AKT2 Function and Oncogenic Activity

描述：(申请人提供)与其他AKT/蛋白激酶B家族一样 成员中，AKT2被生长因子通过磷脂酰肌醇激活 3-激酶(PI3K)，从而介导不同细胞内的信号 细胞凋亡抑制、细胞增殖和胰岛素等过程 发信号。AKT2基因在AKT家族成员中是独一无二的，因为它 在胰岛素靶向的组织中优先表达，并且是 在某些人胰腺癌和卵巢癌中扩增/过表达。在……里面 此外，AKT2激酶的激活似乎在 这些肿瘤类型。此外，AKT2激活上调IGF-I受体 表达并促进胰腺癌细胞的侵袭性 外源性IGF-I这个项目广泛的、长期的目标是阐明 AKT2的正常细胞功能及其意义的确定 胰腺癌的微扰。拟议的实验测试了 假设AKT2在正常发育中发挥重要作用，并且 AKT2的异常表达/激活参与了AKT2的发生发展 一些胰腺癌的进展。具体目标有四个方面：1) 确定Akt2基因敲除小鼠的表型以阐明Akt2的功能 在正常胚胎发育和成人组织中。除 Akt2(-/-)小鼠的表型/组织学特征和代谢研究 并将进行衍生细胞以确定Akt2在胰岛素中的作用 新陈代谢。将检查促凋亡刺激的效果以确定 如果Akt2的缺失降低了对程序性细胞死亡的抵抗力。2)确定 AKT2表达/活性在人胰腺癌和胰腺癌中的作用机制 一种小鼠癌症模型。Akt2的表达和活性将在人体内进行评估 胰腺肿瘤和早期病变。确定AKT2的发病机制(S) 胰腺癌组织中PTEN蛋白表达与P13K活性的关系 将会被调查。为了阐明Akt2在肿瘤发生中的作用机制， Akt2(-/-)小鼠将与PTEN(+/-)小鼠杂交，以确定是否丢失 Akt2亚型本身能够减少与以下因素相关的肿瘤发生 PTEN缺失。3)确定IGF-1在胰腺癌中是否起重要作用 AKT2激活及AKT2介导的细胞侵袭性 IGF-IR过表达。此外，将使用胶原酶分解试验来 定义这一过程中涉及的机制。4)描述交互作用 在AKT2和本实验室克隆的一个新的接头APPL之间。的作用 APPL在细胞凋亡抑制和肿瘤发生中的作用将被描述。总体而言， 拟议的调查将产生关于AKT2功能的重要见解 和致癌机制。

DESCRIPTION: (provided by applicant) Like other AKT/protein kinase B family members, AKT2 is activated by growth factors through phosphatidylinositol 3-kinase (PI3K) and thereby mediates signals involved in diverse cellular processes such as apoptosis inhibition, cell proliferation, and insulin signaling. The AKT2 gene is unique among members of the AKT family, in that it is preferentially expressed in tissues targeted by insulin and is amplified/overexpressed in some human pancreatic and ovarian carcinomas. In addition, activation of the AKT2 kinase appears to be common occurrence in these tumor types. Moreover, AKT2 activation up-regulates IGF-I receptor expression and promotes invasiveness of pancreatic cancer cells in response to exogenous IGF-I. The broad, long-term objective of this project is to elucidate the normal cellular function of AKT2 and determine the significance of AKT2 perturbations in pancreatic cancer. The proposed experiments test the hypothesis that AKT2 plays an important role in normal development, and that aberrant expression/activation of AKT2 contributes to the development of progression of some pancreatic carcinomas. The specific aims are fourfold: 1) Delineate the phenotype of Akt2 knockout mice to elucidate the function of Akt2 in normal embryonic development and in adult tissues. In addition to the phenotypic/histologic characterization, metabolic studies of Akt2 (-/-) mice and derived cells will be carried out to determine the role of Akt2 in insulin metabolism. The effect of pro-apoptotic stimuli will be examined to determine if loss of Akt2 decreases resistance to programmed cell death. 2) Determine the mechanistic role of AKT2 expression/activity in human pancreatic cancer and in a mouse cancer model. AKT2 expression and activity will be evaluated in human pancreatic tumors and early lesions. To determine the mechanism(s) of AKT2 activation in pancreatic cancers, PTEN protein expression and P13K activity will be investigated. To elucidate the mechanistic role of Akt2 in oncogenesis, Akt2 (-/-) mice will be crossed with PTEN (+/-) mice to determine if loss of the Akt2 isoform alone is capable of diminishing oncogenesis associated with PTEN loss. 3) Determine if IGF-1 plays a significant role in pancreatic cancer cell invasiveness in connection with AKT2 activation and with AKT2-mediated IGF-IR overexpression. Furthermore, collagenolytic assays will be employed to define the mechanisms involved in this process. 4) Characterize the interaction between AKT2 and a novel adaptor APPL, cloned in this laboratory. The role of APPL in apoptosis inhibition and oncogenesis will be delineated. Overall, the proposed investigations will yield important insights regarding AKT2 function and oncogenic mechanisms.