PKC亚型异常表达介导慢性粒细胞白血病对酪氨酸激酶抑制剂耐药的机制研究

Resistance to tyrosine kinase inhibitors(TKI) plays a crucial role in development of relapse and refractory chronic myeloid leukemia(CML). Because of the complex and unclear mechanism, it always lacks of solving strategy in clinic. Recently, abnormal expression of PKC isoforms was found to be associated with leukemic drug-resistance. Herein, we aim to deeply explore the effects and mechanism of different PKC isotypes expressed in CML cells(including leukemia stem cells, pre-mature cells and cell lines) and the microenvironment around it on TKI-tolerance in CML. The preliminary results showed that: ①Overexpression of PKC-β was related with TKI-resistance. And its mechanism was associated with ALOX5 upregulation. ②PKC-θ was overexpressed in bone marrow-derived stromal cells(BMSCs), and it promoted secrection of SDF-1. In the following experiments, we propose to deeply illuminate the molecular mechanism of PKC-β overexpression in TKI-resistance in relapse and refractory CML by PCR ARRAY assay, the second generation sequencing and co-immunoprecipitation and so on. Meanwhile, we'll construct two types of CML mice model to identify that PKC-βand PKC-θ are potent targets to reverse TKI-resistance. Our study will provide a therapeutic strategy to overcome relapse and refractory CML in clinic.

酪氨酸激酶抑制剂（TKI）耐药是导致慢性粒细胞白血病复发难治的关键。因其机制复杂而不明确，临床缺乏解决对策。近年来，多种PKC亚型异常表达被发现与白血病耐药有关。本课题以CML细胞(CML干细胞、亚成熟细胞、细胞株）与其生存的骨髓微环境为载体，探索不同PKC亚型对TKI耐药的影响与机制。初步结果表明： ①PKC-β在CML细胞中高表达与TKI耐药相关，并首次证实其机制可能由上调ALOX5表达介导。②证明PKC-θ在耐药CML患者的骨髓基质细胞（BMSCs）中过表达，并可促进趋化因子SDF-1分泌。在后续实验中，我们拟采用PCR ARRAY、二代测序、免疫共沉淀等方法深入探讨PKC-β和PKC-θ介导CML对TKI耐药的分子机制；并建立CML小鼠移植瘤模型，从体内验证PKC-β和PKC-θ可作为逆转TKI耐药的潜在靶点，为临床克服复发难治型CML提供新的治疗策略。

酪氨酸激酶抑制剂（TKI）耐药是导致慢性粒细胞白血病复发难治的关键。因其机制复杂而不明确，临床缺乏解决对策。近年来，多种PKC亚型异常表达被发现与白血病耐药有关。本课题以CML细胞(CML干细胞、亚成熟细胞、细胞株）与其生存的骨髓微环境为载体，探索不同PKC亚型对TKI耐药的影响与机制。初步结果表明： ①PKC-α高表达可以通过提高G2/M期促进CML细胞增殖并对TKI耐药；②PKC-β在CML细胞中高表达与TKI耐药相关，并首次证实其机制可能由上调ALOX5表达介导。③PKC-θ在CML细胞中高表达可以促进耐药相关因子——血管生成素1（ANG-1）高表达，分泌至骨髓微环境中ANG-1可以促进骨髓间充质干细胞（BMSC）朝向肿瘤相关成纤维细胞转化，从而介导TKI耐药。此外，项目组还构建了CML小鼠移植瘤模型，从体内验证PKC-α和PKC-β可作为逆转TKI耐药的潜在靶点，为临床克服复发难治型CML提供新的治疗策略。