A BMP7 Variant Inhibits Tumor Angiogenesis In Vitro and In Vivo through Direct Modulation of Endothelial Cell Biology

PLoS One. 2015 Apr 28;10(4):e0125697. doi: 10.1371/journal.pone.0125697. eCollection 2015.

Abstract

Bone morphogenetic proteins (BMPs), members of the TGF-β superfamily, have numerous biological activities including control of growth, differentiation, and vascular development. Using an in vitro co-culture endothelial cord formation assay, we investigated the role of a BMP7 variant (BMP7v) in VEGF, bFGF, and tumor-driven angiogenesis. BMP7v treatment led to disruption of neo-endothelial cord formation and regression of existing VEGF and bFGF cords in vitro. Using a series of tumor cell models capable of driving angiogenesis in vitro, BMP7v treatment completely blocked cord formation. Pre-treatment of endothelial cells with BMP7v significantly reduced their cord forming ability, indicating a direct effect on endothelial cell function. BMP7v activated the canonical SMAD signaling pathway in endothelial cells but targeted gene knockdown using shRNA directed against SMAD4 suggests this pathway is not required to mediate the anti-angiogenic effect. In contrast to SMAD activation, BMP7v selectively decreased ERK and AKT activation, significantly decreased endothelial cell migration and down-regulated expression of critical RTKs involved in VEGF and FGF angiogenic signaling, VEGFR2 and FGFR1 respectively. Importantly, in an in vivo angiogenic plug assay that serves as a measurement of angiogenesis, BMP7v significantly decreased hemoglobin content indicating inhibition of neoangiogenesis. In addition, BMP7v significantly decreased angiogenesis in glioblastoma stem-like cell (GSLC) Matrigel plugs and significantly impaired in vivo growth of a GSLC xenograft with a concomitant reduction in microvessel density. These data support BMP7v as a potent anti-angiogenic molecule that is effective in the context of tumor angiogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / cytology
  • Animals
  • Bone Morphogenetic Protein 7 / pharmacology
  • Bone Morphogenetic Protein 7 / therapeutic use*
  • Cell Death / drug effects
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Collagen / pharmacology
  • Drug Combinations
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism*
  • Fibroblast Growth Factor 2 / metabolism
  • Glioblastoma / blood supply*
  • Human Umbilical Vein Endothelial Cells / drug effects
  • Human Umbilical Vein Endothelial Cells / metabolism
  • Humans
  • Laminin / pharmacology
  • Male
  • Mice, Nude
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism
  • Neovascularization, Pathologic / drug therapy*
  • Neovascularization, Pathologic / pathology
  • Neovascularization, Physiologic / drug effects
  • Proteoglycans / pharmacology
  • Receptor, Fibroblast Growth Factor, Type 1 / metabolism
  • Signal Transduction / drug effects
  • Smad Proteins / metabolism
  • Vascular Endothelial Growth Factor A / metabolism
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • Bone Morphogenetic Protein 7
  • Drug Combinations
  • Laminin
  • Proteoglycans
  • Smad Proteins
  • Vascular Endothelial Growth Factor A
  • Fibroblast Growth Factor 2
  • matrigel
  • Collagen
  • Receptor, Fibroblast Growth Factor, Type 1
  • Vascular Endothelial Growth Factor Receptor-2

Grant support

This study was supported by Eli Lilly. The funders did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the "author contributions" section.