Chemical genetics of LIN-28 in C. elegans

描述（由申请人提供）：秀丽隐杆线虫的lin-28基因编码一种进化上保守的RNA结合蛋白，该蛋白在涉及let-7家族microrna的途径中起作用，控制祖细胞从增生性行为向增生性行为的转变。同样，哺乳动物的LIN-28调节let-7家族microrna的生物发生，也促进干细胞的多能性和增殖行为。LIN-28还在人类癌细胞中Myc致癌信号的下游发挥作用，部分是通过抑制肿瘤抑制因子microrna。因此，LIN-28是开发抗癌治疗药物的可行靶点。由于秀丽隐杆线虫和人类对LIN-28在增殖和多能性中的作用保持一致，因此我们建议将秀丽隐杆线虫作为筛选LIN-28小分子抑制剂的有效且廉价的系统。我们将利用线虫中与LIN-28功能获得相关的显著发育表型来鉴定可以抑制LIN-28活性并抑制这些表型的化合物。我们将利用秀丽隐杆线虫的lin-28通路的良好遗传学来筛选我们的药物，这些药物直接影响蠕虫体内的lin-28蛋白，因此最有可能在人类细胞中发挥类似的作用。我们的主要目标是建立秀丽隐杆线虫系统对LIN-28化学遗传的可行性。同时，我们将通过将促进lin -28靶向药物在临床快速过渡的策略纳入我们的战略措施，进一步最大化项目的潜在回报。因此，利用哺乳动物癌细胞系模型，我们将对我们最初在秀丽隐杆线虫中发现的候选LIN-28抑制剂进行后续测试，以确定其在哺乳动物细胞中的有效性。最重要的是，我们在蠕虫上的筛选将利用fda批准的药物库，因此在秀丽隐杆线虫中发现的抗lin -28药物几乎可以立即用于临床治疗人类癌症。

DESCRIPTION (provided by applicant): The C. elegans lin-28 gene encodes an evolutionarily conserved RNA- binding protein that functions in pathways involving let-7-family microRNAs to control transitions from more proliferative to less proliferative behavior for progenitor cells. Similarly, mammalian LIN-28 regulates the biogenesis of let-7- family microRNAs and also promotes stem cell pluripotency and proliferative behavior. LIN-28 also functions downstream of Myc oncogenic signaling in human cancer cells, in part by inhibiting tumor suppressor microRNAs. Thus, LIN-28 represents a viable target for development of anti-cancer therapeutics. The conservation between C. elegans and humans of the roles for LIN-28 in proliferation and pluripotency prompts us to propose to use C. elegans as an efficient and inexpensive system to screen for small molecule inhibitors of LIN- 28. We will take advantage of the striking developmental phenotypes associated with LIN-28 gain of function in C. elegans to identify compounds that can inhibit LIN-28 activity and suppress those phenotypes. We will leverage the well- developed genetics of the C. elegans lin-28 pathway to triage our drugs for those that directly affect the LIN-28 protein in worms, and hence are most likely to function similarly in human cells. Our main goal is to establish the feasibility of the C. elegans system for chemical genetics of LIN-28. At the same time, we will further maximize the potential payoff from the project by incorporating into our strategy measures that facilitate the rapid transition of LIN-28-targeting drugs in the clinic. Accordingly, using mammalian cancer cell line models, we will perform follow-up tests of candidate LIN-28 inhibitors that we initially identify in C. elegans to establish their efficacy in mammalian cells. Most importantly, our screens on worms will utilize libraries of FDA-approved drugs, and therefore there is the prospect of almost immediate clinical application against human cancer of anti-LIN-28 drugs identified in C. elegans. PUBLIC HEALTH RELEVANCE: LIN-28 plays a major role in regulating the biogenesis of the tumor suppressor miRNAs of the let-7 family and does so downstream of Myc oncogene signaling. LIN-28 therefore represents a potential druggable target in the context of human cancer. We propose to utilize the nematode C. elegans as an in vivo system to efficiently screen for small molecule drugs that can inhibit LIN-28 activity. The chemical compounds the we identify by their inhibition of LIN-28 function in C. elegans will form the basis for further testing of their ability to inhibit LIN-28 in mammalian cancer lines. Since we will include in our screens libraries of FDA-approved drugs, there is the prospect of almost immediate clinical application of anti-LIN-28 drugs that we will identify.