BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.
BACKGROUND: 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. METHODS: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. RESULTS: 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. CONCLUSION: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.
Authors: Jonathan J Duplisea; Sharada Mokkapati; Devin Plote; Kimberly S Schluns; David J McConkey; Seppo Yla-Herttuala; Nigel R Parker; Colin P Dinney Journal: World J Urol Date: 2018-11-11 Impact factor: 4.226
Authors: Hong Zheng; Christine Wasylyk; Abdelkader Ayadi; Joseph Abecassis; Jack A Schalken; Hermann Rogatsch; Nicolas Wernert; Sauveur-Michel Maira; Marie-Christine Multon; Bohdan Wasylyk Journal: Genes Dev Date: 2003-09-15 Impact factor: 11.361
Authors: Robert J Motzer; Gary Hudes; George Wilding; Lawrence H Schwartz; Subramanian Hariharan; Susan Kempin; Rana Fayyad; Robert A Figlin Journal: Clin Genitourin Cancer Date: 2009-01 Impact factor: 2.872