lncRNA-NCAT1促进鼻咽癌转移的作用和分子机制研究

Distant metastasis accounts for 70% of treatment failure after definitive radiotherapy of nasopharyngeal carcinoma (NPC). It is acknowledged that long non-coding RNA (lncRNA) plays an important role in tumor metastasis. Our previous microarray analysis of NPC tumor tissue and normal nasopharyngeal epithelial tissue identified a high expression of lncRNA-NCAT1 in NPC. Further studies showed that: ①NCAT1 was significantly upregulated in NPC tissue samples and cell lines, and knocking-down of NCAT1 expression can inhibit NPC cell migration and invasion. RNA pulldown-mass spectrometry assay showed that NCAT1 could bind with RACK1 protein, and the latter has been reported to promote metastasis of NPC by activating downstream genes and signaling pathways. ②In 116 clinical tumor samples, we observed that distant metastasis-free survival and overall survival of patients with high NCAT1 expression were significantly worse than those with low NCAT1 expression. In this context, we proposed the hypothesis that NCAT1 promotes the metastasis of NPC by regulating downstream genes and signaling pathways through binding RACK1, and can act as molecular biomarker to predict metastasis and prognosis to guide individualized treatment. The following researches are going to be carried out: ①studying the function and molecular mechanism of NCAT1 in NPC metastasis by in vitro and in vivo functional experiments, and exploring and verifying the downstream targeted genes of RACK1; ②expand the sample size and test the expression level of NCAT1 to evaluate the predictive value of NCAT1 in NPC metastasis and prognosis. Through implementation of this project, it could provide new targets for the treatment of NPC, and further guide clinical selection of high-risk patients for individual treatment.

远处转移是鼻咽癌治疗失败的主要原因（占70%），lncRNA被证实在肿瘤转移中起重要作用。我们对鼻咽癌和正常鼻咽上皮组织进行芯片检测发现lncRNA-NCAT1在鼻咽癌中表达显著升高。进一步研究提示：①干扰NCAT1表达可抑制鼻咽癌细胞体外迁移和侵袭；RNA pulldown-质谱分析发现NCAT1与RACK1蛋白结合，后者被报道可通过激活下游基因和信号通路促进鼻咽癌转移；②NCAT1高表达患者无远处转移生存和总生存明显差于低表达患者。我们推测：NCAT1通过结合RACK1调控下游基因和信号通路促进鼻咽癌转移，并可作为预测转移的分子指标，指导个体化治疗。本课题拟：①通过体内外功能实验及RACK1下游靶点的探索与验证，阐明NCAT1促进鼻咽癌远处转移的作用及分子机制；②扩大样本量，检测鼻咽癌组织中NCAT1表达水平，明确其对鼻咽癌远处转移的预测价值；为发现新靶点和实现个体化治疗提供新思路。

远处转移是鼻咽癌治疗失败的主要原因（占70%），lncRNA被证实在肿瘤转移中起重要作用。然而，本项目因芯片筛选的lncRNA-NCAT1（LOC107985932）与新注释编码基因CD8B2的最后一个外显子的序列高度重叠，难以特异性地针对NCAT1开展进一步研究；因此重新选择在鼻咽癌中显著高表达的lncRNA-JPX和组成m6A甲基化转移酶复合物的关键基因之一WTAP继续研究。.通过本项目开展，我们发现lncRNA-JPX在鼻咽癌中表达水平显著升高，与患者不良预后密切相关；lncRNA-JPX可能与IGF2BP家族蛋白及YBX1结合，影响鼻咽癌细胞迁移参与鼻咽癌转移的调控。WTAP在鼻咽癌异常高表达，与患者不良预后密切相关；WTAP通过介导lncRNA DIAPH1-AS1的m6A甲基化修饰维持DIAPH1-AS1转录本的稳定性，而DIAPH1-AS1作为蛋白分子支架招募MTDH与LASP1结合，MTDH通过与促癌蛋白LASP1结合维持LASP1的稳定性，从而促进鼻咽癌的增殖和转移。研究结果能够为寻为筛选不同转移风险患者提供有效的分子指标，指导“个体化”治疗决策；并为寻找新的鼻咽癌精准治疗干预靶点提供思路。.修改研究方向后完成了申请书承诺的预期成果，发表SCI论文2篇，IF均大于10；协助培养研究生2名。