TUMOR PROMOTION IN LLC PK1 EPITHELIAL CELLS

描述：在上皮细胞中，从正常到异常的变化之一， 恶性状态包括获得几种不同的变化， 包括细胞-细胞粘附程度的降低。 肿瘤促进剂 TPA和细胞因子分散因子都破坏细胞-细胞连接。 是 TPA可能作用于至少部分信号转导， SF/HGF调节机制。 初步数据表明，PKC α和 δ同种型在该过程中是活性的。 此外， PKC介导的细胞连接破坏不涉及Map激酶 而是通过糖原直接调节细胞骨架成分 合成酶激酶（GSK 3）和腺瘤性结肠息肉病基因产物 （APC）。 该提案的具体假设是， 通过SF/HGF信号传导的细胞-细胞连接涉及PKC直接作用于 GSK/APC通路及其上游活化涉及PI 3 K和ras。 具体目的是：1）鉴定受PKC和SF/HGF影响的蛋白， 2)在LLC-PK 1细胞中表达显性阴性PKC δ，3）表达 GSK 3的野生型和显性阴性版本，并评估GSK 3作为PKC 细胞粘附破坏中的靶点，4）表征ras的相互作用 与PKC在细胞粘附破坏中的作用，以及5）表征 PI 3 K作为PKC的激活剂。

DESCRIPTION: In epithelial cells, one of the changes from a normal to a malignant state involves the acquisition of several distinct changes, including a lessening in degree of cell-cell adhesion. The tumor promoter TPA and the cytokine Scatter Factor both disrupt cell-cell junctions. It is possible that TPA is acting on at least part of the signal transduction mechanism regulated by SF/HGF. Preliminary data suggests that PKC alpha and delta isoforms are active in this process. In addition, the mechanism of PKC-mediated disruption of cell junctions does not involve the Map kinase pathway but rather direct modulation of cytoskeletal components via glycogen synthase kinase (GSK3) and the adenomatous polyposis coli gene product (APC). The specific hypothesis of this proposal is that the disruption of cell-cell junctions via the SF/HGF signaling involves PKC acting directly on the GSK/APC pathway and that its upstream activation involves PI3K and ras. The specific aims are 1) identify the proteins affected by PKC and SF/HGF, 2) express a dominant-negative PKCdelta in LLC-PK1 cells, 3) express wild-type and dominant-negative versions of GSK3 and assess GSK3 as a PKC target in cell adhesion disruption, 4) characterize the interaction of ras with PKC in the disruption of cell adhesion, and 5) characterize the role of PI3K as an activator of PKC.