Risk Factors in Serrated Pathway Lesions: N-Glycosylation Profile as a Potential Biomarker of Progression to Malignancy.

Introduction: The serrated pathway contributes to interval colorectal cancers, highlighting the need for new biomarkers to assess lesion progression risk. The ß1,6-GlcNAc branched N-glycans expression in CRC cells was associated with an invasive phenotype and with immune evasion. Therefore, this study aims to identify potential risk factors for progression of serrated lesions (SLs) to malignancy, analyzing the N-glycosylation profile of epithelial/infiltrating immune cells. Methods: A retrospective cohort study was performed with data from 53 colonoscopies (48 patients). Sixty-three serrated pathway lesions (SPLs) were characterized based on N-glycosylation profile (lectin histochemistry/flow cytometry) and MGAT5 expression. Statistical analysis was performed to search for associations between the glycoprofile and clinical variables from each patient. Results: Increased ß1,6-GlcNAc branched N-glycans expression in epithelial cells is found associated with age (p = 0.007 in SPL), smoking (p = 0.038 in SL), increased BMI (p = 0.036 in sessile serrated lesions [SSL]), and polyp dimensions ≥10 mm (p = 0.001 in SL), while increased expression of these structures on immune cells is associated with synchronous CA number (CD4+T cells: p = 0.016; CD8+T cells: p = 0.044 in SL) and female gender (p = 0.026 in SL). Moreover, a lower high-mannose N-glycans expression in immune cells is associated with smoking (p = 0.010 in SPL) and synchronous CA presence (p = 0.010 in SPL). Higher expression of these glycans is associated with female (p = 0.016 in SL) and male (p = 0.044 in SL) gender, left colon location (p = 0.028), dysplasia (p = 0.028), and adenocarcinoma (p = 0.010). Conclusions: We identified an association between an abnormal glycoprofile and several clinical risk factors, proposing the N-glycosylation profile as a potential biomarker of tumor progression in the serrated pathway. The N-glycosylation anatomopathological profile analysis could be further used to decide shorter interval follow-up in patients with SPL.

Introdução: A via serreada contribui para os cancros colorretais de intervalo, destacando a necessidade de novos biomarcadores para determinar o risco de progressão destas lesões. A expressão de ß1,6-GlcNAc N-glicanos ramificados foi associada a um fenótipo invasivo e a evasão imune. Assim, este estudo tem como objetivo identificar potenciais fatores de risco de progressão das lesões serreadas para malignidade, analisando o perfil de N-glicosilação das células epiteliais/células imunitárias. Métodos: Foi realizado um estudo retrospetivo com dados de 53 colonoscopias (48 doentes). 63 lesões da via serreada foram caracterizadas segundo o perfil de N-glicosilação (histoquímica de lectinas/citometria de fluxo) e expressão de MGAT5. A análise estatística foi realizada para encontrar associações entre o perfil de N-glicosilação e as variáveis clínicas de cada doente. Resultados: O aumento da expressão de ß1,6-GlcNAc N-glicanos ramificados nas células epiteliais encontra-se associado com a idade (p = 0.007 nas SPL), tabagismo (p = 0.038 nas SL), aumento do BMI (p = 0.036 nas SSL), e pólipos com dimensões ≥10 mm (p = 0.001 nas SL), enquanto que o aumento destas estruturas nas células imunitárias está associado com o número de CA síncronos (células TCD4+: p = 0.016; células TCD8+: p = 0.044 nas SL) e o género feminino (p = 0.026 nas SL). Além disso, uma diminuição da expressão de N-glicanos ricos em manose está associada ao tabagismo (p = 0.010 para SPL) e a presença de adenomas síncronos (p = 0.010 nas SPL). A expressão aumentada destas estruturas está associado com o género feminino (p = 0.016 nas SSL), género masculino (p = 0.044 nas SSL), localização no cólon esquerdo (p = 0.028), displasia (p = 0­028) e adenocarcinoma (p = 0.010). Discussão/Conclusão: Identificámos uma associação entre um perfil de glicosilação anormal e vários fatores de risco clínicos, propondo o perfil de N-glicosilação como um potencial biomarcador de progressão tumoral na via serreada. A análise anatomopatológica do perfil de N-glicosilação pode vir a ser usada para decidir intervalos de follow-up mais curtos em doentes com SPL.

Glycans as shapers of tumour microenvironment: A sweet driver of T-cell-mediated anti-tumour immune response.

Essentially all cells are covered with a dense coat of different glycan structures/sugar chains, giving rise to the so-called glycocalyx. Changes in cellular glycosylation are a hallmark of cancer, affecting most of the pathophysiological processes associated with malignant transformation, including tumour immune responses. Glycans are chief macromolecules that define T-cell development, differentiation, fate, activation and signalling. Thus, the diversity of glycans expressed at the surface of T cells constitutes a fundamental molecular interface with the microenvironment by regulating the bilateral interactions between T-cells and cancer cells, fine-tuning the anti-tumour immune response. In this review, we will introduce the power of glycans as orchestrators of T-cell-mediated immune response in physiological conditions and in cancer. We discuss how glycans modulate the glyco-metabolic landscape in the tumour microenvironment, and whether glycans can synergize with immunotherapy as a way of rewiring T-cell effector functions against cancer cells.

Glycans as a key factor in self and nonself discrimination: impact on the breach of immune tolerance.

Glycans are carbohydrates that are made by all organisms and covalently conjugated to other biomolecules. Glycans cover the surface of both human cells and pathogens and are fundamental to defining the identity of a cell or an organism, thereby contributing to discriminating self from nonself. As such, glycans are a class of 'Self-Associated Molecular Patterns' that can fine-tune host inflammatory processes. In fact, glycans can be sensed and recognized by a variety of glycan-binding proteins (GBP) expressed by immune cells, such as galectins, siglecs, and C-type lectins, which recognize changes in the cellular glycosylation, instructing both pro-inflammatory and anti-inflammatory responses. In this review, we introduce glycans as cell-identification structures, discussing how glycans modulate host-pathogen interactions and how they can fine-tune inflammatory processes associated with infection, inflammation and autoimmunity. Finally, from the clinical standpoint, we discuss how glycoscience research can benefit life sciences and clinical medicine by providing a source of valuable biomarkers and therapeutic targets for immunity.

Bringing to Light the Risk of Colorectal Cancer in Inflammatory Bowel Disease: Mucosal Glycosylation as a Key Player.

Colitis-associated cancer is a major complication of inflammatory bowel disease remaining an important clinical challenge in terms of diagnosis, screening, and prognosis. Inflammation is a driving factor both in inflammatory bowel disease and cancer, but the mechanism underlying the transition from colon inflammation to cancer remains to be defined. Dysregulation of mucosal glycosylation has been described as a key regulatory mechanism associated both with colon inflammation and colorectal cancer development. In this review, we discuss the major molecular mechanisms of colitis-associated cancer pathogenesis, highlighting the role of glycans expressed at gut epithelial cells, at lamina propria T cells, and in serum proteins in the regulation of intestinal inflammation and its progression to colon cancer, further discussing its potential clinical and therapeutic applications.

Colitis-associated cancer (CAC) is a major complication of inflammatory bowel disease and the molecular mechanisms underlying CAC progression are still elusive. Protein glycosylation holds a great promise for improving the understanding of CAC immunopathogenesis, opening new avenues for clinical and therapeutic interventions.