Tertiary Lymphoid Tissue in Colorectal Cancer: A Key Player in the Tumour Immune Microenvironment

Tumour infiltrating lymphocytes influence colorectal cancer (CRC) progression. However, lymphocyte infiltration comes in different flavours and evidence has been provided that the spatial distribution of immune cells within the tumour tissue is an important immunological feature. The aim of this thesis was to investigate how the dual localization of tumour infiltrating lymphocytes (TILs) can affect their function in the tumour microenvironment. The project started with the analysis of the CD3 compartment, as CD3+ T cell infiltration (CD3-TILs) is a recognized positive prognostic factor for CRC patients. Results here presented show that CD3+ tumour-infiltrating lymphocytes are present both interspersed in the tumour tissue or scattered throughout the stroma (CD3-TILs) and also aggregated in lymphoid structures showing features of tertiary lymphoid tissue (CD3-TLT). Tumour-associated TLT had a peculiar compartmentalization, with CD3+ T cells and CD20+ B lymphocytes holding complementary positions and with distinct types of dendritic cell populations among them. The presence of HEVs (High Endothelial Venules) suggests a role for TLT in T cell recruitment at the tumour site. To test this hypothesis in human cancer, I performed a whole tissue analysis of the CD3+ infiltrate on CRC sections and found a positive correlation between CD3-TIL and CD3-TLT densities. I further confirmed the hypothesis in vivo in a murine model of colitis-associated cancer (AOM/DSS). AOM/DSS treated mice had expanded TLT compared to control mice. Intravenously injected GFP+ splenocytes localised in TLT of tumour-bearing mice more than in control mice. I then investigated the clinical significance of CD3-TLT in relationship with CD3-TILs in a cohort of 351 CRC patients. In patients with node-negative (without lymph node metastasis, stage II) CRC, a high density of CD3-TLT and CD3-TILs associated to a better prognosis, while in patients with node-positive (presence of lymph node metastasis, stage III) CRC, TLT and TIL density were irrelevant in predicting patient prognosis, thus behaving as biomarkers only for early stage CRC patients. In the second part of my thesis, I analysed the distribution of B cells in colorectal cancer and their possible contribution to disease progression. Despite still controversial, increasing evidence that B cells play a role in cancer progression has been provided, bringing up the hypothesis that also B-cell responses should be considered as targets of immunotherapeutic approaches. Similarly to CD3+ cells, I showed that, both in human and in preclinical models of CRC, B cells display a dual geographical distribution, either within tertiary lymphoid tissue (CD20-TLT) or dispersed at the tumour invasive margin (CD20-TILs). Therefore, I evaluated the role of B cells according to their localization in the microenvironment. I found that CD20-TLT associated to better prognosis, while CD20-TILs did not. Interestingly, CD20-TLT correlated with CD20-TILs only among patients who experienced cancer recurrence. This result suggests that, when located within a lymphoid site, B cells might have a protective anti-tumour function, participating in an antitumour immune response. Conversely, the distribution of B cells scattered in the microenvironment is likely to reflect a non-specific pro-tumour inflammatory reaction. To confirm the hypothesis in vivo and attempt to dissect the dual function of B cells, I took advantage of two CRC preclinical models in which B cells present a distinct geographical distribution in the tumour microenvironment. In the first model, B cells mainly localise within TLT, while in the second one B cells diffusely infiltrate the mucosa, without forming aggregates. I found that in a model in which B cells localize primarily within TLT, the genetic deficiency of B cells significantly increased tumour formation, suggesting that B cells within TLT might exert an important anti-tumour function. In contrast, in a model in which B cells only localize within the tissue, genetic deficiency of B cells reduces tumour growth, suggesting that infiltrating B-TILs might have a pro-tumour role. Therefore, the occurrence of TLT is associated with lymphocyte infiltration in CRC, contributing to recruitment of CD3-TILs. TLT and TILs work together to set up an anti-tumour immune response in patients with low-risk early-stage colorectal cancer. Thus, TLT represents a novel prognostic biomarker for CRC. As to the B cell compartment, their differential distribution in the tumour site corresponds to distinct prognostic functions. This evidence suggests that the design of novel immunotherapeutic drugs depleting B cells should take into account their ability to selectively targeting CD20-TILs but not C20-TLT

Functional TRAIL receptors in monocytes and tumor-associated macrophages: A possible targeting pathway in the tumor microenvironment

Despite the accepted dogma that TRAIL kills only tumor cells and spares normal ones, we show in this study that mononuclear phagocytes are susceptible to recombinant TRAIL via caspase-dependent apoptosis. Human resting monocytes and in vitro-differentiated macrophages expressed substantial levels of the functional TRAIL receptors (TRAIL-R1 and TRAIL-R2), while neutrophils and lymphocytes mostly expressed the non-signaling decoy receptor (TRAIL-R3). Accordingly, exclusively monocytes and macrophages activated caspase-8 and underwent apoptosis upon recombinant TRAIL treatment. TRAIL-Rs were up-regulated by anti-inflammatory agents (IL-10, glucocorticoids) and by natural compounds (Apigenin, Quercetin, Palmitate) and their treatment resulted in increased TRAIL-induced apoptosis. In mice, the only signaling TRAIL-R (DR5) was preferentially expressed by blood monocytes rather than neutrophils or lymphocytes. In both mice and humans, Tumor-Associated Macrophages (TAM) expressed functional TRAIL-R, while resident macrophages in normal tissues did not. As a proof of principle, we treated mice bearing a murine TRAIL-resistant fibrosarcoma with recombinant TRAIL. We observed significant decrease of circulating monocytes and infiltrating TAM, as well as reduced tumor growth and lower metastasis formation. Overall, these findings demonstrate that human and murine monocytes/macrophages are, among leukocytes, uniquely susceptible to TRAIL-mediated killing. This differential susceptibility to TRAIL could be exploited to selectively target macrophages in tumors

Tertiary Lymphoid Structures in Cancer: Drivers of Antitumor immunity, immunosuppression, or Bystander Sentinels in Disease?

Secondary lymphoid organs are integral to initiation and execution of adaptive immune responses. These organs provide a setting for interactions between antigen-specific lymphocytes and antigen-presenting cells recruited from local infected or inflamed tissues. Secondary lymphoid organs develop as a part of a genetically preprogrammed process during embryogenesis. However, organogenesis of secondary lymphoid tissues can also be recapitulated in adulthood during de novo lymphoid neogenesis of tertiary lymphoid structures (TLSs). These ectopic lymphoid-like structures form in the inflamed tissues afflicted by various pathological conditions, including cancer, autoimmunity, infection, or allograft rejection. Studies are beginning to shed light on the function of such structures in different disease settings, raising important questions regarding their contribution to progression or resolution of disease. Data show an association between the tumor-associated TLSs and a favorable prognosis in various types of human cancer, attracting the speculation that TLSs support effective local antitumor immune responses. However, definitive evidence for the role for TLSs in fostering immune responses in vivo are lacking, with current data remaining largely correlative by nature. In fact, some more recent studies have even demonstrated an immunosuppressive, tumor-promoting role for cancer-associated TLSs. In this review, we will discuss what is known about the development of cancer-associated TLSs and the current understanding of their potential role in the antitumor immune response

Tertiary Lymphoid Structures:Autoimmunity Goes Local

Tertiary lymphoid structures (TLS) are frequently observed in target organs of autoimmune diseases. TLS present features of secondary lymphoid organs such as segregated T and B cell zones, presence of follicular dendritic cell networks, high endothelial venules and specialized lymphoid fibroblasts and display the mechanisms to support local adaptive immune responses toward locally displayed antigens. TLS detection in the tissue is often associated with poor prognosis of disease, auto-antibody production and malignancy development. This review focuses on the contribution of TLS toward the persistence of the inflammatory drive, the survival of autoreactive lymphocyte clones and post-translational modifications, responsible for the pathogenicity of locally formed autoantibodies, during autoimmune disease development

Comunicação/educação na formação profissional

O trabalho propõe a articulação da Comunicação e da Educação como um campo problemático, tratando de identificar algumas das questões que o caracterizam com vistas a contribuir para a sua construção teórica. Considerar que não se conseguiu transcender a perspectiva da análise de experiências, o que limita a reflexão e a incorporação destas temáticas no âmbito acadêmico com o status teórico que lhe corresponde. Isto, por sua vez, dificulta sua definição como conteúdos com vistas à formação tanto de comunicadores como de educadores. Respondendo a esta questão, o trabalho procura identificar alguns dos eixos que poderiam considerar-se fundamentais com o objetivo de incorporação dessas temáticas nos âmbitos de formação e ressignificação no contexto da sociedade midiática, com o impacto das novas tecnologias da comunicação e da informação, na cultura e nos modos de conhecer.The work proposes the articulation of Communication and Education as a problematic field, in an attempt to identify a few matters that characterize it aiming at contributing to its theoretical construction. It considers that it was not possible to transcend the perspective of experience analysis, something that limits the reflection on and incorporation of these themes in the academic realm with the theoretical status corresponding to it. This, on the other hand, makes it difficult to make definitions in the form of content aiming at educating both communicators as well as educators. Approaching this question, the work tries to identify a few axles that may be considered as fundamental, aiming at incorporating these themes in the education and reinterpretation ambits in the context of the mediatic society, with the impact of the new communication and information technologies, on culture and on the modes of knowledge

Tertiary Intratumor Lymphoid Tissue in Colo-Rectal Cancer

Ectopic (or tertiary) lymphoid tissue develops at sites of inflammation or infection in non lymphoid organs and is associated with chronic inflammation. In colon mucosa, small lymphoid aggregates are already present in homeostatic conditions, as part of the gut-associated lymphoid tissue and play an essential role in the immune response to perturbations of the mucosal microenvironment. Despite the recognized role of inflammation in tumor progression, the presence and biological function of lymphoid tissue in cancer has been poorly investigated. We identified aggregates of lymphocytes resembling tertiary lymphoid tissue in human colorectal cancer specimens; intratumor accumulations of lymphocytes display a high degree of compartmentalization, with B and T cells, mature dendritic cells and a network of CD21+ follicular dendritic cells (FDC). We analyzed the adaptation of colon lymphoid tissue in a murine model of colitis-associated cancer (AOM/DSS). B cell follicle formation increases in the context of the chronic inflammation associated to intestinal neoplasia, in this model. A network of lymphatic and haematic vessels surrounding B cell follicles is present and includes high endothelial venules (HEV). Future task is to determine whether lymphoid tissue contributes to the persistence of the tumor-associated inflammatory reaction, rather than represent a functional immune compartment, potentially participating to the anti tumor response

Tertiary intratumor lymphoid tissue in colo-rectal cancer

Ectopic (or tertiary) lymphoid tissue develops at sites of inflammation or infection in non lymphoid organs and is associated with chronic inflammation. In colon mucosa, small lymphoid aggregates are already present in homeostatic conditions, as part of the gut-associated lymphoid tissue and play an essential role in the immune response to perturbations of the mucosal microenvironment. Despite the recognized role of inflammation in tumor progression, the presence and biological function of lymphoid tissue in cancer has been poorly investigated. We identified aggregates of lymphocytes resembling tertiary lymphoid tissue in human colorectal cancer specimens; intratumor accumulations of lymphocytes display a high degree of compartmentalization, with B and T cells, mature dendritic cells and a network of CD21 + follicular dendritic cells (FDC). We analyzed the adaptation of colon lymphoid tissue in a murine model of colitis-associated cancer (AOM/DSS). B cell follicle formation increases in the context of the chronic inflammation associated to intestinal neoplasia, in this model. A network of lymphatic and haematic vessels surrounding B cell follicles is present and includes high endothelial venules (HEV). Future task is to determine whether lymphoid tissue contributes to the persistence of the tumor-associated inflammatory reaction, rather than represent a functional immune compartment, potentially participating to the anti tumor response. © 2012 by the authors; licensee MDPI, Basel, Switzerland

Could Celiac Disease and Overweight/Obesity Coexist in School-Aged Children and Adolescents? A Systematic Review

: Background: Celiac disease (CD) is a multifactorial, immune-mediated enteropathic disorder that may occur at any age with heterogeneous clinical presentation. In the last years, unusual manifestations have become very frequent, and currently, it is not so uncommon to diagnose CD in subjects with overweight or obesity, especially in adults; however, little is known in the pediatric population. This systematic review aims to evaluate the literature regarding the association between CD and overweight/obesity in school-age children. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. An electronic database search of articles published in the last 20 years in English was carried out in Web of Sciences, PubMed, and Medline. The quality of the included studies was assessed by using the STrengthening the Reporting of OBservational studies in Epidemiology statement. Results: Of the 1396 articles identified, 9 articles, investigating overweight/obesity in children/adolescents affected by CD or screening CD in children/adolescents with overweight/obesity, met the inclusion criteria. Overall, the results showed that the prevalence of overweight or obesity in school-age children (6-17 years) affected by CD ranged between 3.5% and 20%, highlighting that the coexistence of CD with overweight/obesity in children is not uncommon as previously thought. Conclusion: Although CD has been historically correlated with being underweight due to malabsorption, it should be evaluated also in children with overweight and obesity, especially those who have a familiar predisposition to other autoimmune diseases and/or manifest unusual symptoms of CD

Immune-based therapies in pancreatic and colorectal cancers and biomarkers of responsiveness

Immune-based strategies are the most promising treatments to improve cancer disease control. Early clinical trials are ongoing to test the safety and feasibility of immune-based therapies for gastrointestinal cancers. However, to date, immunotherapy has been only an experimental option for these diseases and a better understanding of their molecular, cellular, structural and clinical dissimilarities is crucial in the generation of tailored immunotherapeutic treatments. In this review, we will summarize the key mechanisms that regulate the action of immune system in cancer and the different immune-based approaches aimed at improving disease control in patients with advanced disease. We will then move on to discussing the current immunotherapeutic approaches in two types of gastrointestinal (colo-rectal and pancreatic) cancers, whose immune microenvironment has been lately object of intense analyses and has emerged as an important determinant of clinical outcome