Elucidating a Novel Akt Activation Mechanism for Targeted Prostate Cancer Therapy

描述（由申请人提供）：本提案的目标是揭示新发现的Akt1 S477/T479磷酸化促进Akt活化和肿瘤发生的分子机制，以及检查特异性抑制该磷酸化事件的上游激酶（如Cdk2/Cyclin A）是否可以阻断前列腺肿瘤的生长。我的长期职业目标是应用分子和细胞生物学的见解来理解在人类恶性肿瘤发展中重要的解除调控的蛋白激酶激活的生理意义，并寻找合适的可药物激酶靶点。Akt在人类癌症中被观察到过度激活，这与激素抗性表型和不良预后有关。PI3K/Akt通路在前列腺癌中的重要意义使其成为开发小分子抑制剂的一个有吸引力的靶点。然而，Akt抑制剂的应用在临床试验中遇到了困难，因为它会诱导癌细胞和正常体细胞的凋亡。因此，为了实现对癌细胞的特异性根除，确定区分癌细胞和正常细胞的信号通路至关重要。我们的初步数据显示，另一个癌症标志Cdk2/Cyclin A可以以细胞周期依赖的方式直接磷酸化Akt1的S477/T479位点，从而控制Akt的激活，为癌细胞提供特定的生长优势。因此，我们的目的是研究Akt1-pS477/pT479磷酸化促进Akt活化的分子机制，以及抑制其上游活化激酶Cdk2/Cyclin A是否能特异性杀死癌细胞。在本提案中，我计划：1)阐明细胞周期依赖性Akt激活的分子机制；2)研究Akt1 S477/T479磷酸化在前列腺肿瘤发生中的作用；3)确定靶向抑制Akt尾部磷酸化是否通过抑制Akt激活来抑制前列腺癌的发展。这个K99/R00奖励将为我提供保护的时间来追求这个提案的假设，获得新的技能来执行实验和解决问题。此外，该奖项还将使我能够专注于独立进行基础和转化研究，并培养未来的青年科学家。如果我获得这个奖项，我将在贝斯以色列女执事医疗中心（BIDMC）和哈佛医学院进行这项研究，那里是PI3激酶信号传导和前列腺癌研究领域的权威所在。这些研究的结果将有助于阐明Akt1-pS477/pT479介导的Akt活化的详细分子机制，为使用特异性Cdk2/Cyclin A药物干预人类癌症个体化治疗的基本原理提供证据，并提供初步的动物实验结果，以测试特异性靶向Cdk2/Cyclin A是否可以在体内延缓前列腺癌的进展。

DESCRIPTION (provided by applicant): The goal of this proposal is to uncover the molecular mechanisms by which the newly identified Akt1 S477/T479 phosphorylation contributes to Akt activation and tumorigenesis, as well as to examine whether specifically inhibiting the upstream kinases for this phosphorylation event such as Cdk2/Cyclin A could block prostate tumor growth. My long-term career goals are to apply the insights of molecular and cellular biology to understand the physiological significance of deregulated protein kinase activation that is important in the development of human malignancies, and to search for proper drugable kinase targets. Akt is observed to be hyperactivated in human cancers, which is associated with the hormone-resistant phenotype and a poor prognosis. The significance of the PI3K/Akt pathway in prostate cancer has made it an attractive target for the development of small molecular inhibitors. However, the application of Akt inhibitors met difficulties in clinical trials due to induction of apoptosis in both cancer cells and normal somatic cells. Thus, to achieve specific eradication of cancer cells, it is critical to pinpoint the signaling pathways that distinguish caner cells from normal cells. Our preliminary data showed that another cancer hallmark, Cdk2/Cyclin A, could directly phosphorylate Akt1 at S477/T479 in a cell cycle dependent manner to govern Akt activation, providing specific growth advantages for cancer cells. Thus we are aiming to examine the molecular mechanisms through which Akt1-pS477/pT479 phosphorylation facilitates Akt activation and whether inhibiting its upstream activation kinase, Cdk2/Cyclin A could specifically kill cancer cells. In this proposal, I plan to: 1) Elucidate the molecular mechanisms underlying cell cycle-dependent Akt activation; 2) Examine the role of of Akt1 S477/T479 phosphorylation in prostate tumorigenesis; 3) Determine whether targeted inhibition of Akt tail phosphorylation suppresses prostate cancer development through suppressing Akt activation. This K99/R00 award will provide protected time for me to pursue the hypotheses of this proposal, obtain new skill sets to execute experiments and solve problems. In addition, the award will also allow me to focus my efforts on independently conducting basic and translational research, and to train future young scientists. Should I receive this award, I will pursue this research in Beth Israel Deaconess Medical Center (BIDMC) and Harvard Medical School, where authorities in the fields of PI3 kinase signaling and prostate cancer research locate. The outcome of the proposed studies will help elucidate the detailed molecular mechanisms for Akt1-pS477/pT479 mediated Akt activation, provide evidence toward the rationale for using specific Cdk2/Cyclin A pharmacological intervention in personalized medicine for human cancers and deliver initial animal experimental results to test whether specifically targeting Cdk2/Cyclin A could retard prostate cancer progression in vivo.