Cancer Center & Department of Pathology, Nanjing Medical University, Nanjing, China.
Cell Biochem Biophys. 2012 Jan;62(1):237-44. doi: 10.1007/s12013-011-9263-8.
microRNA-199a (miR-199a) is a highly conserved miRNA, always deregulated in numerous human tumors. The results of microarray analysis indicated that miR-199a was frequently downregulated in hepatocellular carcinoma (HCC). The expression levels of miR-199a in 11 pairs of matched HCC neoplastic and adjacent non-neoplastic tissues, 5 HCC cell lines and liver cell line L02 were examined by quantitative real-time PCR analysis. We found miR-199a was significantly down-regulated in HCC tissues when compared with pair-matched adjacent non-tumor tissues. We also found the expression level of miR-199a was also substantially decreased in several human HCC cell lines including SMMC-7721, BEL-7402, BEL-7701, MHCC97H, and HepG2. To investigate the role of miR-199a in tumorigenesis, we developed a lentiviral vector for the expression of pre-miR-199a (Lenti-miR-199a). Lenti-miR-199a inhibited HCC cell proliferation in vitro and in vivo. Compared to parental cells or cells transfected with a control vector, the overexpression of microRNA-199a in the HCC cell lines HepG2 stably was showed to reduce cell proliferation in vitro and in vivo. Luciferase reporter assay revealed the regulation of miR-199a on 3'-UTR of HIF-1α. Further investigation confirmed that miR-199a significantly reduced the endogenous protein level of HIF-1α in hypoxia. MiR-199a inhibits cell proliferation in vitro and in vivo partly through down-regulation of HIF-1α in human HCC. Thus, these studies provide an important new insight into the pathogenesis of human HCC and it may open a new perspective for the development of effective gene therapy for human HCC.
微小 RNA-199a（miR-199a）是一种高度保守的 miRNA，在许多人类肿瘤中经常失调。微阵列分析的结果表明，miR-199a 在肝细胞癌（HCC）中经常下调。通过定量实时 PCR 分析检测了 11 对配对的 HCC 肿瘤和相邻非肿瘤组织、5 种 HCC 细胞系和肝细胞系 L02 中 miR-199a 的表达水平。我们发现 miR-199a 在 HCC 组织中与配对的相邻非肿瘤组织相比显著下调。我们还发现 miR-199a 的表达水平在包括 SMMC-7721、BEL-7402、BEL-7701、MHCC97H 和 HepG2 在内的几种人 HCC 细胞系中也显著降低。为了研究 miR-199a 在肿瘤发生中的作用，我们开发了一种表达前 miR-199a 的慢病毒载体（Lenti-miR-199a）。Lenti-miR-199a 抑制 HCC 细胞的体外和体内增殖。与亲本细胞或转染对照载体的细胞相比，HCC 细胞系 HepG2 中 microRNA-199a 的过表达显示可减少体外和体内的细胞增殖。荧光素酶报告基因检测揭示了 miR-199a 对 HIF-1α 3'-UTR 的调节。进一步的研究证实，miR-199a 可显著降低缺氧条件下 HIF-1α 的内源性蛋白水平。miR-199a 通过下调 HIF-1α 可部分抑制体外和体内的细胞增殖。因此，这些研究为人类 HCC 的发病机制提供了重要的新见解，并可能为人类 HCC 的有效基因治疗开辟新的视角。
