Characterization of extracellular vesicles secreted by cancer cells and evaluation of their role in the progression, metastasis and prognosis of head and neck squamous cell carcinoma

Abstract

The head and neck squamous cell carcinoma (HNSCC) is an epithelial malignant tumor that shows its highest incidence in the upper aerodigestive tract, being considered one of the six most common malignancies worldwide. Several studies have focused on the establishment of biomarkers for early diagnosis and improvement of the prognosis of this cancer, mainly because of HNSCC's high rates of morbidity and mortality. Among the processes involved in carcinogenesis, local invasion and subsequent metastasis are the most relevant clinically, although they are the least understood events at the molecular level. In this way, the determination of biomarkers involved in the progression of HNSCC is very important since it may dictate the prognosis of the tumor, indicate its best treatment or even introduce new therapies. Recent evidences have shown that metastasis can be the result of extracellular vesicles release from tumor cells to the blood or lymphatic system. Actually, several cell types and lineages may secrete vesicles during physiological conditions, but when released by tumor cells, extracellular vesicles can participate in the formation of pre-metastatic niches. Thus, the identification of vesicles derived from HNSCC cells will enhance and facilitate the process of early diagnosis and may provide important information related to tumor progression, and especially to the development of metastasis, what could improve the treatment response or even help in the development of new chemotherapeutic agents. Therefore, this study aims to identify and characterize in vitro vesicles secreted by HNSCC cell lines. Furthermore, It will evaluated the presence of extracellular vesicles in the blood of patients diagnosed with HNSCC in order to find the relationship with the tumor biological behavior. Two potential candidates to evaluate in extracellular vesicles are the prion protein (PrPC) and its ligand STI1, both were recently described by our group as being secreted in extracellular vesicles and by tumor cells. (AU)