Increased Levels of Interleukin-10 in Serum from Patients with Hepatocellular Carcinoma Correlate with Profound Numerical Deficiencies and Immature Phenotype of Circulating Dendritic Cell Subsets

Plasmacytoid dendritic cells at the forefront of anti-cancer immunity: rewiring strategies for tumor microenvironment remodeling

Plasmacytoid dendritic cells (pDCs) are multifaceted immune cells executing various innate immunological functions. Their first line of defence consists in type I interferons (I-IFN) production upon nucleic acids sensing through endosomal Toll-like receptor (TLR) 7- and 9-dependent signalling pathways. Type I IFNs are a class of proinflammatory cytokines that have context-dependent functions on cancer immunosurveillance and immunoediting. In the last few years, different studies have reported that pDCs are also able to sense cytosolic DNA through cGAS-STING (stimulator of interferon genes) pathway eliciting a potent I-IFN production independently of TLR7/9. Human pDCs are also endowed with direct effector functions via the upregulation of TRAIL and production of granzyme B, the latter modulated by cytokines abundant in cancer tissues. pDCs have been detected in a wide variety of human malignant neoplasms, including virus-associated cancers, recruited by chemotactic stimuli. Although the role of pDCs in cancer immune surveillance is still uncompletely understood, their spontaneous activation has been rarely documented; moreover, their presence in the tumor microenvironment (TME) has been associated with a tolerogenic phenotype induced by immunosuppressive cytokines or oncometabolites. Currently tested treatment options can lead to pDCs activation and disruption of the immunosuppressive TME, providing a relevant clinical benefit. On the contrary, the antibody-drug conjugates targeting BDCA-2 on immunosuppressive tumor-associated pDCs (TA-pDCs) could be proposed as novel immunomodulatory therapies to achieve disease control in patients with advance stage hematologic malignancies or solid tumors. This Review integrate recent evidence on the biology of pDCs and their pharmacological modulation, suggesting their relevant role at the forefront of cancer immunity.

The Multifaceted Functionality of Plasmacytoid Dendritic Cells in Gastrointestinal Cancers: A Potential Therapeutic Target?

Gastrointestinal (GI) tumors pose a significant global health burden, necessitating the exploration of novel therapeutic approaches. Plasmacytoid dendritic cells (pDCs) play a crucial role in tumor immunity, exhibiting both anti-tumor and pro-tumor effects. This review aims to summarize the role of pDCs in different types of GI tumors and assess their potential as therapeutic targets. In gastric cancer, hepatocellular carcinoma, and intrahepatic cholangiocarcinoma, increased infiltration of pDCs was associated with a worse outcome, whereas in esophageal cancer, pancreatic cancer, and colorectal cancer, pDC infiltration improved the outcome. Initial animal studies of gastric cancer and hepatocellular carcinoma showed that pDCs could be a successful therapeutic target. In conclusion, pDCs play a multifaceted role in GI tumors, influencing both anti-tumor immunity and tumor progression. Further research is needed to optimize their clinical application and explore combinatorial approaches.

Siglec-H-/- Plasmacytoid Dendritic Cells Protect Against Acute Liver Injury by Suppressing IFN-γ/Th1 Response and Promoting IL-21+ CD4 T Cells

BACKGROUND & AIMS

Siglec-H is a receptor specifically expressed in mouse plasmacytoid dendritic cells (pDCs), which functions as a negative regulator of interferon-α production and plays a critical role in pDC maturation to become antigen-presenting cells. The function of pDCs in autoimmune and inflammatory diseases has been reported. However, the effect of Siglec-H expression in pDCs in liver inflammation and diseases remains unclear.

METHODS

Using the model of concanavalin A-induced acute liver injury (ALI), we investigated the Siglec-H/pDCs axis during ALI in BDCA2 transgenic mice and Siglec-H-/- mice. Anti-BDCA2 antibody, anti-interleukin (IL)-21R antibody, and Stat3 inhibitor were used to specifically deplete pDCs, block IL21 receptor, and inhibit Stat3 signaling, respectively. Splenocytes and purified naive CD4 T cells and bone marrow FLT3L-derived pDCs were cocultured and stimulated with phorbol myristate acetate/ionomycin and CD3/CD28 beads, respectively.

RESULTS

Data showed that specific depletion of pDCs aggravated concanavalin A-induced ALI. Remarkably, alanine aminotransferase, hyaluronic acid, and proinflammatory cytokines IL6 and tumor necrosis factor-α levels were lower in the blood and liver of Siglec-H knockout mice. This was associated with attenuation of both interferon-γ/Th1 response and Stat1 signaling in the liver of Siglec-H knockout mice while intrahepatic IL21 and Stat3 signaling pathways were upregulated. Blocking IL21R or Stat3 signaling in Siglec-H knockout mice restored concanavalin A-induced ALI. Finally, we observed that the Siglec-H-null pDCs exhibited immature and immunosuppressive phenotypes (CCR9LowCD40Low), resulting in reduction of CD4 T-cell activation and promotion of IL21+CD4 T cells in the liver.

CONCLUSIONS

During T-cell-mediated ALI, Siglec-H-null pDCs enhance immune tolerance and promote IL21+CD4 T cells in the liver. Targeting Siglec-H/pDC axis may provide a novel approach to modulate liver inflammation and disease.

Inhibitory receptors of plasmacytoid dendritic cells as possible targets for checkpoint blockade in cancer

Plasmacytoid dendritic cells (pDCs) are the major producers of type I interferons (IFNs), which are essential to mount antiviral and antitumoral immune responses. To avoid exaggerated levels of type I IFNs, which pave the way to immune dysregulation and autoimmunity, pDC activation is strictly regulated by a variety of inhibitory receptors (IRs). In tumors, pDCs display an exhausted phenotype and correlate with an unfavorable prognosis, which largely depends on the accumulation of immunosuppressive cytokines and oncometabolites. This review explores the hypothesis that tumor microenvironment may reduce the release of type I IFNs also by a more pDC-specific mechanism, namely the engagement of IRs. Literature shows that many cancer types express de novo, or overexpress, IR ligands (such as BST2, PCNA, CAECAM-1 and modified surface carbohydrates) which often represent a strong predictor of poor outcome and metastasis. In line with this, tumor cells expressing ligands engaging IRs such as BDCA-2, ILT7, TIM3 and CD44 block pDC activation, while this blocking is prevented when IR engagement or signaling is inhibited. Based on this evidence, we propose that the regulation of IFN secretion by IRs may be regarded as an "innate checkpoint", reminiscent of the function of "classical" adaptive immune checkpoints, like PD1 expressed in CD8+ T cells, which restrain autoimmunity and immunopathology but favor chronic infections and tumors. However, we also point out that further work is needed to fully unravel the biology of tumor-associated pDCs, the neat contribution of pDC exhaustion in tumor growth following the engagement of IRs, especially those expressed also by other leukocytes, and their therapeutic potential as targets of combined immune checkpoint blockade in cancer immunotherapy.

Correlation analysis between peripheral blood dendritic cell subsets and PD-1 in patients with peritoneal adenocarcinoma

The aim of this study was to explore the association between differential percentages of dendritic cell (DC) subsets in peripheral blood and malignancy (grade and lymph node metastasis) of peritoneal adenocarcinoma patients and the frequencies of dendritic cell subsets in the normal controls. The peripheral blood of 30 patients with peritoneal adenocarcinoma and 12 healthy controls were collected for multicolor flow cytometry analysis. Peritoneal adenocarcinoma patients were grouped according to the malignant degree (grade and lymph node metastasis). Percentages of myeloid DCs (mDCs) and its subsets MDC1 and MDC2 in DCs were lower in peripheral blood of patients with peritoneal adenocarcinoma than in normal controls. The percentages of plasmacytoid dendritic cells (pDCs) and CD16+mDCs in DCs were higher than in normal controls. Compared with poor differentiation grade, patients with well/moderate differentiation grade had an increased percentage of CD16+mDCs. Contrary to CD16+mDCs, the percentage of MDC1 was lower in the well/moderate differentiation grade group. In patients with no lymph node metastasis, pDCs and CD16+mDCs levels were higher compared with patients with lymph node metastasis. mDCs and MDC1 levels had opposite results. pDCs were positively correlated with CD16+mDCs in peripheral blood of peritoneal patients, as was mDCs and MDC1. CD16+mDCs were negatively correlated with MDC1. The percentages of pDCs and CD16+mDCs in DCs were positively correlated with CD3+CD8+T cells, and pDCs also positively correlated with CD8+PD-1+T cells. Our results revealed that DCs subsets correlated with peritoneal adenocarcinoma malignancy. Dendritic cells play an independent role in the immune function of peritoneal adenocarcinoma.

Chemoradiotherapy and Lymph Node Metastasis Affect Dendritic Cell Infiltration and Maturation in Regional Lymph Nodes of Laryngeal Cancer

Dendritic cells (DCs) are the most specialized antigen-presenting cells, and lymph nodes (LNs) play an important role in the DC-mediated T-cell response. We evaluated the infiltration of CD1a-positive DCs (CD1a-DCs), i.e., immature DCs, and S100-positive dendritic cells (S100-DCs), a mixture of immature and mature DCs, in 73 cases of laryngeal cancer and its regional LNs. Among them, 31 patients underwent radiotherapy (RT) or chemoradiotherapy (CRT) prior to surgery. No significant difference was found for CD1a-DC infiltration in the primary tumors, metastatic LNs and non-metastatic LNs, while S100-DCs were significantly fewer in number in the primary tumors and metastatic LNs compared to non-metastatic LNs. The cases which showed a high infiltration of S100-DCs in the metastatic LNs appeared to show a favorable prognosis, although statistical significance was not reached. In the RT/CRT group, the infiltration of the CD1a-DCs and S100-DCs was less in the primary tumors and metastatic LNs compared to the treatment-naive group. Conversely, the RT/CRT group showed higher CD1a-DC and S100-DC numbers in the non-metastatic LNs compared to the treatment-naïve group. Thus, DC maturation in metastatic LNs plays an important role in tumor immunity in laryngeal cancer, and the infiltration of DCs into the primary tumor and metastatic LNs is impaired by RT/CRT.

Current insights into the hepatic microenvironment and advances in immunotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and shows high global incidence and mortality rates. The liver is an immune-tolerated organ with a specific immune microenvironment that causes traditional therapeutic approaches to HCC, such as chemotherapy, radiotherapy, and molecular targeted therapy, to have limited efficacy. The dramatic advances in immuno-oncology in the past few decades have modified the paradigm of cancer therapy, ushering in the era of immunotherapy. Currently, despite the rapid integration of cancer immunotherapy into clinical practice, some patients still show no response to treatment. Therefore, a rational approach is to target the tumor microenvironment when developing the next generation of immunotherapy. This review aims to provide insights into the hepatic immune microenvironment in HCC and summarize the mechanisms of action and clinical usage of immunotherapeutic options for HCC, including immune checkpoint blockade, adoptive therapy, cytokine therapy, vaccine therapy, and oncolytic virus-based therapy.

The liver cancer immune microenvironment: Therapeutic implications for hepatocellular carcinoma

The liver is the sixth most common site of primary cancer in humans and the fourth leading cause of cancer-related death in the world. Hepatocellular carcinoma (HCC) accounts for 90% of liver cancers. HCC is a prevalent disease with a progression that is modulated by the immune system. Half of the patients with HCC receive systemic therapies, traditionally sorafenib or lenvatinib, as a first-line therapy. In the last few years, immune-checkpoint inhibitors (ICIs) have revolutionized cancer therapy and have gained an increased interest in the treatment of HCC. In 2020, the combination of atezolizumab (anti-programmed death-ligand 1) and bevacizumab (anti-vascular endothelial growth factor) improved overall survival over sorafenib, resulting in Food and Drug Administration (FDA) approval as a first-line treatment for patients with advanced HCC. Despite these major advances, a better molecular and cellular characterization of the tumor microenvironment is still needed because it has a crucial role in the development and progression of HCC. Inflamed (hot) and noninflamed (cold) HCC tumors and genomic signatures have been associated with response to ICIs. However, there are no additional biomarkers to guide clinical decision-making. Other immune-targeting strategies, such as adoptive T-cell transfer, vaccination, and virotherapy, are currently under development. This review provides an overview on the HCC immune microenvironment, different cellular players, current available immunotherapies, and potential immunotherapy modalities.

Interplay between plasmacytoid dendritic cells and tumor-specific T cells in peripheral blood influences long-term survival in non-small cell lung carcinoma

Plasmacytoid dendritic cells (pDCs) represent a subset of antigen-presenting cells that play an ambivalent role in cancer immunity. Here, we investigated the clinical significance of circulating pDCs and their interaction with tumor-specific T cell responses in patients with non-small cell lung cancer (NSCLC, n = 126) . The relation between intratumoral pDC signature and immune checkpoint inhibitors efficacy was also evaluated. Patients with NSCLC had low level but activated phenotype pDC compared to healthy donors. In overall population, patients with high level of pDC (pDC^high) had improved overall survival (OS) compared to patients with pDC^low, median OS 30.4 versus 20.7 months (P = 0.013). This clinical benefit was only observed in stage I to III patients, but not in metastatic disease. We showed that patients harboring pDC^high profile had high amount of Th1-diffentiation cytokine interleukin-12 (IL-12) in blood and had functional T cells directed against a broad range of tumor antigens. Furthermore, a high pDC signature in the tumor microenvironment was associated with improved clinical outcome in patients treated with anti-PD-(L)1 therapy. Overall, this study showed that circulating pDC^high is associated with long-term OS in NSCLC and highlighted the predictive value of intratumor pDC signature in the efficacy of immune checkpoint inhibitors.

Peroxisome-related genes in hepatocellular carcinoma correlated with tumor metabolism and overall survival

BACKGROUND AND AIM

A prominent hallmark of tumors is aberrant lipid metabolism, and various peroxisome-related genes (PRGs) are associated with aberrant tumoral metabolic signaling. However, the influence of PRGs on the prognosis of hepatocellular carcinoma (HCC) patients remains debatable. Thus, the current study was designed to evaluate the effect of PRGs on HCC and construct a prognostic model for predicting survival.

METHODS

We initially acquired HCC-related gene expression profiles from the Cancer Genome Atlas and International Cancer Genome Consortium databases. We then utilized Cox analysis and Lasso regression to identify suitable PRGs for the risk model. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to clarify the functional roles of PRGs. Single-sample gene set enrichment analysis (ssGSEA) was conducted to confirm the relationship between PRGs and immunity.

RESULTS

Four PRGs were correlated with HCC patient survival: 2 risk genes (MPV17, and ABCD1) and 2 protective genes (ACSL1 and ACSL6). We derived risk scores based on PRGs to construct a predictive model that could accurately predict overall survival (OS) among HCC patients. Furthermore, GO and KEGG analyses revealed that these PRGs were potentially involved in lipid metabolism and ferroptosis in HCC. Moreover, ssGSEA results demonstrated that high PRG scores were associated with immune suppressor activation, which caused the suppression of immune effectors (CD8⁺ T-cells, B cells, and NK cells) and the attenuation of the immune-mediated antitumor effect.

CONCLUSION

PRGs act as key regulators in tumorigenesis and tumor progression by affecting lipid synthesis and utilization, which we used to predict the outcome of HCC patients. Moreover, PRGs have been shown to promote tumoral immune resistance by serving as a vital bridge between metabolism and immunity. Thus, a personalized treatment approach targeting PRGs would clinically benefit patients by blocking the interaction between tumor metabolism and immunity.

Sorafenib inhibits interferon production by plasmacytoid dendritic cells in hepatocellular carcinoma

BACKGROUND

Sorafenib is a multi-kinase inhibitor that shows antitumor activity in advanced hepatocellular carcinoma. Sorafenib exerts a regulatory effect on immune cells, including T cells, natural killer cells and dendritic cells. Studies have shown that plasmacytoid dendritic cells (pDCs) are functionally impaired in cancer tissues or produce low type I interferon alpha (IFNα) in cancer microenvironments. However, the effects of sorafenib on the function of pDCs have not been evaluated in detail.

METHODS

Normal and patient PBMCs were stimulated with CpG-A to evaluate IFNα production with Flow cytometry and ELISA.

RESULT

We analyzed the production of IFNα by PBMCs in patients with advanced HCC under sorafenib treatment. We found that sorafenib-treated HCC patients produced less IFNα than untreated patients. Furthermore, we demonstrated that sorafenib suppressed the production of IFNα by PBMCs or pDCs from heathy donors in a concentration-dependent manner.

CONCLUSION

Sorafenib suppressed pDCs function. Given that sorafenib is a currently recommended targeted therapeutic agent against cancer, our results suggest that its immunosuppressive effect on pDCs should be considered during treatment.

Dendritic cell-based cancer immunotherapy in the era of immune checkpoint inhibitors: From bench to bedside

Dendritic cells (DCs) can present tumoral antigens to T-cells and stimulate T-cell-mediated anti-tumoral immune responses. In addition to uptaking, processing, and presenting tumoral antigens to T-cells, co-stimulatory signals have to be established between DCs with T-cells to develop anti-tumoral immune responses. However, most of the tumor-infiltrated immune cells are immunosuppressive in the tumor microenvironment (TME), paving the way for immune evasion of tumor cells. This immunosuppressive TME has also been implicated in suppressing the DC-mediated anti-tumoral immune responses, as well. Various factors, i.e., immunoregulatory cells, metabolic factors, tumor-derived immunosuppressive factors, and inhibitory immune checkpoint molecules, have been implicated in developing the immunosuppressive TME. Herein, we aimed to review the biology of DCs in developing T-cell-mediated anti-tumoral immune responses, the significance of immunoregulatory cells in the TME, metabolic barriers contributing to DCs dysfunction in the TME, tumor-derived immunosuppressive factors, and inhibitory immune checkpoint molecules in DC-based cell therapy outcomes. With reviewing the ongoing clinical trials, we also proposed a novel therapeutic strategy to increase the efficacy of DC-based cell therapy. Indeed, the combination of DC-based cell therapy with monoclonal antibodies against novel immune checkpoint molecules can be a promising strategy to increase the response rate of patients with cancers.

Tumor: Stroma Interaction and Cancer

The understanding of how normal cells transform into tumor cells and progress to invasive cancer and metastases continues to evolve. The tumor mass is comprised of a heterogeneous population of cells that include recruited host immune cells, stromal cells, matrix components, and endothelial cells. This tumor microenvironment plays a fundamental role in the acquisition of hallmark traits, and has been the intense focus of current research. A key regulatory mechanism triggered by these tumor-stroma interactions includes processes that resemble epithelial-mesenchymal transition, a physiologic program that allows a polarized epithelial cell to undergo biochemical and cellular changes and adopt mesenchymal cell characteristics. These cellular adaptations facilitate enhanced migratory capacity, invasiveness, elevated resistance to apoptosis, and greatly increased production of ECM components. Indeed, it has been postulated that cancer cells undergo epithelial-mesenchymal transition to invade and metastasize.In the following discussion, the physiology of chronic inflammation, wound healing, fibrosis, and tumor invasion will be explored. The key regulatory cytokines, transforming growth factor β and osteopontin, and their roles in cancer metastasis will be highlighted.

The Therapeutic Potential of Tackling Tumor-Induced Dendritic Cell Dysfunction in Colorectal Cancer

Colorectal cancer (CRC) is the third most diagnosed malignancy and the second leading cause of cancer-related deaths worldwide. Locally advanced and metastatic disease exhibit resistance to therapy and are prone to recurrence. Despite significant advances in standard of care and targeted (immuno)therapies, the treatment effects in metastatic CRC patients have been modest. Untreatable cancer metastasis accounts for poor prognosis and most CRC deaths. The generation of a strong immunosuppressive tumor microenvironment (TME) by CRC constitutes a major hurdle for tumor clearance by the immune system. Dendritic cells (DCs), often impaired in the TME, play a critical role in the initiation and amplification of anti-tumor immune responses. Evidence suggests that tumor-mediated DC dysfunction is decisive for tumor growth and metastasis initiation, as well as for the success of immunotherapies. Unravelling and understanding the complex crosstalk between CRC and DCs holds promise for identifying key mechanisms involved in tumor progression and spread that can be exploited for therapy. The main goal of this review is to provide an overview of the current knowledge on the impact of CRC-driven immunosuppression on DCs phenotype and functionality, and its significance for disease progression, patient prognosis, and treatment response. Moreover, present knowledge gaps will be highlighted as promising opportunities to further understand and therapeutically target DC dysfunction in CRC. Given the complexity and heterogeneity of CRC, future research will benefit from the use of patient-derived material and the development of in vitro organoid-based co-culture systems to model and study DCs within the CRC TME.

Neuroinflammation in Autoimmune Disease and Primary Brain Tumors: The Quest for Striking the Right Balance

According to classical dogma, the central nervous system (CNS) is defined as an immune privileged space. The basis of this theory was rooted in an incomplete understanding of the CNS microenvironment, however, recent advances such as the identification of resident dendritic cells (DC) in the brain and the presence of CNS lymphatics have deepened our understanding of the neuro-immune axis and revolutionized the field of neuroimmunology. It is now understood that many pathological conditions induce an immune response in the CNS, and that in many ways, the CNS is an immunologically distinct organ. Hyperactivity of neuro-immune axis can lead to primary neuroinflammatory diseases such as multiple sclerosis and antibody-mediated encephalitis, whereas immunosuppressive mechanisms promote the development and survival of primary brain tumors. On the therapeutic front, attempts are being made to target CNS pathologies using various forms of immunotherapy. One of the most actively investigated areas of CNS immunotherapy is for the treatment of glioblastoma (GBM), the most common primary brain tumor in adults. In this review, we provide an up to date overview of the neuro-immune axis in steady state and discuss the mechanisms underlying neuroinflammation in autoimmune neuroinflammatory disease as well as in the development and progression of brain tumors. In addition, we detail the current understanding of the interactions that characterize the primary brain tumor microenvironment and the implications of the neuro-immune axis on the development of successful therapeutic strategies for the treatment of CNS malignancies.

Alpha-Fetoprotein- and CD40Ligand-Expressing Dendritic Cells for Immunotherapy of Hepatocellular Carcinoma

Simple Summary

In first clinical trials, vaccinations against tumor-associated antigens (TAA), such as Alpha-Fetoprotein (AFP) using antigen presenting cells, such as dendritic cells (DC), failed to achieve effective immune responses towards hepatocellular carcinoma (HCC). CD40Ligand is a potent immune checkpoint, which can increase the antitumoral immune response of DC. In this study, a subcutaneous vaccination with DCs, which were transduced with AFP-coding adenoviruses and an intratumoral treatment with DCs, which were transduced with CD40L-coding adenoviruses, induced an antitumoral immune response and led to complete remissions and long-term survival in 62% of mice with established HCC. Combined strategy causes rapid and profound changes in the tumor environment with enhanced Th1-cytokine expression, strong tumor infiltration of cytotoxic T lymphocytes and DC, and higher tumor apoptosis, leading to effective tumor regression of HCC. Thus, intratumoral CD40L co-stimulation represents a promising tool for improving tumor-antigen DC-based immunotherapy of HCC.

Abstract

Dendritic cells (DC) as professional antigen presenting cells are able to prime T-cells against the tumor-associated antigen α-fetoprotein (AFP) for immunotherapy of hepatocellular carcinoma (HCC). However, a strong immunosuppressive tumor environment limits their efficacy in patients. The co-stimulation with CD40Ligand (CD40L) is critical in the maturation of DC and T-cell priming. In this study, the impact of intratumoral (i.t.) CD40L-expressing DC to improve vaccination with murine (m)AFP-transduced DC (Ad-mAFP-DC) was analyzed in subcutaneous (s.c.) and orthotopic murine HCC. Murine DC were adenovirally transduced with Ad-mAFP or Ad-CD40L. Hepa129-mAFP-cells were injected into the right flank or the liver of C3H-mice to induce subcutaneous (s.c.) and orthotopic HCC. For treatments, 10⁶ Ad-mAFP-transduced DC were inoculated s.c. followed by 10⁶ CD40L-expressing DC injected intratumorally (i.t.). S.c. inoculation with Ad-mAFP-transduced DC, as vaccine, induced a delay of tumor-growth of AFP-positive HCC compared to controls. When s.c.-inoculation of Ad-mAFP-DC was combined with i.t.-application of Ad-CD40L-DC synergistic antitumoral effects were observed and complete remissions and long-term survival in 62% of tumor-bearing animals were achieved. Analysis of the tumor environment at different time points revealed that s.c.-vaccination with Ad-mAFP-DC seems to stimulate tumor-specific effector cells, allowing an earlier recruitment of effector T-cells and a Th1 shift within the tumors. After i.t. co-stimulation with Ad-CD40L-DC, production of Th1-cytokines was strongly increased and accompanied by a robust tumor infiltration of mature DC, activated CD4⁺-, CD8⁺-T-cells as well as reduction of regulatory T-cells. Moreover, Ad-CD40L-DC induced tumor cell apoptosis. Intratumoral co-stimulation with CD40L-expressing DC significantly improves vaccination with Ad-mAFP-DC in pre-established HCC in vivo. Combined therapy caused an early and strong Th1-shift in the tumor environment as well as higher tumor apoptosis, leading to synergistic tumor regression of HCC. Thus, CD40L co-stimulation represents a promising tool for improving DC-based immunotherapy of HCC.

Insights Into Dendritic Cells in Cancer Immunotherapy: From Bench to Clinical Applications

Dendritic cells (DCs) are efficient antigen-presenting cells (APCs) and potent activators of naïve T cells. Therefore, they act as a connective ring between innate and adaptive immunity. DC subsets are heterogeneous in their ontogeny and functions. They have proven to potentially take up and process tumor-associated antigens (TAAs). In this regard, researchers have developed strategies such as genetically engineered or TAA-pulsed DC vaccines; these manipulated DCs have shown significant outcomes in clinical and preclinical models. Here, we review DC classification and address how DCs are skewed into an immunosuppressive phenotype in cancer patients. Additionally, we present the advancements in DCs as a platform for cancer immunotherapy, emphasizing the technologies used for in vivo targeting of endogenous DCs, ex vivo generated vaccines from peripheral blood monocytes, and induced pluripotent stem cell-derived DCs (iPSC-DCs) to boost antitumoral immunity.

Natural Killer-Dendritic Cell Interactions in Liver Cancer: Implications for Immunotherapy

Simple Summary

The reciprocal crosstalk between dendritic cells (DCs) and natural killer (NK) cells plays a pivotal role in regulating immune defense against viruses and tumors. The Th-cell polarizing ability, cytokine-producing capacity, chemokine expression, and migration of DCs are regulated by activated NK cells. Conversely, the effector functions including lysis and cytokine production, proliferation, and migration of NK cells are influenced by close interactions with activated DCs. In this review, we explore the impact of DC–NK cell crosstalk and its therapeutic potential in immune control of liver malignances.

Abstract

Natural killer (NK) and dendritic cells (DCs) are innate immune cells that play a crucial role in anti-tumor immunity. NK cells kill tumor cells through direct cytotoxicity and cytokine secretion. DCs are needed for the activation of adaptive immune responses against tumor cells. Both NK cells and DCs are subdivided in several subsets endowed with specialized effector functions. Crosstalk between NK cells and DCs leads to the reciprocal control of their activation and polarization of immune responses. In this review, we describe the role of NK cells and DCs in liver cancer, focusing on the mechanisms involved in their reciprocal control and activation. In this context, intrahepatic NK cells and DCs present unique immunological features, due to the constant exposure to non-self-circulating antigens. These interactions might play a fundamental role in the pathology of primary liver cancer, namely hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). Additionally, the implications of these immune changes are relevant from the perspective of improving the cancer immunotherapy strategies in HCC and ICC patients.

"Complimenting the Complement": Mechanistic Insights and Opportunities for Therapeutics in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and a leading cause of death in the US and worldwide. HCC remains a global health problem and is highly aggressive with unfavorable prognosis. Even with surgical interventions and newer medical treatment regimens, patients with HCC have poor survival rates. These limited therapeutic strategies and mechanistic understandings of HCC immunopathogenesis urgently warrant non-palliative treatment measures. Irrespective of the multitude etiologies, the liver microenvironment in HCC is intricately associated with chronic necroinflammation, progressive fibrosis, and cirrhosis as precedent events along with dysregulated innate and adaptive immune responses. Central to these immunological networks is the complement cascade (CC), a fundamental defense system inherent to the liver which tightly regulates humoral and cellular responses to noxious stimuli. Importantly, the liver is the primary source for biosynthesis of >80% of complement components and expresses a variety of complement receptors. Recent studies implicate the complement system in liver inflammation, abnormal regenerative responses, fibrosis, carcinogenesis, and development of HCC. Although complement activation differentially promotes immunosuppressive, stimulant, and angiogenic microenvironments conducive to HCC development, it remains under-investigated. Here, we review derangement of specific complement proteins in HCC in the context of altered complement regulatory factors, immune-activating components, and their implications in disease pathogenesis. We also summarize how complement molecules regulate cancer stem cells (CSCs), interact with complement-coagulation cascades, and provide therapeutic opportunities for targeted intervention in HCC.

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.

The Protein Secretome Is Altered in Rectal Cancer Tissue Compared to Normal Rectal Tissue, and Alterations in the Secretome Induce Enhanced Innate Immune Responses

Simple Summary

Rectal cancer occurs in the lower part of the bowel, and approximately half of all rectal cancer patients receive chemoradiotherapy before surgery. In ~22% of cases the tumour is eradicated, but the reasons for different response rates between patients are largely unknown. Inflammation and the immune system are important players in the response to cancer treatment, but we do not fully understand the role they play in this clinical setting. We examined the levels of 54 inflammatory markers in normal (non-cancerous) rectal tissue and rectal cancer tissue, and we found that rectal cancer tissue was more inflammatory, and the levels of inflammatory markers correlated with obesity status. We found that irradiating rectal cancer tissue enhanced the ability of immune cells to induce an anti-tumour immune response.

Abstract

Locally advanced rectal cancer is treated with neoadjuvant-chemoradiotherapy; however, only ~22% of patients achieve a complete response, and resistance mechanisms are poorly understood. The role of inflammation and immune cell biology in this setting is under-investigated. In this study, we profiled the inflammatory protein secretome of normal (non-cancer) (n = 8) and malignant rectal tissue (n = 12) pre- and post-radiation in human ex vivo explant models and examined the influence of these untreated and treated secretomes on dendritic cell biology (n = 8 for cancer and normal). These resultant profiles were correlated with patient clinical characteristics. Nineteen factors were secreted at significantly higher levels from the rectal cancer secretome when compared to the normal rectal secretome; Flt-1, P1GF, IFN-γ, IL-6, IL-10, CCL20, CCL26, CCL22, CCL3, CCL4, CCL17, GM-CSF, IL-12/IL-23p40, IL-17A, IL-1α, IL-17A/F, IL-1RA, TSLP and CXCL10 (p < 0.05). Radiation was found to have differential effects on normal rectal tissue and rectal cancer tissue with increased IL-15 and CCL22 secretion following radiation from normal rectal tissue explants (p < 0.05), while no significant alterations were observed in the irradiated rectal cancer tissue. Interestingly, however, the irradiated rectal cancer secretome induced the most potent effect on dendritic cell maturation via upregulation of CD80 and PD-L1. Patient’s visceral fat area correlated with secreted factors including CCL20, suggesting that obesity status may alter the tumour microenvironment (TME). These results suggest that radiation does not have a negative effect on the ability of the rectal cancer TME to induce an immune response. Understanding these responses may unveil potential therapeutic targets to enhance radiation response and mitigate normal tissue injury. Tumour irradiation in this cohort enhances innate immune responses, which may be harnessed to improve patient treatment outcome.

High PD-L1/CD274 Expression of Monocytes and Blood Dendritic Cells Is a Risk Factor in Lung Cancer Patients Undergoing Treatment with PD1 Inhibitor Therapy

Simple Summary

Tumor cells can evade destruction via immune cells by expressing coinhibitory membrane molecules, which suppress antitumoral immune responses. Immune checkpoint inhibitor therapy acts by blocking these inhibitory pathways. Although this type of immunotherapy has shown promising results for selected cancer patients during recent years, an important challenge remains to identify baseline characteristics of patients who will mostly benefit from such therapy. The aim of our study was to assess the expression of the coinhibitory molecule PD-L1/CD274 on different antigen-presenting cells (monocytes and dendritic cell subsets) in the peripheral blood of 35 patients with nonsmall cell lung cancer undergoing checkpoint inhibitor therapy. CD274 expression correlated with therapy response and the survival of patients. Tumor patients with high CD274 expression levels of antigen-presenting cells in blood rarely responded to checkpoint inhibitor therapy. Our results implicate that a high CD274 expression in monocytes and dendritic cell subsets is a risk factor for therapy response.

Abstract

The aim of this study was to investigate the expression of the coinhibitory molecule PD-L1/CD274 in monocytes and dendritic cells (DC) in the blood of lung cancer patients undergoing PD1 inhibitor therapy and to correlate data with patient’s outcome. PD-L1/CD274 expression of monocytes, CD1c⁺ myeloid DC (mDC) and CD303⁺ plasmacytoid DC (pDC) was determined by flow cytometry in peripheral blood at immunotherapy onset. The predictive value of the PD-L1/CD274-expression data was determined by patients’ survival analysis. Patients with a high PD-L1/CD274 expression of monocytes and blood DC subpopulations rarely responded to PD1 inhibitor therapy. Low PD-L1/CD274 expression of monocytes and DC correlated with prolonged progression-free survival (PFS) as well as overall survival (OS). The highest PD-L1/CD274 expression was found in CD14⁺HLA-DR⁺⁺CD16⁺ intermediate monocytes. Whereas the PD-L1/CD274 expression of monocytes and DC showed a strong positive correlation, only the PD-L1/CD274 expression of DC inversely correlated with DC amounts and lymphocyte counts in peripheral blood. Our results implicate that a high PD-L1/CD274 expression of blood monocytes and DC subtypes is a risk factor for therapy response and for the survival of lung cancer patients undergoing PD1 inhibitor therapy.

Human Plasmacytoid Dendritic Cells and Cutaneous Melanoma

The prognosis of metastatic melanoma (MM) patients has remained poor for a long time. However, the recent introduction of effective target therapies (BRAF and MEK inhibitors for BRAFV600-mutated MM) and immunotherapies (anti-CTLA-4 and anti-PD-1) has significantly improved the survival of MM patients. Notably, all these responses are highly dependent on the fitness of the host immune system, including the innate compartment. Among immune cells involved in cancer immunity, properly activated plasmacytoid dendritic cells (pDCs) exert an important role, bridging the innate and adaptive immune responses and directly eliminating cancer cells. A distinctive feature of pDCs is the production of high amount of type I Interferon (I-IFN), through the Toll-like receptor (TLR) 7 and 9 signaling pathway activation. However, published data indicate that melanoma-associated escape mechanisms are in place to hijack pDC functions. We have recently reported that pDC recruitment is recurrent in the early phases of melanoma, but the entire pDC compartment collapses over melanoma progression. Here, we summarize recent advances on pDC biology and function within the context of melanoma immunity.

Suppression of TGF-β and IL-10 receptors on self-differentiated dendritic cells by short-hairpin RNAs enhanced activation of effector T-cells against cholangiocarcinoma cells

Cholangiocarcinoma (CCA) is an aggressive tumor that is associated with high rates of recurrence and mortality. This is due, in part, to the fact that CCA cells and their microenvironment secrete immunosuppressive cytokines, transforming growth factor-β (TGF-β) and interleukin-10 (IL-10), that inhibit dendritic cell (DC) functions, which, in turn, results in the decreased anti-tumor activity of T-cells. We hypothesized that the TGF-β receptor and IL-10 blockade on dendritic cells would improve DC function, thereby allowing improved activation of T cells against CCA cells. To test our hypothesis, we generated self-differentiated DCs (SD-DCs) via transduction of human peripheral blood monocytes with lentivirus expressing IL-4 and GM-CSF. SD-DCs were transduced with a second lentivirus containing short-hairpin RNAs (shRNAs) to knock-down TGF-βRII and IL-10RA mRNAs. Immunoblot confirmed the reduced expression levels of TGF-β and IL-10 receptors in both SD-DCs that were transduced with a single and/or combination of lentiviruses containing shRNAs. SD-DCs were thereafter pulsed with tumor antigens extracted from CCA cell lines in an effort to activate DC function. MHC class II (HLA-DR) and co-stimulatory molecules (CD40 and CD86) on SD-DCs were upregulated to levels comparable to those on DCs generated by the conventional method. Suppression of TGF-β and IL-10 receptors on SD-DCs influenced the effector T-cells to produce IFN-γ, which enhanced their ability to kill CCA cells. The preparation of adoptive effector T-cells holds the potential of becoming a novel therapy for cellular immunotherapy in CCA.

The systemic inflammatory response as a source of biomarkers and therapeutic targets in hepatocellular carcinoma

The pathogenesis of hepatocellular carcinoma (HCC) strongly relates to inflammation, with chronic up-regulation of pro-inflammatory mediators standing as a potential unifying mechanism that underscores the origin and progression of HCC independent of aetiology. Activation of the diverse pro-inflammatory mediators either within the tumour or its microenvironment is part of an active cross-talk between the progressive HCC and the host, which is known to influence clinical outcomes including recurrence after radical treatments and long-term survival. A number of clinical biomarkers to measure the severity of cancer-related inflammation are now available, most of which emerge from routine blood parameters including neutrophil, lymphocyte, platelet counts, as well as albuminaemia and C-reactive protein levels. In this review, we summarise the body of evidence supporting the biologic qualification of inflammation-based scores in HCC and review their potential in facilitating the prognostic assessment and treatment allocation in the individual patient. We also discuss the evidence to suggest modulation of tumour-promoting inflammation may act as a source of novel therapeutic strategies in liver cancer.

Dendritic cell subsets and locations

Dendritic cells (DCs) are a unique class of immune cells that act as a bridge between innate and adaptive immunity. The discovery of DCs by Cohen and Steinman in 1973 laid the foundation for DC biology, and the advances in the field identified different versions of DCs with unique properties and functions. DCs originate from hematopoietic stem cells, and their differentiation is modulated by Flt3L. They are professional antigen-presenting cells that patrol the environmental interphase, sites of infection, or infiltrate pathological tissues looking for antigens that can be used to activate effector cells. DCs are critical for the initiation of the cellular and humoral immune response and protection from infectious diseases or tumors. DCs can take up antigens using specialized surface receptors such as endocytosis receptors, phagocytosis receptors, and C type lectin receptors. Moreover, DCs are equipped with an array of extracellular and intracellular pattern recognition receptors for sensing different danger signals. Upon sensing the danger signals, DCs get activated, upregulate costimulatory molecules, produce various cytokines and chemokines, take up antigen and process it and migrate to lymph nodes where they present antigens to both CD8 and CD4 T cells. DCs are classified into different subsets based on an integrated approach considering their surface phenotype, expression of unique and conserved molecules, ontogeny, and functions. They can be broadly classified as conventional DCs consisting of two subsets (DC1 and DC2), plasmacytoid DCs, inflammatory DCs, and Langerhans cells.

IL-10 promoter hypomethylation is associated with increased IL-10 expression and poor survival in hepatocellular carcinoma

Background

Epigenetic alterations of tumor-associated genes contribute to the pathogenesis of virtually all cancer types. We evaluated the methylation status of the interleukin-10 (IL-10) gene promoter and assessed its association with IL-10 mRNA expression and clinical prognosis in hepatocellular carcinoma (HCC) patients.

Methods

Methylation-specific polymerase chain reaction (MSP) and real-time polymerase chain reaction (PCR) were used to define the methylation index (MI) of the IL-10 gene and quantify IL-10 mRNA expression in 120 HCC samples and paired non-tumor tissues.

Results

Mean MI was 0.47 in HCC specimens and 0.59 in non-tumor controls, and was associated with metastasis classification and serum α-fetoprotein (AFP) levels. IL-10 mRNA levels [mean –∆∆Ct of 1.678 in HCC cases with hypomethylation (∆MI ≤0) and –0.18 in HCC cases with hypermethylation (∆MI >0)] also correlated with metastasis classification and serum AFP. An association was detected between IL-10 mRNA and its gene’s MI in HCC. Also, an association was found between IL-10 hypomethylation, but not IL-10 mRNA expression and reduced postoperative HCC survival.

Conclusions

These results indicate that IL-10 promoter hypomethylation is associated with increased IL-10 mRNA levels and indicative of poor survival in HCC.

A combined treatment of curcumin, piperine, and taurine alters the circulating levels of IL-10 and miR-21 in hepatocellular carcinoma patients: a pilot study

Background

Investigating and evaluating possible alternative therapeutic strategies to control hepatocellular carcinoma (HCC) is a critical need because of its high prevalence and being one of the most lethal cancers. Curcumin and taurine showed potent anti-tumor activities in pre-clinical and clinical studies by targeting multiple pathways. Thus, this study was designed to assess the effect of a combined treatment consisted of curcumin, piperine, and taurine on circulating levels of interleukin-10 (IL-10), and microRNAs miR-141 and miR-21.

Methods

Twenty eligible HCC patients administrated an oral dose of 4 g curcumin, 40 mg piperine, and 500 mg taurine daily for three successive treatment cycles, each was a 30-day. The level of IL-10 along with the expression levels of miR-141, and miR-21 were monitored in serum before starting the treatment and after each cycle. Patients were followed-up for a period of 24 months.

Results

The combined treatment was able to produce a significant decrease in the levels of serum IL-10, and miR-21 while it resulted in a non-significant up-regulation of serum miR-141 expression level. At the end of the follow-up period, the median overall survival (OS) rate was found to be 17.00 months with a worse OS in patients with high baseline levels of circulating IL-10 and miR-21 compared to those with low levels. In contrast, a low baseline level of circulating miR-141 was associated with poor prognosis.

Conclusions

The combined treatment may be able to increase the OS rate by altering the circulating level of IL-10 and miR-21.

Diagnostic and therapeutic potential of the gut microbiota in patients with early hepatocellular carcinoma

The gut microbiota is involved in the maintenance of the homeostasis of the human body and its alterations are associated with the development of different pathological conditions. The liver is the organ most exposed to the influence of the gut microbiota, and recently important connections between the intestinal flora and hepatocellular carcinoma (HCC) have been described. In fact, HCC is commonly associated with liver cirrhosis and develops in a microenvironment where inflammation, immunological alterations, and cellular aberrations are dramatically evident. Prevention and diagnosis in the earliest stages are still the most effective weapons in fighting this tumor. Animal models show that the gut microbiota can be involved in the promotion and progression of HCC directly or through different pathogenic mechanisms. Recent data in humans have confirmed these preclinical findings, shedding new light on HCC pathogenesis. Limitations due to the different experimental design, the ethnic and hepatological setting make it difficult to compare the results and draw definitive conclusions, but these studies lay the foundations for a pathogenetic redefinition of HCC. Therefore, it is evident that the characterization of the gut microbiota and its modulation can have an enormous diagnostic, preventive, and therapeutic potential, especially in patients with early stage HCC.

Tumor-Derived α-Fetoprotein Suppresses Fatty Acid Metabolism and Oxidative Phosphorylation in Dendritic Cells

Cellular metabolism supports immune cell function. Here, we identify a reduction in fatty acid synthesis and mitochondrial metabolism in dendritic cells (DC) due to α-fetoprotein (AFP), a protein secreted by hepatocellular cancer (HCC). DCs cultured in the presence of AFP show reduced expression of the metabolic regulatory molecules SREBP-1 and PGC1-α. The negative effect of AFP on mitochondrial metabolism and ATP production was confirmed with observation of reduction in basal oxygen consumption rate (OCR) in DCs exposed to AFP derived from cord blood. More severe reduction in basal OCR was observed in tumor-derived DCs exposed to AFP due to downregulation of cytochrome c oxidase. We also showed reduced expression of PGC1-α in circulating myeloid DCs of patients with HCC and impaired capacity to stimulate antigen-specific effector functions. These data show the negative effects of AFP on DC metabolism. These findings elucidate a mechanism of immune suppression in HCC and may help generate therapeutic approaches to reverse such immunosuppression.

Serum Levels of APRIL Increase in Patients with Glioma, Meningioma and Schwannoma

Objective:

Brain tumors are of high mortality and morbidity for which there is still no cure. The TNF family cytokine, A Proliferation Inducing Ligand (APRIL), is shown to help proliferation and development of tumor cells. We assessed serum levels of APRIL in patients with glioma, meningioma and schwannoma in comparison to healthy individuals.

Methods:

Peripheral blood samples of 68 patients with brain tumors, divided into three groups of gliomas (n=25), meningiomas (n=30) and schwannomas (n=13), as well as 45 healthy individuals were obtained. Serum samples were prepared and stored in -40°C until usage. Using a commercial ELISA method, APRIL concentration was measured in each serum sample. The obtained data were then analyzed using SPSS software.

Results:

APRIL serum levels were higher in all patients compared to the controls (P<0.001). Moreover, APRIL serum levels were higher in each of the tumor bearing groups (gliomas, meningiomas and schwannomas) in comparison to the controls (P<0.001, <0.001 and =0.001, respectively). Comparing APRIL between the patients groups showed no significant difference. Age and gender showed no significant correlation with serum APRIL levels, although the age of patients in glioma group was significantly lower than controls (P=0.017). The serum APRIL levels in gliomas with histological grade showed no difference, but in meningiomas, it was lower in tumors with higher grades (P= 0.011).

Conclusion:

Increased serum levels of APRIL in patients with meningioma and schwannoma as well as glioma may indicate a common role of this cytokine in brain tumors.

Plasmodium falciparum Activates CD16+ Dendritic Cells to Produce Tumor Necrosis Factor and Interleukin-10 in Subpatent Malaria

Background

The malaria causing parasite Plasmodium subverts host immune responses by several strategies including the modulation of dendritic cells (DCs).

Methods

In this study, we show that Plasmodium falciparum skewed CD16+ DC cytokine responses towards interleukin (IL)-10 production in vitro, distinct to the cytokine profile induced by Toll-like receptor ligation. To determine CD16+ DC responsiveness in vivo, we assessed their function after induced P falciparum infection in malaria-naive volunteers.

Results

CD16+ DCs underwent distinctive activation, with increased expression of maturation markers human leukocyte antigen (HLA)-DR and CD86, enhanced tumor necrosis factor (TNF) production, and coproduction of TNF/IL-10. In vitro restimulation with P falciparum further increased IL-10 production. In contrast, during naturally acquired malaria episode, CD16+ DCs showed diminished maturation, suggesting increased parasite burden and previous exposure influence DC subset function.

Conclusions

These findings identify CD16+ DCs as the only DC subset activated during primary blood-stage human Plasmodium infection. As dual cytokine producers, CD16+ DCs contribute to inflammatory as well as regulatory innate immune processes.

Does the Immunocompetent Status of Cancer Patients Have an Impact on Therapeutic DC Vaccination Strategies?

Although different types of therapeutic vaccines against established cancerous lesions in various indications have been developed since the 1990s, their clinical benefit is still very limited. This observed lack of effectiveness in cancer eradication may be partially due to the often deficient immunocompetent status of cancer patients, which may facilitate tumor development by different mechanisms, including immune evasion. The most frequently used cellular vehicle in clinical trials are dendritic cells (DCs), thanks to their crucial role in initiating and directing immune responses. Viable vaccination options using DCs are available, with a positive toxicity profile. For these reasons, despite their limited therapeutic outcomes, DC vaccination is currently considered an additional immunotherapeutic option that still needs to be further explored. In this review, we propose potential actions aimed at improving DC vaccine efficacy by counteracting the detrimental mechanisms recognized to date and implicated in establishing a poor immunocompetent status in cancer patients.

Reduced CD160 Expression Contributes to Impaired NK-cell Function and Poor Clinical Outcomes in Patients with HCC

: We previously reported that deficiencies in natural killer (NK)-cell number and function play an important role in the progression of hepatocellular carcinoma (HCC). However, the mechanisms underlying this phenomenon remain obscure. In this study, we analyzed the expression of CD160 on intrahepatic NK cells by evaluating peritumoral and intratumoral tissues of 279 patients with HCC and 20 healthy livers. We observed reduced expression of CD160 on intratumoral NK cells, and patients with lower CD160 cell densities within tumors exhibited worse disease and a higher recurrence rate. High-resolution microarray and gene set enrichment analysis of flow cytometry-sorted primary intrahepatic CD160⁺ and CD160^- NK cells of healthy livers indicated that human CD160⁺ NK cells exhibited functional activation, high IFNγ production, and NK-mediated immunity. In addition, global transcriptomic analysis of sorted peritumoral and intratumoral CD160⁺ NK cells revealed that intratumoral CD160⁺ NK cells are more exhausted than peritumoral CD160⁺ NK cells and produce less IFNγ. High levels of TGFβ1 interfered with production of IFNγ by CD160⁺ NK cells, blocking of which specifically restored IFNγ production in CD160⁺ NK cells to normal levels. These findings indicate that reduced numbers of CD160⁺ NK cells, together with the functional impairment of CD160⁺ NK cells by TGFβ1, contribute to tumor immune escape. In addition, restoring the expression of CD160 and blocking TGFβ1 appear a promising therapeutic strategy against liver cancer. SIGNIFICANCE: These findings show that reduced number and function of CD160⁺ NK cells in the tumor microenvironment contributes to immune escape of HCC; blocking TGFβ1 restores IFNγ production of CD160⁺ NK cells.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/23/6581/F1.large.jpg.

Inhibition of IL-10 and TGF-β receptors on dendritic cells enhances activation of effector T-cells to kill cholangiocarcinoma cells

Tumor escapes host immune responses by producing immunosuppressive cytokines, such as IL-10 and TGF-β, secreted into the tumor microenvironment. These cytokines play important roles in the suppression of dendritic cell (DC) function, leading to decreased immune responses of the effector CD4⁺ and CD8⁺ T cells. To improve DC functions and enhance cytolytic activity of activated effector T-cells, we suppressed the effect of these cytokines on DCs by using specific neutralizing antibodies that inhibit IL-10 and TGF-β receptors. Monocyte-derived DCs generated in vitro showed up-regulation of MHC (HLA-DR) and co-stimulatory molecules (CD40 and CD86). The IL-10 and TGF-β receptors were expressed and localized on cell membrane of DCs, as shown by Western blot analysis and immunofluorescence staining, whereas the IL-10 and TGF-β ligands were detected in the culture supernatants of DCs and cholangiocarcinoma (CCA) cell line, respectively. Inhibition of the IL-10 and TGF-β receptors on DCs by specific neutralizing antibodies significantly increased level of IFN-γ and enhanced cytolytic activity of the DC-activated effector T-cells against CCA cell line. These results indicate that the IL-10 and TGF-β receptors are the targets for inhibition to increase DC functions and enhance cytolytic activity of the DC-activated effector T-cells against CCA cells. Thus, inhibition of the IL-10 and TGF-β receptors on DCs is crucial in the preparation of DC-activated effector T cells for adoptive T-cell therapy.

Evaluation of serum interleukin-10 levels in hepatocellular carcinoma patients: a systematic review and meta-analysis

Aim of the study

This meta-analysis aimed to evaluate serum IL-10 levels in HCC patients.

Material and methods

The three databases PubMed, Scopus and Web of Science were checked on July 2017 for assessment of IL-10 levels in hepatocellular carcinoma (HCC) patients compared with healthy controls in publications with an English abstract. A random-effect meta-analysis was performed using mean difference (MD) and 95% confidence intervals (CIs). Also, publication bias was evaluated through funnel plot analysis with the Begg's and Egger's tests.

Results

Out of 171 studies searched in the databases, nine studies were included in the meta-analysis. The pooled analysis with continuous data concluded that IL-10 level in the patients was significantly higher than the controls (MD = 6.96; 95% CI = 4.91-9.01; p < 0.00001), in the HCC patients was significantly higher than the cirrhotic patients (MD = 2.92; 95% CI = 0.72-5.12; p = 0.009), and was similar in the HCC patients compared with the patients with hepatitis (MD = 3.91; 95% CI = -4.25-12.07; p = 0.35).

Conclusion

The increased IL-10 levels in the HCC patients compared with the cirrhotic patients and the healthy controls may show a significant role of this cytokine in the elevated risk of HCC, but the lack of significant difference in the levels between HCC and hepatitis makes it an unreliable tumor marker in the latter.

IL-10 in the microenvironment of HNSCC inhibits the CpG ODN induced IFN-α secretion of pDCs

It has been shown that head and neck squamous cell carcinoma (HNSCC) are infiltrated by plasmacytoid dendritic cells (pDCs). The HNSCC TH2 biased microenvironment leads to strong alterations of the cellular functions of pDC and thus impairs the initiation and function of adequate immune responses. In this work we comprehensively analyzed the capacity of CpG-oligonucleotides to activate interferon (IFN)-α secretion of human pDC in the presence of HNSCC. IFN-α secretion was measured using the ELISA Technique. Class A CpG dinucleotide 2216 was used in different concentrations and time frames to stimulate the IFN-α production of human pDC from peripheral blood in the absence and presence of the HNSCC microenvironment. To elucidate single components that might induce the reduction of IFN-α secretion, pDC were exposed to different concentrations of HNSCC relevant cytokines such as IL-6, IL-8 and IL-10. In accordance to former experiments we found that HNSCC micro milieu severely depresses up to 75% of IFN-α secretion capacity of pDCs, if the stimulating Class A CpG 2216 is added to the culture. Preincubation of HNSCC supernatant leads to unrestorable reduction of IFN-α secretion in pDC and can not be restored by CpG 2216. Incubation of pDCs with single cytokines relevant for cancer progression within the HNSCC micro milieu show that IL-6 or IL-8 have no influence on the IFN-α secretion in pDCs, whereas IL-10 massively impairs the secretion in a dose dependent manner. This effect can be potentiated by synergistic incubation with IL-6 and can be abrogated by blocking antibodies to the IL-10 receptor. Interestingly, incubation with IL-10 is not the only factor that impairs the IFN-α secretion, as incubation with the whole HNSCC supernatant is even more effective in reducing the secretion, implying that additional factors play a role. We conclude that restoration of HNSCC induced TH2 bias could be improved by the inhibition of immune cell cytokine receptors in addition to immunostimulating approaches with CpG motifs.

Disease-Associated Plasmacytoid Dendritic Cells

Plasmacytoid dendritic cells (pDCs), also called natural interferon (IFN)-producing cells, represent a specialized cell type within the innate immune system. pDCs are specialized in sensing viral RNA and DNA by toll-like receptor-7 and -9 and have the ability to rapidly produce massive amounts of type 1 IFNs upon viral encounter. After producing type 1 IFNs, pDCs differentiate into professional antigen-presenting cells, which are capable of stimulating T cells of the adaptive immune system. Chronic activation of human pDCs by self-DNA or mitochondrial DNA contributes to the pathogenesis of systemic lupus erythematosis and IFN-related autoimmune diseases. Under steady-state conditions, pDCs play an important role in immune tolerance. In many types of human cancers, recruitment of pDCs to the tumor microenvironment contributes to the induction of immune tolerance. Here, we provide a systemic review of recent progress in studies on the role of pDCs in human diseases, including cancers and autoimmune/inflammatory diseases.

Soluble intercellular adhesion molecule-1 is associated with hepatocellular carcinoma risk: multiplex analysis of serum markers

Individualized assessment of hepatocellular carcinoma (HCC) risk in chronic liver disease remains challenging. Serum biomarkers including cytokines may offer helpful adjuncts to standard parameters for risk prediction. Our aim was to identify markers associated with increased HCC incidence. This was a prospective cohort study of 282 patients with both viral or non-viral chronic liver disease. Baseline serum cytokines and other markers were measured in multiplex with a commercially-available Luminex-based system. Patients were followed until death or HCC diagnosis. We performed Lasso-based survival analysis to determine parameters associated with HCC development. Cytokine mean florescence intensity (MFI) was the primary predictor and HCC development the primary outcome. 25 patients developed HCC with total follow-up of 1,363 person-years. Parameters associated with increased HCC incidence were cirrhosis, hepatic decompensation, and soluble serum intercellular adhesion molecule 1 (sICAM-1) MFI. No other molecules increased predictive power for HCC incidence. On univariate analysis, the parameters associated with HCC incidence in patients with cirrhosis were age, antiviral treatment, and high sICAM-1 MFI; on multivariate analysis, sICAM-1 remained associated with HCC development (adjusted HR = 2.75). On unbiased screening of serum cytokines and other markers in a diverse cohort, baseline sICAM-1 MFI is associated with HCC incidence.

Modulations in the Peripheral Immune System of Glioblastoma Patient Is Connected to Therapy and Tumor Progression-A Case Report from the IMMO-GLIO-01 Trial

Immune responses are important for efficient tumor elimination, also in immune privileged organs such as the brain. Fostering antitumor immunity has therefore become an important challenge in cancer therapy. This cannot only be achieved by immunotherapies as already standard treatments such as radiotherapy and chemotherapy modify the immune system. Consequently, the understanding of how the tumor, the tumor microenvironment, and immune system are modulated by cancer therapy is required for prognosis, prediction, and therapy adaption. The prospective, explorative, and observational IMMO-GLIO-01 trial was initiated to examine the detailed immune status and its modulation of about 50 patients suffering from primary glioblastoma multiforme (GBM) or anaplastic astrocytoma during standard therapy. Prior to the study, a flow cytometry-based assay was established allowing the analysis of 34 immune cell subsets and their activation state. Here, we present the case of the first and longest accompanied patient, a 53-year-old woman suffering from GBM in the front left lobe. In context of tumor progression and therapy, we describe the modulation of the peripheral immune status over 17 months. Distinct immune modulations that were connected to therapy response or tumor progression were identified. Inter alia, a shift of CD4:CD8 ratio was observed that correlated with tumor progression. Twice we observed a unique composition of peripheral immune cells that correlated with tumor progression. Thus, following up these immune modulations in a closely-meshed manner is of high prognostic and predictive relevance for supporting personalized therapy and increasing therapy success.

Clinical Trial registration: ClinicalTrials.gov, identifier NCT02022384 (registered retrospectively on 13th of December, 2013).

Tumor-derived factors affecting immune cells

Tumor progression is accompanied by the production of a wide array of immunosuppressive factors by tumor and non-tumor cells forming the tumor microenvironment. These factors belonging to cytokines, growth factors, metabolites, glycan-binding proteins and glycoproteins are responsible for the establishment of immunosuppressive networks leading towards tumor promotion, invasion and metastasis. In pre-clinical tumor models, the inactivation of some of these suppressive networks reprograms the phenotypic and functional features of tumor-infiltrating immune cells, ultimately favoring effective anti-tumor immune responses. We will discuss factors and mechanisms identified in both mouse and human tumors, and the possibility to associate drugs inhibiting these mechanisms with new immunotherapy strategies already entered in the clinical practice.

Epigenetic mechanisms of myeloid differentiation in the tumor microenvironment

Myeloid cells are extremely plastic as they respond and terminally differentiate into a plethora of functional types, in the blood or tissues, in response to a variety of growth factors, cytokines and pathogenic molecules. This plasticity is also manifested by the subversion of normal differentiation into the aberrant generation of a variety of tolerogenic myeloid cells in the tumoral microenvironment, where a variety of factors are released. Epigenetic mechanisms are in great part responsible for the plasticity of myeloid cells both under physiological and tumoral conditions. The development of compounds that inhibit epigenetic enzymes provides novel therapeutic opportunities to intercept the crosstalk between cancer cells and host myeloid cells. Here, we summarize our current knowledge on the myeloid cell types generated in the cancer environment, the factors and epigenetic enzymes participating in these processes and propose a number of potential targets for future pharmacological use.

Increased tumor-infiltrating plasmacytoid dendritic cells predicts poor prognosis in oral squamous cell carcinoma

OBJECTIVE

Accumulating evidence suggests that plasmacytoid dendritic cells (pDC) have a dual role not only in initiating anti-tumor immune responses but also in inducing immune tolerance to facilitate cancer development. The aim of this study was to investigate the distribution and function of tumor-infiltrating pDCs in primary oral squamous cell carcinoma (OSCC) and their relation to patient outcome.

METHODS

The distribution of pDCs in 10 normal oral mucosa and 60 OSCC tissues was detected by immunohistochemistry. The population of pDCs in six OSCC patients and six healthy donors was evaluated by flow cytometry. The relationship between tumor-infiltrating pDCs and clinicopathological data and patient outcome was analyzed accordingly. The capacity of pDCs to produce cytokines, such as IFN-α, IL-6, IL-8 and TNF-α in response to TLR-9 ligands (CpG-ODN) was measured by ELISA.

RESULT

PDCs were detected at high levels in 38.3% of the OSCC tissues, primarily in the stroma, but were absent in normal oral mucosa. The frequency of pDCs in OSCC tissue was significantly higher than that observed in normal oral mucosa. However, the distribution and population of circulating pDCs was similar between healthy donors and OSCC patients. Kaplan-Meier analysis revealed a significant association of increasing number of tumor-infiltrating pDCs with lymph node metastasis and overall survival. Multivariate analysis confirmed that high levels of tumor-infiltrating pDCs was an independent prognostic factor. Further cytokine analysis revealed a decreased secretion of IFN-α, IL-6 and TNF-α, which indicated an impaired function of tumor-infiltrating pDCs.

CONCLUSIONS

The increased number of tumor-infiltrating pDCs correlates with an adverse outcome in primary OSCC patients. This finding is not only suggestive of the contribution of pDCs in the progression of oral cancer but also presents an opportunity and a new target for OSCC immune therapy in oral cancer management.

Expression of CD14, IL10, and Tolerogenic Signature in Dendritic Cells Inversely Correlate with Clinical and Immunologic Response to TARP Vaccination in Prostate Cancer Patients

Purpose: Despite the vast number of clinical trials conducted so far, dendritic cell (DC)-based cancer vaccines have mostly shown unsatisfactory results. Factors and manufacturing procedures essential for these therapeutics to induce effective antitumor immune responses have yet to be fully characterized. We here aimed to identify DC markers correlating with clinical and immunologic response in a prostate carcinoma vaccination regimen.Experimental Design: We performed an extensive characterization of DCs used to vaccinate 18 patients with prostate carcinoma enrolled in a pilot trial of T-cell receptor gamma alternate reading frame protein (TARP) peptide vaccination (NCT00908258). Peptide-pulsed DC preparations (114) manufactured were analyzed by gene expression profiling, cell surface marker expression and cytokine release secretion, and correlated with clinical and immunologic responses.Results: DCs showing lower expression of tolerogenic gene signature induced strong antigen-specific immune response and slowing in PSA velocity, a surrogate for clinical response. These DCs were also characterized by lower surface expression of CD14, secretion of IL10 and MCP-1, and greater secretion of MDC. When combined, these four factors were able to remarkably discriminate DCs that were sufficiently potent to induce strong immunologic response.Conclusions: DC factors essential for the activation of immune responses associated with TARP vaccination in prostate cancer patients were identified. This study highlights the importance of in-depth characterization of DC vaccines and other cellular therapies, to understand the critical factors that hinder potency and potential efficacy in patients. Clin Cancer Res; 23(13); 3352-64. ©2017 AACR.

Interleukin 10 promotes immune response by increasing the survival of activated CD8+ T cells in human papillomavirus 16-infected cervical cancer

Human papillomavirus (HPV)-specific CD8+ T cells are present in HPV-infected cervical cancer patients and have demonstrated potent antitumor properties. However, these cells cannot control tumor progression in most patients. To investigate the underlying mechanisms involved in suppressing or promoting CD8+ T cell functions, we focused on interleukin 10 (IL-10), a pleiotropic cytokine with controversial roles in antitumor immunity. We found that compared to healthy controls, circulating CD8+ T cells in HPV 16-infected cervical cancer patients expressed significantly higher levels of IL-10. Interestingly, these CD8+ T cells from cervical cancer patients, but not those from healthy controls, responded to HPV 16 E6/E7 peptide stimulation by increasing IL-10 expression, demonstrating an antigen-specific IL-10 release. Addition of exogenous IL-10 improved the survival, but did not increase the proliferation, of peptide-stimulated CD8+ T cells. CD8+ T cells cultured in the presence of IL-10 also resulted in significantly higher interferon gamma (IFN-gamma) and granzyme B concentration, primarily due to improved cell survival. In resected cervical tumors, the frequency of tumor-infiltrating IL-10+ CD8+ T cells was positively correlated with the frequency of tumor-infiltrating IFN-gamma+ and granzyme B+ CD8+ T cells. Tumor-associated macrophages were more potent than peripheral blood monocyte-derived macrophages at inducing IL-10 expression in CD8+ T cells, possibly explaining the elevated IL-10+ CD8+ T cell frequency in cervical cancer patients. Together, these results are consistent with an immunostimulatory role of IL-10, which promoted CD8+ T cell response by increasing the survival of activated CD8+ T cells.

Tumor-derived factors modulating dendritic cell function

Dendritic cells (DC) play unique and diverse roles in the tumor occurrence, development, progression and response to therapy. First of all, DC can actively uptake tumor-associated antigens, process them and present antigenic peptides to T cells inducing and maintaining tumor-specific T cell responses. DC interaction with different immune effector cells may also support innate antitumor immunity, as well as humoral responses also known to inhibit tumor development in certain cases. On the other hand, DC are recruited to the tumor site by specific tumor-derived and stroma-derived factors, which may also impair DC maturation, differentiation and function, thus resulting in the deficient formation of antitumor immune response or development of DC-mediated tolerance and immune suppression. Identification of DC-stimulating and DC-suppressing/polarizing factors in the tumor environment and the mechanism of DC modulation are important for designing effective DC-based vaccines and for recovery of immunodeficient resident DC responsible for maintenance of clinically relevant antitumor immunity in patients with cancer. DC-targeting tumor-derived factors and their effects on resident and administered DC in the tumor milieu are described and discussed in this review.

Immune Response After Radiofrequency Ablation and Surgical Resection in Nonsmall Cell Lung Cancer

The objective includes radiofrequency ablation (RFA) of a cancerous nodule results in immunogenic cell death. Tumor antigens are presented and the inflammatory environment may help stimulate adaptive and innate antitumor immunity. The objective of this study was to investigate the immune response following RFA and subsequent surgical resection in early stage non-small cell lung cancer (NSCLC). In methods, a single-session approach of computed tomography-guided tumor biopsy with immediate frozen section (and proof of NSCLC) was performed followed by RFA of the tumor in 4 patients with a solitary pulmonary nodule. Blood samples were collected before RFA and 3 days thereafter. All patients underwent radical surgical resection by video-assisted thoracoscopic lobectomy 8 days following RFA. In results, intense infiltrations of CD4⁺ and CD8⁺ lymphocytes were found along the perimeter of the RFA-treated tumor tissue, whereas the central tumor areas remained devoid of lymphocytes. In the peripheral blood, the frequency of proinflammatory, immunostimulatory IFNγ-secreting, and immunostimulatory BDCA-3⁺/B7-H3^- dendritic cells increased after RFA. Furthermore, a significant increase in T-cell proliferation was detected in T-cell assays after RFA and tumor resection. In this article, a local and systemic immune response subsequent to RFA and complete surgical resection in patients with NSCLC was identified for the first time. Treatment of patients with NSCLC with RFA and surgery leads to an activated and highly T-cell-stimulatory phenotype of dendritic cells, which may promote long-term immunity against NSCLC. The data suggest that the RFA-induced necrotic tumor debris can serve as an in situ antigen source to induce an autologous antitumor immune response.