Semi mature blood dendritic cells exist in patients with ductal pancreatic adenocarcinoma owing to inflammatory factors released from the tumor

OMIP-095: 40-Color spectral flow cytometry delineates all major leukocyte populations in murine lymphoid tissues

High-dimensional immunoprofiling is essential for studying host response to immunotherapy, infection, and disease in murine model systems. However, the difficulty of multiparameter panel design combined with a lack of existing murine tools has prevented the comprehensive study of all major leukocyte phenotypes in a single assay. Herein, we present a 40-color flow cytometry panel for deep immunophenotyping of murine lymphoid tissues, including the spleen, blood, Peyer's patches, inguinal lymph nodes, bone marrow, and thymus. This panel uses a robust set of surface markers capable of differentiating leukocyte subsets without the use of intracellular staining, thus allowing for the use of cells in downstream functional experiments or multiomic analyses. Our panel classifies T cells, B cells, natural killer cells, innate lymphoid cells, monocytes, macrophages, dendritic cells, basophils, neutrophils, eosinophils, progenitors, and their functional subsets by using a series of co-stimulatory, checkpoint, activation, migration, and maturation markers. This tool has a multitude of systems immunology applications ranging from serial monitoring of circulating blood signatures to complex endpoint analysis, especially in pre-clinical settings where treatments can modulate leukocyte abundance and/or function. Ultimately, this 40-color panel resolves a diverse array of immune cells on the axes of time, tissue, and treatment, filling the niche for a modern tool dedicated to murine immunophenotyping.

Antibody drug conjugates: hitting the mark in pancreatic cancer?

Pancreatic cancer is one of the most common causes of cancer-related death, and the 5-year survival rate has only improved marginally over the last decade. Late detection of the disease means that in most cases the disease has advanced locally and/or metastasized, and curative surgery is not possible. Chemotherapy is still the first-line treatment however, this has only had a modest impact in improving survival, with associated toxicities. Therefore, there is an urgent need for targeted approaches to better treat pancreatic cancer, while minimizing treatment-induced side-effects. Antibody drug conjugates (ADCs) are one treatment option that could fill this gap. Here, a monoclonal antibody is used to deliver extremely potent drugs directly to the tumor site to improve on-target killing while reducing off-target toxicity. In this paper, we review the current literature for ADC targets that have been examined in vivo for treating pancreatic cancer, summarize current and on-going clinical trials using ADCs to treat pancreatic cancer and discuss potential strategies to improve their therapeutic window.

The diagnostic significance of the ZNF gene family in pancreatic cancer: a bioinformatics and experimental study

Background: Pancreatic adenocarcinoma (PAAD) is among the most devastating of all cancers with a poor survival rate. Therefore, we established a zinc finger (ZNF) protein-based prognostic prediction model for PAAD patients. Methods: The RNA-seq data for PAAD were downloaded from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases. Differentially expressed ZNF protein genes (DE-ZNFs) in PAAD and normal control tissues were screened using the "lemma" package in R. An optimal risk model and an independent prognostic value were established by univariate and multivariate Cox regression analyses. Survival analyses were performed to assess the prognostic ability of the model. Results: We constructed a ZNF family genes-related risk score model that is based on the 10 DE-ZNFs (ZNF185, PRKCI, RTP4, SERTAD2, DEF8, ZMAT1, SP110, U2AF1L4, CXXC1, and RMND5B). The risk score was found to be a significant independent prognostic factor for PAAD patients. Seven significantly differentially expressed immune cells were identified between the high- and low-risk patients. Then, based on the prognostic genes, we constructed a ceRNA regulatory network that includes 5 prognostic genes, 7 miRNAs and 35 lncRNAs. Expression analysis showed ZNF185, PRKCI and RTP4 were significantly upregulated, while ZMAT1 and CXXC1 were significantly downregulated in the PAAD samples in all TCGA - PAAD, GSE28735 and GSE15471 datasets. Moreover, the upregulation of RTP4, SERTAD2, and SP110 were verified by the cell experiments. Conclusion: We established and validated a novel, Zinc finger protein family - related prognostic risk model for patients with PAAD, that has the potential to inform patient management.

Advances in Human Dendritic Cell-Based Immunotherapy Against Gastrointestinal Cancer

Dendritic cells (DCs), the strongest antigen-presenting cells, are a focus for orchestrating the immune system in the fight against cancer. Basic scientific investigations elucidating the cellular biology of the DCs have resulted in new strategies in this fight, including cancer vaccinology, combination therapy, and adoptive cellular therapy. Although immunotherapy is currently becoming an unprecedented bench-to-bedside success, the overall response rate to the current immunotherapy in patients with gastrointestinal (GI) cancers is pretty low. Here, we have carried out a literature search of the studies of DCs in the treatment of GI cancer patients. We provide the advances in DC-based immunotherapy and highlight the clinical trials that indicate the therapeutic efficacies and toxicities related with each vaccine. Moreover, we also offer the yet-to-be-addressed questions about DC-based immunotherapy. This study focuses predominantly on the data derived from human studies to help understand the involvement of DCs in patients with GI cancers.

Tumor RNA transfected DCs derived from iPS cells elicit cytotoxicity against cancer cells induced from colorectal cancer patients in vitro

Significant efficacy of induced pluripotent stem cells (iPSCs) in generating DCs for cancer vaccine therapy was suggested in our previous studies. In clinical application of DC vaccine therapy, however, few DC vaccine systems have shown strong clinical response. To enhance immunogenicity in the DC vaccine, we transfected patient-derived iPSDCs with in vitro transcriptional RNA (ivtRNA), which was obtained from tumors of three patients with colorectal cancer. We investigated iPSDCs-ivtRNA which were induced by transfecting ivtRNA obtained from tumors of three colorectal cancer patients, and examined its antitumor effect. Moreover, we analyzed neoantigens expressed in colorectal cancer cells and examined whether iPSDCs-ivtRNA induced cytotoxic T lymphocytes (CTLs) against the predicted neoantigens. CTLs activated by iPSDCs-ivtRNA exhibited cytotoxic activity against the tumor spheroids in all three patients with colorectal cancer. Whole-exome sequencing revealed 1251 nonsynonymous mutations and 2155 neoantigens (IC₅₀ < 500 nM) were predicted. For IFN-γ ELISPOT assay, these candidate neoantigens were further prioritised and 12 candidates were synthesized. IFN-γ ELISPOT assay revealed that the CTLs induced by iPSDCs-ivtRNA responded to one of the candidate neoantigens. In vitro CTLs obtained by transfecting tumor-derived RNA into iPSDCs derived from three patients with colorectal cancer showed potent tumor-specific killing effect.

CD40L-armed oncolytic herpes simplex virus suppresses pancreatic ductal adenocarcinoma by facilitating the tumor microenvironment favorable to cytotoxic T cell response in the syngeneic mouse model

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant cancers worldwide. Despite the promising outcome of immune checkpoint inhibitors and agonist antibody therapies in different malignancies, PDAC exhibits high resistance due to its immunosuppressive tumor microenvironment (TME). Ameliorating the TME is thus a rational strategy for PDAC therapy. The intratumoral application of oncolytic herpes simplex virus-1 (oHSV) upregulates pro-inflammatory macrophages and lymphocytes in TME, and enhances the responsiveness of PDAC to immunotherapy. However, the antitumor activity of oHSV remains to be maximized. The aim of this study is to investigate the effect of the CD40L armed oHSV on the tumor immune microenvironment, and ultimately prolong the survival of the PDAC mouse model.

Methods

The membrane-bound form of murine CD40L was engineered into oHSV by CRISPR/Cas9-based gene editing. oHSV-CD40L induced cytopathic effect and immunogenic cell death were determined by microscopy and flow cytometry. The expression and function of oHSV-CD40L was assessed by reporter cell assay. The oHSV-CD40L was administrated intratumorally to the immune competent syngeneic PDAC mouse model, and the leukocytes in TME and tumor-draining lymph node were analyzed by multicolor flow cytometry. Intratumoral cytokines were determined by ELISA.

Results

Intratumoral application of oHSV-CD40L efficiently restrained the tumor growth and prolonged the survival of the PDAC mouse model. In TME, oHSV-CD40L-treated tumor accommodated more maturated dendritic cells (DCs), which in turn activated T helper 1 and cytotoxic CD8⁺ T cells in an interferon-γ-dependent and interleukin-12-dependent manner. In contrast, the regulatory T cells were significantly reduced in TME by oHSV-CD40L treatment. Repeated dosing and combinational therapy extended the lifespan of PDAC mice.

Conclusion

CD40L-armed oncolytic therapy endues TME with increased DCs maturation and DC-dependent activation of cytotoxic T cells, and significantly prolongs the survival of the model mice. This study may lead to the understanding and development of oHSV-CD40L as a therapy for PDAC in synergy with immune checkpoint blockade.

Tumour-Derived Reg3A Educates Dendritic Cells to Promote Pancreatic Cancer Progression

As a pancreatic inflammatory marker, regenerating islet-derived protein 3A (Reg3A) plays a key role in inflammation-associated pancreatic carcinogenesis by promoting cell proliferation, inhibiting apoptosis, and regulating cancer cell migration and invasion. This study aimed to reveal a novel immuno-regulatory mechanism by which Reg3A modulates tumour-promoting responses during pancreatic cancer (PC) progression. In an in vitro Transwell system that allowed the direct co-culture of human peripheral blood-derived dendritic cells (DCs) and Reg3A-overexpressing/ silenced human PC cells, PC cell-derived Reg3A was found to downregulate CD80, CD83 and CD86 expression on educated DCs, increase DC endocytic function, inhibit DC-induced T lymphocyte proliferation, reduce IL-12p70 production, and enhance IL-23 production by DCs. The positive effect of tumour-derived Reg3A-educated human DCs on PC progression was demonstrated in vivo by intraperitoneally transferring them into PC-implanted severe combined immunodeficiency (SCID) mice reconstituted with human T cells. A Reg3A-JAK2/STAT3 positive feedback loop was identified in DCs educated with Reg3A. In conclusion, as a tumour-derived factor, Reg3A acted to block the differentiation and maturation of the most important antigen-presenting cells, DCs, causing them to limit their potential anti-tumour responses, thus facilitating PC escape and progression.

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.

Systemic immunity in cancer

Immunotherapy has revolutionized cancer treatment, but efficacy remains limited in most clinical settings. Cancer is a systemic disease that induces many functional and compositional changes to the immune system as a whole. Immunity is regulated by interactions of diverse cell lineages across tissues. Therefore, an improved understanding of tumour immunology must assess the systemic immune landscape beyond the tumour microenvironment (TME). Importantly, the peripheral immune system is required to drive effective natural and therapeutically induced antitumour immune responses. In fact, emerging evidence suggests that immunotherapy drives new immune responses rather than the reinvigoration of pre-existing immune responses. However, new immune responses in individuals burdened with tumours are compromised even beyond the TME. Herein, we aim to comprehensively outline the current knowledge of systemic immunity in cancer.

Type 1 conventional dendritic cells are systemically dysregulated early in pancreatic carcinogenesis

Type 1 conventional dendritic cells (cDC1s) are typically thought to be dysregulated secondarily to invasive cancer. Here, we report that cDC1 dysfunction instead develops in the earliest stages of preinvasive pancreatic intraepithelial neoplasia (PanIN) in the Kras^LSL-G12D/+ Trp53^LSL-R172H/+ Pdx1-Cre–driven (KPC) mouse model of pancreatic cancer. cDC1 dysfunction is systemic and progressive, driven by increased apoptosis, and results in suboptimal up-regulation of T cell–polarizing cytokines during cDC1 maturation. The underlying mechanism is linked to elevated IL-6 concomitant with neoplasia. Neutralization of IL-6 in vivo ameliorates cDC1 apoptosis, rescuing cDC1 abundance in tumor-bearing mice. CD8⁺ T cell response to vaccination is impaired as a result of cDC1 dysregulation. Yet, combination therapy with CD40 agonist and Flt3 ligand restores cDC1 abundance to normal levels, decreases cDC1 apoptosis, and repairs cDC1 maturation to drive superior control of tumor outgrowth. Our study therefore reveals the unexpectedly early and systemic onset of cDC1 dysregulation during pancreatic carcinogenesis and suggests therapeutically tractable strategies toward cDC1 repair.

Type I interferons in pancreatic cancer and development of new therapeutic approaches

Immunotherapy has emerged as a new treatment strategy for cancer. However, its promise in pancreatic cancer has not yet been realized. Understanding the immunosuppressive tumor microenvironment of pancreatic cancer, and identifying new therapeutic targets to increase tumor-specific immune responses, is necessary in order to improve clinical outcomes. Type I interferons, e.g. IFN-α and -β, are considered as an important bridge between the innate and adaptive immune system. Thereby, type I IFNs induce a broad spectrum of anti-tumor effects, including immunologic, vascular, as well as direct anti-tumor effects. While IFN therapies have been around for a while, new insights into exogenous and endogenous activation of the IFN pathway have resulted in new IFN-related cancer treatment strategies. Here, we focus on the pre-clinical and clinical evidence of novel ways to take advantage of the type I IFN pathway, such as IFN based conjugates and activation of the STING and RIG-I pathways.

Topographical Distribution and Spatial Interactions of Innate and Semi-Innate Immune Cells in Pancreatic and Other Periampullary Adenocarcinoma

Background

The clinical management of pancreatic and other periampullary neoplasms remains challenging. In contrast to other cancer types, immunotherapies are largely ineffective, and the reason for the deprived immune response and the immune inhibiting cellular composition is only fragmentarily understood. The aim of this study was to comprehensively map the abundance, topographic distribution and spatial interaction of innate and innate-like immune cells in the tumor microenvironment of periampullary adenocarcinoma.

Methods

Multiplexed immunofluorescent imaging was performed on tissue microarrays with tumors from a consecutive cohort of 175 patients with resected periampullary adenocarcinoma. To obtain a detailed spatial analysis of immune cell infiltration, two multiplex immune panels including antibodies against CD3, NKp46, CD56, CD68, CD163 and CD1a, CD208, CD123, CD15, CD68 and pan-cytokeratin were applied.

Results

The infiltration of natural killer (NK) and NK-like T (NKT) cells was lower in malignant compared to benign tissue. NKT cells were more abundant in intestinal type compared to pancreatobiliary type tumors, and were associated with more favorable clinicopathological features and a prolonged survival. The interaction of NKp46⁺ NKT cells with macrophages was also associated with a prolonged survival.

Conclusions

This study provides a comprehensive map of the innate immune landscape in periampullary adenocarcinoma. NK cells, and even more so NKT cells, are revealed to be central players in the local immune response in a clinically relevant context.

Local and systemic immunosuppression in pancreatic cancer: Targeting the stalwarts in tumor's arsenal

Late detection, compromised immune system, and chemotherapy resistance underlie the poor patient prognosis for pancreatic ductal adenocarcinoma (PDAC) patients, making it the 3^rd leading cause of cancer-related deaths in the United States. Cooperation between the tumor cells and the immune system leads to the immune escape and eventual establishment of the tumor. For more than 20 years, sincere efforts have been made to intercept the tumor-immune crosstalk and identify the probable therapeutic targets for breaking self-tolerance toward tumor antigens. However, the success of these studies depends on detailed examination and understanding of tumor-immune cell interactions, not only in the primary tumor but also at distant systemic niches. Innate and adaptive arms of the immune system sculpt tumor immunogenicity, where they not only aid in providing an amenable environment for their survival but also act as a driver for tumor relapse at primary or distant organ sites. This review article highlights the key events associated with tumor-immune communication and associated immunosuppression at both local and systemic microenvironments in PDAC. Furthermore, we discuss the approaches and benefits of targeting both local and systemic immunosuppression for PDAC patients. The present articles integrate data from clinical and genetic mouse model studies to provide a widespread consensus on the role of local and systemic immunosuppression in undermining the anti-tumor immune responses against PDAC.

An Immunological Glance on Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has still a dismal prognosis. Different factors such as mutational landscape, intra- and intertumoral heterogeneity, stroma, and immune cells impact carcinogenesis of PDAC associated with an immunosuppressive microenvironment. Different cell types with partly opposing roles contribute to this milieu. In recent years, immunotherapeutic approaches, including checkpoint inhibitors, were favored to treat cancers, albeit not every cancer entity exhibited benefits in a similar way. Indeed, immunotherapies rendered little success in pancreatic cancer. In this review, we describe the communication between the immune system and pancreatic cancer cells and propose some rationale why immunotherapies may fail in the context of pancreatic cancer. Moreover, we delineate putative strategies to sensitize PDAC towards immunological therapeutics and highlight the potential of targeting neoantigens.

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.

The Multiple Layers of the Tumor Environment

The notion of tumor microenvironment (TME) has been brought to the forefront of recent scientific literature on cancer. However, there is no consensus on how to define and spatially delineate the TME. We propose that the time is ripe to go beyond an all-encompassing list of the components of the TME, and to construct a multilayered view of cancer. We distinguish six layers of environmental interactions with the tumor and show that they are associated with distinct mechanisms, and ultimately with distinct therapeutic approaches.

Pancreatic-cancer-cell-derived trefoil factor 2 impairs maturation and migration of human monocyte-derived dendritic cells in vitro

Pancreatic cancer is a challenging disease with a high mortality rate. While the importance of crosstalk between cancer and immune cells has been well documented, the understanding of this complex molecular network is incomplete. Thus, identification of the secreted proteins contributing to the immunosuppressive microenvironment in pancreatic cancer is crucial for effective diagnosis and/or therapy. We utilized a public microarray dataset (GSE16515) from the Gene Expression Omnibus database to identify genes for secreted proteins in pancreatic cancer. RT-PCR and ELISA of the pancreatic cancer cell lines validated the cellular origin of the selected genes. For functional assay of the selected proteins, we utilized human-monocyte-derived dendritic cells (DCs). From the list of the secreted proteins, trefoil factor 2 (TFF2) was further examined as a potential chemokine/cytokine. While TFF2 did not significantly affect the phenotypic maturation and the allostimulatory capacity of DCs, TFF2 preferentially attracted immature (but not mature) DCs and inhibited their endocytic activity. Our data suggest that TFF2 from pancreatic cancer cells may attract immature DCs and affect the initial stage of DC maturation, thereby contributing to the induction of immune tolerance against pancreatic cancer.

Immunotherapy for pancreatic cancer: A long and hopeful journey

Multiple therapeutic strategies have been developed to treat pancreatic cancer. However, the outcomes of these approaches are disappointing. Due to deeper understandings of the pivotal roles of the immune system in pancreatic cancer tumorigenesis and progression, novel therapeutic strategies based on immune cells and the tumor microenvironment are being investigated. Some of these approaches, such as checkpoint inhibitors, chimeric antigen receptor T-cell therapy, and BiTE antibodies, have achieved exciting outcomes in preclinical and clinical trials. The current review describes the roles of immune cells and the immunosuppressive microenvironment in the development of pancreatic cancer, as well as the preclinical and clinical outcomes and benefits of recent immunotherapeutic approaches, which may help us further disclose the mechanisms of pancreatic cancer progression and the dialectical views of feasibility and effectiveness of immunotherapy in treatment of pancreatic cancer.

Targeting dendritic cells in pancreatic ductal adenocarcinoma

Dendritic cells (DC) are an integral part of the tumor microenvironment. Pancreatic cancer is characterized by reduced number and function of DCs, which impacts antigen presentation and contributes to immune tolerance. Recent data suggest that exosomes can mediate communication between pancreatic cancer cells and DCs. Furthermore, levels of DCs may serve as prognostic factors. There is also growing evidence for the effectiveness of vaccination with DCs pulsed with tumor antigens to initiate adaptive cytolytic immune responses via T cells. Most experience with DC-based vaccination has been gathered for MUC1 and WT1 antigens, where clinical studies in advanced pancreatic cancer have provided encouraging results. In this review, we highlight the role of DC in the course, prognosis and treatment of pancreatic cancer.

Cancer Vaccine Therapy Using Carcinoembryonic Antigen - expressing Dendritic Cells generated from Induced Pluripotent Stem Cells

Clinical application of dendritic cell (DC) vaccine therapy is hindered by the need for a large quantity of DCs generated from peripheral blood monocytes of the patient. We investigated whether genetically modified human induced pluripotent stem cell (iPSC)-derived dendritic cells (hiPSDCs) expressing carcinoembryonic antigen (CEA) could induce CEA-specific cytotoxic T cells in a human model and whether genetically modified mouse iPSDCs (miPSDCs) expressing CEA showed an actual antitumor effect using a CEA transgenic mouse model. We differentiated hiPSDCs from iPSCs of three healthy donors and transduced CEA cDNA into the hiPSDCs. The surface marker expression, cytokine secretion and migratory capacity of the hiPSDCs were equivalent to those of human monocyte-derived DCs (hMoDCs). Cytotoxic T cells activated by hiPSDCs-CEA exhibited CEA-specific cytotoxic activity against the target cells expressing CEA. Furthermore, in the CEA transgenic mouse model, cytotoxic T cells activated in mice immunized with miPSDCs-CEA displayed CEA-specific cytotoxic activity against MC38-CEA. In the subcutaneous tumour model, vaccination with miPSDCs-CEA achieved a significant growth inhibitory effect on MC38-CEA. No adverse events caused by the administration of miPSDCs were observed. Genetic modification of iPSDCs, inducing the expression of CEA, is a promising tool for clinical applications of vaccine therapy for treating gastrointestinal cancer patients.

Challenges and Perspectives for Immunotherapy in Adenocarcinoma of the Pancreas: The Cancer Immunity Cycle

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with a devastating 5-year overall survival of only approximately 7%. Although just 4% of all malignant diseases are accounted to PDAC, it will become the second leading cause of cancer-related deaths before 2030. Immunotherapy has proven to be a promising therapeutic option in various malignancies such as melanoma, non-small cell lung cancer (NSCLC), microsatellite instability-high gastrointestinal cancer, urinary tract cancer, kidney cancer, and others. In this review, we summarize recent findings about immunological aspects of PDAC with the focus on the proposed model of the "cancer immunity cycle". By this model, a deeper understanding of the underlying mechanism in achieving a T-cell response against cancer cells is provided. There is currently great interest in the field around designing novel immunotherapy combination studies for PDAC based on a sound understanding of the underlying immunobiology.

Tumor microenvironment and noncoding RNAs as co-drivers of epithelial-mesenchymal transition and cancer metastasis

Reciprocal interactions between cancer cells and tumor microenvironment (TME) are crucial events in tumor progression and metastasis. Pervasive stromal reprogramming of TME modifies numerous cellular functions, including extracellular matrix (ECM) stiffness, inflammation, and immunity. These environmental factors allow selection of more aggressive cells that develop adaptive strategies associating plasticity and epithelial-mesenchymal transition (EMT), stem-like phenotype, invasion, immunosuppression, and resistance to therapies. EMT is a morphomolecular process that endows epithelial tumor cells with mesenchymal properties, including reduced adhesion and increased motility. Numerous studies have demonstrated involvement of noncoding RNAs (ncRNAs), such as miRNAs and lncRNAs, in tumor initiation, progression, and metastasis. NcRNAs regulate every hallmark of cancer and have now emerged as new players in induction and regulation of EMT. The reciprocal regulatory interactions between ncRNAs, TME components, and cancer cells increase the complexity of gene expression and protein translation in cancer. Thus, deeper understanding of molecular mechanisms controlling EMT will not only shed light on metastatic processes of cancer cells, but enhance development of new therapies targeting metastasis. In this review, we will provide recent findings on the role of known ncRNAs relevant to EMT and cancer metastasis and discuss the role of the interaction between ncRNAs and TME as co-drivers of EMT. Developmental Dynamics 247:405-431, 2018. © 2017 Wiley Periodicals, Inc.

The clinical importance of tumour-infiltrating macrophages and dendritic cells in periampullary adenocarcinoma differs by morphological subtype

Background

Dendritic cells (DC) and tumour-associated macrophages (TAM) are essential in linking the innate and adaptive immune response against tumour cells and tumour progression. These cells are also potential target for immunotherapy as well as providing a handle to investigate immune status in the tumour microenvironment. The aim of the present study was to examine their impact on prognosis and chemotherapy response in periampullary adenocarcinoma, including pancreatic cancer, with particular reference to morphological subtype.

Methods

The density of tolerogenic immature CD1a⁺ dendritic cells (DC), and MARCO⁺, CD68⁺ and CD163⁺ tissue-associated macrophages (TAM) was analysed by immunohistochemistry in tissue micro arrays with tumours from 175 consecutive cases of periampullary adenocarcinoma who had undergone pancreaticoduodenectomy, 110 with pancreatobiliary type (PB-type) and 65 with intestinal type (I-type) morphology. Kaplan–Meier and Cox regression analyses were applied to determine the impact of immune cell infiltration on 5-year overall survival (OS).

Results

High density of CD1a⁺ DCs was an independent prognostic factor for a reduced OS in PB-type but not in I-type tumours (adjusted HR = 2.35; 95% CI 1.13–4.87). High density of CD68⁺ and CD163⁺ TAM was significantly associated with poor OS in the whole cohort, however only in unadjusted analysis (HR = 1.67; 95% CI 1.06–2.63, and HR = 1.84; 95% CI 1.09–3.09, respectively) and not in strata according to morphological subtype. High density of MARCO⁺ macrophages was significantly associated with poor prognosis in I-type but not in PB-type tumours (HR = 2.14 95% CI 1.03–4.44), and this association was only evident in patients treated with adjuvant chemotherapy. The prognostic value of the other investigated immune cells did not differ significantly in strata according to adjuvant chemotherapy.

Conclusions

The results from this study demonstrate that high infiltration of tolerogenic immature DCs independently predicts a shorter survival in patients with PB-type periampullary adenocarcinoma, and that high density of the MARCO⁺ subtype of TAMs predicts a shorter survival in patients with I-type tumours. These results emphasise the importance of taking morphological subtype into account in biomarker studies related to periampullary cancer, and indicate that therapies targeting dendritic cells may be of value in the treatment of PB-type tumours, which are associated with the worst prognosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1256-y) contains supplementary material, which is available to authorized users.

Tumor cell expression of immune inhibitory molecules and tumor-infiltrating lymphocyte count predict cancer-specific survival in pancreatic and ampullary cancer

Understanding the mechanisms of immune resistance in pancreatic and ampullary cancers is crucial for the development of suitable biomarkers and effective immunotherapeutics. Our aim was to examine the expression of the immune inhibiting molecules PD-L1, Galectin-9, HVEM, IDO and HLA-G, as well as CD8+ and FoxP3+ tumor infiltrating lymphocytes (TIL), in pancreatic and ampullary cancers, and to relate their individual, as well as their combined expression, to cancer survival. Tumor tissue from 224 patients with resected pancreatic (n = 148) and ampullary (n = 76) cancer was used to construct tissue-microarrays. Expression of immune inhibitory molecules and TIL was examined by immunohistochemistry. We show that immune inhibitory molecules are prevalently expressed. Moreover, high tumor expression of PD-L1 (p = 0.002), Gal-9 (p = 0.003), HVEM (p = 0.001), IDO (p = 0.049), HLA-G (p = 0.004) and high CD8/FoxP3 TIL ratio (p = 0.006) were associated with improved cancer-specific survival. All immune biomarkers, with the exception of IDO, were individually predictive of cancer-specific survival when adjusted for clinicopathologic characteristics. For every additional immune biomarker present survival was almost two-fold prolonged (HR 0.57 95%CI 0.47-0.69, p < 0.0001). When patients with pancreatic and ampullary cancer were analyzed separately the results were similar. We conclude that pancreas and ampullary cancers are rich in expression of immune-inhibitory molecules. These molecules can be targets for future immunotherapeutics, as well as form powerful immunological biomarkers. We propose that such immune biomarker panels be included in future prospective immunotherapy trials.

Oncolytic viral therapy for pancreatic cancer

Outcomes of pancreatic adenocarcinoma (PDA) remain dismal despite extensive clinical investigation. Combination chemotherapy provides modest improvements in survival above best supportive care, and immunotherapy has thus far not proven effective. Nevertheless, growing insight into antitumor immunity and the tumor microenvironment has inspired the discovery of novel agents targeting PDA. Oncolytic viruses represent an emerging class of immunotherapeutic agents that have undergone extensive preclinical investigation and warrant further investigation in well-designed clinical trials.

Role of immune cells in pancreatic cancer from bench to clinical application: An updated review

BACKGROUND

Pancreatic cancer (PC) remains difficult to treat, despite the recent advances in various anticancer therapies. Immuno-inflammatory response is considered to be a major risk factor for the development of PC in addition to a combination of genetic background and environmental factors. Although patients with PC exhibit evidence of systemic immune dysfunction, the PC microenvironment is replete with immune cells.

METHODS

We searched PubMed for all relevant English language articles published up to March 2016. They included clinical trials, experimental studies, observational studies, and reviews. Trials enrolled at Clinical trial.gov were also searched.

RESULTS

PC induces an immunosuppressive microenvironment, and intratumoral activation of immunity in PC is attenuated by inhibitory signals that limit immune effector function. Multiple types of immune responses can promote an immunosuppressive microenvironment; key regulators of the host tumor immune response are dendritic cells, natural killer cells, macrophages, myeloid derived suppressor cells, and T cells. The function of these immune cells in PC is also influenced by chemotherapeutic agents and the components in tumor microenvironment such as pancreatic stellate cells. Immunotherapy of PC employs monoclonal antibodies/effector cells generated in vitro or vaccination to stimulate antitumor response. Immune therapy in PC has failed to improve overall survival; however, combination therapies comprising immune checkpoint inhibitors and vaccines have been attempted to increase the response.

CONCLUSION

A number of studies have begun to elucidate the roles of immune cell subtypes and their capacity to function or dysfunction in the tumor microenvironment of PC. It will not be long before immune therapy for PC becomes a clinical reality.

Bacterial ghosts as adjuvants in syngeneic tumour cell lysate-based anticancer vaccination in a murine lung carcinoma model

Instead of relying on external anticancer factors for treatment, immunotherapy utilizes the host's own immune system and directs it against given tumour antigens. This study demonstrated that it is possible to overcome the documented immunosuppressive properties of tumour cell lysate by supplementing it with appropriate adjuvant. Lewis lung carcinoma (LLC)‑challenged C57BL/6 mice were treated with LLC cryo‑lysate mixed with either bacterial ghosts (BGs) generated from E. coli Nissle 1917 or B. subtilis 70 kDa protein as adjuvants. Median and overall survival, the size of metastatic foci in lung tissue and levels of circulating CD8a+ T cells were evaluated and compared to the untreated control mice or mice treated with LLC lysate alone. After primary tumour removal, a course of three subcutaneous vaccinations with LLC lysate supplemented with BGs led to a significant increase in overall survival (80% after 84 days of follow‑up vs. 40% in untreated control mice), a significant increase in circulating CD8a+ T cells (16.57 vs. 12.6% in untreated control mice) and a significant decrease in metastasis foci area and incidence. LLC lysate supplemented with B. subtilis protein also improved the inspected parameters in the treated mice, when compared against the untreated control mice, but not to a significant degree. Therefore, whole cell lysate supplemented with BGs emerges as an immunostimulatory construct with potential clinical applications in cancer treatment.

Clinical impact of chemotherapy to improve tumor microenvironment of pancreatic cancer

A perioperative multimodal strategy including combination chemotherapy and radiotherapy, in addition to surgical resection, has been acknowledged to improve patient prognosis. However chemotherapy has not been actively applied as an immunomodulating modality because of concerns about various immunosuppressive effects. It has recently been shown that certain chemotherapeutic agents could modify tumor microenvironment and host immune responses through several underlying mechanisms such as immunogenic cell death, local T-cell infiltration and also the eradication of immune-suppressing regulatory cells such as regulatory T cells (Tregs) and myeloid-derived suppressor cells. With the better understanding of the cell components in the tumor microenvironment and the effect of chemotherapy to improve tumor microenvironment, it has been gradually clear that the chemotherapeutic agents is two-edged sword to have both immune promoting and suppressing effects. The cellular components of the tumor microenvironment include infiltrating T lymphocytes, dendritic cells, regulatory T cells, tumor associated macrophages, myeloid derived suppressor cells and cancer associated fibroblasts. Based on the better understanding of tumor microenvironment following chemotherapy, the treatment protocol could be modified as personalized medicine and the prognosis of pancreas cancer would be more improved utilizing multimodal chemotherapy. Here we review the recent advances of chemotherapy to improve tumor microenvironment of pancreatic cancer, introducing the unique feature of tumor microenvironment of pancreatic cancer, interaction between anti-cancer reagents and these constituting cells and future prospects.

From bench to bedside a comprehensive review of pancreatic cancer immunotherapy

The incidence of pancreatic cancer has been increasing while its 5-year survival rate has not changed in decades. In the era of personalized medicine, immunotherapy has emerged as a promising treatment modality in a variety of malignancies, including pancreatic cancer. This review will discuss the unique pancreatic tumor microenvironment, including the cells and receptors that transform the pancreas from its normal architecture into a complex mix of suppressor immune cells and dense extracellular matrix that allows for the unrestricted growth of cancer cells. Next, we will highlight the recently completed immunotherapy clinical trials in pancreatic cancer. Finally, we will explore the on-going immunotherapy clinical trials and future directions of this engaging and changing field.

Pancreatic cancer: role of the immune system in cancer progression and vaccine-based immunotherapy

Pancreatic cancer (PC) is the 5th leading cause of cancer related death in the developed world with more than 260,000 deaths annually worldwide and with a dismal 5-year survival. Surgery is the only potential hope of cure for PC, but, unfortunately, only 20% PC patients is resectable at the time of diagnosis. Therapeutic research efforts have mainly focused on improvements in radio/ chemo treatments and to date, there are only a few chemotherapeutic agents that have shown to be effective against PC, including gemcitabine with or without abraxane as well as a combination of 5-FU, leucovorin, oxaliplatin and irinotecan (the so-called FOLFIRINOX regimen). The survival of patients treated with these regimens is marginal and hence we are in urgent need of novel therapeutic approaches to treat pancreatic cancer. The success of immunotherapeutic strategies in other cancers and various evidences that pancreatic adenocarcinoma elicits antitumor immune responses, suggest that immunotherapies can be a promising alternative treatment modality for this deadly disease. PC immunotherapy treatments include passive immunotherapeutic approaches, such as the use of effector cells generated in vitro, and active immunotherapeutic strategies, which goal is to stimulate an antitumor response in vivo, by means of vaccination. In this review, we describe the immune suppressive mechanisms of pancreatic cancer and discuss recent preclinical and clinical efforts toward PC immunotherapy, including passive approaches, such as the use of antibodies and active strategies (vaccination), with a special mention of most recent treatment with CRS-207 and GVAX.

An Optimization-Driven Analysis Pipeline to Uncover Biomarkers and Signaling Paths: Cervix Cancer

Establishing how a series of potentially important genes might relate to each other is relevant to understand the origin and evolution of illnesses, such as cancer. High-throughput biological experiments have played a critical role in providing information in this regard. A special challenge, however, is that of trying to conciliate information from separate microarray experiments to build a potential genetic signaling path. This work proposes a two-step analysis pipeline, based on optimization, to approach meta-analysis aiming to build a proxy for a genetic signaling path.

Artificial Antigen Presenting Cells: An Off the Shelf Approach for Generation of Desirable T-Cell Populations for Broad Application of Adoptive Immunotherapy

Adoptive transfer of antigen specific T-cells can lead to eradication of cancer and viral infections. The broad application of this approach has further been hampered by the limited availability of adequate numbers of T-cells for treatment in a timely manner. This has led to efforts for the development of efficient methods to generate large numbers of T-cells with specificity for tumor or viral antigens that can be harnessed for use in cancer therapy. Recent studies have demonstrated that during encounter with tumor antigen, the signals delivered to T-cells by professional antigen-presenting cells can affect T-cell programming and their subsequent therapeutic efficacy. This has stimulated efforts to develop artificial antigen-presenting cells that allow optimal control over the signals provided to T-cells. In this review, we will discuss the cellular artificial antigen-presenting cell systems and their use in T-cell adoptive immunotherapy for cancer and infections.

Pancreatic ductal adenocarcinoma: From genetics to biology to radiobiology to oncoimmunology and all the way back to the clinic

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death. Despite improvements in the clinical management, the prognosis of PDAC remains dismal. In the present comprehensive review, we will examine the knowledge of PDAC genetics and the new insights into human genome sequencing and clonal evolution. Additionally, the biology and the role of the stroma in tumour progression and response to treatment will be presented. Furthermore, we will describe the evidence on tumour chemoresistance and radioresistance and will provide an overview on the recent advances in PDAC metabolism and circulating tumour cells. Next, we will explore the characteristics and merits of the different mouse models of PDAC. The inflammatory milieu and the immunosuppressive microenvironment mediate tumour initiation and treatment failure. Hence, we will also review the inflammatory and immune escaping mechanisms and the new immunotherapies tested in PDAC. A better understanding of the different mechanisms of tumour formation and progression will help us to identify the best targets for testing in future clinical studies of PDAC.

Overcoming immunosuppression to enhance a p53MVA vaccine

A Phase I trial of a p53-targeting modified vaccinia Ankara (p53MVA) vaccine in patients afflicted with refractory gastrointestinal cancers demonstrated enhanced T-cell recognition of p53 following vaccination. However, this effect was transient suggesting that p53MVA requires combination with immunomodulatory agents to deliver clinical benefit. Here, we outline our rationale for combining p53MVA with immunomodulatory chemotherapy in a forthcoming trial.

Pivotal role of pervasive neoplastic and stromal cells reprogramming in circulating tumor cells dissemination and metastatic colonization

Reciprocal interactions between neoplastic cells and their microenvironment are crucial events in carcinogenesis and tumor progression. Pervasive stromal reprogramming and remodeling that transform a normal to a tumorigenic microenvironment modify numerous stromal cells functions, status redox, oxidative stress, pH, ECM stiffness and energy metabolism. These environmental factors allow selection of more aggressive cancer cells that develop important adaptive strategies. Subpopulations of cancer cells acquire new properties associating plasticity, stem-like phenotype, unfolded protein response, metabolic reprogramming and autophagy, production of exosomes, survival to anoikis, invasion, immunosuppression and therapeutic resistance. Moreover, by inducing vascular transdifferentiation of cancer cells and recruiting endothelial cells and pericytes, the tumorigenic microenvironment induces development of tumor-associated vessels that allow invasive cells to gain access to the tumor vessels and to intravasate. Circulating cancer cells can survive in the blood stream by interacting with the intravascular microenvironment, extravasate through the microvasculature and interact with the metastatic microenvironment of target organs. In this review, we will focus on many recent paradigms involved in the field of tumor progression.

Complex role for the immune system in initiation and progression of pancreatic cancer

The immune system plays a complex role in the development and progression of pancreatic cancer. Inflammation can promote the formation of premalignant lesions and accelerate pancreatic cancer development. Conversely, pancreatic cancer is characterized by an immunosuppressive environment, which is thought to promote tumor progression and invasion. Here we review the current literature describing the role of the immune response in the progressive development of pancreatic cancer, with a focus on the mechanisms that drive recruitment and activation of immune cells at the tumor site, and our current understanding of the function of the immune cell types at the tumor. Recent clinical and preclinical data are reviewed, detailing the involvement of the immune response in pancreatitis and pancreatic cancer, including the role of specific cytokines and implications for disease outcome. Acute pancreatitis is characterized by a predominantly innate immune response, while chronic pancreatitis elicits an immune response that involves both innate and adaptive immune cells, and often results in profound systemic immune-suppression. Pancreatic adenocarcinoma is characterized by marked immune dysfunction driven by immunosuppressive cell types, tumor-promoting immune cells, and defective or absent inflammatory cells. Recent studies reveal that immune cells interact with cancer stem cells and tumor stromal cells, and these interactions have an impact on development and progression of pancreatic ductal adenocarcinoma (PDAC). Finally, current PDAC therapies are reviewed and the potential for harnessing the actions of the immune response to assist in targeting pancreatic cancer using immunotherapy is discussed.

Challenges and future directions in therapeutics for pancreatic ductal adenocarcinoma

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death in the USA. The 5-year survival of < 5% has not changed in decades. In contrast to other major cancers, the incidence of PDAC is increasing.

AREAS COVERED

The aims of this paper are first to analyze why PDAC is so difficult to treat and, second, to suggest future directions for PDAC therapeutics. The authors provide an article that is based on a comprehensive search through MEDLINE and the clinicalTrials.gov website.

EXPERT OPINION

Progress has been made recently. Notably, FOLFIRINOX or nab-paclitaxel plus gemcitabine provide survival benefit over gemcitabine alone, which was previously the mainstay of therapy for PDAC. Most of the current trials are testing combinations of repurposed drugs rather than addressing key targets in the PDAC pathogenesis. It is clear that to really make an impact on this disease, it will be necessary to address three different problems with targeted therapeutics. First, it is important to eradicate PDAC stem cells that result in recurrence. Second, it is important to reduce the peritumoral stroma that provides the tumors with growth support and provides a barrier to access of therapeutic agents. Finally, it is important to address the marked cachexia and metabolic derangement that contribute to morbidity and mortality and further complicate therapeutic intervention.

p53MVA therapy in patients with refractory gastrointestinal malignancies elevates p53-specific CD8+ T-cell responses

PURPOSE

To conduct a phase I trial of a modified vaccinia Ankara (MVA) vaccine delivering wild-type human p53 (p53MVA) in patients with refractory gastrointestinal cancers.

EXPERIMENTAL DESIGN

Three patients were vaccinated with 1.0×10(8) plaque-forming unit (pfu) p53MVA followed by nine patients at 5.6×10(8) pfu. Toxicity was classified using the NCI Common Toxicity Criteria and clinical responses were assessed by CT scan. Peripheral blood samples were collected pre- and post-immunization for immunophenotyping, monitoring of p53MVA-induced immune response, and examination of PD1 checkpoint inhibition in vitro.

RESULTS

p53MVA immunization was well tolerated at both doses, with no adverse events above grade 2. CD4+ and CD8+ T cells showing enhanced recognition of a p53 overlapping peptide library were detectable after the first immunization, particularly in the CD8+ T-cell compartment (P=0.03). However, in most patients, this did not expand further with the second and third immunization. The frequency of PD1+ T cells detectable in patients' peripheral blood mononuclear cells (PBMC) was significantly higher than in healthy controls. Furthermore, the frequency of PD1+ CD8+ T cells showed an inverse correlation with the peak CD8+ p53 response (P=0.02) and antibody blockade of PD1 in vitro increased the p53 immune responses detected after the second or third immunizations. Induction of strong T-cell and antibody responses to the MVA backbone were also apparent.

CONCLUSION

p53MVA was well tolerated and induced robust CD8+ T-cell responses. Combination of p53MVA with immune checkpoint inhibition could help sustain immune responses and lead to enhanced clinical benefit.

Pancreatic ductal adenocarcinoma: a review of immunologic aspects

With the continued failures of both early diagnosis and treatment options for pancreatic cancer, it is now time to comprehensively evaluate the role of the immune system on the development and progression of pancreatic cancer. It is important to develop strategies that harness the molecules and cells of the immune system to treat this disease. This review will focus primarily on the role of immune cells in the development and progression of pancreatic ductal adenocarcinoma and to evaluate what is known about the interaction of immune cells with the tumor microenvironment and their role in tumor growth and metastasis. We will conclude with a brief discussion of therapy for pancreatic cancer and the potential role for immunotherapy. We hypothesize that the role of the immune system in tumor development and progression is tissue specific. Our hope is that better understanding of this process will lead to better treatments for this devastating disease.

Immune adjuvants as critical guides directing immunity triggered by therapeutic cancer vaccines

Tumor growth is controlled by natural antitumor immune responses alone or by augmented immune reactivity resulting from different forms of immunotherapy, which has demonstrated clinical benefit in numerous studies, although the overall percentage of patients with durable clinical responses remains limited. This is attributed to the heterogeneity of the disease, the inclusion of late-stage patients with no other treatment options and advanced tumor-associated immunosuppression, which may be consolidated by certain types of chemotherapy. Despite variable responsiveness to distinct types of immunotherapy, therapeutic cancer vaccination has shown meaningful efficacy for a variety of cancers. A key step during cancer vaccination involves the appropriate modeling of the functional state of dendritic cells (DCs) capable of co-delivering four critical signals for proper instruction of tumor antigen-specific T cells. However, the education of DCs, either directly in situ, or ex vivo by various complex procedures, lacks standardization. Also, it is questioned whether ex vivo-prepared DC vaccines are superior to in situ-administered adjuvant-guided vaccines, although both approaches have shown success. Evaluation of these variables is further complicated by a lack of consensus in evaluating vaccination clinical study end points. We discuss the role of signals needed for the preparation of classic in situ and modern ex vivo DC vaccines capable of proper reprogramming of antitumor immune responses in patients with cancer.

Role of the immune system in pancreatic cancer progression and immune modulating treatment strategies

Traditional chemotherapeutics have largely failed to date to produce significant improvements in pancreatic cancer survival. One of the reasons for the resilience of pancreatic cancer towards intensive treatment is that the cancer is capable of high jacking the immune system: during disease progression the immune system is converted from a system that attacks tumor cells into a support structure for the cancer, exerting trophic actions on the cancer cells. This turn-around of immune system action is achieved through mobilization and activation of regulatory T cells, myeloid derived suppressor cells, tumor-associated macrophages and fibroblasts, all of which suppress CD8 T cells and NK cells. This immune suppression occurs both through the expression of tolerance-inducing cell surface molecules, such as PD-L1, as well as through the production of "tolerogenic" cytokines, such as IL-10 and TGF-β. Based on the accumulating insight into the importance of the immune system for the outcome of pancreatic cancer patients multiple new immunotherapeutic approaches against pancreatic cancer are being currently tested in clinical trials. In this review we give an overview of both the immune escaping mechanisms of pancreatic cancer as well as the new immune related therapeutic strategies currently being tested in pancreatic cancer clinical trials.

Antitumor immune response of dendritic cells (DCs) expressing tumor-associated antigens derived from induced pluripotent stem cells: in comparison to bone marrow-derived DCs

It is generally accepted that the difficulty in obtaining a sufficient number of functional dendritic cells (DCs) is a serious problem in DC-based immunotherapy. Therefore, we used the induced pluripotent stem (iPS) cell-derived DCs (iPSDCs). If the therapeutic efficacy of iPSDCs is equivalent to that of bone marrow-derived DCs (BMDCs), then the aforementioned problems may be solved. In our study, we induced iPSDCs from iPS cells and examined the capacity for maturation of iPSDCs compared to that of BMDCs in addition to the capacity for migration of iPSDCs to regional lymph nodes. We adenovirally transduced the hgp100 gene, natural tumor antigens, into DCs and immunized mice once with the genetically modified DCs. The cytotoxic activity of CD8 (+) cytotoxic T lymphocytes (CTLs) was assayed using a (51) Cr-release assay. The therapeutic efficacy of the vaccination was examined in a subcutaneous tumor model. Our results showed that iPSDCs have an equal capacity to BMDCs in terms of maturation and migration. Furthermore, hgp100-specific CTLs were generated in mice immunized with genetically modified iPSDCs. These CTLs exhibited as high a level of cytotoxicity against B16 cells as BMDCs. Moreover, vaccination with the genetically modified iPSDCs achieved as high a level of therapeutic efficacy as vaccination with BMDCs. Our study clarified experimentally that genetically modified iPSDCs have an equal capacity to BMDCs in terms of tumor-associated antigen-specific therapeutic antitumor immunity. This vaccination strategy may therefore be useful for future clinical application as a cancer vaccine.

Identification of potential biomarkers from microarray experiments using multiple criteria optimization

Microarray experiments are capable of determining the relative expression of tens of thousands of genes simultaneously, thus resulting in very large databases. The analysis of these databases and the extraction of biologically relevant knowledge from them are challenging tasks. The identification of potential cancer biomarker genes is one of the most important aims for microarray analysis and, as such, has been widely targeted in the literature. However, identifying a set of these genes consistently across different experiments, researches, microarray platforms, or cancer types is still an elusive endeavor. Besides the inherent difficulty of the large and nonconstant variability in these experiments and the incommensurability between different microarray technologies, there is the issue of the users having to adjust a series of parameters that significantly affect the outcome of the analyses and that do not have a biological or medical meaning. In this study, the identification of potential cancer biomarkers from microarray data is casted as a multiple criteria optimization (MCO) problem. The efficient solutions to this problem, found here through data envelopment analysis (DEA), are associated to genes that are proposed as potential cancer biomarkers. The method does not require any parameter adjustment by the user, and thus fosters repeatability. The approach also allows the analysis of different microarray experiments, microarray platforms, and cancer types simultaneously. The results include the analysis of three publicly available microarray databases related to cervix cancer. This study points to the feasibility of modeling the selection of potential cancer biomarkers from microarray data as an MCO problem and solve it using DEA. Using MCO entails a new optic to the identification of potential cancer biomarkers as it does not require the definition of a threshold value to establish significance for a particular gene and the selection of a normalization procedure to compare different experiments is no longer necessary.

Pancreatic tumors and immature immunosuppressive myeloid cells in blood and spleen: role of inhibitory co-stimulatory molecules PDL1 and CTLA4. An in vivo and in vitro study

BACKGROUND

Blood and spleen expansion of immature myeloid cells (IMCs) might compromise the immune response to cancer. We studied in vivo circulating and splenic T lymphocyte and IMC subsets in patients with benign and malignant pancreatic diseases. We ascertained in vitro whether pancreatic adenocarcinoma (PDAC)-associated IMC subsets are induced by tumor-derived soluble factors and whether they are immunosuppressive focusing on the inhibitory co-stimulatory molecules PDL1 and CTLA4.

METHODOLOGY AND PRINCIPAL FINDINGS

103 pancreatic and/or splenic surgical patients were enrolled including 52 PDAC, 10 borderline and 10 neuroendocrine tumors (NETs). Lymphocytes and IMCs were analysed by flow cytometry in blood, in spleen and in three PDAC cell conditioned (CM) or non conditioned PBMC. PDL1 and CTLA4 were studied in 30 splenic samples, in control and conditioned PBMC. IMCs were FACS sorted and co-coltured with allogenic T lymphocytes. In PDAC a reduction was found in circulating CD8(+) lymphocytes (p = 0.004) and dendritic cells (p = 0.01), which were reduced in vitro by one PDAC CM (Capan1; p = 0.03). Blood myeloid derived suppressive cells (MDSCs) CD33(+)CD14(-)HLA-DR(-) were increased in PDAC (p = 0.022) and were induced in vitro by BxPC3 CM. Splenic dendritic cells had a higher PDL1 expression (p = 0.007), while CD33(+)CD14(+)HLA-DR(-) IMCs had a lower CTLA4 expression (p = 0.029) in PDAC patients. In vitro S100A8/A9 complex, one of the possible inflammatory mediators of immune suppression in PDAC, induced PDL1 (p = 0.018) and reduced CTLA4 expression (p = 0.028) among IMCs. IMCs not expressing CTLA4 were demonstrated to be immune suppressive.

CONCLUSION

In PDAC circulating dendritic and cytotoxic T cells are reduced, while MDSCs are increased and this might favour tumoral growth and progression. The reduced CTLA4 expression found among splenic IMCs of PDAC patients was demonstrated to characterize an immune suppressive phenotype and to be consequent to the direct exposure of myeloid cells to pancreatic cancer derived products, S100A8/A9 complex in particular.

Dendritic cells and their role in tumor immunosurveillance

Dendritic cells (DCs) comprise a heterogeneous population of cells that play a key role in initiating, directing and regulating adaptive immune responses, including those critically involved in tumor immunosurveillance. As a riposte to the central role of DCs in the generation of antitumor immune responses, tumors have developed various mechanisms which impair the immunostimulatory functions of DCs or even instruct them to actively contribute to tumor growth and progression. In the first part of this review we discuss general aspects of DC biology, including their origin, subtypes, immature and mature states, and functional plasticity which ensures a delicate balance between active immune response and immune tolerance. In the second part of the review we discuss the complex interactions between DCs and the tumor microenvironment, and point out the challenges faced by DCs during the recognition of tumor Ags. We also discuss the role of DCs in tumor angiogenesis and vasculogenesis.

Therapeutic potential of semi-mature dendritic cells for tolerance induction

Dendritic cells (DCs) are major players in the control of adaptive tolerance and immunity. Therefore, their specific generation and adoptive transfer into patients or their in vivo targeting is attractive for clinical applications. While injections of mature immunogenic DCs are tested in clinical trials, tolerogenic DCs still are awaiting this step. Besides the tolerogenic potential of immature DCs, also semi-mature DCs can show tolerogenic activity but both types also bear unfavorable features. Optimal tolerogenic DCs, their molecular tool bar, and their use for specific diseases still have to be defined. Here, the usefulness of in vitro generated and adoptively transferred semi-mature DCs for tolerance induction is outlined. The in vivo targeting of semi-mature DCs as represented by steady state migratory DCs are discussed for treatment of autoimmune diseases and allergies. First clinical trials with transcutaneous allergen application may point to their therapeutic use in the future.

Pancreatic ductal adenocarcinoma: a review of immunologic aspects

With the continued failures of both early diagnosis and treatment options for pancreatic cancer, it is now time to comprehensively evaluate the role of the immune system on the development and progression of pancreatic cancer. It is important to develop strategies that harness the molecules and cells of the immune system to treat this disease. This review will focus primarily on the role of immune cells in the development and progression of pancreatic ductal adenocarcinoma and to evaluate what is known about the interaction of immune cells with the tumor microenvironment and their role in tumor growth and metastasis. We will conclude with a brief discussion of therapy for pancreatic cancer and the potential role for immunotherapy. We hypothesize that the role of the immune system in tumor development and progression is tissue specific. Our hope is that better understanding of this process will lead to better treatments for this devastating disease.