Table_9_Chidamide Reverses Fluzoparib Resistance in Triple-Negative Breast Cancer Cells.xlsx

Poly (ADP-ribose) polymerase inhibitor (PARPi) resistance is a new challenge for antitumor therapy. The purpose of this study was to investigate the reversal effects of chidamide on fluzoparib resistance, a PARPi, and its mechanism of action. A fluzoparib-resistant triple-negative breast cancer (TNBC) cell line was constructed, and the effects of chidamide and fluzoparib on drug-resistant cells were studied in vitro and in vivo. The effects of these drugs on cell proliferation, migration, invasiveness, the cell cycle, and apoptosis were detected using an MTT assay, wound-healing and transwell invasion assays, and flow cytometry. Bioinformatics was used to identify hub drug resistance genes and Western blots were used to assess the expression of PARP, RAD51, MRE11, cleaved Caspase9, and P-CDK1. Xenograft models were established to analyze the effects of these drugs on nude mice. In vivo results showed that chidamide combined with fluzoparib significantly inhibited the proliferation, migration, and invasiveness of drug-resistant cells and restored fluzoparib sensitivity to drug-resistant cells. The combination of chidamide and fluzoparib significantly inhibited the expression of the hub drug resistance genes RAD51 and MRE11, arrested the cell cycle at the G2/M phase, and induced cell apoptosis. The findings of this work show that chidamide combined with fluzoparib has good antineoplastic activity and reverses TNBC cell resistance to fluzoparil by reducing the expression levels of RAD51 and MRE11.

聚(ADP-核糖)聚合酶抑制剂（Poly (ADP-ribose) polymerase inhibitor, PARPi）耐药是抗肿瘤治疗面临的全新挑战。本研究旨在探讨西达本胺（chidamide）对PARPi类药物氟唑帕利（fluzoparib）耐药的逆转作用及其作用机制。本研究构建了氟唑帕利耐药的三阴性乳腺癌（triple-negative breast cancer, TNBC）细胞系，通过体内外实验探究西达本胺联合氟唑帕利对耐药细胞的作用效果。采用MTT检测法、划痕愈合实验、Transwell侵袭实验及流式细胞术，分别检测两种药物对细胞增殖、迁移、侵袭能力、细胞周期及细胞凋亡的影响；利用生物信息学筛选核心耐药基因，并通过蛋白质免疫印迹（Western blot）检测PARP、RAD51、MRE11、剪切型半胱氨酸天冬氨酸蛋白酶9（cleaved Caspase9）及磷酸化细胞周期蛋白依赖性激酶1（P-CDK1）的表达水平；构建异种移植模型，分析两种药物对裸鼠的治疗效果。体内外实验结果显示，西达本胺联合氟唑帕利可显著抑制耐药细胞的增殖、迁移与侵袭能力，并恢复耐药细胞对氟唑帕利的敏感性；该联合用药方案可显著下调核心耐药基因RAD51与MRE11的表达，将细胞周期阻滞于G2/M期，并诱导细胞凋亡。本研究结果表明，西达本胺联合氟唑帕利具有良好的抗肿瘤活性，可通过降低RAD51与MRE11的表达水平，逆转三阴性乳腺癌细胞对氟唑帕利的耐药性。