title: An In Vivo Method to Identify microRNA Targets Not Predicted by Computation Algorithms: p21 Targeting by miR-92a in Cancer.
abstract: microRNA (miRNA) dysregulation is involved in the development and progression of various human cancers, including hepatocellular carcinoma (HCC). However, how to identify the miRNAs targeting specific mRNA in cells is a significant challenge because of the interaction complexity and the limited knowledge of rules governing these processes. Some miRNAs are not predictable by current computer algorithms available. Here, using p21 mRNA as target, we established a new method, called miRNA in vivo precipitation (miRIP), to identify which kind of miRNAs can actually bind to the specific mRNA in cells. Several unpredictable miRNAs that bound p21 mRNA in HepG2 and PC-3 cells were identified by the miRIP method. Among these miRNAs identified by miRIP, miR-92a was found and confirmed to interact robustly with p21 mRNA, both in HepG2 and PC-3 cells. miR-92a was found to be remarkably increased in HCC tissues, and higher expression of miR-92a significantly correlated with lower expression of p21, which is related to poor survival of HCC patients. Moreover, inhibition of miR-92a could significantly suppress HCC growth in vitro and in vivo by upregulating p21. Together, miR-92a, which is identified by miRIP, is functionally shown to be associated with HCC growth as an oncogenic miRNA by inhibiting expression of targeting gene p21. In addition, several unpredictable miRNAs that target STAT3 mRNA were also identified by the miRIP method in HepG2 cells. Our results demonstrated that the miRIP approach can effectively identify the unpredictable but intracellular existing miRNAs that target specific mRNA in vivo.
authors.affiliation: National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, P. R. China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Su
authors.affiliation: Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, P. R. China.
authors.forename: Huaming
authors.initials: H
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ge
authors.affiliation: National Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors.forename: Mingjin
authors.initials: M
authors.lastname: Yang
authors.affiliation: National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, P. R. China.
authors.forename: Jin
authors.initials: J
authors.lastname: Hou
authors.affiliation: National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, P. R. China.
authors.forename: Taoyong
authors.initials: T
authors.lastname: Chen
authors.affiliation: National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, P. R. China.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: National Key Laboratory of Medical Immunology and Institute of Immunology, Second Military Medical University, Shanghai, P. R. China. Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, P. R. China. National Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, P. R. China. caoxt@immunol.org.
authors.forename: Xuetao
authors.initials: X
authors.lastname: Cao
mesh_terms: D000465:Algorithms; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000401:mortality; D019295:Computational Biology / Q000379:methods / Q000592:standards; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D056726:Genetic Association Studies / Q000379:methods*; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000401:mortality; D008297:Male; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics* / Q000628:therapy*; D014407:Tumor Cells, Cultured
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D035683:MicroRNAs