Abstract 5277: MicroRNA expression profile of astrocytoma in archived formalin-fixed paraffin-embedded brain tumor samples.

Abstract

Abstract Astrocytomas, a tumor derived from astrocytic glial cells, are the most common type of adult primary central nervous system (CNS) neoplasms, representing around 76% of all primary brain tumors. The World Health Organization (WHO) classified astrocytomas into four histological grades spanning from grade I, a benign tumor, to grade IV, a highly malignant tumors. This classification is somewhat subjective and more reliable molecular markers for tumor grading are necessary. MicroRNAs (miRNAs) are small (≈22-nucleotide) noncoding RNAs that, in mammals, regulate genes at the translational level by binding to loosely complimentary sequences in the 3’-UTR of target mRNAs. There is increased in vitro and in vivo evidence that various miRNAs are deregulated in a variety of cancer including astrocytoma. The aim of this study was to assess miRNAs dysregulated in astrocytoma according to its grade using archived formalin-fixed paraffin-embedded (FFPE) samples. Total RNA was isolated, labeled, and hybridized to Affymetrix miRNA arrays. Images were analyzed using the PARTEK software. Eighty-five miRNAs were differentially regulated in grade II, 72 miRNAs in grade III and 118 miRNAs in GBM; compared with control samples. Several non-previously described miRNA in astrcoytoma were identified in this study. The most differentially expressed miRNAs in each tumor grade, were selected for further validation by TAqMan-based real-time PCR. Particularly, miR-92b was upregulated in all astrocytoma grades. Opposite, miR-548p, a miRNA regulating antiapoptotic molecules, was downregulated in GBM tumor tissues, and in well-established GBM cell lines. However, the role of these miRNAs in GBM cells has not been studied. We are currently performing in vitro studies to clarify the role of some of these microRNAs in the cell proliferation of GBM cells. Citation Format: Mónica Rivera-Díaz, Mario Quintero, Julio López, P E. Vivas-Mejia. MicroRNA expression profile of astrocytoma in archived formalin-fixed paraffin-embedded brain tumor samples. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5277. doi:10.1158/1538-7445.AM2013-5277