Bai Zhigang, Wang Jin, Wang Tingting, Li Yuan, Zhao Xiaomu, Wu Guocong, Yang Yingchi, Deng Wei, Zhang Zhongtao
Cell Physiol Biochem. 2017;44(5):1882-1895. doi: 10.1159/000485877. Epub 2017 Dec 8.
BACKGROUND/AIMS: More and more reports have shown that the dysregulation of miRNAs can contribute to the progression and metastasis of human cancers. Many studies have shown that the down-regulation of the miR-495 level occurs in a variety of cancers, including colorectal cancer (CRC). However, the precise molecular mechanisms of miR-495 in CRC have not been well clarified. In the current study, we investigated the biological functions and molecular mechanisms of miR-495 in CRC cell lines.
qRT-PCR was used to determine the level of miR-495 in CRC cell lines and tissues. A miR-495 mimic and inhibitor were transfected into CRC cells, and the effects of miR-495 on the invasion and EMT were explored by qRT-PCR as well as transwell and Western blot assays. Meanwhile, luciferase assays were performed to validate Annexin A3 as a miR-495 target in CRC cells.
In our study, we found that miR-495 is down-regulated in CRC tissues and cell lines. Moreover, the low level of miR-495 was associated with increased expression of Annexin A3 in CRC tissues and cell lines. The invasion and EMT of CRC cells were suppressed by the overexpression of miR-495. However, the down-regulation of miR-495 promoted the invasion and EMT of CRC cells. Bioinformatics analysis predicted that Annexin A3 was a potential target gene of miR-495. Next, the luciferase reporter assay confirmed that miR-495 could directly target Annexin A3. Consistent with the effect of miR-495, the down-regulation of Annexin A3 by siRNA inhibited the invasion and EMT of CRC cells through the up-regulation of p53. The introduction of Annexin A3 in CRC cells partially blocked the effects of the miR-495 mimic.
The introduction of miR-495 directly targeted Annexin A3 to inhibit the invasion and EMT of CRC cells by up-regulating p53, and the down-regulation of Annexin A3 was essential for inhibiting the invasion and EMT of CRC cells by overexpressing miR-495. Overall, the re-activation of the miR-495/Annexin A3/ p53 axis may represent a new strategy for overcoming metastasis of CRC.
背景/目的：越来越多的报道表明，微小RNA（miRNA）的失调可促进人类癌症的进展和转移。许多研究表明，miR-495水平的下调发生在包括结直肠癌（CRC）在内的多种癌症中。然而，miR-495在CRC中的精确分子机制尚未完全阐明。在本研究中，我们调查了miR-495在CRC细胞系中的生物学功能和分子机制。
采用qRT-PCR检测CRC细胞系和组织中miR-495的水平。将miR-495模拟物和抑制剂转染到CRC细胞中，通过qRT-PCR、Transwell和蛋白质印迹分析探讨miR-495对侵袭和上皮-间质转化（EMT）的影响。同时，进行荧光素酶报告基因检测以验证膜联蛋白A3（Annexin A3）是CRC细胞中miR-495的靶标。
在我们的研究中，我们发现miR-495在CRC组织和细胞系中表达下调。此外，CRC组织和细胞系中miR-495的低水平与Annexin A3表达增加有关。miR-495的过表达抑制了CRC细胞的侵袭和EMT。然而，miR-495的下调促进了CRC细胞的侵袭和EMT。生物信息学分析预测Annexin A3是miR-495的潜在靶基因。接下来，荧光素酶报告基因检测证实miR-495可以直接靶向Annexin A3。与miR-495的作用一致，siRNA介导的Annexin A3下调通过上调p53抑制了CRC细胞的侵袭和EMT。在CRC细胞中引入Annexin A3部分阻断了miR-495模拟物的作用。
引入miR-495通过上调p53直接靶向Annexin A3来抑制CRC细胞的侵袭和EMT，而Annexin A3的下调对于过表达miR-495抑制CRC细胞的侵袭和EMT至关重要。总体而言，重新激活miR-495/Annexin A3/p53轴可能代表克服CRC转移的一种新策略。
