Endoplasmic reticulum stress-inducing drugs sensitize glioma cells to temozolomide through downregulation of MGMT, MPG, and Rad51
Endoplasmic reticulum stress-inducing drugs sensitize glioma cells to temozolomide through downregulation of MGMT, MPG, and Rad51
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DOI：
10.1093/neuonc/now022
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发表时间：
2016-08-01
期刊：
影响因子：
15.9
通讯作者：
Alonso, Marta M.
中科院分区：
文献类型：
--
作者：
Xipell, Enric;Aragon, Tomas;Alonso, Marta M.
内质网（ER）应激是由蛋白质错误折叠失衡引起的，并被认为是一种治疗策略。内质网应激激活未折叠蛋白反应，导致复杂的细胞反应，包括内质网异常蛋白降解的上调，目的是解决应激。o -6-甲基鸟嘌呤DNA甲基转移酶（MGMT）、n -甲基嘌呤DNA糖基化酶（MPG）和Rad51是介导胶质母细胞瘤对替莫唑胺耐药的DNA损伤修复蛋白。在这项工作中，我们试图评估内质网应激诱导药物是否能够下调DNA损伤修复蛋白，并成为与替莫唑胺联合的候选药物。采用MTT试验评价各处理的细胞毒性。western blot和免疫荧光法检测蛋白表达。采用2种原位胶质母细胞瘤裸鼠模型进行体内研究，以评价治疗的疗效。所有统计检验均为双侧检验。内质网应激诱导药物治疗胶质母细胞瘤细胞导致MGMT、MPG和Rad51下调。通过药物治疗抑制内质网应激导致MGMT、MPG和Rad51蛋白水平的恢复。此外，在体外实验中，盐霉素（一种内质网应激诱导药物）和替莫唑胺联合治疗胶质母细胞瘤细胞可增强DNA损伤，并具有协同抗肿瘤作用。重要的是，盐霉素/替莫唑胺治疗在2个侵袭性颅内瘤模型中具有显著的抗胶质瘤作用。这些发现为替莫唑胺联合内质网应激诱导药物作为胶质母细胞瘤的替代治疗策略提供了强有力的理论依据。
Endoplasmic reticulum (ER) stress results from protein misfolding imbalance and has been postulated as a therapeutic strategy. ER stress activates the unfolded protein response which leads to a complex cellular response, including the upregulation of aberrant protein degradation in the ER, with the goal of resolving that stress. O-6-methylguanine DNA methyltransferase (MGMT), N-methylpurine DNA glycosylase (MPG), and Rad51 are DNA damage repair proteins that mediate resistance to temozolomide in glioblastoma. In this work we sought to evaluate whether ER stress-inducing drugs were able to downmodulate DNA damage repair proteins and become candidates to combine with temozolomide.MTT assays were performed to evaluate the cytotoxicity of the treatments. The expression of proteins was evaluated using western blot and immunofluorescence. In vivo studies were performed using 2 orthotopic glioblastoma models in nude mice to evaluate the efficacy of the treatments. All statistical tests were 2-sided.Treatment of glioblastoma cells with ER stress-inducing drugs leads to downregulation of MGMT, MPG, and Rad51. Inhibition of ER stress through pharmacological treatment resulted in rescue of MGMT, MPG, and Rad51 protein levels. Moreover, treatment of glioblastoma cells with salinomycin, an ER stress-inducing drug, and temozolomide resulted in enhanced DNA damage and a synergistic antitumor effect in vitro. Of importance, treatment with salinomycin/temozolomide resulted in a significant antiglioma effect in 2 aggressive orthotopic intracranial brain tumor models.These findings provide a strong rationale for combining temozolomide with ER stress-inducing drugs as an alternative therapeutic strategy for glioblastoma.