细胞质内缝隙连接蛋白在肿瘤进展过程中的功能

Functions of intracytoplasmic connexin in tumor progression

缝隙连接细胞间通讯在维持组织稳态、调控细胞分化和肿瘤发生中发挥重要作用。研究证实缝隙连接介导的细胞间通讯抑制肿瘤的发生，在各种肿瘤组织中均发现有不同程度的细胞间缝隙连接通讯水平的下调，或由于缝隙连接蛋白表达减弱或缺失，或由于缝隙连接蛋白的细胞质内异位表达。长期以来普遍认为细胞质内缝隙连接蛋白表达只是引起细胞间缝隙连接通讯水平的下降，但是最近的一些研究陆续发现，细胞质内缝隙连接蛋白蓄积在肿瘤的进展过程中，发挥着不依赖于细胞间缝隙连接通讯的独特生物学功能。

A considerable amount of evidence established that gap junctional intercellular communication （GJIC） suppresses tumor development by halting the stage of tumor promotion. Consistently, GJIC is downregulated in tumors. The downregulation of GJIC is caused by not only the reduced expression level of connexin proteins but also their aberrant cytoplasmic localization. Although it has been thought long that cytoplasmic localization of connexin proteins is merely one of the mechanisms of the downregulation of GJIC, careful studies with human tumor samples indicated that the expression level of intracytoplasmic connexin proteins had different biological functions.