Autophagy Stimulates Apoptosis in HER2-Overexpressing Breast Cancers Treated by Lapatinib
Autophagy Stimulates Apoptosis in HER2-Overexpressing Breast Cancers Treated by Lapatinib
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自噬刺激拉帕替尼治疗的 HER2 过表达乳腺癌细胞凋亡
DOI：
10.1002/jcb.24611
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发表时间：
2013-12-01
影响因子：
4
通讯作者：
Zhang, Jian
中科院分区：
文献类型：
--
作者：
Zhu, Xingmei;Wu, Lin;Zhang, Jian
HER 2过表达乳腺癌通常表现出HER 2/AKT/mTOR信号通路的过度活化。拉帕替尼是一种口服双重酪氨酸激酶抑制剂（TKI），靶向EGFR和HER 2，以抑制乳腺癌细胞的增殖。然而，拉帕替尼是否以及如何在乳腺癌细胞中诱导自噬尚不清楚，这是药物治疗的一种重要细胞反应。在这项研究中，我们研究了拉帕替尼处理过的HER 2过表达乳腺癌细胞BT474和AU565中的凋亡和自噬，并进一步研究了它们之间的关系。拉帕替尼抑制HER 2阳性细胞的增殖和DNA合成速率，如通过MTT、集落形成和EDU测定所观察到的。拉帕替尼不仅诱导细胞凋亡，伴随着裂解的Caspase-3和裂解的PARP的表达增加，而且还诱导体外自噬，如通过电子显微镜（EM）、吖啶橙子（AO）染色和LC 3-II表达所证实的。同时，拉帕替尼抑制HER 2、AKT、mTOR和p70 S6 K的磷酸化，而AMPK的磷酸化被激活。3-甲基腺嘌呤（3-Methyladenine，3-MA）作为细胞自噬的特异性抑制剂，能抑制细胞的生长抑制率和凋亡率，促进细胞集落形成和DNA合成能力。此外，3-MA应用可以上调Caspase-3和PARP的表达，与拉帕替尼单独治疗相比。加入3-MA可减弱拉帕替尼对HER 2/AKT/mTOR通路的抑制作用和对AMPK的激活作用。因此，拉帕替尼在BT474和AU565细胞中同时诱导凋亡和自噬，在这些情况下，自噬促进凋亡。J.细胞。114：2643-2653，2013. (c)2013 Wiley Periodicals，Inc.
HER2-overexpressing breast cancers often show hyperactivation of the HER2/AKT/mTOR signaling pathway. Lapatinib is an oral dual tyrosine kinase inhibitor (TKI) that targets both EGFR and HER2 to inhibit the proliferation of breast cancer cells. However, it is obscure whether and how lapatinib could induce autophagy in breast cancer cells, an important cell response with drug treatment. In this study, we investigated the apoptosis and the autophagy in the HER2-overexpressing breast cancer cells BT474 and AU565 treated with lapatinib, and further examined their relationship. Lapatinib inhibited the proliferation and the rate of DNA synthesis in HER2-positive cells, as observed by MTT, colony formation and EDU assays. Lapatinib not only induced apoptosis accompanied by an increased expression of cleaved Caspase-3 and cleaved PARP, but it also induced autophagy in vitro, as confirmed by electron microscopy (EM), acridine orange (AO) staining and LC3-II expression. Meanwhile, lapatinib inhibited the phosphorylation of HER2, AKT, mTOR, and p70S6K, whereas that of AMPK was activated. When the cells were pre-incubated with 3-Methyladenine (3-MA), the specific autophagy inhibitor, the growth inhibitory ratio and apoptosis rate were frustrated, whereas colony formation and DNA synthesis ability were encouraged. In addition, 3-MA application could up-regulate Caspase-3 and PARP expression, compared with the treatment with lapatinib alone. The addition of 3-MA could attenuate the inhibitory role on HER2/AKT/mTOR pathway and the active role on AMPK that was raised by lapatinib. Therefore, lapatinib simultaneously induced both apoptosis and autophagy in the BT474 and AU565 cells, and in these settings, autophagy facilitates apoptosis. J. Cell. Biochem. 114: 2643-2653, 2013. (c) 2013 Wiley Periodicals, Inc.