Requirement for sphingosine 1–phosphate receptor-1 in tumor angiogenesis demonstrated by in vivo RNA interference
Sung-Suk Chae, … , Henry Furneaux, Timothy Hla
Sung-Suk Chae, … , Henry Furneaux, Timothy Hla
Published October 15, 2004
Citation Information: J Clin Invest. 2004;114(8):1082-1089. https://doi.org/10.1172/JCI22716.
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Article Vascular biology

Requirement for sphingosine 1–phosphate receptor-1 in tumor angiogenesis demonstrated by in vivo RNA interference

Abstract

Angiogenesis, or new blood vessel formation, is critical for the growth and spread of tumors. Multiple phases of this process, namely, migration, proliferation, morphogenesis, and vascular stabilization, are needed for optimal tumor growth beyond a diffusion-limited size. The sphingosine 1–phosphate (S1P) receptor-1 (S1P1) is required for stabilization of nascent blood vessels during embryonic development. Here we show that S1P1 expression is strongly induced in tumor vessels. We developed a multiplex RNA interference technique to downregulate S1P1 in mice. The small interfering RNA (siRNA) for S1P1 specifically silenced the cognate transcript in endothelial cells and inhibited endothelial cell migration in vitro and the growth of neovessels into subcutaneous implants of Matrigel in vivo. Local injection of S1P1 siRNA, but not a negative control siRNA, into established tumors inhibited the expression of S1P1 polypeptide on neovessels while concomitantly suppressing vascular stabilization and angiogenesis, which resulted in dramatic suppression of tumor growth in vivo. These data suggest that S1P1 is a critical component of the tumor angiogenic response and argue for the utility of siRNA technology in antiangiogenic therapeutics.

Authors

Sung-Suk Chae, Ji-Hye Paik, Henry Furneaux, Timothy Hla

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Inhibition of angiogenesis in vivo by S1P1 siRNA. (A) Matrigel mixture c...
Inhibition of angiogenesis in vivo by S1P1 siRNA. (A) Matrigel mixture containing multiplex siRNA with or without FGF-2 was injected subcutaneously into athymic nude mice as described. The Matrigel plugs were harvested 7 days after implantation, fixed, sectioned, and H&E-stained as described. Images are obtained from a representative field of an experiment (n = 3) that was repeated twice. Scale bar: 100 μm. (B) The number of CD31-positive blood vessels in the Matrigel plugs was determined by immunohistochemistry and plotted (n = 4). Results represent mean ± SE. *P < 0.02. (C) Total RNA was isolated from the Matrigel plugs with siRNA for S1P1 or β-gal in the presence of FGF-2. S1P1 mRNA expression in the cells within Matrigel plugs was quantified by Northern blot analysis and normalized with respect to GAPDH expression (n = 3). **P < 0.1. In B and C, multiplex siS1P1 and siβ-gal indicate respective siRNAs in the presence of FGF-2 as described in A.