Department of Neurosurgery, The First Hospital of China Medical University, No. 155 North Nanjing Street, Shenyang, 110001, China.
Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, China.
Cell Death Dis. 2023 Jan 13;14(1):23. doi: 10.1038/s41419-023-05556-y.
Glioma is the most aggressive and common malignant neoplasms in human brain tumors. Numerous studies have showed that glioma stem cells (GSCs)drive the malignant progression of gliomas. Recent studies have revealed that circRNAs can maintain stemness and promote malignant progression of glioma stem cells. We used bioinformatics analysis to identify circRNAs and potential RNA-binding proteins (RBPs) in glioma. qRT-PCR, western blotting, RNA FISH, RNA pull-down, RNA immunoprecipitation assay, ChIP, immunohistochemistry, and immunofluorescence methods were used to quantified the expression of circNCAPG, U2AF65, RREB1 and TGF-β1, and the underlying mechanisms between them. MTS, EDU, neurosphere formation, limiting dilution neurosphere formation and transwell assays examined the proliferation and invasive capability of GSCs, respectively. We identified a novel circRNA named circNCAPG was overexpressed and indicated the poor prognosis in glioma patients. Upregulating circNCAPG promoted the malignant progression of GSCs. RNA binding protein U2AF65 could stabilize circNCAPG by direct binding. Mechanically, circNCAPG interacted with and stabilized RREB1, as well as stimulated RREB1 nuclear translocation to activate TGF-β1 signaling pathway. Furthermore, RREB1 transcriptionally upregulated U2AF65 expression to improve the stability of circNCAPG in GSCs, which established a feedback loop involving U2AF65, circNCAPG and RREB1. Since circRNA is more stable than mRNA and can execute its function continuously, targeting circNCAPG in glioma may be a novel promising therapeutic.
神经胶质瘤是人类脑肿瘤中最具侵袭性和最常见的恶性肿瘤。大量研究表明，神经胶质瘤干细胞（GSCs）驱动神经胶质瘤的恶性进展。最近的研究表明，circRNAs 可以维持神经胶质瘤干细胞的干性并促进其恶性进展。我们使用生物信息学分析鉴定了神经胶质瘤中的 circRNAs 和潜在的 RNA 结合蛋白（RBPs）。qRT-PCR、western blot、RNA FISH、RNA 下拉、RNA 免疫沉淀检测、ChIP、免疫组化和免疫荧光方法用于定量检测 circNCAPG、U2AF65、RREB1 和 TGF-β1 的表达，并研究它们之间的潜在机制。MTS、EDU、神经球形成、有限稀释神经球形成和 Transwell 检测分别用于检测 GSCs 的增殖和侵袭能力。我们鉴定了一种新型 circRNA，命名为 circNCAPG，它在神经胶质瘤患者中过表达，并预示着不良预后。上调 circNCAPG 促进了 GSCs 的恶性进展。RNA 结合蛋白 U2AF65 可以通过直接结合来稳定 circNCAPG。机制上，circNCAPG 与 RREB1 相互作用并稳定其，同时刺激 RREB1 核转位以激活 TGF-β1 信号通路。此外，RREB1 转录上调 U2AF65 的表达，以提高 GSCs 中 circNCAPG 的稳定性，从而建立了涉及 U2AF65、circNCAPG 和 RREB1 的反馈环。由于 circRNA 比 mRNA 更稳定，可以持续发挥其功能，因此靶向神经胶质瘤中的 circNCAPG 可能是一种有前途的新型治疗方法。
