Radiation induces autophagic cell death via the p53/DRAM signaling pathway in breast cancer cells
Radiation induces autophagic cell death via the p53/DRAM signaling pathway in breast cancer cells
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DOI：
10.3892/or.2016.4752
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发表时间：
2016-06-01
期刊：
影响因子：
4.2
通讯作者：
Liu, Xiaodong
中科院分区：
文献类型：
--
作者：
Cui, Li;Song, Zhiheng;Liu, Xiaodong
已知自噬在乳腺癌细胞对放射治疗的反应中起作用。然而，介导自噬过程并有助于辐射诱导的细胞死亡和细胞存活的机制仍有待充分表征。因此，在本研究中，自噬在乳腺癌细胞辐射诱导的细胞毒性中的功能作用进行了研究。MCF-7细胞暴露于不同剂量的辐射后，观察到单丹酰尸胺（MDC）染色增加和LC 3阳性斑点的沉积增加。自噬相关蛋白Beclin 1和LC 3-II的表达也被发现上调。放射诱导的自噬性细胞死亡被部分废除后，管理的3-甲基腺嘌呤（3-MA）和Atg 5和Beclin I的敲低实验。在基因微阵列分析进行照射后，一些差异表达的基因被确定。特别地，检测到自噬相关基因DRAM和TIGAR的mRNA和蛋白质水平的上调。然而，通过3-MA抑制自噬减少了辐射诱导的LC 3-II和DRAM的上调。相反，p53的沉默下调辐射后LC 3-II和DRAM的表达。DRAM的沉默逆转了辐射后LC 3-II和DRAM的上调，部分阻断了辐射诱导的细胞死亡，并且检测到p53表达没有显著变化。基于这些结果，p53/DRAM信号通路似乎有助于MCF-7乳腺癌细胞中辐射诱导的自噬细胞死亡。
Autophagy is known to play a role in the response of breast cancer cells to radiation therapy. However, the mechanisms that mediate the process of autophagy and contribute to radiation-induced cell death and cell survival remain to be fully characterized. Therefore, in this study, the functional role of autophagy in radiation-induced cytotoxicity in breast cancer cells was investigated. After MCF-7 cells were exposed to various doses of radiation, increased monodansylcadaverine (MDC) staining and a greater deposition of LC3-positive puncta were observed. Expression of the autophagy-related proteins, Beclin 1 and LC3-II, were also found to be upregulated. Radiation-induced autophagic cell death was partially abrogated following the administration of 3-methyladenine (3-MA) and in knockdown experiments of Atg5 and Beclin I. In the gene microarray analysis performed after irradiation, a number of differentially expressed genes were identified. In particular, upregulation of both the mRNA and protein levels of the autophagy-related genes, DRAM and TIGAR, were detected. However, inhibition of autophagy by 3-MA reduced the radiation-induced upregulation of LC3-II and DRAM. Conversely, silencing of p53 downregulated the expression of LC3-II and DRAM following radiation. Silencing of DRAM reversed the upregulation of LC3-II and DRAM following radiation, partially blocked radiation-induced cell death, and no significant change in p53 expression was detected. Based on these results, the p53/DRAM signaling pathway appears to contribute to radiation-induced autophagic cell death in MCF-7 breast cancer cells.