镉（Cd）已被列为I类致癌物，但其致癌机制尚不清楚。我们之前的研究表明，2μM CdCl2 可以诱导 A549 细胞发生自噬。在这项研究中，我们研究了 ATF4/PHGDH 在 Cd 诱导的自噬和糖酵解增加中的作用。首先，BALB/c小鼠皮下注射Cd和siPHGDH共处理或不联合处理的A549细胞，建立异种移植肿瘤模型，证明PHGDH在体内促进Cd诱导的自噬。分别用 siPHGDH 和 0.4mM 甘氨酸 (Gly) 处理暴露于 Cd 的 A549 细胞。蛋白质印迹分析和吖啶橙染色表明 PHGDH 促进 Cd 诱导的自噬。使用 4-PBA (5mM)（ER 应激抑制剂）或 Tm（0.1μg/ml）（ER 应激诱导剂）抑制 Cd 诱导的 PHGDH 表达。与 siPHGDH 共同治疗后，PHGDH 被确定可介导 ER 应激诱导的自噬。此外，siATF4 转染抑制了 Tm 诱导的 PHGDH 表达。 ChIP-qPCR 实验证明了 ATF4 对 PHGDH 的转录调控机制。同时，通过划痕实验探讨了内质网应激/PHGDH/自噬在Cd促进细胞迁移中的作用。最后，揭示了 ER 应激/PHGDH/自噬在 Cd 诱导的糖酵解中的作用。总之，ATF4 对 PHGDH 的转录调控在 ER 应激引发的 Cd 诱导自噬中发挥着至关重要的作用。 ER 应激/PHGDH/自噬轴在镉诱导的细胞迁移中通过增强糖酵解发挥重要作用。版权所有 © 2024 Elsevier B.V. 保留所有权利。

Cadmium (Cd) has been classified as a Class I carcinogen, but the mechanism of its carcinogenicity is still unknown. Our previous study demonstrated that 2μM 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 0.4mM glycine (Gly), respectively. Western blot analysis and Acridine orange staining revealed that PHGDH promotes Cd-induced autophagy. Using 4-PBA (5mM), the inhibitor of ER stress, or Tm (0.1μg/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.Copyright © 2024 Elsevier B.V. All rights reserved.