BACKGROUND: Breast tumors contain high numbers of infiltrating macrophages. The role and function of these cells within the tumor remain unclear, but a number of studies have found an association between poor prognosis and macrophage content in human breast cancer. Both hypoxia and TGFbeta-1 have been shown to regulate VEGF in other cell types. We hypothesized that breast tumor-associated macrophages produce VEGF and that macrophage production of this factor is regulated by both hypoxia and TGFbeta-1. METHODS: Paraffin-embedded breast tumor sections were stained immunohistochemically with anti-VEGF, anti-CD68, and anti-cytokeratin. Monocytes were matured for 3 days in 20% autologous plasma and activated with 1000 U/mL interferon-gamma for 24 hours. Supernatants were assayed for VEGF protein by ELISA. Total RNA was isolated from cells and reverse transcribed to cDNA, which was used as a template in PCR reactions for VEGF and beta-actin. RESULTS: Both tumor cells and tumor macrophages produce VEGF in human breast tumors. Hypoxia increases VEGF protein and mRNA levels in monocyte-derived macrophages, whereas TGFbeta-1 increases VEGF protein but not mRNA under hypoxic growth conditions. CONCLUSIONS: Breast tumor-associated macrophages may contribute to the angiogenic activity of human breast tumors by producing VEGF. Macrophage production of VEGF is upregulated by hypoxia and TGFbeta-1, both of which occur in the tumor environment. Macrophage production of VEGF is regulated at both the mRNA and protein levels.
BACKGROUND:Breast tumors contain high numbers of infiltrating macrophages. The role and function of these cells within the tumor remain unclear, but a number of studies have found an association between poor prognosis and macrophage content in humanbreast cancer. Both hypoxia and TGFbeta-1 have been shown to regulate VEGF in other cell types. We hypothesized that breast tumor-associated macrophages produce VEGF and that macrophage production of this factor is regulated by both hypoxia and TGFbeta-1. METHODS:Paraffin-embedded breast tumor sections were stained immunohistochemically with anti-VEGF, anti-CD68, and anti-cytokeratin. Monocytes were matured for 3 days in 20% autologous plasma and activated with 1000 U/mL interferon-gamma for 24 hours. Supernatants were assayed for VEGF protein by ELISA. Total RNA was isolated from cells and reverse transcribed to cDNA, which was used as a template in PCR reactions for VEGF and beta-actin. RESULTS: Both tumor cells and tumor macrophages produce VEGF in humanbreast tumors. Hypoxia increasesVEGF protein and mRNA levels in monocyte-derived macrophages, whereas TGFbeta-1 increases VEGF protein but not mRNA under hypoxic growth conditions. CONCLUSIONS:Breast tumor-associated macrophages may contribute to the angiogenic activity of humanbreast tumors by producing VEGF. Macrophage production of VEGF is upregulated by hypoxia and TGFbeta-1, both of which occur in the tumor environment. Macrophage production of VEGF is regulated at both the mRNA and protein levels.
Authors: S Cascinu; F Graziano; V Catalano; M P Staccioli; S Barni; P Giordani; M C Rossi; A M Baldelli; P Muretto; A Valenti; G Catalano Journal: Clin Exp Metastasis Date: 2000 Impact factor: 5.150
Authors: David P Kodack; Euiheon Chung; Hiroshi Yamashita; Joao Incio; Annique M M J Duyverman; Youngchul Song; Christian T Farrar; Yuhui Huang; Eleanor Ager; Walid Kamoun; Shom Goel; Matija Snuderl; Alisha Lussiez; Lotte Hiddingh; Sidra Mahmood; Bakhos A Tannous; April F Eichler; Dai Fukumura; Jeffrey A Engelman; Rakesh K Jain Journal: Proc Natl Acad Sci U S A Date: 2012-10-15 Impact factor: 11.205