融合蛋白CBFβ-SMMHC诱发M4Eo型急性髓系白血病的机制研究

M4Eo型白血病是指伴有嗜酸性粒细胞异常的急性粒单核细胞白血病，16号染色体倒置或易位产生的融合蛋白CBFβ-SMMHC是诱发M4Eo型白血病主要原因。此类型白血病关键作用机制尚不清楚，临床缺乏有效的靶向药物，患者长期生存率不高。深入研究此类白血病的病理机制以期找到有效的靶向治疗手段至关重要。申请人前期已经建立蛋白质谱、基因结合谱和转录谱分析方法，分析并鉴定了CBFβ-SMMHC的基因组结合谱和蛋白相互作用网络，提示其可能从转录调控和信号转导等不同层面诱导白血病发生。本项目将采用多种组学和模式动物结合的研究方法，阐述CBFβ-SMMHC在白血病发病过程中的功能，解析其诱发白血病的具体作用机制。设计并合成靶向CBFβ-SMMHC的PROTAC小分子抑制剂，评估该抑制剂的治疗效果。本项目的顺利实施有望揭示CBFβ-SMMHC诱导造血干细胞恶性转化的分子机制，为靶向药物开发提供新思路。

Myelomonocytic acute myeloid leukemia (M4-AML) is frequently associated with inv(16) (p13q22) or the variant t(16;16)(p13;q22). These result in the fusion of two genes, CBFB at 16q22, which encodes the β subunit of the core binding factor (CBFβ), and the MYH11 gene at 16p13, which encodes the smooth muscle myosin heavy chain (SMMHC). The chimeric gene CBFB, in frame with the 3′ portion of MYH11, results in the production of the chimeric protein CBFβ-SMMHC. Since the mechanism of leukemogenesis by the chimeric CBFβ-SMMHC remains elusive, this type of leukemia lacks effective targeted therapies. Therefore, it is crucial to understand the pathogenesis of CBFβ-SMMHC in M4-AML for development of targeted therapies. Here, using mass spectrometry analysis, Cleavage Under Target and Release using nuclease (CUT&Run) and Transient Transcriptome sequencing (TT-seq), we identified protein-protein interaction network of CBFβ-SMMHC, and found that CBFβ-SMMHC and RUNX1 had different binding sites in the genome and mediate the gene transcription of distinct target genes. Combining various approaches of genomics, transcriptomics, and leukemic mice models, we aimed to investigate the function and mechanism of CBFβ-SMMHC in M4-AML subtype. Besides, we would design PROTAC inhibitors of CBFβ-SMMHC to degrade the chimeric and oncogenic proteins, and evaluate their efficacies in CBFβ-SMMHC leukemia models. In summary, this project will not only reveal the molecular mechanism of CBFβ-SMMHC induced leukemogenesis but also benefit the development of targeted therapeutic strategies for AML treatment.