Revealing microRNAs in malignant progression of oligodendrogliomas

4^th World Congress on Cancer Science & Therapy

October 20-22, 2014 DoubleTree by Hilton Hotel Chicago-North Shore Conference Center, USA

Luciano Neder

Accepted Abstracts: J Cancer Sci Ther

Abstract :

MicroRNAs (miRNAs, miRs) are short non-coding regulatory RNA molecules found ubiquitously in living beings. Recently, miRNAs have also been implicated in oncogenesis, acting as tumor suppressors or oncogenes. Hitherto, the role of miRNAs in CNS tumors has been intensively investigated in glioblastomas and medulloblastomas, but there are few data regarding the role of miRNAs in oligodendrogliomas. We performed a systematic evaluation of miRNAs and mRNAs expressions in a series of oligodendrogliomas of different grades of malignancy to determine miRNAs and putative target genes that are differentially expressed in grade III oligodendrogliomas. Total RNA was extract from 14 cases of bona fide grade II and III oligodendrogliomas naïve of treatment (7 cases per grade) after tumor microdissection. For each case, the expression of miRNAs (100ng) and mRNAs (200ng) was evaluated using microarray-based expression profiling platforms (723 transcripts and 41,000 genes, respectively). Samples of temporal white matter from patients operated for epilepsy were used as controls (n = 15). The study was approved by Ethical Committee. Fifteen and 20 miRNAs were significantly over- and underexpressed in anaplastic oligodendrogliomas, respectively. However, after matching with the expressions of putative target-mRNAs disclosed by microarray, we were able to validate 8 out of 10 miRNAs by RT-qPCR (assays in duplicate). Among the hypo-expressed miRNAs, we found some miRs that were previously described in cell differentiation of embryonic stem cells (miR27a, miR-30a/ PDGFA and miR24/HDAC2) as well as miR193a-3p and miR30c/RARB. Conversely, among the hyper-expressed miRNAs, we validated the microarray data of miR301/BCL-2 and miR378/FGF2, and PPP4R4 and CD44. Nonetheless, we were able to identify and validate some oncogenic miRNAs and putative target-mRNAs that can be operating in malignant progression of oligodendrogliomas. The biological roles of these miRNAs are being addressed through functional assays in primary cell lines of gliomas.