title: MicroRNA-31 activates the RAS pathway and functions as an oncogenic MicroRNA in human colorectal cancer by repressing RAS p21 GTPase activating protein 1 (RASA1).
abstract: MicroRNAs (miRNAs) are known to play a vital role in colorectal cancer. We found a widespread disruption in miRNA expression during colorectal tumorigenesis using microarray and quantitative RT-PCR analysis; of the 161 miRNAs altered in colorectal cancer compared with normal adjacent tissue samples, miR-31 was the most significantly dysregulated. We identified candidate targets of miR-31 using bioinformatics approaches and validated RAS p21 GTPase activating protein 1 (RASA1) as a direct target. First, we found an inverse correlation between miR-31 and RASA1 protein levels in vivo. Second, in vitro evidence demonstrated that RASA1 expression was significantly decreased by treatment with pre-miR-31-LV, whereas anti-miR-31-LV treatment increased RASA1 protein levels. Third, a luciferase reporter assay confirmed that miR-31 directly recognizes a specific location within the 3'-untranslated region of RASA1 transcripts. Furthermore, the biological consequences of miR-31 targeting RASA1 were examined by the cell proliferation assay in vitro and by the immunodeficient mouse xenograft tumor model in vivo. Taken together, our results demonstrate for the first time that miR-31 plays a significant role in activating the RAS signaling pathway through the inhibition of RASA1 translation, thereby improving colorectal cancer cell growth and stimulating tumorigenesis.
authors: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, 22 Hankou Road, Nanjing 210093, PR China.
authors: Defang
authors: D
authors: Sun
authors: Feng
authors: F
authors: Yu
authors: Yutao
authors: Y
authors: Ma
authors: Ran
authors: R
authors: Zhao
authors: Xi
authors: X
authors: Chen
authors: Jie
authors: J
authors: Zhu
authors: Chen-Yu
authors: CY
authors: Zhang
authors: Jiangning
authors: J
authors: Chen
authors: Junfeng
authors: J
authors: Zhang
mesh_terms: D000818:Animals; D001483:Base Sequence; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016000:Cluster Analysis; D015179:Colorectal Neoplasms / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000378:metabolism* / Q000502:physiology*; D008969:Molecular Sequence Data; D009368:Neoplasm Transplantation; D020411:Oligonucleotide Array Sequence Analysis; D010957:Plasmids / Q000378:metabolism; D015398:Signal Transduction; D020729:p120 GTPase Activating Protein / Q000235:genetics / Q000378:metabolism*; D054462:p21-Activated Kinases / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism*
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C534612:MIRN31 microRNA, human; D035683:MicroRNAs; C539917:Mirn31 microRNA, mouse; C557248:RASA1 protein, human; C581321:RASA1 protein, mouse; D020729:p120 GTPase Activating Protein; C515905:Pak1 protein, mouse; D054462:p21-Activated Kinases; D018631:ras Proteins