PURPOSE: Vitamin D compounds have been shown to inhibit tumor growth in a transgenic retinoblastoma murine model. The mechanism of action has not been defined clearly, although an antiangiogenic action has been proposed. METHODS: Transgenic retinoblastoma mice received high (0.05 microgram) and low (0.025 microgram) doses of vitamin D3 by intraperitoneal injection 5 times per week for 5 weeks. Control animals were injected with mineral oil vehicle alone. At 5 months of age, the animals were killed and eyes were enucleated and processed for light microscopy. Paraffin-embedded sections were stained with an immunoperoxidase stain (GS-1) specific for mammalian vascular endothelium. Sections were graded by a single masked reviewer, and intraobserver reliability was assessed. Mean vessel counts were made for each group. RESULTS: The high-dose group had the lowest mean vessel count (8.5), followed by the low-dose group (10.1). The control group had the highest mean vessel count (14.1). Vitamin D-treated animals (high- and low-dose groups combined) had significantly fewer vessels P = 0.001) than untreated controls. CONCLUSIONS: These results support the hypothesis that inhibition of angiogenesis is a mechanism of action for vitamin D in the transgenic retinoblastoma mouse model.
PURPOSE:Vitamin D compounds have been shown to inhibit tumor growth in a transgenic retinoblastomamurine model. The mechanism of action has not been defined clearly, although an antiangiogenic action has been proposed. METHODS:Transgenic retinoblastomamice received high (0.05 microgram) and low (0.025 microgram) doses of vitamin D3 by intraperitoneal injection 5 times per week for 5 weeks. Control animals were injected with mineral oil vehicle alone. At 5 months of age, the animals were killed and eyes were enucleated and processed for light microscopy. Paraffin-embedded sections were stained with an immunoperoxidase stain (GS-1) specific for mammalian vascular endothelium. Sections were graded by a single masked reviewer, and intraobserver reliability was assessed. Mean vessel counts were made for each group. RESULTS: The high-dose group had the lowest mean vessel count (8.5), followed by the low-dose group (10.1). The control group had the highest mean vessel count (14.1). Vitamin D-treated animals (high- and low-dose groups combined) had significantly fewer vessels P = 0.001) than untreated controls. CONCLUSIONS: These results support the hypothesis that inhibition of angiogenesis is a mechanism of action for vitamin D in the transgenic retinoblastomamouse model.
Authors: Amy E Millen; Rick Voland; Sherie A Sondel; Niyati Parekh; Ronald L Horst; Robert B Wallace; Gregory S Hageman; Rick Chappell; Barbara A Blodi; Michael L Klein; Karen M Gehrs; Gloria E Sarto; Julie A Mares Journal: Arch Ophthalmol Date: 2011-04
Authors: Alejandro S Godoy; Ivy Chung; Viviana P Montecinos; Ralph Buttyan; Candace S Johnson; Gary J Smith Journal: Am J Physiol Endocrinol Metab Date: 2013-04-02 Impact factor: 4.310