Bladder cancer (BC) is one of the tumors which occur most frequently in urological system, but less is known about the expression of tight junction proteins and its clinical significance in BC. In this study, expression of claudin-4, zonula occludens-1 (ZO-1) and zonula occludens-1 nucleic acid-binding protein (ZONAB), in BC tissues, adjacent nontumor tissue (ANTT), and BC cell lines was examined by Western blotting, semiquantitative RT-PCR, and immunohistochemistry, and then, the clinical significance of these proteins was investigated. The mRNA and protein expression of ZONAB were significantly upregulated, while those of ZO-1 was significantly downregulated in some BC cell lines and tissues in comparison with nontumor urothelial cell lines and ANTT. High expression rate of ZO-1 and ZONAB had negative correlation in BC tissues and was also correlated with muscle-invasive lesions in BC tissues. In conclusion, the expression of tight junction proteins is significantly altered in BC and ZO-1, and ZONAB interaction might be involved in BC development.

中文翻译：

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紧密连接蛋白在膀胱癌中的表达发生改变

膀胱癌（BC）是泌尿系统最常见的肿瘤之一，但对紧密连接蛋白的表达及其在 BC 中的临床意义知之甚少。在本研究中，检测了 BC 组织、邻近非肿瘤组织 (ANTT) 和 BC 细胞系中 claudin-4、封闭带-1 (ZO-1) 和封闭带-1 核酸结合蛋白 (ZONAB) 的表达通过Western印迹、半定量RT-PCR和免疫组化，研究了这些蛋白质的临床意义。与非肿瘤尿路上皮细胞系和 ANTT 相比，ZONAB 的 mRNA 和蛋白质表达显着上调，而 ZO-1 的 mRNA 和蛋白表达在某些 BC 细胞系和组织中显着下调。ZO-1 和 ZONAB 的高表达在 BC 组织中呈负相关，也与 BC 组织中的肌肉浸润性病变相关。总之，紧密连接蛋白的表达在 BC 和 ZO-1 中显着改变，并且 ZONAB 相互作用可能参与了 BC 的发展。