Molecular mechanism for cell-cell adhesion in canceration and metastasis

90%以上的恶性肿瘤来源于上皮。因此，在本项目中，我们重点分析了紧密连接和ERM蛋白，以阐明其性质。上皮细胞。主要研究结果如下：产生claudin -1缺陷小鼠。它们的表皮屏障受到影响，表皮细胞增殖出现异常。产生了claudin -5缺陷小鼠。它们的血脑屏障以一种大小依赖的方式受到影响。从药物给药到脑肿瘤的角度来看，这一发现是有趣的。在活细胞中成功地观察到基于claudin的紧密连接链的动态行为。他们的行为比预期的更有活力。Snail是一种转录因子，在癌细胞的上皮-间质转化过程中起关键作用，在癌细胞转移过程中起重要作用。我们发现Snail通过直接结合这些基因的启动子区域的e -box，完全抑制了occludin和claudin的转录。Claudin-1被证明在人类结肠癌中过度表达（与Nakamura教授小组合作）。我们建立了一个系统，在这个系统中，某个基因可以在培养的上皮细胞中被双重敲除。利用该系统，建立了缺乏ZO-1和ZO-2表达的上皮细胞系。通过x射线衍射分析（与hakozaki教授小组合作）阐明了NF2基因产物的结构，NF2是一种类似erm的肿瘤抑制基因。

More than 90% of malignant tumors are derived from the epithelium. Thus, in this project, we focused on the analyses of tight junctions and ERM proteins to clarify the nature of the. epithelium. Major results are as follows:1. Claudin-1-deficient mice were generated. Their epidermal barrier was affected, and the proliferation of epidermal cells appeared to be abnormal.2. Claudin-5-deficient mice were generated. Their blood-brain barrier was affected in a size-dependent manner. This finding was intriguing from the viewpoint of drug deliver to the brain tumors.3. The dynamic behavior of claudin-based tight junction strands was successfully observed in live cells. Their behavior was more dynamic than ever expected.4. Snail, a transcription factor, plays a key role in the epithelial-mesenchymal transition, which is important in the metastasis of cancer cells. We found that Snail completely repressed the transcription of occludin and claudins through its direct binding to the E-boxes of the promoter regions of these genes.5. Claudin-1 was shown to be overexpressed in human colon cancer (in collaboration with Prof. Nakamura's group).6. We established the system, in which a certain gene can be double-knocked out in cultured epithelial cells. With this system, an epithelial cell line lacking the expression of ZO-1 and ZO-2 was established.7. The structure of the gene product of NF2, an ERM-like tumor suppressor gene, was clarified by X-ray diffraction analyses (in collaboration with Prof.Hakozaki's group).