Wang Yu, Lee Caroline G L
Department of Biochemistry, National University of Singapore, Singapore.
J Cell Mol Med. 2009 Jan;13(1):12-23. doi: 10.1111/j.1582-4934.2008.00510.x.
MicroRNAs (miRs) are small non-coding RNAs regulating gene expression at the post-transcriptional and/or translational levels. miRs play important roles in diverse biological processes, including development, cell differentiation, proliferation and apoptosis. Recent evidence has shown that miR loci frequently map to cancer-associated genomic regions and deregulated miR expression profiles are associated with many cancer types, implicating miRs in crucial processes that lead to tumourigenesis. Here, we review the current findings about miRs and tumourigenesis, focusing on their involvement in the apoptosis pathway. A significant observation is that greater than one-quarter of all known human miRs were reported to be deregulated in at least one cancer type. The expression of a subset of miRs (e.g. miR-21 and miR-155) was found to be consistently up-regulated, whereas another subset of miRs (e.g.miR-143 and miR-145) was consistently down-regulated across different cancer types suggesting their involvement in regulating common cellular processes whose deregulation may lead to tumourigenesis. Several miRs were implicated to play roles in cell proliferation and apoptosis. Some miRs, such as miR-29b and miR-15-16, influence only the apoptotic pathway, whereas others including let-7/miR-98 and miR-17-92 may play roles in both the apoptotic and cell-proliferation pathways. In conclusion, although our current understanding of the functions of miRs is still fragmentary, taken together, this review highlights the complex and intricate roles that miRs play in the regulation of cellular processes. Perturbation of the expression of miRs may thus lead to tumourigenesis.
微小RNA（miR）是一类小的非编码RNA，在转录后和/或翻译水平上调节基因表达。miR在多种生物学过程中发挥重要作用，包括发育、细胞分化、增殖和凋亡。最近的证据表明，miR基因座经常定位于与癌症相关的基因组区域，而失调的miR表达谱与多种癌症类型相关，这表明miR参与了导致肿瘤发生的关键过程。在这里，我们综述了关于miR与肿瘤发生的当前研究结果，重点关注它们在凋亡途径中的作用。一个重要的发现是，据报道，在至少一种癌症类型中，超过四分之一的已知人类miR表达失调。发现一部分miR（如miR-21和miR-155）的表达持续上调，而另一部分miR（如miR-143和miR-145）在不同癌症类型中持续下调，这表明它们参与调节可能导致肿瘤发生的常见细胞过程。几种miR被认为在细胞增殖和凋亡中发挥作用。一些miR，如miR-29b和miR-15-16，仅影响凋亡途径，而其他miR，包括let-7/miR-98和miR-17-92，可能在凋亡和细胞增殖途径中都发挥作用。总之，尽管我们目前对miR功能的理解仍然是碎片化的，但综合来看，这篇综述强调了miR在细胞过程调节中所起的复杂而微妙的作用。因此，miR表达的扰动可能导致肿瘤发生。
