抗编程死亡-1（anti-PD-1）免疫治疗在提高晚期黑色素瘤患者的生存率方面显示出了有希望的表现，其疗效与程序化细胞死亡配体-1（PD-L1）表达密切相关。然而，低临床疗效和药物抵抗仍然是主要挑战。尽管三羧酸循环（TCA）向糖酵解的代谢变化是癌细胞的特征，但越来越多的证据表明，TCA循环在肿瘤发生和治疗中起着重要作用。通过核磁共振（NMR）光谱测定了黑色素瘤患者血浆中的代谢物水平。通过B16F10肿瘤携带的小鼠实验评估了丙酮酸脱氢酶亚单位1（PDHA1）和2-酮戊二酸脱氢酶（OGDH）对免疫治疗的影响。流式细胞术分析了免疫微环境。RNA测序分析了CPI613治疗的黑色素瘤细胞的全局转录组变化。通过定量实时聚合酶链反应（qRT-PCR）、免疫印迹、双荧光素酶报告基因、染色质免疫沉淀-定量PCR（ChIP-qPCR）和Seahorse测定验证了PDHA1/OGDH-ATF3信号通路调节PD-L1和糖酵解的作用。通过临床数据库和单细胞RNA测序（ScRNA-Seq）验证了PDHA1/OGDH-ATF3-糖酵解与黑色素瘤抗PD-1免疫治疗疗效的关系。在我们的研究中，结果显示通过NMR技术检测到与糖酵解和TCA循环相关的代谢物在黑色素瘤患者血浆中发生了显著变化，PDHA1和OGDH，作为调节TCA循环的关键酶，在黑色素瘤中显著升高，并与抗PD-1疗效呈负相关，通过临床数据库分析和ScRNA-Seq验证了这一点。通过shRNA或CPI613药物抑制PDHA1和OGDH显著减弱了黑色素瘤的进展，并改善了抗PD-1对黑色素瘤的治疗疗效。最重要的是，抑制TCA循环显著提高了PD-L1的表达和糖酵解通量，通过AMPK-CREB-ATF3信号通路。综上所述，我们的研究结果展示了TCA循环在免疫检查点阻断中的作用，并为黑色素瘤治疗中的抗PD-1免疫治疗提供了新的组合策略。© 作者（或雇主）2023年。根据CC BY-NC许可证可重新使用。不得进行商业再利用。由BMJ出版。

anti-Programmed Death-1 (anti-PD-1) immunotherapy has shown promising manifestation in improving the survival rate of patients with advanced melanoma, with its efficacy closely linked to Programmed cell death-Ligand 1 (PD-L1) expression. However, low clinical efficacy and drug resistance remain major challenges. Although the metabolic alterations from tricarboxylic acid (TCA) cycle to glycolysis is a hallmark in cancer cells, accumulating evidence demonstrating TCA cycle plays critical roles in both tumorigenesis and treatment.The plasma levels of metabolites in patients with melanoma were measured by nuclear magnetic resonance (NMR) spectroscopy. The effect of pyruvate dehydrogenase subunit 1 (PDHA1) and oxoglutarate dehydrogenase (OGDH) on immunotherapy was performed by B16F10 tumor-bearing mice. Flow cytometry analyzed the immune microenvironment. RNA sequencing analyzed the global transcriptome alterations in CPI613-treated melanoma cells. The regulation of PD-L1 and glycolysis by PDHA1/OGDH-ATF3 signaling were confirmed by Quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, dual-luciferase reporter gene, Chromatin immunoprecipitation (ChIP)-quantitative PCR and Seahorse assay. The relationship between PDHA1/OGDH-ATF3-glycolysis and the efficacy of melanoma anti-PD-1 immunotherapy was verified in the clinical database and single-cell RNA-seq (ScRNA-Seq).In our study, the results showed that significant alterations in metabolites associated with glycolysis and the TCA cycle in plasma of patients with melanoma through NMR technique, and then, PDHA1 and OGDH, key enzymes for regulation TCA cycle, were remarkable raised in melanoma and negatively related to anti-PD-1 efficacy through clinical database analysis as well as ScRNA-Seq. Inhibition of PDHA1 and OGDH by either shRNA or pharmacological inhibitor by CPI613 dramatically attenuated melanoma progression as well as improved the therapeutic efficacy of anti-PD-1 against melanoma. Most importantly, suppression of TCA cycle remarkably raises PD-L1 expression and glycolysis flux through AMPK-CREB-ATF3 signaling.Taken together, our results demonstrated the role of TCA cycle in immune checkpoint blockade and provided a novel combination strategy for anti-PD-1 immunotherapy in melanoma treatment.© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.