Regulatory T (Treg) cells in cancer: Can Treg cells be a new therapeutic target?

CD80 Expression on Tumor Cells Alters Tumor Microenvironment and Efficacy of Cancer Immunotherapy by CTLA-4 Blockade

Cluster of differentiation (CD) 80 is mainly expressed in immune cells but can also be found in several types of cancer cells. This molecule may either activate or inhibit immune reactions. Here, we determined the immunosuppressive role of CD80 in the tumor microenvironment by CRISPR/Cas9-mediated deactivation of the corresponding gene in the mouse oncogenic TC-1 cell line. The tumor cells with deactivated CD80 (TC-1/dCD80-1) were more immunogenic than parental cells and induced tumors that gained sensitivity to cytotoxic T-lymphocyte antigen 4 (CTLA-4) blockade, as compared with the TC-1 cells. In vivo depletion experiments showed that the deactivation of CD80 switched the pro-tumorigenic effect of macrophages observed in TC-1-induced tumors into an anti-tumorigenic effect in TC-1/dCD80-1 tumors and induced the pro-tumorigenic activity of CD4⁺ cells. Moreover, the frequency of lymphoid and myeloid cells and the CTLA-4 expression by T helper (Th)17 cells were increased in TC-1/dCD80-1- compared with that in the TC-1-induced tumors. CTLA-4 blockade downregulated the frequencies of most immune cell types and upregulated the frequency of M2 macrophages in the TC-1 tumors, while it increased the frequency of lymphoid cells in TC-1/dCD80-1-induced tumors. Furthermore, the anti-CTLA-4 therapy enhanced the frequency of CD8⁺ T cells as well as CD4⁺ T cells, especially for a Th1 subset. Regulatory T cells (Treg) formed the most abundant CD4⁺ T cell subset in untreated tumors. The anti-CTLA-4 treatment downregulated the frequency of Treg cells with limited immunosuppressive potential in the TC-1 tumors, whereas it enriched this type of Treg cells and decreased the Treg cells with high immunosuppressive potential in TC-1/dCD80-1-induced tumors. The immunosuppressive role of tumor-cell-expressed CD80 should be considered in research into biomarkers for the prediction of cancer patients' sensitivity to immune checkpoint inhibitors and for the development of a tumor-cell-specific CD80 blockade.

Role of immune regulatory cells in breast cancer: Foe or friend?

Breast cancer (BC) is the most common cancer among women between the ages of 20 and 50, affecting more than 2.1 million people and causing the annual death of more than 627,000 women worldwide. Based on the available knowledge, the immune system and its components are involved in the pathogenesis of several malignancies, including BC. Cancer immunobiology suggests that immune cells can play a dual role and induce anti-tumor or immunosuppressive responses, depending on the tumor microenvironment (TME) signals. The most important effector immune cells with anti-tumor properties are natural killer (NK) cells, B, and T lymphocytes. On the other hand, immune and non-immune cells with regulatory/inhibitory phenotype, including regulatory T cells (Tregs), regulatory B cells (Bregs), tolerogenic dendritic cells (tDCs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), myeloid-derived suppressor cells (MDSCs), mesenchymal stem cells (MSCs), and regulatory natural killer cells (NKregs), can promote the growth and development of tumor cells by inhibiting anti-tumor responses, inducing angiogenesis and metastasis, as well as the expression of inhibitory molecules and suppressor mediators of the immune system. However, due to the complexity of the interaction and the modification in the immune cells' phenotype and the networking of the immune responses, the exact mechanism of action of the immunosuppressive and regulatory cells is not yet fully understood. This review article reviews the immune responses involved in BC as well as the role of regulatory and inhibitory cells in the pathogenesis of the disease. Finally, therapeutic approaches based on inhibition of immunosuppressive responses derived from regulatory cells are discussed.

Research progress in tumor targeted immunotherapy

INTRODUCTION

Compared with traditional cancer treatment methods, tumor-targeted immunotherapy can combine targeted therapy and immunotherapy with long-lasting responses to achieve synergistic therapy, which brings hope to the complete cure of cancer.

AREAS COVERED

This review summarizes the newest and most up-to-date advances in tumor-targeted immunotherapy, including tumor-associated macrophages (TAMs) targeted immunotherapy, regulatory T (Treg) cells targeted immunotherapy, tumor-associated fibroblasts (TAFs) targeted immunotherapy and immune checkpoints targeted immunotherapy.

EXPERT OPINION

Immunotherapy can restore anti-tumor immunity in the tumor microenvironment and produce a lasting immune surveillance effect. Smart multifunctional nano delivery system can effectively combine targeted therapy with immunotherapy, which has attracted extensive attention. With the deepening of research, more and more tumor-targeted immunotherapy enter into the clinical trial phases, especially antibodies and inhibitors. Tumor-targeted immunotherapy is a promising approach for conquering cancer and bringing hope for human health.

Metabolites in the Tumor Microenvironment Reprogram Functions of Immune Effector Cells Through Epigenetic Modifications

Cellular metabolism of both cancer and immune cells in the acidic, hypoxic, and nutrient-depleted tumor microenvironment (TME) has attracted increasing attention in recent years. Accumulating evidence has shown that cancer cells in TME could outcompete immune cells for nutrients and at the same time, producing inhibitory products that suppress immune effector cell functions. Recent progress revealed that metabolites in the TME could dysregulate gene expression patterns in the differentiation, proliferation, and activation of immune effector cells by interfering with the epigenetic programs and signal transduction networks. Nevertheless, encouraging studies indicated that metabolic plasticity and heterogeneity between cancer and immune effector cells could provide us the opportunity to discover and target the metabolic vulnerabilities of cancer cells while potentiating the anti-tumor functions of immune effector cells. In this review, we will discuss the metabolic impacts on the immune effector cells in TME and explore the therapeutic opportunities for metabolically enhanced immunotherapy.

Combined Effects of Myeloid Cells in the Neuroblastoma Tumor Microenvironment

Despite multimodal treatment, survival chances for high-risk neuroblastoma patients remain poor. Immunotherapeutic approaches focusing on the activation and/or modification of host immunity for eliminating tumor cells, such as chimeric antigen receptor (CAR) T cells, are currently in development, however clinical trials have failed to reproduce the preclinical results. The tumor microenvironment is emerging as a major contributor to immune suppression and tumor evasion in solid cancers and thus has to be overcome for therapies relying on a functional immune response. Among the cellular components of the neuroblastoma tumor microenvironment, suppressive myeloid cells have been described as key players in inhibition of antitumor immune responses and have been shown to positively correlate with more aggressive disease, resistance to treatments, and overall poor prognosis. This review article summarizes how neuroblastoma-driven inflammation induces suppressive myeloid cells in the tumor microenvironment and how they in turn sustain the tumor niche through suppressor functions, such as nutrient depletion and generation of oxidative stress. Numerous preclinical studies have suggested a range of drug and cellular therapy approaches to overcome myeloid-derived suppression in neuroblastoma that warrant evaluation in future clinical studies.

Adoptive T Cell Therapy for Solid Tumors: Pathway to Personalized Standard of Care

Adoptive cell therapy (ACT) with tumor-infiltrating T cells (TILs) has emerged as a promising therapy for the treatment of unresectable or metastatic solid tumors. One challenge to finding a universal anticancer treatment is the heterogeneity present between different tumors as a result of genetic instability associated with tumorigenesis. As the epitome of personalized medicine, TIL-ACT bypasses the issue of intertumoral heterogeneity by utilizing the patient’s existing antitumor immune response. Despite being one of the few therapies capable of inducing durable, complete tumor regression, many patients fail to respond. Recent research has focused on increasing therapeutic efficacy by refining various aspects of the TIL protocol, which includes the isolation, ex vivo expansion, and subsequent infusion of tumor specific lymphocytes. This review will explore how the therapy has evolved with time by highlighting various resistance mechanisms to TIL therapy and the novel strategies to overcome them.

Development of Anti-Mouse CC Chemokine Receptor 8 Monoclonal Antibodies for Flow Cytometry

CC chemokine receptor 8 (CCR8) belongs to the class A of G protein-coupled receptor. It is highly expressed on Treg and T helper 2 (T_H2) cells recruited to the inflammation site and is implicated in allergy and asthma. Recently, CCR8+Treg cells have been suggested to be a master regulator in the immunosuppressive tumor microenvironment; therefore, developing sensitive monoclonal antibodies (mAbs) for CCR8 has been desired. This study established a specific and sensitive mAb for mouse CCR8 (mCCR8), which is useful for flow cytometry by using the Cell-Based Immunization and Screening (CBIS) method. The established anti-mCCR8 mAb, C₈Mab-2 (rat IgG_2b, kappa), reacted with mCCR8-overexpressed Chinese hamster ovary-K1 (CHO/mCCR8) cells and P388 (mouse lymphoid neoplasma) or J774-1 (mouse macrophage-like) cells, which express endogenous mCCR8 by flow cytometry. C₈Mab-2, which was established by the CBIS method, could be useful for elucidating the mCCR8-related biological response by flow cytometry.

Bacteria-Based Cancer Immunotherapy

In the past decade, bacteria-based cancer immunotherapy has attracted much attention in the academic circle due to its unique mechanism and abundant applications in triggering the host anti-tumor immunity. One advantage of bacteria lies in their capability in targeting tumors and preferentially colonizing the core area of the tumor. Because bacteria are abundant in pathogen-associated molecular patterns that can effectively activate the immune cells even in the tumor immunosuppressive microenvironment, they are capable of enhancing the specific immune recognition and elimination of tumor cells. More attractively, during the rapid development of synthetic biology, using gene technology to enable bacteria to be an efficient producer of immunotherapeutic agents has led to many creative immunotherapy paradigms. The combination of bacteria and nanomaterials also displays infinite imagination in the multifunctional endowment for cancer immunotherapy. The current progress report summarizes the recent advances in bacteria-based cancer immunotherapy with specific foci on the applications of naive bacteria-, engineered bacteria-, and bacterial components-based cancer immunotherapy, and at the same time discusses future directions in this field of research based on the present developments.

Identification of an Immune Gene Signature Based on Tumor Microenvironment Characteristics in Colon Adenocarcinoma

Tumor microenvironment (TME) changes are related to the occurrence and development of colon adenocarcinoma (COAD). This study aimed to analyze the characteristics of the immune microenvironment in CC, as well as the microenvironment's relationship with the clinical features of CC. Based on The Cancer Genome Atlas (TCGA) and GSE39582 cohorts, the scores of 22 tumor infiltrating lymphocytes (TILs) were calculated using CIBERSORT. ConsensusClusterPlus was used for unsupervised clustering. Three TME subtypes (TMEC1, TMEC2, and TME3) were identified based on TIL scores. TMEC2 was associated with the worst prognosis. Random forest, k-means clustering, and principal component analysis were used to construct the TME score risk signature. The median TME score was used to divide the samples into high- and low-risk groups. The prognoses of the patients with high TME scores were worse than those of the patients with low TME scores. A high TME score was an independent prognostic risk factor for patients with colon cancer. The Gene Set Enrichment Analysis (GSEA) results showed that those with high TME scores were enriched in FOCAL_ADHESION, ECM_RECEPTOR_INTERACTION, and PATHWAYS_IN_CANCER. Our findings will provide a new strategy for immunotherapy in patients with CC.

Nano-delivery systems focused on tumor microenvironment regulation and biomimetic strategies for treatment of breast cancer metastasis

Breast cancer metastasis and recurrence accounts for vast majority of breast cancer-induced mortality. Tumor microenvironment (TME) plays an important role at each step of metastasis, evasion of immunosurveillance, and therapeutic resistance. Consequently, TME-targeting alternatives to traditional therapies focused on breast cancer cells are gaining increasing attention. These new therapies involve the use of tumor cells, and key TME components or secreted bioactive molecules as therapeutic targets, alone or in combination. Recently, TME-related nanoparticles have been developed to deliver various agents, such as bioactive ingredients extracted from natural sources or chemotherapeutic agents, genes, proteins, small interfering RNAs, and vaccines; they have shown great therapeutic potential against breast cancer metastasis. Among various types of nanoparticles, biomimetic nanovesicles are a promising means of addressing the limitations of conventional nanocarriers. This review highlights various nanoparticles related to or mediated by TME according to the key TME components responsible for metastasis. Furthermore, TME-related biomimetic nanoparticles against breast cancer metastasis have garnered attention owing to their promising efficiency, especially in payload delivery and therapeutic action. Here, we summarize recent representative studies on nanoparticles related to cancer-associated fibroblasts, extracellular matrix, endothelial cells, angiogenesis, and immune cells, as well as advanced biomimetic nanoparticles. Future challenges and opportunities in the field are also discussed.

The Role of CXCL16 in the Pathogenesis of Cancer and Other Diseases

CXCL16 is a chemotactic cytokine belonging to the α-chemokine subfamily. It plays a significant role in the progression of cancer, as well as the course of atherosclerosis, renal fibrosis, and non-alcoholic fatty liver disease (NAFLD). Since there has been no review paper discussing the importance of this chemokine in various diseases, we have collected all available knowledge about CXCL16 in this review. In the first part of the paper, we discuss background information about CXCL16 and its receptor, CXCR6. Next, we focus on the importance of CXCL16 in a variety of diseases, with an emphasis on cancer. We discuss the role of CXCL16 in tumor cell proliferation, migration, invasion, and metastasis. Next, we describe the role of CXCL16 in the tumor microenvironment, including involvement in angiogenesis, and its significance in tumor-associated cells (cancer associated fibroblasts (CAF), microglia, tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), mesenchymal stem cells (MSC), myeloid suppressor cells (MDSC), and regulatory T cells (T_reg)). Finally, we focus on the antitumor properties of CXCL16, which are mainly caused by natural killer T (NKT) cells. At the end of the article, we summarize the importance of CXCL16 in cancer therapy.

Co-inhibitor expression on tumor infiltrating and splenic lymphocytes after dual checkpoint inhibition in a microsatellite stable model of colorectal cancer

Checkpoint inhibitors have demonstrated clinical impact in colorectal cancer with deficient mismatch repair and high microsatellite instability. However, the majority of patients have disease with stable microsatellites that responds poorly to immunotherapies. Combinations of checkpoint inhibitors are under investigation as a way of increasing immunogenicity and promoting a robust anti-tumor immune response. The purpose of this study is to quantify the immune responses induced by mono and dual checkpoint inhibition in a mismatch repair proficient model of colorectal cancer (CRC). Tumor growth rates were monitored over time and compared between groups. We utilized fluorescence-activated cell sorting to analyze CD8⁺ and CD4⁺ T cells after treatment with either single PD-1 inhibition or dual PD-1 and CTLA-4 inhibition. Additionally, we sought to quantify the expression of co-inhibitory surface molecules PD-1, LAG3, and TIM3. Dual checkpoint inhibition was associated with a significantly slower growth rate as compared to either mono PD-1 inhibition or control (p < 0.05). Neither monotherapy nor dual checkpoint inhibition significantly affected the tumoral infiltration of lymphocytes. After treatment with dual inhibitors, infiltrating CD8⁺ T cells demonstrated significantly less expression of PD-1 (1700 vs. 2545 and 2462; p < 0.05) and LAG3 (446.2 vs. 694.4 and 707; p < 0.05) along with significantly more expression of TIM3 (12,611 vs. 2961 and 4259; p < 0.05) versus the control and anti-PD-1 groups. These results suggest that dual therapy with anti-CTLA-4 and anti-PD-1 antibodies significantly inhibits growth of microsatellite stable CRC by suppressing immunosuppressive checkpoints. Upregulation of TIM3 represents a potential escape mechanism and a target for future combination immunotherapies in CRC.

The characteristics of the immune cell profiles in peripheral blood in cholangiocarcinoma patients

BACKGROUND

Immune related cells are known to be closely related to the therapeutic effects and prognoses of cancer patients. In this study, we analyzed immune cell profiles (ICP) of cholangiocarcinoma patients (CCA).

METHODS

To measure the frequency of immune cells, peripheral blood mononuclear cells of 41 CCA and 10 healthy volunteers (HV) were analyzed by FACS.

RESULTS

There were significant differences between CCA and HV in ICP, and these differences were a consequence of tumor-bearing status, because many items in ICP before surgery were restored to levels in HV after surgery. Therefore, these changes were specifically attributable to cholangiocarcinoma, and we examined if they can function as biomarkers for therapeutic effects and prognoses. A shorter overall survival was associated with a lower frequency of helper T cells (HT) (p = 0.001), a higher frequency of effector regulatory T cells (eTregs) (p = 0.008), and a lower frequency of CD80 + eTregs (p = 0.024) in the best supportive care group, with a lower frequency of CD25 + naïve Tregs (nTregs) (p = 0.005) in the chemotherapy group, and with a lower frequency of OX40 + HT (p = 0.022), CD25 + CD8 + T cells (p = 0.017), and OX40 + CD8 + T cells (p = 0.032) in the surgery group. The recurrence factors were a higher frequency of CD4 + T cells (p = 0.009), CCR6 + nTregs (p = 0.014), and CXCR3 + nTregs (p = 0.012), and a lower frequency of PD-1 + HT (p = 0.006), OX40 + HT (p = 0.004), CD8 + T cells (p = 0.001), and CTLA-4 + CD8 + T cells (p = 0.036).

CONCLUSIONS

The ICP in CCA are specifically attributable to cholangiocarcinoma, and may be biomarkers for therapeutic effects and prognoses.

Immune System Alterations in Multiple Myeloma: Molecular Mechanisms and Therapeutic Strategies to Reverse Immunosuppression

Simple Summary

A common characteristic of multiple myeloma (MM) is the dysfunction of patients’ immune system, a condition termed immunosuppression. This state is mainly due to alterations in the number and functionality of the principal immune populations. In this setting, immunotherapy has acquired high relevance in the last years and the investigation of agents that boost the immune system represent a field of interest. In the present review, we will summarize the main cellular and molecular alterations observed in MM patients’ immune system. Furthermore, we will describe the mechanisms of action of the four immunotherapeutic drugs approved so far for the treatment of MM, which are part of the group of monoclonal antibodies (mAbs). Finally, the immune-stimulating effects of several therapeutic agents are described due to their potential role in reversing immunosuppression and, therefore, in favoring the efficacy of immunotherapy drugs, such as mAbs, as part of future pharmacological combinations.

Abstract

Immunosuppression is a common feature of multiple myeloma (MM) patients and has been associated with disease evolution from its precursor stages. MM cells promote immunosuppressive effects due to both the secretion of soluble factors, which inhibit the function of immune effector cells, and the recruitment of immunosuppressive populations. Alterations in the expression of surface molecules are also responsible for immunosuppression. In this scenario, immunotherapy, as is the case of immunotherapeutic monoclonal antibodies (mAbs), aims to boost the immune system against tumor cells. In fact, mAbs exert part of their cytotoxic effects through different cellular and soluble immune components and, therefore, patients’ immunosuppressive status could reduce their efficacy. Here, we will expose the alterations observed in symptomatic MM, as compared to its precursor stages and healthy subjects, in the main immune populations, especially the inhibition of effector cells and the activation of immunosuppressive populations. Additionally, we will revise the mechanisms responsible for all these alterations, including the interplay between MM cells and immune cells and the interactions among immune cells themselves. We will also summarize the main mechanisms of action of the four mAbs approved so far for the treatment of MM. Finally, we will discuss the potential immune-stimulating effects of non-immunotherapeutic drugs, which could enhance the efficacy of immunotherapeutic treatments.

IL17A Depletion Affects the Metabolism of Macrophages Treated with Gemcitabine

BACKGROUND

Interleukin (IL)17A is a member of the IL17 cytokine family, which is released by both immune and non-immune cells such as tumor and stromal cells into the tumor microenvironment. IL17 receptors are also widely expressed in different type of cells. Among all the members, IL17A is the most controversial in regulating tumor immunity. Here, we investigated how IL17A inhibition modulated macrophage differentiation and metabolism in the presence or absence of gemcitabine. Gemcitabine is the gold standard drug for treating pancreatic cancer and can increase macrophage antitumoral activities.

RESULTS

We observed some unique features of macrophages polarized in the absence of IL17A, in terms of RNA and protein expression of typical phenotypic markers, and we demonstrated that this paralleled specific changes in their metabolism and functions, such as the induction of an antitumor response. Interestingly, these features were almost maintained or enhanced when macrophages were treated with gemcitabine. We also demonstrated that the anti-IL17A antibody effectively reproduced features of macrophages derived from IL17A knock-out mice.

CONCLUSION

Overall, we provide a proof-of-concept that combining an anti-IL17A antibody with gemcitabine may represent an effective strategy to modulate macrophages and enhance the anti-tumor response, especially in pancreatic cancer where gemcitabine is widely used.

Safety and activity of the TGFβ receptor I kinase inhibitor galunisertib plus the anti-PD-L1 antibody durvalumab in metastatic pancreatic cancer

Background

We assessed the safety, efficacy, and pharmacokinetics of the transforming growth factor beta (TGFβ) receptor inhibitor galunisertib co-administered with the anti-programmed death-ligand 1 (PD-L1) antibody durvalumab in recurrent/refractory metastatic pancreatic cancer previously treated with ≤2 systemic regimens.

Methods

This was a two-part, single-arm, multinational, phase Ib study. In a dose-finding phase, escalating oral doses of galunisertib were co-administered on days 1–14 with fixed-dose intravenous durvalumab 1500 mg on day 1 every 4 weeks (Q4W), followed by an expansion cohort phase.

Results

The galunisertib recommended phase II dose (RP2D) when co-administered with durvalumab 1500 mg Q4W was 150 mg two times per day. No dose-limiting toxicities were recorded. Among 32 patients treated with galunisertib RP2D, 1 patient had partial response, 7 had stable disease, 15 had objective progressive disease, and 9 were not evaluable. Disease control rate was 25.0%. Median overall survival and progression-free survival were 5.72 months (95% CI: 4.01 to 8.38) and 1.87 months (95% CI: 1.58 to 3.09), respectively. Pharmacokinetic profiles for combination therapy were comparable to those published for each drug. There was no association between potential biomarkers and treatment outcomes.

Conclusion

Galunisertib 150 mg two times per day co-administered with durvalumab 1500 mg Q4W was tolerable. Clinical activity was limited. Studying this combination in patients in an earlier line of treatment or selected for predictive biomarkers of TGFβ inhibition might be a more suitable approach.

Trial registration number

ClinicalTrials.gov identifier: NCT02734160.

Prognostic Immune-Related Analysis Based on Differentially Expressed Genes in Left- and Right-Sided Colon Adenocarcinoma

Background

Colon adenocarcinoma (COAD) can be divided into left-sided and right-sided COAD (LCCs and RCCs, respectively). They have unique characteristics in various biological aspects, particularly immune invasion and prognosis. The purpose of our study was to develop a prognostic risk scoring model (PRSM) based on differentially expressed immune-related genes (IRGs) between LCCs and RCCs, therefore the prognostic key IRGs could be identified.

Methods

The gene sets and clinical information of COAD patients were derived from TCGA and GEO databases. The comparison of differentially expressed genes (DEGs) of LCCs and RCCs were conducted with appliance of “Limma” analysis. The establishment about co-expression modules of DEGs related with immune score was conducted by weighted gene co-expression network analysis (WGCNA). Furthermore, we screened the module genes and completed construction of gene pairs. The analysis of the prognosis and the establishment of PRSM were performed with univariate- and lasso-Cox regression. We employed the PRSM in the model group and verification group for the purpose of risk group assignment and PRSM accuracy verification. Finally, the identification of the prognostic key IRGs was guaranteed by the adoption of functional enrichment, “DisNor” and protein-protein interaction (PPI).

Results

A total of 215 genes were screened out by differential expression analysis and WGCNA. A PRSM with 16 immune-related gene pairs (IRGPs) was established upon the genes pairing. Furthermore, we confirmed that the risk score was an independent factor for survival by univariate- and multivariate-Cox regression. The prognosis of high-risk group in model group (P < 0.001) and validation group (P = 0.014) was significantly worse than that in low-risk group. Treg cells (P < 0.001) and macrophage M0 (P = 0.015) were highly expressed in the high-risk group. The functional analysis indicated that there was significant up-regulation with regard of lymphocyte and cytokine related terms in low-risk group. Finally, we identified five prognostic key IRGs associated with better prognosis through PPI and prognostic analysis, including IL2RB, TRIM22, CIITA, CXCL13, and CXCR6.

Conclusion

Through the analysis and screening of the DEGs between LCCs and RCCs, we constructed a PRSM which could predicate prognosis of LCCs and RCCs, and five prognostic key IRGs were identified as well. Therefore, the basis for identifying the benefits of immunotherapy and immunomodulatory was built.

Recent Advancements on Immunomodulatory Mechanisms of Resveratrol in Tumor Microenvironment

Immunomodulation of the tumor microenvironment is emerging as an important area of research for the treatment of cancer patients. Several synthetic and natural agents are being investigated for their ability to enhance the immunogenic responses of immune cells present in the tumor microenvironment to impede tumor cell growth and dissemination. Among them, resveratrol, a stilbenoid found in red grapes and many other natural sources, has been studied extensively. Importantly, resveratrol has been shown to possess activity against various human diseases, including cancer. Mechanistically, resveratrol has been shown to regulate an array of signaling pathways and processes involving oxidative stress, inflammation, apoptosis, and several anticancer effects. Furthermore, recent research suggests that resveratrol can regulate various cellular signaling events including immune cell regulation, cytokines/chemokines secretion, and the expression of several other immune-related genes. In this review, we have summarized recent findings on resveratrol’s effects on immune regulatory cells and associated signaling in various cancer types. Numerous immunomodulatory effects of resveratrol suggest it may be useful in combination with other cancer therapies including immunotherapy for effective cancer management.

Type I and II Interferons in the Anti-Tumor Immune Response

The interferons (IFNs) are essential components of the immune response against infections and malignancies. IFNs are potent promoters of the anti-tumor response, but there is also evidence that feedback mechanisms regulated by IFNs negatively control immune responses to avoid hyper-activation and limit inflammation. This balance of responses plays an important role in cancer surveillance, immunoediting and response to anticancer therapeutic approaches. Here we review the roles of both type I and type II IFNs on the control of the immune response against malignancies in the context of effects on both malignant cells and cells of the immune system in the tumor microenvironment.

Critical Roles of Balanced T Helper 9 Cells and Regulatory T Cells in Allergic Airway Inflammation and Tumor Immunity

CD4⁺T helper (Th) cells are important mediators of immune responses in asthma and cancer. When counteracted by different classes of pathogens, naïve CD4⁺T cells undergo programmed differentiation into distinct types of Th cells. Th cells orchestrate antigen-specific immune responses upon their clonal T-cell receptor (TCR) interaction with the appropriate peptide antigen presented on MHC class II molecules expressed by antigen-presenting cells (APCs). T helper 9 (Th9) cells and regulatory T (Treg) cells and their corresponding cytokines have critical roles in tumor and allergic immunity. In the context of asthma and cancer, the dynamic internal microenvironment, along with chronic inflammatory stimuli, influences development, differentiation, and function of Th9 cells and Treg cells. Furthermore, the dysregulation of the balance between Th9 cells and Treg cells might trigger aberrant immune responses, resulting in development and exacerbation of asthma and cancer. In this review, the development, differentiation, and function of Th9 cells and Treg cells, which are synergistically regulated by various factors including cytokine signals, transcriptional factors (TFs), costimulatory signals, microenvironment cues, metabolic pathways, and different signal pathways, will be discussed. In addition, we focus on the recent progress that has helped to achieve a better understanding of the roles of Th9 cells and Treg cells in allergic airway inflammation and tumor immunity. We also discuss how various factors moderate their responses in asthma and cancer. Finally, we summarize the recent findings regarding potential mechanisms for regulating the balance between Th9 and Treg cells in asthma and cancer. These advances provide opportunities for novel therapeutic strategies that are aimed at reestablishing the balance of these cells in the diseases.

Proteolysis-targeting chimera against BCL-XL destroys tumor-infiltrating regulatory T cells

Regulatory T cells (Tregs) play an important role in maintaining immune homeostasis and, within tumors, their upregulation is common and promotes an immunosuppressive microenvironment. Therapeutic strategies that can eliminate Tregs in the tumor (i.e., therapies that do not run the risk of affecting normal tissues), are urgently needed for the development of cancer immunotherapies. Here we report our discovery of B-cell lymphoma extra-large (BCL-X_L) as a potential molecular target of tumor-infiltrating (TI) Tregs. We show that pharmacological degradation of BCL-X_L using a newly developed platelet-sparing BCL-X_L Proteolysis-targeting chimera (PROTAC) induces the apoptosis of TI-Tregs and the activation of TI-CD8⁺ T cells. Moreover, these activities result in an effective suppression of syngeneic tumor growth in immunocompetent, but not in immunodeficient or CD8⁺ T cell-depleted mice. Notably, treatment with BCL-X_L PROTAC does not cause detectable damage within several normal tissues or thrombocytopenia. These findings identify BCL-X_L as a target in the elimination of TI-Tregs as a component of cancer immunotherapies, and that the BCL-X_L-specific PROTAC has the potential to be developed as a therapeutic for cancer immunotherapy.

Targeting regulatory T cells (Treg) represents a therapeutic option to abrogate tumor-associated immune suppression. Here the authors show that pharmacological degradation of BCL-X_L preferentially induces apoptosis of tumor-infiltrating Treg, promoting CD8 T cell activation and anti-tumor immune responses in preclinical cancer models.

Accelerating target deconvolution for therapeutic antibody candidates using highly parallelized genome editing

Therapeutic antibodies are transforming the treatment of cancer and autoimmune diseases. Today, a key challenge is finding antibodies against new targets. Phenotypic discovery promises to achieve this by enabling discovery of antibodies with therapeutic potential without specifying the molecular target a priori. Yet, deconvoluting the targets of phenotypically discovered antibodies remains a bottleneck; efficient deconvolution methods are needed for phenotypic discovery to reach its full potential. Here, we report a comprehensive investigation of a target deconvolution approach based on pooled CRISPR/Cas9. Applying this approach within three real-world phenotypic discovery programs, we rapidly deconvolute the targets of 38 of 39 test antibodies (97%), a success rate far higher than with existing approaches. Moreover, the approach scales well, requires much less work, and robustly identifies antibodies against the major histocompatibility complex. Our data establish CRISPR/Cas9 as a highly efficient target deconvolution approach, with immediate implications for the development of antibody-based drugs.

Efficient deconvolution of antibody targets is needed for phenotype-based discovery. Here, the authors investigate a deconvolution approach based on pooled CRISPR Cas9 to achieve 97% deconvolution success rate.

Changes in the Peripheral Blood Treg Cell Proportion in Hepatocellular Carcinoma Patients After Transarterial Chemoembolization With Microparticles

Objective

Transarterial chemoembolization (TACE) stands for an ideal therapy for patients with intermediate stage HCC. This study was carried out to observe the effect of microparticles-transarterial chemoembolization (microparticles-TACE, m-TACE) on the immune function of hepatocellular carcinoma (HCC) patients by detecting the proportion of regulatory (Treg) cells in the peripheral blood of HCC patients before and after m-TACE, and to determine whether m-TACE has a positive regulatory effect on the immune function of HCC patients.

Methods

33 HCC patients treated with Gelatn Sponge Microparticles (GSMs-TACE) were enrolled. Flow cytometry was used to determine the proportion of Treg cells and CD4+/CD8+ T cells in peripheral blood of HCC patients 1 day before GSMs-TACE, 1 to 2 weeks and 3 to 5 weeks after GSMs-TACE, respectively.

Results

The Tregs cell proportion of HCC patients was significantly higher than that of the healthy and cirrhosis controls and was associated with various clinical indicators of HCC patients. The Treg cell proportion in HCC patients with BCLC stage C was higher than that of stage B patients; The Treg cell proportion at 1 to 2 weeks postoperatively was 8.54 ± 1.27%, which was significantly lower than that before the GSMs-TACE. The Treg cell proportion at 3 to 5 weeks postoperatively was 7.59 ± 1.27%, which continued to decline. The ratio of CD4+/CD8+ T cells was 1.31 ± 0.56, 1.86 ± 0.73, 1.76 ± 0.58% (P<0.01) respectively.

Conclusion

These results indicated that m-TACE could exert a positive regulatory effect on the anticancer immune function of HCC patients, which may be used in combination with immune adjuvant therapies to enhance the efficacy of HCC.

Metabolism of Dendritic Cells in Tumor Microenvironment: For Immunotherapy

Dendritic cells (DCs) are a type of an antigen-presenting cell which undertake a job on capturing antigens coming from pathogens or tumors and presenting to T cells for immune response. The metabolism of DCs controls its development, polarization, and maturation processes and provides energy support for its functions. However, the immune activity of DCs in tumor microenvironment (TME) is inhibited generally. Abnormal metabolism of tumor cells causes metabolic changes in TME, such as hyperglycolysis, lactate and lipid accumulation, acidification, tryptophan deprivation, which limit the function of DCs and lead to the occurrence of tumor immune escape. Combined metabolic regulation with immunotherapy can strengthen the ability of antigen-presentation and T cell activation of DCs, improve the existing anti-tumor therapy, and overcome the defects of DC-related therapies in the current stage, which has great potential in oncology therapy. Therefore, we reviewed the glucose, lipid, and amino acid metabolism of DCs, as well as the metabolic changes after being affected by TME. Together with the potential metabolic targets of DCs, possible anti-tumor therapeutic pathways were summarized.

Interleukin-10: A double-edged sword in breast cancer

Breast cancer (BC) is a frequently diagnosed cancer among women worldwide. Currently, BC can be divided into different subgroups according to the presence of the following hormone receptors: estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Each of these subgroups has different treatment strategies. However, the presence of new metastatic lesions and patient deterioration suggest resistance to a given treatment. Various lines of evidence had shown that cytokines are one of the important mediators of tumor growth, invasion, metastasis, and treatment resistance. Interleukin-10 (IL-10) is an immunoregulatory cytokine, and acts as a poor prognostic marker in many cancers. The anti-inflammatory IL-10 blocks certain effects of inflammatory cytokines. It also antagonizes the co-stimulatory molecules on the antigen-presenting cells. Here, we review the current knowledge on the function and molecular mechanism of IL-10, and recent findings on how IL-10 contributes to the progression of BC.

CCR4, CCR8, and P2RY14 as Prognostic Factors in Head and Neck Squamous Cell Carcinoma Are Involved in the Remodeling of the Tumor Microenvironment

The tumor microenvironment (TME) plays a critical role in the initiation and progression of cancer. However, the specific mechanism of its regulation in head and neck squamous cell carcinoma (HNSCC) remains unclear. In this study, we first applied the ESTIMATE method to calculate the immune and stromal scores in patients’ tumor tissues from The Cancer Genome Atlas (TCGA) database. GSE41613, GSE30784, and GSE37991 data sets from the Gene Expression Omnibus (GEO) database were recruited for further validation. Differentially expressed genes (DEGs) were identified and then analyzed by Cox regression analysis and protein-protein interaction (PPI) network construction. DEGs significantly associated with prognosis and TME will be identified as hub genes. These genes were also validated at the protein level by immunohistochemical analysis of 10 pairs of primary tumor tissues and the adjacent normal tissues from our institution. The relationship between hub genes expression and immune cell fraction estimated by CIBERSORT software was also examined. 275 DEGs were significantly associated with TME. CCR4, CCR8, and P2RY14 have then identified as hub genes by intersection Cox and PPI analysis. Further investigation revealed that the expression of CCR4, CCR8, and P2RY14 was negatively correlated with clinicopathological characteristics (clinical stage, T stage) and positively associated with survival in HNSCC patients, especially in male patients. The expression of CCR8 and P2RY14 was lower in males than in females. CCR8 and P2RY14 were differentially expressed in tumor tissues than normal tissues, and the results were validated at the protein level by immunohistochemistry experiments. Gene set enrichment analysis (GSEA) showed that the high expression groups’ hub genes were mainly enriched for immune-related activities. In the low-expression groups, genes were primarily enriched in metabolic pathways. CIBERSORT results showed that the expression of these genes was all negatively correlated with the fraction of memory B cells and positively correlated with the fraction of the other four cells, including naive B cells, resting T cells CD4 memory, T cells follicular helper, and T cells regulatory (Tregs). The results suggest that CCR4, CCR8, and P2RY14 may be responsible for maintaining the immune dominance of TME, thus leading to a better prognosis.

Advantages of targeting the tumor immune microenvironment over blocking immune checkpoint in cancer immunotherapy

Despite great success in cancer immunotherapy, immune checkpoint-targeting drugs are not the most popular weapon in the armory of cancer therapy. Accumulating evidence suggests that the tumor immune microenvironment plays a critical role in anti-cancer immunity, which may result in immune checkpoint blockade therapy being ineffective, in addition to other novel immunotherapies in cancer patients. In the present review, we discuss the deficiencies of current cancer immunotherapies. More importantly, we highlight the critical role of tumor immune microenvironment regulators in tumor immune surveillance, immunological evasion, and the potential for their further translation into clinical practice. Based on their general targetability in clinical therapy, we believe that tumor immune microenvironment regulators are promising cancer immunotherapeutic targets. Targeting the tumor immune microenvironment, alone or in combination with immune checkpoint-targeting drugs, might benefit cancer patients in the future.

Mycomedicine: A Unique Class of Natural Products with Potent Anti-tumour Bioactivities

Mycomedicine is a unique class of natural medicine that has been widely used in Asian countries for thousands of years. Modern mycomedicine consists of fruiting bodies, spores, or other tissues of medicinal fungi, as well as bioactive components extracted from them, including polysaccharides and, triterpenoids, etc. Since the discovery of the famous fungal extract, penicillin, by Alexander Fleming in the late 19th century, researchers have realised the significant antibiotic and other medicinal values of fungal extracts. As medicinal fungi and fungal metabolites can induce apoptosis or autophagy, enhance the immune response, and reduce metastatic potential, several types of mushrooms, such as Ganoderma lucidum and Grifola frondosa, have been extensively investigated, and anti-cancer drugs have been developed from their extracts. Although some studies have highlighted the anti-cancer properties of a single, specific mushroom, only limited reviews have summarised diverse medicinal fungi as mycomedicine. In this review, we not only list the structures and functions of pharmaceutically active components isolated from mycomedicine, but also summarise the mechanisms underlying the potent bioactivities of several representative mushrooms in the Kingdom Fungi against various types of tumour.

Extracellular vesicles and the regulation of tumor immunity: Current progress and future directions

As nano-level information carriers, extracellular vesicles (EVs) contain proteins, DNA or RNA, which maintain the transmembrane transport of biomolecules and the homeostasis of normal cells. EVs can be released by most cell types and absorbed by specific recipient cells, subsequently affecting phenotypic expression. EVs are believed to play an important role in cellular communication, especially in immune cells. During tumor development, EVs of different origins have different effects on the survival and growth of tumor cells. Some tumor cell-derived EVs can mediate tumor immunosuppressive responses by inhibiting the differentiation and maturation of dendritic cells (DCs) and by negatively regulating the expression of T cell receptors, causing tumor cells to escape immune surveillance and proliferate. EVs have therefore become a key component of tumor cell proliferation and metastasis. In contrast, EVs derived from DCs mediate antitumor immune activation by inducing the killing and inhibitory effects of the immune system. This makes it an antigen component of the antitumor response. Integrating the interaction and connection of EVs to immunosuppression and immune response is significant for the application of EVs in clinical practice. Here, we reviewed the research progress on the role of EVs in the immune regulation of tumors.

Smad7 suppresses melanoma lung metastasis by impairing Tregs migration to the tumor microenvironment

Transforming growth factor β (TGF-β) signaling plays critical roles in both physiological and pathological conditions. In the tumor microenvironment, TGF-β are well demonstrated as a tumor inducer, which also promote tumor growth and metastasis. SMAD family is an important TGF-β signalling transducer, which consists of receptor-regulated SMADs (R-SMADs), common-mediator SMADs (co-SMADs), and inhibitory SMADs (I-SMADs). Smad7 is one of the I-SMADs which has been proved to block TGF-β signalling transduction in both tumor cells and immune cells. Accumulated evidence has suggested SMAD7 acted as a tumor suppressor in various cancer types, such as colorectal cancer, pancreatic cancer and skin melanoma, etc. However, the role of SMAD7 in melanoma lung metastasis has not been well studied. Here, we first investigated the role of SMAD7 on tumor cell viability by overexpressing SMAD7 in murine melanoma cell line B16-F10. Our results showed that SMAD7 overexpression slightly impaired B16-F10 cells growth, promoted cell apoptosis and arrested the cell cycle at S phase. In vivo study showed that SMAD7 overexpression inhibited B16-F10 lung metastasis. Further mechanism study suggested that SMAD7 promoted T cells activation by decreasing regulatory T cells (Tregs) infiltrating into the tumor microenvironment. In summary, our results proved that tumor cell derived SMAD7 inhibited melanoma lung metastasis by impairing the migration capacity of Tregs.

The Distinctive Serum Metabolomes of Gastric, Esophageal and Colorectal Cancers

Simple Summary

Cancer of the stomach, esophagus and colon are often fatal. Ways are being sought to establish patient-friendly screening tests that would allow these cancers to be detected earlier. Examination of the metabolomics results of cancer patient’s serum for certain metabolites unique for a particular cancer was the goal of this review. From studies conducted within the past five years several metabolites were found to be changed in cancer compared to non-cancer patients for each of the three cancers. Further confirmation of what was discovered in this review coupled with establishment of standard protocols may allow for cancer screening on patient blood samples to become routine clinical tests.

Abstract

Three of the most lethal cancers in the world are the gastrointestinal cancers—gastric (GC), esophageal (EC) and colorectal cancer (CRC)—which are ranked as third, sixth and fourth in cancer deaths globally. Early detection of these cancers is difficult, and a quest is currently on to find non-invasive screening tests to detect these cancers. The reprogramming of energy metabolism is a hallmark of cancer, notably, an increased dependence on aerobic glycolysis which is often referred to as the Warburg effect. This metabolic change results in a unique metabolic profile that distinguishes cancer cells from normal cells. Serum metabolomics analyses allow one to measure the end products of both host and microbiota metabolism present at the time of sample collection. It is a non-invasive procedure requiring only blood collection which encourages greater patient compliance to have more frequent screenings for cancer. In the following review we will examine some of the most current serum metabolomics studies in order to compare their results and test a hypothesis that different tumors, notably, from EC, GC and CRC, have distinguishing serum metabolite profiles.

Metabolic reprogramming of T regulatory cells in the hypoxic tumor microenvironment

Metabolic dysregulation in the hypoxic tumor microenvironment (TME) is considered as a hallmark of solid tumors, leading to changes in biosynthetic pathways favoring onset, survival and proliferation of malignant cells. Within the TME, hypoxic milieu favors metabolic reprogramming of tumor cells, which subsequently affects biological properties of tumor-infiltrating immune cells. T regulatory cells (Tregs), including both circulating and tissue-resident cells, are particularly susceptible to hypoxic metabolic signaling that can reprogram their biological and physicochemical properties. Furthermore, metabolic reprogramming modifies Tregs to utilize alternative substrates and undergo a plethora of metabolic events to meet their energy demands. Major impact of this metabolic reprogramming can result in differentiation, survival, excessive secretion of immunosuppressive cytokines and proliferation of Tregs within the TME, which in turn dampen anti-tumor immune responses. Studies on fine-tuning of Treg metabolism are challenging due to heterogenicity of tissue-resident Tregs and their dynamic functions. In this review, we highlight tumor intrinsic and extrinsic factors, which can influence Treg metabolism in the hypoxic TME. Moreover, we focus on metabolic reprogramming of Tregs that could unveil potential regulatory networks favoring tumorigenesis/progression, and provide novel insights, including inhibitors against acetyl-coA carboxylase 1 and transforming growth factor beta into targeting Treg metabolism for therapeutic benefits.

Tumour heterogeneity and intercellular networks of nasopharyngeal carcinoma at single cell resolution

The heterogeneous nature of tumour microenvironment (TME) underlying diverse treatment responses remains unclear in nasopharyngeal carcinoma (NPC). Here, we profile 176,447 cells from 10 NPC tumour-blood pairs, using single-cell transcriptome coupled with T cell receptor sequencing. Our analyses reveal 53 cell subtypes, including tumour-infiltrating CD8+ T, regulatory T (Treg), and dendritic cells (DCs), as well as malignant cells with different Epstein-Barr virus infection status. Trajectory analyses reveal exhausted CD8+ T and immune-suppressive TNFRSF4+ Treg cells in tumours might derive from peripheral CX3CR1+CD8+ T and naïve Treg cells, respectively. Moreover, we identify immune-regulatory and tolerogenic LAMP3+ DCs. Noteworthily, we observe intensive inter-cell interactions among LAMP3+ DCs, Treg, exhausted CD8+ T, and malignant cells, suggesting potential cross-talks to foster an immune-suppressive niche for the TME. Collectively, our study uncovers the heterogeneity and interacting molecules of the TME in NPC at single-cell resolution, which provide insights into the mechanisms underlying NPC progression and the development of precise therapies for NPC.

The role of FOXP3 rs3761548 and rs2294021 polymorphisms in pediatrics acute lymphoblastic leukemia: association with risk and response to therapy

FOXP3 X-linked gene has crucial roles in the development and function of regulatory T cells. We investigated the association of FOXP3 rs3761548, rs3761549 and rs2294021 single nucleotide polymorphisms (SNPs) with acute lymphoblastic leukemia (ALL) susceptibility and response to therapy. Genotyping was performed in 247 patients and 210 healthy subjects. We observed a higher frequency of rs3761548 A carriers and rs2294021 C carriers (p < 0.04) in male patients, and lower frequencies of rs3761548 AC genotype (p = 0.04) and rs2294021 CT genotype (p = 0.01) in female patients compared to controls. ACC (p = 0.04) and ATC haplotypes (p = 0.002) were associated with susceptibility to ALL. There was a significant correlation between the genotypes of rs3761548 and rs2294021 SNPs with event-free survival (EFS) and overall survival (OS). The rs3761548 A genotype in male patients was associated with increased risk of relapse (p < 0.0001), shorter EFS, increased death rate (p = 0.002) and shorter OS compared to C genotype (p = 0.001). Similar significant results were observed for the relation of rs2294021 C genotype with response to therapy in male patients. In females, patients with rs3761548 AC genotype had longer EFS (p = 0.02) and those with rs2294021 CT had longer EFS and OS (p < 0.005). According to haplotype analysis, patients carrying ACC or ATC haplotypes had the highest number of WBCs and shorter EFS or OS, and patients with CCT haplotype had the lowest number of WBCs and longer EFS or OS. These results provided evidence for the impact of these polymorphisms on susceptibility and response to therapy in children with ALL.

The role of regulatory T cells in the pathogenesis and treatment of prostate cancer

Despite developments in the treatment of various cancers, prostate cancer is one of the deadliest diseases known to men. Systemic therapies such as androgen deprivation, chemotherapy, and radiation therapy have not been very successful in treating this disease. Numerous studies have shown that there is a direct relationship between cancer progression and inhibition of anti-tumor immune responses that can lead to progression of various malignancies, including prostate cancer. Interestingly, CD4⁺CD25⁺FoxP3⁺ regulatory T cells significantly accumulate and increase in draining lymph nodes and PBMCs of patients with prostate cancer and other solid tumors. In vivo and in vitro studies have shown that Tregs can suppress anti-tumor responses, which is directly related to the increased risk of cancer recurrence. Tregs are essential for preserving self-tolerance and inhibiting extra immune responses harmful to the host. Since the tumor-related antigens are mainly self-antigens, Tregs could play a major role in tumor progression. Accordingly, it has discovered that prostate cancer patients with higher Tregs have poor prognosis and low survival rates. However, anti-tumor responses can be reinforced by suppression of Tregs with using monoclonal antibodies against CD25 and CTLA-4. Therefore, depleting Tregs or suppressing their functions could be one of the effective ways for prostate cancer immunotherapy. The purpose of this review is to investigate the role of Treg cells in the progression of prostate cancer and to evaluate effective strategies for the treatment of prostate cancer by regulating Treg cells.

Tumor microenvironment and immune-related therapies of head and neck squamous cell carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are a type of common malignant tumor, mainly manifesting as oropharyngeal, oral cavity, laryngopharyngeal, hypopharyngeal, and laryngeal cancers. These highly aggressive malignant tumors reportedly affect more than 830,000 patients worldwide every year. Currently, the main treatments for HNSCC include surgery, radiotherapy, chemotherapy, and immunotherapy, as well as combination therapy. However, the overall 5-year survival rate of HNSCC has remained 50%, and it has not significantly improved in the past 10 years. Previous studies have shown that the tumor microenvironment (TME) plays a crucial role in the recurrence, metastasis, and drug resistance of patients with HNSCC. In this review, we summarize the role of anti-tumor and pro-tumor immune cells, as well as extracellular components in the TME of HNSCC. We also discuss classical HNSCC immunotherapy and highlight examples of clinical trials using CTLA-4 inhibitors and programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1)-related combination therapies. We also outline some molecules in the TME known to regulate immunosuppressive cells. Furthermore, the role and underlying mechanism of radiation therapy on the TME, immune cells, and immune response are discussed.

CAR19/22 T cell therapy in adult refractory Burkitt's lymphoma

The treatment of refractory Burkitt's lymphoma (BL) is still a challenge. Although CAR-T cell therapy has achieved good responses in diffuse large B cell lymphoma, there is no case series report about the efficacy of CAR-T cell therapy in adult Burkitt's lymphoma. In this study, we evaluate the efficacy and safety of CAR19/22 T cell therapy in six refractory Burkitt's lymphoma cases with poor genetic prognostic factors. After CAR-T cell therapy, five cases had grade 1 and one had grade 3 cytokine release syndrome. Three patients achieved an objective response (3/6 50%), including two partial remission and one complete remission. One CR patient received allogeneic hematopoietic stem cell transplantation (HSCT) and one PR patient received CAR22/19-T cells following auto-HSCT, and they were still in remission at 37 and 22 months of follow-up, respectively. Interestingly, patients with bulky disease (case 2, 4 and 5) had higher levels of serum IL-2R, which was secreted by regulatory T cells, lower CAR lentiviral amplification and poorer prognosis with shorter survival time than cases with non-bulky disease. It is suggested that high tumor burden, more immune suppressive cells and limited CAR-T cell expansion might affect the efficacy of CAR-T cell therapy. CAR-T cell therapy in adult BL patients whose best response cannot achieve CR may need to bridge to other treatments (such as HSCT) early.

Mining The Cancer Genome Atlas database for tumor mutation burden and its clinical implications in gastric cancer

BACKGROUND

Tumor mutational burden (TMB) is an important independent biomarker for the response to immunotherapy in multiple cancers. However, the clinical implications of TMB in gastric cancer (GC) have not been fully elucidated.

AIM

To explore the landscape of mutation profiles and determine the correlation between TMB and microRNA (miRNA) expression in GC.

METHODS

Genomic, transcriptomic, and clinical data from The Cancer Genome Atlas were used to obtain mutational profiles and investigate the statistical correlation between mutational burden and the overall survival of GC patients. The difference in immune infiltration between high- and low-TMB subgroups was evaluated by Wilcoxon rank-sum test. Furthermore, miRNAs differentially expressed between the high- and low-TMB subgroups were identified and the least absolute shrinkage and selection operator method was employed to construct a miRNA-based signature for TMB prediction. The biological functions of the predictive miRNAs were identified with DIANA-miRPath v3.0.

RESULTS

C>T single nucleotide mutations exhibited the highest mutation incidence, and the top three mutated genes were TTN, TP53, and MUC16 in GC. High TMB values (top 20%) were markedly correlated with better survival outcome, and multivariable regression analysis indicated that TMB remained prognostic independent of TNM stage, histological grade, age, and gender. Different TMB levels exhibited different immune infiltration patterns. Significant differences between the high- and low-TMB subgroups were observed in the infiltration of CD8+ T cells, M1 macrophages, regulatory T cells, and CD4+ T cells. In addition, we developed a miRNA-based signature using 23 differentially expressed miRNAs to predict TMB values of GC patients. The predictive performance of the signature was confirmed in the testing and the whole set. Receiver operating characteristic curve analysis demonstrated the optimal performance of the signature. Finally, enrichment analysis demonstrated that the set of miRNAs was significantly enriched in many key cancer and immune-related pathways.

CONCLUSION

TMB

The Therapeutic Potential of Regulatory T Cells: Challenges and Opportunities

Regulatory T cells (Tregs) are an immunosuppressive subgroup of CD4+ T cells which are identified by the expression of forkhead box protein P3 (Foxp3). The modulation capacity of these immune cells holds an important role in both transplantation and the development of autoimmune diseases. These cells are the main mediators of self-tolerance and are essential for avoiding excessive immune reactions. Tregs play a key role in the induction of peripheral tolerance that can prevent autoimmunity, by protecting self-reactive lymphocytes from the immune reaction. In contrast to autoimmune responses, tumor cells exploit Tregs in order to prevent immune cell recognition and anti-tumor immune response during the carcinogenesis process. Recently, numerous studies have focused on unraveling the biological functions and principles of Tregs and their primary suppressive mechanisms. Due to the promising and outstanding results, Tregs have been widely investigated as an alternative tool in preventing graft rejection and treating autoimmune diseases. On the other hand, targeting Tregs for the purpose of improving cancer immunotherapy is being intensively evaluated as a desirable and effective method. The purpose of this review is to point out the characteristic function and therapeutic potential of Tregs in regulatory immune mechanisms in transplantation tolerance, autoimmune diseases, cancer therapy, and also to discuss that how the manipulation of these mechanisms may increase the therapeutic options.

Hematopoietic versus Solid Cancers and T Cell Dysfunction: Looking for Similarities and Distinctions

Simple Summary

Dysfunction of the immune T cell compartment occurs in many hematopoietic as well as solid cancers and hampers successful application of new immunotherapeutic approaches. A complete understanding of T cell dysfunction might improve the outcome of such therapies, but an overview in the various cancers is still lacking. We aim to map areas of similarities and differences in solid versus hematopoietic malignancies, providing a high-level rather than a detailed perspective on T cell dysfunction in those tumors.

Abstract

Cancer cells escape, suppress and exploit the host immune system to sustain themselves, and the tumor microenvironment (TME) actively dampens T cell function by various mechanisms. Over the last years, new immunotherapeutic approaches, such as adoptive chimeric antigen receptor (CAR) T cell therapy and immune checkpoint inhibitors, have been successfully applied for refractory malignancies that could only be treated in a palliative manner previously. Engaging the anti-tumor activity of the immune system, including CAR T cell therapy to target the CD19 B cell antigen, proved to be effective in acute lymphocytic leukemia. In low-grade hematopoietic B cell malignancies, such as chronic lymphocytic leukemia, clinical outcomes have been tempered by cancer-induced T cell dysfunction characterized in part by a state of metabolic lethargy. In multiple myeloma, novel antigens such as BCMA and CD38 are being explored for CAR T cells. In solid cancers, T cell-based immunotherapies have been applied successfully to melanoma and lung cancers, whereas application in e.g., breast cancer lags behind and is modestly effective as yet. The main hurdles for CAR T cell immunotherapy in solid tumors are the lack of suitable antigens, anatomical inaccessibility, and T cell anergy due to immunosuppressive TME. Given the wide range of success and failure of immunotherapies in various cancer types, it is crucial to comprehend the underlying similarities and distinctions in T cell dysfunction. Hence, this review aims at comparing selected, distinct B cell-derived versus solid cancer types and at describing means by which malignant cells and TME might dampen T cell anti-tumor activity, with special focus on immunometabolism. Drawing a meaningful parallel between the efficacy of immunotherapy and the extent of T cell dysfunction will shed light on areas where we can improve immune function to battle cancer.

Regulatory T Cells in the Tumor Microenvironment

Regulatory T cells (T_regs) are an immunosuppressive subpopulation of CD4⁺ T cells that are endowed with potent suppressive activity and function to limit immune activation and maintain homeostasis. These cells are identified by the hallmark transcription factor FOXP3 and the high-affinity interleukin-2 (IL-2) receptor chain CD25. T_regs can be recruited to and persist within the tumor microenvironment (TME), acting as a potent barrier to effective antitumor immunity. This chapter will discuss [i] the history and hallmarks of T_regs; [ii] the recruitment, development, and persistence of T_regs within the TME; [iii] T_reg function within TME; asnd [iv] the therapeutic targeting of T_regs in the clinic. This chapter will conclude with a discussion of likely trends and future directions.

Exosomes in Immune Regulation

Exosomes, small extracellular vesicles mediate intercellular communication by transferring their cargo including DNA, RNA, proteins and lipids from cell to cell. Notably, in the immune system, they have protective functions. However in cancer, exosomes acquire new, immunosuppressive properties that cause the dysregulation of immune cells and immune escape of tumor cells supporting cancer progression and metastasis. Therefore, current investigations focus on the regulation of exosome levels for immunotherapeutic interventions. In this review, we discuss the role of exosomes in immunomodulation of lymphoid and myeloid cells, and their use as immune stimulatory agents to elicit specific cytotoxic responses against the tumor.

Cytokine-chemokine network driven metastasis in esophageal cancer; promising avenue for targeted therapy

Esophageal cancer (EC) is a disease often marked by aggressive growth and poor prognosis. Lack of targeted therapies, resistance to chemoradiation therapy, and distant metastases among patients with advanced disease account for the high mortality rate. The tumor microenvironment (TME) contains several cell types, including fibroblasts, immune cells, adipocytes, stromal proteins, and growth factors, which play a significant role in supporting the growth and aggressive behavior of cancer cells. The complex and dynamic interactions of the secreted cytokines, chemokines, growth factors, and their receptors mediate chronic inflammation and immunosuppressive TME favoring tumor progression, metastasis, and decreased response to therapy. The molecular changes in the TME are used as biological markers for diagnosis, prognosis, and response to treatment in patients. This review highlighted the novel insights into the understanding and functional impact of deregulated cytokines and chemokines in imparting aggressive EC, stressing the nature and therapeutic consequences of the cytokine-chemokine network. We also discuss cytokine-chemokine oncogenic potential by contributing to the Epithelial-Mesenchymal Transition (EMT), angiogenesis, immunosuppression, metastatic niche, and therapeutic resistance development. In addition, it discusses the wide range of changes and intracellular signaling pathways that occur in the TME. Overall, this is a relatively unexplored field that could provide crucial insights into tumor immunology and encourage the effective application of modulatory cytokine-chemokine therapy to EC.

B7-H3×4-1BB bispecific antibody augments antitumor immunity by enhancing terminally differentiated CD8+ tumor-infiltrating lymphocytes

Cancer immunotherapy with 4-1BB agonists has limited further clinical development because of dose-limiting toxicity. Here, we developed a bispecific antibody (bsAb; B7-H3×4-1BB), targeting human B7-H3 (hB7-H3) and mouse or human 4-1BB, to restrict the 4-1BB stimulation in tumors. B7-H3×m4-1BB elicited a 4-1BB-dependent antitumor response in hB7-H3-overexpressing tumor models without systemic toxicity. BsAb primarily targets CD8 T cells in the tumor and increases their proliferation and cytokine production. Among the CD8 T cell population in the tumor, 4-1BB is solely expressed on PD-1⁺Tim-3⁺ "terminally differentiated" subset, and bsAb potentiates these cells for eliminating the tumor. Furthermore, the combination of bsAb and PD-1 blockade synergistically inhibits tumor growth accompanied by further increasing terminally differentiated CD8 T cells. B7-H3×h4-1BB also shows antitumor activity in h4-1BB-expressing mice. Our data suggest that B7-H3×4-1BB is an effective and safe therapeutic agent against B7-H3-positive cancers as monotherapy and combination therapy with PD-1 blockade.

Long-term aspirin intervention can inhibit TIGIT, regulating T cells to reverse damage to intestines

Aspirin is one of the most commonly prescribed medications. Evidence shows that it can even treat and prevent intestinal tumors. However, it has also caused a great deal of controversy due to its intestinal side effects. We therefore explored whether aspirin was beneficial or harmful to the intestines. We used aspirin continuously interfered with C57BL/6 J mice for 48 weeks, examining their intestinal tissues at 13, 26 and 48 weeks to determine the drug's effect on the intestines. In addition, we used flow cytometry (FCM) used to detect T cells and expression of T-cell immunoreceptor with immunoglobulin (Ig)- and tyrosine-based inhibitory motif (ITIM) domain (TIGIT) on their surfaces to determine aspirin's immunomodulatory effects. The results showed that long-term aspirin intervention could reverse damage to the intestines, an effect related to the drug's significant inhibitory effect on TIGIT. The change in TIGIT level could regulate T-cell subsets, so that counts of Cluster of Differentiation 4 (CD4)+/chemokine (C-X3-C motif) receptor 3 (CXCR3)+ T-helper 1 (Th1) cells and CD4+/interleukin-4 (IL-4)+ Th2 cells increased, while those of CD4+/C-C chemokine receptor type 6 (CCR6)+ Th17 cells and CD4+/CD25+ regulatory T cells (Tregs) decreased. In summary, we demonstrated that long-term aspirin intervention could inhibit TIGIT, regulating T cells to reverse damage to the intestines. Furthermore, aspirin is a potential therapy for diseases related to an increase in TIGIT.

Unfavorable impact of decreased muscle quality on the efficacy of immunotherapy for advanced non-small cell lung cancer

BACKGROUND

Quantitative skeletal muscle mass loss has the potential to predict the therapeutic effects of immune checkpoint inhibitors. This study aimed to assess the impact of muscular quality on the abovementioned outcomes.

METHODS

This study retrospectively reviewed the medical records of patients with advanced non-small cell lung cancer (NSCLC) who had received PD-1/PD-L1 inhibitor monotherapy between March 2016 and February 2018. High muscle quality was stipulated as a skeletal muscle density ≥41 and ≥33 Hounsfield units in patients with a body mass index (BMI) <25 kg/m2 and ≥25 kg/m2 , respectively, as assessed using lumbar computed tomography images. High muscle quantity was stipulated as a lumbar skeletal muscle index ≥41 cm2 /m2 in women, ≥43 cm2 /m2 in men with a BMI <25 kg/m2 , and ≥53 cm2 /m2 in men with a BMI ≥25 kg/m2 . We evaluated the associations of these muscular parameters with the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

Out of 156 patients, 80 (51.3%) and 47 (30.1%) showed low muscle quality and quantity, respectively. Patients with high muscle quality showed higher ORR (35.0 vs. 15.8 %, p<0.05) and longer PFS durations (median, 4.5 vs. 2.0 months, p<0.05) than those with low muscle quality. There were no noted differences in the ORR or PFS between patients with high and those with low muscle quantities. On the contrary, regardless of muscle quality and quantity, there were no differences in OS between patients with high and those with low muscle status.

CONCLUSIONS

Lumbar skeletal muscle quality has the potential to predict the therapeutic effect of anti-programed cell death 1/programed cell death ligand 1 inhibitor monotherapy in patients with advanced NSCLC.

Tumor-infiltrating T-regulatory cells adapt to altered metabolism to promote tumor-immune escape

Tumor mass and its microenvironment alter host immune system in various ways to promote tumor growth. One of the modifications is evasion of immune surveillance by augmenting the number of Tregs in tumor vicinity. Elevated levels of Tregs are seen in peripheral circulation and tumor tissue of cancer patients. Cancer cells release several chemokines to attract Tregs in tumor-site. Infiltration of Tregs has clinical significance because being immunosuppressive infiltrating Tregs suppress other immune cells making the tumor microenvironment favorable for tumor growth. On the other hand, infiltrating Tregs show metabolic alteration in tumor microenvironment which allows their selective survival over the others. Persistence of Tregs in the tumor microenvironment and subsequent immunosuppression makes Tregs a potential therapeutic obstacle and the reason behind the failure of immunotherapy. In this review, we emphasize the recent development in the metabolic adaptation of tumor-infiltrating Tregs and the therapeutic approaches to boost immunity against cancer.

Indoleamine 2,3-Dioxygenase Activity-Induced Acceleration of Tumor Growth, and Protein Kinases-Related Novel Therapeutics Regimens

Indoleamine 2,3-dioxygenase (IDO) is overexpressed in response to interferon-gamma (IFN-γ). IDO-mediated degradation of tryptophan (Trp) along the kynurenine (Kyn) pathway by immune cells is associated with the anti-microbial, and anti-tumor defense mechanisms. In contrast, IDO is constitutively expressed by various tumors and creates an immunosuppressive microenvironment around the tumor tissue both by depletion of the essential amino acid Trp and by formation of Kyn, which is immunosuppressive metabolite of Trp. IDO may activate its own expression in human cancer cells via an autocrine aryl hydrocarbon receptor (AhR)- interleukin 6 (IL-6)-signal transducer and activator of transcription 3 (STAT3) signaling loop. Although IDO is not a unique marker, in many clinical trials serum IDO activity is suggested to be an important parameter in the pathogenesis of cancer development and growth. Measuring IDO activity in serum seems to be an indicator of cancer growth rate, however, it is controversial whether this approach can be used as a reliable guide in cancer patients treated with IDO inhibitors. Thus, IDO immunostaining is strongly recommended for the identification of higher IDO producing tumors, and IDO inhibitors should be included in post-operative complementary therapy in IDO positive cancer cases only. Novel therapies that target the IDO pathway cover checkpoint protein kinases related combination regimens. Currently, multi-modal therapies combining IDO inhibitors and checkpoint kinase blockers in addition to T regulatory (Treg) cell-modifying treatments seem promising.

Peptides that immunoactivate the tumor microenvironment

Cancer immunotherapy has achieved positive clinical outcomes and is revolutionizing cancer treatment. However, cancer immunotherapy has thus far failed to improve outcomes for most "cold tumors", which are characterized by low infiltration of immune cells and immunosuppressive tumor microenvironment. Enhancing the responsiveness of cold tumors to cancer immunotherapy by stimulating the components of the tumor microenvironment is a strategy pursued in the last decade. Currently, most of the agents used to modify the tumor microenvironment are small molecules or antibodies. Small molecules exhibit low affinity and specificity towards the target and antibodies have shortcomings such as poor tissue penetration and high production cost. Peptides may overcome these drawbacks and therefore are promising materials for immunomodulating agents. Here we systematically summarize the currently developed immunoactivating peptides and discuss the potential of peptide therapeutics in cancer immunology.

Regulatory T cell targeting in cancer: Emerging strategies in immunotherapy

The adaptive immune system is modulated by an important subset of CD4⁺ T lymphocytes called Treg cells that function in maintaining immune homeostasis by preventing excessive immune activation. Both deficiency and overactivation of Treg cell function can result in disease pathology. While loss of Treg function can lead to autoimmunity, an overabundance of Treg activity can promote tumorigenesis. Blocking and/or depleting Tregs has emerged as a viable strategy to enhance antitumor immunity. A major limitation underlying the limited efficacy observed with Treg therapies in the clinic is lack of selective targeting, often attributed to concurrent depletion of antitumor effector T-cell populations. Novel approaches to improve the specificity of Treg targeting in the context of cancer include the use of T-cell receptor mimic antibodies, bispecific antibodies, and near-infrared photoimmunotherapy. Next-generation technology platforms and transcriptomic/computational-based screening methods have been recently developed to identify preferential Treg targets. Herein, we highlight key advancements and challenges pertaining to the development of novel Treg targeting cancer therapeutics and discuss ongoing clinical trials evaluating next-generation Treg therapies for solid tumors.