ROR1 as a Therapeutic Target in Acute Lymphoblastic Leukemia

描述(由申请者提供)：候选人：Jeffrey Tyner博士在过去15年里一直在分子和细胞生物学研究领域接受培训，包括暑期学生(普渡大学)、本科生助理(格林内尔学院)、研究生(圣路易斯华盛顿大学)和博士后研究员(俄勒冈健康与科学大学)。他研究过多种生物学领域，包括植物学、免疫学、微生物学和血液学/肿瘤学。这项研究已累计在《自然医学》、《临床调查杂志》、《癌症研究》、《美国国家科学院院刊》、《血液》等高影响力期刊上发表了21篇手稿，以及许多其他正在修改或准备的手稿。泰纳博士还在主要的国家会议上以口头陈述和海报会议的形式展示了他的研究成果。泰纳博士的研究主题涉及确定目标癌基因和癌基因特异性治疗方法，以便为每个患者量身定做癌症治疗方法。为了实现这些目标，他创造了两种筛选技术，利用siRNA或小分子激酶抑制剂来识别功能重要的目标基因，以便后续表征和基因组研究。利用这些技术，他已经确定了一种名为ROR1的基因，该基因是所有1；19染色体易位的急性淋巴细胞性白血病患者的候选治疗靶点。这项建议旨在表征该靶基因过度表达和信号传递的机制，并确定用于治疗干预的基因特异性模式。泰纳博士的长期职业目标包括建立一个独立的研究实验室，专注于癌症研究和个性化医学。 环境：俄勒冈健康与科学大学奈特癌症研究所拥有165名初级教员研究员，他们在不同的调查领域拥有专业知识。泰纳博士的导师布莱恩·德鲁克博士是奈特癌症研究所的主任。德鲁克博士在癌症研究领域有20多年的经验，曾指导过许多学生和研究员成为独立调查员。该提案还包括理查德·古德曼博士、菲利普·斯特里特博士和罗伯特·瑟尔斯博士的支持声明。总体而言，这些支持科学家以及奈特癌症研究所作为一个整体拥有开展本申请中提出的研究所需的所有仪器、资源和专业知识。 研究：用激酶抑制剂特异性靶向致癌信号通路，极大地改善了各种癌症诊断患者的临床结果，尤其是慢性髓系白血病患者。为了将这种靶向治疗方法推广到所有形式的癌症，必须首先识别和表征致病基因。为此，我们开发了一种基于RNAi的筛查，以快速识别直接从白血病患者获得的原代癌细胞中的靶基因。通过这个筛选，我们已经确定了一种受体酪氨酸激酶ROR1，它在t(1；19)阳性的所有急性淋巴细胞白血病(ALL)患者中唯一且一致地过表达，约占所有儿童ALL病例的5%，占成人ALL病例的1-2%。沉默ROR1导致t(1；19)阳性ALL细胞的活性显著降低，但对其他儿童ALL细胞或正常白细胞的活性没有影响。此外，以前对慢性淋巴细胞白血病(CLL)的研究发现，ROR1在大多数病例中过表达。慢性淋巴细胞白血病约占成人白血病病例的30%。要确认ROR1是一个真正的治疗靶点，就必须更好地了解ROR1促进细胞转化的遗传调控和信号机制。然而，对调控ROR1表达的调控元件或ROR1所采用的影响细胞活性的信号通路知之甚少，目前还没有可用的策略来靶向治疗ROR1。在t(1；19)阳性的ALL细胞中发现了ROR1的过度表达和ROR1依赖性，这为研究这一问题提供了独特的工具。我们建议多管齐下地研究1)ROR1表达的调节，2)ROR1促进转化的信号机制，3)抑制ROR1的治疗策略的发展，将阐明ROR1依赖的恶性肿瘤的发病机制，如t(1；19)阳性的ALL或CLL，并为这些患者的治疗干预提供新的策略。 公共卫生相关性：我们发现受体酪氨酸激酶ROR1在t(1；19)阳性的急性淋巴细胞白血病(ALL)患者的细胞上唯一且一致地过表达。ROR1的表达是1；19阳性细胞存活所必需的，使其成为这些患者的新治疗靶点。阐明在t(1；19)阳性ALL中ROR1表达和信号转导的机制将有助于更全面地了解疾病的发病机制，并为治疗干预提供新的策略。

DESCRIPTION (provided by applicant): Candidate: Dr. Jeffrey Tyner has been training in the field of molecular and cellular biology research for the past 15 years as a summer student (Purdue University), undergraduate research assistant (Grinnell College), graduate student (Washington University in St. Louis), and post-doctoral fellow (Oregon Health & Science University). He has studied a diverse spectrum of biological fields including botany, immunology, microbiology, and hematology/oncology. This research has led to 21 cumulative published manuscripts in high-impact journals such as Nature Medicine, Journal of Clinical Investigation, Cancer Research, Proceedings of the National Academy of Science, and Blood as well as numerous other manuscripts in revision or preparation. Dr. Tyner has also presented his work in oral presentations and poster sessions at major national conferences. The theme of Dr. Tyner's research involves the identification of target oncogenes and oncogene-specific therapeutics, such that cancer therapies can be tailored to each individual patient. To accomplish these goals, he has created two screening techniques that make use of siRNA or small-molecule kinase inhibitors to identify functionally important target genes for follow-up characterization and genomic study. Using these techniques, he has identified a gene, ROR1, that is a candidate therapeutic target in all acute lymphoblastic leukemia patients with a 1;19 chromosomal translocation. This proposal aims to characterize the mechanisms of overexpression and signaling of this target gene and to identify gene-specific modalities for therapeutic intervention. Dr. Tyner's long-term career goals include establishment of an independent research lab with a focus on cancer research and personalized medicine. Environment: The Oregon Health & Science University Knight Cancer Institute has 165 primary faculty investigators who have expertise across a diverse spectrum of fields of inquiry. Dr. Tyner's mentor, Dr. Brian Druker, is the Director of the Knight Cancer Institute. Dr. Druker has over 20 years of experience in the field of cancer research and has mentored numerous students and fellows to independent investigator status. This proposal also includes statements of support from Dr. Richard Goodman, Dr. Philip Streeter, and Dr. Robert Searles. Cumulatively, these supporting scientists as well as the Knight Cancer Institute as a whole posses all the instrumentation, resources, and expertise to carry out the research proposed in this application. Research: Specific targeting of oncogenic signaling pathways with kinase inhibitors has vastly improved clinical outcomes for patients with a variety of cancer diagnoses, most notably patients with chronic myeloid leukemia. To expand this targeted-therapy approach to all forms of cancer, disease-causing genes must first be identified and characterized. Towards that end, we have developed an RNAi-based screen to rapidly identify target genes in primary cancer cells obtained directly from leukemia patients. Using this screen, we have identified a receptor tyrosine kinase, ROR1, that is uniquely and consistently overexpressed in all patients with t(1;19)-positive acute lymphoblastic leukemia (ALL), representing approximately 5% of all pediatric ALL and 1-2% of adult ALL cases. Silencing of ROR1 results in significantly decreased viability of t(1;19)-positive ALL cells, but has no effect on viability of other pediatric ALL cells or normal white blood cells. In addition, previous studies of chronic lymphocytic leukemia (CLL), which accounts for approximately 30% of adult leukemia cases, have identified ROR1 overexpression in the majority of cases. Validation of ROR1 as a bona fide therapeutic target necessitates a better understanding of the mechanisms of genetic regulation and signaling by which ROR1 contributes to cellular transformation. However, very little is known about the regulatory elements governing ROR1 expression or the signaling pathways employed by ROR1 to influence cellular viability, and there are currently no available strategies by which ROR1 can be therapeutically targeted. The finding of ROR1 overexpression and ROR1-dependence in t(1;19)-positive ALL cells offers unique tools to study this problem. We propose that a multi-pronged approach to studying 1) regulation of ROR1 expression, 2) signaling mechanisms through which ROR1 contributes to transformation, and 3) development of therapeutic strategies for inhibiting ROR1 will elucidate the disease pathogenesis of ROR1-dependent malignancies such as t(1;19)-positive ALL or CLL and offer new strategies for therapeutic intervention in these patients. PUBLIC HEALTH RELEVANCE: We have found that the receptor tyrosine kinase, ROR1, is uniquely and consistently overexpressed on cells from t(1;19)-positive acute lymphoblastic leukemia (ALL) patients. Expression of ROR1 is required for viability of 1;19-positive cells making it a novel therapeutic target for these patients. Elucidation of the mechanisms underlying ROR1 expression and signaling in t(1;19)-positive ALL will lead to more comprehensive understanding of disease pathogenesis and offer insights into new strategies for therapeutic intervention.