Dent Paul, Booth Laurence, Roberts Jane L, Poklepovic Andrew, Hancock John F
Departments of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, United States.
Departments of Medicine, Virginia Commonwealth University, Richmond, VA, United States.
Front Oncol. 2020 Jan 28;10:22. doi: 10.3389/fonc.2020.00022. eCollection 2020.
Previously we demonstrated that the multiple sclerosis drug dimethyl fumarate (DMF) and its plasma breakdown product MMF could interact with chemotherapeutic agents to kill both GBM cells and activated microglia. The trial NCT02337426 demonstrated the safety of DMF in newly diagnosed GBM patients when combined with the standard of care Stupp protocol. We hypothesized that another multiple sclerosis drug, fingolimod (FTY720) would synergize with MMF to kill GBM cells. MMF and fingolimod interacted in a greater than additive fashion to kill PDX GBM isolates. MMF and fingolimod radiosensitized glioma cells and enhanced the lethality of temozolomide. Exposure to [MMF + fingolimod] activated an ATM-dependent toxic autophagy pathway, enhanced protective endoplasmic reticulum stress signaling, and inactivated protective PI3K, STAT, and YAP function. The drug combination reduced the expression of protective c-FLIP-s, MCL-1, BCL-XL, and in parallel caused cell-surface clustering of the death receptor CD95. Knock down of CD95 or over-expression of c-FLIP-s or BCL-XL suppressed killing. Fingolimod and MMF interacted in a greater than additive fashion to rapidly enhance reactive oxygen species production and over-expression of either thioredoxin or super-oxide dismutase two significantly reduced the drug-induced phosphorylation of ATM, autophagosome formation and [MMF + fingolimod] lethality. In contrast, the production of ROS was only marginally reduced in cells lacking ATM, CD95, or Beclin1. Collectively, our data demonstrate that the primary generation of ROS by [MMF + fingolimod] plays a key role, via the induction of toxic autophagy and death receptor signaling, in the killing of GBM cells.
此前我们证明，多发性硬化症药物富马酸二甲酯（DMF）及其血浆分解产物单甲基富马酸（MMF）可与化疗药物相互作用，杀死胶质母细胞瘤（GBM）细胞和活化的小胶质细胞。试验NCT02337426证明，DMF与标准治疗方案Stupp方案联合使用时，对新诊断的GBM患者具有安全性。我们假设另一种多发性硬化症药物芬戈莫德（FTY720）会与MMF协同作用杀死GBM细胞。MMF和芬戈莫德以大于相加的方式相互作用，杀死PDX GBM分离株。MMF和芬戈莫德使胶质瘤细胞对辐射敏感，并增强替莫唑胺的致死性。暴露于[MMF + 芬戈莫德]激活了一种依赖ATM的毒性自噬途径，增强了保护性内质网应激信号，并使保护性PI3K、STAT和YAP功能失活。该药物组合降低了保护性c-FLIP-s、MCL-1、BCL-XL的表达，同时导致死亡受体CD95的细胞表面聚集。敲低CD95或过表达c-FLIP-s或BCL-XL可抑制杀伤作用。芬戈莫德和MMF以大于相加的方式相互作用，迅速增强活性氧的产生，而过表达硫氧还蛋白或超氧化物歧化酶两种酶可显著降低药物诱导的ATM磷酸化、自噬体形成和[MMF + 芬戈莫德]的致死性。相比之下，在缺乏ATM、CD95或Beclin1的细胞中，活性氧的产生仅略有减少。总体而言，我们的数据表明，[MMF + 芬戈莫德]产生的活性氧主要通过诱导毒性自噬和死亡受体信号传导，在杀死GBM细胞中起关键作用。
