TET1-mediated DNA hydroxymethylation controlling ferroptosis resistance in cancer [RNA-seq]

Ferroptosis, a non-apoptotic programmed cell death marked by iron-dependent lipid peroxidation, is closely associated with cancer. Despite of intensive investigation about the molecular pathways underlying ferroptosis, the mechanism that determines the disparity of cancer cell vulnerability to ferroptosis remains unclear. Here we show that the expression level of TET1, the founding member of the ten-eleven translocation (TET) family of enzymes that mediate DNA 5-hydroxymethylation, determines the susceptibility of cancer cells to ferroptosis. In ferroptosis resistant cells, the expression level of TET1 was remarkably higher than that of the sensitive cells. Cell response to ferroptosis could be affected by interfering TET1 expression. TET1 promoted DNA 5hmC modification at its target gene GCLM, activated both the canonical glutathione (GSH) synthesis, and the non-cannonical ?-glutamyl-peptide accumulation, and thus, protected cancer cells against ferroptosis. Our results uncover the role of TET1 as a ferroptotic defensor in cancer, and suggest the translational potential of targeting the TET/GCLM axis in cancer therapy. Overall design: In order to identify the mechanism of TET1 mediated ferroptotic resistance, RNA profiles of ferroptosis-resistant (i.e., Kasumi-1), –sensitive (i.e., MV4;11), and control and TET1 overexpressed THP1 cells were generated by deep sequencing.

铁死亡（Ferroptosis）是一种以铁依赖性脂质过氧化为特征的非凋亡程序性细胞死亡，与癌症密切相关。尽管学界已对铁死亡背后的分子通路开展了大量深入研究，但决定癌细胞对铁死亡易感性差异的核心机制仍未阐明。本研究证实，介导DNA 5-羟甲基化的十-十一易位（TET）家族酶的创始成员TET1的表达水平，直接决定了癌细胞对铁死亡的易感性。在铁死亡耐药细胞中，TET1的表达水平显著高于铁死亡敏感细胞。干扰TET1的表达可显著改变细胞对铁死亡的应答反应。机制上，TET1可在其靶基因GCLM的位点促进DNA 5-羟甲基胞嘧啶（5hmC）修饰，同时激活经典谷胱甘肽（GSH）合成通路与非经典γ-谷氨酰肽积累通路，从而保护癌细胞免受铁死亡侵袭。本研究揭示了TET1在癌症中作为铁死亡防御因子的关键作用，并提示靶向TET1/GCLM轴在癌症治疗中的转化潜力。整体实验设计：为阐明TET1介导的铁死亡耐药机制，本研究通过高通量测序获取了铁死亡耐药细胞（即Kasumi-1）、铁死亡敏感细胞（即MV4;11），以及空白对照组与TET1过表达的THP1细胞的转录组图谱。