目前大部分急性髓系白血病（AML）患者化疗耐药机制不明，是AML治疗中的重要挑战。化疗耐药的根源为高度异质的AML细胞群体在药物作用下驱动耐药亚群的产生或膨胀。我们前期单细胞组学分析发现，同一患者体内有多个细胞亚群携带白血病关键基因PTPN11突变，这些亚群有各自的转录组特征，并且对化疗敏感度不同。我们据此提出关键突变协同其他基因组变异共同介导白血病细胞亚群耐药的假说。本项目拟收集化疗后未完全缓解（NR/PR）的AML患者样本，通过单细胞转录组与基因组测序鉴定化疗作用下优势膨胀或不能被清除的潜在耐药细胞亚群，进一步寻找特异的表面抗原分选候选耐药亚群及前期发现的PTPN11异质性功能群体进行功能鉴定，最后通过测序结合功能实验明确耐药亚群的特征性基因组变异，发现逆转耐药的新靶标。该研究将首次通过解析AML异质性亚群化疗前后的变化，揭示AML耐药机制并发现逆转耐药的关键分子，具有重要的临床意义。

The mechanism of chemo-resistance in most patients with acute myeloid leukemia (AML) remains unknown, which is a major challenge in the treatment of AML. Highly heterogeneous AML cells are driven by selective pressure of chemotherapeutic drugs, leading to the emergency or expansion of drug-resistant subpopulation, and finally cause chemo-resistance. In our preliminary single-cell omics data, the key leukemia-associated gene PTPN11 were found mutated in different tumor cell subpopulations. Those cell subpopulations have their own transcriptome signature as well as different chemotherapeutic drug sensitivity. Therefore, we hypothesis that the key mutation cooperated with other genetic variants mediating chemo-resistance of the leukemia subclone. In this project, the bone marrow samples of AML patients who have not achieved complete remission (NR/PR) after chemotherapy will be collected, and single-cell transcriptome combined with targeted genome sequencing will be performed to identify potential drug-resistant cell subpopulations that expand or fail to be eliminated after chemotherapy. Specific surface markers will be explored to purify the candidate drug-resistant cell subpopulations, as well as the heterogeneous functional PTPN11 subclones we already found, for further functional experiments. Finally, in vitro functional study combined with high-throughput sequencing will be used to confirm the characteristic genetic variants of drug-resistant subpopulations, and investigate novel molecular targets that could reverse drug-resistance. This study will uncover the in vivo changes of heterogeneous AML subpopulations before and after chemotherapy for the first time, reveal the mechanism of AML resistance and offer key targets, which is of great clinical significance.