title: Diallyl trisulfide inhibits angiogenic features of human umbilical vein endothelial cells by causing Akt inactivation and down-regulation of VEGF and VEGF-R2.
abstract: We have shown recently that diallyl trisulfide (DATS), a cancer-chemopreventive constituent of garlic, inactivates Akt to trigger mitochondrial translocation of proapoptotic protein BAD in human prostate cancer cells. Because Akt activation is implicated in the promotion of endothelial cell survival and angiogenesis, we hypothesized that DATS may inhibit angiogenesis. In the present study, we tested this hypothesis using human umbilical vein endothelial cells (HUVECs) as a model. Survival of HUVECs was reduced significantly in the presence of DATS in a concentration-dependent manner, with an IC50 of approximately 4 microM. The DATS-mediated suppression of HUVEC survival was associated with apoptosis induction characterized by accumulation of subdiploid cells, cytoplasmic histone-associated DNA fragmentation, and cleavage of caspase-3 and poly-(ADP-ribose)-polymerase. The DATS-induced DNA fragmentation was significantly attenuated in the presence of pan-caspase inhibitor zVAD-fmk and specific inhibitors of caspase-9 (zLEHD-fmk) and caspase-8 (zIETD-fmk). DATS treatment inhibited the formation of capillary-like tube structure and migration by HUVECs in association with suppression of vascular endothelial growth factor (VEGF) secretion and VEGF receptor-2 protein level and inactivation of Akt kinase. DATS treatment also caused activation of extracellular signal-regulated kinase 1/2 (ERK1/2) but not c-Jun NH2-terminal kinase (JNK) or p38 mitogen-activated protein kinase (p38MAPK).DATS-mediatedapoptosis induction and inhibition of HUVEC tube formation was partially but statistically significantly attenuated by pharmacologic inhibition of ERK1/2 but not JNK or p38MAPK. The present study demonstrates, for the first time, that DATS has the ability to inhibit angiogenic features of human endothelial cells.
authors.affiliation: University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Xiao
authors.forename: Mengfeng
authors.initials: M
authors.lastname: Li
authors.forename: Anna
authors.initials: A
authors.lastname: Herman-Antosiewicz
authors.forename: Jedrzej
authors.initials: J
authors.lastname: Antosiewicz
authors.forename: Hui
authors.initials: H
authors.lastname: Xiao
authors.forename: Karen L
authors.initials: KL
authors.lastname: Lew
authors.forename: Yan
authors.initials: Y
authors.lastname: Zeng
authors.forename: Stanley W
authors.initials: SW
authors.lastname: Marynowski
authors.forename: Shivendra V
authors.initials: SV
authors.lastname: Singh
mesh_terms: D000498:Allyl Compounds / Q000494:pharmacology*; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D042783:Endothelial Cells / Q000187:drug effects*; D005737:Garlic / Q000737:chemistry; D006801:Humans; D020128:Inhibitory Concentration 50; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects* / Q000378:metabolism; D013440:Sulfides / Q000494:pharmacology*; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A / Q000187:drug effects / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000498:Allyl Compounds; D020533:Angiogenesis Inhibitors; D013440:Sulfides; D042461:Vascular Endothelial Growth Factor A; C042577:diallyl trisulfide; D040301:Vascular Endothelial Growth Factor Receptor-2; D051057:Proto-Oncogene Proteins c-akt; D020169:Caspases