RESUMEN
BACKGROUND: Toll-like receptor 9 (TLR9) is a cellular receptor, which recognizes bacterial and host-derived DNA. Stimulation of TLR9 induces cellular invasion via matrix metalloproteinase 13 (MMP-13). The aim of this study was to evaluate the role of TLR9 in invasion of oral tongue squamous cell carcinoma (OTSCC). METHODS: The effects of TLR9 ligands on oral squamous cell carcinoma cell lines were studied with invasion and migration assays, as well as in a myoma organotypic model. RESULTS: The TLR9 ligand, CpG-ODN, increased invasion and migration in OTSCC lines. These effects were reduced by TLR9 siRNA or inhibition with TLR9 antibodies. Immunohistochemical analysis of tissues from 195 patients with OTSCC revealed that TLR9 was expressed in 181/195 carcinomas. The expression of TLR9 was higher in the malignant cells than in the normal epithelium. High TLR9 expression was associated with high MMP-13 expression and poor differentiation. High TLR9 expression was also identified as an independent predictor of poor prognosis (HR 1.810, 95% CI [1.053-3.112]). CONCLUSION: Toll-like receptor 9 mediates OTSCC invasion and migration in vitro and is an independent prognostic factor of OTSCC. Inhibition of TLR9 may be a novel therapeutic opportunity in oral cancer.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/patología , Receptor Toll-Like 9/biosíntesis , Neoplasias de la Lengua/metabolismo , Neoplasias de la Lengua/patología , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/biosíntesis , Diferenciación Celular/fisiología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Movimiento Celular/fisiología , Femenino , Humanos , Inmunohistoquímica , Masculino , Metaloproteinasa 13 de la Matriz/biosíntesis , Metaloproteinasa 13 de la Matriz/metabolismo , Persona de Mediana Edad , Invasividad Neoplásica , Oligodesoxirribonucleótidos/farmacología , Pronóstico , ARN Interferente Pequeño/administración & dosificación , ARN Interferente Pequeño/genética , Carcinoma de Células Escamosas de Cabeza y Cuello , Receptor Toll-Like 9/genéticaRESUMEN
BACKGROUND: Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. Although several biomarkers have been evaluated, histological grade remains the most valuable prognostic marker. Toll-like receptor 9 (TLR9) is an immune receptor recognizing microbial DNA. Its expression associates with prognosis or cancer properties in several cancers. This study examined the role of TLR9 in MEC. METHODS: Sixty patients with salivary gland MEC were collected from two Finnish university hospitals, and tumor samples were stained for TLR9. Salivary gland high-grade MEC cell line (UT-MUC-1) was cultured to assess TLR9 and MMP-13 expression. The function of TLR9 was studied in vitro using traditional Matrigel(®) invasion assay and novel human myoma organotypic model. RESULTS: Cancer-specific survival was related with tumor grade (P = 0.01), and there were no deaths in patients with low-grade MEC. TLR9 was expressed in 56 of 60 (93%) tumors. High TLR9 expression indicated better survival in the patient series (P = 0.002) and showed a trend for association with lower disease stage (P = 0.06) and higher differentiation grade (P = 0.068). In multivariate analysis, TLR9 expression was prognostically insignificant due to heavy correlation to disease stage and higher gradus. Treating UT-MUC-1 cells with TLR9 ligand CpG in vitro induced MMP-13 expression and invasion in Matrigel(®) invasion assay, whereas decreased invasion was seen in myoma organotypic model. CONCLUSION: Functional TLR9 is present in salivary MEC, and high level of expression may indicate good prognosis. However, more studies are needed to evaluate biological consequences of TLR9 interaction in tumor cells.
