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Abnormalities of structure, function, expression, and signal transduction of ERK in relation to carcinogenesis

ERK结构、功能、表达和信号转导异常与癌变相关

基本信息

批准号：
16390520
负责人：
TSUCHIDA Nobuo
金额：
$ 9.02万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16390520/
关键词：
ERK mutation binding protein GST-fusion protein two hybrid oral cancer drosophila melanogaster SNT-2 Mutation binding protein リン酸化 CDドメイン口腔扁平上皮癌 Naf1 MKP-1 AKT

项目摘要

We found a point mutation at the codon 322 from glutamic acid (E) to lysine (K) within the CD domain of ERK2 of a cell line (HSC6) established from human oral squamous cell carcinoma. In this study we aimed to elucidate (1)biochemical, biophysical, and biological changes of ERK2 mutant by comparing with the normal couterpart and (2) incidence of such mutations in oral cancer. By these studies, we anticipated to get an answer how E322K mutation plays a role in the genesis of cancer. The results obtained are (1) E322K protein lost activity to bind MAPK phosphatase, resulting in constitutive activation of mutant protein, (2) cells exogenously expressing E322K gained growth advantage in soft agar, (3) E322K showed slightly less neurite-like forming activity in PC12 cells, (4) transgenic D, rosophila carrying E322K showed weak abnormality in development of compound eye and (5) no significant mutation was found except for 3 cases of polymorphic base changes in the CD domain out of 88 oral cancer samples. These results suggested that E322K mutant has weak activity toward cellular transformation and abnormal development but the incidence of mutation was low if there is.Besides, we obtained results suggesting (1) that SNT-2 binds to preferentially phosphorylated ERK and to EGF receptor, which results in down-regulation of EGF signaling by a feed back loop mechanism, (2) that aberrant expression of Naf1, another ERK2 binding protein, was observed in oral cancer cell lines and this protein may protect cells from apoptosis in G2/M-arrested cells

我们在人口腔鳞状细胞癌细胞系HSC 6中发现ERK 2 CD结构域322位密码子由谷氨酸（E）突变为赖氨酸（K）。本研究的目的是通过与正常对照的比较，阐明（1）ERK 2突变的生化、生物物理和生物学变化;（2）此类突变在口腔癌中的发生率。通过这些研究，我们期望能够得到E322 K突变在肿瘤发生中的作用的答案。结果表明：（1）E322 K蛋白失去了与MAPK磷酸酶结合的活性，导致突变蛋白的组成性激活;（2）外源表达E322 K的细胞在软琼脂中生长优势明显;（3）E322 K在PC 12细胞中的神经突样形成活性略低;（4）转基因D，携带E322 K基因的果蝇复眼发育出现弱异常;（5）在88例口腔癌标本中，除3例CD结构域发生多态性碱基改变外，未发现明显突变。这些结果表明，E322 K突变体对细胞转化和异常发育的活性较弱，但如果存在，突变的发生率较低。此外，我们获得的结果表明：（1）SNT-2优先与磷酸化ERK和EGF受体结合，这通过反馈环机制导致EGF信号转导的下调;（2）Naf 1的异常表达，在口腔癌细胞系中观察到另一种ERK 2结合蛋白，该蛋白可以保护G2/M停滞细胞免受细胞凋亡