Temozolomide-Mediated Gene and microRNA Expression Networks in the Inhibition of Glioblastoma Multiforme Formation by High Through-Put Sequencing Analysis

Glioblastoma multiforme, which belongs to high-grade gliomas, is the most common and serious primary gliomas in adults. Malignant gliomas are highly mobile, invasive, and difficult to completely resect through surgery. Therefore, radiation and chemotherapy generally follow surgical treatment as adjuvant therapies. Temozolomide, which is able to penetrate the blood-brain barrier, is an alkylating agent of the imidazotetrazine series and the major chemotherapeutic drug in the clinical treatment of malignant gliomas. However, the drug resistance of temozolomide decreases the therapeutic effects on the patients. Besides, the course of temozolomide treatment will last a lifetime which may cause a financial burden. Therefore, to further understand the temozolomide-mediated molecular mechanisms may enhance the efficacy and application of temozolomide in clinical therapy of glioblastoma. MicroRNAs comprise a novel class of endogenous, small, non-coding RNAs. MicroRNAs control gene expressions by targeting their target genes for degradation and/or translational repression. Several microRNAs have recently been shown to be definitely linked to glioblastoma, like miR-181 and miR-21. However, the roles and functions of these microRNAs in the glioblastoma formation are still unclear. Moreover, it’s also no studies to extensively analyze the temozolomide-regulated microRNA expressions involved in inhibiting glioblastoma cell proliferation. The overall specific aims are to better characterize the temozolomide-mediated gene and microRNA expression networks on glioblastoma development. We will use the high-throughput sequencing analysis to comprehensively investigate the temozolomide-regulated signaling pathways in glioblastoma formation. We will also identify the novel direct target genes regulated by temozolomide-influenced unknown microRNAs. Then, we will investigate the relationship among the temozolomide toxicity, unknown microRNA expressions, target gene effects and glioblastoma development. Finally, the synergistic effects with the temozolomide and unknown microRNAs combined therapy in glioblastoma will also be investigated. We suppose to detect- (1) By using next generation sequencing, we will get the temozolomide-regulated gene and microRNA profiles from temozolomide-treated U87 MG cells. (2) By using bioinformatic softwares, we will study and identify the role of temozolomide-regulated genes and microRNAs in different signaling pathways involved in glioblastoma formation. (3) We will explore and validate the novel target genes of unknown microRNAs. We will also identify the relationship among the temozolomide, unknown microRNAs, target genes and glioblastoma development. (4) By using the xenograft aninal model, we will investigate the effect of temozolomide and unknown microRNAs combined therapy in vivo. We will also study the temozolomide-microRNAs-mediated molecular mechanisms in glioblastoma development in vivo. The present proposal is an innovative study in researching temozolomide-mediated gene and microRNA regulations in Glioblastoma development. The results will not only provide a better insight to temozolomide -regulated pathways but also new directions for clinical application in glioblastoma multiforme therapy. It will also provide a strategy for development of new chemotherapeutic combination of microRNAs and temozolomide clinically. We expect this new way can raise the survival rate of the patients with brain tumor.