MUC-1 epithelial tumor mucin-based immunity and cancer vaccines

Site-Specific Modification of Virus-Like Particles for Exogenous Tumor Antigen Display and Minimizing Preexisting Immunity

The widespread preexisting immunity against virus-like particles (VLPs) seriously limits the applications of VLPs as vaccine vectors. Enabling technology for exogenous antigen display should not only ensure the assembly ability of VLPs and site-specific modification, but also consider the effect of preexisting immunity on the behavior of VLPs in vivo. Here, combining genetic code expansion technique and synthetic biology strategy, a site-specific modification method for hepatitis B core (HBc) VLPs via incorporating azido-phenylalanine into the desired positions is described. Through modification position screening, it is found that HBc VLPs incorporated with azido-phenylalanine at the main immune region can effectively assemble and rapidly conjugate with the dibenzocycolctyne-modified tumor-associated antigens, mucin-1 (MUC1). The site-specific modification of HBc VLPs not only improves the immunogenicity of MUC1 antigens but also shields the immunogenicity of HBc VLPs themselves, thereby activating a strong and persistent anti-MUC1 immune response even in the presence of preexisting anti-HBc immunity, which results in the efficient tumor elimination in a lung metastatic mouse model. Together, these results demonstrate the site-specific modification strategy enabled HBc VLPs behave as a potent antitumor vaccine and this strategy to manipulate immunogenicity of VLPs may be suitable for other VLP-based vaccine vectors.

Armored modified vaccinia Ankara in cancer immunotherapy

Cancer immunotherapy relies on unleashing the patient´s immune system against tumor cells. Cancer vaccines aim to stimulate both the innate and adaptive arms of immunity to achieve durable clinical responses. Some roadblocks for a successful cancer vaccine in the clinic include the tumor antigen of choice, the adjuvants employed to strengthen antitumor-specific immune responses, and the risks associated with enhancing immune-related adverse effects in patients. Modified vaccinia Ankara (MVA) belongs to the family of poxviruses and is a versatile vaccine platform that combines several attributes crucial for cancer therapy. First, MVA is an excellent inducer of innate immune responses leading to type I interferon secretion and induction of T helper cell type 1 (Th1) immune responses. Second, it elicits robust and durable humoral and cellular immunity against vector-encoded heterologous antigens. Third, MVA has enormous genomic flexibility, which allows for the expression of multiple antigenic and costimulatory entities. And fourth, its replication deficit in human cells ensures a excellent safety profile. In this review, we summarize the current understanding of how MVA induces innate and adaptive immune responses. Furthermore, we will give an overview of the tumor-associated antigens and immunomodulatory molecules that have been used to armor MVA and describe their clinical use. Finally, the route of MVA immunization and its impact on therapeutic efficacy depending on the immunomodulatory molecules expressed will be discussed.

IEDB and CEDAR: Two Sibling Databases to Serve the Global Scientific Community

Various methodologies have been utilized to analyze epitope-specific responses in the context of non-self-antigens, such as those associated with infectious diseases and allergies, and in the context of self-antigens, such as those associated with transplantation, autoimmunity, and cancer. Further to this, epitope-specific data, and its associated immunological context, are crucial to training and developing predictive algorithms and pipelines for the development of specific vaccines and diagnostics. In this chapter, we describe the methodology utilized to derive two sibling resources, the Immune Epitope Database (IEDB) and Cancer Epitope Database and Analysis Resource (CEDAR), to specifically host this data, and make them freely available to the scientific community.

Nonspecific nuclear uptake of anti-MUC1 aptamers by dead cells: the role of cell viability monitoring in aptamer targeting of membrane-bound protein cancer biomarkers

Most aptamers targeting cell-expressed antigens are intended for in vivo application, however, these sequences are commonly generated in vitro against synthetic oligopeptide epitopes or recombinant proteins. As these in vitro analogues frequently do not mimic the in vivo target within an endogenous environment, the evolved aptamers are often prone to nonspecific binding. The presence of dead cells and cellular debris further complicate aptamer targeting, due to their high nonspecific affinities to single-stranded DNA. Despite these known limitations, assessment of cell viability and/or the removal of dead cells is rarely applied as part of the methodology during in vivo testing of aptamer binding. Furthermore, the extent and route(s) by which dead cells uptake existing aptamers remains to be determined in the literature. For this purpose, the previously reported aptamer sequences 5TR1, 5TR4, 5TRG2 and S22 - enriched against the MUC1 tumour marker of the mucin glycoprotein family - were used as model sequences to evaluate the influence of cell viability and the presence of nontarget cell-expressed protein on aptamer binding to the MUC1 expressing human cancer cell lines MCF-7, Hs578T, SW480, and SW620. From fluorescence microscopy analysis, all tested aptamers demonstrated extensive nonspecific uptake within the nuclei of dead cells with compromised membrane integrities. Using fluorescent-activated cell sorting (FACS), the inclusion of excess double-stranded DNA as a blocking agent showed no effect on nonspecific aptamer uptake by dead cells. Further nonspecific binding to cell-membrane bound and intracellular protein was evident for each aptamer sequence, as assessed by southwestern blotting and FACS. These factors likely contributed to the ∼120-fold greater binding response of the 5TR1 aptamer to dead MCF-7 cells over equivalent live cell populations. The identification of dead cells and cellular debris using viability stains and the subsequent exclusion of these cells from FACS analysis was identified as an essential requirement for the evaluation of aptamer binding specificity to live cell populations of the cancer cell lines MCF-7, Hs578T and SW480. The research findings stress the importance of dead cell uptake and more comprehensive cell viability screening to validate novel aptamer sequences for diagnostic and therapeutic application.

Adoptive Cell Therapy in Hepatocellular Carcinoma: Biological Rationale and First Results in Early Phase Clinical Trials

The mortality of hepatocellular carcinoma (HCC) is quickly increasing worldwide. In unresectable HCC, the cornerstone of systemic treatments is switching from tyrosine kinase inhibitors to immune checkpoints inhibitors (ICI). Next to ICI, adoptive cell transfer represents another promising field of immunotherapy. Targeting tumor associated antigens such as alpha-fetoprotein (AFP), glypican-3 (GPC3), or New York esophageal squamous cell carcinoma-1 (NY-ESO-1), T cell receptor (TCR) engineered T cells and chimeric antigen receptors (CAR) engineered T cells are emerging as potentially effective therapies, with objective responses reported in early phase trials. In this review, we address the biological rationale of TCR/CAR engineered T cells in advanced HCC, their mechanisms of action, and results from recent clinical trials.

89Zr-Labeled AR20.5: A MUC1-Targeting ImmunoPET Probe

High expression levels of the tumor-associated antigen MUC1 have been correlated with tumor aggressiveness, poor response to therapy, and poor survival in several tumor types, including breast, pancreatic, and epithelial ovarian cancer. Herein, we report the synthesis, characterization, and in vivo evaluation of a novel radioimmunoconjugate for the immuno-positron emission tomography (immunoPET) imaging of MUC1 expression based on the AR20.5 antibody. To this end, we modified AR20.5 with the chelator desferrioxamine (DFO) and labeled it with the positron-emitting radiometal zirconium-89 (t_1/2 ~3.3 d) to produce [⁸⁹Zr]Zr-DFO-AR20.5. In subsequent in vivo experiments in athymic nude mice bearing subcutaneous MUC1-expressing ovarian cancer xenografts, [⁸⁹Zr]Zr-DFO-AR20.5 clearly delineated tumor tissue, producing a tumoral activity concentration of 19.1 ± 6.4 percent injected dose per gram (%ID/g) at 120 h post-injection and a tumor-to-muscle activity concentration ratio of 42.4 ± 10.6 at the same time point. Additional PET imaging experiments in mice bearing orthotopic MUC1-expressing ovarian cancer xenografts likewise demonstrated that [⁸⁹Zr]Zr-DFO-AR20.5 enables the visualization of tumor tissue-including metastatic lesions-with promising tumor-to-background contrast.

Melanoma vaccines: clinical status and immune endpoints

It has been known for decades that the immune system can be spontaneously activated against melanoma. The presence of tumor infiltrating lymphocytes in tumor deposits is a positive prognostic factor. Cancer vaccination includes approaches to generate, amplify, or skew antitumor immunity. To accomplish this goal, tested approaches involve administration of tumor antigens, antigen presenting cells or other immune modulators, or direct modulation of the tumor. Because the success of checkpoint blockade can depend in part on an existing antitumor response, cancer vaccination may play an important role in future combination therapies. In this review, we discuss a variety of melanoma vaccine approaches and methods to determine the biological impact of vaccination.

Immune precision medicine for cancer: a novel insight based on the efficiency of immune effector cells

Cancer cell growth is associated with immune surveillance failure. Nowadays, restoring the desired immune response against cancer cells remains a major therapeutic strategy. Due to the recent advances in biological knowledge, efficient therapeutic tools have been developed to support the best bio-clinical approaches for immune precision therapy. One of the most important successes in immune therapy is represented by the applicational use of monoclonal antibodies, particularly the use of rituximab for B-cell lymphoproliferative disorders. More recently, other monoclonal antibodies have been developed, to inhibit immune checkpoints within the tumor microenvironment that limit immune suppression, or to enhance some immune functions with immune adjuvants through different targets such as Toll-receptor agonists. The aim is to inhibit cancer proliferation by the diminishing/elimination of cancer residual cells and clinically improving the response duration with no or few adverse effects. This effect is supported by enhancing the number, functions, and activity of the immune effector cells, including the natural killer (NK) lymphocytes, NKT-lymphocytes, γδ T-lymphocytes, cytotoxic T-lymphocytes, directly or indirectly through vaccines particularly with neoantigens, and by lowering the functions of the immune suppressive cells. Beyond these new therapeutics and their personalized usage, new considerations have to be taken into account, such as epigenetic regulation particularly from microbiota, evaluation of transversal functions, particularly cellular metabolism, and consideration to the clinical consequences at the body level. The aim of this review is to discuss some practical aspects of immune therapy, giving to clinicians the concept of immune effector cells balancing between control and tolerance. Immunological precision medicine is a combination of modern biological knowledge and clinical therapeutic decisions in a global vision of the patient.

MUC1 Story: Great Expectations, Disappointments and the Renaissance

In the course of studying human mucin MUC1, the attitude towards this molecule has been changing time and again. Initially, the list of presumable functions of MUC1 was restricted to protecting and lubricating epithelium. To date, it is assumed to play an important role in cell signaling as well as in all stages of oncogenesis, from malignant cell transformation to tumor dissemination. The story of MUC1 is full of hopes and disappointments. However, the scientific interest to MUC1 has never waned, and the more profoundly it has been investigated, the clearer its hidden potential turned to be disclosed. The therapeutic potential of mucin MUC1 has already been noted by various scientific groups at the early stages of research. Over forty years ago, the first insights into MUC1 functions became a strong ground for considering this molecule as potential target for anticancer therapy. Therefore, this direction of research has always been of particular interest and practical importance. More than 200 papers on MUC1 were published in 2016; the majority of them are dedicated to MUC1-related anticancer diagnostics and therapeutics. Here we review the history of MUC1 studies from the very first attempts to reveal its functions to the ongoing renaissance.

Imprint of parity and age at first pregnancy on the genomic landscape of subsequent breast cancer

Background

Although parity and age at first pregnancy are among the most known extrinsic factors that modulate breast cancer risk, their impact on the biology of subsequent breast cancer has never been explored in depth. Recent data suggest that pregnancy-induced tumor protection is different according to breast cancer subtypes, with parity and young age at first pregnancy being associated with a marked reduction in the risk of developing luminal subtype but not triple negative breast cancer. In this study, we investigated the imprint of parity and age at first pregnancy on the pattern of somatic mutations, somatic copy number alterations, transcriptomic profiles, and tumor immune microenvironment by assessing tumor-infiltrating lymphocytes (TILs) levels of subsequent breast cancer.

Methods

A total of 313 patients with primary breast cancer with available whole genome, RNA sequencing, and TILs data were included in this study. We used a multivariate analysis adjusted for age at diagnosis, pathological stage, molecular subtypes, and histological subtypes. We compared nulliparous vs. parous, late parous vs. early parous, and nulliparous vs. pregnancy-associated breast cancer (PABC) patients. Late and early parous patients were grouped by using the median age at first pregnancy. PABC was defined as patients diagnosed up to 10 years postpartum.

Results

Genomic alterations of breast cancer were associated with age at first pregnancy but not with parity status alone. Independently of clinicopathological features, early parous patients developed tumors characterized by a higher number of Indels (P_adj = 0.002), a lower frequency of CDH1 mutations (1.2% vs. 12.7%; P_adj = 0.013), a higher frequency of TP53 mutations (50% vs. 22.5%; P_adj = 0.010), and MYC amplification (28% vs. 7%; P_adj = 0.008). PABC were associated with increased TILs infiltration (P_adj = 0.0495).

Conclusions

These findings highlight an unprecedented link between reproductive history and the genomic landscape of subsequent breast cancer. We further hypothesize that TP53-mutant premalignant lesions could be less susceptible to the protective effect of an early parity, which might explain the difference of parity-induced protection according to breast cancer subtypes. This work also advocates that reproductive history should be routinely collected in future large-scale genomic studies addressing the biology of female cancers.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1111-6) contains supplementary material, which is available to authorized users.

Glycosylation of MUC1 influences the binding of a therapeutic antibody by altering the conformational equilibrium of the antigen

In cancer cells, the glycoprotein Mucin 1 (MUC1) undergoes abnormal, truncated glycosylation. The truncated glycosylation exposes cryptic peptide epitopes that can be recognized by antibodies. Since these immunogenic regions are cancer specific, they represent ideal targets for therapeutic antibodies. We investigated the role of tumor-specific glycosylation on antigen recognition by the therapeutic antibody AR20.5. We explored the affinity of AR20.5 to a synthetic cancer-specific MUC1 glycopeptide and peptide. The antibody bound to the glycopeptide with an order of magnitude stronger affinity than the naked peptide. Given these results, we postulated that AR20.5 must specifically bind the carbohydrate as well as the peptide. Using X-ray crystallography, we examined this hypothesis by determining the structure of AR20.5 in complex with both peptide and glycopeptide. Surprisingly, the structure revealed that the carbohydrate did not form any specific polar contacts with the antibody. The high affinity of AR20.5 for the glycopeptide and the lack of specific binding contacts support a hypothesis that glycosylation of MUC1 stabilizes an extended bioactive conformation of the peptide recognized by the antibody. Since high affinity binding of AR20.5 to the MUC1 glycopeptide may not driven by specific antibody-antigen contacts, but rather evidence suggests that glycosylation alters the conformational equilibrium of the antigen, which allows the antibody to select the correct conformation. This study suggests a novel mechanism of antibody-antigen interaction and also suggests that glycosylation of MUC1 is important for the generation of high affinity therapeutic antibodies.

Hormonal Regulation of MUC1 Expression

Several circulating mucinous markers, including CA 15.3, MCA, CA 459, CASA, and Truquant BR, are secreted products of the polymorphic MUC1 gene, and are used as diagnostic tools in patients with breast cancer. In clinical practice the measurement of the levels of these markers in the blood can give important information on the tumor's response to treatment and its biological behavior during disease monitoring. Since the marker levels reflect the activity of the tumor, it is important to know all factors influencing the production/secretion and the blood concentrations of MUC1 mucin. Recent findings suggest that MUC1 gene expression is regulated by steroid hormones and other substances present in the serum. Such observations are very important not only because of their biological significance but also for their clinical implications, as one approach to breast cancer therapy is based on chemical hormone manipulation. Nevertheless, we have preliminarily demonstrated that endocrine treatment in breast cancer patients does not influence the circulating CA 15.3 serum levels, so changes in marker levels are related only to the clinical evolution of the tumor.

Human MUC1 Mucin: A Multifaceted Glycoprotein

Human MUC1 mucin, a membrane-bound glycoprotein, is a major component of the ductal cell surface of normal glandular cells. MUC1 is overexpressed and aberrantly glycosylated in carcinoma cells. The role MUC1 plays in cancer progression represents two sides of one coin: on the one hand, loss of polarity and overexpression of MUC1 in cancer cells interferes with cell adhesion and shields the tumor cell from immune recognition by the cellular arm of the immune system, thus favoring metastases; on the other hand, MUC1, in essence a self-antigen, is displaced and altered in malignancy and induces immune responses. Tumor-associated MUC1 has short carbohydrate sidechains and exposed epitopes on its peptide core; it gains access to the circulation and comes into contact with the immune system provoking humoral and cellular immune responses. Natural antibodies to MUC1 present in the circulation of cancer patients may be beneficial to the patient by restricting tumor growth and dissemination: early stage breast cancer patients with a humoral response to MUC1 have a better disease-specific survival. Several MUC1 peptide vaccines, differing in vectors, carrier proteins and adjuvants, have been tested in phase I clinical trials. They are capable of inducing predominantly humoral responses to the antigen, but evidence that these immune responses may be effective against the tumor in humans is still scarce.

Detection of Circulating Mammary Mucin (MUC1) and MUC1 Immune Complexes (MUC1-CIC) in Healthy Women

There is convincing epidemiological evidence that multiparity provides protection against the development of breast cancer. In the present study we evaluated the levels of MUC1 and MUC1 circulating immune complexes (MUC1-CIC) in 135 serum samples obtained from healthy women. The study population included 13 women who had never been pregnant, 31 primiparous pregnant women, 36 multiparous pregnant women who had lactated, 5 multiparous pregnant women who had never lactated, 24 multiparous non-pregnant women who were lactating at the time of the study, 24 multiparous non-pregnant women who had lactated, and 2 multiparous non-pregnant women who had never lactated. The purpose of this work was to detect MUC1 variations during pregnancy and lactation as well as to study the possible induction of a humoral immune response against MUC1 in these conditions. We employed ELISA techniques to measure MUC1 (CASA test) and MUC1-CIC (IgM and IgG) using two anti-MUC1 monoclonal antibodies (MAbs): C595 and SM3. Statistical analysis was performed using the ANOVA test. The pooled results pertaining to pregnant versus non-pregnant women were compared and significant differences were observed in MUC1 and MUC1-CIC-IgM levels detected with both MAbs; the MUC1-CIC-IgG levels detected with C595 were increased in the pregnant group while the MUC1-CIC-IgG levels detected with SM3 did not show any significant differences. When the results were compared between lactating and non-lactating women, no significant differences were found. In conclusion, MUC1 and MUC1-CIC-IgM, detected with both MAbs, and MUC1-CIC-IgG levels detected with the MAb C595 are apparently induced by pregnancy.

Mucus and Mucins: do they have a role in the inhibition of the human immunodeficiency virus?

Background

Mucins are large O-linked glycosylated proteins which give mucus their gel-forming properties. There are indications that mucus and mucins in saliva, breast milk and in the cervical plug inhibit the human immunodeficiency virus (HIV-1) in an in vitro assay.

Main body of abstract

Crude mucus gels form continuous layers on the epithelial surfaces of the major internal tracts of the body and protect these epithelial surfaces against aggressive luminal factors such as hydrochloric acid and pepsin proteolysis in the stomach lumen, the movement of hard faecal pellets in the colon at high pressure, the effects of shear against the vaginal epithelium during intercourse and the presence of foreign substances in the respiratory airways. Tumour-associated epitopes on mucins make them suitable as immune-targets on malignant epithelial cells, rendering mucins important as diagnostic and prognostic markers for various diseases, even influencing the design of mucin-based vaccines.

Sub-Saharan Africa has the highest prevalence of HIV-AIDS in the world. The main points of viral transmission are via the vaginal epithelium during sexual intercourse and mother-to-child transmission during breast-feeding. There have been many studies showing that several body fluids have components that prevent the transmission of HIV-1 from infected to non-infected persons through various forms of contact.

Crude saliva and its purified mucins, MUC5B and MUC7, and the purified mucins from breast milk, MUC1 and MUC4 and pregnancy plug cervical mucus (MUC2, MUC5AC, MUC5B and MUC6), inhibit HIV-1 in an in vitro assay. There are conflicting reports of whether crude breast-milk inhibits HIV-1 in an in vitro assay. However studies with a humanised BLT mouse show that breast-milk does inhibit HIV and that breast-feeding is still advisable even amongst HIV-positive women in under-resourced areas, preferably in conjunction with anti-retroviral treatment.

Conclusion

These findings raise questions of how such a naturally occurring biological substance such as mucus, with remarkable protective properties of epithelial surfaces against aggressive luminal factors in delicate locations, could be used as a tool in the fight against HIV-AIDS, which has reached epidemic proportions in sub-Saharan Africa.

Parity improves anti-tumor immunity in breast cancer patients

Compared to nulliparous women, parous women have an up to 50% lower lifetime risk of developing breast cancer. An endogenous mechanism to prevent the development of cancer is the destruction of tumor cells by T cells that recognize tumor-associated antigens (TAA). Since a number of TAA are also highly present in the breast and placenta of pregnant women, we investigated the induction and characteristics of spontaneous T cell responses against TAA during pregnancy. To this end, we collected peripheral blood from healthy nulliparous, primigravid and parous women, as well as from breast cancer patients. IFN-γ ELISpot assays were performed to measure the intensity and specificity of T cell responses against 11 different TAA. The impact of TAA-specific Treg cells on anti-TAA responses was assessed by performing the assay before and after depletion of CD4⁺CD25⁺ T cells. The antigenic specificities of these Treg cells were analyzed by the Treg specificity assay. Furthermore, we conducted flow cytometric analyses to determine the memory phenotype and cytokine secretion profile of TAA-specific T cells. Our results demonstrate that pregnancy induces functional and long-lived memory and effector T cells that react against multiple TAA. These persist for many decades in parous females, but are not found in age-matched females without children. We also detected TAA-specific Treg cells, which suppressed strong effector T cell responses after delivery. Nulliparous breast cancer patients displayed median TAA-specific effector T cell responses to be decreased threefold compared to parous patients, which could be restored in vitro after depletion of Treg cells.

Cytotoxic T cell responses are enhanced by antigen design involving the presentation of MUC1 peptide on cholera toxin B subunit

Induction of cytotoxic T lymphocytes (CTL) is critical to cancer vaccine based immunotherapy. Efforts to elicit CTLs against tumor MUC1 with peptide based vaccine have not been successful in clinical application. We have design a MUC1 vaccine by replacing B cell epitope of CTB with MUC1 VNTR peptide. Immunization with hybrid CTB-MUC1 plus aluminum hydroxide and CpG adujuvant (CTB-MUC1-Alum-CpG) induce MUC1-specific CTLs in mice. Moreover, this vaccination can prevent tumor growth and reduce tumor burden in MUC1⁺B16 mice model. Meanwhile, CTB-MUC1-Alum-CpG vaccination can promote Th1 cells and CD8+ T cells inflate to tumor tissue. Our approach might be applicable to other cancer vaccine design.

Synthesis of a Liposomal MUC1 Glycopeptide-Based Immunotherapeutic and Evaluation of the Effect of l-Rhamnose Targeting on Cellular Immune Responses

Generation of a CD8(+) response to extracellular antigen requires processing of the antigen by antigen presenting cells (APC) and cross-presentation to CD8(+) T cell receptors via MHC class I molecules. Cross-presentation is facilitated by efficient antigen uptake followed by immune-complex-mediated maturation of the APCs. We hypothesize that improved antigen uptake of a glycopeptide sequence containing a CD8(+) T cell epitope could be achieved by delivering it on a liposome surface decorated with an immune complex-targeting ligand, an l-Rhamnose (Rha) epitope. We synthesized a 20-amino-acid glycopeptide TSAPDT(GalNAc)RPAPGSTAPPAHGV from the variable number tandem repeat region of the tumor marker MUC1 containing an N-terminal azido moiety and a tumor-associated α-N-acetyl galactosamine (GalNAc) at the immunogenic DTR motif. The MUC1 antigen was attached to Pam3Cys, a Toll-like receptor-2 ligand via copper(I)-catalyzed azido-alkyne cycloaddition (CuAAc) chemistry. The Rha-decorated liposomal Pam3Cys-MUC1-Tn 4 vaccine was evaluated in groups of C57BL/6 mice. Some groups were previously immunized to generate anti-Rha antibodies. Anti-Rha antibody expressing mice that received the Rha liposomal vaccine showed higher cellular immunogenicity compared to the control group while maintaining a strong humoral response.

Cancer vaccines

Cancer vaccines are designed to promote tumor specific immune responses, particularly cytotoxic CD8 positive T cells that are specific to tumor antigens. The earliest vaccines, which were developed in 1994-95, tested non-mutated, shared tumor associated antigens that had been shown to be immunogenic and capable of inducing clinical responses in a minority of people with late stage cancer. Technological developments in the past few years have enabled the investigation of vaccines that target mutated antigens that are patient specific. Several platforms for cancer vaccination are being tested, including peptides, proteins, antigen presenting cells, tumor cells, and viral vectors. Standard of care treatments, such as surgery and ablation, chemotherapy, and radiotherapy, can also induce antitumor immunity, thereby having cancer vaccine effects. The monitoring of patients' immune responses at baseline and after standard of care treatment is shedding light on immune biomarkers. Combination therapies are being tested in clinical trials and are likely to be the best approach to improving patient outcomes.

Triple-negative breast cancer: investigating potential molecular therapeutic target

INTRODUCTION

Triple-negative breast cancer (TNBC) makes up about 10 - 20% of all breast cancers and the lack of hormone receptors and human epidermal growth factor receptor-2/Neu expression is responsible for poor prognosis, no targeted therapies and trouble in the clinical management. Tumor heterogeneity, also within the same tumor, is a major cause for this difficulty. Based on the introduction of new biological drugs against different kinds of tumor, many efforts have been made for classification of genetic alterations present in TNBC, leading to the identification of several oncogenes and tumor suppressor genes involved in breast cancer carcinogenesis.

AREAS COVERED

In this review we investigated the molecular alteration present in TNBC which could lead to the creation of new targeted therapies in the future, with the aim to counteract this disease in the most effective way.

EXPERT OPINION

In this context some hormone receptors like G-protein-coupled receptor 30 and androgen receptors may be a fascinating area to investigate; also, angiogenesis, represented not only by the classical VEGF/VEGFR relationship, but also by other molecules, like semaphorins, fibroblast growth factor and heparin-binding-EGF-like, is a mechanism in which new developments are expected. In this perspective, one technique that may show promise is the gene therapy; in particular the gene transfer could correct abnormal genetic function in cancer cells.

The state of the art in non-small cell lung cancer immunotherapy

Once considered an ineffective modality in lung cancer, immunotherapy has emerged as one of the most promising therapeutic strategies for this lethal disease. The past few years have seen a plethora of clinical trials evaluating various immunotherapeutic approaches in lung cancer. This article discusses the current status of immunotherapy in non-small cell lung cancer with a review of completed studies and ongoing trials.

Humoral immune response against tumoral mucin 1 (MUC1) in breast cancer patients

The aim of this study was to elucidate whether the IgG humoral immune response to breast cancer cells is directed to the aberrant mucin-1 (MUC1) associated to this type of cancer. To this aim, an adaptation of immunohistochemistry (IHC) was performed on samples of 45 breast cancer tissues, 12 benign disease tissues, and 31 normal tissues, incubated with matched serum samples from the same patients. Each serum sample was also incubated, with a modified immunocytochemistry (ICC), with MCF7 cells. In both techniques, serum was employed instead of the primary antibody. In the case of IHC, the reactivity with sera diminished when added after previous incubation of the tumor/tissue with an anti-MUC1 mAb; the reduction in reactivity was: from 93% to 44% in breast cancer tissues, and from 100% to 67% in benign disease tissues. The reactivity of normal samples (36%) remained unchanged. In the case of ICC, the reactivity with sera decreased after incubation with anti-MUC1 mAb from 71% to 16% in breast cancer tissues, from 83% to 0% in benign disease tissues, and from 52% to 10% in normal serum samples. These results were confirmed employing siRNA MUC1 transient gene knockdown. By Western blot analysis -
after immunoprecipitation (IP) of the circulating MUC1- and ELISA, the TF antigen was detected in circulating MUC1 in all breast cancer and benign samples while Tn was detected in 38% of the samples.
The existence of IgG autoantibodies against aberrantly glycosylated MUC1 may have a protective role and may contribute to a better prognosis in some patients. Enhancement of this natural immune response may constitute an alternative therapeutic strategy.

MUC1 is expressed at high frequency in early-stage basal-like triple-negative breast cancer

Triple-negative breast cancer comprises 10% to 15% of newly diagnosed breast cancer and lacks expression of the estrogen, progesterone, and human epidermal growth factor receptor 2/neu receptors. Many such tumors are basal like, a molecular intrinsic subtype of breast cancer associated with poor clinical outcomes. Patients with early-stage basal-like triple-negative breast cancer are at a high risk for relapse and may, therefore, benefit from novel therapies, including immunotherapy. MUC1 is a tumor antigen expressed on adenocarcinomas and represents an ideal target for MUC1-based vaccination. We evaluated 52 cases of early-stage basal-like triple-negative breast cancer for MUC1 expression by immunohistochemistry. The intensity of staining was graded according to the intensity (negative [0], positive [1], or strongly positive [2]) and percentage (0%-100%) of tumor cells staining for MUC1. An overall score of 0 to 2.0 was calculated for each case by multiplying the intensity of staining by the percentage of tumor cells staining positively. Four staining patterns for MUC1 were identified: apical, cytoplasmic, membranous, and combination. Of the 52 cases of basal-like triple-negative breast cancers, 49 (94%) were positive for MUC1 expression. The mean score was 0.90 (range, 0-1.9). Cases were evenly distributed over this range, where most (67%) exhibited moderate to strong MUC1 expression (score, 0.5-1.90), 27% demonstrated weak MUC1 expression, and 6% lacked MUC1 expression. There was a significant difference in MUC1 score and percent MUC1+ cells in favor of the combination pattern. This study indicates that a large proportion of early-stage basal-like triple-negative breast cancer expresses MUC1 and provides a rationale for MUC1-based immunotherapy in this high-risk patient cohort.

Development of a cytokine-modified allogeneic whole cell pancreatic cancer vaccine

Management of patients with pancreatic cancer is a multidisciplinary approach that presents enormous challenges to the clinician. Overall 5-year survival for all patients remains <3%. Symptoms of early pancreas cancer are nonspecific. As such, only a fraction of patients are candidates for surgery. While surgical resection provides the only curative option, most patients will develop tumor recurrence and die of their disease. To date, the clinical benefits of chemotherapy and radiation therapy have been important but have led to modest improvements. Tumor vaccines have the potential to specifically target the needle of pancreas cancer cells amidst the haystack of normal tissue. The discovery of pancreas tumor-specific antigens and the subsequent ability to harness this technology has become an area of intense interest for tumor immunologists and clinicians alike. Without knowledge of specific antigen targets, the whole tumor cell represents the best source of immunizing antigens. This chapter will focus on the development of whole tumor cell vaccine strategies for pancreas cancer.

The development of synthetic antitumour vaccines from mucin glycopeptide antigens

Based on important cell-biological and biochemical results concerning the structural difference between membrane glycoproteins of normal epithelial cells and epithelial tumour cells, tumour-associated glycopeptide antigens have been chemically synthesised and structurally confirmed. Glycopeptide structures of the tandem repeat sequence of mucin MUC1 of epithelial tumour cells constitute the most promising tumour-associated antigens. In order to generate a sufficient immunogenicity of these endogenous structures, usually tolerated by the immune system, these synthetic glycopeptide antigens were conjugated to immune stimulating components: in fully synthetic two-component vaccines either with T-cell peptide epitopes or with Toll-like receptor2 lipopeptide ligands or in three-component vaccines with both these stimulants. Alternatively, the synthetic glycopeptide antigens were coupled to immune stimulating carrier proteins. In particular, MUC1 glycopeptide conjugates with Tetanus toxoid proved to be efficient vaccines inducing very strong immune responses in mice. The antibodies elicited with the fully synthetic vaccines showed selective recognition of the tumour-associated glycopeptides as was shown by neutralisation and micro-array binding experiments. After booster immunisations, most of the immune responses showed the installation of an immunological memory. Immunisation with fully synthetic three-component vaccines induced immune reactions with therapeutic effects in terms of reduction of the tumour burden in mice or in killing of tumour cells in culture, while MUC1 glycopeptide-Tetanus toxoid vaccines elicited antibodies in mice which recognised tumour cells in human tumour tissues. The results achieved so far are considered to be promising for the development of an active immunisation against tumours.

Aberrantly glycosylated MUC1 is expressed on the surface of breast cancer cells and a target for antibody-dependent cell-mediated cytotoxicity

Protein glycosylation often changes during cancer development, resulting in the expression of cancer-associated carbohydrate antigens. In particular mucins such as MUC1 are subject to these changes. We previously identified an immunodominant Tn-MUC1 (GalNAc-α-MUC1) cancer-specific epitope not covered by immunological tolerance in MUC1 humanized mice and man. The objective of this study was to determine if mouse antibodies to this Tn-MUC1 epitope induce antibody-dependent cellular cytotoxicity (ADCC) pivotal for their potential use in cancer immunotherapy. Binding affinity of mAb 5E5 directed to Tn-MUC1 was investigated using BiaCore. The availability of Tn-MUC1 on the surface of breast cancer cells was evaluated by immunohistochemistry, confocal microscopy, and flow cytometry, followed by in vitro assessment of antibody-dependent cellular cytotoxicity by mAb 5E5. Biacore analysis demonstrated high affinity binding (KD = 1.7 nM) of mAb 5E5 to its target, Tn-MUC1. Immunolabelling with mAb 5E5 revealed surface expression of the Tn-MUC1 epitope in breast cancer tissue and cell lines, and mAb 5E5 induced ADCC in two human breast cancer cell lines, MCF7 and T47D. Aberrantly glycosylated MUC1 is expressed on the surface of breast cancer cells and a target for antibody-dependent cell-mediated cytotoxicity suggesting that antibodies targeting glycopeptide epitopes on mucins are strong candidates for cancer-specific immunotherapies.

A different immunologic profile characterizes patients with HER-2-overexpressing and HER-2-negative locally advanced breast cancer: implications for immune-based therapies

Introduction

The clinical efficacy of trastuzumab and taxanes is at least partly related to their ability to mediate or promote antitumor immune responses. On these grounds, a careful analysis of basal immune profile may be capital to dissect the heterogeneity of clinical responses to these drugs in patients with locally advanced breast cancer undergoing neoadjuvant chemotherapy.

Methods

Blood samples were collected from 61 locally advanced breast cancers (36 HER2^- and 25 HER2⁺) at diagnosis and from 23 healthy women. Immunophenotypic profiling of circulating and intratumor immune cells, including regulatory T (Treg) cells, was assessed by flow cytometry and immunohistochemistry, respectively. Serum levels of 10 different cytokines were assessed by multiplex immunoassays. CD8⁺ T cell responses to multiple tumor-associated antigens (TAA) were evaluated by IFN-γ-enzyme-linked immunosorbent spot (ELISPOT). The Student's t test for two tailed distributions and the Wilcoxon two-sample test were used for the statistical analysis of the data.

Results

The proportion of circulating immune effectors was similar in HER2⁺ patients and healthy donors, whereas higher percentages of natural killer and Treg cells and a lower CD4⁺/CD8⁺ T cell ratio (with a prevalence of naïve and central memory CD8⁺ T cells) were observed in HER2^- cases. Higher numbers of circulating CD8⁺ T cells specific for several HLA-A*0201-restricted TAA-derived peptides were observed in HER2⁺ cases, together with a higher prevalence of intratumor CD8⁺ T cells. Serum cytokine profile of HER2⁺ patients was similar to that of controls, whereas HER2^- cases showed significantly lower cytokine amounts compared to healthy women (IL-2, IL-8, IL-6) and HER2⁺ cases (IL-2, IL-1β, IL-8, IL-6, IL-10).

Conclusions

Compared to HER2- cases, patients with HER2-overexpressing locally advanced breast cancer show a more limited tumor-related immune suppression. This may account for the clinical benefit achieved in this subset of patients with the use of drugs acting through, but also promoting, immune-mediated effects.

Dendritic cell therapy in advanced gastric cancer: a promising new hope?

Advanced gastric cancer carries a very poor prognosis when the tumor becomes unresectable. Even with the best currently available chemotherapy regimens the survival rate remains dismal. A recent breakthrough in the treatment paradigm has been the approval of trastuzumab, a monoclonal antibody, in HER2-positive metastatic gastric cancer. A large number of trials are underway using dendritic cells (DCs) in a number of human malignancies and do show a ray of hope in management of these patients. This review attempts to summarize tumor immunology and the current data regarding use of DCs in gastric cancer therapy.

Vaccines for colorectal cancer and renal cell carcinoma

Vaccines have shown promise for the prevention and treatment of solid tumors. Colorectal cancer and renal cell carcinoma are common malignancies that may be amenable to vaccine strategies. This review summarizes target antigens in colorectal and renal cell carcinoma, discusses some of the vaccine approaches in development, and details the results of pivotal phase III trials evaluating therapeutic vaccines in patients with advanced colorectal and renal cell carcinoma. Finally, some of the challenges with vaccine development for colorectal and renal cell carcinoma are described.

Marginating dendritic cells of the tumor microenvironment cross-present tumor antigens and stably engage tumor-specific T cells

The nature and site of tumor-antigen presentation to immune T cells by bone-marrow-derived cells within the tumor microenvironment remains unresolved. We generated a fluorescent mouse model of spontaneous immunoevasive breast cancer and identified a subset of myeloid cells with significant similarity to dendritic cells and macrophages that constitutively ingest tumor-derived proteins and present processed tumor antigens to reactive T cells. Using intravital live imaging, we determined that infiltrating tumor-specific T cells engage in long-lived interactions with these cells, proximal to the tumor. In vitro, these cells capture cytotoxic T cells in signaling-competent conjugates but do not support full activation or sustain cytolysis. The spatiotemporal dynamics revealed here implicate nonproductive interactions between T cells and antigen-presenting cells on the tumor margin.

Identification of HLA-A24-restricted CD8(+) cytotoxic T-cell epitopes derived from mammaglobin-A, a human breast cancer-associated antigen

Human breast cancer-associated antigen, mammaglobin-A (Mam-A), potentially offers a novel therapeutic target as a breast cancer vaccine. In this study, we define the CD8(+) cytotoxic T lymphocyte (CTL) response to Mam-A-derived candidate epitopes presented in the context of HLA-A24 (A*2402). HLA-A24 has a frequency of 72% in Japanese, 27% in Asian Indian, and 18% in Caucasian populations. Using a human leukocyte antigen (HLA)-binding prediction algorithm we identified 7 HLA-A24-restricted Mam-A-derived candidate epitopes (MAA24.1-7). Membrane stabilization studies with TAP-deficient T2 cells transfected with HLA-A2402 (T2.A24) indicated that MAA24.2 (CYAGSGCPL) and MAA24.4 (ETLSNVEVF) have the highest HLA-A24 binding affinity. Further, 2 CD8(+) CTL cell lines generated in vitro against T2.A24 cells individually loaded with Mam-A-derived candidate epitopes demonstrated significant cytotoxic activity against MAA24.2 and MAA24.4. In addition, the same CD8(+) CTL lines lysed the HLA-A24(+)/Mam-A(+) stable transfected human breast cancer cell lines AU565 and MDA-MB-361. However, these CTLs had no cytotoxicity against HLA-A24(-)/Mam-A(+) and HLA-A24(+)/Mam-A(-) breast cancer cell lines. In summary, our results define HLA-A24-restricted, Mam-A-derived, CD8(+) CTL epitopes that can potentially be employed for Mam-A-based breast cancer vaccine therapy to breast cancer patients with HLA-A24 phenotype.

Clinical trials of vaccines for immunotherapy in pancreatic cancer

A greater understanding of the molecular events that trigger oncogenesis and events that negatively regulate immune responses has allowed for the development of targeted therapies with specific vaccines to match tumor antigens coupled with immunotherapy specifically directed against that tumor's immunosuppressive microenvironment. In order to be effective, vaccine therapies need to both expand the immune response to tumors and overcome immunosuppressive microenvironments therein. Specifically, targeted therapy must be personalized for each cancer patient. While the idea of personalized targeted therapy may seem like a daunting task, it may not be that difficult as it could involve a relatively simple genetic test to identify gene mutations and additional immunohistochemical staining of tumors with antibodies directed against markers of negative immune regulation. The additional cost to personalize cancer therapy with these diagnostic tests is relatively small in comparison to the cost afforded to our healthcare system when inappropriate targeting therapies are administered to patients whose tumors do not express the targets of either the vaccine or the immune modulator. Despite the large cost, cancer patients whose tumors lack the targets of these therapies often receive no benefit from the therapy. The most illogical approach is to develop a study design and perform clinical trials of potential novel targeting drugs without knowledge or confirmation that the patients' tumors express the targets. Current cancer trials for pancreatic cancer patients are discussed in this article.

Mixed-phase synthesis of glycopeptides using a N-peptidyl-2,4-dinitrobenzenesulfonamide-thioacid ligation strategy

A strategy for the solid phase peptide synthesis (SPPS) and coupling of N-peptidyl and N-glycopeptidyl 2,4-dinitrobenzenesulfonamides (dNBS) with C-terminal peptidyl thioacids has been developed. The resulting N-dDNBS peptides were coupled to generate longer peptides. Ligation reactions were complete within 15 to 20 min.

Immunotherapy in prostate cancer: emerging strategies against a formidable foe

Recent clinical trials have shown therapeutic vaccines to be promising treatment modalities against prostate cancer. Unlike preventive vaccines that teach the immune system to fight off specific microorganisms, therapeutic vaccines stimulate the immune system to recognize and attack certain cancer-associated proteins. Additional strategies are being investigated that combine vaccines and standard therapeutics, including radiation, chemotherapy, targeted therapies, and hormonal therapy, to optimize the vaccines' effects. Recent vaccine late-phase clinical trials have reported evidence of clinical benefit while maintaining excellent quality of life. One such vaccine, sipuleucel-T, was recently FDA-approved for the treatment of metastatic prostate cancer. Another vaccine, PSA-TRICOM, is also showing promise in completed and ongoing randomized multicenter clinical trials in both early- and late-stage prostate cancer. Clinical results available to date indicate that immune-based therapies could play a significant role in the treatment of prostate and other malignancies.

MUC1-based recombinant Bacillus Calmette-Guerin vaccines as candidates for breast cancer immunotherapy

IMPORTANCE OF THE FIELD

The challenge in breast cancer vaccine development is to find the best combination of antigen, adjuvant and delivery system to produce a strong and long-lasting immune response. Mucin 1 (MUC1) is a potential candidate target for breast cancer immunotherapy. Bacillus Calmette-Guerin (BCG) is used widely in human vaccines. Furthermore, it can potentially offer unique advantages for developing a safe and effective multi-vaccine vehicle. Due to these properties, the development of MUC1 based recombinant BCG (rBCG) vaccines for breast cancer immunotherapy has gained great momentum in recent years.

AREAS COVERED IN THIS REVIEW

Our aim is to discuss the recent progress in MUC1-based breast cancer immunotherapy and to highlight the advantages of MUC1-based rBCG vaccines as the new breast cancer vaccines.

WHAT THE READER WILL GAIN

Several promising MUC1-based rBCG vaccines have been shown to induce MUC1-specific antitumor immune responses in pre-clinical studies. This review updates and evaluates this very important and rapidly developing field, and provides a critical perspective and information source for its potential clinical applications.

TAKE HOME MESSAGE

MUC1-based rBCG vaccines have been shown to elicit an effective anti-tumor immune response in vivo demonstrating its potential utility in breast cancer treatment.

An essential epitope of anti-MUC1 monoclonal antibody KL-6 revealed by focused glycopeptide library

Human serum Krebs von den Lungen-6 (KL-6) antigen, a high-molecular-weight glycoprotein classified as a polymorphic epithelial mucin (MUC1), is a biomarker of diseases such as interstitial pneumonia, lung adenocarcinoma, breast cancer, colorectal adenocarcinoma, and hepatocellular carcinoma. Anti-KL-6 monoclonal antibody (anti-KL-6 MAb) is therefore a potential diagnostic and therapeutic reagent. Although glycosylation at Thr/Ser residues of the tandem-repeating MUC1 peptides appears to determine the disease-associated antigenic structures of KL-6, an essential epitope structure recognized by anti-KL-6 MAb remains unclear. In the present study, a novel compound library of synthetic MUC1 glycopeptides allowed the first rapid and precise evaluation of the specific epitope structure of anti-KL-6 MAb by combined use of a tailored glycopeptides library and common ELISA protocol. We demonstrated that the minimal antigenic structure, an essential epitope, recognized by anti-KL-6 MAb is a heptapeptide sequence Pro-Asp-Thr-Arg-Pro-Ala-Pro (PDTRPAP), in which the Thr residue is modified by Neu5Ac alpha2,3Gal beta1,3GalNAc alpha (2,3-sialyl T antigen, core 1-type O-glycan). Anti-KL-6 MAb did not bind with other tumor-relevant antigens, such as GalNAc alpha (Tn), Neu5Ac alpha2,6GalNAc alpha (STn), and Gal beta1,3GalNAc alpha (T), except for Neu5Ac alpha2,3Gal beta1,3(Neu5Ac alpha2,6)GalNAc alpha (2,3/2,6-disialyl T). However, anti-KL-6 MAb could not differentiate the above minimal antigenic glycopeptide from some core 2-based glycopeptides involving this crucial epitope structure and showed a similar binding affinity toward these compounds, indicating that branching at the O-6 position of GalNAc residue does not influence the interaction of anti-KL-6 MAb with some MUC1 glycoproteins involving an essential epitope. Actually, anti-KL-6 MAb reacts with 2,3/2,6-disialyl T having a 2,3-sialyl T component. This is why anti-KL-6 MAb often reacts with various kinds of tumor-derived MUC1 glycoproteins as well as a clinically important MUC1 glycoprotein biomarker of interstitial pneumonia, namely KL-6, originally discovered as a circulating pulmonary adenocarcinoma-associated antigen. In other words, combined use of anti-KL-6 MAb and some probes that can differentiate the sugars substituted at the O-6 position of the GalNAc residue in MUC1 glycopeptides including the PDTRPAP sequence might be a promising diagnostic protocol for individual disease-specific biomarkers. It was also revealed that glycosylation at neighboring Thr/Ser residues outside the immunodominant PDTRPAP motif strongly influences the interaction between anti-KL-6 MAb and MUC1 glycopeptides involving the identified epitope. Our novel strategy will greatly facilitate the processes for the identification of the tumor-specific and strong epitopes of various known anti-MUC1 MAbs and allow for their practical application in the generation of improved antibody immunotherapeutics, diagnostics, and MUC1-based cancer vaccines.

A potent, imaging adenoviral vector driven by the cancer-selective mucin-1 promoter that targets breast cancer metastasis

PURPOSE

With breast cancer, early detection and proper staging are critical, and will often influence both the treatment regimen and the therapeutic outcome for those affected with this disease. Improvements in these areas will play a profound role in reducing mortality from breast cancer.

EXPERIMENTAL DESIGN

In this work we developed a breast cancer-targeted serotype 5 adenoviral vector, utilizing the tumor-specific mucin-1 promoter in combination with the two-step transcriptional amplification system, a system used to augment the activity of weak tissue-specific promoters.

RESULTS

We showed the strong specificity of this tumor-selective adenovirus to express the luciferase optical imaging gene, leading to diagnostic signals that enabled detection of sentinel lymph node metastasis of breast cancer. Furthermore, we were able to target hepatic metastases following systemic administration of this mucin-1 selective virus.

CONCLUSIONS

Collectively, we showed that the amplified mucin-1 promoter-driven vector is able to deliver to and selectively express a desirable transgene in metastatic lesions of breast tumors. This work has strong clinical relevance to current diagnostic staging approaches, and could add to targeted therapeutic strategies to advance the fight against breast cancer.

Psychological intervention and health outcomes among women treated for breast cancer: a review of stress pathways and biological mediators

Breast cancer is a common cancer among American women. The diagnosis, treatment, and the challenges of survivorship all have potential to increase women's levels of distress to levels that might influence their adaptation and possibly the course of their disease. Psychological distress can influence tumor progression via many different pathways (e.g., genetic changes, immune surveillance, pro-angiogenic processes). Psychological intervention has been shown to facilitate psychological adaptation to breast cancer. But can psychological intervention influence cancer relevant biological outcomes among breast cancer survivors? We review the literature on how psychological intervention can influence cancer relevant biological outcomes among breast cancer patients. We limited the present review to randomized controlled trials reported in the past 6 years that tested the effects of psychological intervention on biological dependent variables among patients with non-metastatic breast cancer. There are data to suggest that psychological intervention can influence neuroendocrine (e.g., cortisol) and immune function indicators, especially lymphocyte proliferation and TH1 cytokine production. Future psychological intervention studies should also focus on more newly discovered stress-tumor pathways (e.g., neuroendocrine processes promoting tumor growth and metastasis) and follow larger cohorts of the more vulnerable patients over longer periods to evaluate the biobehavioral mechanisms and lasting effects of these interventions on health and quality of life.

Dendritic cells--why can they help and hurt us

Dendritic cells (DCs) show a Janus-like functional behavior. They help us by their orchestration of numerous immune responses to defend our body against invading pathogenic micro-organisms and also induce regulatory T cells to inhibit immune reactions against autoantigens as well as diverse harmless environmental antigens. However, DCs can also be of harm to us when misguided by their microenvironment as in allergic and autoimmune diseases or when DCs are targeted and exploited by microbes and cancer cells to evade the immune defense. This huge and diverse functional repertoire of DCs requires complex decision-making processes and the integration of multiple stimulatory and inhibitory signals. Although a given DC type has an extensive functionally plasticity, DCs are heterogeneous and individual DC subtypes are differentially distributed in tissues, express distinct sets of pattern recognition receptors and differ in their capacity to program naive T cells. With the help of transgenic mouse models and selective ablation of individual DC subtypes, we are just at the beginning of understanding the DC system in its complexity. Obtaining a more detailed knowledge of the DC system in mice and men holds strong promise for the successful induction of immunity and tolerance in therapeutic trials. This review presents the recent advances in the understanding of DC biology and discusses why and how DC can help and hurt us.

The anticancer immune response: indispensable for therapeutic success?

Although the impact of tumor immunology on the clinical management of most cancers is still negligible, there is increasing evidence that anticancer immune responses may contribute to the control of cancer after conventional chemotherapy. Thus, radiotherapy and some chemotherapeutic agents, in particular anthracyclines, can induce specific immune responses that result either in immunogenic cancer cell death or in immunostimulatory side effects. This anticancer immune response then helps to eliminate residual cancer cells (those that fail to be killed by chemotherapy) or maintains micrometastases in a stage of dormancy. Based on these premises, in this Review we address the question, How may it be possible to ameliorate conventional therapies by stimulating the anticancer immune response? Moreover, we discuss the rationale of clinical trials to evaluate and eventually increase the contribution of antitumor immune responses to the therapeutic management of neoplasia.