PO.ET03.04 · 实验与分子治疗
IDH1抑制增强吉西他滨在胰腺导管腺癌中的疗效
IDH1 inhibition potentiates gemcitabine efficacy in pancreatic ductal adenocarcinoma
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：胰腺导管腺癌（PDAC）是最具侵袭性的癌症之一，5年生存率约为13%。吉西他滨仍是标准的一线化疗药物，但超过80%的患者会产生耐药，限制了其临床获益。野生型异柠檬酸脱氢酶1（wt-IDH1）在PDAC中高表达，催化异柠檬酸转化为α-酮戊二酸以及NADPH的生成，以支持线粒体代谢。艾伏尼布（AG-120）是一种FDA批准的口服变构抑制剂，最初针对突变型IDH1开发，但在PDAC典型的营养匮乏和低镁条件下也能有效抑制wt-IDH1。这种抑制降低NADPH，增加化疗诱导的活性氧（ROS），并显著损害耐药细胞的存活，为AG-120与吉西他滨联合以克服化疗耐药提供了机制依据。
方法：使用PicoGreen dsDNA检测法在吉西他滨耐药的PDAC细胞系（MIA PaCa-2和BxPC-3）中评估了AG-120与吉西他滨的协同效应。在功能实验中应用最佳药物剂量，包括划痕愈合、迁移/侵袭和克隆形成实验，以评估对细胞生长和运动性的影响。在机制上，wt-IDH1抑制降低NADPH并损害线粒体代谢，因此在处理后测量细胞内ROS水平以评估氧化应激。进一步使用Seahorse检测法检查线粒体功能。通过RNA测序进行转录组分析，结合qRT-PCR和Western blot验证，以确定驱动协同反应的关键通路。在PDAC异种移植模型中进一步确认了联合治疗的体内疗效。
结果：AG-120与吉西他滨联合在吉西他滨耐药的PDAC细胞系中对细胞增殖、迁移、侵袭和克隆形成表现出协同抗癌效应。对IDH1抑制下调基因的转录组分析显示OXPHOS通路显著富集（富集评分 = 2.32，P <0.01），并得到Seahorse检测法显示线粒体OXPHOS受抑制的支持。在机制上，吉西他滨耐药细胞表现出镁内流转运体TRPM7的显著上调，TRPM7是哺乳动物细胞中镁稳态的重要调控因子，提示对镁的敏感性和依赖性增加。这些发现提示，低镁条件增强了耐药PDAC细胞对wt-IDH1抑制的反应性，促成了所观察到的联合治疗的协同抗癌效应。
结论：本研究提供了关于AG-120如何通过靶向wt-IDH1和调节OXPHOS通路克服PDAC细胞吉西他滨耐药的机制见解，突显了一种改善治疗结果的潜在治疗策略。
查看英文原文 English abstract
Background: Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive cancers, with a 5-year survival rate of approximately 13%. Gemcitabine remains standard first-line chemotherapy, over 80% of patients develop resistance, limiting its clinical benefit. Wild-type isocitrate dehydrogenase 1 (wt-IDH1) is highly expressed in PDAC, catalyzing the conversion of isocitrate to alpha-ketoglutarate and NADPH to support mitochondrial metabolism. Ivosidenib (AG-120) is an FDA-approved oral allosteric inhibitor originally developed for mutant IDH1, but it also effectively inhibits wt-IDH1 under nutrient-deprived and low-magnesium conditions typical of PDAC. This inhibition reduces NADPH, increases chemotherapy-induced reactive oxygen species (ROS), and markedly impairs the survival of resistant cells, providing a mechanistic rationale for combining AG-120 with gemcitabine to overcome chemoresistance.
Methods: The synergistic effect of AG-120 and gemcitabine was evaluated in gemcitabine-resistant PDAC cell lines (MIA PaCa-2 and BxPC-3) using the PicoGreen dsDNA assay. Optimal drug doses were applied in functional assays, including wound healing, migration/invasion, and colony formation, to evaluate effects on cell growth and motility. Mechanistically, wt-IDH1 inhibition reduces NADPH and impairs mitochondrial metabolism, intracellular ROS levels were measured following treatment to evaluate oxidative stress. Mitochondrial function was further examined using Seahorse assays. Transcriptomic profiling via RNA sequencing, combined with qRT-PCR and Western blot validation, was performed to identify key pathways driving the synergistic response. The efficacy of the combination therapy was further confirmed in vivo using a PDAC xenograft model.
Results: The combination of AG-120 and gemcitabine exhibited synergistic anticancer effects on cell proliferation, migration, invasion, and colony formation in gemcitabine-resistant PDAC cell lines. Transcriptomic analysis of genes downregulated by IDH1 inhibition revealed significant enrichment of OXPHOS pathways (enrich score = 2.32, P <0.01), supported by Seahorse assays showing suppression of mitochondrial OXPHOS. Mechanistically, gemcitabine-resistant cells exhibited a marked upregulation of the magnesium influx transporter TRPM7, an essential regulator of magnesium homeostasis in mammalian cells, suggesting increased sensitivity and dependency on magnesium. These findings suggest that low-magnesium conditions enhance the responsiveness of resistant PDAC cells to wt-IDH1 inhibition, contributing to the observed synergistic anticancer effect of the combination therapy.
Conclusion: This study provides mechanistic insight into how AG-120 overcomes gemcitabine resistance in PDAC cells by targeting wt-IDH1 and modulating the OXPHOS pathway, highlighting a potential therapeutic strategy to improve treatment outcomes.
利益披露 Disclosure
Y. Li, None..
W. Weng, None..
A. Goel, None.