IGFBP3调控鼻咽癌转移的作用及机制

Distant metastasis is the main cause of death in nasopharyngeal carcinoma (NPC), but the molecular mechanism of metastasis remains unknown. In current study, IGFBP3 was found to be down-regulated in highly metastatic NPC cells(S18 and 5-8F) and the metastatic tissues in lymph node compared to low metastastic NPC cells(S26 and 6-10B ) and the NPC primary tumor tissues. We found silencing IGFBP3 made EMT regulator Snail increasing. Further study found knocking down IGFBP3 promoted migration of NPC tumor cell. The methods including luciferase reporter assays, the point mutation and chromatin immunoprecipitation are performed to validate that the loss of IGFBP3 induced EMT of tumor cells by upregulating Snail, which promoted tumor cells metastasis. Finally, immunohistochemistry assay is used to detect and validate the relationship between IGFBP3 and Snail. Statistical analysis is used to assess the prognostic value of IGFBP3. The goal of current study is to further indentify the molecular mechanisms of NPC metastasis through IGFBP3/Snail signaling pathway and provide a new target for the diagnosis and treatment of NPC using cell biology, animal model, and clinic sample with long follow-up data.

远处转移是鼻咽癌患者的主要死因，其分子机制尚不明确。我们前期发现：胰岛素生长因子结合蛋白3（IGFBP3）在高转移鼻咽癌细胞株中低表达；对比鼻咽癌原发灶，转移淋巴结中IGFBP3蛋白表达降低；且初步结果提示IGFBP3可能直接调控Snail表达、上皮-间质转化（EMT）和鼻咽癌转移。本项目拟通过细胞和动物转移模型进一步证实IGFBP3抑制鼻咽癌转移的作用，并采用双荧光素酶报告基因、DNA定点突变和染色质免疫共沉淀等实验明确分子机制为：IGFBP3直接结合到Snail启动子抑制其表达，从而影响EMT，抑制鼻咽癌转移。最后，在鼻咽癌临床标本中采用免疫组化方法检测验证IGFBP3与Snail、EMT标志物的相关性，评估IGFBP3的预后预测价值。从而阐明IGFBP3在鼻咽癌转移中的作用、分子调控机制及临床意义。本项目的开展将有助于探明鼻咽癌转移的机制，为鼻咽癌提供新的肿瘤标志物和潜在的治疗靶点。

肿瘤转移和复发是鼻咽癌治疗失败和死亡的主要原因。目前为止，鼻咽癌转移和复发的具体机制尚不明确，因此鼻咽癌转移和复发机制的阐明及其防治具有重要的临床意义。.为探索鼻咽癌转移的分子机制，通过qPCR方法检测MORF4L1基因在鼻咽癌患者鼻咽原发灶组织和鼻咽癌高转移细胞株中低表达，敲低和过表达MORF4L1后，Western blot、CCK8、划痕、transwell实验等方法证实MORF4L1抑制鼻咽癌的增殖、侵袭和迁移。过表达MORF4L1同时敲低p21和E-cadherin，采用CCK8、划痕、transwell实验等方法明确MORF4L1通过调控p21和E-cadherin而发挥抑癌基因的功能。这为鼻咽癌的治疗提供了新的靶点。.为探究鼻咽癌复发的分子机制，分析公共基因芯片数据发现LCN2在放射抗拒细胞株CNE2R中表达较敏感细胞株CNE2中升高。通过shRNA敲低或基因克隆过表达LCN2后，克隆形成实验表明LCN2增加了鼻咽癌细胞的克隆形成能力。γH2AX实验显示LCN2增强了鼻咽癌细胞DNA损伤修复能力，导致鼻咽癌细胞放射抗拒。免疫组化分析表明鼻咽癌标本中LCN2表达与鼻咽癌放射抗拒和复发有关。Cox回归模型多因素分析提示LCN2表达是鼻咽癌复发的独立预后指标。组织微阵列结果显示LCN2表达与HIF1A表达相关。LCN2可能为鼻咽癌的一个新的预后指标和治疗靶点。.我们的研究结果为阐明鼻咽癌发生转移和复发的机制提供新的通路，为鼻咽癌提供新的肿瘤标志物和潜在治疗靶点。