该研究全面探讨了烟酰胺N-甲基转移酶（NNMT）的表达与膀胱尿路上皮癌（UBC）临床结果之间的关联，以及癌症相关成纤维细胞（CAF）中NNMT调节肿瘤进展和免疫治疗的分子机制对膀胱癌样本进行单细胞转录组分析、免疫组织化学和免疫荧光测定，以验证 NNMT 表达与临床结果之间的关系。建立了一系列实验，包括染色质免疫沉淀测定、液相色谱串联质谱测定、CRISPR-Cas9（成簇规则间隔短回文重复序列和CRISPR相关蛋白9）敲除以及体内模型，以确定分子NNMT 在 UBC 的 CAF 中的功能。我们证明，CAF 中烟酰胺腺嘌呤二核苷酸 (NAD) 代谢酶 NNMT (NNMT CAF) 的表达升高与对程序性死亡配体 1 (PD-L1) 阻断免疫疗法的无反应显着相关研究人员对 UBC 患者进行了研究，并在两个独立的大型队列中预测了 UBC 的不良预后。在 UBC 小鼠模型中，使用抑制剂 5-Amino-1-methylquinolinium iodide 靶向 NNMT 显着减少肿瘤生长，并增强抗 PD-L1 抗体的细胞凋亡作用。从机制上讲，NNMT CAF 通过血清淀粉样蛋白 A (SAA) 的表观遗传重编程来招募肿瘤相关巨噬细胞，以驱动肿瘤细胞增殖并赋予对程序性死亡 1/PD-L1 阻断免疫疗法的抵抗力。NNMT CAF 与 PD 无反应显着相关UBC 患者的 L1 阻断免疫治疗。 NNMT 升高，特别是在 CAF 中，上调 SAA 表达并增强肿瘤微环境中巨噬细胞的募集和分化，从而直接或间接促进肿瘤进展并赋予膀胱癌免疫治疗耐药性。© 作者（或其雇主） )) 2024。根据 CC BY-NC 允许重复使用。禁止商业再利用。请参阅权利和权限。英国医学杂志出版。

This study comprehensively investigates the association between the expression of nicotinamide N-methyltransferase (NNMT) and clinical outcomes of urothelial bladder cancer (UBC), as well as the molecular mechanisms by which NNMT in cancer-associated fibroblast (CAF) modulates tumor progression and immunotherapy resistance in UBC.Single-cell transcriptomic analyses, immunohistochemical and immunofluorescence assays were performed on bladder cancer samples to validate the relationship between NNMT expression and clinical outcomes. A series of experiments, including chromatin immunoprecipitation assay, liquid chromatography tandem mass spectrometry assay, and CRISPR‒Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated protein 9) knockout, together with in vivo models, have been established to determine the molecular functions of NNMT in CAFs in UBC.We demonstrated that elevated expression of the nicotinamide adenine dinucleotide (NAD+) metabolism enzyme NNMT in CAFs (NNMT+ CAFs) was significantly associated with non-response to programmed death-ligand 1 (PD-L1) blockade immunotherapy in patients with UBC and predicted the unfavorable prognosis of UBC in two independent large cohorts. Targeting NNMT using the inhibitor 5-Amino-1-methylquinolinium iodide significantly reduced tumor growth and enhanced the apoptotic effects of the anti-PD-L1 antibody in UBC mouse models. Mechanistically, NNMT+ CAFs recruit tumor-associated macrophages via epigenetic reprogramming of serum amyloid A (SAA) to drive tumor cell proliferation and confer resistance to programmed death-1/PD-L1 blockade immunotherapy.NNMT+ CAFs were significantly associated with non-response to PD-L1 blockade immunotherapy in patients with UBC. Elevated NNMT, specifically in CAFs, upregulates SAA expression and enhances the recruitment and differentiation of macrophages in the tumor microenvironment, thereby directly or indirectly promoting tumor progression and conferring resistance to immunotherapies in bladder cancer.© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.