Genetically Modified T Cells for Esophageal Cancer Therapy: A Promising Clinical Application

A novel microenvironment regulated system CAR-T (MRS.CAR-T) for immunotherapeutic treatment of esophageal squamous carcinoma

Chimeric antigen receptor T cell immunotherapy has achieved promising therapeutic effects in the treatment of hematological malignancies. However, there are still many obstacles, including on-target off-tumor antigen expression, that prevent successful application to solid tumors. We designed a tumor microenvironment (TME) regulated system chimeric antigen receptor T (MRS.CAR-T) which can only be auto-activated in the solid TME. B7-H3 was selected as the target antigen for esophageal carcinoma. An element comprising a human serum albumin (HSA) binding peptide and a matrix metalloproteases (MMPs) cleavage site was inserted between the 5' terminal signal peptide and single chain fragment variable (scFv) of the CAR skeleton. Upon administration, HSA bound the binding peptide in MRS.B7-H3.CAR-T effectively and promoted proliferation and differentiation into memory cells. MRS.B7-H3.CAR-T was not cytotoxic in normal tissues expressing B7-H3 as the antigen recognition site in the scFv was cloaked by HSA. The anti-tumor function of MRS.B7-H3.CAR-T was recovered once the cleavage site was cleaved by MMPs in the TME. The anti-tumor efficacy associated with MRS.B7-H3.CAR-T cells was improved compared to classic B7-H3.CAR-T cells in vitro and less IFN-γ was released, suggesting a treatment that may induce less extent of cytokine release syndrome-mediated toxicity. In vivo, MRS.B7-H3.CAR-T cells had strong anti-tumor activity and were safe. MRS.CAR-T represents a novel strategy to improve the efficacy and safety of CAR-T therapy in solid tumors.

Clinical application and prospect of immune checkpoint inhibitors for CAR-NK cell in tumor immunotherapy

Chimeric antigen receptor (CAR) engineering of natural killer (NK) cells is an attractive research field in tumor immunotherapy. While CAR is genetically engineered to express certain molecules, it retains the intrinsic ability to recognize tumor cells through its own receptors. Additionally, NK cells do not depend on T cell receptors for cytotoxic killing. CAR-NK cells exhibit some differences to CAR-T cells in terms of more precise killing, numerous cell sources, and increased effectiveness in solid tumors. However, some problems still exist with CAR-NK cell therapy, such as cytotoxicity, low transfection efficiency, and storage issues. Immune checkpoints inhibit immune cells from performing their normal killing function, and the clinical application of immune checkpoint inhibitors for cancer treatment has become a key therapeutic strategy. The application of CAR-T cells and immune checkpoint inhibitors is being evaluated in numerous ongoing basic research and clinical studies. Immune checkpoints may affect the function of CAR-NK cell therapy. In this review, we describe the combination of existing CAR-NK cell technology with immune checkpoint therapy and discuss the research of CAR-NK cell technology and future clinical treatments. We also summarize the progress of clinical trials of CAR-NK cells and immune checkpoint therapy.

Immune-based combination therapy for esophageal cancer

Esophageal cancer (EC) is an aggressive malignancy raising a healthcare concern worldwide. Standard treatment options include surgical resection, chemotherapy, radiation therapy, and targeted molecular therapy. The five-year survival rate for all stages of EC is approximately 20%, ranging from 5% to 47%, with a high recurrence rate and poor prognosis after treatment. Immunotherapy has shown better efficacy and tolerance than conventional therapies for several malignancies. Immunotherapy of EC, including immune checkpoint inhibitors, cancer vaccines, and adoptive cell therapy, has shown clinical advantages. In particular, monoclonal antibodies against PD-1 have a satisfactory role in combination therapy and are recommended for first- or second-line treatments. Here, we present a systematic summary and analysis of immunotherapy-based combination therapies for EC.

Global research trend of esophageal squamous cell carcinoma from 2012 to 2022: a bibliometric analysis

Background

Esophageal cancer is currently a worldwide health problem. Esophageal squamous cell carcinoma (ESCC) is the most common pathological type of esophageal cancer, and its treatment methods and therapeutic effects are relatively limited, so it also requires the unremitting efforts of basic and clinical researchers to overcome difficulties. Bibliometric analysis can help sort out global research trends and hotspots, but no bibliometric analysis of ESCC has been reported. Therefore, we performed this study to analyze the global trends and potential hotspots of ESCC to indicate future research directions.

Methods

The articles related to ESCC research were collected from the WoS Core Collection SCI-EXPANDED database from 2012 to 2022. The article information was analyzed by BiblioShiny and VOSviewer. Results were presented as bar and network visualization to describe the current trend of ESCC research. This was a retrospective study evaluating data that is publicly available online and at libraries and institutional review board approval, as such, was not demanded.

Results

The global publication trend illustrated a strong growth in the ESCC research field (annual growth rate of 11.4%) and the citation trend increased from an average of 2.98 citations per article per year in 2012 to an average of 3.84 citations per article per year in 2019. With the corresponding author’s country, China contributed the largest number (5,063 articles). The scholars from China and USA had the most collaboration (427 times). China had the largest number of institutions conducting ESCC research. Oncotarget, Oncology Letters, and Annals of Surgical Oncology published the most articles, while Cancer Research, International Journal of Cancer, and Journal of Clinical Oncology had the most local citations. Furthermore, the clinical research hotspots involved in the treatment of ESCC and the basic research hotspots involved in tumor malignant phenotype have received the most attention in recent years.

Conclusion

Our study demonstrated that the research of ESCC has developed rapidly in recent years, and the academic institutions in China have played a decisive role in this field. The global research purpose is to find effective therapies against ESCC, so some emerging hotspots related to ESCC treatment, such as endoscopic therapy, chemoradiotherapy, immunotherapy, tumor microenvironment, and the epithelial-mesenchymal transition will receive more attention and develop rapidly in the future.

Chimeric Antigen Receptor (CAR)-T Cell Immunotherapy Against Thoracic Malignancies: Challenges and Opportunities

Different from surgery, chemical therapy, radio-therapy and target therapy, Chimeric antigen receptor-modified T (CAR-T) cells, a novel adoptive immunotherapy strategy, have been used successfully against both hematological tumors and solid tumors. Although several problems have reduced engineered CAR-T cell therapeutic outcomes in clinical trials for the treatment of thoracic malignancies, including the lack of specific antigens, an immunosuppressive tumor microenvironment, a low level of CAR-T cell infiltration into tumor tissues, off-target toxicity, and other safety issues, CAR-T cell treatment is still full of bright future. In this review, we outline the basic structure and characteristics of CAR-T cells among different period, summarize the common tumor-associated antigens in clinical trials of CAR-T cell therapy for thoracic malignancies, and point out the current challenges and new strategies, aiming to provide new ideas and approaches for preclinical experiments and clinical trials of CAR-T cell therapy for thoracic malignancies.