鼻咽癌3号染色体中新型抑癌基因的鉴定与功能研究

项目名称： 鼻咽癌3号染色体中新型抑癌基因的鉴定与功能研究

项目编号： No.81202135

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 肿瘤学2

项目作者： 杜紫明

作者单位： 中山大学

项目金额： 24万元

中文摘要： 抑癌基因(TSGs)的启动子甲基化失活在肿瘤发生发展过程中起着非常重要的作用，而人类3号染色体中存在着大量的候选TSGs。我们先期利用针对3号染色体的NotI芯片技术筛选出10个鼻咽癌(NPC)特异性的候选TSGs，其中通过bisulfite测序发现NPC组织中WNT7a基因启动子区域和ITGA9基因第一内含子区域CpG岛存在甲基化，而且其在NPC组织中的表达也下调。提示WNT7a和ITGA9的失活在NPC发生发展过程起着重要作用。本研究拟继续在NPC细胞中过表达WNT7a和ITGA9，并观察过表达后细胞生长指数、细胞增殖和凋亡、浸润和转移、克隆形成能力等体外成瘤性，以及体内裸鼠致瘤能力等，以阐明其在NPC中的功能及分子信号通路；拟分别利用甲基化特异性PCR（MSP）和免疫组化技术检测WNT7a和ITGA9在NPC组织中甲基化状态及表达情况，并评估其作为NPC患者早期诊断、预后判断的价值。

中文关键词： 鼻咽癌；抑癌基因；ITGA9；甲基化特异性PCR；早期诊断

英文摘要： Epigenetic silencing of tumor suppressor genes (TSGs) by promoter methylation is an early event in the multi-step process of carcinogenesis. Human chromosome 3 (Chr. 3) contains clusters of TSGs involved in many cancer types including nasopharyngeal carcinoma (NPC). Using Not I Chr. 3 microarray, ten candidate TSGs were found in NPC. Among them, the CpG islands in the promoter region of WNT7a (Wingless-type Mouse mammary tumor virus integration site family, member 7A) and in the intron 1 region of ITGA9 (Integrin α9) were confirmed to be hypermethylated in NPC by bisulfite sequencing. Furthermore, WNT7a and ITGA9 were downregulated in NPC clinical samples as shown by Q-PCR and immunostaining. As WNT7a and ITGA9 execute significant functions related to the tumor cell biology, it is very important to clarify their function in NPC. In the present study, we will overexpress WNT7a and ITGA9 in NPC cell lines and observe the their influence on cell growth,cell proliferation,apoptosis, invasion and metastasis in vitro, as well as tumorigensis in vivo, to clarify the function and signaling pathways of these two genes in NPC. Methylation specific PCR (MSP) and immunstaining will be performed to detect the methylation status and expression pattern in NPC clinical samples, to evaluate their clinical application for early d

英文关键词： Nasopharyngeal Carcinoma；Tumor Suppressor Genes；ITGA9；Methylation Specific PCR；Early Diagnosis