Kawakita Akiko, Yanamoto Souichi, Yamada Shin-Ichi, Naruse Tomofumi, Takahashi Hidenori, Kawasaki Goro, Umeda Masahiro
Department of Clinical Oral Oncology, Unit of Translational Medicine, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8588, Japan.
Pathol Oncol Res. 2014 Apr;20(2):253-61. doi: 10.1007/s12253-013-9689-y. Epub 2013 Sep 3.
MicroRNA-21 (miR-21) is overexpressed in a wide variety of cancers and has been related to cellular proliferation, apoptosis, and invasion; however, the function of miR-21 is unknown in oral tongue squamous cell carcinoma (OTSCC). The purpose of this study was to examine miR-21 expression in OTSCC, correlate it with clinicopathological factors, and investigate its contribution to OTSCC cell invasion. MiR-21 expression in 79 primary OTSCCs was evaluated using locked nucleic acid in situ hybridization, and correlation was examined with the clinicopathological factors. To determine the miR-21 target, we searched for molecular genes involved in tumor invasion using the commonly cited prediction program miRanda. In an OTSCC cell line, SCC25 cells, we further evaluated whether miR-21 contributes to cell invasiveness by blocking its expression with a specific knockdown LNA probe and confirmed the direct target by Matrigel invasion assay and Western blotting. MiR-21 overexpression was detected in 60 of 79 cases (75.9 %) and correlated with the pattern of invasion (P = 0.016). We selected DKK2 as a Wnt/antagonist involved in tumor invasion. MiR-21 overexpression was significantly correlated with the DKK2-/β-catenin- immunohistochemical phenotype. Knockdown of miR-21 significantly decreased the invasion potential of SCC25 cells with up-regulated DKK2. It was found that miR-21 is overexpressed and associated with tumor invasion in OTSCC, and that miR-21 promotes OTSCC cell invasion via the Wnt/β-catenin pathway by targeting DKK2 in vitro. These results suggest that miR-21 may be a potential therapeutic target for OTSCC treatment.
微小RNA-21（miR-21）在多种癌症中均有过表达，且与细胞增殖、凋亡及侵袭相关；然而，miR-21在口腔舌鳞状细胞癌（OTSCC）中的功能尚不清楚。本研究旨在检测OTSCC中miR-21的表达，将其与临床病理因素相关联，并研究其对OTSCC细胞侵袭的作用。采用锁核酸原位杂交技术评估79例原发性OTSCC中miR-21的表达，并分析其与临床病理因素的相关性。为确定miR-21的靶标，我们使用常用的预测程序miRanda搜索参与肿瘤侵袭的分子基因。在OTSCC细胞系SCC25细胞中，我们通过用特异性敲低锁核酸探针阻断其表达，进一步评估miR-21是否有助于细胞侵袭，并通过基质胶侵袭试验和蛋白质免疫印迹法确认直接靶标。7管9例（75.9%）中检测到miR-21过表达，且与侵袭模式相关（P = 0.016）。我们选择DKK2作为参与肿瘤侵袭的Wnt拮抗剂。miR-21过表达与DKK2-/β-连环蛋白免疫组化表型显著相关。敲低miR-21可显著降低DKK2上调的SCC25细胞的侵袭潜能。研究发现，miR-21在OTSCC中过表达并与肿瘤侵袭相关，且miR-21在体外通过靶向DKK2经由Wnt/β-连环蛋白途径促进OTSCC细胞侵袭。这些结果表明，miR-21可能是OTSCC治疗的潜在靶点。
