PKC ISOZYMES AND INTESTINAL EPITHELIAL GROWTH CONTROL

对协调这一过程的信号通路的理解 肠上皮细胞的自我更新仍不完全。基于 越来越多的证据表明蛋白激酶C成员的作用(S) (PKC)家族信号转导分子在控制细胞生长和 差异化，这项研究的长期目标是 应用是：(A)定义单个蛋白激酶C同工酶的功能(S) 在调节正常肠道的更新过程中，和(B)tp 确定PKC同工酶信号通路的改变如何起作用 与肠道疾病的发展有关。我们之前的研究支持 个体蛋白激酶C同工酶(S)是关键成分的假说 调控肠上皮细胞的信号通路(S) 生长/细胞周期进程，以及这些途径中的异常 导致肿瘤疾病中出现的细胞生长失调 其他条件。为了验证这一假设，一种集成的体外和体内 将使用VIVO方法来解决以下具体目标：(1) 个体蛋白激酶C同工酶(S)控制细胞能力的研究 IEC-18肠隐窝细胞系的周期进展 参与PKC同工酶的四环素调节机制- 介导的IEC-18细胞周期停滞，使用多种生化和 分子方法，(3)定义所涉及的信号事件 蛋白激酶C介导的细胞周期蛋白依赖性激酶抑制物的诱导 P21/WAF/cip1在IEC-18细胞中的表达 生长抑制蛋白和转录因子Sp家族， (4)探讨PKCα在大鼠脑内的生长调节作用。 利用嵌合转基因小鼠模型体内的肠道上皮细胞 在隐窝和隐窝中过表达野生型或显性阴性的PKCα 绒毛细胞，和(5)确定改变的顺序 个体PKC同工酶的表达及亚细胞分布 用小白鼠和二甲基肼诱发结肠癌 化学诱导小鼠(和大鼠)结肠癌模型的建立。 这些研究有望增进我们对这一角色的理解(S) 蛋白激酶C同工酶(S)在肠上皮细胞生长调控和TOF中的作用 它们在结肠肿瘤发生发展中的作用。

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.