Authors' Affiliations: Department of Pathology; bioMérieux Laboratory, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College; Institute of Pathology; Institutes of Biomedical Sciences, Fudan University, Shanghai; Wuxi Oncology Institute, the Affiliated Hospital of Jiangnan University, Wuxi; State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University School of Medicine; and Department of Oncology, Ren Ji Hospital, Shanghai Jiao Tong University, Shanghai, China.
Clin Cancer Res. 2014 Mar 1;20(5):1146-57. doi: 10.1158/1078-0432.CCR-13-1023. Epub 2013 Dec 10.
MicroRNAs (miRNA) that are strongly implicated in carcinogenesis have recently reshaped our understanding of the role of non-protein-coding RNAs. Here, we focused on the function and molecular mechanism of miR-202-3p and its potential clinical application in colorectal cancer.
miR-202-3p expression was determined by quantitative reverse transcriptase PCR (qRT-PCR) in 94 colorectal cancer tissues and corresponding noncancerous tissues (NCT). Cell proliferation and colony formation assays in vitro and xenograft experiments in vivo were used to evaluate the effect of miR-202-3p on colorectal cancer cell proliferation. Luciferase assay and Western blot analysis were performed to validate the potential targets of miR-202-3p after the preliminary screening by online prediction and microarray analysis. The mRNA and protein levels of target genes were detected by qRT-PCR and immunohistochemical staining. The copy number of pre-miR-202 was measured by quantitative PCR.
First, miR-202-3p was significantly downregulated in 46.7% colorectal cancer samples compared with NCTs. The overexpression of miR-202-3p inhibited colorectal cancer cell growth in vitro and repressed tumorigenesis in nude mice. Then, miR-202-3p downregulated ADP-ribosylation factor-like 5A (ARL5A) protein level by binding to its 3' untranslated region, and knockdown of ARL5A phenocopied the proliferation inhibition effect of miR-202-3p. Furthermore, both of ARL5A mRNA and protein levels were upregulated in colorectal cancer samples compared with NCTs and high ARL5A protein levels predicted a poor prognosis.
miR-202-3p might function as a tumor suppressor in colorectal cancer, and ARL5A, the functional target of miR-202-3p in colorectal cancer, is a potential prognostic factor for colorectal cancer.
最近，强烈暗示与癌症发生有关的 microRNAs（miRNA）改变了我们对非蛋白编码 RNA 作用的理解。在这里，我们专注于 miR-202-3p 的功能和分子机制及其在结直肠癌中的潜在临床应用。
通过定量逆转录 PCR（qRT-PCR）在 94 例结直肠癌组织和相应的非癌组织（NCT）中确定 miR-202-3p 的表达。体外细胞增殖和集落形成实验以及体内异种移植实验用于评估 miR-202-3p 对结直肠癌细胞增殖的影响。荧光素酶测定和 Western blot 分析用于通过在线预测和微阵列分析进行初步筛选后验证 miR-202-3p 的潜在靶标。通过 qRT-PCR 和免疫组织化学染色检测靶基因的 mRNA 和蛋白水平。通过定量 PCR 测量前 miR-202 的拷贝数。
首先，与 NCT 相比，miR-202-3p 在 46.7%的结直肠癌样本中明显下调。miR-202-3p 的过表达抑制结直肠癌细胞的体外生长并抑制裸鼠的肿瘤发生。然后，miR-202-3p 通过结合其 3'非翻译区下调 ADP-核糖基化因子样 5A（ARL5A）蛋白水平，并且敲低 ARL5A 可模拟 miR-202-3p 的增殖抑制作用。此外，与 NCT 相比，结直肠癌样本中 ARL5A 的 mRNA 和蛋白水平均上调，并且高 ARL5A 蛋白水平预示着结直肠癌的预后不良。
miR-202-3p 可能在结直肠癌中作为肿瘤抑制因子发挥作用，并且 ARL5A 是结直肠癌中 miR-202-3p 的功能靶标，是结直肠癌的潜在预后因素。
