Study of extracellular vesicles from Squamous Cell Carcinoma in the modulation of the immune response of macrophages and dendritic cells and their communication with the tumor microenvironment

Abstract

Oral squamous cell carcinoma (OSCC) has a high incidence and mortality worldwide. The communication between tumor cells and the tumor microenvironment (TM) is essential for the cancer initiation and progression, and this communication can occur through extracellular vesicles (EVs). The TM is composed of several cell populations, including tumor-associated macrophages (TAMs) and dendritic cells (DCs). TAMs comprise different subtypes, with M2 being the most prevalent and associated with immune tolerance. DCs are recruited to the MT by tumor- and stroma-derived factors that can modulate these cells resulting in deficient DCs, which may acquire regulatory and immunosuppressive profile. However, the mechanisms involved in the modulation of immune cells during tumor development are still poorly understood, and among them, it is the role of EVs in cancer initiation and malignant transformation. Thus, the hypothesis of this study is that EVs obtained from potentially malignant lesions (oral leukoplakia, OL) modulate macrophages (M) and DCs, and their respective EVs, contributing to the maintenance of a tolerant environment and immune escape and, consequently, increasing permissiveness for SCC development. To answer this hypothesis, (1) EVs from OL and OSCC tissues, as well as keratinocytes and fibroblasts isolated from these tissues, will be characterized by nanoparticle tracking analysis (NTA) and subjected to macrophage polarization assays and DC activation from healthy patients and will be characterized by immunophenotyping and ELISA. (2) To investigate the effect of these EVs on Ms and DCs, EVs from immune cells will be characterized for number, size and shape by NTA, cryomicroscopy and transmission electron microscopy (TEM), and molecularly, by metabolomics, lipidomics and proteomics. (3) Then, EVs from Ms and DCs will be evaluated for their effect on lymphocyte proliferation and characterization of their subpopulations. (4) Finally, from the combination of the omics results, differential proteins will be selected for neutralization assays on EVs to analyze the reversion of lymphocyte phenotypes. Taken together, this study aims to reveal targets in EVs that are involved in promoting a tolerant microenvironment favoring the initiation and progression of oral squamous cell carcinoma. (AU)