The antiepidermal growth factor receptor monoclonal antibody cetuximab/C225 reduces hypoxia-inducible factor-1 alpha, leading to transcriptional inhibition of vascular endothelial growth factor expression
The antiepidermal growth factor receptor monoclonal antibody cetuximab/C225 reduces hypoxia-inducible factor-1 alpha, leading to transcriptional inhibition of vascular endothelial growth factor expression
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DOI：
10.1038/sj.onc.1208625
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发表时间：
2005-06-01
期刊：
影响因子：
8
通讯作者：
Fan, Z
中科院分区：
文献类型：
--
作者：
Luwor, RB;Lu, Y;Fan, Z
我们以前已经表明，抗表皮生长因子受体单克隆抗体西妥昔单抗（C225;爱必妥），这是最近批准的转移性结直肠癌的治疗，具有抗血管生成的特性，抑制血管内皮生长因子（VEGF）分泌的文化和动物模型。在这里，我们进一步的研究表明，西妥昔单抗降低缺氧诱导因子-1 α（HIF-1 α），VEGF表达的转录调节因子，在A431表皮样癌细胞在常氧和缺氧培养条件下的细胞水平。在A431细胞中组成型活性Ras的表达使细胞对西妥昔单抗介导的HIF-1 α水平降低产生抗性。在10号染色体上缺失天然存在的磷酸酶和张力蛋白同源物突变或缺失的细胞系也对西妥昔单抗介导的HIF-1 α水平降低具有抗性。用LY 294002药理学抑制磷脂酰肌醇3-激酶降低常氧和缺氧A431细胞中的HIF-1 α水平，而用PD 98059抑制促分裂原活化蛋白激酶激酶仅降低常氧A431细胞中的HIF-1 α水平。此外，在蛋白酶体抑制剂lactacystin存在下，西妥昔单抗降低了HIF-1 α的细胞水平，表明西妥昔单抗主要作用于蛋白质合成水平。西妥昔单抗治疗后HIF-1 α的减少伴随着VEGF表达的转录抑制，这通过用含有VEGF缺氧反应元件的载体转染的A431细胞中的荧光素酶测定来测量。综上所述，我们的结果表明，先前证实的西妥昔单抗对VEGF的抑制作用发生在转录水平上，以响应HIF-1 α水平的降低，并证明进一步测试将联合收割机西妥昔单抗与抑制VEGF或VEGF受体功能的方法相结合的治疗策略是合理的。
We have previously shown that the antiepidermal growth factor receptor monoclonal antibody cetuximab (C225; Erbitux), which was recently approved for the treatment of metastatic colorectal cancer, has antiangiogenic properties, inhibiting vascular endothelial growth factor (VEGF) secretion in culture and in animal models. Here, we have furthered the study by demonstrating that cetuximab reduces cellular levels of hypoxia-inducible factor-1 alpha (HIF-1 alpha), a transcriptional regulator of VEGF expression, in A431 epidermoid carcinoma cells under both normoxic and hypoxic culture conditions. Expression of a constitutively active Ras in A431 cells rendered cellular resistance to the cetuximab-mediated reduction of the HIF-1 alpha level. Cell lines with naturally occurring phosphatase and tensin homologue deleted on chromosome 10 mutations or deletions were also resistant to cetuximab-mediated reduction of the HIF-1 alpha level. Pharmacologic inhibition of phosphatidylinositol 3-kinase with LY294002 reduced the HIF-1 alpha level in both normoxic and hypoxic A431 cells, whereas inhibition of the mitogen- activated protein kinase kinase by PD98059 reduced the level of HIF-1 alpha only in normoxic A431 cells. In addition, cetuximab reduced the cellular level of HIF-1 alpha in the presence of a proteasome inhibitor, lactacystin, indicating that cetuximab acts mainly at the level of protein synthesis. The reduction of HIF-1 alpha in response to cetuximab treatment was accompanied by transcriptional inhibition of VEGF expression, measured by a luciferase assay in A431 cells transfected with a vector containing the VEGF hypoxia response element. Taken together, our results indicate that the previously demonstrated inhibition of VEGF by cetuximab occurs at the level of transcription in response to a reduced level of HIF-1 alpha and justify further testing of therapeutic strategies that combine cetuximab with approaches inhibiting the function of VEGF or the VEGF receptor.