PKC ISOZYMES AND INTESTINAL EPITHELIAL GROWTH CONTROL

理解协调这一过程的信号通路 肠上皮自我更新仍然不完全。基于 越来越多的证据表明蛋白激酶C成员的作用 (PKC)控制细胞生长的信号转导分子家族， 差异化，本研究提出的长期目标 应用是（a）定义单个PKC同工酶的功能 调节正常肠的更新过程，和（B）tp 确定PKC同工酶信号通路的改变如何促进 肠道疾病的发展。我们之前的研究支持 假设单个PKC同工酶是 调节肠上皮细胞信号通路 生长/细胞周期进程，以及这些途径中的畸变 有助于肿瘤疾病中观察到的细胞生长失调， 其他条件。为了验证这一假设，一个综合的体外和体内 体内方法将用于解决以下具体目标：（1） 研究单个PKC同工酶控制细胞凋亡的能力， IEC-18肠隐窝细胞系中的周期进展，使用 四环素调节的机制，参与PKC同工酶- 介导的IEC-18细胞周期阻滞，使用各种生化和 分子方法，（3）定义参与的信号事件， PKC介导的细胞周期蛋白依赖性激酶抑制剂的诱导 p21/waf/cip 1在IEC-18细胞中的表达，通过检测MAPK通路，p53 生长抑制蛋白和转录因子的Sp家族， (4)为了研究PKC α在肿瘤细胞中的生长调节功能， 体内肠上皮，使用嵌合转基因小鼠模型 地穴中过表达野生型或显性负性PKC α， 绒毛细胞，和（5）以确定改变的顺序， PKC同工酶表达和亚细胞分布 结肠癌的发生，使用Min小鼠和二甲基肼 小鼠（和大鼠）化学诱导结肠致癌作用模型。 这些研究预计将加强我们对作用的理解， PKC同工酶在肠上皮细胞生长控制和tof 它们对结肠肿瘤形成的贡献。

Understanding of the signaling pathways that orchestrate the process of intestinal epithelial self-renewal is still incomplete. Based on increasing evidence for the role(s) of members of the protein kinase C (PKC) family of signal transduction molecules in control cell growth and differentiation, the long-term goals of the research proposed in this application are (a) to define the function(s) of individual PKC isozymes in regulation of the renewal process in the normal intestine, and (b) tp determine how alterations in PKC isozyme signaling pathways contribute to the development of intestinal disease. Our previous studies support the hypothesis that individual PKC isozyme(s) are key components of signaling pathway(s) that regulate intestinal epithelial cell growth/cell cycle progression, and that aberrations in these pathways contribute to the dysregulate cell growth seen in neoplastic disease and other conditions. To test this hypothesis, an integrated in vitro and in vivo approach will be used to address the following Specific Aims: (1) to investigate the ability of individual PKC isozyme(s) to control cell cycle progression in the IEC-18 intestinal crypt cell lines, using tetracycline-regulated machinery that are involved in PKC isozyme- mediated IEC-18 cell cycle arrest, using a variety of biochemical and molecular approaches, (3) to define the signaling events involved in PKC-mediated induction of the cyclin dependent kinase inhibitor p21/waf/cip1 in IEC-18 cells, by examining the MAPK pathway, the p53 growth suppressor protein and the Sp family of transcription factors, (4) to investigate the growth-regulatory functions of PKC alpha in the intestinal epithelium in vivo, using chimeric-transgenic mouse models over-expressing wild-type or dominant-negative PKC alpha in crypt and villus cells, and (5) to define the sequence of alterations in individual PKC isozyme expression and subcellular distribution during colon carcinogenesis, using the Min mouse and the dimethylhydrazine model of chemically-induced colon carcinogenesis in mice (and rats). These studies are expected to enhance our understanding of the role(s) of PKC isozyme(s) in intestinal epithelial cell growth control and tof their contribution to the development of colonic neoplasia.