摘要
目的检测大肠癌及其转移淋巴结中β-连接素(β-catenin,β-cat)蛋白及mRNA表达,讨论β-catenin的表达与大肠癌生物学行为的关系,为针对大肠癌诊断和治疗的可能新方法提供理论依据.方法采用免疫组织化学染色,蛋白免疫印记(Western Blot),逆转录-多聚合酶链反应(RT-PCR)等方法联合检测并比较45例大肠癌患者原发灶和转移淋巴结中β-catenin表达情况,并对其在转移淋巴结内癌细胞再表达的机理进行分析.结果β-cat在转移淋巴结癌细胞中的再表达与肿瘤细胞的分化程度、组织学类型密切相关.(1)免疫组化结果显示:在45例大肠癌原发灶中80%(36/45)β-cat不正常表达,40%(18/45)大肠癌转移淋巴结中β-cat再表达阳性.其中高中分化腺癌转移淋巴结内癌细胞β-cat再表达阳性率为54.2%(13/24),而低分化腺癌为23.8%(5/21),高中分化腺癌相对于低分化癌更易出现β-catenin的再表达阳性(P<0.05);在管状及乳头状腺癌β-catenin在转移淋巴结癌细胞中的再表达阳性率为35.7%(10/28),而在粘液腺癌则为47.1%(8/17,P<0.05).β-cat在转移淋巴结内癌细胞的再表达与肿瘤部位、浸润深度以及患者的性别和年龄无关;(2)RT-PCR结果显示,45例原发灶组织及相应转移淋巴结均检测到不同程度的β-cat基因表达.β-catmRNA在大肠癌的表达量为(0.724±0.006),明显低于正常大肠粘膜表达量(0.785±0.017,t=21.066,P<0.01);β-catmRNA在大肠癌转移淋巴结表达量明显高于大肠癌原发灶表达量,但低于正常大肠粘膜表达量;结合临床病理资料分析,高中分化大肠癌转移淋巴结中β-cat mRNA表达量高于低分化大肠癌转移淋巴结,管状腺癌转移淋巴结中β-cat mRNA表达量高于粘液腺癌转移淋巴结;(3)Western Blot结果显示:与25例均表达β-cat的正常大肠粘膜相比,45例原发肿瘤组织中41例检测到不同程度的β-cat表达,4例未表达:41例表达β-cat的原发肿瘤组织中其相应转移淋巴结中均检测到不同程度的β-cat蛋白表达,而4例未表达β-cat的原发肿瘤组织中有1例在其转移淋巴结中发现了β-cat的表达;这41例原发灶组织中各例蛋白相对强度分布区间为6～108(54.3±38.1),明显低于正常大肠粘膜蛋白表达量15～172(95.4±49.8),β-cat在大肠癌转移淋巴结蛋白表达量明显高于大肠癌原发灶蛋白表达量,但低于正常大肠粘膜蛋白表达量;结合临床病理资料分析,转移淋巴结中,高中分化大肠癌转移淋巴结中β-cat蛋白表达量高于低分化大肠癌转移淋巴结,管状腺癌转移淋巴结中β-cat蛋白表达量高于粘液腺癌转移淋巴结.结论大肠癌发生发展过程中β-cat在基因及蛋白水平的表达存在一定的变化特征,这种特征使其有可能成为大肠癌诊断与治疗的新靶点.
Objective To investigate the expression of β-catenin mRNA and protein in hunman advanced colorectal cancer and their metastatic lymph nodes,discuss the correlation between the expression of β-catenin and the biological behaviour of colorectal cancer,and explore a new possible target on molecular level to diagnose and treat colorectal cancer.Methods The methods of immunohistochemical staining,semiquantitative RT-PCR and western blot were used to detect and compare the expressions of β-cat mRNA and protein in 45 cases of human advanced colorectal cancer and their metastatic lymph nodes.And the mechanism by wich β-cat reexpress in metastatic lymph nodes of colorectal cancer was explored.Results The re-expression level of β-cat in metastatic lymph nodes was closely related to the differentiating degree and histological type of tumor.（1） Immunohistochemical results：the abnormal expression rate of β-cat was 80%（36/45） in 45 primary tumors of human advanced colorectal cancers,and the re-expression rate of β-cat in metastatic lymph nodes was 40%（18/45） .The re-expression rate ofβ-cat in well-differentiated colorectal cancer was significantly higher than that in poorly differentiated,54.2%（13/24） versus 23.8%（5/21） .The re-expression rate of β-cat in metastatic lymph nodes of tubular or papillary adenocarcinoma and mucinous adenocarcinoma was 35.7%（10/28） and 47.1%（8/17） ,respectively.The re-expression rate of β-cat in metastatic lymph nodes was independent with the tumor location,invasion depth,and the gender and age of patients.（2） RT-PCR results：There were different expression levels ofβ-cat mRNA in 45 cases of hunman advanced colorectal cancers and their metastatic lymph nodes.The relative expression value of β-cat mRNA in colorectal cancers was（0.724±0.006） ,which was significantly lower than that in the normal colorectal mucosa（0.785±0.017,t=21.066,P〈0.01） .The relative expression value of β-cat mRNA in metastatic lymph nodes was significantly higher than that in primarily focus,and significantly lower than that in normal colorectal mucosa.At the same time,the expressions ofβ-cat mRNA in metastatic lymph nodes were significantly correlated with the differentiating degree and histological type of tumor.（3） Western-blot results：There wereβ-cat protein expression in all the 25 cases of normal colorectal mucosa,while the different levels of β-cat protein expression were detected in 41 cases of primary tumors and the corresponding metastatic lymph nodes of total 45 cases.The β-cat protein expression was not detected in the primary tumors of 4 cases of colorectal cancer,but was detected in the metastatic lymph nodes of one of the four cases of colorectal cancer.The relative strength of β-cat protein in primary tumors was 6～108（54.3±38.1） in 41 cases of colorectal cancer,which was significantly lower than that in normal colorectal mucous membrane 15～172（95.4±49.8） .The β-cat protein expression in metastatic lymph nodes was significantly higher than that in primary focus,but was lower than in the normal colorectal mucosa.In metastatic lymph nodes from well-differentiated and moderately differentiated primary cancers,the relative intensity of β-cat protein expression were significantly higher than that from poorly differentiated cancers.Theβ-cat protein expression in tubular or papillary adenocarcinoma was significantly higher than that in mucinous adenocarcinoma.Conclusions In the development and progression of colorectal cancer,there is a certain changing characteristics of β-cat expression in the gene and protein levels.The characteristics make β-cat possible to become a new target for the diagnosis and treatment of colorectal cancer.
出处
《昆明医学院学报》
2010年第4期54-61,65,共9页
Journal of Kunming Medical College
基金
河北省自然科学基金资助项目(2005000762)
