Circulating microRNAs as Biomarkers for Pediatric Astrocytomas

Since MicroRNAs (miRNAs) are potent regulators of gene expression, their expression and function alterations are associated with different types of cancer, including pediatric astrocytoma. Since the secretion of miRNAs by tumors into corporal fluids has made it possible to identify biomarkers in cancer, their deter mination in pediatric astrocytoma is vital. In order to gain insight into the mechanisms controlled by miRNAs in these neoplasms, we tested the expression of miRNAs 130a, 145, 335, 1303, and let-7g-3p by qPCR in tumors and blood serum from pediatric patients with astrocytoma. The data was analyzed with the DIANA-miRPath v3.0 platform. The data represented expression changes of all mirRNAs tested in both tumors and blood serum, which strongly suggest their use as circulating biomarkers for astrocytic tumors. The bioinformatic analysis -with DIANA-miRPath v3.0- showed the involvement of these miRNAs in extracellular matrix (ECM)-receptor interaction and proteoglycans in cancer, which control many hallmarks of cancer. In fact, the expression of the proteoglycan syndecan 4 (SDC4) and that of its biosynthetic enzymes, Exostosin Glycosyltransferase 1 (EXT1) and Xylosyltransferase 1 (XYLT1), were altered in pediatric astrocytoma. Our results highlight the role of microRNAs in the biology of pediatric astrocytoma and demonstrated for the first time the potential use of some circulating microRNAs as non-invasive biomarkers for this type of tumors, particularly miRs 130a, 145, and 335.