Abstract

Abstract MicroRNAs (miRNAs) regulate mRNA stability and protein expression, and certain miRNAs have been demonstrated to act either as oncogenes or tumor suppressors. A potential role for miRNAs in malignancy has been suggested by the location of the genes for several miRNAs at sites of translocation breakpoints or deletions linked to a specific neoplastic state. Allelic deletion on chromosome 14q plays an important role in the pathogenesis of GBM and was thought to harbor multiple tumor suppressor genes associated with GBM, a region which also encodes mir-203. Real-time PCR and insitu hybridization showed decreased levels of mir203 expression in anaplastic astrocytoma and glioblastoma tissues and cell lines. Exogenous expression of mir-203 using a plasmid expressing mir-203 precursor (pmir-203) suppressed cell invasion and migration in SNB19 glioblastoma cell line and 4910 xenograft cells. We determined that one relevant target of miR-203 was ROBO1, since miR-203 expression decreased mRNA and protein levels as determined by RT-PCR and western blot analysis. Moreover, cotransfection experiments using luciferase-based transcription reporter assay have shown direct regulation of ROBO1 3α-UTR regions by miR-203 which was significantly abrogated when mutating the predicted miR-203 seed regions in the pMIR-REPORT UTR constructs, thereby validating the direct interaction between miR-203 and the ROBO1 3α-UTRs. Concordantly, over expressing ROBO1 expression construct with no mir-203 binding site blocked pmir-203 mediated suppression of migration and invasion. Taken together these studies demonstrate that up regulation of Robo1 in response to the decrease in mir-203 in glioma cells is responsible for glioma tumor cell migration and invasion. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5621. doi:1538-7445.AM2012-5621

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