Department of Tumor Biology, Division of Bioscience, Center for Advanced Medical Science, School of Medicine, Iwate Medical University, Morioka 020-8505, Japan.
Int J Oncol. 2011 Sep;39(3):665-72. doi: 10.3892/ijo.2011.1084. Epub 2011 Jun 16.
MicroRNAs (miRNAs) are small non-coding RNAs whose aberrations are involved in the initiation and progression of human cancers. To seek unique miRNAs contributing to melanoma tumorigenesis, we investigated the global miRNA expression profile of 7 melanoma cell lines and 3 primary cultures of neonatal human epidermal melanocytes (NHEMs) using the stem-loop real-time PCR method. We found 7 miRNAs that were commonly downregulated and 18 that were upregulated in all of the melanoma cell lines in comparison with the 3 primary cultures of NHEMs. We focused on one commonly downregulated miRNA (miR-211), and analyzed its relationship to the expression of preferentially expressed antigen of melanoma (PRAME) protein, which is a potential target of miR-211. We found that all melanoma cell lines exhibited marked down--regulation of miR-211 and upregulation of PRAME mRNA/protein expression in comparison with NHEMs (P<0.05). A significant inverse correlation between miR-211 and PRAME protein expression was found in melanoma cell lines and primary cultures of NHEMs (correlation coefficient of -0.733, P<0.05). We demonstrated that overexpression of miR-211 induced a reduction of PRAME protein levels, and confirmed the target specificity between miR-211 and PRAME by luciferase reporter assay. These results suggest that downregulation of miR-211 may be partly involved in aberrant expression of the PRAME protein in melanoma cells.
微小 RNA（miRNA）是小的非编码 RNA，其异常参与了人类癌症的发生和发展。为了寻找有助于黑色素瘤发生的独特 miRNA，我们采用茎环实时 PCR 法，研究了 7 株黑色素瘤细胞系和 3 株新生人表皮黑素细胞（NHEM）原代培养物的全球 miRNA 表达谱。与 3 株 NHEM 原代培养物相比，我们发现 7 种 miRNA 普遍下调，18 种 miRNA 上调。我们关注一个普遍下调的 miRNA（miR-211），并分析其与黑色素瘤优先表达抗原（PRAME）蛋白表达的关系，PRAME 蛋白是 miR-211 的潜在靶标。我们发现与 NHEM 相比，所有黑色素瘤细胞系均表现出 miR-211 的明显下调和 PRAME mRNA/蛋白表达的上调（P<0.05）。在黑色素瘤细胞系和 NHEM 原代培养物中，miR-211 与 PRAME 蛋白表达之间存在显著的负相关（相关系数为-0.733，P<0.05）。我们证明了 miR-211 的过表达诱导了 PRAME 蛋白水平的降低，并通过荧光素酶报告基因检测证实了 miR-211 和 PRAME 之间的靶特异性。这些结果表明，miR-211 的下调可能部分参与了黑色素瘤细胞中 PRAME 蛋白的异常表达。
