Department of Oncology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, China.
Department of Thyroid Breast Vascular Surgery, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, China.
Chem Biol Drug Des. 2024 Jun;103(6):e14559. doi: 10.1111/cbdd.14559.
This study aimed to investigate whether silencing Protein L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) expression can enhance the sensitivity of breast cancer cells to paclitaxel and its possible mechanism. Tumor tissues and adjacent histologically normal tissues were collected from patients with breast cancer admitted to our hospital. Human normal breast epithelial cells MCF10A, human breast cancer cells MCF-7, and paclitaxel-resistant breast cancer cells MCF-7/PR were purchased. MCF-7/PR cells were further grouped into negative control (NC) group, si-PCMT1 group (transfected with si-PCMT1), 740Y-P group (treated with 740Y-P, an activator of phosphatidylinositol 3-kinase (PI3K)/ v-Akt Murine Thymoma Viral Oncogene (AKT) signaling pathway), and si-PCMT1 + 740Y-P group (transfected with si-PCMT1 and then treated with 740Y-P). The expression level of PCMT1 in tissues and cells was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot analysis was used to detect the protein expression level of PCMT1 in tissues and cells as well as the protein level of p-PI3K, PI3K, p-Akt, Akt, and Stathmin1 (STMN1) in cells. 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) and colony formation assays were used to determine cell viability, scratch assay was used to assess the migration ability of cells, and Transwell assay was used to assess the invasion ability of cells. The expression of PCMT1 was remarkably up-regulated in breast cancer tissues and MCF-7/PR cells. Silencing PCMT1 expression significantly inhibited the proliferation, migration, and invasion of MCF-7/PR cells, and alleviated the resistance of cancer cells to paclitaxel. Additionally, silencing PCMT1 expression also inhibited the activation of PI3K/Akt/STMN1 pathway in MCF-7/PR cells, while activating PI3K/Akt/STMN1 pathway significantly reversed the effect of silencing PCMT1 expression on MCF-7/PR cells. PCMT1 is highly expressed in breast cancer tissues and MCF-7/PR cells, and silencing PCMT1 expression can not only inhibit the development of breast cancer but also enhance paclitaxel sensitivity. Its mechanism of action may be achieved by inhibiting PI3K/Akt/STMN1 signaling.
本研究旨在探讨沉默蛋白 L-异天冬氨酸（D-天冬氨酸）O-甲基转移酶（PCMT1）表达能否增强乳腺癌细胞对紫杉醇的敏感性及其可能的机制。收集我院收治的乳腺癌患者的肿瘤组织和相邻组织学正常组织。购买人正常乳腺上皮细胞 MCF10A、人乳腺癌细胞 MCF-7 和紫杉醇耐药乳腺癌细胞 MCF-7/PR。将 MCF-7/PR 细胞进一步分为阴性对照组（NC 组）、si-PCMT1 组（转染 si-PCMT1）、740Y-P 组（用激活磷脂酰肌醇 3-激酶（PI3K）/v-Akt 鼠胸腺瘤病毒癌基因（AKT）信号通路的 740Y-P 处理）和 si-PCMT1+740Y-P 组（转染 si-PCMT1 后用 740Y-P 处理）。采用实时定量聚合酶链反应（qRT-PCR）检测组织和细胞中 PCMT1 的表达水平。Western blot 分析检测组织和细胞中 PCMT1 的蛋白表达水平以及细胞中 p-PI3K、PI3K、p-Akt、Akt 和 Stathmin1（STMN1）的蛋白水平。3-(4,5)-二甲基噻唑(-z-y1)-3,5-二苯基四唑溴盐（MTT）和集落形成实验用于测定细胞活力，划痕实验用于评估细胞迁移能力，Transwell 实验用于评估细胞侵袭能力。PCMT1 在乳腺癌组织和 MCF-7/PR 细胞中表达明显上调。沉默 PCMT1 表达显著抑制 MCF-7/PR 细胞的增殖、迁移和侵袭，并减轻癌细胞对紫杉醇的耐药性。此外，沉默 PCMT1 表达还抑制 MCF-7/PR 细胞中 PI3K/Akt/STMN1 通路的激活，而激活 PI3K/Akt/STMN1 通路则显著逆转了沉默 PCMT1 表达对 MCF-7/PR 细胞的影响。PCMT1 在乳腺癌组织和 MCF-7/PR 细胞中高表达，沉默 PCMT1 表达不仅能抑制乳腺癌的发展，而且能增强紫杉醇的敏感性。其作用机制可能是通过抑制 PI3K/Akt/STMN1 信号通路实现的。
