鼻咽癌中炎症介质SNPs的预后价值及CXCL12介导远处转移的作用及机制研究

Distant metastasis is the major treatment failure of nasopharyngeal carcinoma (NPC).TNM staging alone can not accurately predict the distant metastasis-free survival rate . It is an urgent and important clinical issue to forecast as soon as possible the cases with high risk of metastasis and give appropriate treatments. Recent studies have indicated that inflammatory mediator SNPs can be used as biomarkers to predict distant metastasis, Our preliminary experiments shows that: ①Inflammatory mediator IL-8 rs4073 and CXCL12 rs1801157 significantly correlates with PFS and distant metastasis in nasopharyngeal carcinoma, ②A allele of CXCL12 rs1801157 up regulates gene expression, ③CXCL12 enhances the migration and ivasion of NPC cells. In this study, we will retrospectively collect large samples of genomic DNA and clinical data of NPC patients and genotype to clarify the prediction role of IL-8 rs4073 and CXCL12 rs1801157 in metastasis and prognosis of NPC. Furthermore, we will do experimental studies in vitro and in vivo to elucidate the role and mechanism of CXCL12 in metastasis of NPC, and verify the correlation of the expression and clinical prognosis in paraffin specimen. Through this research implementation, it could provide predictive biomarkers for metastasis and new targets for individual therapy in patients with NPC.

远处转移是鼻咽癌治疗失败的主要模式，单纯TNM分期不能准确预测预后。寻找分子指标来预测高转移风险病例并给予恰当治疗是临床急需解决的重要问题。近年发现炎症介质SNPs可作为预测肿瘤转移的分子指标。我们的前期实验结果初步发现：①炎症介质IL-8 rs4073、CXCL12 rs1801157基因多态性与鼻咽癌患者无进展生存及远处转移呈显著相关；②CXCL12 rs1801157位点A等位基因能上调基因表达水平；③CXCL12能诱导鼻咽癌细胞的迁移、侵袭。在此基础上，本课题拟继续开展：①大样本量明确IL-8 rs4073、 CXCL12 rs1801157在预测预后及远处转移的作用；②阐明 CXCL12在鼻咽癌远处转移中的生物学功能及调控机制，并在临床标本中验证其表达及与预后的关系。拟通过本项目的研究，为鼻咽癌的分子分型和"个体化"治疗提供指导，并为鼻咽癌治疗提供新靶点奠定基础。

远处转移是鼻咽癌治疗失败的主要模式，单纯TNM 分期不能准确预测预后。寻找分子指标来预测高转移风险病例并给予恰当治疗是临床急需解决的重要问题。近年发现炎症介质的单核苷酸多态性(SNPs)可作为预测肿瘤转移的分子指标，而目前国内外尚无有关炎症介质SNPs与鼻咽癌发展及预后评估的研究报道。本课题将明确炎症介质SNPs在鼻咽癌预后评估中的价值。我们选择炎症介质相关的4个基因6个SNP位点（包括IL-8 rs4073、CXCR4 rs2228014、CXCL12 rs1801157、TNF-a rs1799724、TNF-a rs1799964、TNF-a rs1800630），利用直接测序法检测了222例鼻咽癌外周血DNA的上述6个SNP位点，与临床预后资料结合进行生存分析。单因素分析结果发现CXCL12 rs1801157位点多态性与鼻咽癌患者无远处转移生存及无进展生存显著相关，CXCL12 rs1801157位点AA基因型患者的无远处转移生存和无进展生存显著差于GG+AG基因型患者(P=0.013和P=0.021)。多因素分析显示CXCL12 rs1801157是影响无远处转移生存(hazard ratio: 3.332, 95% CI: 1.597-6.949; P=0.001)和无进展生存(hazard ratio: 2.665, 95% CI: 1.387-5.119; P=0.003)的独立预后因素。为了进一步明确CXCL12 rs1801157不同基因型的生物学功能，我们采用双荧光素酶报告基因系统，构建含不同基因型的含荧光素酶基因的表达载体，转染后观察对荧光素酶活性的影响。我们发现pGL3-A 的荧光素酶活性显著高于pGL3-T，提示CXCL12 rs1801157的A等位基因能上调基因转录，使其表达改变。上述实验间接证明了CXCL12 rs1801157的不同基因型能改变基因表达水平。我们利用划痕实验和Transwell小室侵袭实验，发现CXCL12可诱导鼻咽癌细胞的迁移和侵袭。因此，我们的研究结果证实了CXCL12 rs1801157位点的多态性与鼻咽癌患者的预后相关，CXCL12 rs1801157中A等位基因能上调基因表达水平，CXCL12可诱导鼻咽癌细胞的迁移和侵袭。这将为鼻咽癌的分子分型和“个体化”治疗提供指导，并可能为鼻咽癌的治疗提供新的靶点。