ATF4/PHGDH介导内质网应激对镉诱导的自噬和糖酵解的影响
ATF4/PHGDH mediates the effects of ER stress on cadmium-induced autophagy and glycolysis
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影响因子:4.6
分区:医学3区 / 药学2区 毒理学2区
发表日期:2024 Dec
作者:
Yanqiu Yang, Shengnan Li, Yuanxi Yang, Qiujuan Li, Yong Liu, Jun Cao
DOI:
10.1016/j.tox.2024.153976
摘要
镉（Cd）被归类为I类致癌物，但其致癌机制仍未完全阐明。我们的前期研究表明，2 μM CdCl2可诱导A549细胞发生自噬。在本研究中，我们探讨了ATF4/PHGDH在Cd诱导的自噬和糖酵解增强中的作用。首先，通过皮下注射A549细胞（联合或未联合Cd和siPHGDH）建立异种移植肿瘤模型，结果显示PHGDH在体内促进镉诱导的自噬。暴露于Cd的A549细胞分别接受siPHGDH和0.4 mM甘氨酸（Gly）处理。Western印迹和吖啶橙染色显示PHGDH促进镉诱导的自噬。使用ER应激抑制剂4-PBA（5 mM）或ER应激诱导剂Tm（0.1 μg/ml）可抑制PHGDH的表达。联合siPHGDH处理后，验证了PHGDH介导ER应激引发的自噬。此外，转染siATF4抑制了Tm诱导的PHGDH表达。ChIP-qPCR实验揭示了ATF4对PHGDH的转录调控机制。同时，通过划痕实验探讨了ER应激/PHGDH/自噬在镉促进细胞迁移中的作用。最后，阐明了ER应激/PHGDH/自噬在镉诱导的糖酵解中的作用。总结来说，ATF4对PHGDH的转录调控在镉引发的ER应激相关自噬中起到关键作用，ER应激/PHGDH/自噬轴通过增强糖酵解促进镉引起的细胞迁移。
Abstract
Cadmium (Cd) has been classified as a Class I carcinogen, but the mechanism of its carcinogenicity is still unknown. Our previous study demonstrated that 2 μM CdCl2 induced autophagy in A549 cells. In this study, we investigated the role of ATF4/PHGDH in Cd-induced autophagy and increased glycolysis. First, BALB/c mice were subcutaneously injected with A549 cells co-treated with or without Cd and siPHGDH to establish a xenograft tumor model, which demonstrated that PHGDH promotes Cd-induced autophagy in vivo. Cd-exposed A549 cells were treated with siPHGDH and 0.4 mM glycine (Gly), respectively. Western blot analysis and Acridine orange staining revealed that PHGDH promotes Cd-induced autophagy. Using 4-PBA (5 mM), the inhibitor of ER stress, or Tm (0.1 μg/ml), the inducer of ER stress, inhibited Cd-induced PHGDH expression. After co-treatment with siPHGDH, PHGDH was determined to mediate ER stress-induced autophagy. Furthermore, transfection with siATF4 inhibited Tm-induced PHGDH expression. ChIP-qPCR experiments demonstrated the transcription regulatory mechanism of ATF4 on PHGDH. Meanwhile, the role of ER stress/PHGDH/autophagy in Cd-promoted cell migration was explored by scratch assay. Finally, the role of ER stress/PHGDH/autophagy in Cd-induced glycolysis was unveiled. In summary, the transcriptional regulation of PHGDH by ATF4 plays a crucial role in Cd-induced autophagy triggered by ER stress. The axis of ER stress/PHGDH/autophagy is important in Cd-induced cell migration by enhancing glycolysis.