Department of Oncology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong 266071, P.R. China.
Department of General Surgery, The First Affiliated Hospital, Dalian Medical University, Dalian 116011, P.R. China.
Int J Med Sci. 2021 Jan 1;18(2):325-334. doi: 10.7150/ijms.54301. eCollection 2021.
The evolution of adriamycin (ADR) resistance in the treatment of breast cancer often leads to a poor prognosis in patients. Ubiquitin-specific peptidase 37 (USP37) has been recently identified as a modulator in regulating the stemness of breast cancer cells, but its underlying mechanism remains unclear. In this study, we investigated whether USP37 knockdown could hamper the chemical resistance of MCF-7 and MCF-7/ADR cells to adriamycin and elucidated the potential mechanism. Immunohistochemistry, western blotting, and RT-qPCR assays were performed to detect the USP37 expression in MCF-7 and MCF-7/ADR cells. The efficiency of USP37 knockdown in breast cancer cells was confirmed by western blotting and RT-qPCR assays. We also performed CCK-8 assay, flow cytometry, western blotting, and TUNEL assays to evaluate cell viability and apoptosis in breast cancer cells. study was performed to detect the tumorigenicity of MCF-7/ADR cells transfected with shScramble or shUSP37#1 under adriamycin treatment. Bioinformatic analysis indicated that USP37 overexpression was positively correlated with adriamycin resistance. The expression levels of USP37 in both MCF-7 and MCF-7/ADR cells increased significantly with the exposure to adriamycin in a dose-dependent manner. It was verified by the observation that USP37 downregulation elevated the inhibitory effects of adriamycin on breast cancer cells, suppressed cell proliferation caused by cell cycle arrest in G1/S transition, as well as induced apoptosis. Furthermore, study showed that knockdown of USP37 expression also decreased tumorigenicity of MCF-7/ADR cells in mice. TUNEL assay and observation of cell morphology magnified USP37 knockdown synergized with Adriamycin could elevate the apoptosis of MCF-7 and MCF-7/ADR cells. Western blotting assay illustrated that the combination of USP37 knockdown with adriamycin treatment significantly upregulated the expression levels of cleaved caspase 3 and Bax, whereas the expression level of Bcl-2 was inhibited. Knockdown of USP37 gene expression can reverse the resistance of breast cancer cells to adriamycin, and down-regulating USP37 might be a valuable strategy against ADR resistance in breast cancer therapy.
阿霉素（ADR）耐药性的演变在乳腺癌的治疗中常常导致患者预后不良。泛素特异性肽酶 37（USP37）最近被鉴定为调节乳腺癌细胞干性的调节剂，但其潜在机制尚不清楚。在这项研究中，我们研究了 USP37 敲低是否会阻碍 MCF-7 和 MCF-7/ADR 细胞对阿霉素的化学耐药性，并阐明了潜在的机制。通过免疫组织化学、Western blot 和 RT-qPCR 检测 MCF-7 和 MCF-7/ADR 细胞中 USP37 的表达。Western blot 和 RT-qPCR 检测证实了 USP37 在乳腺癌细胞中的敲低效率。我们还进行了 CCK-8 测定、流式细胞术、Western blot 和 TUNEL 测定，以评估乳腺癌细胞的活力和凋亡。进行了研究，以检测在阿霉素处理下转染 shScramble 或 shUSP37#1 的 MCF-7/ADR 细胞的致瘤性。生物信息学分析表明，USP37 过表达与阿霉素耐药性呈正相关。随着阿霉素剂量依赖性地暴露，MCF-7 和 MCF-7/ADR 细胞中的 USP37 表达水平显著增加。USP37 下调增强了阿霉素对乳腺癌细胞的抑制作用，抑制了细胞周期停滞在 G1/S 期引起的细胞增殖，并诱导了细胞凋亡。此外，研究表明，USP37 表达的敲低也降低了 MCF-7/ADR 细胞在小鼠中的致瘤性。TUNEL 测定和细胞形态观察放大了 USP37 敲低与阿霉素联合使用可以提高 MCF-7 和 MCF-7/ADR 细胞的凋亡。Western blot 测定表明，USP37 敲低与阿霉素处理联合显著上调了 cleaved caspase 3 和 Bax 的表达水平，而 Bcl-2 的表达水平则受到抑制。敲低 USP37 基因表达可以逆转乳腺癌细胞对阿霉素的耐药性，下调 USP37 可能是乳腺癌治疗中对抗 ADR 耐药性的一种有价值的策略。
