Interleukin 10 in the tumor microenvironment: a target for anticancer immunotherapy

Integrative Analysis of Complement System to Prognosis and Immune Infiltrating in Colon Cancer and Gastric Cancer

Background

The complement system acts as an integral part of the innate immune response, which acts primarily to remove pathogens and injured cells. Emerging evidence has shown the activation of the immune regulatory function of complements in the tumor microenvironment (TME). We revealed the expression levels of various complements in human cancers and their role in tumor prognosis and immune infiltration.

Methods

The differential expression of complements was explored via the Tumor Immune Estimation Resource (TIMER) site and the Oncomine database. To investigate whether these differentially expressed complements have correlation with the prognosis of gastric cancer (GC) and colon cancer, their impact on survival was assessed using the PrognoScan database and Kaplan-Meier plotter. The correlations between complements and tumor immune-infiltrating levels and immune gene markers were statistically explored in TIMER based on Spearman's correlation coefficients and p-values.

Results

In two colon cancer cohorts, an increased expression level of DAF (CD55) has statistically significant correlation with poor disease-free survival (DFS). High C3, CR4, and C5aR1 expression levels were significantly related with poor prognosis in GC patients. In addition, C3, CR4, and C5aR1 expression was positively related to the tumor purity and infiltration levels of multiple immune cells in stomach adenocarcinoma (STAD). Moreover, the expression levels of C3, CR4, and C5aR1 were also strongly correlated with various immune marker sets, such as those of tumor-associated macrophages (TAMs), M1 and M2 macrophages, T cell exhaustion, Tregs, and DCs, in STAD. Additionally, CD55 has positive correlation with few immune cell infiltration levels in colon adenocarcinoma (COAD), but its correlation with immune marker sets was not statistically significant.

Conclusion

These findings confirm the relationship between various complements and tumor prognosis and immune infiltration in colon cancer and GC. CD55 may serve as an indicator on the survival prognosis of patients with colon cancer. Furthermore, as biomarkers for poor prognosis in GC, complements C3, CR4, and C5aR1 may provide potential biological targets for GC immunotherapy.

Mechanisms Governing Immunotherapy Resistance in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is a lethal malignancy with an overall 5-year survival rate of 10%. Disease lethality is due to late diagnosis, early metastasis and resistance to therapy, including immunotherapy. PDA creates a robust fibroinflammatory tumor microenvironment that contributes to immunotherapy resistance. While previously considered an immune privileged site, evidence demonstrates that in some cases tumor antigen-specific T cells infiltrate and preferentially accumulate in PDA and are central to tumor cell clearance and long-term remission. Nonetheless, PDA can rapidly evade an adaptive immune response using a myriad of mechanisms. Mounting evidence indicates PDA interferes with T cell differentiation into potent cytolytic effector T cells via deficiencies in naive T cell priming, inducing T cell suppression or promoting T cell exhaustion. Mechanistic research indicates that immunotherapy combinations that change the suppressive tumor microenvironment while engaging antigen-specific T cells is required for treatment of advanced disease. This review focuses on recent advances in understanding mechanisms limiting T cell function and current strategies to overcome immunotherapy resistance in PDA.

IL-10 Signaling in the Tumor Microenvironment of Ovarian Cancer

Unlike other malignancies, ovarian cancer (OC) creates a complex tumor microenvironment with distinctive peritoneal ascites consisting of a mixture of several immunosuppressive cells which impair the ability of the patient's immune system to fight the disease. The poor survival rates observed in advanced stage OC patients and the lack of effective conventional therapeutic options have been attributed in large part to the immature dendritic cells (DCs), IL-10 secreting regulatory T cells, tumor-associated macrophages, myeloid-derived suppressor cells, and cancer stem cells that secrete inhibitory cytokines. This review highlights the critical role played by the intraperitoneal presence of IL-10 in the generation of an immunosuppressive tumor microenvironment. Further, the effect of antibody neutralization of IL-10 on the efficacy of DC and chimeric antigen receptor T-cell vaccines will be discussed. Moreover, we will review the influence of IL-10 in the promotion of cancer stemness in concert with the NF-κB signaling pathway with regard to OC progression. Finally, understanding the role of IL-10 and its crosstalk with various cells in the ascitic fluid may contribute to the development of novel immunotherapeutic approaches with the potential to kill drug-resistant OC cells while minimizing toxic side effects.

Tumor-associated macrophages: role in tumorigenesis and immunotherapy implications

Tumor-associated macrophages (TAMs) occupy an important position in the tumor microenvironment (TME), they are a highly plastic heterogeneous population with complex effects on tumorigenesis and development. TAMs secrete a variety of cytokines, chemokines, and proteases, which promote the remodeling of extracellular matrix, tumor cell growth and metastasis, tumor vessel and lymphangiogenesis, and immunosuppression. TAMs with different phenotypes have different effects on tumor proliferation and metastasis. TAMs act a pivotal part in occurrence and development of tumors, and are very attractive target to inhibit tumor growth and metastasis in tumor immunotherapy. This article reviews the interrelationship between TAMs and tumor microenvironment and its related applications in tumor therapy.

Immunohistochemical Analysis of Programmed Death-Ligand 1 Expression in Equine Sarcoids

The aim of the study was to assess the expression of the immune checkpoint inhibitor programmed death-ligand 1 (PD-L1) in equine sarcoids (ES). Programmed death-ligand 1 is expressed by various cancer cells to block T cell-mediated elimination of tumor cells. Antibodies targeting human PD-L1 were tested by immunohistochemistry for their cross-reactivity with equine PD-L1 using formalin-fixed, paraffin-embedded tissues. Our results do not support an important role of PD-L1-mediated immune evasion in ES disease and hence do not offer a rationale for anti-PD-1/PD-L1-based immunotherapy against ES.

Increased Serum Level of Interleukin-10 Predicts Poor Survival and Early Recurrence in Patients With Peripheral T-Cell Lymphomas

Peripheral T cell lymphoma (PTCL) is an alloplasm group of aggressive and lymphoproliferative tumors with heterogeneous morphological changes of mature T cell immunophenotype. It has multiple subtypes and most of them have poor prognosis. Interleukin 10 (IL-10) is one kind of multi-cell-derived and multifunctional cytokine. It regulates the growth and differentiation of cells, participates in inflammation and immune response, plays an important role in tumor and infection, and is closely related to blood system diseases. Therefore, we implemented a retrospective study of 205 patients who were newly diagnosed with PTCL to explore the relationship between IL-10 and prognosis and early recurrence. We found patients with IL-10 ≥3.6 pg/ml achieved a lower CR rate and higher 1-year recurrence rate than patients with IL-10 <3.6 pg/ml (14.4 vs. 51.9%; 17.6 vs. 49.5%). On multivariate analysis, moreover, elevated IL-10 is an extremely important prognostic factor in PTCL, which can lead to worsening of overall survival (OS), low complete response (CR) rate and higher early relapse rate. Therefore, measurement of IL-10 levels in peripheral blood at the initial stage are useful for predicting the prognosis and helping us to make different treatment plans for individual patients. In the near future, IL-10 inhibitors or antagonists may become a new method of immunotargeting therapy for patients with PTCL.

Mechanisms of immune suppression by myeloid-derived suppressor cells: the role of interleukin-10 as a key immunoregulatory cytokine

Chronic immune activation and inflammation are unwanted consequences of many pathological conditions, since they could lead to tissue damage and immune exhaustion, both of which can worsen the pathological condition status. In fact, the immune system is naturally equipped with immunoregulatory cells that can limit immune activation and inflammation. However, chronic activation of downregulatory immune responses is also associated with unwanted consequences that, in turn, could lead to disease progression as seen in the case of cancer and chronic infections. Myeloid-derived suppressor cells (MDSCs) are now considered to play a pivotal role in the pathogenesis of different inflammatory pathological conditions, including different types of cancer and chronic infections. As a potent immunosuppressor cell population, MDSCs can inhibit specific and non-specific immune responses via different mechanisms that, in turn, lead to disease persistence. One such mechanism by which MDSCs can activate their immunosuppressive effects is accomplished by secreting copious amounts of immunosuppressant molecules such as interleukin-10 (IL-10). In this article, we will focus on the pathological role of MDSC expansion in chronic inflammatory conditions including cancer, sepsis/infection, autoimmunity, asthma and ageing, as well as some of the mechanisms by which MDSCs/IL-10 contribute to the disease progression in such conditions.

27-Hydroxycholesterol acts on myeloid immune cells to induce T cell dysfunction, promoting breast cancer progression

Breast cancer remains one of the leading causes of cancer mortality in the US. Elevated cholesterol is a major risk factor for breast cancer onset and recurrence, while cholesterol-lowering drugs, such as statins, are associated with a good prognosis. Previous work in murine models showed that cholesterol increases breast cancer metastasis, and the pro-metastatic effects of cholesterol were due to its primary metabolite, 27-hydroxycholesterol (27HC). In our prior work, myeloid cells were found to be required for the pro-metastatic effects of 27HC, but their precise contribution remains unclear. Here we report that 27HC impairs T cell expansion and cytotoxic function through its actions on myeloid cells, including macrophages, in a Liver X receptor (LXR) dependent manner. Many oxysterols and LXR ligands had similar effects on T cell expansion. Moreover, their ability to induce the LXR target gene ABCA1 was associated with their effectiveness in impairing T cell expansion. Induction of T cell apoptosis was likely one mediator of this impairment. Interestingly, the enzyme responsible for the synthesis of 27HC, CYP27A1, is highly expressed in myeloid cells, suggesting that 27HC may have important autocrine or paracrine functions in these cells, a hypothesis supported by our finding that breast cancer metastasis was reduced in mice with a myeloid specific knockout of CYP27A1. Importantly, pharmacologic inhibition of CYP27A1 reduced metastatic growth and improved the efficacy of checkpoint inhibitor, anti-PD-L1. Taken together, our work suggests that targeting the CYP27A1 axis in myeloid cells may present therapeutic benefits and improve the response rate to immune therapies in breast cancer.

Association study indicates combined effect of interleukin-10 and angiotensin-converting enzyme in basal cell carcinoma development

Cytokines involved in inflammatory and immune response have been associated with risk for development of basal cell carcinoma (BCC). In this study, three functional DNA polymorphisms affecting gene expression were investigated in 54 BCC patients and 111 healthy controls: interleukin-1b (IL-1b) +3953C/T, interleukin-10 (IL-10) - 1082G/A and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms. Significant increase of the variant alleles was observed in IL-10 - 1082G (P = 0.019) and in ACE D (P = 0.003) in BCC patients in comparison to controls. Multivariate logistic regression models evaluated the contribution of homozygous and heterozygous variant polymorphisms to the risk for BCC development. The studied polymorphisms influencing the expression of IL-10 and ACE genes were recognized as potential predictive factors for BCC. These findings suggest a possible molecular mechanism leading to BCC development that is likely to involve the activation of angiotensin receptors in combination with increased plasma levels of IL-10 in patients.

Microenvironment Molecular Profile Combining Glycation Adducts and Cytokines Patterns on Secretome of Short-term Blood-derived Cultures during Tumour Progression

Cancer cells are known to secrete many bioactive factors acting both with paracrine and autocrine mechanisms by which they condition the surrounding microenvironment. At the same time, the intracytoplasmic metabolic activities microenvironment influences the profile of this secretion. It is well known that cancer cells exhibit prevalent glycolytic metabolism and a more oxidative atmosphere compared to their healthy counterparts; this metabolic phenotype promotes glycate adducts formation and secretion. Considering the exacerbation of metabolic changes during the cancer progression, it is suggestive to explore the potential correlation between the increasing rate of glycan adducts and the specific pattern of secreted cytokines in different phases of cancer disease. We analyzed the secretomes of blood-derived cancer cell cultures from cancer patients and healthy subjects. The relative glycate adducts content in cancer secretomes was higher in comparison to that of healthy samples. Moreover, the stratification based on different phases of cancer disease correlated with a specific cytokines panel. The results obtained open a new perspective of observation of the intricate relationship between metabolome and inflammation in cancer. By using the analysis of secretome combined with a standardized protocol of liquid biopsy, it would be possible to identify specific profiles of molecular markers useful to arrange alternative and personalized medicine strategies.

Poor Clinical Outcomes and Immunoevasive Contexture in Intratumoral IL-10-Producing Macrophages Enriched Gastric Cancer Patients

OBJECTIVE

To investigate the clinical significance of IL-10 tumor-associated macrophages (TAMs) in gastric cancer.

BACKGROUND

Due to the plasticity and diversity of TAMs, it is necessary to phenotypically and functionally classify subsets of TAMs to better understand the critical role of TAMs in cancer progression. TAMs expressing interleukin-10 (IL-10) have been found to facilitate immune evasion in many malignancies, but the role of IL-10 TAMs in gastric cancer remains obscure.

METHODS

Four hundred and sixty-eight tumor tissue microarray specimens, 52 fresh tumor tissue samples of gastric cancer patients from Zhongshan Hospital, and data of 298 gastric cancer patients from the Cancer Genome Atlas (TCGA) were analyzed. IL-10 TAM level and immune contexture were examined by CIBERSORT, immunohistochemistry, and flow cytometry. Clinical outcomes were analyzed by Kaplan-Meier curves and Cox model.

RESULTS

Gastric cancer patients with high IL-10 TAM infiltration exhibited poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy. IL-10 TAM infiltration yielded an immunoevasive tumor microenvironment featured by regulatory T cell infiltration and CD8 T cell dysfunction. The combinational analysis of IL-10 TAM and CD8 T cell infiltration stratified patients into distinct risk groups with different clinical outcomes. Moreover, IL-10 TAM infiltration was correlated with tumor-intrinsic characteristics including EBV status, PD-L1 expression, and genome stability in gastric cancer.

CONCLUSIONS

This study revealed that IL-10 TAMs might drive an immunoevasive microenvironment and determine poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy, indicating IL-10 TAMs could be applied as a potential target for immunotherapeutic approach in gastric cancer.

In Vitro Modeling of the Tumor Microenvironment in Tumor Organoids

BACKGROUND

The tumor microenvironment (TME) represents the many components occupying the space within and surrounding a tumor, including cells, signaling factors, extracellular matrix, and vasculature. Each component has the potential to assume many forms and functions which in turn contribute to the overall state of the TME, and further contribute to the progression and disposition of the tumor itself. The sum of these components can drive a tumor towards progression, keep a migratory tumor at bay, or even control chemotherapeutic response. The wide potential for interaction that the TME is an integral part of a tumor's ecosystem, and it is imperative to include it when studying and modeling cancer in vitro. Fortunately, the development of tissue engineering and biofabrication technologies and methodologies have allowed widespread inclusion of TME-based factors into in vitro tissue-equivalent models.

METHODS

In this review, we compiled contemporary literature sources to provide an overview of the field of TME models, ranging from simple to complex.

RESULTS

We have identified important components of the TME, how they can be included in in vitro study, and cover examples across a range of cancer types.

CONCLUSION

Our goal with this text is to provide a foundation for prospective research into the TME.

The effect of interleukin 10 polymorphisms on breast cancer susceptibility in Han women in Shaanxi Province

Background

Previous studies have reported on several genetic variants related to breast cancer, but a substantial proportion of mutation loci have not yet been identified. In the current study, we aimed to evaluate the association between single nucleotide polymorphisms (SNPs) of interleukin-10 (IL-10) and susceptibility to breast cancer in Shaanxi Han women in China.

Methods

Six SNPs were genotyped in 530 breast cancer patients and 628 healthy women from the First Affiliated Hospital of Xi’an Jiaotong University Hospital. Odds ratios and 95% confidence intervals were calculated by unconditional logistic regression analysis to assess the association between breast cancer risk and polymorphisms of six loci.

Results

Two SNPs, rs3024490 and rs1800871, were found to be significantly different between breast cancer patients and healthy women. These SNPs also increased the risk of breast cancer in co-dominant and dominant models. Moreover, another SNP, rs1554286, was significantly associated with an increased risk of breast cancer in the co-dominant model. Functional assessments indicated that these three variants may influence the expression and transcription factor binding of IL-10.

Conclusions

Our findings suggest that variants of IL-10 may be likelihood risk factors for the development and progression of breast cancer. Future studies should replicate this study and evaluate functional assessments in Chinese Han women and women from other regions.

New directions in chimeric antigen receptor T cell [CAR-T] therapy and related flow cytometry

Chimeric antigen receptor (CAR) T cells provide a promising approach to the treatment of hematologic malignancies and solid tumors. Flow cytometry is a powerful analytical modality, which plays an expanding role in all stages of CAR T therapy, from lymphocyte collection, to CAR T cell manufacturing, to in vivo monitoring of the infused cells and evaluation of their function in the tumor environment. Therefore, a thorough understanding of the new directions is important for designing and implementing CAR T-related flow cytometry assays in the clinical and investigational settings. However, the speed of new discoveries and the multitude of clinical and preclinical trials make it challenging to keep up to date in this complex field. In this review, we summarize the current state of CAR T therapy, highlight the areas of emergent research, discuss applications of flow cytometry in modern cell therapy, and touch upon several considerations particular to CAR detection and assessing the effectiveness of CAR T therapy.

Inducers, Attractors and Modulators of CD4+ Treg Cells in Non-Small-Cell Lung Cancer

Lung cancer is the leading cause of cancer-associated deaths worldwide, with non-small cell-lung cancer (NSCLC) accounting for approximately 80% of cases. Immune escape has been demonstrated to play a key role in the initiation and progression of NSCLC, although the underlying mechanisms are diverse and their puzzling nature is far from being understood. As a critical participant in immune escape, the CD4⁺ T cell subset of regulatory T (Treg) cells, with their immunosuppressive functions, has been implicated in the occurrence of many types of cancers. Additionally, therapies based on Treg blockade have benefited a portion of cancer patients, including those with NSCLC. Accumulating literature has noted high Treg infiltration in NSCLC tumor tissues, bone marrow, lymph nodes and/or blood; moreover, the tumor milieu is involved in regulating the proliferation, differentiation, recruitment and suppressive functions of Treg cells. Multifarious mechanisms by which CD4⁺ Treg cells are generated, attracted and modulated in the NSCLC milieu will be discussed in this review.

John MA. The promise of immunotherapy in the treatment of young adults with oral tongue cancer

Historically considered a disease of the older male resulting from cumulative tobacco and alcohol use, more recently we have witnessed a rise in the global incidence of oral tongue squamous cell carcinoma in younger adults, particularly those without any identifiable risk factor exposure. These patients appear to be at higher overall risk for locoregional treatment failure and often experience a more heterogeneous clinical course, with some afflicted with particularly aggressive, rapidly progressive disease. Recent research efforts have supported the idea that although this disease may be genomically similar in these groups, and molecular differences in the tumor immune microenvironment may account for biological differences between young and older patients, as well as patients with and without exposure to alcohol or tobacco. In this review, we seek to summarize current knowledge regarding pathogenesis of oral tongue carcinoma in the young adult patient and examine the potential role of the immune response in disease progression and as a target for novel immunotherapies.

Codelivery of STAT3 siRNA and BV6 by carboxymethyl dextran trimethyl chitosan nanoparticles suppresses cancer cell progression

High expression of inhibitor of apoptosis (IAP) molecules in cancer cells promotes cancer cell chemoresistance. Use of BV6, a well-known IAP inhibitor, along with inhibition of signal transducer and activator of transcription 3 (STAT3), which is an important factor in the survival of tumor cells, and NIK as a mediator of BV6 unpredicted side effects, can induce effective apoptosis in tumor cells. The present study has investigated the combination therapy of cancer cells using Carboxymethyl Dextran-conjugated trimethyl chitosan (TMC-CMD) nanoparticles (NPs) loaded with NIK/STAT3-specific siRNA and BV6 to synergistically induce apoptosis in the breast, colorectal and melanoma cancer cell lines. Our results showed that in addition to enhanced pro-apoptotic effects, this combination therapy reduced proliferation, cell migration, colony formation, and angiogenesis, along with expression of factors including IL-10 and HIF in tumor cells. The results indicate the potential of this combination therapy for further investigation in animal models of cancer.

Tumor-Associated Macrophages: Recent Insights and Therapies

Macrophages, which have functions of engulfing and digesting foreign substances, can clear away harmful matter, including cellular debris and tumor cells. Based on the condition of the internal environment, circulating monocytes give rise to mature macrophages, and when they are recruited into the tumor microenvironment and in suitable conditions, they are converted into tumor-associated macrophages (TAMs). Generally, macrophages grow into two main groups called classically activated macrophages (M1) and alternatively activated macrophages (M2). M2 and a small fraction of M1 cells, also known as TAMs, not only lack the function of phagocytizing tumor cells but also help these tumor cells escape from being killed and help them spread to other tissues and organs. In this review, we introduce several mechanisms by which macrophages play a role in the immune regulation of tumor cells, including both killing factors and promoting effects. Furthermore, the targeted therapy for treating tumors based on macrophages is also referred to in our review. We confirm that further studies of macrophage-focused therapeutic strategies and their use in clinical practice are needed to verify their superior efficacy and potential in cancer treatment.

Combination of Gas Plasma and Radiotherapy Has Immunostimulatory Potential and Additive Toxicity in Murine Melanoma Cells in Vitro

Despite continuous advances in therapy, malignant melanoma is still among the deadliest types of cancer. At the same time, owing to its high plasticity and immunogenicity, melanoma is regarded as a model tumor entity when testing new treatment approaches. Cold physical plasma is a novel anticancer tool that utilizes a plethora of reactive oxygen species (ROS) being deposited on the target cells and tissues. To test whether plasma treatment would enhance the toxicity of an established antitumor therapy, ionizing radiation, we combined both physical treatment modalities targeting B16F10 murine melanoma cell in vitro. Repeated rather than single radiotherapy, in combination with gas plasma-introduced ROS, induced apoptosis and cell cycle arrest in an additive fashion. In tendency, gas plasma treatment sensitized the cells to subsequent radiotherapy rather than the other way around. This was concomitant with increased levels of TNFα, IL6, and GM-CSF in supernatants. Murine JAWS dendritic cells cultured in these supernatants showed an increased expression of cell surface activation markers, such as MHCII and CD83. For PD-L1 and PD-L2, increased expression was observed. Our results are the first to suggest an additive therapeutic effect of gas plasma and radiotherapy, and translational tumor models are needed to develop this concept further.

Genetic Polymorphisms in IL-10 Promoter Are Associated With Smoking and Prostate Cancer Risk in African Americans

BACKGROUND/AIM

Even though prostate cancer (PCa) has good prognosis, there is a discrepancy in the risk among ethnic groups, with high morbidity in African American men. Single nucleotide polymorphisms (SNPs) in interleukin 10 (IL-10) have been associated with inflammation and cancer risk. We investigated the association of five SNPs in the IL-10 promoter with clinical features such as Gleason score and smoking.

MATERIALS AND METHODS

A total of 413 DNA samples were obtained from a nested case-control study of African American males who were genotyped for 5 SNPs utilizing pyrosequencing. Multiple and binary logistic regression models were applied to analyze the clinical and genotypic data.

RESULTS

rs12122923 and rs1800871 were associated with PCa risk. Smoking was also found to increase the risk of PCa by 1.6-fold. rs1800893 was found to be associated with lower grades for prostate cancer.

CONCLUSION

IL-10 promoter polymorphisms might be a risk factor for PCa development in smoking subjects and PCa progression.

Lipophilicity of Bacteriochlorin-Based Photosensitizers as a Determinant for PDT Optimization through the Modulation of the Inflammatory Mediators

: Photodynamic therapy (PDT) augments the host antitumor immune response, but the role of the PDT effect on the tumor microenvironment in dependence on the type of photosensitizer and/or therapeutic protocols has not been clearly elucidated. We employed three bacteriochlorins (F2BOH, F2BMet and Cl2BHep) of different polarity that absorb near-infrared light (NIR) and generated a large amount of reactive oxygen species (ROS) to compare the PDT efficacy after various drug-to-light intervals: 15 min. (V-PDT), 3h (E-PDT) and 72h (C-PDT). We also performed the analysis of the molecular mechanisms of PDT crucial for the generation of the long-lasting antitumor immune response. PDT-induced damage affected the integrity of the host tissue and developed acute (protocol-dependent) local inflammation, which in turn led to the infiltration of neutrophils and macrophages. In order to further confirm this hypothesis, a number of proteins in the plasma of PDT-treated mice were identified. Among a wide range of cytokines (IL-6, IL-10, IL-13, IL-15, TNF-α, GM-CSF), chemokines (KC, MCP-1, MIP1α, MIP1β, MIP2) and growth factors (VEGF) released after PDT, an important role was assigned to IL-6. PDT protocols optimized for studied bacteriochlorins led to a significant increase in the survival rate of BALB/c mice bearing CT26 tumors, but each photosensitizer (PS) was more or less potent, depending on the applied DLI (15 min, 3 h or 72 h). Hydrophilic (F2BOH) and amphiphilic (F2BMet) PSs were equally effective in V-PDT (>80 cure rate). F2BMet was the most efficient in E-PDT (DLI = 3h), leading to a cure of 65 % of the animals. Finally, the most powerful PS in the C-PDT (DLI = 72 h) regimen turned out to be the most hydrophobic compound (Cl2BHep), allowing 100 % of treated animals to be cured at a light dose of only 45 J/cm2.

Therapeutic Monoclonal Antibodies Targeting Immune Checkpoints for the Treatment of Solid Tumors

Recently, modulation of immune checkpoints has risen to prominence as a means to treat a number of solid malignancies, given the durable response seen in many patients and improved side effect profile compared to conventional chemotherapeutic agents. Several classes of immune checkpoint modulators have been developed. Here, we review current monoclonal antibodies directed against immune checkpoints that are employed in practice today. We discuss the history, mechanism, indications, and clinical data for each class of therapies. Furthermore, we review the challenges to durable tumor responses that are seen in some patients and discuss possible interventions to circumvent these barriers.

T Regulatory Cells and Priming the Suppressive Tumor Microenvironment

Treg play a central role in maintenance of self tolerance and homeostasis through suppression of self-reactive T cell populations. In addition to that role, Treg also survey cancers and suppress anti-tumor immune responses. Thus, understanding the unique attributes of Treg-tumor interactions may permit control of this pathologic suppression without interfering with homeostatic self-tolerance. This review will define the unique role of Treg in cancer growth, and the ways by which Treg inhibit a robust anti-tumor immune response. There will be specific focus placed on Treg homing to the tumor microenvironment (TME), TME formation of induced Treg (iTreg), mechanisms of suppression that underpin cancer immune escape, and trophic nonimmunologic effects of Treg on tumor cells.

Activation of dendritic cells by targeted DNA: a potential addition to the armamentarium for anti-cancer immunotherapy

In the past decade, remarkable progress has been made in immunotherapy against cancer. Specifically, the introduction of immune checkpoint inhibitors has revolutionized the field. However, many patients are unable to benefit significantly from this treatment option. One of the major reasons for this is most likely the absence of an adequate tumor-specific T cell response in these patients. A way to circumvent this problem might be to combine immune checkpoint inhibitor treatment with new strategies to activate tumor-specific T cells. One such strategy could be to activate and mature dendritic cells in situ. Dendritic cells carry an array of external and internal pattern recognition receptors that induce cell activation and maturation when interacting with their corresponding damage-associated or pathogen-associated molecular patterns (DAMPs or PAMPs). Targeting such molecular patterns directly to dendritic cells might be a way to evoke stronger immune responses. Here, we review our recent findings using antibody-targeted DNA. We summarize the results from our experiments showing that dendritic cells can be actively targeted in vivo through the α_Xβ₂ integrin subunit CD11c, and that DNA delivered through this receptor in vitro leads to maturation of dendritic cells via the cytosolic cGAS/STING DNA-sensing pathway.

G protein-coupled receptor kinase 2 regulating β2-adrenergic receptor signaling in M2-polarized macrophages contributes to hepatocellular carcinoma progression

Background: β2-adrenoceptors (β2-ARs) are expressed on the surface of immune cells, including tumor-associated macrophages (TAMs). Previous studies have demonstrated that the expression of β2-ARs in hepatocellular carcinoma (HCC) is significantly increased in vitro. However, the role of β2-AR in M2-polarized macrophages remains unclear. G protein-coupled receptor kinase 2 (GRK2) can regulate G protein-coupled receptor (GPCR). Previous studies showed that down-regulation of GRK2 in HCC contributes the HCC progression, but it still remains unclear whether the regulation of β2-AR in M2-polarized macrophages by GRK2 can promote HCC.

Purpose: The present study was designed to investigate the role of activated β2-AR in M2-polarized macrophages in the HCC progression and GRK2 regulatory effect, as well as the underlying mechanisms involved.

Results: The results demonstrated that the M2-polarized macrophages were increased with HCC progression. In vitro, the activation of β2-AR by terbutaline in M2-polarized macrophages elevated the proliferative, migratory and invasive attributes of HCC cells. Furthermore, GRK2 down-regulation in β2-AR activated M2-polarized macrophages activated the downstream cyclic adenosine monophosphate (cAMP)/protein kinase A/cAMP-response element binding protein and cAMP/interleukin-6/signal transducer and the activator of transcription 3 signaling pathways, contributing to the secretion of tumor-associated cytokines, and thus resulting in the promotion of malignant biological behavior in HCC cells.

Conclusion: These findings suggest that the regulation of β2-AR occurs through the silencing of GRK2 in M2-polarized macrophages, which is conducive to HCC development, through its engagement in the activation of downstream signaling.

IL-10/STAT3/SOCS3 Axis Is Involved in the Anti-inflammatory Effect of Benznidazole

Anti-parasitic treatment for Chagas disease mainly relies on benznidazole, which is virtually the only drug available in the market. Besides its anti-parasitic effects, benznidazole has anti-inflammatory properties. In this work we studied the mechanisms involved in the latter, demonstrating the participation of the IL-10/STAT3/SOCS3 pathway. To achieve this goal, the anti-inflammatory properties of benznidazole were studied using an in vitro model of cardiomyocyte primary culture stimulated with LPS. LPS increased both SOCS3 expression and STAT3 phosphorylation. The addition of benznidazole increased their expression even further. Specific inhibition of STAT3 precluded this effect, suggesting a role for STAT3 in the increase of SOCS3 expression induced by benznidazole. To assess the participation of SOCS3 in the anti-inflammatory effect of benznidazole, we accomplished specific knockdown of SOCS3 with siRNA. Silencing of SOCS3 in cardiomyocytes precluded the inhibitory effects of benznidazole on TNF-α, IL-6, iNOS expression and NO release. Moreover, in the absence of SOCS3, benznidazole could neither prevent IKK phosphorylation nor IκBα degradation, supporting the notion that SOCS3 is required for the benznidazole-mediated inhibition of the NF-κB pathway. Previously, we demonstrated that IL-10 increases the expression of SOCS3 in cultured cardiomyocytes. Here, we found that benznidazole shows a trend to increased IL-10 expression. To evaluate whether benznidazole increased SOCS3 in an IL-10-dependent manner, cardiomyocytes from IL-10 knockout mice were pre-treated with benznidazole and stimulated with LPS. Benznidazole neither inhibited NO release nor avoid IKK phosphorylation or IκBα degradation, showing that IL-10 is required for benznidazole-mediated inhibition of NF-κB. Moreover, exogenous addition of IL-10 to IL-10 knockout cardiomyocytes restored the inhibitory effect of benznidazole on NO release. The results reported herein show, for the first time, that the IL-10/STAT3/SOCS3 axis is involved in the anti-inflammatory effects of benznidazole. These findings may add up to new therapeutic strategies for chronic Chagas disease given its inflammatory nature.

Nano-Strategies to Target Breast Cancer-Associated Fibroblasts: Rearranging the Tumor Microenvironment to Achieve Antitumor Efficacy

Cancer-associated fibroblasts (CAF) are the most abundant cells of the tumor stroma and they critically influence cancer growth through control of the surrounding tumor microenvironment (TME). CAF-orchestrated reactive stroma, composed of pro-tumorigenic cytokines and growth factors, matrix components, neovessels, and deregulated immune cells, is associated with poor prognosis in multiple carcinomas, including breast cancer. Therefore, beyond cancer cells killing, researchers are currently focusing on TME as strategy to fight breast cancer. In recent years, nanomedicine has provided a number of smart delivery systems based on active targeting of breast CAF and immune-mediated overcome of chemoresistance. Many efforts have been made both to eradicate breast CAF and to reshape their identity and function. Nano-strategies for CAF targeting profoundly contribute to enhance chemosensitivity of breast tumors, enabling access of cytotoxic T-cells and reducing immunosuppressive signals. TME rearrangement also includes reorganization of the extracellular matrix to enhance permeability to chemotherapeutics, and nano-systems for smart coupling of chemo- and immune-therapy, by increasing immunogenicity and stimulating antitumor immunity. The present paper reviews the current state-of-the-art on nano-strategies to target breast CAF and TME. Finally, we consider and discuss future translational perspectives of proposed nano-strategies for clinical application in breast cancer.

Decidua Basalis Mesenchymal Stem Cells Favor Inflammatory M1 Macrophage Differentiation In Vitro

Placental mesenchymal stem cells from maternal decidua basalis tissue (DBMSCs) are promising cells for tissue repair because of their multilineage differentiation and ability to protect endothelial cells from injury. Here, we examined DBMSC interaction with macrophages and whether this interaction could modulate the characteristics and functions of these macrophages. We induced monocytes to differentiate into M1-like macrophages in the presence of DBMSCs. DBMSC effects on differentiation were evaluated using microscopy, flow cytometry, and ELISA. DBMSC effects on M1-like macrophage induction of T cell function were also examined. The culture of DBMSCs with monocytes did not inhibit monocyte differentiation into M1-like inflammatory macrophages. This was confirmed by the morphological appearance of M1-like macrophages, increased expression of inflammatory molecules, and reduced expression of anti-inflammatory molecules. In addition, DBMSCs did not interfere with M1-like macrophage phagocytic activity; rather, they induced stimulatory effects of M1-like macrophages on CD4⁺ T cell proliferation and subsequent secretion of inflammatory molecules by T cells. We showed that DBMSCs enhanced the differentiation of M1-like inflammatory macrophages, which function as antitumor cells. Therefore, our findings suggest that DBMSCs are inflammatory cells that could be useful in cancer treatment via the enhancement of M1- like macrophages.

Addressing barriers to effective cancer immunotherapy with nanotechnology: achievements, challenges, and roadmap to the next generation of nanoimmunotherapeutics

Cancer is a complex systemic disorder that affects many organs and tissues and arises from the altered function of multiple cellular and molecular mechanisms. One of the systems malfunctioning in cancer is the immune system. Restoring and improving the ability of the immune system to effectively recognize and eradicate cancer is the main focus of immunotherapy, a topic which has garnered recent and significant interest. The initial excitement about immunotherapy, however, has been challenged by its limited efficacy in certain patient populations and the development of adverse effects such as therapeutic resistance and autoimmunity. At the same time, a number of advances in the field of nanotechnology have sought to address the challenges faced by modern immunotherapeutics and allow these therapeutic strategies to realize their full potential. This endeavour requires an understanding of not only the immunological barriers in cancer but also the mechanisms by which modern technologies and immunotherapeutics modulate the function of the immune system. Herein, we summarize the major barriers relevant to cancer immunotherapy and review current progress in addressing these obstacles using various approaches and clinically approved therapies. We then discuss the remaining challenges and how they can be addressed by nanotechnology. We lay out translational considerations relevant to the therapies described and propose a framework for the development of next-generation nanotechnology-enabled immunotherapies.

Mechanisms of Primary and Secondary Resistance to Immune Checkpoint Inhibitors in Cancer

Immune checkpoint inhibitors (ICPis) have revolutionized cancer therapy with broad activities against a wide range of malignancies. However, in many malignancies their efficacy remains limited due to the primary resistance. Furthermore, a high percentage of patients develop progression due to the secondary resistance even after obtaining a response or achieving a stable disease. In this review, we will discuss the mechanisms that underlie the primary and secondary resistance to ICPis in cancer immunotherapy and provide an overview to impart a broad understanding of the critical issues that are encountered in clinical oncology practice.

Type 2 Innate Lymphoid Cells Impede IL-33-Mediated Tumor Suppression

Although a number of studies have recently explored the contribution of the adaptive immunity in IL-33-mediated antitumor effects, innate immune involvement has been poorly characterized. Utilizing Rag1^-/- mice (lacking T and B lymphocytes), we show in this study that either systemic administration of recombinant IL-33 or ectopic expression of IL-33 in melanoma cells is sufficient to inhibit tumor growth independent of adaptive antitumor immunity. We have demonstrated that IL-33-mediated antitumor effects depend on expansion and activation of NK cells. Interestingly, IL-33 also promoted the expansion of active type 2 innate lymphoid cells (ILC2s) via its receptor, ST2, which in turn inhibited NK activation and cytotoxicity. This IL-33-induced ILC2 activity coincided with greater expression of the immunosuppressive ectoenzyme CD73. Removal of CD73 from ILC2s in culture with NK cells resulted in markedly increased activation levels in NK cells, offering a potential mechanism by which ILC2s might suppress NK cell-mediated tumor killing. Thus, our data reveal an important contribution of IL-33-induced ILC2 to tumor growth by weakening NK cell activation and tumor killing, regardless of adaptive immunity.

Local Blockade of Interleukin 10 and C-X-C Motif Chemokine Ligand 12 with Nano-Delivery Promotes Antitumor Response in Murine Cancers

In many cancers, the tumor microenvironment (TME) is largely immune suppressive, blocking the antitumor immunity and resulting in immunotherapy resistance. Interleukin 10 (IL-10) is a major player controlling the immunosuppressive TME in different murine tumor models. Increased IL-10 production suppresses intratumoral dendritic cell production of interleukin 12, thereby limiting antitumor cytotoxic T-cell responses and activation of NK cells during therapy. We engineered, formulated, and delivered genes encoding an IL-10 protein trap to change immunosuppressive TME, which could enhance antitumor immunity. Additionally, to achieve stronger and long-term therapeutic efficacy in a pancreatic cancer model, we targeted C-X-C motif chemokine ligand 12 (CXCL12), a key factor for inhibiting T-cell tumor infiltration, and simultaneously delivered an IL-10 trap. Following three injections of the lipid-protamine-DNA (LPD) nanoparticles loaded with trap genes (IL-10 trap and CXCL12 trap), we found tumor growth reduction and significantly prolonged survival of the host compared to control groups. Furthermore, the combination trap gene treatment significantly reduced immunosuppressive cells, such as M2 macrophages, MDSCs, and PD-L1⁺ cells, and activated immunosuppressive tolerogenic dendritic cells, NK cells, and macrophages intratumorally. We have also shown that, when effectively delivered to the tumor, the IL-10 trap gene alone can inhibit triple-negative breast cancer growth. This strategy may allow clinicians and researchers to change the immunosuppressive microenvironment in the tumor with either a single therapeutic agent or in combination with other immunotherapies to prime the immune system, preventing cancer invasion and prolonging patient survival.

Serum levels of IL-6, IL-8, and IL-10 are indicators of prognosis in pancreatic cancer

OBJECTIVE

Early detection and prognosis prediction are critical to improve patient survival in pancreatic cancer. This study aimed to investigate whether interleukins could serve as indicators of prognosis in pancreatic cancer.

METHODS

Sixty-eight patients with pancreatic cancer were enrolled in the study during the period between 2012 and 2014. The serum levels of a broad spectrum of interleukins in these patients were determined, including IL-1β, IL-2, IL-6, IL-8, IL-10, IL-13, IL-15, and IL-23.

RESULTS

IL-6, IL-8, and IL-10 showed significant positive correlations with each other. Moreover, high levels of serum IL-6, IL-8, and IL-10 were independently strongly associated with poor survival of patients with pancreatic cancer.

CONCLUSIONS

Our results suggest that serum levels of IL-6, IL-8, and IL-10 could be useful markers for prediction of prognosis in patients with pancreatic cancer.

IL-10 is overexpressed in human cutaneous T-cell lymphoma and is required for maximal tumor growth in a mouse model

A crucial question pertains to a role of IL-10 as a tumorigenic factor, or just a marker of advanced disease in cutaneous T-cell lymphoma (CTCL). Herein, we measured significantly elevated IL-10 mRNA in a cohort of skin samples of patients with CTCL. Increased IL-10 was also detected in the tumor microenvironment of an established inflammation-dependent murine model of using MBL2 T lymphoma cells. Conditioned media from MBL2 cells was able to stimulate IL-10 production in bone marrow-derived macrophages in an IL-4-dependent manner. Implanted MBL2 T-cell lymphomas in IL-10KO mice were 50% smaller, accompanied by decreased numbers of infiltrating macrophages and reduced efficiency of M2-polarization compared with wild-type mice. With anti-IL-10R mAb treatment, both wild-type tumor-bearing mice and IL-10KO mice exhibited a further growth inhibition. Our data indicate that targeting IL-10 signaling with neutralizing antibodies to IL-10 or its receptor may have a great potential for advanced CTCL therapy.

Th1-Biased Immunomodulation and In Vivo Antitumor Effect of a Novel Piperine Analogue

Natural products have an important role as prototypes in the synthesis of new anticancer drugs. Piperine is an alkaloid amide with antitumor activity and significant toxicity. Then, the N-(p-nitrophenyl)acetamide piperinoate (HE-02) was synthesized, and tested for toxicological and antitumor effects. The toxicity was evaluated in vitro (on RAW 264.7 cells and mice erythrocytes) and in vivo (acute toxicity in mice). The Ehrlich ascites carcinoma model was used to evaluate the antitumor activity of HE-02 (6.25, 12.5 or 25 mg/kg, intraperitoneally, i.p.), as well as toxicity. HE-02 induced only 5.01% of hemolysis, and reduced the viability of RAW 264.7 cells by 49.75% at 1000 µg/mL. LD50 (lethal dose 50%) was estimated at around 2000 mg/kg (i.p.). HE-02 reduced Ehrlich tumor cell viability and peritumoral microvessels density. There was an increase of Th1 helper T lymphocytes cytokine profile levels (IL-1β, TNF-α, IL-12) and a decrease of Th2 cytokine profile (IL-4, IL-10). Moreover, an increase was observed on reactive oxygen species and nitric oxide production. Weak in vivo toxicological effects were recorded. Our data provide evidence that the piperine analogue HE-02 present low toxicity, and its antitumor effect involves modulation of immune system to a cytotoxic Th1 profile.

Reprogramming the murine colon cancer microenvironment using lentivectors encoding shRNA against IL-10 as a component of a potent DC-based chemoimmunotherapy

Background

The excessive amounts of immunosuppressive factors present in a tumor microenvironment (TME) reduce the effectiveness of cancer vaccines. The main objective of our research was to improve the effectiveness of dendritic cell (DC)-based immunotherapy or chemoimmunotherapy composed of cyclophosphamide (CY) and DCs by application of lentivectors encoding shRNA specific to IL-10 (shIL10 LVs) in murine colon carcinoma MC38 model.

Methods

The efficacy of shIL10 LVs in silencing of IL-10 expression was measured both in vitro and in vivo using Real-Time PCR and ELISA assays. In addition, the influence of intratumorally inoculated lentivectors on MC38 tumor microenvironment was examined using flow cytometry method. The effect of applied therapeutic schemes was determined by measurement of tumor growth inhibition and activation state of local and systemic immune response.

Results

We observed that intratumorally inoculated shIL10 LVs transduced tumor and TME-infiltrating cells and reduced the secretion of IL-10. Application of shIL10 LVs for three consecutive weeks initiated tumor growth inhibition, whereas treatment with shIL10 LVs and BMDC/TAg did not enhance the antitumor effect. However, when pretreatment with CY was introduced to the proposed scheme, we noticed high MC38 tumor growth inhibition accompanied by reduction of MDSCs and Tregs in TME, as well as activation of potent local and systemic Th1-type antitumor response.

Conclusions

The obtained data shows that remodeling of TME by shIL10 LVs and CY enhances DC activity and supports them during regeneration and actuation of a potent antitumor response. Therefore, therapeutic strategies aimed at local IL-10 elimination using lentiviral vectors should be further investigated in context of combined chemoimmunotherapies.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0799-y) contains supplementary material, which is available to authorized users.

Tumor Necrosis Factor α and Regulatory T Cells in Oncoimmunology

Tumor necrosis factor α (TNF) is a potent pro-inflammatory cytokine that has deleterious effect in some autoimmune diseases, which led to the use of anti-TNF drugs in some of these diseases. However, some rare patients treated with these drugs paradoxically develop an aggravation of their disease or new onset autoimmunity, revealing an immunosuppressive facet of TNF. A possible mechanism of this observation is the direct and positive effect of TNF on regulatory T cells (Tregs) through its binding to the TNF receptor type 2 (TNFR2). Indeed, TNF is able to increase expansion, stability, and possibly function of Tregs via TNFR2. In this review, we discuss the role of TNF in graft-versus-host disease as an example of the ambivalence of this cytokine in the pathophysiology of an immunopathology, highlighting the therapeutic potential of triggering TNFR2 to boost Treg expansion. We also describe new targets in immunotherapy of cancer, emphasizing on the putative suppressive effect of TNF in antitumor immunity and of the interest of blocking TNFR2 to regulate the Treg compartment.

The role of trophoblastic epigenetic reprogrammation in benign tumor cells on malignant progression: A molecular hypothesis

Cancer tissues and placental ones share many properties such as invasiveness, metastasis and local immunosuppressive effects. The goal of the present article is to hypothesize a theory about cancer origin that links placental and cancerous tissues at molecular level. This hypothesis explain that cancer origin could be due to low hypoxic conditions in the peripheral zones of benign tumors which might up-regulate the expression of IGF2, and, consequently, trophoblastic genes. In fact, many phenotypic characteristics and molecular markers are shared between these two cell types (cancerous and trophoblastics ones), providing evidences to support this hypothesis. As a consequence, it could be interesting to demonstrate whether cancer start with a cellular reprogrammation towards a trophoblastic fate in order to design new antitumoral strategies focused on this fact.

Structural characterization of a polysaccharide from Sargassum henslowianum, and its immunomodulatory effect on gastric cancer rat

A complicated sulfated fucoidan, SHPPB2, was purified from Sargassum henslowianum by DEAE-cellulose 52 and Sephacryl S-300 column chromatography. Via chemical and spectral method, SHPPB2 was found to contain mannose, glucuronic acid, galactose, xylose, and fucose, in a ratio of 17.4: 13.5: 10.5: 16.8: 41.8, as well as 21.4% of sulfate. The methylation analysis demonstrated terminal, 3-, 4-, 2, 3-, and 3, 4- linked fucose, 2-, 2, 3-, 2, 4-, and 2, 4, 6- linked mannose, terminal, 4-, 6-, 2, 4-, 3, 4-, and 3, 6- linked galactose, terminal and 4- linked xylose, and 4- linked glucuronic acid. In addition, the sulfate groups were substituted on the C-2, C-3 or C-4 of 3- and 4- linked fucose, on the C-4 or C-6 of 2- linked mannose, and on C-2 or C-3 of 4- and 6- linked galactose. With the treatment of SHPPB2 in the N-methyl-N'-nitro-nitrosoguanidine (MNNG) induced gastric cancer rats, it was observed with an increased body weight, and improved immune organ indices. Furthermore, SHPPB2 could significantly promote splenocyte proliferation induced by ConA or LPS in gastric cancer rats, and improve anti-inflammatory cytokines (IL-2, IL-4, and IL-10) secretion, but reduce pro-inflammatory cytokines (IL-6 and TNF-α). Taken together, it suggested that SHPPB2 could improve immune function in gastric cancer rats. Thus, it could be explored as a potential immuno-therapy for gastric cancer treatment.

Treg and NK cells related cytokines are associated with deep rectosigmoid endometriosis and clinical symptoms related to the disease

The aim of this study was to evaluate Treg and NK cells related cytokines in deep infiltrating endometriosis lesions and its relationship with clinical symptoms of the disease. mRNA expression of Transforming Growth Factor Beta (TGFB), Interleukin (IL)10, Interferon Gamma (IFNG), IL7, and IL15 was analyzed by Real-Time PCR in eutopic endometrium and rectosigmoid lesions from 11 women with deep infiltrating endometriosis and in eutopic endometrium from 11 healthy women. IL10, IFNG, and IL7 expression was significantly higher in endometriotic bowel lesions than in eutopic endometrium from women with endometriosis. IL10 and TGFB expression was significantly higher in endometriotic bowel lesions than in eutopic endometrium from healthy women. In addition, TGFB and IL15 levels correlated positively with deep dyspareunia and cyclic dyschezia, respectively, while IL7 levels correlated negatively with dysmenorrhea. Deep infiltrating rectosigmoid endometriosis displays alterations in Treg and NK cells related cytokine, and TGFB, IL7 and IL15 expression is related with dyspareunia, dysmenorrhea and cyclic dyschezia, respectively, in patients with the disease.

When Immune Cells Turn Bad-Tumor-Associated Microglia/Macrophages in Glioma

As a substantial part of the brain tumor microenvironment (TME), glioma-associated microglia/macrophages (GAMs) have an emerging role in tumor progression and in controlling anti-tumor immune responses. We review challenges and improvements of cell models and highlight the contribution of this highly plastic cell population to an immunosuppressive TME, besides their well-known functional role regarding glioma cell invasion and angiogenesis. Finally, we summarize first therapeutic interventions to target GAMs and their effect on the immunobiology of gliomas, focusing on their interaction with T cells.

High macrophage PD-L1 expression not responsible for T cell suppression

Tumors are often comprised of microenvironments (TMEs) with a high proportion of cells and molecules that regulate immunity. Peritoneal cavity (PerC) cell culture reproduces key features of TMEs as lymphocyte proliferation is suppressed by PerC macrophages (Mϕs). We monitored the expression of T cell stimulatory (Class II MHC, B7) and inhibitory (PD-L1) molecules by PerC APCs before and after culture and report here that IFNγ-driven PD-L1 expression increased markedly on PerC Mϕs after TCR ligation, even more so than seen with direct APC activation by LPS. Considering the high APC composition of and pronounced PD-L1 expression by PerC cells, it was surprising that blocking PD-1/PD-L1 interaction by mAb neutralization or genetic ablation did not relieve suppression. This result parallels TME challenges observed in the clinic and validates the need for further study of this culture model to inform strategies to promote anti-tumor immunity.

Antitumor Activity of the Chinese Medicine JC-001 Is Mediated by Immunomodulation in a Murine Model of Hepatocellular Carcinoma

JC-001 is a Chinese medicine that has been used to treat liver disease; however, its significance in cancer treatment has not been characterized. In this study, we used an immunocompetent tumor model to characterize the antitumor activity of JC-001. A total of 48 Hepa 1-6 tumor-bearing C57BL/6 mice were randomly grouped into 4 groups and treated with H2O or JC-001 via oral administration. After hepatoma cell lines, including HepG2, Hep3B, SK-Hep-1, and Hepa 1-6, underwent 96 hours of JC-001 treatment, a low cytotoxic effect was observed. In contrast, no direct cytotoxic effect of JC-001 on a normal human liver cell line, THLE-3, was observed under the same incubation conditions. Using a murine tumor model, we found that tumor growth could be inhibited by JC-001 in C57BL/6 mice but not in immunodeficient mice. Histopathological analysis of tumors from C57BL/6 mice revealed immune cell infiltration in tumors from the JC-001-treated group, as observed by hematoxylin and eosin staining; in addition, Ki67, hypoxia-inducible factor-1-α, and high mobility group box 1 expression levels were suppressed in the tumors. Both the coculture assay and murine spleen mRNA quantitative PCR analyses demonstrated that JC-001 could suppress Th17 immunity. Our data suggest that JC-001 is a Chinese medicine with low cytotoxicity that can significantly suppress tumor growth by immune regulation. This herbal remedy has great potential for future clinical application in hepatoma therapy.

Combination of CD40 Agonism and CSF-1R Blockade Reconditions Tumor-Associated Macrophages and Drives Potent Antitumor Immunity

Efficacious antitumor immune responses must overcome multiple suppressive mechanisms in the tumor microenvironment to control cancer progression. In this study, we demonstrate that dual targeting of suppressive myeloid populations by inhibiting CSF-1/CSF-1R signaling and activation of antigen-presenting cells with agonist anti-CD40 treatment confers superior antitumor efficacy and increased survival compared with monotherapy treatment in preclinical tumor models. Concurrent CSF-1R blockade and CD40 agonism lead to profound changes in the composition of immune infiltrates, causing an overall decrease in immunosuppressive cells and a shift toward a more inflammatory milieu. Anti-CD40/anti-CSF-1R-treated tumors contain decreased tumor-associated macrophages and Foxp3⁺ regulatory T cells. This combination approach increases maturation and differentiation of proinflammatory macrophages and dendritic cells and also drives potent priming of effector T cells in draining lymph nodes. As a result, tumor-infiltrating effector T cells exhibit improved responses to tumor antigen rechallenge. These studies show that combining therapeutic approaches may simultaneously remove inhibitory immune populations and sustain endogenous antitumor immune responses to successfully impair cancer progression. Cancer Immunol Res; 5(12); 1109-21. ©2017 AACR.