Cycling hypoxia induces chemoresistance through the activation of reactive oxygen species-mediated B-cell lymphoma extra-long pathway in glioblastoma multiforme.
Cycling hypoxia induces chemoresistance through the activation of reactive oxygen species-mediated B-cell lymphoma extra-long pathway in glioblastoma multiforme.
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DOI：
10.1186/s12967-015-0758-8
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发表时间：
2015-12-28
影响因子：
7.4
通讯作者：
Hsieh CH
中科院分区：
文献类型：
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作者：
Chen WL;Wang CC;Lin YJ;Wu CP;Hsieh CH
循环缺氧在动物和人类实体肿瘤中是一种公认的现象。它通过抗凋亡作用有助于抵抗细胞毒性治疗。然而，循环缺氧介导的抗凋亡机制尚不清楚。通过体外ROS分析、报告基因分析、western blotting分析、实时荧光定量PCR、caspase-3活性测定、体外缺氧胁迫处理的人胶质瘤细胞或肿瘤缺氧细胞中活性氧（ROS）的产生、缺氧诱导因子-1α (HIF-1α)和核因子-κB （NF-κB）信号通路的激活、b细胞淋巴瘤超长（Bcl-xL）表达、caspase激活和凋亡的变化。膜联蛋白V染色法。利用Tempol（一种膜透性自由基清除剂）、Bcl-xL敲低和HIF-1α和NF-κB特异性抑制剂，在体外和体内探讨了循环缺氧介导的替莫唑胺（TMZ）耐药机制，并确定了潜在的治疗靶点。在恶性胶质瘤细胞循环缺氧条件下，Bcl-xL的表达和抗凋亡作用上调，并通过ros介导的HIF-1α和NF-κB活化降低对TMZ的应答。Tempol、YC-1 （HIF-1抑制剂）和Bay 11-7082 （NF-κB抑制剂）在体外和体内均抑制循环缺氧介导的Bcl-xL诱导。Bcl-xL基因敲低和Tempol处理可抑制循环缺氧诱导的化疗耐药。此外，Tempol治疗脑内胶质母细胞瘤小鼠联合TMZ化疗可协同抑制肿瘤生长，提高生存率。通过ros介导的HIF-1α和NF-κB活化循环缺氧诱导的Bcl-xL表达在肿瘤微环境促进的胶质母细胞瘤抗凋亡和化疗耐药中起重要作用。因此，ROS阻断可能是治疗肿瘤微环境诱导的化疗耐药的一种有吸引力的治疗策略。
Cycling hypoxia is a well-recognized phenomenon within animal and human solid tumors. It contributes to the resistance to cytotoxic therapies through anti-apoptotic effects. However, the mechanism underlying cycling hypoxia-mediated anti-apoptosis remains unclear. Reactive oxygen species (ROS) production, activation of the hypoxia-inducible factor-1 alpha (HIF-1α) and nuclear factor-κB (NF-κB) signaling pathways, B-cell lymphoma extra-long (Bcl-xL) expression, caspase activation, and apoptosis in in vitro hypoxic stress-treated glioblastoma cells or tumor hypoxic cells derived from human glioblastoma xenografts were determined by in vitro ROS analysis, reporter assay, western blotting analysis, quantitative real-time PCR, caspase-3 activity assay, and annexin V staining assay, respectively. Tempol, a membrane-permeable radical scavenger, Bcl-xL knockdown, and specific inhibitors of HIF-1α and NF-κB were utilized to explore the mechanisms of cycling hypoxia-mediated resistance to temozolomide (TMZ) in vitro and in vivo and to identify potential therapeutic targets. Bcl-xL expression and anti-apoptotic effects were upregulated under cycling hypoxia in glioblastoma cells concomitantly with decreased responses to TMZ through ROS-mediated HIF-1α and NF-κB activation. Tempol, YC-1 (HIF-1 inhibitor), and Bay 11-7082 (NF-κB inhibitor) suppressed the cycling hypoxia-mediated Bcl-xL induction in vitro and in vivo. Bcl-xL knockdown and Tempol treatment inhibited cycling hypoxia-induced chemoresistance. Moreover, Tempol treatment of intracerebral glioblastoma-bearing mice combined with TMZ chemotherapy synergistically suppressed tumor growth and increased survival rate. Cycling hypoxia-induced Bcl-xL expression via ROS-mediated HIF-1α and NF-κB activation plays an important role in the tumor microenvironment-promoted anti-apoptosis and chemoresistance in glioblastoma. Thus, ROS blockage may be an attractive therapeutic strategy for tumor microenvironment-induced chemoresistance.