Optical Imaging of Tumor Hypoxia and Evaluation of Efficacy of a Hypoxia-Targeting Drug in Living Animals
Optical Imaging of Tumor Hypoxia and Evaluation of Efficacy of a Hypoxia-Targeting Drug in Living Animals
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DOI：
10.1162/15353500200505112
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发表时间：
2005-07
影响因子：
2.8
通讯作者：
H. Harada;S. Kizaka-Kondoh;M. Hiraoka
中科院分区：
文献类型：
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作者：
H. Harada;S. Kizaka-Kondoh;M. Hiraoka
含有更多缺氧区的实体瘤通过增加编码血管生成和转移因子的基因的表达而显示出更恶性的表型。低氧诱导因子-1(HIF-1)是这类基因的主要转录激活剂，因此，成像和靶向HIF-1活性的低氧肿瘤细胞在癌症治疗中具有重要意义。在本研究中，利用荧光素酶报告基因，在人工HIF-1依赖启动子5HRE的调控下，通过光学体内成像系统监测HIF-1的活性。为了监测肿瘤的缺氧，我们分离了一个稳定的报告基因转染体HeLa/5HRE-Luc，它能在低氧应激下表达100多倍的荧光素酶，并观察到其异种移植瘤的生物发光。异种移植细胞的免疫组织化学分析证实，表达荧光素酶的细胞是低氧的。使用这种光学成像系统评估低氧靶向前药TOP3的疗效显示，TOP3治疗显著减少了低氧细胞。TOP3处理的异种移植瘤的免疫组织化学分析证实，低氧细胞发生了凋亡，并在TOP3处理后被移除。这些结果表明，使用5HRE-荧光素酶报告构建的模型系统提供了实体肿瘤的定性信息(低氧状态)，并使人们能够方便地评估癌症治疗对恶性实体瘤低氧的疗效。
Solid tumors containing more hypoxic regions show a more malignant phenotype by increasing the expression of genes encoding angiogenic and metastatic factors. Hypoxia-inducible factor-1 (HIF-1) is a master transcriptional activator of such genes, and thus, imaging and targeting hypoxic tumor cells where HIF-1 is active are important in cancer therapy. In the present study, HIF-1 activity was monitored via an optical in vivo imaging system by using a luciferase reporter gene under the regulation of an artificial HIF-1-dependent promoter, 5HRE. To monitor tumor hypoxia, we isolated a stable reporter-transfectant, HeLa/5HRE-Luc, which expressed more than 100-fold luciferase in response to hypoxic stress, and observed bioluminescence from its xenografts. Immunohistochemical analysis of the xenografts with a hypoxia marker, pimonidazole, confirmed that the luciferase-expressing cells were hypoxic. Evaluation of the efficacy of a hypoxia-targeting prodrug, TOP3, using this optical imaging system revealed that hypoxic cells were significantly diminished by TOP3 treatment. Immunohistochemical analysis of the TOP3-treated xenografts confirmed that hypoxic cells underwent apoptosis and were removed after TOP3 treatment. These results demonstrate that this model system using the 5HRE-luciferase reporter construct provides qualitative information (hypoxic status) of solid tumors and enables one to conveniently evaluate the efficacy of cancer therapy on hypoxia in malignant solid tumors.