Fisetin induces autophagy in pancreatic cancer cells via endoplasmic reticulum stress- and mitochondrial stress-dependent pathways
Fisetin induces autophagy in pancreatic cancer cells via endoplasmic reticulum stress- and mitochondrial stress-dependent pathways
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非瑟酮通过内质网应激和线粒体应激依赖性途径诱导胰腺癌细胞自噬
DOI：
10.1038/s41419-019-1366-y
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发表时间：
2019-02-13
影响因子：
9
通讯作者：
Cao, Liping
中科院分区：
文献类型：
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作者：
Jia, Shengnan;Xu, Xiaodong;Cao, Liping
胰腺癌是最具侵袭性的肿瘤之一，患者的存活率很低。非瑟酮是一种天然的黄酮类化合物，最近有报道在各种癌症模型中具有抗肿瘤作用。自噬是一种保守的分解代谢过程，在应激反应中维持细胞内稳态，并与细胞凋亡一起决定细胞的命运。在此，我们研究了非赛汀对胰腺癌的作用。我们用实时细胞分析系统揭示了非瑟素抑制PANC-1细胞的增殖。此外，利用表达荧光素酶的小鼠移植胰腺癌模型，验证了非瑟素在胰腺癌中的体内抗肿瘤作用。我们发现，在Fisetin处理后，AMPK/mTOR信号通路被增强；然而，加入AMPK抑制剂化合物C并不能减少自噬。因此，我们假设存在另一条自噬调节通路。RNA-seq分析表明，由内质网应激激活的未折叠蛋白反应通路被丰富。我们还发现，在经非瑟素处理的PANC-1细胞中，应激诱导的转录因子p8增加，并且非瑟素诱导的自噬通过沉默p8而被阻断。我们发现p8依赖的自噬是AMPK不依赖的，p8通过P53/PKC-α介导的信号调节ATF6、ATF4和PERK来应对内质网应激。此外，吞噬丝裂原与Parkin和PINK1对线粒体应激的反应有关。有趣的是，在Fisetin和化合物C处理的细胞中，ATF4和ATF6增加。此外，用化合物C抑制AMPK/mTOR通路可能上调依赖p8的自噬。因此，AMPK/mTOR和p8依赖的通路之间可能存在串扰。
Pancreatic cancer is one of the most aggressive tumors and patients have poor survival rates. Fisetin, a natural flavonoid, was recently reported to have antitumor effects in various cancer models. Autophagy is a conserved catabolic process that maintains cellular homoeostasis in response to stress, and together with apoptosis, determines cell fate. Herein, we examined the effect of fisetin on pancreatic cancer. We reveal that fisetin inhibits PANC-1 cell proliferation using a real-time cell analysis system. Moreover, the in vivo antitumor effect of fisetin was verified in pancreatic cancer using a luciferase-expressing murine xenograft pancreatic cancer model. We found that the AMPK/mTOR signaling pathway was enhanced after fisetin treatment; however, autophagy was not diminished by adding the AMPK inhibitor compound C. Thus, we hypothesized that an another autophagy regulating pathway existed. RNA-seq analysis revealed that the unfolded protein response pathway, which is activated by ER stress, was enriched. We also found that the stress-induced transcription factor p8 was increased in fisetin-treated PANC-1 cells, and that fisetin-induced autophagy was blocked by silencing p8. We revealed that p8-dependent autophagy was AMPK-independent, and that p8 regulated ATF6, ATF4, and PERK in response to ER stress via p53/PKC-α-mediated signaling. Furthermore, mitophagy was associated with Parkin and PINK1 in response to mitochondrial stress. Interestingly, ATF4 and ATF6 were increased in cells treated with fisetin and compound C. Moreover, inhibiting the AMPK/mTOR pathway with compound C may upregulate p8-dependent autophagy. Thus, there may be crosstalk between the AMPK/mTOR and p8-dependent pathways.