NUDT21抑制NFKBIZ近端ploy(A)位点激活NF-κB通路并形成正反馈回路介导胶质母细胞瘤间质转化的分子机制

Promoting glioma cell from proneural to mesenchymal transformation (PMT) via activation of NF-κB pathway is an important mechanism of malignant progression of glioblastoma (GBM). Previously we have reported that NUDT21, an RNA-terminal polyadenylation protein, promoted the PMT process in GBM (Front Mol Neurosci, 2017). Further preliminary experiments showed that NUDT21 inhibited ploy (A) proximal site and down-regulated the expression of NFKBIZ , following activating NF-κB pathway to promote GBM interstitial transformation. Meanwhile, RelA, a key transcription factor of NF-κB pathway, can positively regulate NUDT21 promoter activity. Based on the above mentioned results, by using the technology of 3'RACE, RIP, RNA-seq etc., we seek to elucidate the mechanisms regarding the activation of NF-κB signaling pathway by NUDT21-mediated regulation of the alternative polyadenylation of NFKBIZ in cells, animal models and clinical samples; to explore the molecular mechanism regarding the regulation of NUDT21 by RelA; to in-depth research on the possible formation of positive feedback loop formed by NUDT21 and NF-κB signaling pathway and the regulatory network for promoting the mesenchymal transformation of GBM, finally to investigate the feasibility of reversing PMT by targeting this loop, thus to provide a new clues for GBM treatments.

NF-κB通路的激活促进细胞间质型转化(PMT)是胶质母细胞瘤(GBM)恶性进展的重要机制。我们已证实RNA尾端多腺苷化修饰蛋白NUDT21促进GBM的PMT过程 (Front Mol Neurosci, 2017)，进一步预实验发现，NUDT21可抑制NFKBIZ近端ploy(A)位点而下调其表达，进而激活NF-κB通路，促进GBM间质转化；同时，NF-κB通路关键转录因子RelA可正向调控NUDT21启动子活性。在此基础上，本项目拟通过3'RACE、RIP及RNA-seq等技术，在细胞、动物模型及临床样本中，阐明NUDT21通过影响NFKBIZ可选择性多腺苷化位点激活NF-κB通路的分子机制，探究RelA转录调控NUDT21的分子机理；深入研究NUDT21与NF-κB通路形成正反馈回路的可能性及其促进GBM间质转化的调控网络，探讨靶向该回路逆转PMT的可行性，为GBM的治疗提供新思路。

胶质瘤是最常见的中枢神经系统原发性恶性肿瘤，其中恶性程度最高的胶质母细胞瘤（GBM）肿瘤生长迅速、手术难以完全切除、复发率高、患者预后极差。GBM的间质转化（PMT）是肿瘤恶性进展的重要机制。在本项目中，我们通过细胞实验、动物实验及临床样本证明NUDT21可以作用于NFKBIZ近端poly（A）位点而影响NF-κB通路的活化，从而调控GBM的间质转化及肿瘤的恶性进程；并且验证了miR-187-3p对NFKBIZ的调控作用以及RelA对NUDT21的调控作用。除此之外，在本课题经费的支持下，我们还进行了KLF4 通过调控 ITGB4表达影响胶质瘤干细胞的干性及SNRPG 影响胶质母细胞瘤替莫唑胺化疗敏感性等相关研究。我们所得到的实验结果为GBM发生发展及治疗提供了新的机制与靶点，有望为胶质瘤临床诊断与治疗提供新的策略。

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