Combinatorial Targeting of the Cell Cycle and Key Interacting Pathways in Mesothelioma

问题：间皮瘤是一种毁灭性的癌症，大多数患者会死于这种疾病。 间皮瘤化疗的最后一个重大进展是培美曲塞，它被FDA批准 2004年绝大多数间皮瘤肿瘤在细胞周期中有缺陷。低表达 CDK 4/CDK 6抑制剂p16 INK 4a已在间皮瘤的多项基础和临床研究中得到证实。一 一项III期研究报告，接受palbociclib治疗的乳腺癌患者的生存率显著增加， 选择性CDK 4/6抑制剂。间皮瘤肿瘤还表现出PI 3 K/MTOR通路的激活，以及PI 3 K/MTOR通路的抑制。 已经证明PI 3 K/MTOR克服乳腺癌细胞中的CDK 4/6抑制剂抗性。一 通过线粒体抗氧化防御蛋白减少活性氧（ROS）在细胞凋亡中起关键作用。 间皮瘤细胞克服ROS诱导的促凋亡信号传导的能力。 需要解决的知识：该实验室的长期目标是确定癌症的关键原则 生物学，这将允许适当选择最有效的组合疗法的基础上，前期 分子特征作为追求这一长期目标的下一步，本申请的目的是 确定靶向CDK 4/6如何与抑制CDK 2、PI 3 K/MTOR或 线粒体抗氧化防御在间皮瘤的治疗。结果将与mRNA相关 表达签名，其可以应用于为患者选择治疗组合。 假设：我们的中心假设是CDK 4/6的抑制与CDK 2的抑制相结合， PI 3 K/MTOR或线粒体抗氧化防御将导致多种不同分子亚型的细胞死亡 间皮瘤 初步研究：我们已经证明，间皮瘤细胞增殖可以通过细胞周期蛋白， D1敲低和CDK 4/6的小分子抑制。我们还证明了龙胆紫（已知 抑制抗氧化防御）以协同方式使间皮瘤细胞对palbociclib敏感。 具体目标：1）确定CDK 4/6促进间皮瘤细胞存活的机制， 对CDK 4/6抑制的抗性是否因分子亚型而异，并确定是否同时 与单独抑制CDK 4/6相比，抑制CDK 2具有协同益处。2)通过以下方式定义机制： 其中PI 3 K/MTOR克服细胞周期抑制，并确定如何同时抑制 CDK 4/6和PI 3 K/MTOR在间皮瘤中因分子亚型而异。3)确定机制， 单独或联合抑制线粒体抗氧化防御和CDK 4/6影响线粒体 间皮瘤细胞的功能和调节细胞死亡。 意义和创新：拟议的工作是创新的，因为它利用了对代理人的评估， 他们的能力，影响细胞周期，PI 3 K/MTOR，或抗氧化防御组合在间皮瘤的基础上， 已知对治疗难治的癌症中的分子谱分析。根据间皮瘤的基因组图谱， 使用细胞周期抑制作为联合治疗的组分应该是理想的。这项研究将奠定 细胞周期抑制剂如何与CDK 2、PI 3 K/MTOR或 线粒体抗氧化防御这项工作的一个非常积极的转化影响是，它将为设计提供信息， 用于测试CDK 4/6抑制剂与其他活性抗癌药物组合的临床试验。

The Problem: Mesothelioma is a devastating cancer where the majority of patients will die from their disease. The last significant advance in chemotherapy for mesothelioma was pemetrexed, which was approved by the FDA in 2004. The vast majority of mesothelioma tumors have defects in the cell cycle. Low expression of the CDK4/CDK6 inhibitor p16INK4a has been demonstrated in multiple basic and clinical studies of mesothelioma. A phase III study reported a significant increase in survival in breast cancer patients who received palbociclib, a selective CDK4/6 inhibitor. Mesothelioma tumors also exhibit activation of the PI3K/MTOR pathway, and inhibition of PI3K/MTOR has been demonstrated to overcome CDK4/6 inhibitor resistance in breast cancer cells. A decrease in reactive oxygen species (ROS) by mitochondrial antioxidant defense proteins plays a key role in the ability of mesothelioma cells to overcome the pro-apoptotic signaling induced by ROS. Knowledge to be Addressed: The long-term goal of this laboratory is to identify key principles of cancer biology that will allow the appropriate selection of the most effective combination therapies based on upfront molecular signatures. The objective of this application as a next step in the pursuit of this long-term goal is to determine how targeting CDK4/6 may be exploited in combination with inhibition of CDK2, PI3K/MTOR, or mitochondrial antioxidant defense in the treatment of mesothelioma. Findings will be correlated with mRNA expression signatures that can be applied for to selecting treatment combinations for patients. Hypothesis: Our central hypothesis is that inhibition of CDK4/6 in combination with inhibition of CDK2, PI3K/MTOR, or mitochondrial antioxidant defense will cause cell death for multiple and distinct molecular subtypes of mesothelioma. Preliminary Studies: We have demonstrated that mesothelioma cell proliferation can be decreased via Cyclin D1 knockdown and small molecule inhibition of CDK4/6. We have also demonstrated that gentian violet (known to inhibit antioxidant defense) sensitizes mesothelioma cells to palbociclib in a synergistic fashion. Specific aims: 1) Identify mechanisms by which CDK4/6 contributes to mesothelioma cell survival, determine whether resistance to CDK4/6 inhibition varies by molecular subtype, and determine whether simultaneous inhibition of CDK2 has synergistic benefits compared to inhibition of CDK4/6 alone. 2) Define the mechanism by which PI3K/MTOR overcomes cell cycle inhibition and identify how the effectiveness of simultaneous inhibition of CDK4/6 and PI3K/MTOR in mesothelioma varies by molecular subtype. 3) Identify mechanisms by which inhibition of mitochondrial antioxidant defense and CDK4/6 individually or in combination affect mitochondrial function and regulated cell death in mesothelioma cells. Significance and Innovation: The proposed work is innovative because it capitalizes on evaluation of agents for their ability to affect the cell cycle, PI3K/MTOR, or antioxidant defense in combination in mesothelioma based on molecular profiling in a cancer known to be refractory to therapy. Based on the genomic profile of mesothelioma, using cell cycle inhibition as a component of combination therapy should be ideal. The proposed research will lay a groundwork for how cell cycle inhibitors can be given in combination with inhibitors of CDK2, PI3K/MTOR, or mitochondrial antioxidant defense. A very positive translational impact of this work is that it will inform the design of clinical trials for testing CDK4/6 inhibitors in combination with other active cancer-fighting drugs.