ABSTRACT
Annexin A1 (ANXA1) down-regulation is an early and frequent event in the development of head and neck squamous cell carcinomas (HNSCC). In an attempt to identify the underlying mechanisms of reduced ANXA1 protein expression, this study investigated ANXA1 mRNA expression in HNSCC specimens by both in situ hybridization and RT-qPCR. Results showed a perfect concordance between the pattern of ANXA1 mRNA and protein detected by immunofluorescence in tumors, precancerous lesions and normal epithelia, reflecting that ANXA1 down-regulation occurs at transcriptional level. We also found that both miR-196a and miR-196b levels inversely correlated with ANXA1 mRNA levels in paired HNSCC tissue samples and patient-matched normal mucosa. In addition, endogenous levels of ANXA1 mRNA and protein were consistently and significantly down-regulated upon miR-196a and miR-196b over-expression in various HNSCC-derived cell lines. The direct interaction of both mature miR-196a and miR-196b was further confirmed by transfection with Anxa1 3'UTR constructs. Combined bioinformatics and functional analysis of ANXA1 promoter activity contributed to identify key regions and potential mediators of ANXA1 transcriptional control. This study unveils that, in addition to miR-196a, miR-196b also directly targets ANXA1 in HNSCC.
Subject(s)
Annexin A1/genetics , Carcinoma, Squamous Cell/genetics , Gene Expression Regulation, Neoplastic , Head and Neck Neoplasms/genetics , Annexin A1/metabolism , Carcinoma, Squamous Cell/metabolism , Carcinoma, Squamous Cell/pathology , Cell Line, Tumor , Down-Regulation , Head and Neck Neoplasms/metabolism , Head and Neck Neoplasms/pathology , Humans , MicroRNAs/genetics , MicroRNAs/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolismABSTRACT
Annexin A2 is a highly expressed gene with important roles in cell membrane physiology and is frequently dysregulated in cancer. The objective of this study was to determine the pattern of expression and prognostic significance of annexin A2 protein in head and neck squamous cell carcinoma. We assessed both quantitative changes and qualitative distribution of annexin A2 mRNA and protein expression in normal and diseased tissues by immunohistochemistry, immunofluorescence and in situ hybridization. Annexin A2 expression was confined to the basal and suprabasal cells of normal epithelium and the protein cellular location was consistently observed at the cell membrane. Expression levels correlated with histopathological grade, showing significant suppression in moderately and poorly differentiated tumours. We conclude that annexin A2 exhibits a characteristic pattern of expression, distinct from other annexins and suggestive of a cell-specific functional role. The marked reduction of annexin A2 in poorly differentiated tumours and dysplastic tissue is expected to result in a loss of function aimed at the coordination of membrane signalling enzyme complexes, actin polymerization and extracellular matrix proteolysis. The phenotypic consequences may become manifest in an alteration of epithelial tissue growth and remodelling with secondary influence on tumour development, progression and metastasis.
Subject(s)
Annexin A2/metabolism , Carcinoma, Squamous Cell/metabolism , Down-Regulation , Head and Neck Neoplasms/metabolism , Epithelial Cells/metabolism , Fluorescent Antibody Technique , Humans , In Situ Hybridization , Precancerous Conditions/metabolismABSTRACT
OBJECTIVE: Over-expression of annexin A2 (ANXA2) has been reported in various cancers. However, no data are available on the expression of this protein in head and neck squamous cell carcinomas (HNSCC). The objective of this preliminary study is to investigate the expression of ANXA2 in these carcinomas. MATERIAL AND METHOD: ANXA2 expression was analyzed by immunohistochemistry in paraffin-embedded sections from 9 patients with premalignant lesions and 21 patients with HNSCC. RESULTS: All dysplastic tissues showed significantly reduced ANXA2 expression compared to normal tissue. In contrast, ANXA2 expression was observed in all but one of the tumours studied. There was a significant correlation of lower ANXA2 expression with a poorer histological differentiation, larger tumours, and nodal metastases. CONCLUSIONS: Our data show for the first time that ANXA2 is expressed in head and neck squamous cell carcinomas and that its expression seems to be related with the degree of differentiation status of these tumours.
Subject(s)
Annexin A2/biosynthesis , Carcinoma, Squamous Cell/metabolism , Head and Neck Neoplasms/metabolism , Female , Humans , Male , Middle AgedABSTRACT
Objetivo: La expresión de la anexina A2 (ANXA2) se ha hallado elevada en varios cánceres. Sin embargo, no hay datos disponibles de la expresión de esta proteína en los carcinomas epidermoides de cabeza y cuello. El objetivo de este estudio preliminar es investigar la expresión de la ANXA2 en estos carcinomas. Material y método: Se analizó la expresión de la ANXA2 mediante inmunohistoquímica en muestras incluidas en parafina de 9 lesiones premalignas y 21 carcinomas epidermoides de cabeza y cuello. Resultados: Todas las lesiones con displasia mostraron una reducción en la expresión de la ANXA2 respecto al tejido normal. En contraste, se apreció expresión de la ANXA2 en todos menos uno de los tumores estudiados. La disminución de la expresión de la ANXA2 en los carcinomas se correlacionó de forma significativa con una peor diferenciación histológica, con tumores de mayor tamaño y con metástasis ganglionares. Conclusiones: Nuestros datos muestran por primera vez que la ANXA2 se expresa en los carcinomas epidermoides de cabeza y cuello e indican que su expresión se relaciona con el grado de diferenciación de estos tumores
Objective: Over-expression of annexin A2 (ANXA2) has been reported in various cancers. However, no data are available on the expression of this protein in head and neck squamous cell carcinomas (HNSCC). The objective of this preliminary study is to investigate the expression of ANXA2 in these carcinomas. Material and method: ANXA2 expression was analyzed by immunohistochemistry in paraffin-embedded sections from 9 patients with premalignant lesions and 21 patients with HNSCC. Results: All dysplastic tissues showed significantly reduced ANXA2 expression compared to normal tissue. In contrast, ANXA2 expression was observed in all but one of the tumours studied. There was a significant correlation of lower ANXA2 expression with a poorer histological differentiation, larger tumours, and nodal metastases. Conclusions: Our data show for the first time that ANXA2 is expressed in head and neck squamous cell carcinomas and that its expression seems to be related with the degree of differentiation status of these tumours
