Yang Long, Niu Kunwei, Wang Jianlin, Shen Weiwei, Jiang Rui, Liu Lu, Song Wenjie, Wang Xudan, Zhang Xuan, Zhang Ruohan, Wei Dan, Fan Ming, Jia Lintao, Tao Kaishan
Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Department of Oncology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China.
J Hepatol. 2024 Oct;81(4):651-666. doi: 10.1016/j.jhep.2024.04.010. Epub 2024 Apr 27.
BACKGROUND & AIMS: Intrahepatic cholangiocarcinoma (iCCA) is a fatal malignancy of the biliary system. The lack of a detailed understanding of oncogenic signaling or global gene expression alterations has impeded clinical iCCA diagnosis and therapy. The role of protein lactylation, a newly unraveled post-translational modification that orchestrates gene expression, remains largely elusive in the pathogenesis of iCCA.
Proteomics analysis of clinical iCCA specimens and adjacent tissues was performed to screen for proteins aberrantly lactylated in iCCA. Mass spectrometry, macromolecule interaction and cell behavioral studies were employed to identify the specific lactylation sites on the candidate protein(s) and to decipher the downstream mechanisms responsible for iCCA development, which were subsequently validated using a xenograft tumor model and clinical samples.
Nucleolin (NCL), the most abundant RNA-binding protein in the nucleolus, was identified as a functional lactylation target that correlates with iCCA occurrence and progression. NCL was lactylated predominantly at lysine 477 by the acyltransferase P300 in response to a hyperactivity of glycolysis, and promoted the proliferation and invasion of iCCA cells. Mechanistically, lactylated NCL bound to the primary transcript of MAP kinase-activating death domain protein (MADD) and led to efficient translation of MADD by circumventing alternative splicing that generates a premature termination codon. NCL lactylation, MADD translation and subsequent ERK activation promoted xenograft tumor growth and were associated with overall survival in patients with iCCA.
NCL is lactylated to upregulate MADD through an RNA splicing-dependent mechanism, which potentiates iCCA pathogenesis via the MAPK pathway. Our findings reveal a novel link between metabolic reprogramming and canonical tumor-initiating events, and uncover biomarkers that can potentially be used for prognostic evaluation or targeted treatment of iCCA.
Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive liver malignancy with largely uncharacterized pathogenetic mechanisms. Herein, we demonstrated that glycolysis promotes P300-catalyzed lactylation of nucleolin, which upregulates MAP kinase-activating death domain protein (MADD) through precise mRNA splicing and activates ERK signaling to drive iCCA development. These findings unravel a novel link between metabolic rewiring and canonical oncogenic pathways, and reveal new biomarkers for prognostic assessment and targeting of clinical iCCA.
肝内胆管癌（iCCA）是一种致命的胆道系统恶性肿瘤。对致癌信号或整体基因表达改变缺乏详细了解阻碍了iCCA的临床诊断和治疗。蛋白质乳酰化是一种新发现的协调基因表达的翻译后修饰，其在iCCA发病机制中的作用在很大程度上仍不清楚。
对临床iCCA标本和相邻组织进行蛋白质组学分析，以筛选在iCCA中异常乳酰化的蛋白质。采用质谱、大分子相互作用和细胞行为研究来确定候选蛋白质上的特定乳酰化位点，并破译iCCA发生发展的下游机制，随后使用异种移植肿瘤模型和临床样本进行验证。
核仁素（NCL）是核仁中最丰富的RNA结合蛋白，被确定为与iCCA发生和进展相关的功能性乳酰化靶点。在糖酵解亢进的情况下，NCL主要在赖氨酸477处被酰基转移酶P300乳酰化，并促进iCCA细胞的增殖和侵袭。机制上，乳酰化的NCL与丝裂原活化死亡结构域蛋白（MADD）的初级转录本结合，并通过规避产生提前终止密码子的可变剪接导致MADD的有效翻译。NCL乳酰化、MADD翻译及随后的ERK激活促进了异种移植肿瘤的生长，并与iCCA患者的总生存期相关。
NCL通过RNA剪接依赖机制被乳酰化以上调MADD，通过MAPK途径增强iCCA发病机制。我们的研究结果揭示了代谢重编程与经典肿瘤起始事件之间的新联系，并发现了可潜在用于iCCA预后评估或靶向治疗的生物标志物。
肝内胆管癌（iCCA）是一种侵袭性很强的肝脏恶性肿瘤，其发病机制在很大程度上尚不明确。在此，我们证明糖酵解促进P300催化的核仁素乳酰化，通过精确的mRNA剪接上调丝裂原活化死亡结构域蛋白（MADD）并激活ERK信号传导以驱动iCCA发展。这些发现揭示了代谢重塑与经典致癌途径之间的新联系，并揭示了用于临床iCCA预后评估和靶向治疗的新生物标志物。
