Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, Affiliated Cancer Hospital of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 510120, China; Department of Anesthesiology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China.
Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, Affiliated Cancer Hospital of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 510120, China.
J Ethnopharmacol. 2023 Jan 30;301:115815. doi: 10.1016/j.jep.2022.115815. Epub 2022 Oct 8.
Piper longum L., an herbal medicine used in India and other Asian countries, is prescribed routinely for a range of diseases, including tumor. Piperlongumine, a natural product isolated from Piper longum L., has received widespread attention due to its various pharmacological activities, such as anti-inflammatory, antimicrobial, and antitumor effects.
Chronic myelogenous leukemia (CML) is a hematopoietic disease caused by Bcr-Abl fusion gene, with an incidence of 15% in adult leukemias. Targeting Bcr-Abl by imatinib provides a successful treatment approach for CML. However, imatinib resistance is an inevitable issue for CML treatment. In particular, T315I mutant is the most stubborn of the Bcr-Abl point mutants associated with imatinib resistance. Therefore, it is urgent to find an alternative approach to conquer imatinib resistance. This study investigated the role of a natural product piperlongumine in overcoming imatinib resistance in CML.
Cell viability and apoptosis were evaluated by MTS assay and Annexin V/propidium iodide counterstaining assay, respectively. Levels of intracellular signaling proteins were assessed by Western blots. Mitochondrial membrane potential was reflected by the fluorescence intensity of rhodamine-123. The function of proteasome was detected using 20S proteasomal activity assay, proteasomal deubiquitinase activity assay, and deubiquitinase active-site-directed labeling. The antitumor effects of piperlongumine were assessed with mice xenografts.
We demonstrate that (i) Piperlongumine inhibits proteasome function by targeting 20S proteasomal peptidases and 19S proteasomal deubiquitinases (USP14 and UCHL5) in Bcr-Abl-WT and Bcr-Abl-T315I CML cells; (ii) Piperlongumine inhibits the cell viability of CML cell lines and primary CML cells; (iii) Proteasome inhibition by piperlongumine leads to cell apoptosis and downregulation of Bcr-Abl; (iv) Piperlongumine suppresses the tumor growth of CML xenografts.
These results support that blockade of proteasome activity by piperlongumine provides a new therapeutic strategy for treating imatinib-resistant CML.
荜茇，一种在印度和其他亚洲国家常规用于治疗多种疾病的草药，包括肿瘤。荜茇碱，一种从荜茇中分离出来的天然产物，由于其具有抗炎、抗菌和抗肿瘤等多种药理活性，受到了广泛的关注。
慢性髓性白血病（CML）是一种由 Bcr-Abl 融合基因引起的造血系统疾病，在成人白血病中的发病率为 15%。伊马替尼通过靶向 Bcr-Abl 为 CML 提供了一种成功的治疗方法。然而，伊马替尼耐药是 CML 治疗中不可避免的问题。特别是，T315I 突变是与伊马替尼耐药相关的 Bcr-Abl 点突变中最顽固的一种。因此，迫切需要寻找一种替代方法来克服伊马替尼耐药。本研究探讨了天然产物荜茇碱在克服 CML 伊马替尼耐药中的作用。
通过 MTS 测定和 Annexin V/碘化丙啶复染法分别评估细胞活力和细胞凋亡。通过 Western blot 检测细胞内信号蛋白水平。用罗丹明 123 的荧光强度反映线粒体膜电位。通过 20S 蛋白酶体活性测定、蛋白酶体去泛素化酶活性测定和去泛素化酶活性位点标记检测蛋白酶体的功能。用小鼠异种移植评估荜茇碱的抗肿瘤作用。
我们证明了（i）荜茇碱通过靶向 Bcr-Abl-WT 和 Bcr-Abl-T315I CML 细胞中的 20S 蛋白酶体肽酶和 19S 蛋白酶体去泛素化酶（USP14 和 UCHL5）来抑制蛋白酶体功能；（ii）荜茇碱抑制 CML 细胞系和原代 CML 细胞的细胞活力；（iii）荜茇碱抑制蛋白酶体导致细胞凋亡和 Bcr-Abl 下调；（iv）荜茇碱抑制 CML 异种移植的肿瘤生长。
这些结果支持通过荜茇碱阻断蛋白酶体活性为治疗伊马替尼耐药的 CML 提供了一种新的治疗策略。
