DUSP4正反馈调控MYCN促进神经母细胞瘤侵袭转移的作用及机制研究

Neuroblastoma (NB) is one of the children malignant solid tumors with worst prognosis. MYCN amplification is directly related to the prognosis of NB. However, MYCN itself is difficult to be used as therapeutic target. Therefore, to improve the prognosis of high-risk NB patients, it is of great significance to analyze the mechanism of MYCN-related malignant progression and to find new interventional targets. DUSP4, identified through the gene expression profile of large-scale NB samples, was found highly expressed in MYCN-amplified NB. Further analysis showed that the expression of DUSP4 was positively correlated with MYCN and significantly related to the overall survival of NB patients. Furthermore, our previous experiments showed that DUSP4 regulated MYCN expression through a positive feedback. GSEA analysis and functional experiments showed that DUSP4 can promote invasion and metastasis of MYCN-related NB cells by regulating the matrix protease and integrin signaling pathways. This project intends to analyze the clinical significance of DUSP4 in NB; to illuminate that DUSP4 promote the invasion and metastasis of MYCN-associated NB and to elucidate its mechanism; to demonstrate the molecular mechanism of the positive feedback regulation between MYCN and DUSP4. This project will deepen the understanding of the molecular mechanism of MYCN-related tumorigenesis of high-risk NB and provide new prognostic factors and potential interventional targets for clinical treatment of high-risk NB.

神经母细胞瘤（NB）是预后最差的儿童恶性实体肿瘤之一。MYCN的扩增与NB的预后直接相关，但MYCN本身难以作为药物治疗靶点，因此解析MYCN相关NB恶性发展的机制，寻找新的干预靶点，对改善高危NB患者预后至关重要。DUSP4是我们通过大规模临床样品筛选发现高表达于MYCN扩增型NB中的基因。分析发现，DUSP4的表达与MYCN高度正相关，且与NB患者长期生存率显著相关。初步证明MYCN和DUSP4之间存在正反馈调节。通过GSEA分析和功能实验发现DUSP4可通过调控基质蛋白酶和整合素信号，促进MYCN相关NB细胞的侵袭转移。本项目拟进一步分析DUSP4在NB中的临床意义；明确DUSP4促进MYCN相关NB侵袭转移的功能，并阐明其机制；论证MYCN和DUSP4之间的正反馈调控机制。本项目将深化对MYCN相关高危NB发生发展机制的认识，为高危NB的临床治疗提供新的预后指标和潜在干预靶点。

神经母细胞瘤（NB）是预后最差的儿童恶性实体肿瘤之一。MYCN的扩增与NB的预后直接相关，但MYCN本身难以作为药物治疗靶点，因此解析MYCN相关NB恶性发展的机制，寻找新的干预靶点，对改善高危NB患者预后至关重要。我们通过神经母细胞瘤临床样本分析发现，DUSP4在MYCN扩增型NB中高表达，且与NB患者不良预后显著相关。体外和体内功能实验均证实DUSP4促进了神经母细胞瘤的侵袭转移能力，通过RNAseq和蛋白质谱的方法阐明了DUSP4对肿瘤胞外基质信号和整合素信号相关分子的调控。进一步的机制发现MYCN和DUSP4两者之间存在正反馈调控作用，即MYCN可以直接结合DUSP4启动子区域，激活DUSP4基因的转录。而DUSP4则影响了MYCN的磷酸化进而调控MYCN蛋白的稳定性。我们的结果首次证明了DUSP4在神经母细胞瘤中作为癌基因促进了神经母细胞瘤的发生发展。迄今为止DUSP4与MYCN之间的调控关系还未见文献报道，我们的发现扩充了DUSP4和MYCN的分子调控网络，可能为高危神经母细胞瘤临床诊断和治疗提供新的预后指标和潜在干预靶点。