化疗耐药仍然是治疗胰腺导管腺癌（PDAC）的主要挑战。虽然放化疗已被证明对头颈鳞状细胞癌等其他肿瘤类型有效，但其在 PDAC 中的作用及其对获得性化疗耐药性的影响尚未得到充分探索。在本研究中，我们研究了吉西他滨和紫杉醇耐药的 PDAC 细胞对电离辐射 (IR) 的敏感性及其潜在机制。吉西他滨耐药 (GR) 和紫杉​​醇耐药 (PR) 克隆由 PANC-1、PATU 产生-T和SUIT2-007胰腺癌细胞系。使用克隆形成实验、SRB 实验、生物发光法评估细胞凋亡和球体生长，同时使用蛋白质印迹、XL-PCR、ROS 产生和免疫荧光评估辐射诱导的 DNA 损伤。使用蛋白质组学、蛋白质印迹、免疫荧光和 RT-qPCR 研究自噬和 Hippo 通路的调节。在 2D 和 3D 设置中，PR 细胞对 IR 更敏感，并且显示出 β-珠蛋白扩增减少，表明与 GR 相比有更多的 DNA 损伤积累或 24 小时后的野生型 (WT) 细胞。 PATU-T PR 的蛋白质组学分析表明，参与自噬和 Hippo 信号通路的激酶 MST4 蛋白高度下调。根据细胞模型，自噬和放射治疗之间存在差异关联。有趣的是，与 WT 和 GR 相比，在 SUIT2-007 PR 细胞中观察到 IR 响应后 YAP 核定位和下游 Hippo 通路靶基因表达增加。这是第一项研究 IR 靶向 PDAC 细胞的潜力化学耐药性。我们的结果表明，由于 DNA 损伤的积累更多，PR 细胞对 IR 的敏感性增强。此外，根据特定的细胞环境，辐射诱导的自噬和 Hippo 通路调节成为潜在的潜在机制，这些发现有可能为获得性化疗耐药患者的个性化治疗策略提供信息。版权所有 © 2023。由 Elsevier Inc 出版。

Chemoresistance remains a major challenge in treating pancreatic ductal adenocarcinoma (PDAC). While chemoradiation has proven effective in other tumor types, such as head-and-neck squamous cell carcinoma, its role in PDAC and its impact on acquired chemoresistance have yet to be fully explored. In this study, we investigated the sensitivity of gemcitabine- and paclitaxel-resistant PDAC cells to ionizing radiation (IR) and their underlying mechanisms.Gemcitabine-resistant (GR) and paclitaxel-resistant (PR) clones were generated from PANC-1, PATU-T and SUIT2-007 pancreatic cancer cell lines. Cell survival after radiation was assessed using clonogenic assay, SRB assay, apoptosis and spheroid growth by bioluminescence while radiation-induced DNA damage was evaluated with Western blot, XL-PCR, ROS production and immunofluorescence. Autophagy and modulation of Hippo pathway were investigated using proteomics, Western blot, immunofluorescence and RT-qPCR.In both 2D and 3D settings, PR cells were more sensitive to IR and showed decreased β-globin amplification indicating more DNA damage accumulation as compared to GR or wild-type (WT) cells after 24 hours. Proteomics analysis of PATU-T PR revealed that the protein MST4, a kinase involved in autophagy and Hippo signaling pathway, was highly downregulated. Differential association was found between autophagy and radiation treatment depending on the cell model. Interestingly, increased YAP nuclear localization and downstream Hippo pathway target gene expression were observed in in SUIT2-007 PR cells in response to IR, as compared to WT and GR.This is the first study investigating the potential of IR in targeting PDAC cells with acquired chemoresistance. Our results demonstrate that PR cells exhibit enhanced sensitivity to IR due to greater accumulation of DNA damage. Additionally, depending on the specific cellular context, radiation-induced modulation of autophagy and the Hippo pathway emerged as potential underlying mechanisms, and these findings have the potential to inform personalized treatment strategies for patients with acquired chemoresistance.Copyright © 2023. Published by Elsevier Inc.