New Insights into the Impact of Human Papillomavirus on Oral Cancer in Young Patients: Proteomic Approach Reveals a Novel Role for S100A8.

Human papillomavirus (HPV) infection has recently been linked to a subset of cancers affecting the oral cavity. However, the molecular mechanisms underlying HPV-driven oral squamous cell carcinoma (OSCC) onset and progression are poorly understood. METHODS: We performed MS-based proteomics profiling based on HPV status in OSCC in young patients, following biological characterization and cell assays to explore the proteome functional landscape. RESULTS: Thirty-nine proteins are differentially abundant between HPV (+) and HPV (-) OSCC. Among them, COPS3, DYHC1, and S100A8 are unfavorable for tumor recurrence and survival, in contrast to A2M and Serpine1, low levels of which show an association with better DFS. Remarkably, S100A8 is considered an independent prognostic factor for lower survival rates, and at high levels, it alters tumor-associated immune profiling, showing a lower proportion of M1 macrophages and dendritic cells. HPV (+) OSCC also displayed the pathogen-associated patterns receptor that, when activated, triggered the S100A8 and NFκB inflammatory responses. CONCLUSION: HPV (+) OSCC has a peculiar microenvironment pattern distinctive from HPV (-), involving the expression of pathogen-associated pattern receptors, S100A8 overexpression, and NFκB activation and responses, which has important consequences in prognosis and may guide therapeutic decisions.

Mutational Signatures Driven by Epigenetic Determinants Enable the Stratification of Patients with Gastric Cancer for Therapeutic Intervention.

DNA mismatch repair deficiency (dMMR) is associated with the microsatellite instability (MSI) phenotype and leads to increased mutation load, which in turn may impact anti-tumor immune responses and treatment effectiveness. Various mutational signatures directly linked to dMMR have been described for primary cancers. To investigate which mutational signatures are associated with prognosis in gastric cancer, we performed a de novo extraction of mutational signatures in a cohort of 787 patients. We detected three dMMR-related signatures, one of which clearly discriminates tumors with MLH1 gene silencing caused by promoter hypermethylation (area under the curve = 98%). We then demonstrated that samples with the highest exposure of this signature share features related to better prognosis, encompassing clinical and molecular aspects and altered immune infiltrate composition. Overall, the assessment of the prognostic value and of the impact of modifications in MMR-related genes on shaping specific dMMR mutational signatures provides evidence that classification based on mutational signature exposure enables prognosis stratification.

Targeting a cell surface vitamin D receptor on tumor-associated macrophages in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive tumor with limited treatment options and poor prognosis. We applied the in vivo phage display technology to isolate peptides homing to the immunosuppressive cellular microenvironment of TNBC as a strategy for non-malignant target discovery. We identified a cyclic peptide (CSSTRESAC) that specifically binds to a vitamin D receptor, protein disulfide-isomerase A3 (PDIA3) expressed on the cell surface of tumor-associated macrophages (TAM), and targets breast cancer in syngeneic TNBC, non-TNBC xenograft, and transgenic mouse models. Systemic administration of CSSTRESAC to TNBC-bearing mice shifted the cytokine profile toward an antitumor immune response and delayed tumor growth. Moreover, CSSTRESAC enabled ligand-directed theranostic delivery to tumors and a mathematical model confirmed our experimental findings. Finally, in silico analysis showed PDIA3-expressing TAM in TNBC patients. This work uncovers a functional interplay between a cell surface vitamin D receptor in TAM and antitumor immune response that could be therapeutically exploited.

Avaliação do microambiente tumoral em adenocarcinomas gástricos a partir de dados de expressão gênica / Evaluation of the tumor microenvironment in gastric adenocarcinomas using gene expression data

O câncer gástrico (CG) tem grande importância clínica devido a suas altas taxas de incidência e mortalidade estando entre os cinco tipos de câncer mais frequentes no mundo. O CG encontra-se associado ao diagnóstico tardio, que, somado a agressividade da doença, resulta em sobrevida mediana curta. A principal forma de tratamento é a cirurgia em conjunto com a quimioterapia. Mais recentemente, o tratamento com imunoterpia foi aprovado para casos de CG avançado metastático. O CG é usualmente classificado nos subtipos histológicos difuso e intestinal, porém, devido à sua alta heterogeneidade genética, pode ser também classificado em quatro subtipos moleculares (CIN, MSI, GS e EBV). Ambos aspectos de classificação estão associados a diferentes prognósticos e taxas de sobrevida, mas ainda não são suficientes para direcionar ou predizer quais pacientes respondem melhor a uma ou outra terapia. Neste contexto, outro fator relacionado à patogênese da doença, resposta a tratamento e prognóstico é o contexto imunológico do microambiente tumoral, como a composição e orientação funcional das células do infiltrado inflamatório associado ao tumor. Por meio de um método analítico de deconvolução aplicado a dados de expressão gênica é possível estimar a proporção de diferentes tipos celulares, além de seus aspectos funcionais. Neste trabalho, foi feito um levantamento das ferramentas e listas de genes marcadores de células imunes a fim de definir qual teria a melhor performance na estimação da proporção de células imunes em amostras de CG. Não observamos diferenças na composição do infiltrado inflamatório entre os subtipos histológios; já entre os subtipos moleculares de CG as proporções de linfóctios T CD8 se destacaram como maiores nos subtipos EBV e MSI, por exemplo. Foi então proposta uma classificação baseada em assinaturas mutacionais que conseguiu resgatar pacientes que apresentaram melhor prognóstico. O contexto imunológico nos pacientes com alta atividade mutacional (S4) apresentou elementos de que ser mais responsivo com maior expressão de genes associados à resposta imune citotóxica e do mecanismo de escape pelos checkpoints imunes. Além disso, há indícios de que há formação das estruturas terciárias de linfócitos pela correlação entre as quantidades estimadas de linfócitos T e B. Já o grupo com baixa atividade da assinatura (S4), associado a um pior prognóstico, apresentou maiores quantidades de linfócitos Treg. A avaliação global do microambiente tumoral, seus aspectos moleculares e imunológicos, proporciona dados mais informativos para estratificação dos pacientes quanto ao prognóstico e podem ser utilizadas em breve na prática clínica para direcionamento terapêutico.

Gastric cancer (GC) has great clinical importance due to its high incidence and mortality rates, being among the five most frequent types of cancer in the world. GC is associated with late diagnosis which, added to the aggressiveness of the disease, results in a short median survival. The main form of treatment is surgery in conjunction with chemotherapy. Recently, immunotherapy treatment has been approved for advanced metastatic GC. GC is usually classified into diffuse and intestinal histological subtypes, however, due to its high genetic heterogeneity, it can also be classified into four molecular subtypes (CIN, MSI, GS and EBV). Both classification are associated with different prognosis and survival rates, but they are still not sufficient to direct or predict which patients respond better to one or another therapy. In this context, another factor related to the pathogenesis of the disease, response to treatment and prognosis is the immunological context of the tumor microenvironment, such as the composition and functional orientation of the cells of the inflammatory infiltrate associated with the tumor. Through an analytical method of deconvolution applied to gene expression data, it is possible to estimate the proportion of different cell types, in addition to their functional aspects. In this work, the tools and lists of immune cell marker genes were surveyed in order to define which one would perform better in estimating the proportion of immune cells in GC samples. We did not observe differences in the composition of the inflammatory infiltrate between the histological subtypes; among the CG molecular subtypes, the proportions of T CD8 lymphocytes stood out as higher in the EBV and MSI subtypes, for example. A classification based on mutational signatures was then proposed, which managed to rescue patients with a better prognosis. The immunological context in these patients with high mutational activity (S4) showed elements of being more responsive with greater expression of genes associated with the cytotoxic immune response and the escape mechanism by immune checkpoints. In addition, there is evidence that there is formation of tertiary lymphocyte structures by the correlation between the estimated amounts of T and B lymphocytes. The group with low mutational signature activity (S4), on the other hand, associated with a worse prognosis, had higher amounts of Treg lymphocytes. The global assessment of the tumor microenvironment, its molecular and immunological aspects, provides more informative data for stratifying patients regarding prognosis and may soon be used in clinical practice for therapeutic guidance.