efficacy in the targeted eradication of blood cancer cells, thereby stimulating substantial interest in the advancement of such therapeutic approaches. However, the efficacy of CAR-T cells against solid tumor cells has been limited due to the presence of various obstacles. Solid tumors exhibit antigenic diversity and an immunosuppressive microenvironment, which presents a challenge for immune cells attempting to penetrate the tumor. CAR-T cells also demonstrate decreased proliferative activity and cytotoxicity. Furthermore, concerns exist regarding tumor antigen loss and therapy-associated toxicity. Currently, scientists are working to enhance the structure of the CAR and improve the survival and efficiency of CAR-T cells in recognizing tumor antigens in solid tumors. Chemotherapy drugs are frequently employed in the treatment of malignant neoplasms and can also be used prior to cell therapy to enhance CAR-T cell engraftment. Recent studies have demonstrated that chemotherapy drugs can mitigate the suppressive impact of TME, eliminate the physical barrier by destroying the tumor stroma, and facilitate greater penetration of immune cells and CAR-T cells into the tumor. This, in turn, increases their survival, persistence, and cytotoxicity, as well as affects the metabolism of immune cells inside the tumor. However, the effectiveness of the combined approach against solid tumors depends on several factors, including the type of tumor, dosage, population of CAR-T cells, and individual characteristics of the body. This review examines the principal obstacles to the utilization of CAR-T cells against solid tumors, proposes solutions to these issues, and assesses the potential advantages of a combined approach to radiation exposure, which has the potential to enhance the sensitivity of the tumor to other agents.

Role of tight junction proteins in shaping the immune milieu of malignancies

INTRODUCTION

Tight junctions (TJs) and their constituent proteins play pivotal roles in cellular physiology and anatomy by establishing functional boundaries within and between neighboring cells. While the involvement of TJ proteins, such as claudins, in cancer is extensively studied, studies highlighting their interaction with immune system are still meager. Studies indicate that alterations in cytokines and immune cell populations can affect TJ proteins, compromising TJ barrier function and exacerbating pro-inflammatory conditions, potentially leading to epithelial cell malignancy. Disrupted TJs in established tumors may foster a pro-tumor immune microenvironment, facilitating tumor progression, invasion, epithelial-to-mesenchymal transition and metastasis. Although previous literature contains many studies describing the involvement of TJs in pathogenesis of malignancies their role in modulating the immune microenvironment of tumors is just beginning to be unleashed.

AREAS COVERED

This article for the first time attempts to discern the importance of interaction between TJs and immune microenvironment in malignancies. To achieve the above aim a thorough search of databases like PubMed and Google Scholar was conducted to identify the recent and relevant articles on the topic.

EXPERT OPINION

Breaking the vicious cycle of dysbiosis/infections/chemical/carcinogen-induced inflammation-TJ remodeling-malignancy-TJ dysregulation-more inflammation can be used as a strategy to complement the effect of immunotherapies in various malignancies.

Pan-cancer analysis of CLDN18.2 shed new insights on the targeted therapy of upper gastrointestinal tract cancers

Background

CLDN18.2 is a widely researched drug target. However, previous research has primarily been based on immunohistochemistry results and focused on gastric cancer.

Methods

To analyze the potential cancer-targeting effect of CLDN18.2 from a multi-omics perspective, this study quantified CLDN18.2 expression in The Cancer Genome Atlas (TCGA) pan-cancer cohort. Thus, the relationships between CLDN18.2 expression and genomic alterations, immune infiltration, and prognosis were analyzed. Additionally, we performed analyses of the differentially expressed genes and enriched pathways between the high- and low-CLDN18.2 expression groups, as well as the corresponding drug sensitivity analyses.

Results

The results indicated that CLDN18.2 was highly expressed in pancreatic adenocarcinoma (PAAD), stomach adenocarcinoma (STAD), colorectal cancer (CRC), and esophageal carcinoma (ESCA). Moreover, the high- and low-CLDN18.2 expression groups presented significant differences in terms of genomic alterations and immune infiltration, such as the levels of methylation and CD4+ T cell infiltration. Furthermore, high CLDN18.2 expression was significantly associated with poor prognosis in bladder urothelial carcinoma (BLCA), ESCA, and PAAD. In upper gastrointestinal tract cancers (STAD, ESCA, and PAAD), downregulated gene-enriched pathways were associated with cell signaling, whereas upregulated gene-enriched pathways were associated with angiogenesis. Finally, we identified drugs associated with CLDN18.2 expression to which samples with different levels of expression were differentially sensitive.

Conclusion

CLDN18.2 was highly expressed in upper gastrointestinal tract cancers, and its expression had a significant effect on genomic alterations and the tumor microenvironment. Additionally, low CLDN18.2 expression was linked to favorable prognosis. Our study reveals the potential value of CLDN18.2 for tumor prognosis and targeted therapy in various cancers, especially upper gastrointestinal tract cancers.

Dual targeting chimeric antigen receptor cells enhance antitumour activity by overcoming T cell exhaustion in pancreatic cancer

BACKGROUND AND PURPOSE

Although our previous data indicated that claudin 18 isoform 2 (CLDN18.2)-targeted chimeric antigen receptor (CAR) T cells displayed remarkable clinical efficacy in CLDN18.2-positive gastric cancer, their efficacy is limited in pancreatic ductal adenocarcinoma (PDAC). The tumour microenvironment (TME) is one of the main obstacles to the efficacy of CAR-T and remodelling the TME may be a possible way to overcome this obstacle. The TME of PDAC is characterized by abundant cancer-related fibroblasts (CAFs), which hinder the infiltration and function of CLDN18.2-targeted CAR-T cells. The expression of fibroblast activation protein alpha (FAP) is an important feature of active CAFs, providing potential targets for eliminating CAFs.

EXPERIMENTAL APPROACH

In this study, we generated 10 FAP/CLDN 18.2 dual-targeted CAR-T cells and evaluated their anti-tumour ability in vitro and in vivo.

KEY RESULTS

Compared with conventional CAR-T cells, some dual-targeted CAR-T cells showed improved therapeutic effects in mouse pancreatic cancers. Further, dual-targeted CAR-T cells with better anti-tumour effect could suppress the recruitment of myeloid-derived suppressor cells (MDSCs) to improve the immunosuppressive TME, which contributes to the survival of CD8+ T cells. Moreover, dual-targeted CAR-T cells reduced the exhaustion of T cells in transforming TGF-β dependent manner.

CONCLUSION AND IMPLICATIONS

The dual-targeted CAR-T cells obtained enhancement of T effector function, inhibition of T cell exhaustion, and improvement of tumour microenvironment. Our findings provide a theoretical rationale for dual-targeted FAP/CLDN 18.2 CAR-T cells therapy in PDAC.

Diffuse Gastric Cancer: A Comprehensive Review of Molecular Features and Emerging Therapeutics

Diffuse-type gastric cancer (DGC) accounts for approximately one-third of gastric cancer diagnoses but is a more clinically aggressive disease with peritoneal metastases and inferior survival compared with intestinal-type gastric cancer (IGC). The understanding of the pathogenesis of DGC has been relatively limited until recently. Multiomic studies, particularly by The Cancer Genome Atlas, have better characterized gastric adenocarcinoma into molecular subtypes. DGC has unique molecular features, including alterations in CDH1, RHOA, and CLDN18-ARHGAP26 fusions. Preclinical models of DGC characterized by these molecular alterations have generated insight into mechanisms of pathogenesis and signaling pathway abnormalities. The currently approved therapies for treatment of gastric cancer generally provide less clinical benefit in patients with DGC. Based on recent phase II/III clinical trials, there is excitement surrounding Claudin 18.2-based and FGFR2b-directed therapies, which capitalize on unique biomarkers that are enriched in the DGC populations. There are numerous therapies targeting Claudin 18.2 and FGFR2b in various stages of preclinical and clinical development. Additionally, there have been preclinical advancements in exploiting unique therapeutic vulnerabilities in several models of DGC through targeting of the focal adhesion kinase (FAK) and Hippo pathways. These preclinical and clinical advancements represent a promising future for the treatment of DGC.

CAR-NK cells for gastrointestinal cancer immunotherapy: from bench to bedside

BACKGROUND

Gastrointestinal (GI) cancers represent a significant health burden worldwide. Their incidence continues to increase, and their management remains a clinical challenge. Chimeric antigen receptor (CAR) natural killer (NK) cells have emerged as a promising alternative to CAR-T cells for immunotherapy of GI cancers. Notably, CAR-NK cells offer several advantages, including reduced risk of graft-versus-host disease, lower cytokine release syndrome, and the ability to target cancer cells through both CAR-dependent and natural cytotoxic mechanisms.

MAIN BODY

This review comprehensively discusses the development and applications of CAR-NK cells in the treatment of GI cancers. We explored various sources of NK cells, CAR design strategies, and the current state of CAR-NK cell therapy for GI cancers, highlighting recent preclinical and clinical trials. Additionally, we addressed existing challenges and propose potential strategies to enhance the efficacy and safety of CAR-NK cell therapy.

CONCLUSIONS

Our findings highlight the potential of CAR-NK cells to revolutionize GI cancer treatment and pave the way for future clinical applications.

Expression profiles of cadherin 17 and claudin 18.2 in comparison with peptide hormonal expression in pancreatic neuroendocrine tumours: Implications for targeted immunotherapy

Cadherin 17 (CDH17) and claudin 18.2 (CLDN18.2) are highly selective markers of intestinal and gastric lineages and are expressed in adenocarcinomas of various organs. They have also been identified as potential targets for immunotherapy. Expression of CDH17 and CLDN18.2 has been observed in a subset of pancreatic neuroendocrine tumours (PanNETs). This study investigates the immunohistochemical expression of CDH17 and CLDN18 in PanNETs in comparison with hormonal expression profiles to provide baseline data for determining candidate indications for targeted therapy with CDH17 and CLDN18.2 in PanNETs, including insulinomas (n = 22), glucagonomas (n = 13), gastrinomas (n = 3), serotoninomas (n = 2) and PanNETs not otherwise specified (NOS) (n = 17). In the normal pancreas, CDH17 was expressed in the lateral membrane of ducts and some islet cells, whereas CLDN18 was occasionally expressed in the intercalated ducts and centroacinar cells. In PanNETs, CDH17 and CLDN18 was detected by membranous staining. CDH17 expression was observed in 10 to 17 (58.8 %) PanNETs NOS, 3 of 13 (23.1 %) glucagonomas, 1 of 3 (33.3 %,) gastrinomas, 1 of 2 (50 %) serotoninomas, and none of the insulinomas. According to predefined criteria, 7 of 17 (41.2 %) PanNETs NOS, 1 of 3 (33.3 %) gastrinomas, and 1 of 2 (50 %) serotoninomas were classified as CDH17-positive. There were no significant differences in clinicopathological features between CDH17-positive and CDH17-negative PanNETs, except for a higher tumour grade in the former (p<0.05). For CLDN18, expression was noted in 2 out of 3 (66.7 %) gastrinomas, one with focal staining and the other with diffuse staining. One of three (33.3 %) gastrinomas was classified as CLDN18-positive using predefined criteria. These findings suggest that a particular subset of PanNETs, including PanNET NOS, gastrinoma, and serotoninoma, may be potential candidates for CDH17-targeted immunotherapy. Additionally, gastrinoma may be a potential candidate for immunotherapy targeting CLDN18.2.

CMG901, a Claudin18.2-specific antibody-drug conjugate, for the treatment of solid tumors

Claudin18.2 has been recently recognized as a potential therapeutic target for gastric/gastroesophageal junction or pancreatic cancer. Here, we develop a Claudin18.2-directed antibody-drug conjugate (ADC), CMG901, with a potent microtubule-targeting agent MMAE (monomethyl auristatin E) and evaluate its preclinical profiles. In vitro studies show that CMG901 binds specifically to Claudin18.2 on the cell surface and kills tumor cells through direct cytotoxicity, antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and bystander killing activity. In vivo pharmacological studies show significant antitumor activity in patient-derived xenograft (PDX) models. Toxicity studies show that the major adverse effects related to CMG901 are reversible hematopoietic changes attributed to MMAE. The highest non-severely toxic dose (HNSTD) is 6 mg/kg in cynomolgus monkeys and 10 mg/kg in rats once every 3 weeks. CMG901's favorable preclinical profile supports its entry into the human clinical study. CMG901 is currently under phase 3 investigation in patients with advanced gastric/gastroesophageal junction adenocarcinoma expressing Claudin18.2 (NCT06346392).

Exploring the potential of the convergence between extracellular vesicles and CAR technology as a novel immunotherapy approach

Cancer therapy is a dynamically evolving field, witnessing the emergence of innovative approaches that offer a promising outlook for patients grappling with persistent disease. Within the realm of therapeutic exploration, chimeric antigen receptor (CAR) T cells as well as CAR NK cells, have surfaced as novel approaches, each possessing unique attributes and transformative potential. Immune cells engineered to express CARs recognizing tumour-specific antigens, have shown remarkable promise in treating terminal cancers by combining the precision of antibody specificity with the potent cytotoxic function of T cells. However, their application in solid tumours is still in its nascent stages, presenting unique major challenges. On the same note, CAR NK cells offer a distinct immunotherapeutic approach, utilizing CARs on NK cells, providing advantages in safety, manufacturing simplicity, and a broader scope for cancer treatment. Extracellular vesicles (EVs) have emerged as promising therapeutic agents due to their ability to carry crucial biomarkers and biologically active molecules, serving as vital messengers in the intercellular communication network. In the context of cancer, the therapeutic potential of EVs lies in delivering tumour-suppressing proteins, nucleic acid components, or targeting drugs with precision, thereby redefining the paradigm of precision medicine. The fusion of CAR technology with the capabilities of EVs has given rise to a new therapeutic frontier. CAR T EVs and CAR NK EVs, leveraging the power of EVs, have the potential to alleviate challenges associated with live-cell therapies. EVs are suggested to reduce the side effects linked to CAR T cell therapy and hold the potential to revolutionize the penetrance in solid tumours. EVs act as carriers of pro-apoptotic molecules and RNA components, enhancing immune responses and thereby expanding their therapeutic potential. In this review article, we navigate dynamic landscapes, with our objective being to evaluate comparative efficacy, safety profiles, manufacturing complexities, and clinical applicability.

Targeting endothelial cell anergy to improve CAR T cell therapy for solid tumors

Chimeric antigen receptor (CAR) T cell therapy presents significant results, especially for the treatment of hematologic malignancies. However, there are limitations and challenges to be overcome to achieve similar success for the treatment of solid tumors. These challenges involve selection of the target, infiltration into the tumor microenvironment and maintenance of functionality. The tumor vasculature is a major barrier for leukocytes to enter the tumor parenchyma. Due to the exposure of the vasculature to angiogenic growth factors during tumor progression, the endothelial cells become anergic to inflammatory cytokines, resulting in reduced leukocyte adhesion molecule expression. As such adhesion molecules are a prerequisite for leukocyte extravasation, endothelial cell anergy allows tumors to escape from endogenous immunity, as well as from cellular immunotherapies such as CAR T cells. Hence, overcoming endothelial cell anergy, e.g. through the administration of angiogenesis inhibitors, is believed to restore anti-tumor immunity. Concomitantly, both endogenous immune cells as well as cellular therapeutics such as CAR T cells can permeate into the tumor parenchyma. Here, we discuss how prior or concomitant treatment with an antiangiogenic drug can improve CAR T cell therapy, to become an attractive strategy for the treatment of solid tumors.

Clinical significance of peripheral blood immune cells in patients with gastric cancer after surgery

BACKGROUND

Gastric cancer is one of the most common malignant tumors worldwide, and surgical resection is one of the main ways to treat gastric cancer. However, the immune status of postoperative patients is crucial for prognosis and survival, and immune cells play an important role in this process. Therefore, it is helpful to understand the immune status of postoperative patients by evaluating the levels of peripheral blood immune cells, especially total T cells (CD3+), helper T cells (CD3+CD4+), and suppressor T cells (CD3+CD8+), and its relationship to survival.

AIM

To analyzed the immune cells in peripheral blood of patients with gastric cancer after surgery, detect the levels of total T cells, helper T cells and suppressor T cells.

METHODS

A total of 58 patients with gastric cancer who received surgical treatment were included in the retrospective study. Flow cytometry was used to detect the level of peripheral blood immune cells and analyze the correlation between total T cells, helper T cells and inhibitory T cells. To explore the relationship between these immune markers and patient survival.

RESULTS

The results showed that the levels of total T cells, helper T cells, and suppressor T cells changed in patients after gastric cancer surgery. There was a significant positive correlation between total T cells, helper T cells and suppressor T cells (r = 0.35, P < 0.01; r = 0.56, P < 0.01). However, there was a negative correlation between helper T cells and suppressor T cells (r = -0.63, P < 0.01). Follow-up showed that the survival rate of patients in the high-level total T cell group was significantly higher than that in the low-level group (28.87 ± 24.98 months vs 18.42 ± 16.21 months). The survival curve shows that the curve of patients in the high-level group is shifted to the upper right, and that of the low-level group is shifted downward. There was no significant difference between the levels of helper T cells and suppressor T cells and patient survival time.

CONCLUSION

By detecting peripheral blood immune cells with flow cytometry, we can initially evaluate the immune status of patients after gastric cancer surgery and initially explore its relationship with patient survival.

3D bioprinted tumor model: a prompt and convenient platform for overcoming immunotherapy resistance by recapitulating the tumor microenvironment

BACKGROUND

Cancer immunotherapy is receiving worldwide attention for its induction of an anti-tumor response. However, it has had limited efficacy in some patients who acquired resistance. The dynamic and sophisticated complexity of the tumor microenvironment (TME) is the leading contributor to this clinical dilemma. Through recapitulating the physiological features of the TME, 3D bioprinting is a promising research tool for cancer immunotherapy, which preserves in vivo malignant aggressiveness, heterogeneity, and the cell-cell/matrix interactions. It has been reported that application of 3D bioprinting holds potential to address the challenges of immunotherapy resistance and facilitate personalized medication.

CONCLUSIONS AND PERSPECTIVES

In this review, we briefly summarize the contributions of cellular and noncellular components of the TME in the development of immunotherapy resistance, and introduce recent advances in 3D bioprinted tumor models that served as platforms to study the interactions between tumor cells and the TME. By constructing multicellular 3D bioprinted tumor models, cellular and noncellular crosstalk is reproduced between tumor cells, immune cells, fibroblasts, adipocytes, and the extracellular matrix (ECM) within the TME. In the future, by quickly preparing 3D bioprinted tumor models with patient-derived components, information on tumor immunotherapy resistance can be obtained timely for clinical reference. The combined application with tumoroid or other 3D culture technologies will also help to better simulate the complexity and dynamics of tumor microenvironment in vitro. We aim to provide new perspectives for overcoming cancer immunotherapy resistance and inspire multidisciplinary research to improve the clinical application of 3D bioprinting technology.

Claudin18.2-specific CAR T cells in gastrointestinal cancers: phase 1 trial final results

Claudin18.2 (CLDN18.2) is highly expressed with the development of various malignant tumors, especially gastrointestinal cancers, and is emerging as a new target for cancer treatment. Satricabtagene autoleucel (satri-cel)/CT041 is an autologous chimeric antigen receptor (CAR) T cell targeting CLDN18.2, and the interim results of the CT041-CG4006 trial were reported in June 2022. Here we present the final results of this single-arm, open-label, phase 1 trial, which evaluated the safety and efficacy of satri-cel in patients with CLDN18.2-positive advanced gastrointestinal cancers. This trial included a dose-escalation stage (n = 15) and a dose-expansion stage in four different cohorts (total n = 83): cohort 1, satri-cel monotherapy in 61 patients with standard chemotherapy-refractory gastrointestinal cancers; cohort 2, satri-cel plus anti-PD-1 therapy in 15 patients with standard chemotherapy-refractory gastrointestinal cancers; cohort 3, satri-cel as sequential treatment after first-line therapy in five patients with gastrointestinal cancers; and cohort 4, satri-cel monotherapy in two patients with anti-CLDN18.2 monoclonal antibody-refractory gastric cancer. The primary endpoint was safety; secondary endpoints included efficacy, pharmacokinetics and immunogenicity. A total of 98 patients received satri-cel infusion, among whom 89 were dosed with 2.5 × 108, six with 3.75 × 108 and three with 5.0 × 108 CAR T cells. Median follow-up was 32.4 months (95% confidence interval (CI): 27.3, 36.5) since apheresis. No dose-limiting toxicities, treatment-related deaths or immune effector cell-associated neurotoxicity syndrome were reported. Cytokine release syndrome occurred in 96.9% of patients, all classified as grade 1-2. Gastric mucosal injuries were identified in eight (8.2%) patients. The overall response rate and disease control rate in all 98 patients were 38.8% and 91.8%, respectively, and the median progression-free survival and overall survival were 4.4 months (95% CI: 3.7, 6.6) and 8.8 months (95% CI: 7.1, 10.2), respectively. Satri-cel demonstrates therapeutic potential with a manageable safety profile in patients with CLDN18.2-positive advanced gastrointestinal cancer. ClinicalTrials.gov identifier: NCT03874897 .

Development and validation of ELISA method for quantification of Q-1802 in serum and its application to pharmacokinetic study in ICR Mouse

Q-1802 is a humanized bispecific antibody targeting programmed death-ligand 1 (PD-L1) and Claudin 18.2 (CLDN18.2). It can bind to CLDN18.2 and mediate antibody-dependent cell-mediated cytotoxicity against tumor cells. The Fc segment of the antibody recognizing PD-L1 blocks PD-1 signaling and activates innate immunity and adaptive immunity. In this study, we report the development, validation, and application of sensitive and high-throughput enzyme-linked immunosorbent assays (ELISA) to measure the concentrations of Q-1802 in ICR mouse serum. The assay is sensitive, with a lower limit of quantification of 50 ng/mL, has a broad dynamic range of 50-3200 ng/mL, and exhibits excellent precision and accuracy. These assays were successfully applied to in vitro serum stability and pharmacokinetic (PK) studies. In conclusion, we have developed and validated a highly sensitive and selective method for measuring Q-1802 in ICR mouse serum. The development and validation steps of assays met the required criteria for validation, which suggested that these can be applied to quantify Q-1802, as well as in PK studies.

Emerging Therapeutic Targets and Future Directions in Advanced Gastric Cancer: A Comprehensive Review

Metastatic gastric cancer (GC) still represents a critical clinical challenge, with limited treatment options and a poor prognosis. Most patients are diagnosed at advanced stages, limiting the chances of surgery and cure. The identification of molecular targets and the possibility of combining immune checkpoint inhibitors with chemotherapy have recently reshaped the therapeutic landscape of metastatic gastric cancer. The new classification of gastric cancer, mainly based on immunologic and molecular criteria such as programmed cell death 1 (PD-1), microsatellite instability (MSI), and human epidermal growth factor receptor 2 (HER2), has made it possible to identify and differentiate patients who may benefit from immunotherapy, targeted therapy, or chemotherapy alone. All relevant and available molecular and immunological targets in clinical practice for the systemic treatment of this disease are presented. Particular attention is given to possible future approaches, including circulating tumor DNA (ctDNA) for therapeutic monitoring, new targeting agents against molecular pathways such as fibroblast growth factor receptor (FGFR) and MET, chimeric antigen receptor (CAR)-T cells, and cancer vaccines. This review aims to provide a comprehensive understanding of current targets in advanced gastric cancer and to offer valuable insights into future directions of research and clinical practice in this challenging disease.

Gastric cancer immunosuppressive microenvironment heterogeneity: implications for therapy development

Although immunotherapy has revolutionized solid tumor treatment, durable responses in gastric cancer (GC) remain limited. The heterogeneous tumor microenvironment (TME) facilitates immune evasion, contributing to resistance to conventional and immune therapies. Recent studies have highlighted how specific TME components in GC acquire immune escape capabilities through cancer-specific factors. Understanding the underlying molecular mechanisms and targeting the immunosuppressive TME will enhance immunotherapy efficacy and patient outcomes. This review summarizes recent advances in GC TME research and explores the role of the immune-suppressive system as a context-specific determinant. We also provide insights into potential treatments beyond checkpoint inhibition.

Progress of Clinical Studies Targeting Claudin18.2 for the Treatment of Gastric Cancer

Claudin18.2 is a tight junction protein, highly selective, generally expressed only in normal gastric mucosal epithelial cells, which can effectively maintain the polarity of epithelial and endothelial cells, thus effectively regulating the permeability and conductance of the paracellular pathway. Abnormal expression of Claudin18.2 can occur in various primary malignant tumors, especially gastrointestinal tumors, and even in metastatic foci. It regulates its expression by activating the aPKC/MAPK/AP-1 pathway, and therefore, the Claudin18.2 protein is a pan-cancer target expressed in primary and metastatic lesions in human cancer types. Zolbetuximab (IMAB362), an antibody specific for Claudin18.2, has been successfully tested in a phase III clinical trial, and the results of the study showed that combining Zolbetuximab with chemotherapy notably extends patients' survival and is expected to be a potential first-line treatment for patients with Claudin18.2(+)/HER-2(-) gastric cancer. Here, we systematically describe the biological properties and oncogenic effects of Claudin18.2, centering on its clinical-pathological aspects and the progress of drug studies in gastric cancer, which can help to further explore its clinical value.

Genetically Engineered CLDN18.2 CAR-T Cells Expressing Synthetic PD1/CD28 Fusion Receptors Produced Using a Lentiviral Vector

This study aimed to develop synthetic Claudin18.2 (CLDN18.2) chimeric antigen receptor (CAR)-T (CAR-T) cells as a treatment for advanced gastric cancer using lentiviral vector genetic engineering technology that targets the CLDN18.2 antigen and simultaneously overcomes the immunosuppressive environment caused by programmed cell death protein 1 (PD-1). Synthetic CAR T cells are a promising approach in cancer immunotherapy but face many challenges in solid tumors. One of the major problems is immunosuppression caused by PD-1. CLDN18.2, a gastric-specific membrane protein, is considered a potential therapeutic target for gastric and other cancers. In our study, CLDN18.2 CAR was a second-generation CAR with inducible T-cell costimulatory (CD278), and CLDN18.2-PD1/CD28 CAR was a third-generation CAR, wherein the synthetic PD1/CD28 chimeric-switch receptor (CSR) was added to the second-generation CAR. In vitro, we detected the secretion levels of different cytokines and the killing ability of CAR-T cells. We found that the secretion of cytokines such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) secreted by three types of CAR-T cells was increased, and the killing ability against CLDN18.2-positive GC cells was enhanced. In vivo, we established a xenograft GC model and observed the antitumor effects and off-target toxicity of CAR-T cells. These results support that synthetic anti-CLDN18.2 CAR-T cells have antitumor effect and anti-CLDN18.2-PD1/CD28 CAR could provide a promising design strategy to improve the efficacy of CAR-T cells in advanced gastric cancer.

Emerging Targets and Therapeutics in Immuno-Oncology: Insights from Landscape Analysis

In the ever-evolving landscape of cancer research, immuno-oncology stands as a beacon of hope, offering novel avenues for treatment. This study capitalizes on the vast repository of immuno-oncology-related scientific documents within the CAS Content Collection, totaling over 350,000, encompassing journals and patents. Through a pioneering approach melding natural language processing with the CAS indexing system, we unveil over 300 emerging concepts, depicted in a comprehensive "Trend Landscape Map". These concepts, spanning therapeutic targets, biomarkers, and types of cancers among others, are hierarchically organized into eight major categories. Delving deeper, our analysis furnishes detailed quantitative metrics showcasing growth trends over the past three years. Our findings not only provide valuable insights for guiding future research endeavors but also underscore the merit of tapping the vast and unparalleled breadth of existing scientific information to derive profound insights.

Current and future immunotherapeutic approaches in pancreatic cancer treatment

Pancreatic cancer is a major cause of cancer-related death, but despondently, the outlook and prognosis for this resistant type of tumor have remained grim for a long time. Currently, it is extremely challenging to prevent or detect it early enough for effective treatment because patients rarely exhibit symptoms and there are no reliable indicators for detection. Most patients have advanced or spreading cancer that is difficult to treat, and treatments like chemotherapy and radiotherapy can only slightly prolong their life by a few months. Immunotherapy has revolutionized the treatment of pancreatic cancer, yet its effectiveness is limited by the tumor's immunosuppressive and hard-to-reach microenvironment. First, this article explains the immunosuppressive microenvironment of pancreatic cancer and highlights a wide range of immunotherapy options, including therapies involving oncolytic viruses, modified T cells (T-cell receptor [TCR]-engineered and chimeric antigen receptor [CAR] T-cell therapy), CAR natural killer cell therapy, cytokine-induced killer cells, immune checkpoint inhibitors, immunomodulators, cancer vaccines, and strategies targeting myeloid cells in the context of contemporary knowledge and future trends. Lastly, it discusses the main challenges ahead of pancreatic cancer immunotherapy.

CXCL10 and IL15 co-expressing chimeric antigen receptor T cells enhance anti-tumor effects in gastric cancer by increasing cytotoxic effector cell accumulation and survival

Chimeric antigen receptor (CAR) T cells have demonstrated outstanding therapeutic success in hematological malignancies. Yet, their efficacy against solid tumors remains constrained due to inadequate infiltration of cytotoxic T and CAR-T cells in the tumor microenvironment (TME), a factor correlated with poor prognosis in patients with solid tumors. To overcome this limitation, we engineered CAR-T cells to secrete CXCL10 and IL15 (10 × 15 CAR-T), which sustain T cell viability and enhance their recruitment, thereby amplifying the long-term cytotoxic capacity of CAR-T cells in vitro. In a xenograft model employing NUGC4-T21 cells, mice receiving 10 × 15 CAR-T cells showed superior tumor reduction and extended survival rates compared to those treated with second-generation CAR-T cells. Histopathological evaluations indicated a pronounced increase in cytotoxic T cell accumulation in the TME post 10 × 15 CAR-T cell treatment. Therefore, the synergistic secretion of CXCL10 and IL15 in these CAR-T cells enhances T cell recruitment and adaptability within tumor tissues, improving tumor control. This approach may offer a promising strategy for advancing CAR-T therapies in the treatment of solid tumors.

Claudin 18.2 as a novel therapeutic target

Claudin 18.2, a tight-junction molecule predominantly found in the nonmalignant gastric epithelium, becomes accessible on the tumour cell surface during malignant transformation, thereby providing an appealing target for cancer therapy. Data from two phase III trials testing the anti-claudin 18.2 antibody zolbetuximab have established claudin 18.2-positive advanced-stage gastric cancers as an independent therapeutic subset that derives benefit from the addition of this agent to chemotherapy. This development has substantially increased the percentage of patients eligible for targeted therapy. Furthermore, newer treatments, such as high-affinity monoclonal antibodies, bispecific antibodies, chimeric antigen receptor T cells and antibody-drug conjugates capable of bystander killing effects, have shown considerable promise in patients with claudin 18.2-expressing gastric cancers. This new development has resulted from drug developers moving beyond traditional targets, such as driver gene alterations or growth factors. In this Review, we highlight the biological rationale and explore the clinical activity of therapies that target claudin 18.2 in patients with advanced-stage gastric cancer and explore the potential for expansion of claudin 18.2-targeted therapies to patients with other claudin 18.2-positive solid tumours.

CD8+ T cell-based cancer immunotherapy

The immune system in humans is a defense department against both exogenous and endogenous hazards, where CD8+ T cells play a crucial role in opposing pathological threats. Various immunotherapies based on CD8+ T cells have emerged in recent decades, showing their promising results in treating intractable diseases. However, in the fight against the constantly changing and evolving cancers, the formation and function of CD8+ T cells can be challenged by tumors that might train a group of accomplices to resist the T cell killing. As cancer therapy stepped into the era of immunotherapy, understanding the physiological role of CD8+ T cells, studying the machinery of tumor immune escape, and thereby formulating different therapeutic strategies become the imperative missions for clinical and translational researchers to fulfill. After brief basics of CD8+ T cell-based biology is covered, this review delineates the mechanisms of tumor immune escape and discusses different cancer immunotherapy regimens with their own advantages and setbacks, embracing challenges and perspectives in near future.

Claudins in Cancer: A Current and Future Therapeutic Target

Claudins are a family of 27 proteins that have an important role in the formation of tight junctions. They also have an important function in ion exchange, cell mobility, and the epithelial-to-mesenchymal transition, the latter being very important in cancer invasion and metastasis. Therapeutic targeting of claudins has been investigated to improve cancer outcomes. Recent evidence shows improved outcomes when combining monoclonal antibodies against claudin 18.2 with chemotherapy for patients with gastroesophageal junction cancer. Currently, chimeric antigen receptor T-cells targeting claudin 18 are under investigation. In this review, we will discuss the major functions of claudins, their distribution in the normal as well as cancerous tissues, and their effect in cancer metastasis, with a special focus on the therapeutic targeting of claudins to improve cancer outcomes.

Current challenges and therapeutic advances of CAR-T cell therapy for solid tumors

The application of chimeric antigen receptor (CAR) T cells in the management of hematological malignancies has emerged as a noteworthy therapeutic breakthrough. Nevertheless, the utilization and effectiveness of CAR-T cell therapy in solid tumors are still limited primarily because of the absence of tumor-specific target antigen, the existence of immunosuppressive tumor microenvironment, restricted T cell invasion and proliferation, and the occurrence of severe toxicity. This review explored the history of CAR-T and its latest advancements in the management of solid tumors. According to recent studies, optimizing the design of CAR-T cells, implementing logic-gated CAR-T cells and refining the delivery methods of therapeutic agents can all enhance the efficacy of CAR-T cell therapy. Furthermore, combination therapy shows promise as a way to improve the effectiveness of CAR-T cell therapy. At present, numerous clinical trials involving CAR-T cells for solid tumors are actively in progress. In conclusion, CAR-T cell therapy has both potential and challenges when it comes to treating solid tumors. As CAR-T cell therapy continues to evolve, further innovations will be devised to surmount the challenges associated with this treatment modality, ultimately leading to enhanced therapeutic response for patients suffered solid tumors.

Tumor and Peritoneum-Associated Macrophage Gene Signature as a Novel Molecular Biomarker in Gastric Cancer

A spectrum of immune states resulting from tumor resident macrophages and T-lymphocytes in the solid tumor microenvironment correlates with patient outcomes. We hypothesized that in gastric cancer (GC), macrophages in a polarized immunosuppressive transcriptional state would be prognostic of poor survival. We derived transcriptomic signatures for M2 (M2TS, MRC1; MS4A4A; CD36; CCL13; CCL18; CCL23; SLC38A6; FGL2; FN1; MAF) and M1 (M1TS, CCR7; IL2RA; CXCL11; CCL19; CXCL10; PLA1A; PTX3) macrophages, and cytolytic T-lymphocytes (CTLTS, GZMA; GZMB; GZMH; GZMM; PRF1). Primary GC in a TCGA stomach cancer dataset was evaluated for signature expressions, and a log-rank test determined overall survival (OS) and the disease-free interval (DFI). In 341 TCGA GC entries, high M2TS expression was associated with histological types and later stages. Low M2TS expression was associated with significantly better 5-year OS and DFI. We validated M2TS in prospectively collected peritoneal fluid of a GC patient cohort (n = 28). Single-cell RNA sequencing was used for signature expression in CD68+CD163+ cells and the log-rank test compared OS. GC patients with high M2TS in CD68+CD163+ cells in their peritoneal fluid had significantly worse OS than those with low expression. Multivariate analyses confirmed M2TS was significantly and independently associated with survival. As an independent predictor of poor survival, M2TS may be prognostic in primary tumors and peritoneal fluid of GC patients.

The use of T-cells with chimeric antigen receptor (CAR-T) in combination with chemotherapy and radiotherapy for the treatment of solid tumors

The introduction of chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematological diseases, particularly in combating blood cancer. The success of this cell therapy approach has led to the development of approximately seven commercial CAR-T based drugs. However, the application of CAR-T therapy for solid tumors has proven to be less effective due to challenges such as the varied antigens in solid tumors, an immunosuppressive tumor environment, limited immune cell infiltration, reduced CAR-T cell activity and toxicity issues. To solve these problems, scientists are making efforts to improve and improve the methods of treatment of solid tumors. Chemotherapy is the standard treatment for a large number of malignant neoplasms. It is also used before starting cell therapy for lymphodepletion and better engraftment of injected CAR-T cells. It has been shown that chemotherapy can reduce the immunosuppressive effect of the tumor microenvironment, destroy the stroma, and promote better infiltration of the tumor by CAR-T cells, improving their survival, persistence, cytotoxicity, and influencing the metabolism of immune cells inside the tumor. The effectiveness of combining chemotherapy and CAR-T cell therapy relies on various factors such as tumor type, dosage, treatment schedule, CAR-T cell composition, and individual biological traits. Similarly, radiation therapy can enhance tumor cell vulnerability to specific treatments while also supporting tumor cell survival.

In this review, we discuss the use of CAR-T therapy to combat solid tumors, regarding the challenges of treating solid tumors, ways to overcome them, and also touch upon the possibility of using combination treatments to improve the effectiveness of cell therapy.

Dark horse target Claudin18.2 opens new battlefield for pancreatic cancer

Pancreatic cancer is one of the deadliest malignant tumors, which is a serious threat to human health and life, and it is expected that pancreatic cancer may be the second leading cause of cancer death in developed countries by 2030. Claudin18.2 is a tight junction protein expressed in normal gastric mucosal tissues, which is involved in the formation of tight junctions between cells and affects the permeability of paracellular cells. Claudin18.2 is highly expressed in pancreatic cancer and is associated with the initiation, progression, metastasis and prognosis of cancer, so it is considered a potential therapeutic target. Up to now, a number of clinical trials for Claudin18.2 are underway, including solid tumors such as pancreatic cancers and gastric cancers, and the results of these trials have not yet been officially announced. This manuscript briefly describes the Claudia protein, the dual roles of Cluadin18 in cancers, and summarizes the ongoing clinical trials targeting Claudin18.2 with a view to integrating the research progress of Claudin18.2 targeted therapy. In addition, this manuscript introduces the clinical research progress of Claudin18.2 positive pancreatic cancer, including monoclonal antibodies, bispecific antibodies, antibody-drug conjugates, CAR-T cell therapy, and hope to provide feasible ideas for the clinical treatment of Claudin18.2 positive pancreatic cancer.

Ectopic CXCR2 expression cells improve the anti-tumor efficiency of CAR-T cells and remodel the immune microenvironment of pancreatic ductal adenocarcinoma

BACKGROUND

Recent progressions in CAR-T cell therapy against pancreatic ductal adenocarcinoma (PDAC) remain disappointing, which are partially attributed to the immunosuppressive microenvironment including macrophage-mediated T cell repletion.

METHODS

We first characterized the expression patterns of macrophage-relevant chemokines and identified CXCR2 as the key factor regulating T cell trafficking and tumor-specific accumulation in PDAC microenvironment. After that, we synthesized and introduced a CXCR2 expression cascade into Claudin18.2 CAR-T cells and compared the behaviors of CAR-T cells in vitro and in vivo. The therapeutic potential of CXCR2 CAR-T was evaluated in two different allogeneic models: subcutaneous allografts and metastatic PDAC models.

RESULTS

The results showed that CXCR2 CAR-T not only reduced the size of allografted PDAC tumors, but also completely eliminated the formation of metastases. Lastly, we investigated the tumor tissues and found that expression of ectopic CXCR2 significantly improved tumor-targeted infiltration and residence of T cells and reduced the presence of MDSCs and CXCR2 + macrophages in PDAC microenvironment.

CONCLUSION

Our studies suggested that ectopic CXCR2 played a significant and promising role in improving the efficiency of CAR-T therapy against primary and metastatic PDAC and partially reversed the immune-suppressive microenvironment.