Determining the role of RALA and RALB in soft tissue sarcoma tumor growth and metastasis

项目总结/摘要 K22申请人Steven Sizemore博士获得了博士学位。在格雷厄姆凯西博士的实验室里， 克利夫兰诊所基金会他的博士论文研究集中在 乳腺癌转移候选人的培训继续作为国防部CDMRP乳房 癌症研究计划支持的博士后研究员在凯斯西储大学。这项工作 专注于识别基底细胞样乳腺癌的分子驱动因素。目前，候选人是一名 俄亥俄州州立大学詹姆斯综合癌症中心（OSUCCC）的高级研究助理。 OSUCCC被美国国家癌症研究所评为“杰出”中心，并提供了一个充满活力和 合作环境，候选人继续朝着他的长期目标进行培训， 成为一所一级研究型大学的终身教职员工。候选人目前的工作，在这方面， 该提案的基础是，确定软组织肉瘤（STS）转移的主要调节因素， 通过OSUCCC的种子赠款提供支持。STS是间充质细胞癌的一个多样化的集合， 起源转移性STS患者的5年生存率低至16%，且几乎没有治疗方法 这些患者的选择。这项研究的长期目标是解决迫切的，未满足的需求， 更好地了解驱动STS转移的关键分子途径，并确定STS的抑制剂。 这些途径来改善晚期STS的治疗选择。为了追求这一目标，候选人 发现磷酸酶亚基PPP 2 R1 B是STS转移的抑制因子， 磷蛋白靶点RALA作为治疗晚期STS的假定可操作靶点。这项建议会 彻底检验RALA和密切相关的RALB是重要的和有针对性的假设 STS肿瘤生长和转移的驱动因子，其至少部分通过以下方式调节STS进展： 控制外泌体的产生。具体目标1：将检测RAL亚型的功能要求， 它们在STS生长和转移中的效应物，通过偶联这些同种型的遗传沉默，在体外和体内 利用特定的相互作用缺陷RAL突变体进行拯救实验。具体目标2：将调查 RAL同种型及其效应物在STS细胞产生外泌体中的基本要求， 确定这些RAL依赖性外泌体是否控制肿瘤生长和转移。具体目标3：将利用 STS细胞系和患者来源的异种移植物，以确定靶向RAL的抑制剂作为 STS的创新治疗方法。成功完成此提案将确定一个重要的可操作 靶向改善晚期STS的治疗，并鉴定调节癌症外泌体的新机制。 该奖项将允许候选人的保护时间需要过渡到他的研究从乳腺癌- 专注于STS转移的未充分研究领域，并获得成为一名 癌症相关外泌体领域的领导者。

Project Summary/Abstract The K22 applicant, Dr. Steven Sizemore, obtained his Ph.D. in the laboratory of Dr. Graham Casey at the Cleveland Clinic Foundation. His dissertation research focused on the fundamental mechanisms underlying breast cancer metastasis. The candidate's training continued as a Department of Defense CDMRP Breast Cancer Research Program supported postdoctoral fellow at Case Western Reserve University. This work concentrated on identifying the molecular drivers of basal-like breast cancer. Currently, the candidate is a Senior Research Associate at The Ohio State University James Comprehensive Cancer Center (OSUCCC). The OSUCCC is ranked by the National Cancer Institute as an “exceptional” center and provides a vibrant and collaborative environment in which the candidate has continued his training towards his long-term goal of becoming tenure-track faculty at a Research I level university. The candidate's current work, on which this proposal is based, centers on identifying the master regulators of soft tissue sarcoma (STS) metastasis and is supported through a seed grant from the OSUCCC. STS is a diverse collection of cancers of mesenchymal origin. The 5-year survival for patients with metastatic STS is a dismal 16% and there are few treatment options for these patients. The long-term objective of this research is to address the urgent, unmet need for a better understanding of the key molecular pathways that drive metastasis in STS and identify inhibitors of these pathways to improve the treatment options for advanced STS. In pursuit of this objective, the candidate identified the phosphatase subunit PPP2R1B as a suppressor of STS metastasis and one of its phosphoprotein targets, RALA, as a putative actionable target for treating advanced STS. This proposal will thoroughly test the hypothesis that RALA, and the closely related RALB, are important and targetable drivers of STS tumor growth and metastasis that regulate STS progression, at least in part, by controlling exosome production. Specific Aim 1: will test the functional requirement of the RAL isoforms and their effectors in STS growth and metastasis in vitro and in vivo by coupling genetic silencing of these isoforms with rescue experiments utilizing specific interaction-deficient RAL mutants. Specific Aim 2: will investigate the essential requirement of the RAL isoforms and their effectors in exosome production by STS cells and determine if these RAL-dependent exosomes control tumor growth and metastasis. Specific Aim 3: will utilize STS cell lines and patient derived xenografts to determine the effectiveness of RAL-targeting inhibitors as innovative treatments for STS. Successful completion of this proposal will identify an important actionable target for improved treatment of advanced STS and identify a novel mechanism regulating cancer exosomes. This award will allow the candidate the protected time required to transition his research from a breast cancer- focus to the understudied field of STS metastasis and acquire the additional training required to become a leader in the field of cancer-associated exosomes.