小分子SBF-1以PTP1B/Bcr-Abl相互作用为靶标的治疗TKI耐药CML新机制

前期研究发现小分子SBF-1具有阻断 PTP1B/Bcr-Abl相互作用，靶向Bcr-Abl降解的作用特点。本研究拟用多种方法证实SBF-1对PTP1B与Bcr-Abl互作的阻断作用，在此基础上明确SBF-1靶向Bcr-Abl降解的选择性和作用强度，并考察其克服CML TKI耐药的作用方式。进一步采用计算机模拟、蛋白截短法、关键氨基酸点突变等确定SBF-1与PTP1B和/或Bcr-Abl的结合位点；用SPR、MST等考察SBF-1阻断PTP1B/Bcr-Abl互作的构效关系；运用免疫共沉淀、iTRAQ等确定SBF-1导致Bcr-Abl持续磷酸化的Tyr位点及其招募的泛素化相关分子，并探讨Bcr-Abl泛素化修饰后进入溶酶体降解的细胞分子过程。最后，在细胞模型、小鼠模型以及临床血样上考察促使Bcr-Abl降解对治疗CML并克服TKI耐药的治疗学意义，为克服伊马替尼类TKI耐药提供新策略。

Our previous study has revealed that small molecule SBF-1 selectively induces Bcr-Abl degradation by blocking the interaction between PTP1B and Bcr-Abl. In this study, we will confirm the blockade of such an interaction by a series of approaches, determine the selectivity and intensity of its triggering Bcr-Abl degradation, and examine the action mode of overcoming TKI resistance in CML by SBF-1. Furthermore, we will examine the structural properties of SBF-1 binding to PTP1B and / or Bcr-Abl , characterizing the binding sites by using computer docking, truncated peptides, and amino acid mutations and analyzing the structure-activity relationship by using SPR, MST. Also, we will identify the phosphorylated Tyr site in Bcr-Abl and the recruited ubiquitination-asscociated molecules upon the blockade of the interaction between PTP1B and Bcr-Abl by SBF-1, and clarify the mechanism of Bcr-Abl degradation in lysosomes. Finally, we will determine the therapeutic effects of SBF-1-induced Bcr-Abl degradation in cell and animal models, as well as clinic samples from TKI-resistant CML patients, and highlight a novel strategy of targeting Bcr-Abl degradation in TKI-resistant CML therapy.