AKT2 FUNCTION AND ONCOGENIC ACTIVITY

描述：(改编自调查人员摘要)申请者 先前报道的AKT2癌基因扩增/过表达 10%-20%的人胰腺癌和卵巢癌，而 相关基因AKT1在人类癌症中很少观察到。他们有 证明过表达AKT2可以转化NIH3T3细胞，并且 Akt2反义RNA抑制人胰腺癌细胞的致瘤表型 显示AKT2扩增/过表达的癌细胞。Akt2编码 一种氨基末端含有Pleckstrin的丝氨酸-苏氨酸激酶 许多信号分子的同源(PH)结构域特征。角色 到目前为止，AKT2在信号转导中的作用还没有得到详细的研究。 最近，申请人观察到AKT2是由表皮激活的 生长因子(EGF)通过与AKT1不同的途径发挥作用。此外， 他们已经证明AKT2在靶向的组织中大量表达 胰岛素，例如棕色脂肪和肌肉，这表明AKT2激酶可以 参与葡萄糖的运输。这样做的广泛、长期目标是 该项目旨在阐明AKT2蛋白的正常细胞功能和 确定AKT2基因扰动在人类癌症中的重要性。 拟议的实验旨在检验AKT2是一种 参与细胞调控的重要信号调节因子 增殖，AKT2基因异常表达导致 某些人类上皮性肿瘤的发展或进展。这个 具体目标有三个：1)直接测试是否过度表达 Akt2在转基因小鼠中是致癌的。Akt2转基因小鼠将用于 确定Akt2单独过表达是否在体内具有致瘤作用 模特。为了确定Akt2的异常表达是否可能在 多步致癌，致瘤性也将在子代中进行检测 Akt2转基因小鼠与携带其他致癌基因转基因的小鼠杂交。 2)阐明AKT2在EGF-1和EGF-2信号转导中的作用 胰岛素介导的信号。为了阐明正常的细胞功能 Akt2，他们将描绘特定的EGFR信号转导途径 有助于AKT2的激活，并确定AKT2在 葡萄糖的运输。3)定义AKT2和两个 酵母相互作用确定的潜在重要信号伙伴 诱捕。以确定这些物质的生理意义 交互，我们将测试这两个候选AKT2交互组件是否可以 调节AKT2的激酶和转化活性。总体而言， 拟议的研究将通过以下方式产生关于机制的重要信息 哪些AKT2介导细胞信号并阐明AKT2通过哪些机制 变化会导致肿瘤的形成。

DESCRIPTION: (adapted from the investigator's abstract) The applicants previously reported amplification/overexpression of the AKT2 oncogene in 10%-20% of human pancreatic and ovarian carcinomas, whereas alterations of the related gene, AKT1, are rarely observed in human cancer. They have demonstrated that overexpression of AKT2 transforms NIH 3T3 cells, and that AKT2 antisense RNA inhibits the tumorigenic phenotype of human pancreatic cancer cells exhibiting amplification/overexpression of AKT2. AKT2 encodes a serine-threonine kinase whose amino-terminus contains a pleckstrin homology (PH) domain characteristic of many signaling molecules. The role of AKT2 in signal transduction has not been explored in detail to date. Recently, the applicants have observed that AKT2 is activated by epidermal growth factor (EGF) through a pathway distinct from that of AKT1. Moreover, they have shown that AKT2 is abundantly expressed in tissues targeted by insulin, e.g., brown fat and muscle, suggesting that the AKT2 kinase could be involved in glucose transport. The broad, long-term objective of this project is to elucidate the normal cellular function of the AKT2 protein and determine the importance of perturbations of the AKT2 gene in human cancers. The proposed experiments are designed to test the hypothesis that AKT2 is an important signal mediator that contributes to the control of cell proliferation, and that aberrant expression of the AKT2 gene contributes to the development or progression of certain human epithelial tumors. The specific aims are threefold: 1) Directly test whether overexpression of Akt2 is oncogenic in transgenic mice. Akt2 transgenic mice will be used to ascertain if overexpression of Akt2 alone is tumorigenic in an in vivo model. To determine if aberrant expression of Akt2 could be important in multistep oncogenesis, tumorigenicity will also be examined in progeny of Akt2 transgenic mice crossed with mice harboring other oncogenic transgenes. 2) Delineate the role of AKT2 in the transduction of EGF- and insulin-mediated signals. To elucidate the normal cellular function of AKT2, they will delineate the specific EGFR signal transduction pathway contributing to the activation of AKT2 and determine the role of AKT2 in glucose transport. 3) Define the interaction between AKT2 and two potentially important signaling partners identified by yeast interaction trapping. To determine the physiological significance of these interactions, we will test whether these two candidate AKT2 interactors can regulate the kinase and transforming activities of AKT2. Overall, the proposed studies will yield important information concerning mechanisms by which AKT2 mediates cellular signals and elucidate mechanisms by which AKT2 alterations contribute to neoplasia.