von Marschall Zofia, Scholz Arne, Cramer Thorsten, Schäfer Georgia, Schirner Michael, Oberg Kjell, Wiedenmann Bertram, Höcker Michael, Rosewicz Stefan
Department of Hepatology, Gastroenterology, Endocrinology and Metabolism, Charité, Campus Virchow-Klinikum, Humboldt-University, Berlin, Germany.
J Natl Cancer Inst. 2003 Mar 19;95(6):437-48. doi: 10.1093/jnci/95.6.437.
Interferon alpha (IFN-alpha) has antiangiogenic activity, although the underlying mechanism of action is unclear. Because human neuroendocrine (NE) tumors are highly vascularized and sensitive to IFN-alpha, we investigated whether the therapeutic effects of IFN-alpha result from an inhibition of angiogenesis mediated by a decrease in vascular endothelial growth factor (VEGF) gene expression.
VEGF gene and protein expression was analyzed in NE tumors by immunohistochemistry and in NE tumor cell lines by quantitative competitive reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). VEGF promoter-reporter gene constructs containing various deletions or mutations and gel shift assays were used to identify minimal promoter requirements and potential transcription factors. A xenograft nude mouse model (five mice per group) was used to determine the effect of IFN-alpha on tumor growth (NE Bon cells and pancreatic Capan-1 cells) and microvessel density. Liver metastases from eight patients with NE tumors were analyzed for microvessel density, VEGF mRNA content, and VEGF plasma levels before and after initiation of IFN-alpha therapy.
NE tumors and cell lines expressed VEGF mRNA and secreted VEGF protein. In vitro, IFN-alpha decreased transcription of VEGF gene expression through an Sp1- and/or Sp3-dependent inhibition of VEGF promoter activity. Compared with vehicle treatment in mice, IFN-alpha inhibited tumor growth by 36% and reduced microvessel density from 56 (95% confidence interval [CI] = 49 to 69) to 37 per x400 Field (95% CI = 32 to 41, P =.015). Patients with NE tumors had lower VEGF plasma levels and reduced VEGF mRNA levels and microvessel density in liver metastasis biopsy material after IFN-alpha treatment.
IFN-alpha confers its antitumor activity, at least in part, by its antiangiogenic activity, which results from Sp1- and/or Sp3-mediated inhibition of VEGF gene transcription.
干扰素α（IFN-α）具有抗血管生成活性，但其潜在作用机制尚不清楚。由于人类神经内分泌（NE）肿瘤血管高度丰富且对IFN-α敏感，我们研究了IFN-α的治疗效果是否源于血管内皮生长因子（VEGF）基因表达降低介导的血管生成抑制。
通过免疫组织化学分析NE肿瘤中的VEGF基因和蛋白表达，并通过定量竞争逆转录聚合酶链反应（RT-PCR）和酶联免疫吸附测定（ELISA）分析NE肿瘤细胞系中的VEGF基因和蛋白表达。使用含有各种缺失或突变的VEGF启动子-报告基因构建体和凝胶迁移试验来确定最小启动子要求和潜在转录因子。使用异种移植裸鼠模型（每组五只小鼠）来确定IFN-α对肿瘤生长（NE Bon细胞和胰腺Capan-1细胞）和微血管密度的影响。分析了8例NE肿瘤患者肝转移灶在IFN-α治疗前后的微血管密度、VEGF mRNA含量和VEGF血浆水平。
NE肿瘤和细胞系表达VEGF mRNA并分泌VEGF蛋白。在体外，IFN-α通过对VEGF启动子活性的Sp1和/或Sp3依赖性抑制降低VEGF基因表达的转录。与小鼠中的载体处理相比，IFN-α抑制肿瘤生长36%，并将微血管密度从每400视野56（95%置信区间[CI]=49至69）降低至37（95%CI=32至41，P=0.015）。NE肿瘤患者在IFN-α治疗后，肝转移活检材料中的VEGF血浆水平降低，VEGF mRNA水平和微血管密度降低。
IFN-α至少部分通过其抗血管生成活性赋予其抗肿瘤活性，这是由Sp1和/或Sp3介导的VEGF基因转录抑制所致。
