Down-regulation of some miRNAs by degrading their precursors contributes to anti-cancer effect of mistletoe lectin-I
Down-regulation of some miRNAs by degrading their precursors contributes to anti-cancer effect of mistletoe lectin-I
复制标题
通过降解某些 miRNA 的前体来下调某些 miRNA，有助于槲寄生凝集素-I 的抗癌作用
DOI：
10.1111/j.1476-5381.2010.01042.x
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发表时间：
2011-01-01
影响因子：
7.3
通讯作者：
Yuan, Shou-Jun
中科院分区：
文献类型：
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作者：
Li, Lin-Na;Zhang, Hua-Dong;Yuan, Shou-Jun
槲寄生凝集素-I（ML-I）是槲寄生提取物的主要抗癌成分，最初被认为仅作用于28 S rRNA。本研究旨在探讨从槲寄生中提取的ML-I-CM-1对部分miRNAs的下调作用及其机制。实验方法体外和体内研究CM-1对结直肠癌细胞的抗癌作用。通过miRNA芯片分析和qRT-PCR分析验证CM-1下调的miRNA。分别通过qRT-PCR和酶活性测定来确定宿主基因转录的抑制或通过前体降解的抑制。采用qRT-PCR、Western blot和免疫组织化学方法检测其靶基因及下游效应子的表达。在HEK-293细胞中，稳定转染不同水平的miRNAs，检测细胞增殖情况，发现KEY TSCM-1在体内外均对CLY和HT-29细胞具有显著的抗肿瘤活性。miR-135 a和b是被CM-1下调最多的miRNA。它们的宿主基因转录在很大程度上被上调，而它们的前体被CM-1直接降解。其靶基因腺瘤性结肠息肉病的表达和相关效应因子β-连环蛋白的磷酸化均显著上调。CM-1对高miR-135 a和b水平的衍生HEK-293细胞的IC 50值比对照细胞低2-4倍。结论和意义SCM-1通过降解其前体下调一些miRNA，这有助于其突出的抗癌活性。第346-348章这件事要查看此评论，请访问http://dx.doi.org/10.1111/j.1476-5381.2010.01075.x。
BACKGROUND AND PURPOSEMistletoe lectin-I (ML-I), the main anti-cancer component of mistletoe extracts, was originally thought to act exclusively on 28S rRNA. Here, we investigate the down-regulating effect and mechanism of CM-1, an ML-I isolated from Chinese mistletoe, on some miRNAs.EXPERIMENTAL APPROACHThe anti-cancer effects of CM-1 were assessed in vitro and in vivo in colorectal cancer cells. The miRNAs down-regulated by CM-1 were identified by miRNA microarray assay and validated by qRT-PCR analysis. The suppression of host gene transcription or by degradation of precursors was determined by qRT-PCR and enzyme activity assays respectively. The qRT-PCR, Western blot and immunohistochemistry were used to examine the expression of their target gene and related downstream effector. Cell proliferation was assayed in stably transfected HEK-293 cells with different levels of these miRNAs.KEY RESULTSCM-1 showed prominent anti-neoplastic activity towards CLY and HT-29 cells both in vitro and in vivo. The miR-135a&b were the miRNAs most down-regulated by CM-1. Their host gene transcription was largely up-regulated, while their precursors were degraded directly by CM-1. The expression of their target gene adenomatous polyposis coli and the phosphorylation of related effector beta-catenin were both significantly up-regulated. The IC50 values of CM-1 on derivative HEK-293 cells with high miR-135a&b levels were 2-4 times lower than that of control cells.CONCLUSIONS AND IMPLICATIONSCM-1 down-regulated some miRNAs by degrading their precursors, which contributes to its prominent anti-cancer activity.LINKED ARTICLEThis article is commented on by Rushworth, pp. 346-348 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2010.01075.x.