Background: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, largely due to its dense fibrotic stroma that promotes drug resistance and tumor progression. While patient-derived organoids (PDOs) have emerged as promising tools for modeling PDAC and evaluating therapeutic responses, the current PDO models grown in soft matrices fail to replicate the tumor’s stiff extracellular matrix (ECM), limiting their predictive value for advanced disease. Methods: We developed a biomimetic model using gelatin-based matrices of varying stiffness, achieved through modulated transglutaminase crosslinking rates, to better simulate the desmoplastic PDAC microenvironment. Using this platform, we investigated organoid morphology, proliferation, and chemoresistance to gemcitabine (Gem) and its lipophilic derivative, 4-N-stearoyl gemcitabine (Gem-S). Mechanistic studies focused on the interplay between ECM stiffness, hypoxia-inducible factor (HIF) expression, and the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in drug resistance. Results: PDAC organoids in stiffer matrices demonstrated enhanced stemness features, including rounded morphology and elevated cancer stem cell (CSC) marker expression. Matrix stiffness-induced gemcitabine resistance correlated with the upregulation of ABC transporters and oxidative stress adaptive responses. While gemcitabine activated Nrf2 expression, promoting oxidative stress mitigation, Gem-S suppressed Nrf2 levels and induced oxidative stress, leading to increased reactive oxygen species (ROS) and enhanced cell death. Both compounds reduced HIF expression, with gemcitabine showing greater efficacy. Conclusions: Our study reveals ECM stiffness as a critical mediator of PDAC chemoresistance through the promotion of stemness and modulation of Nrf2 and HIF pathways. Gem-S demonstrates promise in overcoming gemcitabine resistance by disrupting Nrf2-mediated adaptive responses and inducing oxidative stress. These findings underscore the importance of biomechanically accurate tumor models and suggest that dual targeting of mechanical and oxidative stress pathways may improve PDAC treatment outcomes.
背景：胰腺导管腺癌（PDAC）仍是最致命的恶性肿瘤之一，这主要归因于其致密的纤维化间质会促进耐药性和肿瘤进展。虽然患者来源的类器官已成为模拟PDAC和评估治疗反应的有前景工具，但目前生长在软基质中的PDO模型无法复制肿瘤的僵硬细胞外基质，限制了其对晚期疾病的预测价值。 方法：我们开发了一种仿生模型，通过调节转谷氨酰胺酶交联速率，使用不同硬度的明胶基质来更好地模拟促纤维增生性PDAC微环境。利用该平台，我们研究了类器官的形态、增殖以及对吉西他滨及其亲脂性衍生物4-N-硬脂酰吉西他滨的化疗耐药性。机制研究聚焦于ECM硬度、缺氧诱导因子表达与核因子E2相关因子2通路在耐药性中的相互作用。 结果：在较硬基质中培养的PDAC类器官表现出增强的干性特征，包括圆形形态和升高的癌症干细胞标志物表达。基质硬度诱导的吉西他滨耐药性与ABC转运蛋白上调和氧化应激适应性反应相关。虽然吉西他滨激活Nrf2表达并促进氧化应激缓解，但Gem-S抑制Nrf2水平并诱导氧化应激，导致活性氧增加和细胞死亡增强。两种化合物均降低HIF表达，其中吉西他滨显示出更大效力。 结论：我们的研究揭示ECM硬度通过促进干性特征和调节Nrf2与HIF通路，成为PDAC化疗耐药的关键介质。Gem-S通过破坏Nrf2介导的适应性反应和诱导氧化应激，展现出克服吉西他滨耐药性的潜力。这些发现强调了生物力学精确肿瘤模型的重要性，并提示同时靶向机械应激和氧化应激通路可能改善PDAC治疗结果。
ECM Stiffness-Induced Redox Signaling Enhances Stearoyl Gemcitabine Efficacy in Pancreatic Cancer
肿瘤(癌症)患者之家