Libório-Kimura Tatiana N, Jung Hyun Min, Chan Edward K L
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.
Department of Oral Biology, University of Florida, P.O. Box 100424, Gainesville, FL 32610-0424, USA.
Oral Oncol. 2015 Feb;51(2):151-7. doi: 10.1016/j.oraloncology.2014.11.019. Epub 2014 Dec 12.
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.
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.
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.
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.
在我们的口腔癌筛查中，miR - 494被鉴定为表达最显著下调的微小RNA（miRNA）候选分子。本研究旨在验证miR - 494在口腔癌中是否具有功能性作用。
对口腔肿瘤RNA和口腔癌细胞系进行miRNA定量分析。基于miR - 494靶标的生物信息学分析以及先前关于HOXA10在口腔癌中过表达的报道，选择HOXA10进行进一步分析。在SCC - 25（舌癌）、CAL 27（舌癌）和FaDu（咽癌）癌细胞中进行miRNA模拟物和抑制剂的瞬时转染，并研究miR - 494对HOXA10的调控作用。采用双荧光素酶报告基因检测法验证报告细胞中miR - 494与HOXA10之间的相互作用。检测miR - 494对细胞增殖的影响。
我们的数据显示，与正常组织相比，口腔癌中miR - 494表达下调而HOXA10表达上调。在人体组织中观察到miR - 494与HOXA10呈负相关（p<0.05）。在所有癌细胞系中瞬时转染miR - 494均显著降低了HOXA10 mRNA的表达。含有HOXA10 3'UTR的荧光素酶报告基因显示，miR - 494使其荧光素酶活性显著降低，表明HOXA10与miR - 494之间存在直接相互作用。在转染miR - 494的舌癌细胞中，细胞增殖显著降低。
miR - 494抑制HOXA10的表达，并降低口腔癌细胞的增殖。这些数据进一步证明了miR - 494作为口腔癌中肿瘤抑制性miRNA的作用。
