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

配体依赖性蛋白质降解已经成为一种引人注目的策略，以控制蛋白质的降解。 细胞的蛋白质含量。这种策略的优点包括将沉默的"蛋白结合"小分子 分子到“蛋白质降解剂”，这有可能大大增加可药用的数量。 蛋白质在人类疾病如癌症中的作用，并以催化的方式发挥作用， 产生药理作用所需的浓度。尽管如此，直到最近，只有少数 已经发现600多种人E3连接酶支持该过程。重要的是，这些E3连接酶已经被 发现显示出不同的和限制性的底物特异性，强调需要发现额外的 具有差异化特性的可配体E3连接酶，以实现靶向蛋白质降解的全范围， 药理学策略我们最近利用化学蛋白质组学平台和分子生物学 鉴定DCAF16（一种表征不佳的E3连接酶）作为亲电子探针靶点的方法， 促进蛋白质的核限制性降解。重要的是，DCAF16能够支持配体- 在低结合分数（10 - 40%）下诱导蛋白质降解，这可能使 靶向蛋白质，同时最小限度地干扰其内源性底物。在本提案中，通过整合 化学蛋白质组学平台与细胞生物学和分子生物学方法，我计划1）确定内源性 DCAF16的底物和生物学功能，2）筛选和鉴定破坏癌细胞的小分子 通过接合DCAF16并诱导新底物降解来生长，以及3）发现另外的E3连接酶 在不同的癌症类型中具有不同的和受限制的表达，其支持配体诱导的靶向蛋白 降解我的长期目标是为DCAF16和其他药物开发有效和选择性的化学探针。 可药物化的E3连接酶，并开发药理学工具来干预难以药物化甚至"不可药物化的" 癌症靶点拟议中的研究将在斯克里普斯研究所进行，该研究所是一个一流的研究机构。 研究机构，结合尖端的生物和化学研究，提供一个独特的交叉， 科学的环境。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TSRI-或UCSD主办的课程，研讨会和研讨会，将全面推进我的 指导、教学、科学交流、批判性评估和实验室管理方面的技能。我会 从本杰明·克拉瓦特博士的指导阶段培训中受益匪浅，他有超过20年的 在开发蛋白质靶点的小分子抑制剂以及化学蛋白质组学方面的经验 技术，Michael Erb博士，他在癌症转录生物学方面具有专业知识，我的顾问 委员会，其中包括著名的科学家-博士杰弗里凯利和博士戴尔博格。拟议的研究 这不仅将推动我们对靶向蛋白质降解的认识， 这是开发针对癌症中重要但不可治疗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.