Overcoming drug resistance using small molecule activators of protein phosphatase 2A

使用蛋白磷酸酶 2A 小分子激活剂克服耐药性

基本信息

批准号：
10513191
负责人：
JENNIFER D. BLACK
金额：
$ 22.9万
依托单位：
UNIVERSITY OF NEBRASKA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-03 至 2024-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10513191
关键词：
Address Autophagocytosis Biological Breast Cancer Patient CDK2 gene CDK4 gene CRISPR/Cas technology Cancer cell line Cell Cycle Cell Cycle Progression Cell Cycle Proteins Cell Line Cell Proliferation Cell Survival Cells Chemoresistance Clinic Clinical Trials Complex Cyclin D1 Cyclin-Dependent Kinase Inhibitor Cyclins DNA Down-Regulation Drug resistance FDA approved G1 Phase Genetic Genetic Transcription Genotoxic Stress Head and Neck Squamous Cell Carcinoma Holoenzymes Human Immunodeficient Mouse Investigation Knock-out Link Maintenance Malignant Neoplasms Mediating Mitogens Mus Mutation Nature Non-Small-Cell Lung Carcinoma Normal Cell Oncogenic Organoids Patients Pharmaceutical Preparations Pharmacology Pharmacy (field)Phenotype Protein Phosphatase 2A Regulatory Subunit PR53 Protein phosphatase Proteins Proteolysis Publishing Rattus Research Personnel Resistance Role Seminal Signal Transduction Testing Therapeutic Toxic effect Translations Tumor Suppression Tumor Suppressor Proteins Ubiquitin Up-Regulation Xenograft procedure anti-cancer antitumor agent antitumor effect base cancer cell cancer type cell type follow-up genome-wide in vivo Model in vivo evaluation inhibitor mRNA Stability melanoma mouse model multicatalytic endopeptidase complex neoplastic cell novel novel therapeutics nutrient deprivation overexpression preclinical study protein complex resistance mechanism response retinoblastoma tumor suppressor sensor small molecule targeted cancer therapy therapeutic target tumor tumorigenesis ubiquitin-protein ligase uncontrolled cell growth

项目摘要

Uncontrolled cell proliferation resulting from aberrant activity of cell cycle proteins is a hallmark of cancer. Overexpression of the mitogen sensor cyclin D1 is among the most frequent abnormalities in tumors, enhancing the activity of cyclin dependent kinases 4 and 6 (CDK4/6) to drive G1→S phase progression and promote cell survival and chemoresistance. Increased expression of D-type cyclins is required not only for tumorigenesis but also for tumor maintenance and progression. Thus, aberrant cyclin D-CDK4/6 activity represents an actionable target for cancer therapy and D-type cyclin function is among the top therapeutic targets for cancer management. Inhibitors of CDK4/6 activity have shown promise in the clinic and palbociclib, abemaciclib, and ribociclib are FDA-approved for use in patients. Several hundred clinical trials are currently ongoing to evaluate the antitumor effects of these agents in a broad spectrum of cancer types. However, the therapeutic promise of CDK4/6 inhibitors is dampened by inevitable emergence of resistance. Recent seminal studies have identified a novel mechanism of resistance to these agents mediated by deficiency of autophagy and beclin 1 regulator 1 (AMBRA1), an E3 ligase adaptor and master regulator of cyclin D1, D2, and D3 protein stability. Loss or mutation of AMBRA1 is seen in a significant subset of human cancers, in association with poor patient survival. AMBRA1 deficiency promotes the accumulation of D-type cyclins, a hyperproliferative phenotype, and tumorigenesis, while reducing the sensitivity of tumor cells to all three FDA-approved CDK4/6 inhibitors. Evidence that upregulation of D-type cyclins and the formation of non-canonical cyclin D-CDK2 and p27-cyclin D-CDK4 complexes underpins resistance to these agents forms the basis of this proposal. Strategies are proposed to explore the mechanism-driven application of Small Molecule Activators of PP2A (SMAPs) for overcoming resistance to CDK4/6 inhibitors in the context of AMBRA1 deficiency. SMAPs are a novel class of antitumor agents that selectively activate a subset of PP2A holoenzymes for potent tumor suppression in a variety of cancer types. This project builds on our discovery that SMAPs potently downregulate cyclins D1, D2 and D3 in all cell types tested. Importantly, SMAPs act as AMBRA1-independent D-type cyclin ‘degraders,’ promoting rapid proteolysis of these molecules via a proteasome-dependent mechanism that remains functional following loss of AMBRA1. Based on these findings, we hypothesize that combining CDK4/6 inhibitor treatment with a SMAP ‘D-type cyclin degrader’ will enhance antitumor activity and reverse resistance to CDK4/6 inhibitors driven by AMBRA1 deficiency. Proof-of-concept studies will be performed in two Specific Aims: (1) Explore the effects of combining CDK4/6 inhibitors and SMAPS in the context of AMBRA1-deficiency, and (2) Evaluate the effects of SMAP- CDK4/6 inhibitor combinations in tumor models in vivo. Importantly, in addition to addressing consequences of AMBRA1-deficiency, our proof-of-concept findings are anticipated to be broadly applicable to tumors harboring increased levels of D-type cyclins and aberrant CDK activity resulting from other tumor-associated alterations.

细胞周期蛋白异常活性导致的不受控制的细胞增殖是癌症的标志。有丝分裂原传感器Cyclin D1的过表达是肿瘤中最常见的异常之一，增强细胞周期蛋白依赖性激酶4和6（CDK4/6）的活性驱动G1→S相进展并促进细胞生存和化学抗性。 D型细胞周期蛋白的表达不仅需要用于肿瘤发生，还需要也用于肿瘤维持和进展。那就是异常的细胞周期蛋白D-CDK4/6活性代表可操作的癌症治疗和D型细胞周期蛋白功能的靶标是癌症管理的最佳治疗靶标之一。 CDK4/6活性的抑制剂在诊所和palbociclib，abemaciclib和ribociclib中表现出了希望 FDA批准用于患者。目前正在进行数百次临床试验来评估抗肿瘤这些药物在广泛的癌症类型中的影响。但是，CDK4/6的治疗承诺抑制剂是由于不可避免的抗性出现而诅咒的。最近的第二项研究已经确定了一项小说自噬和Beclin 1调节器1介导的对这些药物的抗性机制1 （AMBRA1），Cyclin D1，D2和D3蛋白稳定性的E3连接酶适配器和主调节剂。损失或突变在人类癌症的大部分子集中可以看到AMBRA1的生存率差。 Ambra1 缺乏促进D型细胞周期蛋白的积累，一种过度增殖表型和肿瘤发生，而肿瘤发生降低了肿瘤细胞对所有三种FDA批准的CDK4/6抑制剂的敏感性。更新的证据 D型细胞周期蛋白以及非典型细胞周期蛋白D-CDK2和P27-Cyclin D-CDK4复合物的形成基础对这些代理的抵抗是该提案的基础。提出了策略来探索机理驱动的PP2A小分子激活剂（SMAP）的应用以克服对在AMBRA1缺乏症的情况下，CDK4/6抑制剂。 SMAP是一类新型的抗肿瘤剂，选择性地激活PP2A全酶的一部分，以在多种癌症类型中抑制有效的肿瘤。该项目建立在我们的发现基础上，该发现可能会在所有细胞类型中都可能下调细胞周期蛋白D1，D2和D3 测试。重要的是，SMAP充当AMBRA1独立的D型细胞周期蛋白“降解器”，促进快速蛋白水解这些分子通过蛋白酶体依赖性机制，该机制在AMBRA1丢失后保持功能性。基于这些发现，我们假设将CDK4/6抑制剂治疗与SMAP'D型细胞周期蛋白结合 DEGRADER’将增强抗肿瘤活性和对CDK4/6抑制剂的反向抗性不足。概念证明研究将以两个具体的目的进行：（1）探索组合的影响在AMBRA1缺乏性的情况下，CDK4/6抑制剂和SMAP，（2）评估SMAP-的影响体内肿瘤模型中的CDK4/6抑制剂组合。重要的是，除了解决 AMBRA1缺陷，我们的概念验证发现预计将广泛适用于携带的肿瘤由其他肿瘤相关的改变引起的D型细胞周期蛋白和异常CDK活性的水平增加。