"Oncorequisite" Genes in MYC-mediated Transformation

描述(申请人提供)：MYC是一种有效的原癌基因，在包括白血病和淋巴瘤在内的人类癌症中广泛异常表达。这项提议的长期目标是发现维持MYC驱动的肿瘤，特别是T细胞急性淋巴细胞白血病(T-ALL)所必需的分子，因此可能成为开发新的分子疗法的有用靶点。使用转基因斑马鱼模型，在该模型中，小鼠Myc在胸腺细胞中表达并可靠地产生T细胞白血病，我计划进行显性遗传修饰筛选，以识别和研究其突变延迟白血病发病的“癌必需”基因(目标1和2)，然后阐明这些基因的人类同源基因在T-ALL和神经母细胞瘤病理生理学中的重要性，包括它们被抑制的后果(目标3)。我最近的初步数据很好地说明了这种方法的原理和可行性，因为我最近的初步数据定位了编码二氢硫胺S琥珀酰基转移酶(DLST)的特定基因，该基因的杂合失活显著延迟了表达MYC癌基因的斑马鱼淋巴瘤/白血病的发生。α-酮-对甲基-n-戊酸(KMV)对cc-酮-谷氨酸脱氢酶复合体(DLST是pound2组分)的小分子抑制作用促进了斑马鱼淋巴瘤/白血病的快速消退，并显著降低了人ALL细胞系的存活率。因此，我认为这个Kreb循环转移酶的人类同源基因是一种有希望的候选“癌必需”蛋白，用于进一步表征和测试人类恶性肿瘤的现有抑制剂。在斑马鱼中使用无偏见的正向遗传策略，将避免对MYC诱发癌症的致癌基因和途径的先验知识--这一创新使这一应用有别于该领域的其他应用--这样，我发现的任何抑制突变都将自动成为小分子或单抗抑制的潜在有用靶点。 相关性：许多人类癌症依靠MYC癌基因的表达来支持。通过在FISH中识别可以延缓Myc驱动的T细胞白血病发病的突变基因，该项目试图发现可以作为人类癌症治疗干预有用靶点的分子。

DESCRIPTION (provided by applicant): MYC, a potent proto-oncogene, is aberrantly and widely expressed in human cancers, including the leukemias and lymphomas. The long-term goal of this proposal is to discover molecules that are necessary to sustain MYC-driven tumors, T-cell acute lymphoblastic leukemia (T-ALL) in particular and hence might serve as useful targets for the development of novel molecular therapeutics. Using a transgenic zebrafish model in which murine Myc is expressed in thymocytes and reliably generates T-cell leukemia, I plan to conduct a dominant genetic modifier screen to identify and study "oncorequisite" genes whose mutation delays the onset of leukemia (Aims 1 and 2) and then to clarify the importance of the human orthologs of these genes in T-ALL and neuroblastoma pathophysiology, including the consequences of their inhibition (Aim 3). The rationale and feasibility of this approach are well-illustrated by my recent preliminary data pinpointing a specific gene, encoding dihydrolipoamide S-succinyltransferase (DLST), whose heterozygous inactivation significantly delayed the onset of lymphoma/leukemia in zebrafish expressing the MYC oncogene. Small molecule inhibition of the cc- ketoglutatate dehydrogenase complex (DLST is an pound2 component) by a-keto-p-methyl-n valeric acid (KMV) promoted the rapid regression of zebrafish lymphoma/leukemia, and significantly decreased the viability of humanT-ALL cell lines. Hence, I consider the human ortholog of this Kreb's cycle transferase a promising candidate "oncorequisite" protein for further characterization and testing with available inhibitors in human malignancies. The use of unbiased forward genetic strategies in the zebrafish will circumvent the need for a priori knowledge of contributing genes and pathways in MYC-induced cancer -an innovation that sets this application apart from others in the field - so that any suppressor mutant I identify will automatically qualify as a potentially useful target for inhibition with small molecules or monoclonal antibodies. RELEVANCE: Many human cancers rely on expression of the MYC oncogene for their support. By identifying mutant genes that delay the onset of Myc-driven T-cell leukemia in fish, this project seeks to discover molecules that could serve as useful targets for therapeutic intervention in human cancers.