CBIO-38: CHARACTERISTICS OF microRNA EXPRESSIONS IN GLIOBLASTOMA WITH LEPTOMENINGEAL DISSEMINATION OR METASTASIS

BACKGROUND: Recurrent glioblastomas (GBMs) occasionally appear as disseminated or metastatic lesions at sites distant from the primary tumor, and clinical course of these GBMs is miserable. MicroRNAs (miRs) are small, noncoding RNAs, which regulate gene expression and various biological cellular events. The aim of this study is to clarify the miRs which promote dissemination or metastasis in GBMs. METHODS: Twenty-two supratentorial GBMs with leptomeningeal dissemination or metastasis to spinal cord or medulla oblongata (GBM with D/M) and 53 GBMs without D/M were analyzed. The expression levels of twenty-two miRs, which were known to be related to GBM, were examined using TaqMan real-time RT-PCR. After then, several miRs which were significantly upregulated or downregulated in GBMs with D/M were biologically examined by WST assay and migration assay, etc. RESULTS: Eight miRs (miR-7, -29b, -34a, -101, -124, -128a, -137, -218) were statistically decreased in GBM with D/M as compared with that without D/M. On the other hand, no miR was statistically increased in GBM with D/M. We focused on three miRs (miR-29b, miR-34a, and miR-101) that were most significantly decreased in GBM with D/M. Applying the mimic RNA for these miRs inhibited cell proliferation in WST assay and inhibited migration in migration assay in U87 and A172 glioma cells. In contrast, inhibitor of these miRs promoted cell migration in glioma cells. CONCLUSION: Expressions of several miRs (miR-29b, miR-34a, and miR-101) are characteristics in GBM with D/M. These miRs may be a predictive marker of dissemination or metastasis in GBMs.