title: Ectopic expression of miR-126*, an intronic product of the vascular endothelial EGF-like 7 gene, regulates prostein translation and invasiveness of prostate cancer LNCaP cells.
abstract: MicroRNAs (miRNAs) are endogenous noncoding RNAs that down-regulate gene expression by promoting cleavage or translational arrest of target mRNAs. While most miRNAs are transcribed from their own dedicated genes, some map to introns of 'host' transcripts, the biological significance of which remains unknown. Here, we show that prostate cells are naturally devoid of EGF-like domain 7 (Egfl7) transcripts and hence also deficient in a miRNA, miR-126*, generated from splicing and processing of its ninth intron. Use of recombinant and synthetic miRNAs or a specific antagomir established a role of miR-126* in silencing prostein in non-endothelial cells. We mapped two miR-126*-binding sites in the 3'UTR of the prostein mRNA required for translational repression. Transfection of synthetic miR-126* into prostate cancer LNCaP cells strongly reduced the translation of prostein. Interestingly, loss of prostein correlated with reduction of LNCaP cell migration and invasion. Thus, the robust expression of prostein protein in the prostate cells results from a combination of transcriptional activation of the prostein gene and absence of intronic miRNA-126* due to the prostate-specific repression of the Egfl7 gene. We conclude that intronic miRNAs from tissue-specific transcripts, or their natural absence, make cardinal contributions to cellular gene expression and phenotype. These findings also open the door to tissue-specific miRNA therapy.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd., Mobile, Alabama 36688-0002, USA.
authors.forename: Alla
authors.initials: A
authors.lastname: Musiyenko
authors.forename: Vira
authors.initials: V
authors.lastname: Bitko
authors.forename: Sailen
authors.initials: S
authors.lastname: Barik
mesh_terms: D020413:3' Untranslated Regions; D001483:Base Sequence; D045744:Cell Line, Tumor; D004730:Endothelium, Vascular / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D007438:Introns / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000235:genetics*; D009928:Organ Specificity; D011471:Prostatic Neoplasms / Q000473:pathology*; D014176:Protein Biosynthesis; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering
chemical_list: D020413:3' Untranslated Regions; C527111:MIRN126 microRNA, human; D008565:Membrane Proteins; D035683:MicroRNAs; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C422655:prostein