TGF-β1-mediated repression of SLC7A11 drives vulnerability to GPX4 inhibition in hepatocellular carcinoma cells
TGF-β1-mediated repression of SLC7A11 drives vulnerability to GPX4 inhibition in hepatocellular carcinoma cells
复制标题
DOI：
10.1038/s41419-020-2618-6
复制
发表时间：
2020-05-29
影响因子：
9
通讯作者：
Lee, Seung Jin
中科院分区：
文献类型：
--
作者：
Kim, Do Hyung;Kim, Won Dong;Lee, Seung Jin
系统x（c）（-）有助于谷胱甘肽（GSH）的合成，并通过输入胱氨酸并将其与谷氨酸交换来保护细胞免受铁凋亡。转化生长因子β 1（TGF-β 1）诱导氧化还原失衡;然而，其在系统x（c）（-）调节中的作用仍然知之甚少。目前的研究首次表明，TGF-β 1抑制xCT的蛋白质和mRNA水平，系统x（c）（-）的催化亚基，在PLC/PRF/5，Huh 7，Huh 6和HepG 2细胞与早期TGF-β 1基因签名，但不与SNU387，SNU449，SNU475和SK-Hep1细胞与晚期TGF-β 1基因签名。TGF-β 1处理24小时以剂量依赖性方式降低xCT表达，但TGF-β 1诱导的抑制通过用TGF-β 1受体抑制剂预处理而减弱。TGF-β 1介导的xCT抑制被Smad3抑制，而不是Smad2或Smad4，敲低，而Smad3过表达增强。TGF-β 1降低对照细胞中的GSH水平，但不降低xCT过表达细胞中的GSH水平。此外，TGF-β 1增加了PLC/PRF/5细胞中的活性氧（ROS）水平，并增强了Huh 7细胞中叔丁基过氧化氢诱导的ROS水平;这些变化被xCT过表达逆转。TGF-β 1处理后2天和8天，PLC/PRF/5和Huh 7细胞最终诱导了ferostatin-1和去铁胺依赖性脂质过氧化，但SNU475和SK-Hep1细胞中未诱导。在PLC/PRF/5和Huh 7细胞中，TGF-β 1预处理2天增强了由GSH过氧化物酶4（GPX4）抑制剂RSL3诱导的细胞活力的降低。总之，TGF-β 1通过Smad3激活抑制xCT表达，并增强具有早期TGF-β 1特征的肝细胞癌细胞中的脂质过氧化，这将受益于GPX4的靶向。
System x(c)(-) contributes to glutathione (GSH) synthesis and protects cells against ferroptosis by importing cystine and exchanging it with glutamate. Transforming growth factor beta 1 (TGF-beta 1) induces redox imbalance; however, its role in system x(c)(-) regulation remains poorly understood. The present study was the first to show that TGF-beta 1 repressed the protein and mRNA levels of xCT, a catalytic subunit of system x(c)(-), in PLC/PRF/5, Huh7, Huh6, and HepG2 cells with an early TGF-beta 1 gene signature but not in SNU387, SNU449, SNU475, and SK-Hep1 cells with a late TGF-beta 1 gene signature. TGF-beta 1 treatment for 24 h reduced xCT expression in a dose-dependent manner but this TGF-beta 1-induced repression was blunted by pretreatment with a TGF-beta 1 receptor inhibitor. TGF-beta 1-mediated xCT repression was prevented by Smad3, but not Smad2 or Smad4, knockdown, whereas it was enhanced by Smad3 overexpression. TGF-beta 1 decreased GSH levels in control cells but not xCT-overexpressed cells. Furthermore, TGF-beta 1 increased reactive oxygen species (ROS) levels in PLC/PRF/5 cells and enhanced tert-butyl hydroperoxide-induced ROS levels in Huh7 cells; these changes were reversed by xCT overexpression. TGF-beta 1 treatment ultimately induced the ferrostatin-1- and deferoxamine-dependent lipid peroxidation after 2 days and 8 days in PLC/PRF/5 and Huh7 cells but not in SNU475 and SK-Hep1 cells. Pre-treatment of TGF-beta 1 for 2 days enhanced the reduction of cell viability induced by RSL3, a GSH peroxidase 4 (GPX4) inhibitor, in PLC/PRF/5 and Huh7 cells. In conclusion, TGF-beta 1 represses xCT expression via Smad3 activation and enhances lipid peroxidation in hepatocellular carcinoma cells with an early TGF-beta 1 signature, which would benefit from the targeting of GPX4.