急性髓系白血病（Acute myeloid leukemia，AML）约占儿童急性白血病的15%～20%，疗效远低于儿童急性淋巴细胞白血病。化疗药物耐药是儿童AML难治复发的主要原因。高三尖杉酯碱（Homoharringtonine, HRT）是由我国科研工作者从高三尖属植物中分离而来，并在大量临床实践中形成了以HRT为基础的化疗方案。然而，目前对于HRT的耐药机制尚不清楚，揭示其耐药机制对指导HRT在复发/难治的儿童AML的化疗应用具有重要的意义。本项目拟利用CRISPR/Cas9文库和高通量测序技术，结合临床初治缓解和难治/复发病例的多组学测序结果，筛选可引起HRT化疗耐药的基因和信号通路，并利用体外模型进行验证，以探索HRT在儿童AML化疗中的耐药机制，利用体内外模型筛选和验证可逆转HRT耐药的靶向小分子化合物，为靶向治疗难治/复发的儿童AML提供解决方案。

Acute myeloid leukemia (AML) accounts for 15%-20% of pediatric acute leukemia, and its prognosis is much worse than that of pediatric acute lymphoblastic leukemia. Drug resistance is the main cause for its relapse and refractoriness. Homoharringtonine (HRT) is a commonly used chemotherapeutic drug which was isolated from high tricus genus by Chinese researchers, and multiple HRT-based chemotherapy regimens have been established from long-term clinical practice to promote the prognosis of AML. Despite its wide clinical use, very little research has been done to explore HRT resistance in AML treatment. Revealing the underlying mechanisms in HRT resistance is of great significance in guiding its application in relapsed and refractory pediatric AML treatment. Our project intends to use CRISPR/Cas9 library and high-throughput sequencing strategy，combined with the results of multi-group sequencing of clinical initial remission cases and refractory/relapsed cases, to screen for genes and pathways that may play roles in HRT chemoresistance, and validate the functions of candidate genes and pathways in vitro models; furthermore to screen for targeted small molecule compounds which could reverse HRT resistance in vitro models and then test the effect in PDX mouse models, thus provide solutions for targeted treatment of relapsed and refractory pediatric AML.