Hypoxia inducible factor-1 mediates upregulation of urokinase-type plasminogen activator receptor gene transcription during hypoxia in cervical cancer cells
Hypoxia inducible factor-1 mediates upregulation of urokinase-type plasminogen activator receptor gene transcription during hypoxia in cervical cancer cells
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DOI：
10.3892/or.2015.4449
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发表时间：
2016-02-01
期刊：
影响因子：
4.2
通讯作者：
Isaka, Keiichi
中科院分区：
文献类型：
--
作者：
Nishi, Hirotaka;Sasaki, Toru;Isaka, Keiichi
缺氧发生在宫颈癌的发展过程中，并被认为与其侵袭有关。在多种癌症中，缺氧介导肿瘤细胞具有更强的侵袭性。尿激酶型纤溶酶原激活物受体（uPAR）介导细胞的侵袭，被认为是由缺氧诱导的。我们试图确定子宫颈癌缺氧过程中uPAR表达的调节因子。我们通过侵袭实验表明，宫颈癌细胞系CaSki和CA在缺氧条件（1%O-2）下比在常氧条件（20%O-2）下更具侵袭性。Western blot分析显示，缺氧可增强内源性缺氧诱导因子（HIF）-1 α和uPAR蛋白的表达。实时定量RT-PCR结果显示，缺氧可上调uPAR mRNA水平。通过荧光素酶测定，由缺氧诱导的HIF-1 α的过表达激活了uPAR启动子的转录活性。使用电泳迁移率变动分析，HIF-1蛋白结合uPAR启动子上的推定HIF-1响应元件，并且另外的荧光素酶测定显示这对于HIF-1的uPAR反式激活是必需的。HIF-1过表达增强了内源性uPAR表达，而针对HIF-1 α的siRNA的引入减少了缺氧期间uPAR的表达。这些结果表明，宫颈癌细胞中低氧上调uPAR是通过HIF-1介导的。在宫颈癌组织中，我们也证明了uPAR蛋白表达检测宫颈癌，但在正常宫颈或宫颈上皮内瘤变（CIN）的免疫组织病理学染色。我们的研究结果提供了证据表明，HIF-1的调节uPAR表达的宫颈癌在缺氧时的侵袭机制。
Hypoxia occurs during development of cervical cancer and is considered to correlate with its invasion. Hypoxia mediates tumor cells to have more invasive property in a variety of cancers. Urokinase plasminogen activator receptor (uPAR) which mediates invasion is considered to be induced by hypoxia. We sought to determine the regulators of uPAR expression during hypoxia in cervical cancer. We showed that cervical cancer cell lines, CaSki and CA, were more invasive under hypoxic condition (1% O-2) than under normoxic condition (20% O-2) by invasion assays. Using western blot analysis, hypoxia enhanced the endogenous hypoxia-inducible factor (HIF)-1 alpha and uPAR protein expression. uPAR mRNA level was also upregulated by hypoxia using real-time RT-PCR. Overexpression of HIF-1 alpha which is induced by hypoxia activated the transcriptional activity of the uPAR promoter by luciferase assays. HIF-1 protein bound the putative HIF-1 response element on the uPAR promoter using electrophoretic mobility shift analysis, and additional luciferase assays show that this is essential for uPAR transactivation by HIF-1. HIF-1 overexpression enhanced the endogenous uPAR expression and introduction of siRNA for HIF-1 alpha diminishes uPAR expression during hypoxia. These results indicate the upregulation of uPAR by hypoxia in cervical cancer cells is mediated through HIF-1. In cervical cancer tissues, we also demonstrated that uPAR protein expression was detected in cervical cancer but not in normal cervix or cervical intraepithelial neoplasia (CIN) by immunohistopathological staining. Our results provide evidence that regulation of uPAR expression by HIF-1 represents a mechanism for cervical cancer invasion during hypoxia.