胆管癌组织及其胆汁糖蛋白末端唾液酸结构的改变及其意义

Changes in terminal sialyl residues linked to N-glycans in the tissue of bile duct carcinoma and bile glycoproteins

目的探讨胆管癌组织及其胆汁糖蛋白N 型糖链末端唾液酸的结构特点及意义。方法采用半定量RT PCR法 ,分析 35例胆管癌和 35例良性胆管组织唾液酸转移酶ST6Gal Ⅰ和ST3Gal ⅢmRNA的表达 ;采用能识别末端唾液酸结构的麦胚凝集素 (WGA) ,对良恶性标本进行WGA组织化学染色 ,并进行图像分析 ;对各良恶性胆汁进行WGA点印迹分析。结果胆管癌组织中ST3Gal Ⅲ和ST6Gal ⅠmRNA表达均增强 (P <0 0 1) ,以ST3Gal Ⅲ明显 ;胆管癌组织WGA阳性率为 10 0 % (35 / 35 ) ,良性组织为 4 3% (15 / 35 ) ,胆管癌WGA强度指数高于良性对照组 (P <0 0 1) ;胆管癌组织WGA指数与ST3Gal ⅢmRNA表达正相关 ,二者均与TNM分期、肿瘤分化、转移等有关 ;恶性病变胆汁WGA点印迹阳性率 (83% )高于良性病变胆汁 (17% ) ,且与胆管癌组织WGA指数有关。结论胆管癌细胞糖蛋白末端唾液酸含量增加 ,并发生连接键型的变化 ,具有特征性 ,与胆管癌生物学特性有关 ;在分泌的胆汁中也可检测到糖蛋白末端唾液酸含量增加。

ObjectiveTo explore the clinical significance and characteristics about terminal sialyl residues linked to N-glycans in the tissue and bile glycoproteins from bile duct carcinoma. MethodsThe mRNA expression of sialyltransferases, including ST3Gal-Ⅲ and ST6Gal-Ⅰ, was detected in the tissue extracts of 35 cases with bile duct carcinoma(BDC) and 35 cases of benign biliary disease (BBD) by semiquantitative reverse transcription-polymerase chain reaction(RT-PCR). With the lectin of WGA(Triticum valgaris agglutinin), which can recognise the terminal sialyl residues in N-glycans, all the specimens of BDC and BBD were subject to lectin histochemical staining, followed by computer-aided digital analysis. Lectin dot-blotting with horseradish peroxidase-labeled WGA was performed for the bile samples from each of the 35 cases of BDC and BBD. ResultsThe mRNA levels of ST3Gal-Ⅲ and ST6Gal-Ⅰ elevated in BDC(P<0.01). The WGA positive rates in BDC and BBD tissue were 100% and 43% respectively, and the WGA staining indices (WSIs) were also higher in BDC than in BBD (P<0.01). WSIs were positively correlated with ST3Gal-Ⅲ mRNA levels in BDC tissue, and both of them were related to TNM stage, differentiation and metastasis of BDC. The positive rates of bile WGA dot-blotting in malignant group (83%) were higher than in benign group(17%)(P<0.01) , and related to the WSIs of BDC tissue. ConclusionsThe terminal sialyl residues linked to N-glycans in glycoproteins from the BDC cells alter characteristically, with the increase of sialic acid and the change of its linked type, both of which are related to the biologic features of BDC.