Department of Physiology and Hypoxic Biomedicine, Institute of Special Environmental Medicine and Co-innovation Center of Neuroregeneration, Nantong University, 9 Seyuan Road, Chongchuan District, Nantong, 226019, Jiangsu, China.
Department of Emergency, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, China.
Breast Cancer Res Treat. 2019 Jul;176(2):291-301. doi: 10.1007/s10549-019-05239-3. Epub 2019 Apr 20.
Phosphorylated AKT is highly expressed or overexpressed in chemoresistant tumor samples. However, the precise molecular mechanism involved in AKT phosphorylation-related chemoresistance in breast cancer is still elusive. The present research was designed to estimate the effect of AKT phosphorylation on cell viability and chemoresistance in breast cancer.
We utilized MCF-7 and MDA-MB468 human breast cancer cell lines and developed multidrug-resistant MCF-7/MDR and cisplatin-resistant MDA-MB-468 cells. Immunofluorescence analysis and Western blotting were employed to test the level of glycogen synthase kinase 3 beta (GSK3β), phosphorylated phosphatase and tension homologue (p-PTEN) and phosphorylated AKT (p-AKT) in MCF-7/MDR and MDA-MB468 cells. Xenograft assays in nude mice were performed with MCF-7/MDR cells to verify chemoresistance and the signaling pathway upstream of phosphatidylinositide 3-kinase (PI3K)/AKT.
An increase in GSK3β, p-PTEN and p-AKT expression was strongly induced in MCF-7/MDR and cisplatin-resistant MDA-MB-468 cells, and augmented GSK3β phosphorylation and PTEN inactivation enhanced AKT signaling. The elevation in GSK3β, p-PTEN and p-AKT was associated with cell viability based on a CCK-8 assay. The results of in vivo and in vitro assays indicated that GSK3β knockdown with lentiviral shRNA (shRNA-GSK3β) promoted apoptosis and suppressed the migration of cisplatin-resistant MCF-7/MDR cells, while these effects were reversed by activating p-AKT with the PTEN inhibitor bpV(pic).
AKT phosphorylation mediated by GSK3β and PTEN were correlated with cell viability, migration and apoptosis, which may promote chemoresistance in breast cancer. Furthermore, GSK3β can regulate cell viability through the PTEN/PI3K/AKT signaling pathway and induce chemoresistance, serving as a valuable molecular strategy for breast cancer therapy.
磷酸化 AKT 在耐药肿瘤样本中高度表达或过表达。然而，AKT 磷酸化相关化疗耐药的精确分子机制仍不清楚。本研究旨在评估 AKT 磷酸化对乳腺癌细胞活力和化疗耐药性的影响。
我们利用 MCF-7 和 MDA-MB468 人乳腺癌细胞系，并建立了多药耐药 MCF-7/MDR 和顺铂耐药 MDA-MB-468 细胞。免疫荧光分析和 Western blot 用于检测 MCF-7/MDR 和 MDA-MB468 细胞中糖原合成酶激酶 3β（GSK3β）、磷酸化磷酸酶和张力同源物（p-PTEN）和磷酸化 AKT（p-AKT）的水平。使用 MCF-7/MDR 细胞进行裸鼠异种移植实验，以验证磷脂酰肌醇 3-激酶（PI3K）/AKT 信号通路的上游的化疗耐药性。
在 MCF-7/MDR 和顺铂耐药 MDA-MB-468 细胞中，GSK3β、p-PTEN 和 p-AKT 的表达水平显著增加，增强的 GSK3β 磷酸化和 PTEN 失活增强了 AKT 信号。CCK-8 测定结果表明，GSK3β、p-PTEN 和 p-AKT 的升高与细胞活力有关。体内和体外实验结果表明，用慢病毒 shRNA（shRNA-GSK3β）敲低 GSK3β 促进了顺铂耐药 MCF-7/MDR 细胞的凋亡并抑制了其迁移，而用 PTEN 抑制剂 bpV(pic)激活 p-AKT 则逆转了这些作用。
由 GSK3β 和 PTEN 介导的 AKT 磷酸化与细胞活力、迁移和凋亡相关，可能促进乳腺癌的化疗耐药性。此外，GSK3β 可以通过 PTEN/PI3K/AKT 信号通路调节细胞活力，并诱导化疗耐药性，因此可作为乳腺癌治疗的有价值的分子策略。
