Tumor cycling hypoxia induces chemoresistance in glioblastoma multiforme by upregulating the expression and function of ABCB1
Tumor cycling hypoxia induces chemoresistance in glioblastoma multiforme by upregulating the expression and function of ABCB1
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DOI：
10.1093/neuonc/nos195
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发表时间：
2012-10-01
期刊：
影响因子：
15.9
通讯作者：
Hsieh, Chia-Hung
中科院分区：
文献类型：
--
作者：
Chou, Chii-Wen;Wang, Chi-Chung;Hsieh, Chia-Hung
肿瘤循环缺氧现在是动物和人类实体瘤中公认的现象。然而，肿瘤循环缺氧如何影响化疗尚不清楚。在本研究中，我们探讨了循环缺氧对肿瘤微环境介导的化疗耐药的影响及其机制。 Hoechst 33342 染色和缺氧诱导因子 1 (HIF-1) 激活标记以及免疫荧光成像和荧光激活细胞分选用于从人胶质母细胞瘤异种移植物中分离缺氧肿瘤亚群。分别使用蛋白质印迹分析、药物累积和外排测定以及 MTT 测定测定来自人胶质母细胞瘤异种移植物或体外循环低氧应激处理的胶质母细胞瘤细胞的肿瘤细胞中的 ABCB1 表达、P-糖蛋白功能和化疗敏感性。在循环缺氧条件下，胶质母细胞瘤细胞的 ABCB1 表达和 P-糖蛋白功能上调，同时对阿霉素和 BCNU 的反应降低。然而，ABCB1 敲除抑制了这些作用。此外，胶质母细胞瘤中 ABCB1、HIF-1 激活和 Hoechst 3342 的免疫荧光成像和流式细胞术分析显示，ABCB1 高度局部表达，主要在实体瘤微环境中具有 HIF-1 激活和血液灌注的潜在循环缺氧区域。与慢性缺氧和常氧细胞相比，来自胶质母细胞瘤异种移植物的循环缺氧肿瘤细胞表现出更高的 ABCB1 表达、P-糖蛋白功能和化疗耐药性。接受 YC-1（一种 HIF-1 抑制剂）的荷瘤小鼠在 BCNU 化疗中表现出抑制肿瘤微环境诱导的 ABCB1 诱导并提高生存率。循环缺氧通过 HIF-1 依赖性诱导 ABCB1 在肿瘤微环境介导的化疗耐药中发挥着至关重要的作用。化疗前和化疗同时阻断 HIF-1 可以抑制循环缺氧引起的化疗耐药。
Tumor cycling hypoxia is now a well-recognized phenomenon in animal and human solid tumors. However, how tumor cycling hypoxia impacts chemotherapy is unclear. In the present study, we explored the impact and the mechanism of cycling hypoxia on tumor microenvironment-mediated chemoresistance. Hoechst 33342 staining and hypoxia-inducible factor1 (HIF-1) activation labeling together with immunofluorescence imaging and fluorescence-activated cell sorting were used to isolate hypoxic tumor subpopulations from human glioblastoma xenografts. ABCB1 expression, P-glycoprotein function, and chemosensitivity in tumor cells derived from human glioblastoma xenografts or in vitro cycling hypoxic stress-treated glioblastoma cells were determined using Western blot analysis, drug accumulation and efflux assays, and MTT assay, respectively. ABCB1 expression and P-glycoprotein function were upregulated under cycling hypoxia in glioblastoma cells concomitant with decreased responses to doxorubicin and BCNU. However, ABCB1 knockdown inhibited these effects. Moreover, immunofluorescence imaging and flow cytometric analysis for ABCB1, HIF-1 activation, and Hoechst 3342 in glioblastoma revealed highly localized ABCB1 expression predominantly in potentially cycling hypoxic areas with HIF-1 activation and blood perfusion in the solid tumor microenvironment. The cycling hypoxic tumor cells derived from glioblastoma xenografts exhibited higher ABCB1 expression, P-glycoprotein function, and chemoresistance, compared with chronic hypoxic and normoxic cells. Tumor-bearing mice that received YC-1, an HIF-1 inhibitor, exhibited suppressed tumor microenvironment-induced ABCB1 induction and enhanced survival rate in BCNU chemotherapy. Cycling hypoxia plays a vital role in tumor microenvironment-mediated chemoresistance through the HIF-1dependent induction of ABCB1. HIF-1 blockade before and concurrent with chemotherapy could suppress cycling hypoxia-induced chemoresistance.