Targeting the PI3K/AKT pathway in cancer using a pan-AKT degrader

摘要 丝氨酸/苏氨酸激酶AKT是磷脂酰肌醇3-激酶（PI 3 K）信号传导的中心组分 它是细胞生长、增殖和代谢等许多细胞过程的关键调节因子。 PI 3 K/AKT通路的异常激活破坏了增殖和存活的正常调节，导致 肿瘤发生AKT在超过50%的人类肿瘤中过度活化，使其成为最常见的分子生物学标记之一。 癌症的干扰。已经研究了几种ATP竞争性、变构性和共价泛AKT抑制剂。 目前正在开发并进行临床研究。然而，对AKT抑制的稳健的治疗应答 没有被观察到。我们假设，通过靶向蛋白降低细胞AKT蛋白水平， 降解可以增强依赖于AKT信号传导的杀死细胞的能力。异双功能降解剂 分子，也被称为PROTAC（蛋白水解靶向嵌合体），招募E3泛素连接酶进入紧密的 与靶蛋白接近以诱导其泛素化和随后的蛋白酶体降解。我们 开发了INY-03-041，一种泛AKT降解剂，由AKT抑制剂GDC-0068组成， 来那度胺，一种E3泛素连接酶Cereblon的招募者。蛋白质降解剂显示出几个优点 过度抑制剂，包括增强多靶点抑制剂的选择性、废除激酶非依赖性 功能和克服抗性突变。INY-03-041诱导所有的有效和选择性降解， 三种AKT同种型，并且在乳腺癌中与GDC-0068相比表现出增强的抗增殖作用 细胞推动这一应用的假设是，靶向AKT降解将更多地抑制癌细胞生长。 比AKT抑制更强，导致体内持久的反应，并且将是鉴定新的 AKT的生物学功能在目标1中，我将评价INY-03-041介导的AKT降解的后果 对细胞信号、增殖和存活的影响。本研究的目的是揭示急性心肌梗死后AKT的新功能。 蛋白质消耗，并鉴定对AKT降解敏感性的遗传或表观遗传生物标志物，其可 告知AKT降解的治疗适应症。在目标2中，我将研究INY-03-041诱导的AKT 在体内降解，以确定AKT消耗是否可以是可行的治疗方式。总而言之，这一提议 目的是研究AKT降解的功能后果，并使用INY-03-041作为化学探针 研究急性AKT耗竭的影响。拟议的研究不仅是基于发现，但强调了一个 新的方法来解码在人类癌症中控制AKT信号传导的多效性机制。

Abstract The serine/threonine kinase AKT is a central component of the phosphoinositide 3-kinase (PI3K) signaling pathway and a key regulator of many cellular processes including cell growth, proliferation, and metabolism. Aberrant activation of the PI3K/AKT pathway disrupts normal regulation of proliferation and survival, resulting in tumorigenesis. AKT is hyperactivated in over 50% of human tumors, making it one of the most frequent molecular perturbations in cancer. Several ATP-competitive, allosteric, and covalent pan-AKT inhibitors have been developed and are currently under clinical investigation. However, robust therapeutic responses to AKT inhibition have not been observed. We hypothesized that reducing cellular AKT protein levels via targeted protein degradation could enhance the ability to kill cells dependent on AKT signaling. Heterobifunctional degrader molecules, also known as a PROTACs (proteolysis targeting chimeras), recruit an E3 ubiquitin ligase into close proximity with the target protein to induce its ubiquitination and subsequent proteasomal degradation. We developed INY-03-041, a pan-AKT degrader consisting of the AKT inhibitor, GDC-0068, chemically conjugated to lenalidomide, a recruiter of the E3 ubiquitin ligase Cereblon. Protein degraders display several advantages over inhibitors, including enhancing selectivity of multi-targeted inhibitors, abrogating kinase-independent functions, and overcoming resistance mutations. INY-03-041 induces potent and selective degradation of all three AKT isoforms, and exhibits enhanced anti-proliferative effects compared to GDC-0068 in breast cancer cells. The hypothesis driving this application is that targeted AKT degradation will inhibit cancer cell growth more robustly than AKT inhibition, leading to durable responses in vivo, and will be a valuable tool to identify novel biological functions of AKT. In Aim 1 I will evaluate the consequences of INY-03-041-mediated AKT degradation on cell signaling, proliferation, and survival. The goal of this aim is to uncover novel functions of AKT after acute protein depletion, and to identify genetic or epigenetic biomarkers for sensitivity to AKT degradation, which may inform therapeutic indications for AKT degradation. In Aim 2 I will investigate INY-03-041-induced AKT degradation in vivo to determine if AKT depletion may be a viable therapeutic modality. In summary, this proposal aims to investigate the functional consequences of AKT degradation, and to use INY-03-041 as a chemical probe to study the effects of acute AKT depletion. The proposed studies are not only discovery-based, but highlight a novel method to decode the pleiotropic mechanisms that govern AKT signaling in human cancer.