MSLN (Mesothelin), ANTXR1 (TEM8), and MUC3A are the potent antigenic targets for CAR T cell therapy of gastric adenocarcinoma

CAR-T cell-derived exosomes: a new perspective for cancer therapy

Chimeric antigen receptor (CAR)-T cell adoptive immunotherapy is a promising cancer treatment that uses genetically engineered T cells to attack tumors. However, this therapy can have some adverse effects. CAR-T cell-derived exosomes are a potential alternative to CAR-T cells that may overcome some limitations. Exosomes are small vesicles released by cells and can carry a variety of molecules, including proteins, RNA, and DNA. They play an important role in intercellular communication and can be used to deliver therapeutic agents to cancer cells. The application of CAR-T cell-derived exosomes could make CAR-T cell therapy more clinically controllable and effective. Exosomes are cell-free, which means that they are less likely to cause adverse reactions than CAR-T cells. The combination of CAR-T cells and exosomes may be a more effective way to treat cancer than either therapy alone. Exosomes can deliver therapeutic agents to cancer cells where CAR-T cells cannot reach. The appropriate application of both cellular and exosomal platforms could make CAR-T cell therapy a more practicable treatment for cancer. This combination therapy could offer a safe and effective way to treat a variety of cancers.

Mesothelin CAR-T cells expressing tumor-targeted immunocytokine IL-12 yield durable efficacy and fewer side effects

Chimeric antigen receptor (CAR)-modified T cell therapy has achieved remarkable efficacy in treating hematological malignancies, but it confronts many challenges in treating solid tumors, such as the immunosuppressive microenvironment of the solid tumors. These factors reduce the antitumor activity of CAR-T cells in clinical trials. Therefore, we used the immunocytokine interleukin-12 (IL-12) to enhance the efficacy of CAR-T cell therapy. In this study, we engineered CAR-IL12R54 T cells that targeted mesothelin (MSLN) and secreted a single-chain IL-12 fused to a scFv fragment R54 that recognized a different epitope on mesothelin. The evaluation of the anti-tumor activity of the CAR-IL12R54 T cells alone or in combination with anti-PD-1 antibody in vitro and in vivo was followed by the exploration of the functional mechanism by which the immunocytokine IL-12 enhanced the antitumor activity. CAR-IL12R54 T cells had potency to lyse mesothelin positive tumor cells in vitro. In vivo studies demonstrated that CAR-IL12R54 T cells were effective in controlling the growth of established tumors in a xenograft mouse model with fewer side effects than CAR-T cells that secreted naked IL-12. Furthermore, combination of PD-1 blockade antibody with CAR-IL12R54 T cells elicited durable anti-tumor responses. Mechanistic studies showed that IL12R54 enhanced Interferon-γ (IFN-γ) production and dampened the activity of regulatory T cells (Tregs). IL12R54 also upregulated CXCR6 expression in the T cells through the NF-κB pathway, which facilitated T cell infiltration and persistence in the tumor tissues. In summary, the studies provide a good therapeutic option for the clinical treatment of solid tumors.

Cell-Surface GRP78-Targeted Chimeric Antigen Receptor T Cells Eliminate Lung Cancer Tumor Xenografts

Lung cancer is one of the most common and intractable malignancies. It is associated with low survival rates despite existing treatments, indicating that new and more effective therapies are urgently needed such as the chimeric antigen receptor-T (CAR-T) cell immunotherapy. The cell-surface glucose-regulated protein 78 (csGRP78) is expressed in various hematological malignancies and solid tumor cells including lung cancer in response to cancer-related endoplasmic reticulum stress, while GRP78 is restricted to inside the normal cells. Here, we detected the prominent expression of csGRP78 in both lung cancer cell lines, A549 and H1299, as well as cancer stemlike cells derived from A549 by immunofluorescence. Next, a csGRP78-targeted CAR was constructed, and the transduced CAR-T cells were tested for their potency to kill the two lung cancer cell lines and derived stemlike cells, which was correlated with specific interferon γ release in vitro. Finally, we found that csGRP78 CAR-T cells also efficiently killed both lung cancer cells and cancer stemlike cells, resulting into the elimination of tumor xenografts in vivo, neither with any evidence of relapse after 63 days of tumor clearance nor any detrimental impact on other body organs we examined. Our study reveals the capacity of csGRP78 as a therapeutic target and offers valuable insight into the development of csGRP78 CAR-T cells as potential therapy for lung cancer.

Cancer-associated fibroblasts impair the cytotoxic function of NK cells in gastric cancer by inducing ferroptosis via iron regulation

As the predominant immunosuppressive component within the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) inhibit Natural Killer cell (NK cell) activity to promote tumor progression and immune escape; however, the mechanisms of cross-talk between CAFs and NK cells in gastric cancer (GC) remain poorly understood. In this study, we demonstrate that NK cell levels are inversely correlated with CAFs abundance in human GC. CAFs impair the anti-tumor capacity of NK cells by inducing ferroptosis, a cell death process characterized by the accumulation of iron-dependent lipid peroxides. CAFs induce ferroptosis in NK cells by promoting iron overload; conversely, decreased intracellular iron levels protect NK cells against CAF-induced ferroptosis. Mechanistically, CAFs increase the labile iron pool within NK cells via iron export into the TME, which is mediated by the upregulated expression of iron regulatory genes ferroportin1 and hephaestin in CAFs. Moreover, CAF-derived follistatin like protein 1(FSTL1) upregulates NCOA4 expression in NK cells via the DIP2A-P38 pathway, and NCOA4-mediated ferritinophagy is required for CAF-induced NK cell ferroptosis. In a human patient-derived organoid model, functional targeting of CAFs using a combination of deferoxamine and FSTL1-neutralizing antibody significantly alleviate CAF-induced NK cell ferroptosis and boost the cytotoxicity of NK cells against GC. This study demonstrates a novel mechanism of suppression of NK cell activity by CAFs in the TME and presents a potential therapeutic approach to augment the immune response against GC mediated by NK cells.

Mesothelin-targeted CAR-T therapy combined with irinotecan for the treatment of solid cancer

BACKGROUND

Chimeric antigen receptor (CAR) T cell therapy has shown promising results in treating blood cancers, but it has limited efficacy against solid tumors that express mesothelin (MSLN). One of the reasons is the immunosuppressive tumor microenvironment, which consists of physical barriers, multiple mechanisms of immune evasion, and various biochemical factors that favor tumor growth and survival. These factors reduce the antitumor activity of MSLN-targeted CAR T cells in clinical trials. Therefore, new therapeutic strategies are needed to enhance the effectiveness of MSLN-targeted CAR T cell therapy.

METHODS

To investigate whether the antitumor efficacy of anti-MSLN CAR-T cells depends on the epitopes they recognize, we generated MSLN-targeted CAR T cells that bind to different regions of MSLN (Region I, II, III and Full length). We then evaluated the antitumor activity of MSLN-targeted CAR T cells alone or in combination with the chemotherapeutic drug irinotecan or an anti-PD-1 antibody in vitro and in vivo.

RESULTS

We found that MSLN-targeted CAR T cells effectively killed MSLN-positive cancer cells (H9, H226 and Panc-1), but not MSLN-negative cells (A431) in vitro. In a mouse model of H9 tumor xenografts, all CAR T cells showed similar tumor suppression, but an MSLN-targeted scFv with Region I epitope, R47, performed slightly better. Combining irinotecan with CAR_R47 T cells enhanced tumor control synergistically in both H9 xenograft mice and patient-derived xenograft mice.

CONCLUSIONS

Our results suggest that irinotecan can enhance the antitumor activity of MSLN-targeted CAR T cells, and offer a promising combination therapy strategy for MSLN-positive solid tumors.

CAR designs for solid tumors: overcoming hurdles and paving the way for effective immunotherapy

Chimeric antigen receptor T cell (CAR-T) therapy has revolutionized immunotherapy by modifying patients' immune cells genetically. By expressing CARs, these modified cells can specifically identify and eliminate tumor cells. The success of CAR-T therapy in hematological malignancies, such as leukemia and lymphoma, has been remarkable. Numerous studies have reported improved patient outcomes and increased survival rates. However, the application of CAR-T therapy in treating solid tumors faces significant challenges. Solid tumors possess complex microenvironments containing stromal cells, extracellular matrix components, and blood vessels. These factors can impede the infiltration and persistence of CAR-T cells within the tumor. Additionally, the lack of target antigens exclusively expressed on tumor cells raises concerns about off-target effects and potential toxicity. This review aims to discuss advancements achieved by CAR-T therapy in solid tumors and the clinical outcomes in the realm of solid tumors.

Advances and key focus areas in gastric cancer immunotherapy: A comprehensive scientometric and clinical trial review (1999-2023)

BACKGROUND

Gastric cancer (GC) is the sixth most common cancer and third leading cause of cancer-related deaths worldwide. Current treatments mainly rely on surgery- and chemotherapy-based systemic; however, the prognosis remains poor for advanced disease. Recent studies have suggested that immunotherapy has significant potential in cancer therapy; thus, GC immunotherapy may improve quality of life and survival for patients with this disease.

AIM

To provide a comprehensive overview of the knowledge structure and research hotspots of GC immunotherapy.

METHODS

We conducted a bibliometric analysis of publications on immunotherapy related to GC in the Web of Science Core Collection database. We analyzed 2013 pub-lications from 1999 to February 1, 2023, using the VOSviewer and CiteSpace software. We assessed publication and citation distributions using the WoS platform and explored research countries, institutions, journals, authors, references, and keywords (co-occurrence, timeline view, and burst analysis). In addition, we examined 228 trials on immunotherapy, 137 on adoptive cell therapy, 274 on immune checkpoint inhibitors (ICIs), and 23 on vaccines from ClinicalTrials.gov and the International Clinical Trials Registry Platform. The Impact Index Per Article for the top ten high-cited papers collected from Reference Citation Analysis (RCA) are presented.

RESULTS

Our bibliometric analysis revealed that the study of immunotherapy in GC has developed rapidly in recent years. China accounted for almost half the publications, followed by the United States. The number of publications in recent years has been growing continuously, and most institutions and authors with the most publications are from China. The main keywords or clusters identified were "tumor microenvironment", "adoptive immunotherapy", "dendritic therapy", and "microsatellite instability".

CONCLUSION

Our analysis of 2013 publications indicated that immunotherapy for GC has led to several new developments in recent years. Considerable progress has been made in vaccinations, immune checkpoint therapy, and adoptive cellular therapy. In particular, ICIs and chimeric antigen receptor T-cells are novel options for the treatment of GC. We suggest that the combination of ICIs, chemotherapy, targeted therapy, and other immunotherapies should be the primary research direction in the future.

Mucin Glycans: A Target for Cancer Therapy

Mucin glycans are an important component of the mucus barrier and a vital defence against physical and chemical damage as well as pathogens. There are 20 mucins in the human body, which can be classified into secreted mucins and transmembrane mucins according to their distributions. The major difference between them is that secreted mucins do not have transmembrane structural domains, and the expression of each mucin is organ and cell-specific. Under physiological conditions, mucin glycans are involved in the composition of the mucus barrier and thus protect the body from infection and injury. However, abnormal expression of mucin glycans can lead to the occurrence of diseases, especially cancer, through various mechanisms. Therefore, targeting mucin glycans for the diagnosis and treatment of cancer has always been a promising research direction. Here, we first summarize the main types of glycosylation (O-GalNAc glycosylation and N-glycosylation) on mucins and the mechanisms by which abnormal mucin glycans occur. Next, how abnormal mucin glycans contribute to cancer development is described. Finally, we summarize MUC1-based antibodies, vaccines, radio-pharmaceuticals, and CAR-T therapies using the best characterized MUC1 as an example. In this section, we specifically elaborate on the recent new cancer therapy CAR-M, which may bring new hope to cancer patients.

Decoding the expression pattern of MUC3A in gastric adenocarcinoma: unveiling the key to successful immunotherapy

AIMS

Despite the promise of immunotherapy for gastric adenocarcinoma, resistance is common, necessitating the validation of new targets. Based on our previous bioinformatics analysis, the MUC3A antigen emerged as a promising candidate for immunotherapy against gastric adenocarcinoma. However, a comprehensive understanding of its expression at protein level remains elusive, despite its crucial role in determining clinical response. We also sought to establish a connection between the expression pattern and relevant clinical variables of the disease, whenever feasible.

METHODS

Immunohistochemistry was used to determine the percentage of MUC3A-positive tumor cells in primary (PT) and metastatic tumor (MT) sites of 190 gastric adenocarcinoma patients. We also evaluated the association between MUC3A expression and variables such as Lauren classification, history of neoadjuvant chemotherapy and/or radiotherapy, and overall patient survival.

RESULTS

Median MUC3A expression was 50% in PT and 70% in MT sites, exhibiting a positive correlation. MT intestinal type showed significantly higher MUC3A expression compared to other types. Neoadjuvant therapy history did not affect MUC3A expression. Higher MUC3A expression correlated with improved survival.

CONCLUSIONS

Based on our previous bioinformatics data and the consistently high expression of MUC3A on gastric tumor cells, we propose advancing experimental aspects of anti-MUC3A immunotherapy for gastric adenocarcinoma.

Challenges of Anti-Mesothelin CAR-T-Cell Therapy

Chimeric antigen receptor (CAR)-T-cell therapy is a kind of adoptive T-cell therapy (ACT) that has developed rapidly in recent years. Mesothelin (MSLN) is a tumor-associated antigen (TAA) that is highly expressed in various solid tumors and is an important target antigen for the development of new immunotherapies for solid tumors. This article reviews the clinical research status, obstacles, advancements and challenges of anti-MSLN CAR-T-cell therapy. Clinical trials on anti-MSLN CAR-T cells show that they have a high safety profile but limited efficacy. At present, local administration and introduction of new modifications are being used to enhance proliferation and persistence and to improve the efficacy and safety of anti-MSLN CAR-T cells. A number of clinical and basic studies have shown that the curative effect of combining this therapy with standard therapy is significantly better than that of monotherapy.

Current advances and challenges in CAR T-Cell therapy for solid tumors: tumor-associated antigens and the tumor microenvironment

The past decade has witnessed ongoing progress in immune therapy to ameliorate human health. As an emerging technique, chimeric antigen receptor (CAR) T-cell therapy has the advantages of specific killing of cancer cells, a high remission rate of cancer-induced symptoms, rapid tumor eradication, and long-lasting tumor immunity, opening a new window for tumor treatment. However, challenges remain in CAR T-cell therapy for solid tumors due to target diversity, tumor heterogeneity, and the complex microenvironment. In this review, we have outlined the development of the CAR T-cell technique, summarized the current advances in tumor-associated antigens (TAAs), and highlighted the importance of tumor-specific antigens (TSAs) or neoantigens for solid tumors. We also addressed the challenge of the TAA binding domain in CARs to overcome off-tumor toxicity. Moreover, we illustrated the dominant tumor microenvironment (TME)-induced challenges and new strategies based on TME-associated antigens (TMAs) for solid tumor CAR T-cell therapy.

Interleukin-15 and chemokine ligand 19 enhance cytotoxic effects of chimeric antigen receptor T cells using zebrafish xenograft model of gastric cancer

Chimeric antigen receptor (CAR) T cells have been proven effective for the treatment of B-cell-mediated malignancies. Currently, the development of efficient tools that supply CAR T cells for the treatment of other malignancies would have great impact. In this study, interleukin (IL)-15 and C-C motif chemokine ligand 19 (CCL19) were introduced into natural killer group 2D (NKG2D)-based CARs to generate 15×19 CAR T cells, which remarkably increased T-cell expansion and promoted the production of central memory T (T_cm) cells. 15×19 CAR T cells showed greater cytotoxicity to gastric cell lines than conventional CAR T cells and produced higher levels of IL-15 and CCL-19, which resulted in increased responder T cell chemotaxis and reduced expression of T cell exhaustion markers. A live zebrafish model was used for single-cell visualization of local cytotoxicity and metastatic cancers. Administration of 15×19 CAR T cells resulted in significant shrinking of gastric cancer xenograft tumors and expansion of 15×19 CAR T cells in zebrafish models. Taken together, these findings demonstrate that 15×19 CAR T cells are highly efficient in killing gastric cancer cells, are effective to avoid off-target effects, and migrate to local and metastatic sites for long-term surveillance of cancers.

From Anti-HER-2 to Anti-HER-2-CAR-T Cells: An Evolutionary Immunotherapy Approach for Gastric Cancer

Current Therapeutic modalities provide no survival advantage to gastric cancer (GC) patients. Targeting the human epidermal growth factor receptor-2 (HER-2) is a viable therapeutic strategy against advanced HER-2 positive GC. Antibody-drug conjugates, small-molecule tyrosine kinase inhibitors (TKIs), and bispecific antibodies are emerging as novel drug forms that may abrogate the resistance to HER-2-specific drugs and monoclonal antibodies. Chimeric antigen receptor-modified T cells (CAR-T) targeting HER-2 have shown considerable therapeutic potential in GC and other solid tumors. However, due to the high heterogeneity along with the complex tumor microenvironment (TME) of GC that often leads to immune escape, the immunological treatment of GC still faces many challenges. Here, we reviewed and discussed the current progress in the research of anti-HER-2-CAR-T cell immunotherapy against GC.

MUC3A promotes the progression of colorectal cancer through the PI3K/Akt/mTOR pathway

Mucin 3A (MUC3A) is overexpressed in colorectal cancer (CRC) and associated with poor prognosis, but the related mechanism remains unclear. Our study found that MUC3A promotes the progression of CRC by activating the PI3K/Akt/mTOR signaling pathway. Knockout of MUC3A significantly inhibited the proliferation of CRC cells and induced G1 phase arrest by upregulating p21 protein, an important cell cycle regulator. Moreover, knockout of MUC3A significantly inhibited invasion ability and enhanced the sensitivity to the chemotherapeutic agent 5-FU. Furthermore, we found that knockout of MUC3A repressed the PI3K/Akt/mTOR pathway through RNA-seq. Treatment with the PI3K/Akt/mTOR pathway inhibitor rapamycin successfully eliminated the difference in proliferation, invasion and chemoresistance between MUC3A knockout cells and control cells. Our study suggests that MUC3A is a potential oncogene that promotes the proliferation, invasion, and chemotherapy resistance of CRC. Moreover, CRC patients with high expression of MUC3A may benefit from rapamycin treatment. 

Interpatient variability in mesothelin expression necessitates its evaluation before gastric cancer immunotherapy

Aims: Mesothelin (MSLN) was applied for the immunotherapy of ovarian cancer and mesothelioma with a minimum expression of 60% to obtain a clinical response. Here, the authors evaluated MSLN expression as a potential target of gastric adenocarcinoma immunotherapy. Materials & methods: The expression of MSLN was evaluated by immunohistochemistry and was reported in primary tumor (PT) and metastatic tumor (MT) sites. Results: The results showed that only 17.1% and 13.5% of the patients had 60% or more MSLN expression in PT and MT sites, respectively. The expression of MSLN in PTs and MTs was not influenced by Lauren classification, neoadjuvant therapy or tumor stage. Conclusions: Interpatient variability in MSLN expression necessitates its evaluation before MSLN-based gastric cancer immunotherapy.

CAR-T cell therapy for lung cancer: Potential and perspective

Lung cancer is the highest incidence and mortality of all cancers around the world. In the present immunotherapy era, an increasing number of immunotherapeutic agents including monoclonal antibody‐targeted drugs have been used in the clinical treatment of malignancy, but it still has many limitations. Chimeric antigen receptor‐modified T (CAR‐T) cells, a novel adoptive immunotherapy strategy, have not only been used successfully against hematological tumors, but have also opened up new avenues for immunotherapy of solid tumors, including lung cancer. However, targeting lung cancer‐specific antigens using engineered CAR‐T cells is complicated by the lack of proper tumor‐specific antigens, an immunosuppressive tumor microenvironment, a low level of CAR‐T cell infiltration into tumor tissues, along with off‐target effect, etc. Simultaneously, the clinical application of CAR‐T cells remains limited because of many challenges such as tumor lysis syndrome, neurotoxicity syndrome, and cytokine release syndrome. In this review, we outline the basic structure and generation characteristic of CAR‐T cells and summarize the common tumor‐associated antigens in clinical trials of CAR‐T cell therapy for lung cancer, and point out the current challenges and new strategies, aiming to provide new ideas and approaches for the pre‐clinical experiments and clinical trials of CAR‐T cell therapy in lung cancer.

ANTXR1 as a potential prognostic biomarker for hepatitis B virus-related hepatocellular carcinoma identified by a weighted gene correlation network analysis

BACKGROUND

With high incidence and mortality rates, hepatocellular carcinoma (HCC) is one of the most prevalent malignant tumors worldwide. Chronic hepatitis B virus (HBV) infection is a leading cause of HCC, especially for Asians and blacks. However, the molecular mechanisms underlying HBV-related HCC are unclear. This study sought to identify novel prognostic biomarkers and explore the potential pathogenesis of HBV-related HCC.

METHODS

The gene expression profiles and corresponding clinical information of HCC from The Cancer Genome Atlas Liver Hepatocellular Carcinoma data set were analyzed by a weighted gene co-expression network analysis. Correlations between the co-expression modules and clinical traits were calculated. Next, key modules associated with HBV infection were identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were conducted for the genes in the key modules. The hub genes were identified based on the protein-protein interaction (PPI) network via the Cytoscape. Finally, an overall survival (OS) analysis was performed.

RESULTS

The two modules (i.e., the brown and yellow modules) most relevant to HBV infection were constructed. A functional enrichment analysis revealed that the genes in the two modules were mainly enriched in HCC-related pathways, such as the phosphatidylinositol-3-kinase and protein kinase B signaling pathway, focal adhesion, human papillomavirus infection, the Rap1 signaling pathway, and the cyclic guanosine monophosphate-dependent protein kinase (cGMP-PKG) signaling pathway. Ten hub genes [i.e., COL3A1, ANTXR1, COL14A1, THBS2, ADAMTS2, AEBP1, PRELP, EMILIN1, DCN and PODN] in the brown module, and 10 hub genes [i.e., USP34, SEC24C, ZNF770, STAG1, TSTD2, PKD1P6, CCNK, GFT2I, NT5C2 and SMG6] in the yellow module were identified. Among the hub genes, ANTXR1 (Anthrax-toxin receptor 1) was significantly correlated with HBV-related HCC patients' OS.

CONCLUSIONS

ANTXR1 represents a potential therapeutic target for HBV-related HCC. This study offers novel insights into the molecular mechanisms of HBV-induced tumorigenesis, which needs to be further validated by basic experiments and large-scale cohort studies.

KLF7 Promotes Gastric Carcinogenesis Through Regulation of ANTXR1

PURPOSE

Elucidating the mechanism of gastric cancer progression is of great importance for the discovery of new therapy targets against gastric cancer. In this study, we investigated the function of Kruppel-like factor 7 (KLF7) in gastric cancer.

METHODS

qPCR and Western blot were performed to determine the expression of ANTXR1 after KLF7 inhibition. CCK-8, colony formation, apoptosis analysis, cell cycle analysis and transwell assay were performed to determine KLF7 functions in cellular proliferation, migration, apoptosis and cell cycle. Tumour xenograft experiments were performed to examine cell growth in vivo.

RESULTS

The results showed that KLF7 was upregulated in gastric cancer. The proliferation and migration of gastric cancer cells were suppressed by depletion of KLF7. In vivo tumour progression was also attenuated following the downregulation of KLF7. Meanwhile, overexpression of KLF7 promoted the proliferation and migration of gastric cancer cells. The results of the mechanistic analysis showed that KLF7 promoted gastric carcinogenesis via upregulation of ANTXR cell adhesion molecule 1 (ANTXR1).

CONCLUSION

Therefore, this study may provide a theoretical foundation for further clinical therapy of gastric cancer.

Novel antigens of CAR T cell therapy: New roads; old destination

Chimeric antigen receptor T cell (CAR-T) therapy has so far proved itself as a reliable therapeutic option for the treatment of relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL), diffuse large B-cell lymphoma (DLBCL), multiple myeloma (MM), and mantle cell lymphoma (MCL). However, this picture is not as colorful when it comes to the treatment of solid tumors mainly due to the lack of definitive tumor antigens, as well as the immunosuppressive tumor microenvironments and poor CAR-T infiltration. The recent developments in bioinformatics and cell biology, such as single-cell RNA sequencing, have offered silver linings in the subject of tumor antigen discovery. In the current review, we summarize the development of some CAR-T therapies that target novel tumor antigens, rather than the traditionally CAR-T-targeted ones, and briefly discuss the clinical antitumor achievements of those evaluated in patients, so far. Furthermore, we propose some tumor antigens that might someday be therapeutically beneficial while targeted by CAR-Ts based on the experimental evaluations of their specific monoclonal antibodies.

Latest therapeutic target for gastric cancer: Anthrax toxin receptor 1

Anthrax toxin receptor 1 (ANTXR1), also known as tumor endothelial marker 8, is a highly conserved cell surface protein overexpressed in tumor-infiltrating vessels. It was first found in vascular endothelial cells of human colorectal cancer. Although our understanding of its physiological function is limited, it has been found that ANTXR1 binds collagen and promotes migration of endothelial cells in vitro. ANTXR1 is upregulated in vessels of different tumor types in mice and humans, and is also expressed by tumor cells themselves in some tumors, such as gastric, lung, intestinal and breast cancer. Developmental angiogenesis and wound healing were not disturbed in ANTXR1 knockout mice, but compared with wild-type mice, growth of melanoma was impaired after ANTXR1 knockout, indicating that host-derived ANTXR1 can promote tumor growth on the basis of immune activity. Previous studies have shown that ANTXR1 vaccines or sublethal doses of anthrax toxin can inhibit angiogenesis, slow tumor growth and prolong survival. These studies suggest that ANTXR1 is necessary for tumor rather than physiological angiogenesis. It has been found that ANTXR1 plays an important role in tumor angiogenesisas well as in the growth and metastasis of many kinds of tumors. This article reviews the physiological function of ANTXR1 and its role in different kinds of cancer.

Research advances in chimeric antigen receptor-modified T-cell therapy (Review)

Chimeric antigen receptor (CAR)-modified T-cells are T-cells that have been genetically engineered to express CAR molecules to target specific surface antigens on tumor cells. CAR T-cell therapy, a novel cancer immunotherapy, has been attracting increasing attention, since it exhibited notable efficacy in the treatment of hematological tumors in clinical trials. However, for this type of therapy, challenges must be overcome in the treatment of solid tumors. Furthermore, certain side effects associated with CAR T-cell therapy, including cytokine release syndrome, immune effector cell-related neurotoxicity syndrome, tumor lysis syndrome and on-target off-tumor toxicity, must be taken into consideration. The present study provides a systematic review of the principle, clinical application, current challenges, possible solutions and future perspectives for CAR T-cell therapy.

KIAA1429 promotes the progression of lung adenocarcinoma by regulating the m6A level of MUC3A

OBJECTIVE

Lung adenocarcinoma (LUAD) is one of the most frequently occurring human malignancies worldwide, but its potential molecular mechanism has not yet been fully elucidated. N6-methyladenosine (m6A), the most common internal chemical modification of mRNAs, is implicated in diverse pathological processes in different human malignancies, but its functions in LUAD remain elusive. The current study aimed to investigate the function and molecular mechanism of KIAA1429 in LUAD.

METHODS

The KIAA1429 expression level in LUAD tissues was assessed using databases and was detected in LUAD cells and tissues via quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot. m6A levels in LUAD tissues and cells were quantified. Next, correlation between the KIAA1429 expression level and the clinical and pathological features and prognosis of patients with LUAD was analyzed. Further, KIAA1429 levels were decreased, and LUAD cell proliferation, migration, invasion, and cycle were assessed. Prediction websites revealed the aberrant expression and probable methylation modification of MUC3A in LUAD, and correlation between MUC3A and KIAA1429 was analyzed. Ultimately, the impact of the KIAA1429 expression on MUC3A-mediated malignant phenotypes of LUAD was examined by a torsion test.

RESULTS

KIAA1429 expression was remarkably high and m6A level was aberrantly elevated in LUAD cells and tissues. In addition, high KIAA1429 expression indicated a larger tumor diameter, higher tumor-node-metastasis stage, greater proneness to lymph node and distant metastasis, and lower overall survival rate. siRNA-triggered KIAA1429 downregulation dramatically suppressed LUAD cell proliferation, migration, invasion, and cell cycle arrest in the G1 phase. Bioinformatics analysis revealed that MUC3A was expressed in LUAD at an unusually high level and may be methylated under the control of KIAA1429. Western blot, qRT-PCR, and correlation analyses revealed a positive correlation between KIAA1429 expression level and MUC3A. Finally, torsion test results revealed that low KIAA1429 expression reversed LUAD cell migration, proliferation, and invasion facilitated by low MUC3A expression as well as cell cycle arrest in the G1 phase.

CONCLUSION

KIAA1429 exhibited an unusually high expression in LUAD cells and tissues, and high KIAA1429 expression was correlated with the clinical and pathological features of patients with LUAD, thereby leading to an unsatisfactory prognosis. Furthermore, KIAA1429 regulates MUC3A expression through m6A modification to modulate LUAD cells to proliferate, migrate, invade, and induce cell cycle arrest.

Mesothelin-targeted CAR-T cell therapy for solid tumors

Introduction: Mesothelin (MSLN) is a tumor differentiation antigen normally restricted to the body's mesothelial surfaces, but significantly overexpressed in a broad range of solid tumors. For this reason, MSLN has emerged as an important target for the development of novel immunotherapies. This review focuses on anti-MSLN chimeric antigen receptor (CAR) T cell immunotherapy approaches.Areas covered: A brief overview of MSLN as a therapeutic target and existing anti-MSLN antibody-based drugs and vaccines is provided. A detailed account of anti-MSLN CAR-T cell approaches utilized in preclinical models is presented. Finally, a comprehensive summary of currently ongoing and completed anti-MSLN CAR-T cell clinical trials is discussed.Expert opinion: Initial trials using anti-MSLN CAR-T cells have been safe, but efficacy has been limited. Employing regional routes of delivery, introducing novel modifications leading to enhanced tumor infiltration and persistence, and improved safety profiles and combining anti-MSLN CAR-T cells with standard therapies, could render them more efficacious in the treatment of solid malignancies.

Association of genetic variants in the 3'-untranslated region of the mesothelin (MSLN) gene with ovarian carcinoma

Limited information has been offered regarding the association of mesothelin (MSLN) gene variants at the 3'-untranslated region with the risk of ovarian carcinoma. The primary objective of this work is to assess the impact of the MSLN (rs1057147 and rs57272256) variants on the progression of ovarian carcinoma among Egyptian women. The study was conceived based on 127 women diagnosed with ovarian carcinoma and 106 unrelated cancer-free controls. Genomic DNA of these MSLN variants was genotyped utilizing the PCR technique. The frequencies of the MSLN (rs1057147) variant revealed a significant association with increased risk of ovarian carcinoma under allelic and dominant models (P < .05). Nonetheless, ovarian cancer patients with the MSLN (rs57272256) variant did not attain considerable significance under all genetic models (P > .05). Together, our findings suggested that the MSLN (rs1057147) variant was associated with an increased risk of ovarian carcinoma, but not the MSLN (rs57272256) variant.

Serum mucin 3A as a potential biomarker for extrahepatic cholangiocarcinoma

BACKGROUND/AIMS

The aim of this study is to evaluate serum mucin 3A (MUC3A) as a candidate biomarker for extrahepatic cholangiocarcinoma (EHCC).

PATIENTS AND METHODS

35 Patients with EHCC, 30 patients with pancreatic cancer, 35 patients with gallbladder carcinoma and 78 patients with benign biliary disease were enrolled during January 2015 to January 2016. Serum MUC3A, carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) were measured in these patients. Pathology reports of patients with EHCC were collected.

RESULTS

(1) The serum levels of MUC3A (87.3 ± 10.8 ng/ml) in patients with EHCC were higher than in patients with pancreatic cancer (63.2 ± 7.7 ng/ml, P < 0.001), patients with gallbladder carcinoma (59.0 ± 10.3 ng/ml, P < 0.001) and patients with benign biliary disease (56.6 ± 13.1 ng/ml, P < 0.001). (2) ROC analysis showed that using MUC3A could clearly distinguish patients with EHCC from those without EHCC with a threshold of 73.2 ng/ml. (3) According to ROC analysis, the sensitivity, specificity, and accuracy of serum MUC3A for diagnosis of EHCC were 94.3%, 89.5% and 90.4%, respectively, which were all significantly higher than CA19-9 and CEA. (4) The serum levels of MUC3A at 1 month post-operatively in 35 patients with EHCC were decreased compared to pre-operative levels (51.8 ± 5.6 vs. 87.3 ± 10.8 ng/ml, P < 0.01). (5) Compared with 20 patients with low MUC3A levels (≤88.8 ng/ml), 15 patients with high MUC3A levels (>88.8 ng/ml) had higher percentage of lymph node metastasis (66.7% vs. 25%, P = 0.014), surrounding tissue infiltration (80% vs. 30%, P = 0.003), and UICC staging IIa-III (86.7% vs. 35%, P = 0.002).

CONCLUSION

The diagnostic efficiency for EHCC of MUC3A is obviously superior to CA19-9 and CEA, and a high level of serum MUC3A indicates a poor prognosis, therefore, MUC3A can be used as a potential diagnostic and prognostic biomarker for EHCC.

The relationship between TEM8 and early diagnosis and prognosis of lung cancer

BACKGROUND

To explore the TEM8 expression in patients with lung cancer and its relationship with clinical pathology and prognosis, and to analyze the diagnostic value of TEM8.

METHODS

A total of 204 patients with lung cancer diagnosed and treated in Zhongmeng Hospital Zhalantun and the First Affiliated Hospital of Jinzhou Medical University from March 2013 to February 2016 were enrolled in the study group, and 203 healthy subjects in the control group. qRT-PCR technique was applied to detect the TEM8 expression. Combined with clinical information, the diagnostic value of TEM8 for lung cancer and the correlation of clinical characteristics of TEM8 were analyzed. The 3-year survival curves of patients with low and high TEM8 expressions were compared.

RESULTS

The expression in the study group was significantly higher than that in the control group (P<0.05). When the cut-off value was 1.125, the sensitivity, specificity and AUC of TEM8 in the diagnosis of lung cancer were 50.00%, 98.00% and 0.726 respectively. The TEM8 expression also differs when in smoking, lymphatic metastasis, TNM stage, differentiation degree and pleural invasion classification (P<0.050). 132 patients were included in the survival group and 72 patients were included in the death group. There was a difference between the two groups in the effect of TEM8 on the prognosis (P<0.001).

CONCLUSIONS

TEM8 showed high expression in the study group. TEM8 had good diagnostic efficacy and was expected to be an excellent indicator for early clinical diagnosis and prognosis of lung cancer.

Anthrax toxin receptor 1/tumor endothelial marker 8 promotes gastric cancer progression through activation of the PI3K/AKT/mTOR signaling pathway

Anthrax toxin receptor 1 (ANTXR1), a type I transmembrane protein, is one of the receptors that facilitates the entrance of anthrax toxin into cells. Previous studies have confirmed the pivotal role of ANTXR1 in progression and tumorigenesis of diverse cancer types. However, the biological function of ANTXR1 in gastric cancer (GC) is still unknown. The present study aimed to investigate the role of ANTXR1 in GC and illuminate the potential molecular mechanisms. Bioinformatics analysis found that ANTXR1 expression was significantly upregulated in GC tissue and its overexpression was associated with poor prognosis of GC patients. Moreover, we confirmed the upregulation of ANTXR1 in GC cell lines and GC tissue by quantitative PCR, western blot analysis, and immunohistochemical analysis. Additionally, high protein expression level of ANTXR1 was positively associated with several clinicopathological parameters in GC patients. In our study, a series of in vitro and in vivo assays were undertaken through strategies of loss/gain‐of‐function and rescue assays. Consequently, our results indicated that ANTXR1 induced proliferation, cell cycle progression, invasion and migration, and tumorigenicity and induced suppressed apoptosis in GC. Mechanistic investigation indicated that ANTXR1 exerted its promoting effects on GC through activation of the PI3K/AKT/mTOR signaling pathway. In conclusion, our findings suggested that ANTXR1 plays a crucial role in the development and progression of GC and could serve as a novel prognostic biomarker and potential therapeutic target for GC.

ANTXR1 (TEM8) overexpression in gastric adenocarcinoma makes the protein a potential target of immunotherapy

BACKGROUND

Despite the promise of immunotherapy for gastric adenocarcinoma, choices for the selection of effective antigenic targets are very limited. Previously published data and our own in-house computational analysis have suggested that ANTXR1 is a potential target, simultaneously expressed in malignant tumor cells and the endothelial cells of the tumors. However, the expression pattern of ANTXR1 protein in clinical samples of gastric adenocarcinoma has not been fully evaluated.

METHODS

Using immunohistochemistry (IHC), we recorded the percentage of ANTXR1 positive cells separately in tumor cells and endothelial cells in the primary tumor, non-tumor gastric tissue adjacent to the primary tumor, and tumor in metastatic sites of 140 gastric adenocarcinoma patients. We also evaluated the association of ANTXR1 expression with the Lauren histological classification of the primary tumors, the patient's history of neoadjuvant chemotherapy and/or radiotherapy, and the patient's overall survival.

RESULTS

ANTXR1 was expressed in a mean of 73.89 ± 30.12% of tumor cells and 13.55 ± 20.53% of endothelial cells in the primary tumors. Intestinal adenocarcinomas had lower ANTXR1 expression in the tumor cells and higher ANTXR1 expression in the endothelial cells of the tumor regions, and a history of neoadjuvant therapy was associated with increased ANTXR1 expression in the endothelial cells of the tumor regions. Finally, above median expression of ANTXR1 in the tumor cells of the tumor regions was associated with significantly lower overall patient survival.

CONCLUSIONS

Our findings suggest that ANTXR1 is a promising candidate for preclinical and clinical evaluation for gastric adenocarcinoma immunotherapy.

The Anthrax Toxin Receptor 1 (ANTXR1) Is Enriched in Pancreatic Cancer Stem Cells Derived from Primary Tumor Cultures

Pancreatic ductal adenocarcinoma (PDAC) is currently the fourth leading cause of cancer-related mortality. Cancer stem cells (CSCs) have been shown to be the drivers of pancreatic tumor growth, metastasis, and chemoresistance, but our understanding of these cells is still limited by our inability to efficiently identify and isolate them. While a number of markers capable of identifying pancreatic CSCs (PaCSCs) have been discovered since 2007, there is no doubt that more markers are still needed. The anthrax toxin receptor 1 (ANTXR1) was identified as a functional biomarker of triple-negative breast CSCs, and PDAC patients stratified based on ANTXR1 expression levels showed increased mortality and enrichment of pathways known to be necessary for CSC biology, including TGF-β, NOTCH, Wnt/β-catenin, and IL-6/JAK/STAT3 signaling and epithelial to mesenchymal transition, suggesting that ANTXR1 may represent a putative PaCSC marker. In this study, we show that ANTXR1⁺ cells are not only detectable across a panel of 7 PDAC patient-derived xenograft primary cultures but ANTXR1 expression significantly increased in CSC-enriched 3D sphere cultures. Importantly, ANTXR1⁺ cells also coexpressed other known PaCSC markers such as CD44, CD133, and autofluorescence, and ANTXR1⁺ cells displayed enhanced CSC functional and molecular properties, including increased self-renewal and expression of pluripotency-associated genes, compared to ANTXR1⁻ cells. Thus, this study validates ANTXR1 as a new PaCSC marker and we propose its use in identifying CSCs in this tumor type and its exploitation in the development of CSC-targeted therapies for PDAC.

Mesothelin is a target of chimeric antigen receptor T cells for treating gastric cancer

BACKGROUND

Gastric cancer (GC) is a common cancer in Asia and currently lacks a targeted therapy approach. Mesothelin (MSLN) has been reported to be expressed in GC tissue and could be targeted by chimeric antigen receptor (CAR) T cells. Mesothelin targeting CAR-T has been reported in mesothelioma, lung cancer, breast cancer, and pancreas cancer. However, the feasibility of using anti-MSLN CAR T cells to treat GC remains to be studied.

METHODS

We verified MSLN expression in primary human GC tissues and GC cell lines and then redirected T cells with a CAR containing the MSLN scFv (single-chain variable fragment), CD3ζ, CD28, and DAP10 intracellular signaling domain (M28z10) to target MSLN. We evaluated the function of these CAR T cells in vitro in terms of cytotoxicity, cytokine secretion, and surface phenotype changes when they encountered MSLN+ GC cells. We also established four different xenograft GC mouse models to assess in vivo antitumor activity.

RESULTS

M28z10 T cells exhibited strong cytotoxicity and cytokine-secreting ability against GC cells in vitro. In addition, cell surface phenotyping suggested significant activation of M28z10 T cells upon target cell stimulation. M28z10 T cells induced GC regression in different xenograft mouse models and prolonged the survival of these mice compared with GFP-transduced T cells in the intraperitoneal and pulmonary metastatic GC models. Importantly, peritumoral delivery strategy can lead to improved CAR-T cells infiltration into tumor tissue and significantly suppress the growth of GC in a subcutaneous GC model.

CONCLUSION

These results demonstrate that M28z10 T cells possess strong antitumor activity and represent a promising therapeutic approach to GC.