Zhang Weipeng, Cai Jiangxia, Chen Siying, Zheng Xiaowei, Hu Sasa, Dong Weihua, Lu Jun, Xing Jianfeng, Dong Yalin
Department of Pharmacy, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Department of Pharmacy, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Mol Med Rep. 2015 Jul;12(1):1506-14. doi: 10.3892/mmr.2015.3468. Epub 2015 Mar 11.
Breast cancer is one of the most prevalent types of malignant tumor. Paclitaxel is widely used in the treatment of breast cancer; however, the major problem contributing to the failure of chemotherapy in breast cancer is the development of drug resistance. Therefore, it is necessary to identify novel therapeutic targets and reversal agents for breast cancer. In the present study, the protein expression levels of SET, protein phosphatase 2A (PP2A) and phosphatidylinositol 3-kinase (PI3K)/Akt pathway were determined in MCF-7/PTX human breast carcinoma paclitaxel-resistant cells using western blot analysis. Small interference RNAs (siRNAs) were used to knock down the gene expression of SET in MCF-7/PTX cells and the cell viability was assessed following treatment with paclitaxel, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assays and flow cytometry. In addition, western blot analysis was used to determined PI3K/Akt pathway activity following SET knockdown. Furthermore, the reversal effects of paeonol on paclitaxel, and its underlying mechanisms of action, were investigated using western blot analysis and reverse transcription-quantitative polymerase chain reaction. The results demonstrated that increased levels of SET and PI3K/Akt pathway proteins were present in the MCF-7/PTX cells, compared with normal MCF-7 cells. Knockdown of SET significantly sensitized MCF-7/PTX cells to paclitaxel and induced cell apoptosis. In addition, the expression levels of the adenosine triphosphate binding cassette (ABC) transporter proteins were significantly reduced in the MCF-7/PTX cells compared with the normal MCF-7 cells. SET-induced paclitaxel resistance was found to be associated with the activation of the PI3K/Akt pathway. Paeonol significantly reduced the mRNA and protein expression levels of SET in the MCF-7/PTX cells. Furthermore, paeonol significantly sensitized the MCF-7/PTX to paclitaxel via regulation of ABC transporters, B cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein. In addition, paeonol inhibited SET-mediated paclitaxel resistance by attenuating PI3K/Akt pathway activity in the MCF-7/PTX cells. In conclusion, the results of the present study demonstrated that SET was associated with paclitaxel resistance in MCF-7/PTX cells, and that paeonol reversed paclitaxel resistance in MCF-7/PTX cells by downregulating the activity of the SET/PP2A/Akt pathway.
乳腺癌是最常见的恶性肿瘤类型之一。紫杉醇广泛用于乳腺癌的治疗；然而，导致乳腺癌化疗失败的主要问题是耐药性的产生。因此，有必要确定乳腺癌的新型治疗靶点和逆转剂。在本研究中，使用蛋白质印迹分析测定了MCF-7/PTX人乳腺癌紫杉醇耐药细胞中SET、蛋白磷酸酶2A（PP2A）和磷脂酰肌醇3-激酶（PI3K）/Akt信号通路的蛋白表达水平。使用小干扰RNA（siRNA）敲低MCF-7/PTX细胞中SET的基因表达，并在紫杉醇处理后，使用3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐法和流式细胞术评估细胞活力。此外，使用蛋白质印迹分析测定SET敲低后PI3K/Akt信号通路的活性。此外，使用蛋白质印迹分析和逆转录-定量聚合酶链反应研究了丹皮酚对紫杉醇的逆转作用及其潜在作用机制。结果表明，与正常MCF-7细胞相比，MCF-7/PTX细胞中SET和PI3K/Akt信号通路蛋白水平升高。敲低SET可显著使MCF-7/PTX细胞对紫杉醇敏感并诱导细胞凋亡。此外，与正常MCF-7细胞相比，MCF-7/PTX细胞中三磷酸腺苷结合盒（ABC）转运蛋白的表达水平显著降低。发现SET诱导的紫杉醇耐药与PI3K/Akt信号通路的激活有关。丹皮酚显著降低了MCF-7/PTX细胞中SET的mRNA和蛋白表达水平。此外，丹皮酚通过调节ABC转运蛋白、B细胞淋巴瘤-2（Bcl-2）和Bcl-2相关X蛋白，使MCF-7/PTX细胞对紫杉醇显著敏感。此外，丹皮酚通过减弱MCF-7/PTX细胞中PI3K/Akt信号通路的活性，抑制SET介导的紫杉醇耐药。总之，本研究结果表明，SET与MCF-7/PTX细胞中的紫杉醇耐药有关，丹皮酚通过下调SET/PP2A/Akt信号通路的活性逆转MCF-7/PTX细胞中的紫杉醇耐药。
