Department of Biochemistry and Molecular Biology, Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, LA 70112, USA.
Cancer Metastasis Rev. 2009 Dec;28(3-4):369-78. doi: 10.1007/s10555-009-9188-5.
MicroRNAs (miRNAs) are small noncoding, double-stranded RNA molecules that can mediate the expression of target genes with complementary sequences. About 5,300 human genes have been implicated as targets for miRNAs, making them one of the most abundant classes of regulatory genes in humans. MiRNAs recognize their target mRNAs based on sequence complementarity and act on them to cause the inhibition of protein translation by degradation of mRNA. Besides contributing to development and normal function, microRNAs have functions in various human diseases. Given the importance of miRNAs in regulating cellular differentiation and proliferation, it is not surprising that their misregulation is linked to cancer. In cancer, miRNAs function as regulatory molecules, acting as oncogenes or tumor suppressors. Amplification or overexpression of miRNAs can down-regulate tumor suppressors or other genes involved in cell differentiation, thereby contributing to tumor formation by stimulating proliferation, angiogenesis, and invasion; i.e., they act as oncogenes. Similarly, miRNAs can down-regulate different proteins with oncogenic activity; i.e., they act as tumor suppressors. This review will highlight the recent discoveries regarding miRNAs and their importance in cancer.
微小 RNA（miRNAs）是小的非编码双链 RNA 分子，可以通过与互补序列的靶基因进行表达调控。约 5300 个人类基因被认为是 miRNAs 的靶基因，这使得它们成为人类中最丰富的一类调节基因。miRNAs 基于序列互补性识别其靶 mRNAs，并作用于靶 mRNAs 导致 mRNA 降解从而抑制蛋白质翻译。除了在发育和正常功能中发挥作用外，miRNAs 在各种人类疾病中也具有功能。鉴于 miRNAs 在调节细胞分化和增殖中的重要性，miRNAs 失调与癌症有关也就不足为奇了。在癌症中，miRNAs 作为调节分子起作用，充当癌基因或肿瘤抑制基因。miRNAs 的扩增或过表达可以下调肿瘤抑制基因或其他参与细胞分化的基因，从而通过刺激增殖、血管生成和侵袭促进肿瘤形成；也就是说，它们充当癌基因。同样，miRNAs 可以下调具有致癌活性的不同蛋白质；也就是说，它们充当肿瘤抑制基因。本综述将重点介绍关于 miRNAs 的最新发现及其在癌症中的重要性。
