Sirtuin 3-mediated delactylation of malic enzyme 2 disrupts redox balance and inhibits colorectal cancer growth.

IF 4.9 2区医学 Q2 CELL BIOLOGY

Cellular Oncology Pub Date : 2025-04-07 DOI:10.1007/s13402-025-01058-5

Chaoqun Li, Cun Ge, Qingwen Wang, Peng Teng, Heyuan Jia, Surui Yao, Zhaohui Huang

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引用次数: 0

Abstract

Purpose: Post-translational modifications, such as lactylation, are emerging as critical regulators of metabolic enzymes in cancer progression. Mitochondrial malic enzyme 2 (ME2), a key enzyme in the TCA cycle, plays a pivotal role in maintaining redox homeostasis and supporting tumor metabolism. However, the functional significance of ME2 lactylation and its regulatory mechanisms remain unclear. This study investigates the role of ME2 K352 lactylation in modulating enzymatic activity, redox balance, and tumor progression.

Methods: Immunoprecipitation and western blotting were used to assess ME2 lactylation and its interaction with Sirtuin 3 (SIRT3). Mass spectrometry identified the lactylation site on ME2. Enzymatic activity was measured using NADH production assays. The functional effects of ME2 K352 lactylation were analyzed by measuring ROS levels, NADP⁺/NADPH ratios, metabolic intermediates, and mitochondrial respiration parameters. Cell proliferation was evaluated via CCK-8 and colony formation assays. Xenograft tumor models and Ki-67 immunohistochemical staining were used to assess tumor growth and proliferation in vivo.

Results: Mass spectrometry identified K352 as the primary lactylation site on ME2. Sodium lactate treatment enhanced ME2 lactylation and enzymatic activity, while SIRT3-mediated delactylation at K352 reduced ME2 activity, disrupting redox homeostasis. Cells expressing the K352R mutant exhibited elevated ROS levels, higher NADP⁺/NADPH ratios, and altered levels of metabolic intermediates, including increased malate and lactate with reduced pyruvate. Additionally, re-expression of ME2 K352R in HCT116 cells significantly impaired proliferation and colony formation. In vivo, xenograft models demonstrated that ME2 K352R expression suppressed tumor growth, as evidenced by reduced tumor volume, weight, and Ki-67 staining.

Conclusions: This study reveals that ME2 K352 lactylation is a critical regulatory mechanism that modulates enzymatic activity, mitochondrial function, and tumor progression. SIRT3-mediated delactylation of ME2 K352 disrupts redox homeostasis and inhibits tumor growth. These findings highlight the potential of targeting ME2 lactylation as a therapeutic strategy in cancer treatment.

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Sirtuin 3介导的苹果酸酶2去乙酰化破坏氧化还原平衡并抑制结直肠癌的生长。

目的：乳化等翻译后修饰正在成为癌症进展过程中代谢酶的关键调节因子。线粒体苹果酸酶 2（ME2）是 TCA 循环中的一种关键酶，在维持氧化还原平衡和支持肿瘤代谢方面发挥着关键作用。然而，ME2乳化的功能意义及其调控机制仍不清楚。本研究探讨了ME2 K352乳化在调节酶活性、氧化还原平衡和肿瘤进展中的作用：方法：采用免疫沉淀和免疫印迹法评估 ME2 乳化及其与 Sirtuin 3（SIRT3）的相互作用。质谱法确定了 ME2 上的乳化位点。使用 NADH 生成试验测量了酶活性。通过测量 ROS 水平、NADP⁺/NADPH 比率、代谢中间产物和线粒体呼吸参数，分析了 ME2 K352 乳酰化的功能影响。细胞增殖通过 CCK-8 和集落形成试验进行评估。异种移植肿瘤模型和 Ki-67 免疫组化染色用于评估体内肿瘤的生长和增殖：结果：质谱鉴定出K352是ME2上的主要乳化位点。乳酸钠处理增强了ME2的乳化作用和酶活性，而SIRT3介导的K352脱乳作用降低了ME2的活性，破坏了氧化还原平衡。表达 K352R 突变体的细胞表现出 ROS 水平升高、NADP⁺/NADPH 比率升高以及代谢中间产物水平改变，包括苹果酸和乳酸增加而丙酮酸减少。此外，在 HCT116 细胞中重新表达 ME2 K352R 会显著影响细胞增殖和集落形成。在体内，异种移植模型显示 ME2 K352R 的表达抑制了肿瘤的生长，肿瘤体积、重量和 Ki-67 染色的减少都证明了这一点：这项研究揭示了 ME2 K352 乳化是一种关键的调控机制，可调节酶活性、线粒体功能和肿瘤进展。SIRT3 介导的 ME2 K352 脱乳作用会破坏氧化还原平衡并抑制肿瘤生长。这些发现凸显了靶向 ME2 乳化作为癌症治疗策略的潜力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Cellular Oncology ONCOLOGY-CELL BIOLOGY

CiteScore

10.30

自引率

1.50%

发文量

审稿时长

12 months

期刊介绍： The Official Journal of the International Society for Cellular Oncology Focuses on translational research Addresses the conversion of cell biology to clinical applications Cellular Oncology publishes scientific contributions from various biomedical and clinical disciplines involved in basic and translational cancer research on the cell and tissue level, technical and bioinformatics developments in this area, and clinical applications. This includes a variety of fields like genome technology, micro-arrays and other high-throughput techniques, genomic instability, SNP, DNA methylation, signaling pathways, DNA organization, (sub)microscopic imaging, proteomics, bioinformatics, functional effects of genomics, drug design and development, molecular diagnostics and targeted cancer therapies, genotype-phenotype interactions. A major goal is to translate the latest developments in these fields from the research laboratory into routine patient management. To this end Cellular Oncology forms a platform of scientific information exchange between molecular biologists and geneticists, technical developers, pathologists, (medical) oncologists and other clinicians involved in the management of cancer patients. In vitro studies are preferentially supported by validations in tumor tissue with clinicopathological associations.