虽然目前的靶向策略或免疫疗法能使少量患者受益，但吉西他滨仍是胰腺癌（PC）治疗的一线药物。然而，吉西他滨的耐药现象普遍存在且会影响患者的长期生存。在此，我们确定泛素连接酶E2T（UBE2T）为一种潜在的治疗靶点，以应对PC中吉西他滨耐药现象。蛋白质组学和代谢组学相结合，以检查UBE2T对嘧啶代谢的重构效应。使用具有Ube2t的条件性敲除的自发性PC小鼠（LSL-KrasG12D / +，LSL-Trp53R172H / +，Pdx1-Cre；KPC），器官样和大规模的临床样本来确定UBE2T对吉西他滨疗效的影响。器官样，来源于患者的异种移植（PDX）和KPC小鼠被用来检查UBE2T抑制剂和吉西他滨的联合疗效。删除Ube2t的自发性PC小鼠在吉西他滨治疗后表现出明显的生存优势，并且UBE2T水平与临床患者的吉西他滨耐药性呈正相关。机制上，UBE2T催化RING1介导的p53泛素化作用，减轻RRM1和RRM2的转录抑制，导致嘧啶生物合成的无限制和复制应激的减轻。此外，通过器官样高通量化合物库筛选，识别了没食子酸五聚体葡萄糖（PGG）作为一种有效的UBE2T抑制剂和吉西他滨敏化剂。吉西他滨和PGG的联合能够减缓PDX模型的肿瘤生长并延长自发性PC小鼠的长期生存。总之，UBE2T介导的p53降解促进嘧啶生物合成并减轻复制应激，从而使PC耐受吉西他滨。本研究为通过靶向UBE2T并开发有希望的吉西他滨敏化剂来改善PC生存提供了机会。版权所有© 2023 AGA研究所。由Elsevier公司出版。保留所有权利。

Although small patient subsets benefit from current targeted strategies or immunotherapy, gemcitabine remains the first-line drug for pancreatic cancer (PC) treatment. However, gemcitabine resistance is widespread and compromises long-term survival. Here, we identified ubiquitin-conjugating enzyme E2T (UBE2T) as a potential therapeutic target to combat gemcitabine resistance in PC.Proteomics and metabolomics were combined to examine the effect of UBE2T on pyrimidine metabolism remodeling. Spontaneous PC mice (LSL-KrasG12D/+, LSL-Trp53R172H/+, Pdx1-Cre; KPC) with Ube2t-conditional knockout, organoids, and large-scale clinical samples were used to determine the effect of UBE2T on gemcitabine efficacy. Organoids, patient-derived xenografts (PDX), and KPC mice were used to examine the efficacy of the combination of a UBE2T inhibitor and gemcitabine.Spontaneous PC mice with Ube2t deletion had a marked survival advantage following gemcitabine treatment, and UBE2T levels were positively correlated with gemcitabine resistance in clinical patients. Mechanistically, UBE2T catalyzes RING1-mediated ubiquitination of p53 and relieves the transcriptional repression of RRM1 and RRM2, resulting in unrestrained pyrimidine biosynthesis and alleviation of replication stress. Additionally, high-throughput compound library screening using organoids identified pentagalloylglucose (PGG) as a potent UBE2T inhibitor and gemcitabine sensitizer. The combination of gemcitabine and PGG diminished tumor growth in PDX models and prolonged long-term survival in spontaneous PC mice.Collectively, UBE2T-mediated p53 degradation confers PC gemcitabine resistance by promoting pyrimidine biosynthesis and alleviating replication stress. This study offers an opportunity to improve PC survival by targeting UBE2T and develop a promising gemcitabine sensitizer in clinical translation setting.Copyright © 2023 AGA Institute. Published by Elsevier Inc. All rights reserved.