Hypoxia regulates choline kinase expression through hypoxia-inducible factor-lot signaling in a human prostate cancer model
Hypoxia regulates choline kinase expression through hypoxia-inducible factor-lot signaling in a human prostate cancer model
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DOI：
10.1158/0008-5472.can-07-2678
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发表时间：
2008-01-01
期刊：
影响因子：
11.2
通讯作者：
Bhujwalla, Zaver M.
中科院分区：
文献类型：
--
作者：
Glunde, Kristine;Shah, Tariq;Bhujwalla, Zaver M.
肿瘤光谱图像中总胆碱 (tCho) 信号的强度在空间上存在异质性。同样异质的生理肿瘤微环境可能导致这种异质性。因此，我们研究了人类前列腺癌模式中缺氧、胆碱代谢物和胆碱激酶 (Chk) 之间的关系。人类 PC-3 前列腺癌细胞经过改造，可在缺氧条件下表达增强型绿色荧光蛋白 (EGFP)。使用 H-1 磁共振波谱 (MRS) 和 MRS 成像 (MRSI) 结合 EGFP 荧光显微镜和成像对这些 PC-3-5HRE-EGFP 细胞进行培养和移植到小鼠体内的肿瘤进行表征。在 MRSI 和光学成像联合研究中，缺氧 EGFP 荧光肿瘤区域与高 WHO 区域共定位。 PC-3 细胞暴露于缺氧后，细胞磷酸胆碱 (PC) 和 Who 浓度以及 Chk 表达水平显着增加。克隆了位于人 chk-alpha 基因翻译起始位点 5' 的推定启动子区域，并生成了基于荧光素酶 (Luc) 的报告载体构建体。 Luc 报告基因检测提供的证据表明，该推定的 chk-alpha 启动子区域内的一些推定的缺氧反应元件 (HRE) 在体外发挥作用。使用抗缺氧诱导因子 (HIF)-1 α 的抗体进行的染色质免疫沉淀测定表明，HIF-1 可以直接结合缺氧 PC-3-5HM-EGFP 细胞中内源 chk-α 启动子的该区域。这些数据表明，HIF-1 激活假定的 chk-alpha 启动子区域内的 HRE 可以增加缺氧环境中 Chk-alpha 的表达，从而增加这些环境中的细胞 PC 和 Who 水平。
The intensity of the total choline (tCho) signal in spectroscopic images of tumors is spatially heterogeneous. The likewise heterogeneous physiologic tumor microenvironment may contribute to this heterogeneity. We therefore investigated the relationship between hypoxia, choline metabolites, and choline kinase (Chk) in a human prostate cancer mode. Human PC-3 prostate cancer cells were engineered to express enhanced green fluorescent protein (EGFP) under hypoxic conditions. These PC-3-5HRE-EGFP cells were characterized in culture and as tumors transplanted in mice using H-1 magnetic resonance spectroscopy (MRS) and MRS imaging (MRSI) combined with EGFP fluorescence microscopy and imaging. Hypoxic EGFP-fluorescing tumor regions colocalized with regions of high Who in combined MRSI and optical imaging studies. Cellular phosphocholine (PC) and Who concentrations as well as Chk expression levels significantly increased following exposure of PC-3 cells to hypoxia. A putative promoter region located 5' of the translation start site of the human chk-alpha gene was cloned and luciferase (Luc)-based reporter vector constructs were generated. Luc reporter assays provided evidence that some of the putative hypoxia response elements (HRE) within this putative chk-alpha promoter region functioned in vitro. Chromatin immunoprecipitation assays using an antibody against hypoxia-inducible factor (HIF)-1 alpha showed that HIF-1 can directly bind this region of the endogenous chk-alpha promoter in hypoxic PC-3-5HM-EGFP cells. These data suggest that HIF-1 activation of HREs within the putative chk-alpha promoter region can increase Chk-alpha expression within hypoxic environments, consequently increasing cellular PC and Who levels within these environments.