Vimentin expression and the influence of Matrigel in cell lines of head and neck squamous cell carcinoma.

Vimentin is a cytoeskeletal intermediate filament protein commonly observed in mesenchymal cells; however, it can also be found in malignant epithelial cells. It is demonstrated in several carcinomas, such as those of the cervix, breast and bladder, in which it is widely used as a marker of the epithelial to mesenchymal transition that takes place during embryogenesis and metastasis. Vimentin is associated with tumors that show a high degree of invasiveness, being detected in invasion front cells. Its expression seems to be influenced by the tumor microenvironment. The aim of this study was to evaluate vimentin expression in head and neck squamous cell carcinoma (HNSCC) cell lines, and to investigate the contribution of the microenvironment to its expression. HNSCC cell lines (HN6, HN30 and HN31) and an immortalized nontumorigenic cell line (HaCaT) were submitted to a three-dimensional assay with Matrigel. Cytoplasmatic staining of the HN6 cell line cultured without Matrigel and of the HN30 and HN31 cell lines cultured with Matrigel was demonstrated through immunohistochemistry. Western Blotting revealed a significant decrease in vimentin expression for the HN6 cell line and a significant increase for the HN30 and HN31 cell lines cultured with Matrigel. The results suggest that vimentin can be expressed in HNSCC cells and its presence is influenced by the microenvironment of a tumor.

Análise da expressão das proteínas ß-catenina e caderina-E em linhagens celulares de carcinoma epidermoide de cabeça e pescoço / Analysis of ß-catenin and E-cadherin protein expression in head and neck squamous cell carcinoma cell lines

O carcinoma epidermoide corresponde a 95% das neoplasias malignas da cavidade oral, sendo seu mecanismo de invasão pouco conhecido. As células dessa neoplasia sofrem alterações genéticas e epigenéticas que as deixam com um caráter mais agressivo e, consequentemente, invasivo. Algumas vias de sinalizaçãoexercem papel importante sobre essas alterações. entre elas, a via do Wnt, em que se encontra um complexo formado por ß-catenina, um proto-oncogene e caderina-E, uma das principais moléculas de adesão do epitélio. Esse complexo torna-se responsável pela adesão entre as células e também por controlar a diferenciação morfológica e a proliferação celular. Assim, o propósito deste estudo foi analisar a expressão das proteínas ß-catenina e caderina-E em linhagens celulares derivadas de carcinoma epidermoide de cabeça e pescoço (CECP) e verificar a influência da matriz extracelular na expressão dessas proteínas. Os resultados mostraram que houve variação na expressão de ß-catenina e de caderina-E, dependendo da linhagem estudada, bem como do ambiente de cultivo celular empregado. Portanto, as proteínas ß-catenina e caderina-E foram expressas no CECP e a matriz extracelular foi capaz de alterar a expressão dessas proteínas

Different expression patterns of pAkt, NF-κB and cyclin D1 proteins during the invasion process of head and neck squamous cell carcinoma: an in vitro approach.

BACKGROUND: Several signaling pathways are involved in the progression of squamous cell carcinoma. Among them, activated PI3K/Akt may result in NF-κB nuclear translocation, thus leading to the transcription of genes enrolled in cellular invasion and proliferation, such as cyclin D1. This study sought to evaluate the expression of pAkt, NF-κB and cyclin D1 proteins in head and neck squamous cell carcinoma cell lines and their respective in vitro-obtained invasive clones. METHODS: Squamous cell carcinoma cell lines originating from the tongue, pharynx and the metastatic lymph node were submitted to an in vitro invasion assay to select invasive clones. All experimental groups were submitted to immunofluorescence and Western blot assays. Statistical analysis was performed through a Student's t-test with a significance level of 5%. RESULTS: The pAkt and NF-κB expression differed from cytoplasm and nucleus depending on the studied cell line. The invasive clone from the tongue presented a network-like structure of pAkt's cytoplasmic expression. This lineage as well as the invasive clone from pharynx also showed pAkt and NF-κB nuclear transportation. Significant pAkt and NF-κB increases were observed in the tongue and pharynx invasive clones. Cyclin D1 was detected in the nucleus of all studied cells and was significantly enhanced in the invasive clones from tongue and pharynx. CONCLUSION: This study suggests the participation of pAkt, NF-κB and cyclin D1 in the invasion process of head and neck squamous cell carcinoma. Moreover, cytoplasmic pAkt network-like structure was probably related to cytoskeleton changes presented during invasion.