Peng Yang, Liu Yan-Min, Li Lu-Chun, Wang Lu-Lu, Wu Xiao-Ling
Department of Gastroenterology, Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P.R. China.
Oncol Lett. 2014 Apr;7(4):1233-1238. doi: 10.3892/ol.2014.1868. Epub 2014 Feb 11.
Epithelial-to-mesenchymal transition (EMT) is believed to be associated with cancer cell malignancy, and also to cause cancer invasion and metastasis. Recent evidence indicates that small non-protein coding RNA [microRNAs (miRNAs/miRs)] may act as powerful regulators of EMT. The present study aimed to systematically delineate miR-503 expression in gastric cancer and analyse the function of miR-503 in gastric cancer EMT. In the present study, miR-503 expression was detected in gastric cancer cell lines and gastric cancer tissues by quantitative polymerase chain reaction. Gastric cancer cell migration, invasion and proliferation capabilities were analysed by Transwell, MTT and clonability assays. The expression of mesenchymal markers, including fibronectin, vimentin, N-cadherin, SNAIL and the epithelial marker, E-cadherin, was examined by immunoblot analysis following miR-503 transfection. miR-503 expression was found to be reduced in gastric cancer cell lines compared with normal gastric mucosa cell lines, and the expression of miR-503 was upregulated in non-metastatic-derived gastric cancer cell lines compared with metastatic-derived lines. miR-503 expression levels were significantly reduced in tumour tissues in comparison with adjacent normal mucosa tissues, and the miR-503 expression levels in patients with metastases were significantly lower than those in patients without. miR-503 inhibited gastric cancer cell migration, invasion and proliferation. Fibronectin, vimentin, N-cadherin and SNAIL protein levels were decreased, but E-cadherin expression was increased in an AGS cell line transfected with miR-503. Taken together, the present findings indicate that miR-503 acts as a novel tumour suppressor gene in gastric cancer and can inhibit EMT in gastric cancer cells.
上皮-间质转化（EMT）被认为与癌细胞的恶性程度相关，并且还会导致癌症的侵袭和转移。最近的证据表明，小型非蛋白质编码RNA[微小RNA（miRNA/miR）]可能是EMT的强大调节因子。本研究旨在系统地描述miR-503在胃癌中的表达情况，并分析miR-503在胃癌EMT中的作用。在本研究中，通过定量聚合酶链反应检测胃癌细胞系和胃癌组织中miR-503的表达。通过Transwell、MTT和克隆能力分析来检测胃癌细胞的迁移、侵袭和增殖能力。在转染miR-503后，通过免疫印迹分析检测包括纤连蛋白、波形蛋白、N-钙黏蛋白、SNAIL等间充质标志物以及上皮标志物E-钙黏蛋白的表达。与正常胃黏膜细胞系相比，发现胃癌细胞系中miR-503的表达降低，并且与转移性来源的胃癌细胞系相比，非转移性来源的胃癌细胞系中miR-503的表达上调。与相邻的正常黏膜组织相比，肿瘤组织中miR-503的表达水平显著降低，并且有转移的患者中miR-503的表达水平明显低于无转移的患者。miR-503抑制胃癌细胞的迁移、侵袭和增殖。在转染了miR-503的AGS细胞系中，纤连蛋白、波形蛋白、N-钙黏蛋白和SNAIL的蛋白水平降低，但E-钙黏蛋白的表达增加。综上所述，本研究结果表明miR-503在胃癌中作为一种新的肿瘤抑制基因发挥作用，并且可以抑制胃癌细胞中的EMT。
