Discovery of small molecule-mediated protein degradation pathways in human cancer

配体依赖的蛋白质降解已成为一种引人注目的药物控制策略 细胞的蛋白质含量。这一策略具有优势，包括将沉默的“蛋白质结合”小分子 分子转化为蛋白质降解者，这有可能大幅增加可用药物的数量 在癌症等人类疾病中的蛋白质，并以催化的方式操作，可能会降低药物 产生药理作用所需的浓度。尽管如此，直到最近，只有少数人 已发现600多个人类E3连接酶支持这一过程。重要的是，这些E3连接酶 发现表现出明显的和受限的底物特异性，强调需要发现其他 具有差异化性质的可连接E3连接酶，以实现作为一种 药理策略。我们最近利用化学蛋白质组平台和分子生物学 鉴定DCAF16的方法，一个特性不佳的E3连接酶，作为亲电探针的靶标 促进蛋白质的核限制降解。重要的是，DCAF16能够支持配体- 在低参与度(10-40%)时诱导蛋白质降解，这可能使 靶向蛋白质，同时最小限度地干扰其内源底物。在本提案中，通过整合 化学蛋白质组平台利用细胞生物学和分子生物学方法，我计划1)鉴定内源 DCAF16的底物和生物学功能筛选和鉴定破坏癌细胞的小分子 通过接触DCAF16和诱导新底物降解来生长，以及3)发现额外的E3连接酶 在支持配体诱导的靶蛋白的不同癌症类型中具有不同和受限的表达 退化。我的长期目标是为DCAF16和其他 可下药的E3连接酶，并开发药理工具来干预难于下药甚至无法下药的疾病 癌症靶点。拟议的研究将在斯克里普斯研究所进行，该研究所是一家顶级的 研究机构，结合尖端的生物和化学研究，提供独特的交叉 学科科学环境。为了建立一个成功的职业发展和培训计划，我将参加 一系列由TSRI(或UCSD)主办的课程、研讨会和研讨会将全面推进我的 具备指导、教学、科学交流、批判性评估和实验室管理方面的技能。这就做 从本杰明·克拉瓦特博士的指导阶段培训中受益匪浅，他拥有20多年的 蛋白质靶标和化学蛋白质组学小分子抑制剂的开发经验 技术，在癌症转录生物学方面拥有专业知识的Michael Erb博士，以及我的建议 委员会，其中包括杰出的科学家杰弗里·凯利博士和戴尔·博格博士。建议进行的研究 不仅推动了我们对靶向蛋白质降解知识的认识，而且可能是 开发针对癌症中重要但不可用药的蛋白质的新疗法的起点。

Ligand-dependent protein degradation has emerged as a compelling strategy to pharmacologically control the protein content of cells. This strategy has advantages that include converting silent ‘protein-binding’ small molecules to ‘protein degraders’, which has the potential to substantially increase the number of druggable proteins in human disease such as cancer, and to operate in a catalytic manner that may lower the drug concentrations required to produce a pharmacological effect. Nonetheless, until recently, only a handful of the 600+ human E3 ligases have been found to support this process. Importantly, these E3 ligases have been found to show distinct and restricted substrate specificities, underscoring the need to discover additional ligandable E3 ligases with differentiated properties to realize the full scope of targeted protein degradation as a pharmacological strategy. We recently leveraged chemoproteomic platforms and molecular biology approaches to identify DCAF16, a poorly characterized E3 ligase, as a target of electrophilic probes that promotes the nuclear-restricted degradation of proteins. Importantly, DCAF16 is capable of supporting ligand- induced protein degradation at low fractional engagement (10-40%), which may enable the degradation of target proteins while minimally perturbing its endogenous substrates. In this proposal, by integrating chemoproteomic platforms with cell biology and molecular biology approaches, I plan to 1) identify endogenous substrates and biological functions of DCAF16, 2) screen and identify small molecules that disrupt cancer cell growth by engaging DCAF16 and inducing neo-substrate degradation, and 3) discover additional E3 ligases with distinct and restricted expressions in different cancer types that support ligand-induced targeted protein degradation. My long-term goals are to develop potent and selective chemical probes for DCAF16 and other druggable E3 ligases and to develop pharmacological tools to intervene hard-to-drug or even ‘undruggable’ cancer targets. The proposed studies will be carried out at The Scripps Research Institute, a top-ranking research institution which combines cutting edge biological and chemical research to offer a unique cross- disciplinary scientific environment. To build a successful career development and training program, I will attend an array of TSRI- or UCSD-hosted courses, workshops and seminars that will comprehensively advance my skills in mentoring, teaching, scientific communication, critical assessment and laboratory management. I will benefit tremendously from the mentored phase training with Dr. Benjamin Cravatt who has over 20 years of experiences in developing small molecule inhibitors of protein targets as well as chemical proteomic technologies, Dr. Michael Erb who has expertise in transcriptional biology in cancer, and my advisory committee, which includes prominent scientists – Dr. Jeffery Kelly and Dr. Dale Boger. The proposed studies will not only push the boundaries of our knowledge of targeted protein degradation, but may also be the starting point for the development of novel therapeutics targeting important yet undruggable proteins in cancer.