AKT1 Oncogene in Carcinogenesis

描述：(改编自调查人员的摘要)我们之前 证明了AKT1是v-AKT的真正人类对应物，最近 在前列腺原发肿瘤中检测到AKT1激酶活性频繁升高， 乳房和卵巢。我们还观察到，激活的AKT1将NIH313 DN-AKT1抑制RAS的作用 转型。此外，两个AKI 1-相互作用蛋白已经被 鉴定，其中一个是APciB，含有4个AKT 1磷酸化位点 和3个SH3结构域，另一个是蛋白酶体b亚单位(PMSB4)，具有 AKT1磷酸化位点。AKT1在体外和体内磷酸化APaB和PSMB4 活着。此外，APaB与PAK 1激酶结合并增强AKT1诱导的细胞 生存和细胞生长。我们还展示了Aki I使p21Wafi磷酸化 并阻断p21对CDK4/6和CDC2激酶的抑制作用。激活的AKT1 覆盖P5 3诱导的GI停止。根据这些数据，我们假设 激活的AKT1及其相关蛋白与PAK1和p21串扰 WAFI通路有助于控制细胞恶性转化 细胞周期进程和细胞骨架重组。因此，AKT1可能是一个 有价值的肿瘤标志物和治疗干预的关键靶点 人类癌症。这个项目广泛的、长期的目标是阐明 AKT1蛋白的正常细胞功能及其重要性 AKT1通路在人类癌症中的扰动。具体目标是：1. 确定AKT1激活的临床病理意义及作用 前列腺癌和乳腺癌。这将通过(A)检查AKT1来实现 一系列原发性前列腺癌和乳腺癌中的激活和 AKT1激活与临床病理特征的相关性，以及(B)创建 前列腺特异性前盆启动子驱动的AKTJ转基因小鼠确定 激活的AKT1的过度表达是否具有致瘤性。2.定义交互 AKT1和由确定的两个潜在重要信令合作伙伴之间 酵母双杂交系统。我们将研究(A)AKT的影响 AKT1细胞生存通路上的1-相互作用蛋白，包括PAK1 激活，错误的磷酸化，NFIB激活，细胞色素c释放， 细胞骨架重组和p27降解，(B)AKT的影响 1-相互作用蛋白对AKT1致癌活性的影响，以及(C)相互作用蛋白对AKT1致癌活性的重要性 AKT1与其相关蛋白的结合域 发信号。3.检测p21蛋白AKT1磷酸化对细胞周期的影响 控制力。这将通过检查AKT1诱导的影响来实现 P21磷酸化对(A)p21和p21结合的亚细胞定位 细胞周期蛋白-CDK复合体的能力，(B)细胞周期蛋白-CDK活性，(C)Gi的组装 细胞周期蛋白CDK复合体和增殖细胞核抗原结合活性，以及(D)p21诱导的细胞周期 逮捕。4.将AKT1确定为癌症干预的关键靶点。这 将通过检查(A)直接抑制AKT1的效果来实现 对癌细胞生长的影响，(B)dN-AKT1和激活的AKT1对癌细胞生长的影响 化疗药物的敏感性，以及(C)潜在的AKT1抑制剂 体外和体内抑制肿瘤细胞生长的特异性和能力。

DESCRIPTION: (Adapted from the investigator's abstract) We previously demonstrated that AKT1 is the true human counterpart of v-akt and recently detected frequent elevated AKT1 kinase activity in primary tumors of prostate, breast and ovary. We have also observed that activated AKT1 transforms NIH 313 cells and induces membrane ruffling and that DN-AKT1 inhibits ras transformation. In addition, two AKI 1 -interation proteins have been identified, one of which is APciB that contains 4 AKT 1 phosphorylation sites and 3 SH3 domains, and the other is a proteasome b-subunit (PMSB4) that has an AKT1 phosphotylation site. AKT1 phosphorylates APaB and PSMB4 in vitro and in vivo. Moreover, APaB binds to PAK 1 kinase and enhances AKT1-induced cell survival and cell growth. We have also shown that AKI I phosphorylates p21 WAFI and abrogates p21 inhibitory effect on CDK4/6 and cdc2 kinases. Activated AKT1 overrides p5 3-induced Gi arrest. Based on these data, we hypothesize that that activated AKT1 and its associated proteins are cross-talk with PAK1 and p21 WAFi pathways to contribute to the control of malignant transformation, cell cycle progression and cytoskeleton reorganization. Thus, AKT1 could be a valuable tumor marker and a critical target for therapeutic intervention in human cancer. The broad, long-term objective of this project is to elucidate the normal cellular function of the AKT1 protein and determine the importance of perturbations of AKT1 pathway in human cancers. The specific aims are: 1. Determine the clinicopathologic significance and the role of AKT1 activation in prostate and breast cancer. This will be accomplished by (a) examining AKT1 activation in a large series of primary prostate and breast carcinomas and correlating AKT1 activation with clinicopathologic features, and (b) creating prostate-specific, probasin promoter-driven AKTJ transgenic mice to ascertain if overexpression of activated AKT1 is tumorigenic. 2. Define the interaction between AKT1 and two potentially important signaling partners identified by the yeast two-hybrid system. We will examine (a) the effects of AKT 1-interaction proteins on AKT1 cell survival pathway, including PAK1 activation, Bad phosphorylation, NFiB activation, cytochrome c release, cytoskeleton reorganization, and p27 degradation, (b) the effects of AKT 1-interaction proteins on AKT1 oncogenic activity, and (c) the importance of the binding domains between AKT1 and its associated proteins in AKT1 signaling. 3. Examine the effects of AKT1 phosphorylation of p21 on cell cycle control. This will be accomplished by examining the effects of AKT1-induced p21 phosphorylation on (a) subcellular localization of p21 and p21 binding ability to cyclinlCDK complexes, (b) cyclinlCDK activity, (c) assembly of Gi cyclinlCDK complexes and PCNA binding activity, and (d) p21-induced cell cycle arrest. 4. Determine AKT1 as a critical target for cancer intervention. This will be accomplished by examining (a) the effects of direct inhibition of AKT1 on cancer cell growth, (b) the effects of DN-AKT1 and activated AKT1 on sensitivity of chemotherapeutic drugs, and (c) potential AKT1 inhibitors' specificity and ability to inhibit tumor cell growth in vitro and in vivo.