小分子抑制剂JNJ-165通过非ATP竞争性结合机制对BCR/ABL的抑制作用研究

Chronic myeloid leukemia (CML) is a common malignant disease derived from hematopoietic stem cell. In the last 15 years, the targeted therapy of tyrosine kinase inhibitors (TKIs) achieved great success, but nearly 35% of the patients would be drug-resistance, and the other patients, although achieved molecular genetics remission, the minimal residual disease of BCR/ABL persisted. Importantly, the effects of TKIs on accelerated and blastic phase of CML are poor. Recent research shows that, CML exists leukemia stem cell(LSC), which also expresses BCR/ABL protein. TKIs as ATP-competitive inhibitors have no effect on the CML LSC BCR/ABL fusion gene. CML LSC is the source of CML disease progression and recurrence. The ATP-competitive independent pathway of degrading BCR/ABL protein may be an effective approach to overcome this limitation. Our previous study of small molecule inhibitor JNJ-165 showed that it down-regulated BCR/ABL of T315I mutation, and we hypothesize that the molecular mechanism of JNJ-165 may be an ATP-competitive independent pathway, which also have the inhibitory effect on LSC BCR/ABL. In this study, we will investigate the mechanism of JNJ-165 from the aspects of transcription, translation and protein degradation of BCR/ABL.

慢性粒细胞白血病（CML）是血液系统常见的恶性肿瘤，酪氨酸激酶抑制剂（TKI）靶向治疗CML取得了很大的成功，但近35%的患者会发生耐药，另一部分患者虽然分子遗传学缓解，但BCR/ABL的残留病灶持续存在，并且TKI对加速期及急变期CML疗效差。研究表明，CML存在白血病干细胞（LSC），其也表达BCR/ABL，大多数TKI作为ATP竞争性抑制剂对CML LSC的BCR/ABL没有作用，是CML疾病进展、复发的根源。非ATP竞争性的BCR/ABL抑制途径可能是克服这种局限性的重要新方法。我们前期工作发现小分子抑制剂JNJ-165显著下调TKI全耐药具有T315I位点突变的BCR/ABL，且不依赖p53通路，推测其抑制BCR/ABL的机制为非ATP竞争性结合途径，可能对LSC BCR/ABL具有降解作用，我们将从转录、翻译及蛋白降解等方面阐明其分子机制。

慢性粒细胞白血病（CML）是血液系统常见的恶性肿瘤，酪氨酸激酶抑制剂（TKI）靶向治疗CML取得了很大的成功，但近35%的患者会发生耐药，另一部分患者虽然分子遗传学缓解，但BCR/ABL的残留病灶持续存在，并且TKI对加速期及急变期CML疗效差。研究表明，CML存在白血病干细胞（LSC），其也表达BCR/ABL，大多数TKI作为ATP竞争性抑制剂对CML LSC的BCR/ABL没有作用，是CML疾病进展、复发的根源。非ATP竞争性的BCR/ABL抑制途径可能是克服这种局限性的重要新方法。我们前期工作发现小分子抑制剂JNJ-165显著下调TKI全耐药具有T315I位点突变的BCR/ABL，且不依赖p53通路，推测其抑制BCR/ABL的机制为非ATP竞争性结合途径，可能对LSC BCR/ABL具有降解作用。本项目从BCR/ABL的启动子、转录、翻译、蛋白降解各个水平阐明其下调BCR/ABL的分子机制，发现JNJ-165不仅能从转录水平上下调BCR/ABL基因的表达，而且能通过激活PP2A/SHP-1通路使得BCR/ABL去磷酸化，最终通过蛋白酶体和自噬溶酶体途径降解BCR/ABL，具有不同于TKIs通过ATP竞争性结合抑制BCR/ABL激酶活性的特点。并且通过体内研究，发现JNJ-165能够增强传统TKIs的疗效，对于提高TKIs耐药CML患者的疗效及改善预后，尤其对于BCR/ABL突变耐药的CML具有重要的理论意义和应用前景。. 本项目实施至今，作为第一作者（或共同第一）及第一作者单位在国际专业刊物发表SCI论文7篇。发表SCI影响因子（IF）较高的论文有Journal of hematology & oncology（IF6.263）、Journal of Experimental & Clinical Cancer Research（IF6.217）各1篇。以该课题为重要成果已分别获得浙江省医药卫生科技奖一等奖、浙江省科技进步二等奖各1项。在本项目基础上进一步获得国家自然科学基金面上项目资助1项。