Niu Kaifeng, Chen Zixiang, Li Mengge, Ma Guannan, Deng Yuchun, Zhang Ji, Wei Di, Wang Jiaqi, Zhao Yongliang
China National Center for Bioinformation, Beijing, 100101, China; Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
China National Center for Bioinformation, Beijing, 100101, China; Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
Redox Biol. 2025 Feb;79:103479. doi: 10.1016/j.redox.2024.103479. Epub 2024 Dec 19.
Lactate-mediated lactylation on target proteins is recently identified as the novel posttranslational modification with profound biological functions. RNA 5-methylcytosine (mC) modification possesses dynamic and reversible nature, suggesting that activity of its methyltransferase NSUN2 is actively regulated. However, how NSUN2 activity is response to acidic condition in tumor microenvironment and then regulates cancer cell survival remain to be clarified. Here, we demonstrate that NSUN2 activity is enhanced by lactate-mediated lactylation at lysine 508, which then targets glutamate-cysteine ligase catalytic subunit (GCLC) mRNA to facilitates GCLC mC formation and mRNA stabilization. The activated GCLC induces higher level of intracellular GSH accompanied by decreased lipid peroxidation and resistant phenotype to ferroptosis induction by doxorubicin (Dox) in gastric cancer cells. Specifically, the effect of NSUN2 lactylation-GCLC-GSH pathway is nearly lost when NSUN2 K508R or GCLC C-A mutant (five cytosine sites) was introduced into the cancer cells. We further identify the catalytic subunit N-α-acetyltransferase 10 (NAA10) as the lactytransferase of NSUN2, and lactate treatment substantially enhances their association and consequent NSUN2 activation. Taken together, our findings convincingly elucidate the signaling axis of NAA10-NSUN2-GCLC that potently antagonizes the ferroptosis under acidic condition, and therefore, targeting NSUN2 lactylation might be an effective strategy in improving the prognosis of cancer patients.
乳酸介导的靶蛋白乳酰化最近被确定为一种具有深远生物学功能的新型翻译后修饰。RNA 5-甲基胞嘧啶（mC）修饰具有动态可逆性，这表明其甲基转移酶NSUN2的活性受到积极调控。然而，NSUN2活性如何响应肿瘤微环境中的酸性条件进而调节癌细胞存活仍有待阐明。在此，我们证明NSUN2的活性通过赖氨酸508处的乳酸介导的乳酰化而增强，随后靶向谷氨酸-半胱氨酸连接酶催化亚基（GCLC）mRNA以促进GCLC的mC形成和mRNA稳定。活化的GCLC诱导细胞内谷胱甘肽（GSH）水平升高，同时降低脂质过氧化，并使胃癌细胞对阿霉素（Dox）诱导的铁死亡产生抗性表型。具体而言，当将NSUN2 K508R或GCLC C-A突变体（五个胞嘧啶位点）引入癌细胞时，NSUN2乳酰化-GCLC-GSH途径的作用几乎丧失。我们进一步确定催化亚基N-α-乙酰转移酶10（NAA10）为NSUN2的乳酰转移酶，乳酸处理可显著增强它们的结合并进而激活NSUN2。综上所述，我们的研究结果令人信服地阐明了NAA10-NSUN2-GCLC信号轴在酸性条件下有效拮抗铁死亡，因此，靶向NSUN2乳酰化可能是改善癌症患者预后的有效策略。
