[1031] The miR-17-92 Cluster Is Overexpressed and Has an Oncogenic Effect on Renal Cell Carcinoma

Y Youssef, NM White, M Mankaruos, TF Chow, A Girgis, S Metias, J Honey, R Stewart, KT Pace, S Mossad, MY Gabril, GM Yousef. St. Michael's Hospital, Toronto, ON, Canada; London Health Sciences Centre, London, ON, Canada; St. Michael's Hospital, Toronto, Canada

Background: MicroRNAs (miRNAs) are small non-protein coding RNAs that are differentially expressed in many malignancies. We have previously identified 80 miRNAs that are dysregulated in ccRCC. The purpose of this study was to validate the overexpression of the miR-17-92 cluster in clear cell renal cell carcinoma (ccRCC), and test the effect of two members of this cluster (miR-17-5p and miR-20a) on tumor proliferation. In addition, we also aim to elucidate the role of miRNAs in ccRCC pathogenesis through bioinformatics analysis.
Design: miRNA expression was validated by qRT-PCR. Cell proliferation effects of miR-17-5p and miR-20a were tested in the ACHN renal adenocarcinoma cell line model. Cells were transfected with the miR precursor molecules, miR inhibitors, and appropriate controls. Also, indepth in-silico analyses were performed on the dysregulated miRNAs.
Results: Transfection of miR-20a inhibitor significantly reduced cell proliferation in a dose dependent manner. Transfection of miR-17-5p, which is not endogenously expressed in the ACHN cell line, lead to increased cell proliferation compared to control, and this effect was suppressed by miR-17-5p inhibitor. Bioinformatics analyses identified ten clusters of miRNAs dysregulated in ccRCC that followed the same expression patterns. We also identified matching patterns between reported chromosomal aberration in ccRCC and miRNA dysregulation for 37.5% of the miRNAs. Target prediction analyses identified many key molecules in ccRCC pathogenesis including HIFs, mTOR, VEGF and VHL were found to be potential targets for dysregulated miRNAs. A significant number of dysregulated proteins in ccRCC are potential miRNA targets. Also, many of the ccRCC-dysregulated miRNAs were found to be phylogenetically conserved.
Conclusions: Our data strongly supports that the members of the miR-17-92 cluster, which is found to be overexpressed in ccRCC, have an oncogenic effect on kidney cancer cell growth and they may do so through mediating the expression of known key molecules in ccRCC pathogenesis.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 11:45 AM

Platform Session: Section A, Monday Morning


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