血管内皮钙黏蛋白在非小细胞肺癌中的表达及其意义

Expression and significance of vascular endothelial cadherin in non-small cell lung cancer

摘要:

目的：探讨血管内皮钙黏蛋白（vascular endothelial cadherin，VE-cadherin）在非小细胞肺癌（non-small cell lung cancer，NSCLC）中的表达及其与临床病理特征之间的关系，并分析其与血管内皮生长因子（vascular endothelial grow factor，VEGF）之间的相关性。方法：应用免疫组化SP法检测72例NSCLC组织及相应癌旁正常组织VE-cadherin的表达情况；其中34例用qRT-PCR法检测mRNA的表达情况，并以 VEGF为阳性参照。Western blot检测肺癌细胞株A549和人正常支气管上皮细胞（nor－mal human bronchial epithelial cells，NHBEC）中VE-cadherin的表达，以及干扰后各细胞株的表达情况。结果：72例NSCLC组织癌细胞和VE-cadherin的阳性表达率分别为69.4%、52.8%，均明显高于对应癌旁正常组织肺泡上皮细胞0%和血管内皮细胞20.8%（P<0.05）；有淋巴结转移组中的表达量均明显高于无淋巴结转移组（P<0.05）；Ⅲ、Ⅳ期的阳性表达率均明显高于Ⅰ、Ⅱ期（P<0.05）。VEGF在NSCLC组织癌细胞和血管内皮细胞中的阳性表达率分别为84.7%、62.5%，均显著高于对应的癌旁正常组织肺泡上皮细胞16.7%和血管内皮细胞29.2%（P<0.05）。经qRT-PCR分析，VE-cadherin mRNA在癌组织和癌旁正常组织中的相对表达量分别为1.15±0.87、0.70±0.57；VEGF mRNA的相对表达量分别为1.39±1.17、0.79±0.65（P<0.05）。两者在蛋白水平和mRNA水平均呈正相关（P=0.001，P=0.008）。Western blot结果示在A549细胞株中可检测到VE-cadherin表达，但在NHBEC中不表达。siRNA可降低VE-cadherin在A549细胞株中的表达。结论：VE-cadherin可能在NSCLC血管生成中起重要作用，且可能与VEGF具有协同作用，siRNA可有效抑制VE-cadherin在肺癌细胞株A549中的表达。

Abstract:

Objective：To investigate the expression of vascular endothelial cadherin（VE-cadherin） in non-small cell lung cancer（NSCLC） and its association with the clinicopathological characteristics and vascular endothelial grow factor（VEGF）. Methods：Expression of VE-cadherin was examined at protein level by immunohistochemical staining in 72 cases of NSCLC tissues and their adjacent non-neoplastic tissues；34 of which were measured at mRNA level by qRT-PCR and VEGF was taken as positive reference. Expression of VE-cadherin in lung cancer cell line A549 and normal human bronchial epithelial cells（NHBEC） was detected by Western blot and VE-cadherin gene expression was inhibited with siRNA in A549 cells. Results：Positive rates of VE-cadherin in cancer cells and vascular endothelial cells were 69.4% and 52.8%，which were higher than those in alveolar epithelial cells（0%） and vascular endothelial cells（20.8%） in adjacent non-neoplastic tissues（P<0.05）. Positive rates of VE-cadherin were higher in cases with lymph node metastasis than in cases without lymph node metastasis（P<0.05）. Positive rates of VE-cadherin were higher at Ⅲ and Ⅳ stage than atⅠand Ⅱstage（P<0.05）. Positive rates of VEGF in cancer cells and vascular endothelial cells were 84.7% and 62.5%，which were higher than those in alveolar epithelial cells（16.7%） and vascular endothelial cells（29.2%） in adjacent non-neo－plastic tissues（P<0.05）. qRT-PCR results demonstrated that relative expression of VE-cadherin mRNA in NSCLC tissues and adjacent non-neoplastic tissues were 1.15±0.87 and 0.70±0.57；relative expression of VEGF mRNA were 1.39±1.17 and 0.79±0.65（P<0.05）. VEGF and VE-cadherin were positive correlated at both protein and mRNA levels（P=0.001，P=0.008）. Western blot demon－strated that VE-cadherin expression could be detected in the A549 cells，but not in NHBEC and sequence-specific siRNA can significantly decreased expression of VE-cadherin in A549 cells. Conclusions：VE-cadherin may play an important role in angiogene－sis and act in a synergistic manner with VEGF in NSCLC. siRNA can effectively inhibit the expression of VE-cadherin in A549 cells.