Gastrin Vaccine Alone and in Combination With an Immune Checkpoint Antibody Inhibits Growth and Metastases of Gastric Cancer

An update to experimental and clinical aspects of tumor-associated macrophages in cancer development: hopes and pitfalls

Tumor-associated macrophages (TAMs) represent one of the most abundant tumor-infiltrating stromal cells, and their normal function in tumor microenvironment (TME) is to suppress tumor cells by producing cytokines which trigger both direct cell cytotoxicity and antibody-mediated immune response. However, upon prolonged exposure to TME, the classical function of these so-called M1-type TAMs can be converted to another type, "M2-type," which are recruited by tumor cells so that they promote tumor growth and metastasis. This is the reason why the accumulation of TAMs in TME is correlated with poor prognosis in cancer patients. Both M1- and M2-types have high degree of plasticity, and M2-type cells can be reprogrammed to M1-type for therapeutic purposes. This characteristic introduces TAMs as promising target for developing novel cancer treatments. In addition, inhibition of M2-type cells and blocking their recruitment in TME, as well as their depletion by inducing apoptosis, are other approaches for effective immunotherapy of cancer. In this review, we summarize the potential of TAMs to be targeted for cancer immunotherapy and provide an up-to-date about novel strategies for targeting TAMs.

Modeling human gastric cancers in immunocompetent mice

Gastric cancer (GC) is a major cause of cancer-related mortality worldwide. GC is determined by multiple (epi)genetic and environmental factors; can occur at distinct anatomic positions of the stomach; and displays high heterogeneity, with different cellular origins and diverse histological and molecular features. This heterogeneity has hindered efforts to fully understand the pathology of GC and develop efficient therapeutics. In the past decade, great progress has been made in the study of GC, particularly in molecular subtyping, investigation of the immune microenvironment, and defining the evolutionary path and dynamics. Preclinical mouse models, particularly immunocompetent models that mimic the cellular and molecular features of human GC, in combination with organoid culture and clinical studies, have provided powerful tools for elucidating the molecular and cellular mechanisms underlying GC pathology and immune evasion, and the development of novel therapeutic strategies. Herein, we first briefly introduce current progress and challenges in GC study and subsequently summarize immunocompetent GC mouse models, emphasizing the potential application of genetically engineered mouse models in antitumor immunity and immunotherapy studies.

The viral etiology of EBV-associated gastric cancers contributes to their unique pathology, clinical outcomes, treatment responses and immune landscape

Epstein-Barr virus (EBV) is a pathogen known to cause a number of malignancies, often taking years for them to develop after primary infection. EBV-associated gastric cancer (EBVaGC) is one such malignancy, and is an immunologically, molecularly and pathologically distinct entity from EBV-negative gastric cancer (EBVnGC). In comparison with EBVnGCs, EBVaGCs overexpress a number of immune regulatory genes to help form an immunosuppressive tumor microenvironment (TME), have improved prognosis, and overall have an "immune-hot" phenotype. This review provides an overview of the histopathology, clinical features and clinical outcomes of EBVaGCs. We also summarize the differences between the TMEs of EBVaGCs and EBVnGCs, which includes significant differences in cell composition and immune infiltration. A list of available EBVaGC and EBVnGC gene expression datasets and computational tools are also provided within this review. Finally, an overview is provided of the various chemo- and immuno-therapeutics available in treating gastric cancers (GCs), with a focus on EBVaGCs.

Immunotherapeutic strategy in the management of gastric cancer: molecular profiles, current practice, and ongoing trials

Gastric cancer (GC) is the one of the most commonly solid cancer worldwide. Although under the aggressive treatment, the poor clinical outcomes of patients with GCs have not been improved. Current studies emphasized that targeting therapies or immune response-based therapeutic strategy may be a potential approach to improve the clinical outcomes. Moreover, accumulative evidence has reported the increasing expression of PD-L1 expression in GC cells and highlighted its role in the tumor progression. Currently, great development has been established in the immune checkpoint inhibitors (ICIs) and further changed the clinical practice of GC treatment and prognosis. In addition, the combination therapies with targeting therapy or traditional therapies are expected to push the development of immunotherapies. In our present review, we predominantly focus on the biomarkers and molecular profiles for immunotherapies in GCs and highlight the role and administration of ICIs-based immunotherapeutic strategies against the GCs.

Tumour-associated macrophages in gastric cancer: From function and mechanism to application

BACKGROUND

Gastric cancer (GC) is a malignant tumour, with high morbidity and mortality rates worldwide. The occurrence and development of GC is a complex process involving genetic changes in tumour cells and the influence of the surrounding tumour microenvironment (TME). Accumulative evidence shows that tumour-associated macrophages (TAMs) play a vital role in GC, acting as plentiful and active infiltrating inflammatory cells in the TME.

MAIN BODY

In this review, the different functions and mechanisms of TAMs in GC progression, including the conversion of phenotypic subtypes; promotion of tumour proliferation, invasion and migration; induction of chemoresistance; promotion of angiogenesis; modulation of immunosuppression; reprogramming of metabolism; and interaction with the microbial community are summarised. Although the role of TAMs in GC remains controversial in clinical settings, clarifying their significance in the treatment selection and prognostic prediction of GC could support optimising TAM-centred clinicaltherapy.

CONCLUSION

In summary, we reviewed the the phenotypic polarisation, function and molecular mechanism of TAMs and their potential applications in the treatment selection and prognostic prediction of GC.

Role of tumor-associated macrophages in common digestive system malignant tumors

Many digestive system malignant tumors are characterized by high incidence and mortality rate. Increasing evidence has revealed that the tumor microenvironment (TME) is involved in cancer initiation and tumor progression. Tumor-associated macrophages (TAMs) are a predominant constituent of the TME, and participate in the regulation of various biological behaviors and influence the prognosis of digestive system cancer. TAMs can be mainly classified into the antitumor M1 phenotype and protumor M2 phenotype. The latter especially are crucial drivers of tumor invasion, growth, angiogenesis, metastasis, immunosuppression, and resistance to therapy. TAMs are of importance in the occurrence, development, diagnosis, prognosis, and treatment of common digestive system malignant tumors. In this review, we summarize the role of TAMs in common digestive system malignant tumors, including esophageal, gastric, colorectal, pancreatic and liver cancers. How TAMs promote the development of tumors, and how they act as potential therapeutic targets and their clinical applications are also described.

Tumor microenvironment-mediated immune tolerance in development and treatment of gastric cancer

Tumor microenvironment is the general term for all non-cancer components and their metabolites in tumor tissue. These components include the extracellular matrix, fibroblasts, immune cells, and endothelial cells. In the early stages of tumors, the tumor microenvironment has a tumor suppressor function. As the tumor progresses, tumor immune tolerance is induced under the action of various factors, such that the tumor suppressor microenvironment is continuously transformed into a tumor-promoting microenvironment, which promotes tumor immune escape. Eventually, tumor cells manifest the characteristics of malignant proliferation, invasion, metastasis, and drug resistance. In recent years, stress effects of the extracellular matrix, metabolic and phenotypic changes of innate immune cells (such as neutrophils, mast cells), and adaptive immune cells in the tumor microenvironment have been revealed to mediate the emerging mechanisms of immune tolerance, providing us with a large number of emerging therapeutic targets to relieve tumor immune tolerance. Gastric cancer is one of the most common digestive tract malignancies worldwide, whose mortality rate remains high. According to latest guidelines, the first-line chemotherapy of advanced gastric cancer is the traditional platinum and fluorouracil therapy, while immunotherapy for gastric cancer is extremely limited, including only Human epidermal growth factor receptor 2 (HER-2) and programmed death ligand 1 (PD-L1) targeted drugs, whose benefits are limited. Clinical experiments confirmed that cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), vascular endothelial growth factor receptor (VEGFR) and other targeted drugs alone or in combination with other drugs have limited efficacy in patients with advanced gastric cancer, far less than in lung cancer, colon cancer, and other tumors. The failure of immunotherapy is mainly related to the induction of immune tolerance in the tumor microenvironment of gastric cancer. Therefore, solving the immune tolerance of tumors is key to the success of gastric cancer immunotherapy. In this study, we summarize the latest mechanisms of various components of the tumor microenvironment in gastric cancer for inducing immune tolerance and promoting the formation of the malignant phenotype of gastric cancer, as well as the research progress of targeting the tumor microenvironment to overcome immune tolerance in the treatment of gastric cancer.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Recent Progress and Future Perspectives of Immunotherapy in Advanced Gastric Cancer

As one of the most common forms of solid tumours, gastric carcinoma has been revealed as the third leading cause of death worldwide. The symptom of gastric cancer is usually not obvious and thus difficult to detect at earlier stages. Therefore, gastric cancer is already in the advanced stage once detected in patients, which has a poor prognosis due to ineffective therapies and multiple resistance. Recent advance in understanding the microenvironment of cancer has significantly promoted the development of immunotherapy for advanced gastric cancer. Immunotherapy can induce immune responses in gastric cancer patients thus leads to the destruction of cancer cells. In comparison of traditional therapy, immunotherapy has demonstrated robust efficacy and tolerable toxicity. Therefore, this novel strategy for treatment of advanced gastric cancer has gain increasingly popularity. In this review, we summarize recent progress of immunotherapy in advanced gastric cancer, such as immune check point inhibitors, adoptive cell therapy, VEGF inhibitors, cancer vaccines and CAR-T cell therapy. We highlight immunotherapies involved in clinical applications and discuss the existing challenges of current immunotherapies and promising strategies to overcome these limitations.

Immunotherapy as a Therapeutic Strategy for Gastrointestinal Cancer-Current Treatment Options and Future Perspectives

Gastrointestinal (GI) cancer constitutes a highly lethal entity among malignancies in the last decades and is still a major challenge for cancer therapeutic options. Despite the current combinational treatment strategies, including chemotherapy, surgery, radiotherapy, and targeted therapies, the survival rates remain notably low for patients with advanced disease. A better knowledge of the molecular mechanisms that influence tumor progression and the development of optimal therapeutic strategies for GI malignancies are urgently needed. Currently, the development and the assessment of the efficacy of immunotherapeutic agents in GI cancer are in the spotlight of several clinical trials. Thus, several new modalities and combinational treatments with other anti-neoplastic agents have been identified and evaluated for their efficiency in cancer management, including immune checkpoint inhibitors, adoptive cell transfer, chimeric antigen receptor (CAR)-T cell therapy, cancer vaccines, and/or combinations thereof. Understanding the interrelation among the tumor microenvironment, cancer progression, and immune resistance is pivotal for the optimal therapeutic management of all gastrointestinal solid tumors. This review will shed light on the recent advances and future directions of immunotherapy for malignant tumors of the GI system.