The Involvement of Mitochondrial Membrane Potential in Cross-Resistance Between Radiation and Docetaxel
The Involvement of Mitochondrial Membrane Potential in Cross-Resistance Between Radiation and Docetaxel
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DOI：
10.1016/j.ijrobp.2016.07.002
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发表时间：
2016-11-01
影响因子：
7
通讯作者：
Fukumoto, Manabu
中科院分区：
文献类型：
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作者：
Kuwahara, Yoshikazu;Roudkenar, Mehryar Habibi;Fukumoto, Manabu
目的：为了理解癌细胞辐射抗性的分子机制，建立了在暴露于2戈伊/天X射线超过30天期间继续增殖的临床相关的辐射抗性（CRR）细胞。一项用于抗癌药物筛选的改良高密度存活试验显示，CRR细胞对抗微管剂多西他赛（DTX）具有耐药性。参与的活性氧（ROS）frommitochondrial（mtROS）的交叉抗性X射线和DTX.Methods和材料：抗癌药物的敏感性测定由一个修改的高密度细胞存活或水溶性四唑盐测定。通过MitoSOX红染色测定DTX诱导的mtROS产生。JC-1染色用于可视化线粒体膜电位。DTX诱导的DNA双链断裂通过γ-H2 AX染色来确定。为了获得线粒体DNA缺失（rho（0））的细胞，将细胞在含有溴化乙锭的培养基中培养3至4周。DTX诱导亲本细胞DNA双链断裂。CRR细胞的线粒体膜电位低于亲代细胞。线粒体DNA的缺失诱导了亲本细胞的DTX抗性。二甲基亚砜处理也诱导了亲代细胞的DTX抗性。结论：CRR细胞中观察到的线粒体功能障碍有助于X射线和DTX交叉抗性。CRR细胞中氧化磷酸化的激活可能代表克服放射抗性癌症的有效方法。一般来说，β-微管蛋白或多药外排泵的过度表达被认为与DTX抗性有关。在本研究中，我们通过研究CRR细胞发现了另一种DTX抗性机制。(C)2016 Elsevier Inc. All rights reserved.
Purpose: To understand the molecular mechanisms underlying cancer cell radioresistance, clinically relevant radioresistant (CRR) cells that continue to proliferate during exposure to 2 Gy/day X-rays for more than 30 days were established. A modified high-density survival assay for anticancer drug screening revealed that CRR cells were resistant to an antimicrotubule agent, docetaxel (DTX). The involvement of reactive oxygen species (ROS) frommitochondria (mtROS) in the cross-resistance to X-rays and DTX was studied.Methods and Materials: Sensitivity to anticancer agents was determined by a modified high-density cell survival or water-soluble tetrazolium salt assay. DTX-induced mtROS generation was determined by MitoSOX red staining. JC-1 staining was used to visualize mitochondrial membrane potential. DTX-induced DNA double-strand breaks were determined by gamma-H2AX staining. To obtain mitochondrial DNA-lacking (rho(0)) cells, the cells were cultured for 3 to 4 weeks in medium containing ethidium bromide.Results: Treatment with DTX increased mtROS in parental cells but not in CRR cells. DTX induced DNA double-strand breaks in parental cells. The mitochondrial membrane potential of CRR cells was lower in CRR cells than in parental cells. Depletion of mtDNA induced DTX resistance in parental cells. Treatment with dimethyl sulfoxide also induced DTX resistance in parental cells.Conclusions: The mitochondrial dysfunction observed in CRR cells contributes to X-ray and DTX cross-resistance. The activation of oxidative phosphorylation in CRR cells may represent an effective approach to overcome radioresistant cancers. In general, the overexpression of beta-tubulin or multidrug efflux pumps is thought to be involved in DTX resistance. In the present study, we discovered another DTX resistant mechanism by investigating CRR cells. (C) 2016 Elsevier Inc. All rights reserved.