Basic FGF augments hypoxia induced HIF-1-alpha expression and VEGF release in T47D breast cancer cells
Basic FGF augments hypoxia induced HIF-1-alpha expression and VEGF release in T47D breast cancer cells
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碱性 FGF 增强 T47D 乳腺癌细胞缺氧诱导的 HIF-1-α 表达和 VEGF 释放
DOI：
10.1080/00313020701444549
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发表时间：
2007-08-01
期刊：
影响因子：
4.5
通讯作者：
Fang, Wei-Gang
中科院分区：
文献类型：
--
作者：
Shi, Yong-Hong;Bingle, Lynne;Fang, Wei-Gang
目的：缺氧诱导因子1（HIF-1）和碱性成纤维细胞生长因子（bFGF）在肿瘤血管生成中起重要作用。本研究旨在阐明这两种介质在诱导乳腺癌血管内皮细胞生长因子（VEGF）释放中的协同作用，并探讨其可能的机制。方法：采用酶联免疫吸附试验（ELISA）检测乳腺癌细胞株（T47 D）VEGF的释放。Western blotting检测HIF-1和ERK的表达。结果：缺氧诱导了HIF-1 α蛋白的表达、HIF-1的转录活性和VEGF的释放。bFGF进一步增强了这些缺氧诱导。如通过应用PI 3激酶抑制剂（LY 294002）或突变体构建体转染所证明的，这些过程需要PI 3 K途径。相反，MEK 1抑制剂PD 98059对HIF-1或VEGF释放的激活均无影响，这与我们发现ERK 1/2不被缺氧激活一致。在缺氧条件下，bFGF激活MEK 1/ERK通路。PD 98059可阻断ERK 1/2的激活，抑制bFGF诱导的HIF-1的反式活性，但不影响HIF-1 α的蛋白表达和VEGF的释放。结论：bFGF主要通过PI 3 K途径促进缺氧诱导的VEGF释放，部分依赖于HIF-1的活性。阐明这一机制可能为肿瘤治疗中的抗血管生成提供新的靶点。
Aim: Both hypoxia inducible factor 1 (HIF-1) and basic fibroblast growth factor (bFGF) play important roles in tumour angiogenesis. This study was designed to clarify the cooperative effect of these two mediators in induction of vascular endothelial cell growth factor (VEGF) release from breast cancer and probe possible mechanisms involved.Methods: Release of VEGF from a breast cancer cell line (T47D) was quantitated by enzyme linked immunosorbent assay (ELISA). Expression of HIF-1 and ERK was assayed using Western blotting. Transient transfection and dual luciferase reporter assay were used to study HIF-1 transactivity.Results: The data showed that hypoxia induced the expression of HIF-1 alpha protein, the transactivity of HIF-1 and the release of VEGF. bFGF further augmented these hypoxic inductions. The PI3K pathway was required for these processes as demonstrated by application of PI3Kinase inhibitor (LY294002) or mutant construct transfections. In contrast, the MEK1 inhibitor PD98059 showed no effect on either activation of HIF-1 or VEGF release, which is in agreement with our finding that ERK1/2 was not activated by hypoxia. Under hypoxic conditions, bFGF activated the MEK1/ERK pathway. PD98059 blocked the activation of ERK1/2 and suppressed bFGF-induced HIF-1 transactivity, yet the protein expression of HIF-1 alpha or VEGF release was not affected by PD98059.Conclusion: bFGF augments hypoxia induced VEGF release mainly through the PI3K pathway and partly depending on HIF-1 activity. Elucidation of this mechanism may provide a new target for anti-angiogenesis in cancer therapy.