Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
Gastroenterology. 2012 Apr;142(4):886-896.e9. doi: 10.1053/j.gastro.2011.12.047. Epub 2012 Jan 10.
BACKGROUND & AIMS: MicroRNAs (miRNAs) can promote or inhibit tumor growth and are therefore being developed as targets for cancer therapies. They are diverse not only in the messenger RNAs (mRNA) they target, but in their production; the same hairpin RNA structure can generate mature products from each strand, termed 5p and 3p, that can bind different mRNAs. We analyzed the expression, functions, and mechanisms of miR-28-5p and miR-28-3p in colorectal cancer (CRC) cells.
We measured levels of miR-28-5p and miR-28-3p expression in 108 CRC and 49 normal colorectal samples (47 paired) by reverse transcription, quantitative real-time polymerase chain reaction. The roles of miR-28 in CRC development were studied using cultured HCT116, RKO, and SW480 cells and tumor xenograft analyses in immunodeficient mice; their mRNA targets were also investigated.
miR-28-5p and miR-28-3p were down-regulated in CRC samples compared with normal colon samples. Overexpression of miRNAs in CRC cells had different effects and the miRNAs interacted with different mRNAs: miR-28-5p altered expression of CCND1 and HOXB3, whereas miR-28-3p bound NM23-H1. Overexpression of miR-28-5p reduced CRC cell proliferation, migration, and invasion in vitro, whereas miR-28-3p increased CRC cell migration and invasion in vitro. CRC cells overexpressing miR-28 developed tumors more slowly in mice compared with control cells, but miR-28 promoted tumor metastasis in mice.
miR-28-5p and miR-28-3p are transcribed from the same RNA hairpin and are down-regulated in CRC cells. Overexpression of each has different effects on CRC cell proliferation and migration. Such information has a direct application for the design of miRNA gene therapy trials.
MicroRNAs（miRNAs）可以促进或抑制肿瘤生长，因此被开发为癌症治疗的靶点。它们不仅在靶向的信使 RNA（mRNA）上有所不同，而且在其产生过程中也存在多样性；同一发夹 RNA 结构可以从每条链上生成成熟产物，分别称为 5p 和 3p，可以结合不同的 mRNA。我们分析了 miRNA-28-5p 和 miRNA-28-3p 在结直肠癌细胞（CRC）中的表达、功能和机制。
通过逆转录、实时定量聚合酶链反应，我们测量了 108 例 CRC 和 49 例正常结直肠样本（47 对）中 miR-28-5p 和 miR-28-3p 的表达水平。我们使用培养的 HCT116、RKO 和 SW480 细胞以及免疫缺陷小鼠的肿瘤异种移植分析来研究 miR-28 在 CRC 发展中的作用；还研究了它们的 mRNA 靶标。
与正常结肠样本相比，CRC 样本中 miR-28-5p 和 miR-28-3p 的表达下调。CRC 细胞中 miRNA 的过表达具有不同的影响，并且 miRNA 与不同的 mRNA 相互作用：miR-28-5p 改变了 CCND1 和 HOXB3 的表达，而 miR-28-3p 结合了 NM23-H1。miR-28-5p 的过表达降低了 CRC 细胞在体外的增殖、迁移和侵袭能力，而 miR-28-3p 增加了 CRC 细胞的迁移和侵袭能力。与对照细胞相比，过表达 miR-28 的 CRC 细胞在小鼠中形成肿瘤的速度较慢，但 miR-28 促进了小鼠中的肿瘤转移。
miR-28-5p 和 miR-28-3p 由同一 RNA 发夹转录而来，在 CRC 细胞中表达下调。每种 miRNA 的过表达对 CRC 细胞的增殖和迁移都有不同的影响。这些信息直接应用于 miRNA 基因治疗试验的设计。
