对阿霉素（DOX）的耐药性极大地限制了其对乳腺癌（BC）患者的治疗效果。 Saikosaponin D (SSD) 是一种从传统草药柴胡中提取的三萜皂苷，由于其显着的抗肿瘤活性，在临床前研究中显示出作为化疗增敏剂的前景。然而，SSD在DOX耐药BC细胞中的作用和机制在很大程度上尚未被探索。本研究旨在研究SSD对DOX耐药BC细胞的体外和体内化学增敏作用及其潜在的分子机制。体外测定，包括进行细胞活力、克隆形成、三维肿瘤球体生长和凋亡分析，以评估 SSD 和 DOX 对耐药 BC 细胞的协同作用。采用活性氧 (ROS)、GSH/GSSG、NADPH/NADP 和 NADH/NAD 检测来评估 SSD 对细胞氧化还原稳态的影响。通过Western blotting、细胞周期分布测定和DOX摄取测定进一步阐明SSD可能的抗肿瘤机制。最后建立裸鼠皮下MCF7/DOX细胞异种移植模型，验证SSD联合DOX的体内抗癌作用。SSD显着抑制细胞活力、增殖和克隆形成，增强DOX的体内外抗癌功效。从机制上讲，SSD 降低了 STAT1、NQO1 和 PGC-1α 蛋白水平，导致细胞氧化还原失衡、ROS 生成过多以及 GSH、NADPH 和 NADH 消耗。 SSD 通过破坏氧化还原稳态来诱导 DNA 损伤，导致 G0/G1 期细胞周期停滞。此外，SSD 通过抑制 P-gp 蛋白表达和外排活性来增加 BC 细胞中 DOX 的积累。我们首次证明，SSD 通过灭活 STAT1/NQO1/ 来破坏细胞氧化还原稳态，从而增强化疗耐药 BC 细胞对 DOX 的敏感性。 PGC-1α信号通路。这项研究为 SSD 作为耐药 BC 治疗的辅助药物提供了证据。版权所有 © 2024 Elsevier GmbH。版权所有。

Drug resistance to doxorubicin (DOX) significantly limits its therapeutic efficacy in breast cancer (BC) patients. Saikosaponin D (SSD), a triterpene saponin derived from the traditional herb Radix Bupleuri, has shown promise as a chemotherapeutic sensitizer in preclinical studies due to its notable antitumor activity. However, the role and mechanism of SSD in DOX-resistant BC cells remain largely unexplored.This study aimed to investigate the chemosensitizing effect of SSD on DOX-resistant BC and the underlying molecular mechanisms both in vitro and in vivo.In vitro assays, including cell viability, clone formation, three-dimensional tumor spheroid growth, and apoptosis analysis, were conducted to evaluate the synergistic effect of SSD and DOX on resistant BC cells. Reactive oxygen species (ROS), GSH/GSSG, NADPH/NADP+, and NADH/NAD+ detections were employed to assess the impact of SSD on cellular redox homeostasis. Western blotting, cell cycle distribution assay, and DOX uptake assay were performed to further elucidate the possible antineoplastic mechanism of SSD. Finally, a subcutaneous MCF7/DOX cell xenografted model in nude mice was established to identify the in vivo anticarcinogenic effect of SSD combined with DOX.SSD significantly inhibited cell viability, proliferation, and clone formation, enhancing DOX's anticancer efficacy in vitro and in vivo. Mechanistically, SSD reduced STAT1, NQO1, and PGC-1α protein levels, leading to cellular redox imbalance, excessive ROS generation, and depletion of GSH, NADPH, and NADH. SSD induced DNA damage by disrupting redox homeostasis, resulting in G0/G1 phase cell cycle arrest. Additionally, SSD increased DOX accumulation in BC cells via inhibiting P-gp protein expression and efflux activity.We demonstrated for the first time that SSD enhances the sensitivity of chemoresistant BC cells to DOX by disrupting cellular redox homeostasis through inactivation of the STAT1/NQO1/PGC-1α signaling pathway. This study provides evidence for SSD as an adjuvant agent in drug-resistant BC treatment.Copyright © 2024 Elsevier GmbH. All rights reserved.