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ABSTRACT: Age-related macular degeneration is the leading cause of blindness in the elderly. Choroidal neovascularization (CNV) leads to severe vision loss in patients of age-related macular degeneration. Previously, we have demonstrated that deguelin, isolated from plants in the Mundulea sericea family, is a chemopreventive agent. This study evaluates the antiangiogenic effect of deguelin on CNV. The toxicity of deguelin was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay in human umbilical vein endothelial cells (HUVECs) as well as histological examination and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining in the deguelin-injected retina. Antiangiogenic activity of deguelin was evaluated by in vitro tube formation assay of HUVECs and in vivo angiogenesis of chick chorioallantoic membrane (CAM). In C57BL/6 mice with laser-induced CNV, deguelin or phosphate-buffered saline was injected intravitreously. CNV lesions were examined by fluorescence angiography and vessel counting in cross-sections. Deguelin showed no effect on cell viability of HUVECs and no retinal toxicity in a concentration range of 0.01 to 1 microM. Deguelin effectively inhibited in vitro tube formation of HUVECs and in vivo angiogenesis of CAM. Interestingly, deguelin significantly reduced CNV and its leakage in mouse model of laser photocoagulation-induced CNV. Our data suggests that deguelin is a potent inhibitor of CNV and may be applied in the treatment of other vasoproliferative retinopathies such as retinopathy of prematurity and diabetic retinopathy.
Journal of Pharmacology and Experimental Therapeutics 03/2008; 324(2):643-7. · 3.83 Impact Factor
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ABSTRACT: Hypoxia-inducible factor 1 (HIF-1) plays an essential role in tumor angiogenesis and growth by regulating the transcription of several genes in response to hypoxic stress and changes in growth factors. This study was designed to investigate the effects of deguelin on tumor growth and angiogenesis, and the mechanisms underlying the antitumor activities of deguelin. We show here that orally administered deguelin inhibits tumor growth and blocks tumor angiogenesis in mice. Deguelin decreased expression of HIF-1alpha protein and its target genes, such as VEGF, in a subset of cancer cell lines, including H1299 lung cancer cells, and vascular endothelial cells in normoxic and hypoxic conditions. Overexpression of vascular endothelial growth factor by adenoviral vector infection abolished the antiangiogenic effects of deguelin on H1299 nonsmall cell lung cancer cells. Deguelin inhibited de novo synthesis of HIF-1alpha protein and reduced the half-life of the synthesized protein. MG132, a proteasome inhibitor, protected the hypoxia- or IGF-induced HIF-1alpha protein from deguelin-mediated degradation. Our findings suggest that deguelin is a promising antiangiogenic therapeutic agent in cancer targeting HIF-1alpha. Considering that HIF-1alpha is overexpressed in a majority of human cancers, deguelin could offer a potent therapeutic agent for cancer.
International Journal of Cancer 02/2008; 122(1):5-14. · 5.44 Impact Factor
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Moon-Kyoung Bae,
Joo-Won Jeong,
Se-Hee Kim,
Soo-Young Kim, Hye Jin Kang,
Dong-Min Kim,
Soo-Kyung Bae,
Il Yun,
Grace A Trentin,
Maria Rozakis-Adcock,
Kyu-Won Kim
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ABSTRACT: The von Hippel-Lindau protein (pVHL) is a major tumor suppressor protein and also associated with the inhibition of angiogenesis via HIF-1alpha ubiquitination and proteasomal degradation. To further elucidate the biological activity of pVHL in angiogenesis, pVHL-interacting proteins were screened using the yeast two-hybrid system. We found that a mouse homologue of the long form of Drosophila tumor suppressor l(2)tid, Tid-1(L), directly interacts with pVHL in vitro and in vivo. Furthermore, Tid-1(L) protein; enhanced the interaction between HIF-1alpha and pVHL, leading to the destabilization of HIF-1alpha protein; therefore, Tid-1(L) protein decreased vascular endothelial growth factor expression and inhibited angiogenesis in vivo and in vitro. These findings propose that Tid-1(L) may play a critical role in pVHL-mediated tumor suppression by modulating the pVHL-dependent HIF-1alpha stability.
Cancer Research 05/2005; 65(7):2520-5. · 7.86 Impact Factor
