环状RNA具有高度的特异性和稳定性，是实现RNA表观遗传调控的重要因子，其在肿瘤放射治疗抵抗中的作用和调控机制研究甚少。申请人报道了独特的天冬酰胺内肽酶（AEP）是肿瘤发生发展的重要促癌基因，且该酶在胶质母细胞瘤（GBM）中高表达，与预后密切相关。深入研究发现GBM中环状AEP(circ_0033009)，其上游受EGFR-STAT4调控；下游通过竞争结合miR-495-3p上调AEP表达；同时促进AEP入核，酶切失活野生型P53，导致GBM细胞对放射治疗抵抗；敲低circ_0033009后，GBM细胞的放射敏感性显著增强。据此，本项目拟借助分子、细胞和动物多途径，阐明此环状AEP（circ_0033009)结合特定miRNA和促进入核这两种高效、精准的调控作用，揭示其改变GBM放射治疗抵抗的可能机制。对该环状AEP靶点的干预，将可能为胶质母细胞瘤等的放射治疗提供新的策略和效果。

Circular RNA characterized by highly specific and stable is an important factor to regulated RNA epigenetically. Due to its novelty, the pathological functions and regulation in radioresistance are poorly known. The applicant found a unique asparagine endopeptidase (AEP) which promotes oncogenesis and progression.More, AEP was highly expressed in glioblastoma (GBM), and closely related to poor prognosis. Further studies found that a circular AEP (circ_0033009), regulated by EGFR-STAT4 signaling, mediated radioresistance in GBM. The underlying molecular mechnisms include: 1) competitive binding with miR-495-3p to enhance the expression of AEP in GBM; 2) promoting the nuclear import of AEP protein and cleavage of wild-type P53. The radiosensitivity of GBM cells with circ_0033009 knockdown was significantly enhanced. Accordingly, we plan to elucidate the two efficient and precise regulatory roles of circular AEP (circ_0033009) which are binding to specific miRNA and promoting nuclear localization of AEP protein, and reveal the new mechanism of radioresistance in GBM through molecular, cellular and animal studies. The intervention of the circular AEP will provide a new strategy and effect for the radiotherapy of tumors including GBM.