Análise do papel dos exossomos derivados das linhagens celulares SCC-15 e HSC-3 no processo de angiogênese tumoral

Abstract

Exosome are extracellular microvesicles originated by inward budding of late endosomal membrane that represent an efficient form of intercellular communication. Because of its multiple biological functions, the focus of some recent studies has concentrated on the analysis of its role in cancer development, disease progression, invasion, angiogenesis and tumor metastasis formation. In this perspective, the present study aimed to characterize the secreted exosomes by two cell lines of oral squamous cell carcinomas (OSCC) (SCC-15 and HSC-3) and to evaluate its effects on a cell line of endothelial cells (HUVEC), in relation to their ability to form vascular structures, rates of migration, proliferation, and apoptosis / necrosis indices. Significantly higher means of cells with invasive (p<0.0001) and migratory potential (p = <0.0001) were observed for the HSC-3 cell line. Ultrastructurally, it was found that particles derived from the SCC-15 cell line exhibited a rounded morphology and diameter of less than 150 nm. No statistically significant difference was revealed between the studied cell lines, considering the nanovesicles quantization (p=0.2252) and exossomal size (p=0.1765). By indirect immunofluorescence, it was found that 22.15% of exosomes secreted by SCC-15 cells and 18.37% of exosomes derived from HSC-3 cells expressed anti-annexin antibody. With regard to the functional tests with HUVECs, treatment with exosomes derived from SCC-15 cell line induced a significant increase in their capacity of formation of vascular structures (p = <0.0001), migratory potential (p=0.0016) and rate of apoptosis (p<0.0001), while a decrease in cell proliferation was noted (p = 0.0030). On the other hand, the treatment with exosomes secreted by HSC-3 cell line produced a significant reduction in tubule formation (p<0.0001), motility (p = 0.0042) and cell proliferation (p=0.0010), whereas no statistically significant difference was observed in the apoptotic index (p=0.3004). The results of this study indicated the involvement of exosomes derived from OSCC cell lines in tumor angiogenesis process, in which the SCC-15 cells exhibited strong proangiogenic response and HSC-3 cell line showed antiangiogenic effect.