1] Department of Colorectal Surgery, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China [2] Department of General Surgery, Second Affiliated Hospital to Yangzhou University School of Medicine, No. 45 Taizhou Road, Yangzhou 225001, China.
Department of Gastroenterology, Changhai Hospital affiliated to Second Military Medical University, No. 168 Changhai Road, Shanghai 200433, China.
Br J Cancer. 2014 Jan 21;110(2):450-8. doi: 10.1038/bjc.2013.724. Epub 2013 Nov 26.
Growing evidence suggests that miR-29a has an important role in regulating tumourigenesis and development of various types of cancer. However, the role and the underlying mechanism of miR-29a in colorectal cancer (CRC) remain largely unknown.
MiR-29a targeted gene was identified by the luciferase assay and western blot. MiR-29a function was analysed by invasion assays and the orthotopic transplantation mouse model. The miR-29a pathway was assayed by real-time PCR, western blot and chip analysis.
KLF4 was identified as a direct target gene of miR-29a. MiR-29a promoted CRC cell invasion, which was blocked by re-expression of KLF4. In addition, MMP2 was identified as a novel direct target of KLF4. Both miR-29a overexpression and KLF4 knockdown promoted MMP2 expression but inhibited E-cadherin expression. Furthermore, clinical data indicated that both miR-29a high expression and KLF4 mRNA low expression were associated with metastasis and poor prognosis in CRC patients, and KLF4 protein expression was inversely correlated with MMP2 but positively correlated with E-cad protein expression.
Increased expression of miR-29a promoted CRC metastasis by regulating MMP2/E-cad through direct targeting KLF4, which highlights the potential of the miR-29a inhibitor as a novel agent against CRC metastasis.
越来越多的证据表明，miR-29a 在调节各种类型癌症的肿瘤发生和发展方面具有重要作用。然而，miR-29a 在结直肠癌（CRC）中的作用及其潜在机制在很大程度上仍不清楚。
通过荧光素酶测定和 Western blot 鉴定 miR-29a 的靶基因。通过侵袭实验和原位移植小鼠模型分析 miR-29a 的功能。通过实时 PCR、Western blot 和芯片分析检测 miR-29a 通路。
KLF4 被鉴定为 miR-29a 的直接靶基因。miR-29a 促进 CRC 细胞侵袭，而 KLF4 的重新表达则阻止了这一过程。此外，MMP2 被鉴定为 KLF4 的一个新的直接靶基因。miR-29a 过表达和 KLF4 敲低均促进 MMP2 表达，抑制 E-钙黏蛋白表达。此外，临床数据表明，miR-29a 高表达和 KLF4 mRNA 低表达与 CRC 患者的转移和预后不良有关，而 KLF4 蛋白表达与 MMP2 呈负相关，与 E-钙蛋白表达呈正相关。
miR-29a 的表达增加通过直接靶向 KLF4 调节 MMP2/E-钙黏蛋白促进 CRC 转移，这凸显了 miR-29a 抑制剂作为一种新型 CRC 转移治疗剂的潜力。
