CD38-Expressing Myeloid-Derived Suppressor Cells Promote Tumor Growth in a Murine Model of Esophageal Cancer

Autoimmune Diseases and Plasma Cells Dyscrasias: Pathogenetic, Molecular and Prognostic Correlations

Multiple myeloma and monoclonal gammopathy of undetermined significance are plasma cell dyscrasias characterized by monoclonal proliferation of pathological plasma cells with uncontrolled production of immunoglobulins. Autoimmune pathologies are conditions in which T and B lymphocytes develop a tendency to activate towards self-antigens in the absence of exogenous triggers. The aim of our review is to show the possible correlations between the two pathological aspects. Molecular studies have shown how different cytokines that either cause inflammation or control the immune system play a part in the growth of immunotolerance conditions that make it easier for the development of neoplastic malignancies. Uncontrolled immune activation resulting in chronic inflammation is also known to be at the basis of the evolution toward neoplastic pathologies, as well as multiple myeloma. Another point is the impact that myeloma-specific therapies have on the course of concomitant autoimmune diseases. Indeed, cases have been observed of patients suffering from multiple myeloma treated with daratumumab and bortezomib who also benefited from their autoimmune condition or patients under treatment with immunomodulators in which there has been an arising or worsening of autoimmunity conditions. The role of bone marrow transplantation in the course of concomitant autoimmune diseases remains under analysis.

Chemokines and Their Receptors: Predictors of Therapeutic Potential in Tumor Microenvironment on Esophageal Cancer

Esophageal carcinoma (ESCA) is an aggressive solid tumor. The 5-year survival rate for patients with ESCA is estimated to be less than 20%, mainly due to tumor invasion and metastasis. Therefore, it is urgent to improve early diagnostic tools and effective treatments for ESCA patients. Tumor microenvironment (TME) enhances the ability of tumor cells to proliferate, migrate, and escape from the immune system, thus promoting the occurrence and development of tumor. TME contains chemokines. Chemokines consist of four major families, which are mainly composed of CC and CXC families. The main purpose of this review is to understand the CC and CXC chemokines and their receptors in ESCA, to improve the understanding of tumorigenesis of ESCA and determine new biomarkers for the diagnosis and prognosis of ESCA. We reviewed the literature on CC and CXC chemokines and their receptors in ESCA identified by PubMed database. This article introduces the general structures and functions of CC, CXC chemokines and their receptors in TME, as well as their roles in the progress of ESCA. Chemokines are involved in the development of ESCA, such as cancer cell invasion, metastasis, angiogenesis, and radioresistance, and are key determinants of disease progression, which have a great impact on patient prognosis and treatment response. In addition, a full understanding of their mechanism of action is essential to further verify that these chemokines and their receptors may serve as biomarkers or therapeutic targets of ESCA.

Mechanisms of tumor immunosuppressive microenvironment formation in esophageal cancer

As a highly invasive malignancy, esophageal cancer (EC) is a global health issue, and was the eighth most prevalent cancer and the sixth leading cause of cancer-related death worldwide in 2020. Due to its highly immunogenic nature, emer-ging immunotherapy approaches, such as immune checkpoint blockade, have demonstrated promising efficacy in treating EC; however, certain limitations and challenges still exist. In addition, tumors may exhibit primary or acquired resistance to immunotherapy in the tumor immune microenvironment (TIME); thus, understanding the TIME is urgent and crucial, especially given the im-portance of an immunosuppressive microenvironment in tumor progression. The aim of this review was to better elucidate the mechanisms of the suppressive TIME, including cell infiltration, immune cell subsets, cytokines and signaling pathways in the tumor microenvironment of EC patients, as well as the downregulated expression of major histocompatibility complex molecules in tumor cells, to obtain a better understanding of the differences in EC patient responses to immunotherapeutic strategies and accurately predict the efficacy of immunotherapies. Therefore, personalized treatments could be developed to maximize the advantages of immunotherapy.

Association between periodontitis and inflammatory comorbidities: The common role of innate immune cells, underlying mechanisms and therapeutic targets

Periodontitis, which is related to various systemic diseases, is a chronic inflammatory disease caused by periodontal dysbiosis of the microbiota. Multiple factors can influence the interaction of periodontitis and associated inflammatory disorders, among which host immunity is an important contributor to this interaction. Innate immunity can be activated aberrantly because of the systemic inflammation induced by periodontitis. This aberrant activation not only exacerbates periodontal tissue damage but also impairs systemic health, triggering or aggravating inflammatory comorbidities. Therefore, innate immunity is a potential therapeutic target for periodontitis and associated inflammatory comorbidities. This review delineates analogous aberrations of innate immune cells in periodontitis and comorbid conditions such as atherosclerosis, diabetes, obesity, and rheumatoid arthritis. The mechanisms behind these changes in innate immune cells are discussed, including trained immunity and clonal hematopoiesis of indeterminate potential (CHIP), which can mediate the abnormal activation and myeloid-biased differentiation of hematopoietic stem and progenitor cells. Besides, the expansion of myeloid-derived suppressor cells (MDSCs), which have immunosuppressive and osteolytic effects on peripheral tissues, also contributes to the interaction between periodontitis and its inflammatory comorbidities. The potential treatment targets for relieving the risk of both periodontitis and systemic conditions are also elucidated, such as the modulation of innate immunity cells and mediators, the regulation of trained immunity and CHIP, as well as the inhibition of MDSCs' expansion.

FABP6 serves as a new therapeutic target in esophageal tumor

BACKGROUND

Esophageal cancer is one of the most common malignant tumors with high incidence and mortality rates. Despite the continuous development of treatment options, the prognosis for esophageal cancer patients remains poor. Therefore, there is an urgent need for new diagnostic and therapeutic targets in clinical practice to improve the survival of patients with esophageal cancer.

METHODS

In this study, we conducted a comprehensive scRNA-seq analysis of the tumor microenvironment in primary esophageal tumors to elucidate cell composition and heterogeneity. Using Seurat, we identified eight clusters, encompassing non-immune cells (fibroblasts, myofibroblasts, endothelial cells, and epithelial cells) and immunocytes (myeloid-derived cells, T cells, B cells, and plasma cells). Compared to normal tissues, tumors exhibited an increased proportion of epithelial cells and alterations in immune cell infiltration. Analysis of epithelial cells revealed a cluster (cluster 0) with a high differentiation score and early distribution, suggesting its importance as a precursor cell.

RESULTS

Cluster 0 was characterized by high expression of FABP6, indicating a potential role in fatty acid metabolism and tumor growth. T cell analysis revealed shifts in the balance between Treg and CD8+ effector T cells in tumor tissues. Cellular communication analysis identified increased interactions between FABP6+ tumor cells and T cells, with the involvement of the MIF-related pathway and the CD74-CD44 interaction. This study provides insights into the cellular landscape and immune interactions within esophageal tumors, contributing to a better understanding of tumor heterogeneity and potential therapeutic targets.

The Role of Neutrophil in COVID-19: Positive or Negative

BACKGROUND

Neutrophils are the first line of defense against pathogens. They are divided into multiple subpopulations during development and kill pathogens through various mechanisms. Neutrophils are considered one of the markers of severe COVID-19.

SUMMARY

In-depth research has revealed that neutrophil subpopulations have multiple complex functions. Different subsets of neutrophils play an important role in the progression of COVID-19.

KEY MESSAGES

In this review, we provide a detailed overview of the developmental processes of neutrophils at different stages and their recruitment and activation after SARS-CoV-2 infection, aiming to elucidate the changes in neutrophil subpopulations, characteristics, and functions after infection and provide a reference for mechanistic research on neutrophil subpopulations in the context of SARS-CoV-2 infection. In addition, we have also summarized research progress on potential targeted drugs for neutrophil immunotherapy, hoping to provide information that aids the development of therapeutic drugs for the clinical treatment of critically ill COVID-19 patients.

Effective Reprogramming of Patient-Derived M2-Polarized Glioblastoma-Associated Microglia/Macrophages by Treatment with GW2580

PURPOSE

Targeting immunosuppressive and pro-tumorigenic glioblastoma (GBM)-associated macrophages and microglial cells (GAM) has great potential to improve patient outcomes. Colony-stimulating factor-1 receptor (CSF1R) has emerged as a promising target for reprograming anti-inflammatory M2-like GAMs. However, treatment data on patient-derived, tumor-educated GAMs and their influence on the adaptive immunity are lacking.

EXPERIMENTAL DESIGN

CD11b+-GAMs freshly isolated from patient tumors were treated with CSF1R-targeting drugs PLX3397, BLZ945, and GW2580. Phenotypical changes upon treatment were assessed using RNA sequencing, flow cytometry, and cytokine quantification. Functional analyses included inducible nitric oxide synthase activity, phagocytosis, transmigration, and autologous tumor cell killing assays. Antitumor effects and changes in GAM activation were confirmed in a complex patient-derived 3D tumor organoid model serving as a tumor avatar.

RESULTS

The most effective reprogramming of GAMs was observed upon GW2580 treatment, which led to the downregulation of M2-related markers, IL6, IL10, ERK1/2, and MAPK signaling pathways, while M1-like markers, gene set enrichment indicating activated MHC-II presentation, phagocytosis, and T-cell killing were substantially increased. Moreover, treatment of patient-derived GBM organoids with GW2580 confirmed successful reprogramming, resulting in impaired tumor cell proliferation. In line with its failure in clinical trials, PLX3397 was ineffective in our analysis.

CONCLUSIONS

This comparative analysis of CSF1R-targeting drugs on patient-derived GAMs and human GBM avatars identified GW2580 as the most powerful inhibitor with the ability to polarize immunosuppressive GAMs to a proinflammatory phenotype, supporting antitumor T-cell responses while also exerting a direct antitumor effect. These data indicate that GW2580 could be an important pillar in future therapies for GBM.

Tumour-derived exosomes promote the induction of monocytic myeloid-derived suppressor cells from peripheral blood mononuclear cells by delivering miR-106a-5p and miR-146a-5p in multiple myeloma

The shift of the tumour immune microenvironment to a suppressive state promotes not only the development and progression of the disease in multiple myeloma (MM) but also the development of resistance to immunotherapy. We previously demonstrated that myeloma cells can induce monocytic myeloid-derived suppressor cells (M-MDSCs) from healthy peripheral blood mononuclear cells (PBMCs) via the concomitant secretion of CC motif chemokine ligand 5 (CCL5) and macrophage migration inhibitory factor (MIF), but an unknown mediator also promotes M-MDSC induction. This study demonstrates that miR-106a-5p and miR-146a-5p delivered by tumour-derived exosomes (TEXs) from myeloma cells play essential roles in M-MDSC induction in MM. MiR-106a-5p and miR-146a-5p upregulate various immunosuppressive/inflammatory molecules in PBMCs, such as IDO1, CD38, programmed death-ligand 1, CCL5 or MYD88, which are involved in interferon (IFN)-α response, IFN-γ response, inflammatory response, tumour necrosis factor-α signalling and Interleukin-6-JAK-STAT3 signalling. These molecular features mirror the increases in myeloid cellular compartments of PBMCs when co-cultured with myeloma cells. MiR-106a-5p and miR-146a-5p have a compensatory relationship, and these two miRNAs collaborate with CCL5 and MIF to promote M-MDSC induction. Collectively, novel therapeutic candidates may be involved in TEX-mediated sequential cellular and molecular events underlying M-MDSC induction, potentially improving the efficacy of immunotherapy.

A myeloid program associated with COVID-19 severity is decreased by therapeutic blockade of IL-6 signaling

Altered myeloid inflammation and lymphopenia are hallmarks of severe infections. We identified the upregulated EN-RAGE gene program in airway and blood myeloid cells from patients with acute lung injury from SARS-CoV-2 or other causes across 7 cohorts. This program was associated with greater clinical severity and predicted future mechanical ventilation and death. EN-RAGEhi myeloid cells express features consistent with suppressor cell functionality, including low HLA-DR and high PD-L1. Sustained EN-RAGE program expression in airway and blood myeloid cells correlated with clinical severity and increasing expression of T cell dysfunction markers. IL-6 upregulated many EN-RAGE program genes in monocytes in vitro. IL-6 signaling blockade by tocilizumab in a placebo-controlled clinical trial led to rapid normalization of EN-RAGE and T cell gene expression. This identifies IL-6 as a key driver of myeloid dysregulation associated with worse clinical outcomes in COVID-19 patients and provides insights into shared pathophysiological mechanisms in non-COVID-19 ARDS.

Cancer cell-intrinsic mechanisms driving acquired immune tolerance

Immune evasion is a hallmark of cancer, enabling tumors to survive contact with the host immune system and evade the cycle of immune recognition and destruction. Here, we review the current understanding of the cancer cell-intrinsic factors driving immune evasion. We focus on T cells as key effectors of anti-cancer immunity and argue that cancer cells evade immune destruction by gaining control over pathways that usually serve to maintain physiological tolerance to self. Using this framework, we place recent mechanistic advances in the understanding of cancer immune evasion into broad categories of control over T cell localization, antigen recognition, and acquisition of optimal effector function. We discuss the redundancy in the pathways involved and identify knowledge gaps that must be overcome to better target immune evasion, including the need for better, routinely available tools that incorporate the growing understanding of evasion mechanisms to stratify patients for therapy and trials.

CD38 as a pan-hematologic target for chimeric antigen receptor T cells

Many hematologic malignancies are not curable with chemotherapy and require novel therapeutic approaches. Chimeric antigen receptor (CAR) T-cell therapy is 1 such approach that involves the transfer of T cells engineered to express CARs for a specific cell-surface antigen. CD38 is a validated tumor antigen in multiple myeloma (MM) and T-cell acute lymphoblastic leukemia (T-ALL) and is also overexpressed in acute myeloid leukemia (AML). Here, we developed human CD38-redirected T cells (CART-38) as a unified approach to treat 3 different hematologic malignancies that occur across the pediatric-to-adult age spectrum. Importantly, CD38 expression on activated T cells did not impair CART-38 cells expansion or in vitro function. In xenografted mice, CART-38 mediated the rejection of AML, T-ALL, and MM cell lines and primary samples and prolonged survival. In a xenograft model of normal human hematopoiesis, CART-38 resulted in the expected reduction of hematopoietic progenitors, which warrants caution and careful monitoring of this potential toxicity when translating this new immunotherapy into the clinic. Deploying CART-38 against multiple CD38-expressing malignancies is significant because it expands the potential for this novel therapy to affect diverse patient populations.

Oncogenic Ras and ΔNp63α cooperate to recruit immunosuppressive polymorphonuclear myeloid-derived suppressor cells in a mouse model of squamous cancer pathogenesis

Introduction

Amplification of human chromosome 3q26-29, which encodes oncoprotein ΔNp63 among other isoforms of the p63 family, is a feature common to squamous cell carcinomas (SCCs) of multiple tissue origins. Along with overexpression of ΔNp63, activation of the protooncogene, RAS, whether by overexpression or oncogenic mutation, is frequently observed in many cancers. In this study, analysis of transcriptome data from The Cancer Genome Atlas (TCGA) demonstrated that expression of TP63 mRNA, particularly ΔNp63 isoforms, and HRAS are significantly elevated in advanced squamous cell carcinomas of the head and neck (HNSCCs), suggesting pathological significance. However, how co-overexpressed ΔNp63 and HRAS affect the immunosuppressive tumor microenvironment (TME) is incompletely understood.

Methods

Here, we established and characterized an immune competent mouse model using primary keratinocytes with retroviral-mediated overexpression of ΔNp63α and constitutively activated HRAS (v-rasHa G12R) to evaluate the role of these oncogenes in the immune TME.

Results

In this model, orthotopic grafting of wildtype syngeneic keratinocytes expressing both v-rasHa and elevated levels of ΔNp63α consistently yield carcinomas in syngeneic hosts, while cells expressing v-rasHa alone yield predominantly papillomas. We found that polymorphonuclear (PMN) myeloid cells, experimentally validated to be immunosuppressive and thus representing myeloid-derived suppressor cells (PMN-MDSCs), were significantly recruited into the TME of carcinomas arising early following orthotopic grafting of ΔNp63α/v-rasHa-expressing keratinocytes. ΔNp63α/v-rasHa-driven carcinomas expressed higher levels of chemokines implicated in recruitment of MDSCs compared to v-rasHa-initiated tumors, providing a heretofore undescribed link between ΔNp63α/HRAS-driven carcinomas and the development of an immunosuppressive TME.

Conclusion

These results support the utilization of a genetic carcinogenesis model harboring specific genomic drivers of malignancy to study mechanisms underlying the development of local immunosuppression.

The interplay between the DNA damage response and ectonucleotidases modulates tumor response to therapy

The extracellular nucleoside adenosine reduces tissue inflammation and is generated by irreversible dephosphorylation of adenosine monophosphate (AMP) mediated by the ectonucleotidase CD73. The pro-inflammatory nucleotides adenosine triphosphate, nicotinamide adenine dinucleotide, and cyclic guanosine -monophosphate-AMP (cGAMP), which are produced in the tumor microenvironment (TME) during therapy-induced immunogenic cell death and activation of innate immune signaling, can be converted into AMP by ectonucleotidases CD39, CD38, and CD203a/ENPP1. Thus, ectonucleotidases shape the TME by converting immune-activating signals into an immunosuppressive one. Ectonucleotidases also hinder the ability of therapies including radiation therapy, which enhance the release of pro-inflammatory nucleotides in the extracellular milieu, to induce immune-mediated tumor rejection. Here, we review the immunosuppressive effects of adenosine and the role of different ectonucleotidases in modulating antitumor immune responses. We discuss emerging opportunities to target adenosine generation and/or its ability to signal via adenosine receptors expressed by immune and cancer cells in the context of combination immunotherapy and radiotherapy.

Establishment and Characterization of Free-Floating 3D Macrophage Programming Model in the Presence of Cancer Cell Spheroids

Reprogramming of tumor-associated macrophages (TAMs) is a promising strategy for cancer immunotherapy. Several studies have shown that cancer cells induce/support the formation of immunosuppressive TAMs phenotypes. However, the specific factors that orchestrate this immunosuppressive process are unknown or poorly studied. In vivo studies are expensive, complex, and ethically constrained. Therefore, 3D cell interaction models could become a unique framework for the identification of important TAMs programming factors. In this study, we have established and characterized a new in vitro 3D model for macrophage programming in the presence of cancer cell spheroids. First, it was demonstrated that the profile of cytokines, chemokines, and surface markers of 3D-cultured macrophages did not differ conceptually from monolayer-cultured M1 and M2-programmed macrophages. Second, the possibility of reprogramming macrophages in 3D conditions was investigated. In total, the dynamic changes in 6 surface markers, 11 cytokines, and 22 chemokines were analyzed upon macrophage programming (M1 and M2) and reprogramming (M1→M2 and M2→M1). According to the findings, the reprogramming resulted in a mixed macrophage phenotype that expressed both immunosuppressive and anti-cancer immunostimulatory features. Third, cancer cell spheroids were shown to stimulate the production of immunosuppressive M2 markers as well as pro-tumor cytokines and chemokines. In summary, the newly developed 3D model of cancer cell spheroid/macrophage co-culture under free-floating conditions can be used for studies on macrophage plasticity and for the development of targeted cancer immunotherapy.

Mechanisms of esophageal cancer metastasis and treatment progress

Esophageal cancer is a prevalent tumor of the digestive tract worldwide. The detection rate of early-stage esophageal cancer is very low, and most patients are diagnosed with metastasis. Metastasis of esophageal cancer mainly includes direct diffusion metastasis, hematogenous metastasis, and lymphatic metastasis. This article reviews the metabolic process of esophageal cancer metastasis and the mechanisms by which M2 macrophages, CAF, regulatory T cells, and their released cytokines, including chemokines, interleukins, and growth factors, form an immune barrier to the anti-tumor immune response mediated by CD8+ T cells, impeding their ability to kill tumor cells during tumor immune escape. The effect of Ferroptosis on the metastasis of esophageal cancer is briefly mentioned. Moreover, the paper also summarizes common drugs and research directions in chemotherapy, immunotherapy, and targeted therapy for advanced metastatic esophageal cancer. This review aims to serve as a foundation for further investigations into the mechanism and management of esophageal cancer metastasis.

Identification of a unique intervillous cellular signature in chronic histiocytic intervillositis

INTRODUCTION

Chronic histiocytic intervillositis (CHI) is a rare histopathological lesion in the placenta characterized by an infiltrate of CD68⁺ cells in the intervillous space. CHI is associated with adverse pregnancy outcomes such as miscarriage, fetal growth restriction, and (late) intrauterine fetal death. The adverse pregnancy outcomes and a variable recurrence rate of 25-100% underline its clinical relevance. The pathophysiologic mechanism of CHI is unclear, but it appears to be immunologically driven. The aim of this study was to obtain a better understanding of the phenotype of the cellular infiltrate in CHI.

METHOD

We used imaging mass cytometry to achieve in-depth visualization of the intervillous maternal immune cells and investigated their spatial orientation in situ in relation to the fetal syncytiotrophoblast.

RESULTS

We found three phenotypically distinct CD68⁺HLA-DR⁺CD38⁺ cell clusters that were unique for CHI. Additionally, syncytiotrophoblast cells in the vicinity of these CD68⁺HLA-DR⁺CD38⁺ cells showed decreased expression of the immunosuppressive enzyme CD39.

DISCUSSION

The current results provide novel insight into the phenotype of CD68⁺ cells in CHI. The identification of unique CD68⁺ cell clusters will allow more detailed analysis of their function and could result in novel therapeutic targets for CHI.

Cell-Intrinsic CD38 Expression Sustains Exhausted CD8+ T Cells by Regulating Their Survival and Metabolism during Chronic Viral Infection

Acute and chronic viral infections result in the differentiation of effector and exhausted T cells with functional and phenotypic differences that dictate whether the infection is cleared or progresses to chronicity. High CD38 expression has been observed on CD8+ T cells across various viral infections and tumors in patients, suggesting an important regulatory function for CD38 on responding T cells. Here, we show that CD38 expression was increased and sustained on exhausted CD8+ T cells following chronic lymphocytic choriomeningitis virus (LCMV) infection, with lower levels observed on T cells from acute LCMV infection. We uncovered a cell-intrinsic role for CD38 expression in regulating the survival of effector and exhausted CD8+ T cells. We observed increased proliferation and function of Cd38-/- CD8+ progenitor exhausted T cells compared to those of wild-type (WT) cells. Furthermore, decreased oxidative phosphorylation and glycolytic potential were observed in Cd38-/- CD8+ T cells during chronic but not acute LCMV infection. Our studies reveal that CD38 has a dual cell-intrinsic function in CD8+ T cells, where it decreases proliferation and function yet supports their survival and metabolism. These findings show that CD38 is not only a marker of T cell activation but also has regulatory functions on effector and exhausted CD8+ T cells. IMPORTANCE Our study shows how CD38 expression is regulated on CD8+ T cells responding during acute and chronic viral infection. We observed higher CD38 levels on CD8+ T cells during chronic viral infection compared to levels during acute viral infection. Deleting CD38 had an important cell-intrinsic function in ensuring the survival of virus-specific CD8+ T cells throughout the course of viral infection. We found defective metabolism in Cd38-/- CD8+ T cells arising during chronic infection and changes in their progenitor T cell phenotype. Our studies revealed a dual cell-intrinsic role for CD38 in limiting proliferation and granzyme B production in virus-specific exhausted T cells while also promoting their survival. These data highlight new avenues for research into the mechanisms through which CD38 regulates the survival and metabolism of CD8+ T cell responses to viral infections.

Improving outcomes in patients with oesophageal cancer

The care of patients with oesophageal cancer or of individuals who have an elevated risk of oesophageal cancer has changed dramatically. The epidemiology of squamous cell and adenocarcinoma of the oesophagus has diverged over the past several decades, with a marked increase in incidence only for oesophageal adenocarcinoma. Only in the past decade, however, have molecular features that distinguish these two forms of the disease been identified. This advance has the potential to improve screening for oesophageal cancers through the development of novel minimally invasive diagnostic technologies predicated on cancer-specific genomic or epigenetic alterations. Surgical techniques have also evolved towards less invasive approaches associated with less morbidity, without compromising oncological outcomes. With improvements in multidisciplinary care, advances in radiotherapy and new tools to detect minimal residual disease, certain patients may no longer even require surgical tumour resection. However, perhaps the most anticipated advance in the treatment of patients with oesophageal cancer is the advent of immune-checkpoint inhibitors, which harness and enhance the host immune response against cancer. In this Review, we discuss all these advances in the management of oesophageal cancer, representing only the beginning of a transformation in our quest to improve patient outcomes.

Unleashing the potential of combining FGFR inhibitor and immune checkpoint blockade for FGF/FGFR signaling in tumor microenvironment

BACKGROUND

Fibroblast growth factors (FGFs) and their receptors (FGFRs) play a crucial role in cell fate and angiogenesis, with dysregulation of the signaling axis driving tumorigenesis. Therefore, many studies have targeted FGF/FGFR signaling for cancer therapy and several FGFR inhibitors have promising results in different tumors but treatment efficiency may still be improved. The clinical use of immune checkpoint blockade (ICB) has resulted in sustained remission for patients. MAIN: Although there is limited data linking FGFR inhibitors and immunotherapy, preclinical research suggest that FGF/FGFR signaling is involved in regulating the tumor microenvironment (TME) including immune cells, vasculogenesis, and epithelial-mesenchymal transition (EMT). This raises the possibility that ICB in combination with FGFR-tyrosine kinase inhibitors (FGFR-TKIs) may be feasible for treatment option for patients with dysregulated FGF/FGFR signaling.

CONCLUSION

Here, we review the role of FGF/FGFR signaling in TME regulation and the potential mechanisms of FGFR-TKI in combination with ICB. In addition, we review clinical data surrounding ICB alone or in combination with FGFR-TKI for the treatment of FGFR-dysregulated tumors, highlighting that FGFR inhibitors may sensitize the response to ICB by impacting various stages of the "cancer-immune cycle".

PES1 reduces CD8+ T cell infiltration and immunotherapy sensitivity via interrupting ILF3-IL15 complex in esophageal squamous cell carcinoma

BACKGROUND

Although immune checkpoint blockade (ICB) therapy has brought survival benefits to patients with specific cancer types, most of cancer patients remain refractory to the ICB therapy, which is largely attributed to the immunosuppressive tumor microenvironment. Thereby, it is urgent to profile key molecules and signal pathways responsible for modification of tumor microenvironment.

METHODS

Multiple databases of esophageal squamous cell carcinoma (ESCC) were integratively analyzed to screen candidate genes responsible for infiltration of CD8⁺ T cells. Expression of pescadillo ribosomal biogenesis factor 1 (PES1) in clinical ESCC samples was examined by qRT-PCR, western blotting, and immunohistochemistry. The mechanisms of PES1 were investigated via RNA sequencing and mass spectrometry followed by immunoprecipitation and proximity ligation assay. The clinical and therapeutic significance of PES1 in ESCC was comprehensively investigated using ESCC cells and mouse model.

RESULTS

PES1 was significantly upregulated and correlated with poor prognosis in ESCC patients. PES1 knockdown decreased ESCC cell growth in vitro and in vivo and enhanced the efficacy of ICB therapy in mouse model, which was established through subcutaneous inoculation with ESCC cells. Analyses on RNA sequencing and mass spectrometry suggested that PES1 expression was negatively correlated with IL15 and ILF3 was one of the PES1-associated proteins. It has been known that ILF3 interacts with and stabilizes IL15 mRNA to increase IL15 protein level. Our data further indicated that PES1 interfered with the interaction between ILF3 and IL15 mRNA and impaired ILF3-mediated stabilization of IL15 mRNA, which eventually reduced the protein level of IL15. Interestingly, the inhibitory effect of ICB therapy boosted by PES1 knockdown dramatically antagonized by knockdown of IL15, which suppressed the tumor-infiltrated CD8⁺ T cells in ESCC. Finally, we confirmed the relationships among PES1, IL15, and CD8⁺ T cell infiltration in 10 locally advanced ESCC patients receiving ICB neoadjuvant therapy and demonstrated that ICB therapy would be more effective in those with low expression of PES1.

CONCLUSIONS

Altogether, our findings herein provided novel insights on biological function and clinical significance of PES1 and suggested that high expression of PES1 could suppress ILF3-IL15 axis-mediated immunosurveillance and promote resistance to ICB through restraining tumor-infiltrated CD8⁺ T cells.

Lnc-17Rik promotes the immunosuppressive function of Myeloid-Derived suppressive cells in esophageal cancer

Myeloid-derived suppressor cells (MDSCs) are a population of immature bone marrow cells that accumulate in large numbers in the spleen, peripheral blood, bone marrow, lymph nodes, and local and metastatic foci of tumors. C/EBP homologous protein (CHOP) and CCAAT/enhancer binding protein β (C/EBPβ) play key roles in regulating the immunosuppressive function and differentiation of MDSCs. Our study revealed that the long noncoding RNA Lnc-17Rik was able to promote immunosuppression in tumors by facilitating the activation and expression of key genes involved in MDSC differentiation. Lnc-17Rik was shown to directly interact with CHOP and C/EBPβ LIP to facilitate their dissociation from the transcriptional repressor complex involving C/EBP LAP/LIP/CHOP. Moreover, Lnc-17Rik increased the association of WD repeat-containing protein 5 (WDR5) with C/EBP LAP, promoting H3K4me3 enrichment in the promoter regions of arginase 1 (Arg-1), cyclooxygenase 2 (COX2), nitric oxide synthase 2 (NOS2) and NADPH oxidase 2 (NOX2) to enhance the expression of these genes. Furthermore, using a CD45 chimeric model we confirmed that Lnc-17Rik promoted the differentiation of monocytic (M)-MDSCs in vivo with the introduction of Lnc-17Rik-overexpressing MDSCs shown to promote tumor growth as a result of enhancing their immunosuppressive function. Notably, human Lnc-17Rik is highly homologous to mouse Lnc-17Rik and fulfills similar functions in human MDSC-like cells. In addition, we also found a high level of Lnc-17Rik in peripheral blood MDSC of patients with esophageal cancer. These findings suggest that Lnc-17Rik plays an important role in controlling the immunosuppressive function of MDSCs in the tumor environment and may further serve as a potential therapeutic target for patients with esophageal cancer.

Evolving roles of CD38 metabolism in solid tumour microenvironment

Given that plenty of clinical findings and reviews have already explained in detail on the progression of CD38 in multiple myeloma and haematological system tumours, here we no longer give unnecessary discussion on the above progression. Though therapeutic antibodies have been regarded as a greatest breakthrough in multiple myeloma immunotherapies due to the durable anti-tumour responses in the clinic, but the role of CD38 in the immunologic regulation and evasion of non-hematopoietic solid tumours are just initiated and controversial. Therefore, we will focus on the bio-function of CD38 enzymatic substrates or metabolites in the variety of non-hematopoietic malignancies and the potential therapeutic value of targeting the CD38-NAD+ or CD38-cADPR/ADPR signal axis. Though limited, we review some ongoing researches and clinical trials on therapeutic approaches in solid tumour as well.

Daratumumab induces cell-mediated cytotoxicity of primary effusion lymphoma and is active against refractory disease

Primary effusion lymphoma (PEL), an aggressive non-Hodgkin lymphoma caused by Kaposi sarcoma-associated herpesvirus (KSHV), lacks standard therapy and has a median survival of 10-22 months with combination chemotherapy. PEL is a tumor of plasmablast-like B cells generally expressing CD38, the target of daratumumab (Dara). Initially, we assessed PEL cells from eight patients and established that each expressed high levels of CD38 by flow cytometry. PEL cell lines were also evaluated and most had high CD38 expression. We then assessed Dara's effects on complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) of PEL cell lines as well as its clinical benefits on two patients with PEL. Despite high CD38 expression, Dara did not induce CDC of PEL cell lines, due in part to high levels of the complement-inhibitory proteins, CD55 and CD59. However, Dara induced significant and dose-dependent increases in ADCC, particularly in those lines with high CD38 levels. Two FDA-approved drugs, all trans-retinoic acid (ATRA) and pomalidomide (Pom), significantly increased surface CD38 levels in low-CD38 expressing PEL cell lines, resulting in increased Dara-induced ADCC. Two patients with refractory PEL were treated with Dara alone or in combination with Pom. One patient with leptomeningeal PEL had a complete response to Dara and Pom combination treatment. Others had improvement in performance status and resolution of malignant ascites with Dara alone. Together, these data support the use of Dara monotherapy or in combination with ATRA or Pom as a potential therapeutic option for PEL.

Immune evasion in esophageal squamous cell cancer: From the perspective of tumor microenvironment

Esophageal cancer (EC) is one of the most life-threatening malignancies worldwide. Esophageal squamous cell carcinoma (ESCC) is the dominant subtype, accounting for approximately 90% of new incident EC each year. Although multidisciplinary treatment strategies have advanced rapidly, patients with ESCC are often diagnosed at advanced stage and the long-term prognosis remains unsatisfactory. In recent decades, immunotherapy, such as immune checkpoint inhibitors (ICIs), tumor vaccines, and chimeric antigen receptor T-cell (CAR-T) therapy, has been successfully used in clinical practice as a novel therapy for treating tumors, bringing new hope to ESCC patients. However, only a small fraction of patients achieved clinical benefits due to primary or acquired resistance. Immune evasion plays a pivotal role in the initiation and progression of ESCC. Therefore, a thorough understanding of the mechanisms by which ESCC cells escape from anti-tumor immunity is necessary for a more effective multidisciplinary treatment strategy. It has been widely recognized that immune evasion is closely associated with the crosstalk between tumor cells and the tumor microenvironment (TME). TME is a dynamic complex and comprehensive system including not only cellular components but also non-cellular components, which influence hallmarks and fates of tumor cells from the outside. Novel immunotherapy targeting tumor-favorable TME represents a promising strategy to achieve better therapeutic responses for patients with ESCC. In this review, we provide an overview of immune evasion in ESCC, mainly focusing on the molecular mechanisms that underlie the role of TME in immune evasion of ESCC. In addition, we also discuss the challenges and opportunities of precision therapy for ESCC by targeting TME.

The function of natural compounds in important anticancer mechanisms

The existence of malignant tumors has been a threat to human life, health, and safety. Although the rapid development of radiotherapy, drug therapy, surgery, and local therapy has improved the quality of life of tumor patients, there are still some risks. Natural compounds are widely used in cancer because they are easy to obtain, have a good curative effects and have no obvious side effects, and play a vital role in the prevention and treatment of various cancers. Phenolic, flavonoids, terpenoids, alkaloids, and other natural components of traditional Chinese medicine have certain anti-tumor activities, which can promote apoptosis, anti-proliferation, anti-metastasis, inhibit angiogenesis, change the morphology of cancer cells and regulate immune function, etc., and have positive effects on breast cancer, liver cancer, lung cancer, gastric cancer, rectal cancer and so on. To better understand the effects of natural compounds on cancer, this paper screened out four important pathways closely related to cancer, including cell death and immunogenic cell death, immune cells in the tumor microenvironment, inflammation and related pathways and tumor metastasis, and systematically elaborated the effects of natural compounds on cancer.

Molecular Determinants Underlying the Anti-Cancer Efficacy of CD38 Monoclonal Antibodies in Hematological Malignancies

CD38 was first discovered as a T-cell antigen and has since been found ubiquitously expressed in various hematopoietic cells, including plasma cells, NK cells, B cells, and granulocytes. More importantly, CD38 expression levels on malignant hematopoietic cells are significantly higher than counterpart healthy cells, thus presenting itself as a promising therapeutic target. In fact, for many aggressive hematological cancers, including CLL, DLBCL, T-ALL, and NKTL, CD38 expression is significantly associated with poorer prognosis and a hyperproliferative or metastatic phenotype. Studies have shown that, beyond being a biomarker, CD38 functionally mediates dysregulated survival, adhesion, and migration signaling pathways, as well as promotes an immunosuppressive microenvironment conducive for tumors to thrive. Thus, targeting CD38 is a rational approach to overcoming these malignancies. However, clinical trials have surprisingly shown that daratumumab monotherapy has not been very effective in these other blood malignancies. Furthermore, extensive use of daratumumab in MM is giving rise to a subset of patients now refractory to daratumumab treatment. Thus, it is important to consider factors modulating the determinants of response to CD38 targeting across different blood malignancies, encompassing both the transcriptional and post-transcriptional levels so that we can diversify the strategy to enhance daratumumab therapeutic efficacy, which can ultimately improve patient outcomes.

Immunotherapy resistance in esophageal cancer: Possible mechanisms and clinical implications

Esophageal cancer (EC) is a common malignant gastrointestinal (GI) cancer in adults. Although surgical technology combined with neoadjuvant chemoradiotherapy has advanced rapidly, patients with EC are often diagnosed at an advanced stage and the five-year survival rate remains unsatisfactory. The poor prognosis and high mortality in patients with EC indicate that effective and validated therapy is of great necessity. Recently, immunotherapy has been successfully used in the clinic as a novel therapy for treating solid tumors, bringing new hope to cancer patients. Several immunotherapies, such as immune checkpoint inhibitors (ICIs), chimeric antigen receptor T-cell therapy, and tumor vaccines, have achieved significant breakthroughs in EC treatment. However, the overall response rate (ORR) of immunotherapy in patients with EC is lower than 30%, and most patients initially treated with immunotherapy are likely to develop acquired resistance (AR) over time. Immunosuppression greatly weakens the durability and efficiency of immunotherapy. Because of the heterogeneity within the immune microenvironment and the highly disparate oncological characteristics in different EC individuals, the exact mechanism of immunotherapy resistance in EC remains elusive. In this review, we provide an overview of immunotherapy resistance in EC, mainly focusing on current immunotherapies and potential molecular mechanisms underlying immunosuppression and drug resistance in immunotherapy. Additionally, we discuss prospective biomarkers and novel methods for enhancing the effect of immunotherapy to provide a clear insight into EC immunotherapy.

The Immunomodulatory Role of Hypoxic Tumor-Derived Extracellular Vesicles

Simple Summary

Hypoxia, a characteristic of many cancer types, can suppress the antitumor effector functions of the adaptive and innate immune system. Tumor-cell-derived extracellular vesicles, which function as a mechanism of communication between tumor cells and immune cells, are also affected by hypoxia, and may drive immunosuppression. The aim of this review is to summarize the current knowledge on hypoxic cancer-cell-derived extracellular vesicles in immunosuppression, and to provide an overview of enriched factors (i.e., miRNA and proteins) in hypoxic tumor-derived EVs and their role in immunomodulation. This complete overview may indicate relevant directions for future research into the role of hypoxia in immunosuppression during cancer.

Abstract

Tumor-associated immune cells frequently display tumor-supportive phenotypes. These phenotypes, induced by the tumor microenvironment (TME), are described for both the adaptive and the innate arms of the immune system. Furthermore, they occur at all stages of immune cell development, up to effector function. One major factor that contributes to the immunosuppressive nature of the TME is hypoxia. In addition to directly inhibiting immune cell function, hypoxia affects intercellular crosstalk between tumor cells and immune cells. Extracellular vesicles (EVs) play an important role in this intercellular crosstalk, and changes in both the number and content of hypoxic cancer-cell-derived EVs are linked to the transfer of hypoxia tolerance. Here, we review the current knowledge about the role of these hypoxic cancer-cell-derived EVs in immunosuppression. In addition, we provide an overview of hypoxia-induced factors (i.e., miRNA and proteins) in tumor-derived EVs, and their role in immunomodulation.

Research progress in the role of CD38 in clinical tumor treatment

Tumor is one of the ten leading causes of death in the world. Traditional tumor treatments include surgery, radiation therapy, and chemotherapy. With the development of immune checkpoint blockade therapy targeting the programmed death 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) axis, the number of cancers in solid tumors has increased. Changes in the immunometabolic microenvironment have been shown to be important regulators of innate suppression of immune cell function and acquired resistance to immunotherapy. As a new target, CD38 is an enzyme that produces immunosuppressive metabolites (such as adenosine), which can be used in combination with immunotherapy to improve the clinical efficacy of tumor therapy, and can also be used as an indicator for understanding tumor immunotherapy response.

CD38: An important regulator of T cell function

Cluster of differentiation 38 (CD38) is a multifunctional extracellular enzyme on the cell surface with NADase and cyclase activities. CD38 is not only expressed in human immune cells, such as lymphocytes and plasma cells, but also is abnormally expressed in a variety of tumor cells, which is closely related to the occurrence and development of tumors. T cells are one of the important immune cells in the body. As NAD consuming enzymes, CD38, ART2, SIRT1 and PARP1 are closely related to the number and function of T cells. CD38 may also influence the activity of ART2, SIRT1 and PARP1 through the CD38-NAD⁺ axis to indirectly affect the number and function of T cells. Thus, CD38-NAD⁺ axis has a profound effect on T cell activity. In this paper, we reviewed the role and mechanism of CD38⁺ CD4⁺ T cells / CD38⁺ CD8⁺ T cells in cellular immunity and the effects of the CD38-NAD⁺ axis on T cell activity. We also summarized the relationship between the CD38 expression level on T cell surface and disease prediction and prognosis, the effects of anti-CD38 monoclonal antibodies on T cell activity and function, and the role of anti-CD38 chimeric antigen receptor (CAR) T cell therapy in tumor immunity. This will provide an important theoretical basis for a comprehensive understanding of the relationship between CD38 and T cells.

Quantitative tissue analysis and role of myeloid cells in non-small cell lung cancer

BACKGROUND

Despite the prominent role of innate immunity in the antitumor response, little is known about the myeloid composition of human non-small cell lung cancer (NSCLC) with respect to histology and molecular subtype. We used multiplexed quantitative immunofluorescence (QIF) to measure the distribution and clinical significance of major myeloid cell subsets in large retrospective NSCLC collections.

METHODS

We established a QIF panel to map major myeloid cell subsets in fixed human NSCLC including 4',6-Diamidino-2-Phenylindole for all cells, pancytokeratin for tumor-epithelial cells, CD68 for M1-like macrophages; and CD11b plus HLA-DR to interrogate mature and immature myeloid cell populations such as myeloid derived suppressor cells (MDSCs). We interrogated 793 NSCLCs represented in four tissue microarray-based cohorts: #1 (Yale, n=379) and #2 (Greece, n=230) with diverse NSCLC subtypes; #3 (Yale, n=138) with molecularly annotated lung adenocarcinomas (ADC); and #4 (Yale, n=46) with patient-matched NSCLC and morphologically-normal lung tissue. We examined associations between marker levels, myeloid cell profiles, clinicopathologic/molecular variables and survival.

RESULTS

The levels of CD68+ M1 like macrophages were significantly lower and the fraction of CD11b+/HLA-DR- MDSC-like cells was prominently higher in tumor than in matched non-tumor lung tissues. HLA-DR was consistently higher in myeloid cells from tumors with elevated CD68 expression. Stromal CD11b was significantly higher in squamous cell carcinomas (SCC) than in ADC across the cohorts and EGFR-mutated lung ADCs displayed lower CD11b levels than KRAS-mutant tumors. Increased stromal CD68- and HLA-DR-expressing cells was associated with better survival in ADCs from two independent NSCLC cohorts. In SCC, increased stromal CD11b or HLA-DR expression was associated with a trend towards shorter 5-year survival.

CONCLUSIONS

NSCLCs display an unfavorable myeloid immune contexture relative to non-tumor lung and exhibit distinct myeloid-cell profiles across histologies and presence of major oncogenic driver-mutations. Elevated M1-like stromal proinflammatory myeloid cells are prognostic in lung ADC, but not in SCC.

The Role of Tumor Microenvironment in Invasion and Metastasis of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in the world, with a high rate of morbidity. The invasion and metastasis of ESCC is the main reason for high mortality. More and more evidence suggests that metastasized cancer cells require cellular elements that contribute to ESCC tumor microenvironment (TME) formation. TME contains many immune cells and stromal components, which are critical to epithelial–mesenchymal transition, immune escape, angiogenesis/lymphangiogenesis, metastasis niche formation, and invasion/metastasis. In this review, we will focus on the mechanism of different microenvironment cellular elements in ESCC invasion and metastasis and discuss recent therapeutic attempts to restore the tumor-suppressing function of cells within the TME. It will represent the whole picture of TME in the metastasis and invasion process of ESCC.

Metastatic colorectal carcinoma-associated fibroblasts have immunosuppressive properties related to increased IGFBP2 expression

Fibroblasts are the most abundant stromal constituents of the tumour microenvironment in primary as well as metastatic colorectal cancer (CRC). Their supportive effect on tumour cells is well established. There is growing evidence that stromal fibroblasts also modulate the immune microenvironment in tumours. Here, we demonstrate a difference in fibroblast-mediated immune modulation between primary CRC and peritoneal metastasis. Cancer-associated fibroblasts (CAFs) were isolated from primary cancer and from peritoneal metastases (MAFs) from a total of 17 patients. The ectoenzyme CD38 was consistently expressed on the surface of all MAFs, while it was absent from CAFs. Furthermore, MAFs secreted higher levels of IGFBP2, CXCL2, CXCL6, CXCL12, PDGF-AA, FGFb, and IL-6. This was associated with a decreased activation of macrophages and a suppression of CD25 expression and proliferation of co-cultivated T-cells. Downregulation of IGFBP2 abolished these immunosuppressive effects of MAFs. Taken together, these results show that MAFs contribute to an immunosuppressive tumour microenvironment in CRC metastases by modulating the phenotype of immune cells through an IGFBP2-dependent mechanism.

CD38-NADase is a new major contributor to Duchenne muscular dystrophic phenotype

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle degeneration. Two important deleterious features are a Ca²⁺ dysregulation linked to Ca²⁺ influxes associated with ryanodine receptor hyperactivation, and a muscular nicotinamide adenine dinucleotide (NAD⁺) deficit. Here, we identified that deletion in mdx mice of CD38, a NAD⁺ glycohydrolase‐producing modulators of Ca²⁺ signaling, led to a fully restored heart function and structure, with skeletal muscle performance improvements, associated with a reduction in inflammation and senescence markers. Muscle NAD⁺ levels were also fully restored, while the levels of the two main products of CD38, nicotinamide and ADP‐ribose, were reduced, in heart, diaphragm, and limb. In cardiomyocytes from mdx/CD38^−/− mice, the pathological spontaneous Ca²⁺ activity was reduced, as well as in myotubes from DMD patients treated with isatuximab (SARCLISA^®) a monoclonal anti‐CD38 antibody. Finally, treatment of mdx and utrophin–dystrophin‐deficient (mdx/utr^−/−) mice with CD38 inhibitors resulted in improved skeletal muscle performances. Thus, we demonstrate that CD38 actively contributes to DMD physiopathology. We propose that a selective anti‐CD38 therapeutic intervention could be highly relevant to develop for DMD patients.

The CD38 glycohydrolase and the NAD sink: implications for pathological conditions

Nicotinamide adenine dinucleotide (NAD) acts as a cofactor in several oxidation-reduction (redox) reactions and is a substrate for a number of nonredox enzymes. NAD is fundamental to a variety of cellular processes including energy metabolism, cell signaling, and epigenetics. NAD homeostasis appears to be of paramount importance to health span and longevity, and its dysregulation is associated with multiple diseases. NAD metabolism is dynamic and maintained by synthesis and degradation. The enzyme CD38, one of the main NAD-consuming enzymes, is a key component of NAD homeostasis. The majority of CD38 is localized in the plasma membrane with its catalytic domain facing the extracellular environment, likely for the purpose of controlling systemic levels of NAD. Several cell types express CD38, but its expression predominates on endothelial cells and immune cells capable of infiltrating organs and tissues. Here we review potential roles of CD38 in health and disease and postulate ways in which CD38 dysregulation causes changes in NAD homeostasis and contributes to the pathophysiology of multiple conditions. Indeed, in animal models the development of infectious diseases, autoimmune disorders, fibrosis, metabolic diseases, and age-associated diseases including cancer, heart disease, and neurodegeneration are associated with altered CD38 enzymatic activity. Many of these conditions are modified in CD38-deficient mice or by blocking CD38 NADase activity. In diseases in which CD38 appears to play a role, CD38-dependent NAD decline is often a common denominator of pathophysiology. Thus, understanding dysregulation of NAD homeostasis by CD38 may open new avenues for the treatment of human diseases.

CD38 a biomarker and therapeutic target in non-hematopoietic tumors

The type II transmembrane glycoprotein CD38 has recently been implicated in regulating metabolism and the pathogenesis of multiple conditions, including aging, inflammation and cancer. CD38 is overexpressed in several tumor cells and microenvironment tumoral cells, associated to migration, angiogenesis, cell invasion and progression of the disease. Thus, CD38 has been used as a progression marker for different cancer types as well as in immunotherapy. This review focuses on describing the involvement of CD38 in various non-hematopoietic cancers.

Immunological and Metabolic Alterations in Esophageal Cancer

Esophageal cancer is one of the most common types of gastrointestinal malignancies that is encountered. It has a global distribution and affects males and females and is linked to significant morbidity and mortality. The mechanisms underlying pathophysiology are multifactorial and involve the interaction of genetic and environmental factors. This review article describes the immunological and metabolic changes that occur in malignancy of the esophagus.

Role of immune escape in different digestive tumours

A counterbalance between immune cells and tumour cells is key to fighting tumours, and immune escape is an important mechanism for the survival of tumour cells in the body. Tumor cells and their cytokines impair the activity of T cells, NK cells, macrophages and other immune cells through various ways, and change the expression of their own surface antigens so as to avoid the clearance of the immune system. Changes in major histocompatibility complex molecules, high expression of programmed death-ligand 1, and the presence of immunosuppressive cells in the tumor microenvironment (TME) are main means by which tumors impair the function of immune cells. During the development of tumours of the digestive system, different mechanisms acting on tumour cells, the TME, and immune cells lead to immune escape and promote tumour progression. In this paper, the mechanisms of immune escape in tumour cells of the digestive system are reviewed to provide a theoretical basis for the immunotherapy of gastrointestinal tumours.

Alphavirus-Driven Interferon Gamma (IFNg) Expression Inhibits Tumor Growth in Orthotopic 4T1 Breast Cancer Model

Interferon gamma (IFNg) is a pleiotropic cytokine that can potentially reprogram the tumor microenvironment; however, the antitumor immunomodulatory properties of IFNg still need to be validated due to variable therapeutic outcomes in preclinical and clinical studies. We developed a replication-deficient Semliki Forest virus vector expressing IFNg (SFV/IFNg) and evaluated its immunomodulatory antitumor potential in vitro in a model of 3D spheroids and in vivo in an immunocompetent 4T1 mouse breast cancer model. We demonstrated that SFV-derived, IFN-g-stimulated bone marrow macrophages can be used to acquire the tumoricidal M1 phenotype in 3D nonattached conditions. Coculturing SFV/IFNg-infected 4T1 spheroids with BMDMs inhibited spheroid growth. In the orthotopic 4T1 mouse model, intratumoral administration of SFV/IFNg virus particles alone or in combination with the Pam3CSK4 TLR2/1 ligand led to significant inhibition of tumor growth compared to the administration of the control SFV/Luc virus particles. Analysis of the composition of intratumoral lymphoid cells isolated from tumors after SFV/IFNg treatment revealed increased CD4⁺ and CD8⁺ and decreased T-reg (CD4⁺/CD25⁺/FoxP3⁺) cell populations. Furthermore, a significant decrease in the populations of cells bearing myeloid cell markers CD11b, CD38, and CD206 was observed. In conclusion, the SFV/IFNg vector induces a therapeutic antitumor T-cell response and inhibits myeloid cell infiltration in treated tumors.

A bispecific CAR-T cell therapy targeting BCMA and CD38 in relapsed or refractory multiple myeloma

Background

BCMA-specific chimeric antigen receptor-T cells (CAR-Ts) have exhibited remarkable efficacy in refractory or relapsed multiple myeloma (RRMM); however, primary resistance and relapse exist with single-target immunotherapy. Bispecific CARs are proposed to mitigate these limitations.

Methods

We constructed a humanized bispecific BM38 CAR targeting BCMA and CD38 and tested the antimyeloma activity of BM38 CAR-Ts in vitro and in vivo. Twenty-three patients with RRMM received infusions of BM38 CAR-Ts in a phase I trial.

Results

BM38 CAR-Ts showed stronger in vitro cytotoxicity to heterogeneous MM cells than did T cells expressing an individual BCMA or CD38 CAR. BM38 CAR-Ts also exhibited potent antimyeloma activity in xenograft mouse models. In the phase I trial, cytokine release syndrome occurred in 20 patients (87%) and was mostly grade 1–2 (65%). Neurotoxicity was not observed. Hematologic toxicities were common, including neutropenia in 96% of the patients, leukopenia in 87%, anemia in 43% and thrombocytopenia in 61%. At a median follow-up of 9.0 months (range 0.5 to 18.5), 20 patients (87%) attained a clinical response and minimal residual disease-negativity (≤ 10^–4 nucleated cells), with 12 (52%) achieving a stringent complete response. Extramedullary plasmacytoma was eliminated completely in 56% and partially in 33% and of 9 patients. The median progression-free survival was 17.2 months. Two relapsed patients maintained BCMA and CD38 expression on MM cells. Notably, BM38 CAR-Ts cells were detectable in 77.8% of evaluable patients at 9 months and 62.2% at 12 months.

Conclusion

Bispecific BM38 CAR-Ts were feasible, safe and significantly effective in patient with RRMM.

Trial registration: Chictr.org.cn ChiCTR1800018143.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01170-7.

Regulatory T-Cells and Multiple Myeloma: Implications in Tumor Immune Biology and Treatment

Multiple myeloma (MM) is associated with both cellular and humoral immune deficiencies and, despite significant advances in treatment, remains an incurable disease. Regulatory T-cells (Tregs) represent a critical subset of CD4 T-cells, characterized by CD4 + CD25+ Forkhead box P3+ (FoxP3+) phenotype, able to control peripheral tolerance and responses to foreign and tumor antigens. Tregs are elevated in various types of cancer, including hematological malignancies; in MM, data regarding Tregs function and numbers and their correlation with survival parameters are controversial. Advances in cancer biology have shown that the tumor microenvironment plays an important role in tumor progression. In MM, the highly immunosuppressive nature of the bone marrow microenvironment has been significantly elucidated in the past decade and it is now well acknowledged that targeting only the tumor clone may not be able to cure MM. Tregs within the tumor microenvironment might play a significant role in the suppression of antitumor immune responses against cancer cells and are considered to predict poor outcome in cancer patients; nonetheless the exact prognostic significance of this cell subpopulation in malignancies is still a matter of debate. In this review, we discuss the role of Tregs as an essential cell population of the MM immune microenvironment.

Oncolytic herpes virus G47Δ works synergistically with CTLA-4 inhibition via dynamic intratumoral immune modulation

Oncolytic virus therapy can increase the immunogenicity of tumors and remodel the immunosuppressive tumor microenvironment, leading to an increased antitumor response to immune-checkpoint inhibitors. Here, we investigated the therapeutic potential of G47Δ, a third-generation oncolytic herpes simplex virus type 1, in combination with immune-checkpoint inhibitors using various syngeneic murine subcutaneous tumor models. Intratumoral inoculations with G47Δ and systemic anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody administration caused an enhanced antitumor activity when combined and worked synergistically. Conversely, the efficacy of G47Δ in combination with anti-programmed cell death protein-1 (PD-1) antibody was equivalent to that of the anti-PD-1 antibody alone in all murine models examined. The combination of intratumoral G47Δ and systemic anti-CTLA-4 antibody was shown to recruit effector T cells into the tumor efficiently while decreasing regulatory T cells. Furthermore, a wide range of gene signatures related to inflammation, lymphoid lineage, and T cell activation was highly upregulated with the combination therapy, suggesting the conversion of immune-insusceptible tumors to immune susceptible. The therapeutic effect proved tumor specific and long lasting. Immune cell subset depletion studies demonstrated that CD4⁺ T cells were required for synergistic curative activity. The results depict the dynamics of immune modulation of the tumor microenvironment and provide a clinical rationale for using G47Δ with immune checkpoint inhibitors.

Tumor Microenvironment of Esophageal Cancer

Simple Summary

Esophageal cancer is one of the top ten most deadly cancers. Even when diagnosed in a curable stage, patients prognosis poor. One of the parameters that is very relevant for long-term survival is response to radio(chemo)therapy prior surgery. Complete response rates are between 24 and 50 percent. This puts more than a half of every esophageal cancer patient that is diagnosed in a non-metastasized stage at high risk of recurrence. To improve response rates of treatment regimens prior curative surgery is, therefore, a major challenge in treating esophageal cancer. Not only the response of the cancer cell itself to cancer therapy is determining patients’ fate. Cells around the tumor cells called the tumor microenvironment that together with the cancer cell constitute a malignant tumor are also involved in tumor progression and therapy response. This review depicts the most important parts of the esophageal cancer microenvironment, evaluates chances and challenges of current already established therapeutic concepts that target this microenvironment. It furthermore elucidates specific pathways that are potential valuable targets in the future.

Abstract

Esophageal cancer is among the top ten most deadly cancers worldwide with adenocarcinomas of the esophagus showing increasing incidences over the last years. The prognosis is determined by tumor stage at diagnosis and in locally advanced stages by response to (radio-)chemotherapy followed by radical surgery. Less than a third of patients with esophageal adenocarcinomas completely respond to neoadjuvant therapies which urgently asks for further strategies to improve these rates. Aiming at the tumor microenvironment with novel targeted therapies can be one strategy to achieve this goal. This review connects experimental, translational, and clinical findings on each component of the esophageal cancer tumor microenvironment involving tumor angiogenesis, tumor-infiltrating immune cells, such as macrophages, T-cells, myeloid-derived suppressor cells, and cancer-associated fibroblasts. The review evaluates the current state of already approved concepts and depicts novel potentially targetable pathways related to esophageal cancer tumor microenvironment.

Proteomic signatures of myeloid derived suppressor cells from liver and lung metastases reveal functional divergence and potential therapeutic targets

Myeloid-derived suppressor cells (MDSCs) promote immunosuppressive activities in the tumor microenvironment (TME), resulting in increased tumor burden and diminishing the anti-tumor response of immunotherapies. While primary and metastatic tumors are typically the focal points of therapeutic development, the immune cells of the TME are differentially programmed by the tissue of the metastatic site. In particular, MDSCs are programmed uniquely within different organs in the context of tumor progression. Given that MDSC plasticity is shaped by the surrounding environment, the proteomes of MDSCs from different metastatic sites are hypothesized to be unique. A bottom-up proteomics approach using sequential window acquisition of all theoretical mass spectra (SWATH-MS) was used to quantify the proteome of CD11b⁺ cells derived from murine liver metastases (LM) and lung metastases (LuM). A comparative proteomics workflow was employed to compare MDSC proteins from LuM (LuM-MDSC) and LM (LM-MDSC) while also elucidating common signaling pathways, protein function, and possible drug-protein interactions. SWATH-MS identified 2516 proteins from 200 µg of sample. Of the 2516 proteins, 2367 have matching transcriptomic data. Upregulated proteins from lung and liver-derived murine CD11b⁺ cells with matching mRNA transcriptomic data were categorized based on target knowledge and level of drug development. Comparative proteomic analysis demonstrates that liver and lung tumor-derived MDSCs have distinct proteomes that may be subject to pharmacologic manipulation.

Advances of Tumorigenesis, Diagnosis at Early Stage, and Cellular Immunotherapy in Gastrointestinal Malignancies

Globally, in 2018, 4.8 million new patients have a diagnosis of gastrointestinal (GI) cancers, while 3.4 million people died of such disorders. GI malignancies are tightly relevant to 26% of the world-wide cancer incidence and occupies 35% of all cancer-associated deaths. In this article, we principally investigated molecular and cellular mechanisms of tumorigenesis in five major GI cancers occurring at esophagus, stomach, liver, pancreas, and colorectal region that illustrate high morbidity in Eastern and Western countries. Moreover, through this investigation, we not only emphasize importance of the tumor microenvironment in development and treatment of malignant tumors but also identify significance of M2PK, miRNAs, ctDNAs, circRNAs, and CTCs in early detection of GI cancers, as well as systematically evaluate contribution of personalized precision medicine including cellular immunotherapy, new antigen and vaccine therapy, and oncolytic virotherapy in treatment of GI cancers.

Inhibition of WHSC1 Allows for Reprogramming of the Immune Compartment in Prostate Cancer

Immunotherapy initially demonstrated promising results in prostate cancer (PCa), but the modest or negative results of many recent trials highlight the need to overcome the poor immunogenicity of this cancer. The design of effective therapies for PCa is challenged by the limited understanding of the interface between PCa cells and the immune system in mediating therapeutic resistance. Prompted by our recent observations that elevated WHSC1, a histone methyltransferase known to promote progression of numerous cancers, can silence antigen processing and presentation in PCa, we performed a single-cell analysis of the intratumoral immune dynamics following in vivo pharmacological inhibition of WHSC1 in mice grafted with TRAMP C2 cells. We observed an increase in cytotoxic T and NK cells accumulation and effector function, accompanied by a parallel remodeling of the myeloid compartment, as well as abundant shifts in key ligand–receptor signaling pathways highlighting changes in cell-to-cell communication driven by WHSC1 inhibition. This comprehensive profiling of both immune and molecular changes during the course of WHSC1 blockade deepens our fundamental understanding of how anti-tumor immune responses develop and can be enhanced therapeutically for PCa.

The tumour immune microenvironment in oesophageal cancer

Oesophageal cancer (OC) is an inflammation-associated malignancy linked to gastro-oesophageal reflux disease, obesity and tobacco use. Knowledge of the microenvironment of oesophageal tumours is relevant to our understanding of the development of OC and its biology, and has major implications for understanding the response to standard therapies and immunotherapies, as well as for uncovering novel targets. In this context, we discuss what is known about the TME in OC from tumour initiation to development and progression, and how this is relevant to therapy sensitivity and resistance in the two major types of OC. We provide an immunological characterisation of the OC TME and discuss its prognostic implications with specific comparison with the Immunoscore and immune-hot, -cold, altered-immunosuppressed and -altered-excluded models. Targeted therapeutics for the TME under pre-clinical and clinical investigation in OCs are also summarised. A deeper understanding of the TME will enable the development of combination approaches to concurrently target the tumour cells and TME delivering precision medicine to OC patients.

Understanding the immuno-biology of oesophageal adenocarcinoma: Towards improved therapeutic approaches

With an incidence that is constantly rising, oesophageal adenocarcinoma (OAC) is becoming an increasing health burden worldwide. Although significant advances in treatment regimens have improved patient outcomes, survival rates for this deadly cancer remain unsatisfactory. This highlights the need to improve current therapeutic approaches and develop novel therapeutic strategies for treating OAC patients. The advent of immunotherapy has revolutionised treatment across a range of malignancies, however outcomes in OAC show modest results. The inherent resistance of OAC to treatment reflects the complex genomic landscape of this cancer, which displays a lack of ubiquitous driver mutations and large-scale genomic alterations along with high tumour and immune heterogeneity. Research into the immune landscape of OAC is limited, and elucidation of the mechanisms surrounding the immune responses to this complex cancer will result in improved therapeutic approaches. This review explores what is known about the immuno-biology of OAC and explores promising therapeutic avenues that may improve responses to immunotherapeutic regimens.