Tatiana N Libório-Kimura1, Hyun Min Jung2, Edward K L Chan3. 1. Department of Oral Biology, University of Florida, P.O. Box 100424, Gainesville, FL 32610-0424, USA; Department of Pathology and Legal Medicine, Federal University of Amazonas, Av. Valdemar Pedrosa, 1097, CEP 69020-160 AM, Brazil. Electronic address: tliborio@ufam.edu.br. 2. Department of Oral Biology, University of Florida, P.O. Box 100424, Gainesville, FL 32610-0424, USA. Electronic address: hyunmin.jung@nih.gov. 3. Department of Oral Biology, University of Florida, P.O. Box 100424, Gainesville, FL 32610-0424, USA. Electronic address: echan@ufl.edu.
Abstract
OBJECTIVES: miR-494 was identified as a candidate of the most significantly underexpressed microRNAs (miRNAs) in our oral cancer screen. The aim of this study was to validate whether miR-494 has a functional role in oral cancer. METHODS: Quantitative miRNA analyses were performed on oral tumor RNA and oral cancer cell lines. HOXA10 was selected for further analysis based on bioinformatics analysis of miR-494 targets and a previous report of overexpression of HOXA10 in oral cancer. Transient transfection of miRNA-mimic and inhibitor were performed in SCC-25 (tongue), CAL 27 (tongue), and FaDu (pharynx) cancer cells and regulation of HOXA10 by miR-494 was investigated. Dual luciferase assay was used to verify the interaction between miR-494 and HOXA10 in reporter cells. The effect of miR-494 on cell proliferation was examined. RESULTS: Our data showed that miR-494 was underexpressed whereas HOXA10 was overexpressed in oral cancer compared to normal tissues. An inverse correlation between miR-494 and HOXA10 was observed in the human tissues (p<0.05). Transient transfection of miR-494 in all cancer cell lines significantly reduced the expression of HOXA10 mRNA. The luciferase reporter that contains the 3'UTR of HOXA10 showed a significantly reduced luciferase activity by miR-494 indicating a direct interaction between HOXA10 and miR-494. Significant reduction in cell proliferation was demonstrated in tongue cancer cells transfected with miR-494. CONCLUSION: miR-494 repressed the expression of HOXA10 and also reduced the proliferation of oral cancer cells. These data give more evidence of the role of miR-494 as a tumor suppressor miRNA in oral cancer.
OBJECTIVES:miR-494 was identified as a candidate of the most significantly underexpressed microRNAs (miRNAs) in our oral cancer screen. The aim of this study was to validate whether miR-494 has a functional role in oral cancer. METHODS: Quantitative miRNA analyses were performed on oral tumor RNA and oral cancer cell lines. HOXA10 was selected for further analysis based on bioinformatics analysis of miR-494 targets and a previous report of overexpression of HOXA10 in oral cancer. Transient transfection of miRNA-mimic and inhibitor were performed in SCC-25 (tongue), CAL 27 (tongue), and FaDu (pharynx) cancer cells and regulation of HOXA10 by miR-494 was investigated. Dual luciferase assay was used to verify the interaction between miR-494 and HOXA10 in reporter cells. The effect of miR-494 on cell proliferation was examined. RESULTS: Our data showed that miR-494 was underexpressed whereas HOXA10 was overexpressed in oral cancer compared to normal tissues. An inverse correlation between miR-494 and HOXA10 was observed in the human tissues (p<0.05). Transient transfection of miR-494 in all cancer cell lines significantly reduced the expression of HOXA10 mRNA. The luciferase reporter that contains the 3'UTR of HOXA10 showed a significantly reduced luciferase activity by miR-494 indicating a direct interaction between HOXA10 and miR-494. Significant reduction in cell proliferation was demonstrated in tongue cancer cells transfected with miR-494. CONCLUSION:miR-494 repressed the expression of HOXA10 and also reduced the proliferation of oral cancer cells. These data give more evidence of the role of miR-494 as a tumor suppressor miRNA in oral cancer.
Authors: Manoela Carrera; Carolina C Bitu; Carine Ervolino de Oliveira; Nilva K Cervigne; Edgard Graner; Aki Manninen; Tuula Salo; Ricardo D Coletta Journal: Int J Clin Exp Pathol Date: 2015-04-01