SEMA3B、SEMA3F基因在鼻咽癌细胞中突变和表达的研究  

Mutation and Expression of SEMA3B and SEMA3F Gene in Nasopharyngeal Carcinoma

作　　者：刘晓琼[1] 孙敏[2] 陈汉奎[1] 李京湘[2] 潘志刚[1] 龙綮新[3] 王珣章[3] 曾益新[1] 

机构地区：[1]中山大学肿瘤防治中心研究所病理室,广东广州510060 [2]北京华大基因组研究中心,北京101300 [3]中山大学生物防治国家重点实验室生物医药中心,广东广州510275

出　　处：《癌症》2003年第1期16-20,共5页Chinese Journal of Cancer

基　　金：国家"973"项目(No.G1998051009);广东省科委重点项目(No.980950)

摘　　要：背景与目的:鼻咽癌(nasopharyngealcarcinoma,NPC)致病的分子机理至今仍不清楚,但高频的杂合性缺失和功能学证据均表明染色体3p21.3区段中存在着与鼻咽癌相关的抑癌基因。SEMA3B和SEMA3F基因是定位于3p21.3的两个semaphorin家族成员,最近被鉴定为抑癌基因。本研究通过对SEMA3B和SEMA3F基因在鼻咽癌中的突变和表达检测,探讨SEMA3B和SEMA3F基因与鼻咽癌发病的关系。方法:采用PCR-直接测序方法,在21例散发性NPC组织和2例NPC细胞株(CNE2,SUNE1)中对SEMA3B和SEMA3F基因的编码区、拼接位点和部分调控区进行突变检测;利用半定量RT-PCR方法,检测SEMA3B和SEMA3F基因在鼻咽癌中的表达。结果:在鼻咽癌中未发现SEMA3B或SEMA3F基因具有体细胞突变,但在SEMA3B基因中发现两个导致氨基酸改变的单核苷酸多态性Thr415Ile和Ile242Met。在Thr415Ile多态位点中,可导致SEMA3B基因功能缺陷的Ile等位基因频率在鼻咽癌患者中占有较高比例(64%,27/42)。SEMA3BmRNA在6例鼻咽非癌组织中正常表达,但在76%(16/21)的鼻咽癌组织中表达下调或缺失;SEMA3FmRNA的表达水平在鼻咽癌和非癌组织中无明显差异。结论:SEMA3BmRNA在鼻咽癌中发生高频表达缺失说明该基因失活与鼻咽癌密切相关,SEMA3B基因可能是定位于染色体3p21.BACKGROUND &OBJECTIVE:Thoug h the molecular etiolog y of nasopharyng eal carcinoma (NPC)is currently unknown,evidence from both loss of heterozyg osity analysis and functional studies sug g ested that there are NPC-associated tumor suppressor g e nes (TSGs )residing in chromosome 3p21.3.Recently,two members of sem aphorin family,SEMA3B and SEMA3F g ene,located at 3p21.3,were charac terized as TSGs.Studies showed that SEMA3B and SEMA3F are capable of suppressing the g rowt h of tumor cells and inducing apoptosis.Loss of SEMA3B mRNA expression or aberrant SEMA3F cellular localization were found in lung cancers.In order to investig at e the involvement of SEMA3B and SEMA3F in NPC,the authors examined both mutation and expression of these two g enes in NPC.METHODS :The entire coding reg ions ,the splice donor /acceptor sites,and partial reg ulator y reg ions of SEMA3B and SEMA3F g ene were screened for mutations by P CR-sequencing in 21primary NPC tumors and 2NPC cell lines (CNE2and SUNE1).The mRNA expression levels were determined b y semi-quantitative RT-PCR analysi s.RESULTS :No somatic mutation was found in eith er SEMA3B or SEMA3F g ene.However,two missense polymorphism s including Thr415Ile and Ile242Met were found in SEMA3B in NPC.For the Thr415Ile polymorphi sm,the Ile allele type which leads to SEMA3B function defects was predominant in NPC with the allele frequency of 64%(27/42).SEMA3B mRNA was expressed in all 6non-neoplastic nasopharyng eal epithel ia,but was absent or down-reg ulated in 76%(16/21)of primary NPC tumors.No sig nifican t difference of SEMA3B expression was observed between NPC and noncancerous controls.CONCLUSION:Hig h frequency of SEMA3B expression alterations sug g ests th at the inactivation of this g ene was strong ly associated with NPC.SEMA3B may be a tumor suppressor on 3p21.3involved in NPC.

关 键 词：SEMA3B基因 基因表达 基因突变 杂合性缺失 SEMA3F基因 鼻咽癌 

分 类 号：R739.63[医药卫生—肿瘤]