Therapeutic implications of immunogenic cell death in human cancer

Dendritic cells (DCs) are central to the adoptive immune response, and their function is regulated by diverse signals in a context-specific manner. Different DCs have been described in physiologic conditions, inflammation, and cancer, prompting a series of questions on how adoptive immune responses, or tolerance, develop against tumors. Increasing evidence suggests that tumor treatments induce a dramatic change on tumor-infiltrating lymphocytes and, in particular, on some DC subtypes. In this review, we summarize the latest evidence on the role of DCs in cancer and preliminary evidence on chemotherapy-associated antigens identified in human cancers

Immunogenicity comparison of interferon beta-1a preparations using the BALB/c mouse model: assessment of a new formulation for use in multiple sclerosis

The in vivo immunogenicity of a new interferon (IFN) beta-1a product (Rebif New Formulation; RNF) was compared with that of two approved recombinant human IFN beta-1a products (Rebif and Avonex). Immunogenic potential was assessed based on time to development of neutralizing antibodies (NAbs) and NAb titer. Female BALB/c mice (six in each group) received RNF, Rebif or Avonex (1.0 microg/mL subcutaneously three times weekly), and serum samples collected on Days 7, 21, and 35 (Study 1), or 28, 42, 49, and 60 (Study 2) were assayed for NAbs. In Study 1, no mice had NAbs at Day 7, but by Day 21 one mouse in the RNF group had NAbs, compared with three and four mice in the Rebif and Avonex groups, respectively. Results were similar in Study 2. All control mice were NAb negative; all actively treated mice had NAbs by day 35 or 42. Throughout Study 1, NAb titers were lowest in the RNF group and highest in the Avonex group, and at day 35, NAb titers were significantly lower in the RNF group than the Rebif group (p = 0.037). Results indicate that, on a gram-for-gram basis, RNF appears less immunogenic than Rebif or Avonex

Wnt3a neutralization enhances T-cell responses through indirect mechanisms and restrains tumor growth

The Wnt/beta-catenin pathway regulates T-cell functions, including the repression of effector functions to the advantage of memory development via Tcf1. In a companion study, we demonstrate that, in human cancers, Wnt3a/beta-catenin signaling maintains tumor-infiltrating T cells in a partially exhausted status. Here, we have investigated the effects of Wnt3a neutralization in vivo in a mouse tumor model. Abundant Wnt3a was released, mostly by stromal cells, in the tumor microenvironment. We tested whether Wnt3a neutralization in vivo could rescue the effector capacity of tumor-infiltrating T cells, by administering an antibody to Wnt3a to tumor-bearing mice. This therapy restrained tumor growth and favored the expansion of tumor antigen-specific CD8(+) effector memory T cells with increased expression of Tbet and IFN gamma and reduced expression of Tcf1. However, the effect was not attributable to the interruption of T-cell-intrinsic beta-catenin signaling, because Wnt3a/beta-catenin activation correlated with enhanced, not reduced, T-cell effector functions both ex vivo and in vitro. Adoptively transferred CD8(+) T cells, not directly exposed to the anti-Wnt3a antibody but infiltrating previously Wnt3a-neutralized tumors, also showed improved functions. The rescue of T-cell response was thus secondary to T-cell-extrinsic changes that likely involved dendritic cells. Indeed, tumor-derived Wnt3a strongly suppressed dendritic cell maturation in vitro, and anti-Wnt3a treatment rescued dendritic cell activities in vivo. Our results clarify the function of the Wnt3a/beta-catenin pathway in antitumor effector T cells and suggest that Wnt3a neutralization might be a promising immunotherapy for rescuing dendritic cell activities. (C) 2018 AACR

CD8+ T cells specific for cryptic apoptosis-associated epitopes exacerbate experimental autoimmune encephalomyelitis

The autoimmune immunopathology occurring in multiple sclerosis (MS) is sustained by myelin-specific and -nonspecific CD8(+) T cells. We have previously shown that, in MS, activated T cells undergoing apoptosis induce a CD8(+) T cell response directed against antigens that are unveiled during the apoptotic process, namely caspase-cleaved structural proteins such as non-muscle myosin and vimentin. Here, we have explored in vivo the development and the function of the immune responses to cryptic apoptosis-associated epitopes (AEs) in a well-established mouse model of MS, experimental autoimmune encephalomyelitis (EAE), through a combination of immunization approaches, multiparametric flow cytometry, and functional assays. First, we confirmed that this model recapitulated the main findings observed in MS patients, namely that apoptotic T cells and effector/memory AE-specific CD8(+) T cells accumulate in the central nervous system of mice with EAE, positively correlating with disease severity. Interestingly, we found that AE-specific CD8(+) T cells were present also in the lymphoid organs of unprimed mice, proliferated under peptide stimulation in vitro, but failed to respond to peptide immunization in vivo, suggesting a physiological control of this response. However, when mice were immunized with AEs along with EAE induction, AE-specific CD8(+) T cells with an effector/memory phenotype accumulated in the central nervous system, and the disease severity was exacerbated. In conclusion, we demonstrate that AE-specific autoimmunity may contribute to immunopathology in neuroinflammation

Effects of 5-fluorouracil on morphology, cell cycle, proliferation, apoptosis, autophagy and ros production in endothelial cells and cardiomyocytes

Antimetabolites are a class of effective anticancer drugs interfering in essential biochemical processes. 5-Fluorouracil (5-FU) and its prodrug Capecitabine are widely used in the treatment of several solid tumors (gastro-intestinal, gynecological, head and neck, breast carcinomas). Therapy with fluoropyrimidines is associated with a wide range of adverse effects, including diarrhea, dehydration, abdominal pain, nausea, stomatitis, and hand-foot syndrome. Among the 5-FU side effects, increasing attention is given to cardiovascular toxicities induced at different levels and intensities. Since the mechanisms related to 5-FU-induced cardiotoxicity are still unclear, we examined the effects of 5-FU on primary cell cultures of human cardiomyocytes and endothelial cells, which represent two key components of the cardiovascular system. We analyzed at the cellular and molecular level 5-FU effects on cell proliferation, cell cycle, survival and induction of apoptosis, in an experimental cardioncology approach. We observed autophagic features at the ultrastructural and molecular levels, in particular in 5-FU exposed cardiomyocytes. Reactive oxygen species (ROS) elevation characterized the endothelial response. These responses were prevented by a ROS scavenger. We found induction of a senescent phenotype on both cell types treated with 5-FU. In vivo, in a xenograft model of colon cancer, we showed that 5-FU treatment induced ultrastructural changes in the endothelium of various organs. Taken together, our data suggest that 5-FU can affect, both at the cellular and molecular levels, two key cell types of the cardiovascular system, potentially explaining some manifestations of 5-FU-induced cardiovascular toxicity

Discovery of chemotherapy-associated ovarian cancer antigens by interrogating memory T cells

According to the immunogenic cell death hypothesis, clinical chemotherapy treatments may result in CD8(+) and CD4(+) T-cell responses against tumor cells. To discover chemotherapy-associated antigens (CAAs), T cells derived from ovarian cancer (OC) patients (who had been treated with appropriate chemotherapy protocols) were interrogated with proteins isolated from primary OC cells. We screened for immunogenicity using two-dimensional electrophoresis gel-eluted OC proteins. Only the selected immunogenic antigens were molecularly characterized by mass-spectrometry-based analysis. Memory T cells that recognized antigens associated with apoptotic (but not live) OC cells were correlated with prolonged survival in response to chemotherapy, supporting the model of chemotherapy-induced apoptosis as an adjuvant of anti-tumor immunity. The strength of both memory CD4(+) and CD8(+) T cells producing either IFN- or IL-17 in response to apoptotic OC antigens was also significantly greater in Responders to chemotherapy than in nonresponders. Immunogenicity of some of these antigens was confirmed using recombinant proteins in an independent set of patients. The T-cell interrogation system represents a strategy of reverse tumor immunology that proposes to identify CAAs, which may then be validated as possible prognostic tumor biomarkers or cancer vaccines

Polyphenol-mediated autophagy in cancer: Evidence of in vitro and in vivo studies

One of the hallmarks of cellular transformation is the altered mechanism of cell death. There are three main types of cell death, characterized by different morphological and biochemical features, namely apoptosis (type I), autophagic cell death (type II) and necrosis (type III). Autophagy, or self-eating, is a tightly regulated process involved in stress responses, and it is a lysosomal degradation process. The role of autophagy in cancer is controversial and has been associated with both the induction and the inhibition of tumor growth. Autophagy can exert tumor suppression through the degradation of oncogenic proteins, suppression of inflammation, chronic tissue damage and ultimately by preventing mutations and genetic instability. On the other hand, tumor cells activate autophagy for survival in cellular stress conditions. Thus, autophagy modulation could represent a promising therapeutic strategy for cancer. Several studies have shown that polyphenols, natural compounds found in foods and beverages of plant origin, can efficiently modulate autophagy in several types of cancer. In this review, we summarize the current knowledge on the effects of polyphenols on autophagy, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of polyphenols for envisioning future therapies employing polyphenols as chemoadjuvants

Polyphenol-Mediated Autophagy in Cancer: Evidence of In Vitro and In Vivo Studies.

One of the hallmarks of cellular transformation is the altered mechanism of cell death. There are three main types of cell death, characterized by different morphological and biochemical features, namely apoptosis (type I), autophagic cell death (type II) and necrosis (type III). Autophagy, or self-eating, is a tightly regulated process involved in stress responses, and it is a lysosomal degradation process. The role of autophagy in cancer is controversial and has been associated with both the induction and the inhibition of tumor growth. Autophagy can exert tumor suppression through the degradation of oncogenic proteins, suppression of inflammation, chronic tissue damage and ultimately by preventing mutations and genetic instability. On the other hand, tumor cells activate autophagy for survival in cellular stress conditions. Thus, autophagy modulation could represent a promising therapeutic strategy for cancer. Several studies have shown that polyphenols, natural compounds found in foods and beverages of plant origin, can efficiently modulate autophagy in several types of cancer. In this review, we summarize the current knowledge on the effects of polyphenols on autophagy, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of polyphenols for envisioning future therapies employing polyphenols as chemoadjuvants

IL-18 receptor marks functional CD8+ T cells in non-small cell lung cancer

IL-18 is an inflammasome-related cytokine, member of the IL-1 family, produced by a wide range of cells in response to signals by several pathogen-or damage-associated molecular patterns. It can be highly represented in tumor patients, but its relevance in human cancer development is not clear. In this study, we provide evidence that IL-18 is principally expressed in tumor cells and, in concert with other conventional Th1 cell-driven cytokines, has a pivotal role in establishing a pro-inflammatory milieu in the tumor microenvironment of human non-small cell lung cancer (NSCLC). Interestingly, the analysis of tumor-infiltrating CD8(+) T cell populations showed that (i) the relative IL-18 receptor (IL-18R) is significantly more expressed by the minority of cells with a functional phenotype (T-bet(+)Eomes(+)), than by the majority of those with the dysfunctional phenotype T-bet(+)Eomes(+) generally resident within tumors; (ii) as a consequence, the former are significantly more responsive than the latter to IL-18 stimulus in terms of IFN gamma production ex vivo; (iii) PD-1 expression does not discriminate these two populations. These data indicate that IL-18R may represent a biomarker of the minority of functional tumor-infiltrating CD8(+) T cells in adenocarcinoma NSCLC patients. In addition, our results lead to envisage the possible therapeutic usage of IL-18 in NSCLC, even in combination with other checkpoint inhibitor approaches