Defining and targeting ER quality control dependence in rhabdomyosarcoma

候选人Sabnis博士是一名儿科肿瘤学家，接受过遗传学和分子生物学方面的培训， 我的目标是领导一个独立的实验室，定义和定位蛋白质稳态中的脆弱性 小儿肉瘤的网络。他已经开始通过第一作者确立自己在这一领域的领导地位 PNAS上的一篇文章详细介绍了横纹肌肉瘤（RMS）中的HSP 70依赖性和贡献作者 发表在《自然医学》和《自然遗传学》上。这个K 08奖将是他的关键工具， 持续的职业发展，提供关键的指导和指导1）设计临床前试验， 使实验室研究的临床转化成为可能，2）探索癌细胞的ER质量控制机制 颠覆，以支持他们的生存，和3）使用遗传操作和细胞生物学读数，以询问 肉瘤生物学中的蛋白质稳态。 环境UCSF是一个杰出的研究环境，拥有1300名主要研究人员和超过500美元的资金。 在NIH的支持下，获得了100万美元（在所有机构中排名第二）。两位共同导师将帮助萨布尼斯博士 他的目标。Trever Bivona博士，医学博士，是一位医学肿瘤学家，在生物学上定义合理的 用于癌基因驱动的实体瘤的综合疗法。Bivona博士拥有广泛的研究支持，包括NIH 创新者奖和几个R 01，并指导了五名博士后研究员进入独立的职位， 过去的五年里Sabnis博士将由Kevin Shannon博士共同指导，医学博士是一名儿科肿瘤学家， 是NCI多个K系列获奖者的主要导师。萨布尼斯博士还将会见半- 每年与一个指导委员会，由Bivona博士组成;香农博士;乔纳森·韦斯曼博士， ER质量控制专家和许多K支持的学员的导师;和Kate Matthay博士，一位杰出的 儿科肿瘤学临床研究员，将支持其发现的临床转化。 Research.高危RMS患者尽管进行了最大程度的强化化疗， 强调了对新的、生物驱动的治疗方法的需求。我们发现抑制胞浆蛋白伴侣 HSP 70在RMS中致命地激活未折叠蛋白反应（UPR），但在其他癌症中不激活。我假设 RMS细胞依赖于HSP 70，与它的辅助分子伴侣DNAJC 17和ATP酶p97一起作用， 通过ER相关降解（ERAD）的ER蛋白负载。因此，RMS中的ERAD抑制定义了一种新的 治疗策略在目标1中，我们将测试两种药物的药理学参数和疗效， 鼠RMS模型中的ER质量控制。在目标2中，我们将鉴定DNAJC 17的结构域， 必要的维持ER稳态，并测试假设，这HSP 70-DNAJC 17-p97轴使 ERAD，从而确保RMS细胞存活。这些目标将提供关键的分子细节， 我们发现了HSP 70抑制的RMS特异性致死性。总的来说，这项工作将促进更广泛的努力， 发现肉瘤蛋白质稳态网络中的治疗靶点，这将是未来R 01提案的基础。 !

Candidate. Dr. Sabnis is a pediatric oncologist with training in genetics and molecular biology whose long-term goal is to lead an independent laboratory defining and targeting vulnerabilities in the protein homeostasis networks of pediatric sarcomas. He has begun to establish himself as a leader in this field through a first author publication in PNAS detailing HSP70 dependence in rhabdomyosarcoma (RMS) and contributing authorship on publications in Nature Medicine and Nature Genetics. This K08 award will be a critical vehicle for his ongoing career development, providing key mentorship and instruction in 1) designing preclinical trials to enable clinical translation of bench research, 2) probing the ER quality control mechanisms cancer cells subvert to support their survival, and 3) using genetic manipulation and cell biologic readouts to interrogate proteostasis in sarcoma biology. Environment. UCSF is an outstanding research environment with 1300 principal investigators and over $500 million in support from the NIH (ranking 2nd among all institutions). Two co-mentors will help Dr. Sabnis achieve his aims. Dr. Trever Bivona, MD PhD, is a medical oncologist with expertise in biologically defining rational polytherapy for oncogene-driven solid tumors. Dr. Bivona has extensive research support including an NIH Innovator’s Award and several R01s, and has mentored five post-doctoral fellows into independent positions in the last five years. Dr. Sabnis will be co-mentored by Dr. Kevin Shannon, MD, a pediatric oncologist who has been the primary mentor for multiple K-series award recipients from the NCI. Dr. Sabnis will also meet semi- annually with a mentoring committee, comprised of Dr. Bivona; Dr. Shannon; Dr. Jonathan Weissman, an expert in ER quality control and mentor to many K-supported trainees; and Dr. Kate Matthay, a pre-eminent pediatric oncology clinical researcher who will support the clinical translation of his discoveries. Research. High-risk RMS patients have dismal outcomes despite maximally intensified chemotherapy, highlighting a need for new, biology-driven treatments. We found that inhibiting the cytosolic protein chaperone HSP70 lethally activates the unfolded protein response (UPR) in RMS, but not in other cancers. I hypothesize that RMS cells rely on HSP70, acting together with its co-chaperone DNAJC17 and the ATPase p97, to lower ER protein load through ER-associated degradation (ERAD). ERAD inhibition in RMS thus defines a novel therapeutic strategy. In aim 1, we will test the pharmacologic parameters and efficacy of two drugs that disrupt ER quality control in murine RMS models. In aim 2, we will identify the structural domains of DNAJC17 that are necessary to maintain ER homeostasis, and test the hypothesis that this HSP70-DNAJC17-p97 axis enables ERAD and thereby ensures RMS cell survival. These aims will provide crucial molecular detail into the basis of the RMS-specific lethality of HSP70 inhibition we discovered. Overall, this work will catalyze a broader effort to discover therapeutic targets in sarcoma proteostasis network that will be the basis for future R01 proposals. !