Differential expression of microRNAs in postoperative radiotherapy sensitive and resistant patients with glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most malignant primary brain tumor and more resistant to radiotherapy. However, hetero-radiosensitivity occurs in different patients. MicroRNAs (miRNAs) play important roles in the initiation and progression of a multitude of tumors. The study aims to examine the different microRNAs expression profiles of postoperative radiotherapy sensitive and resistant patients with GBM, to make an inquiry about their potential role and discover a certain set of radio-sensitivity markers. Three paired samples from six GBM patients who had only been treated with postoperative radiotherapy were selected, and then, they were divided into radiotherapy sensitive group and resistant group according to their overall survivals, local recurrence rates, and Karnofsky Performance Scale scores. Expression profiles of miRNAs in these two groups were determined by the method of microarray assay. Comparing with resistant patients, 13 miRNAs were significantly upregulated and 10 miRNAs were greatly downregulated in sensitive group. Among them, four miRNAs were validated by quantitative RT-PCR. The differentially expressed miRNAs and their putative target genes were revealed by bioformatic analysis to play a role in cell signaling, proliferation, aging, and death. High-enrichment pathway analysis identified that some classical pathways participated in numerous metabolic processes, especially in cell cycle regulation, such as mTOR, MAPK, TGF-beta, and PI3K-Akt signaling pathways. Our research will contribute to identifying clinical diagnostic markers and therapeutic targets in the treatment of GBM by postoperative radiotherapy.