Inhibition of angiogenesis and endothelial cell functions are novel sulforaphane-mediated mechanisms in chemoprevention.
Sulforaphane, an aliphatic isothiocyanate, is a known cancer chemopreventive agent. Aiming to investigate antiangiogenic potential of sulforaphane, we here report a potent decrease of newly formed microcapillaries in a human in vitro antiangiogenesis model, with an IC50 of 0.08 micromol/L. The effects of sulforaphane on endothelial cell functions essential for angiogenesis were investigated in HMEC-1, an immortalized human microvascular endothelial cell line. Molecular signaling pathways leading to activation of endothelial cell proliferation and degradation of the basement membrane were analyzed by reverse transcription-PCR. Sulforaphane showed time- and concentration-dependent inhibitory effects on hypoxia-induced mRNA expression of vascular endothelial growth factor and two angiogenesis-associated transcription factors, hypoxia-inducible factor-1alpha and c-Myc, in a concentration range of 0.8 to 25 micromol/L. In addition, the expression of the vascular endothelial growth factor receptor KDR/flk-1 was inhibited by sulforaphane at the transcriptional level. Sulforaphane could also affect basement membrane integrity, as it suppressed transcription of the predominant endothelial collagenase matrix metalloproteinase-2 and its tissue inhibitor of metalloproteinase-2. Migration of HMEC-1 cells in a wound healing assay was effectively prevented by sulforaphane at submicromolar concentrations, and we determined an IC50 of 0.69 micromol/L. In addition, within 6 hours of incubation, sulforaphane inhibited tube formation of HMEC-1 cells on basement membrane matrix at 0.1, 1, and 10 micromol/L concentrations. These effects were not due to inhibition of HMEC-1 cell proliferation; however, after 72 hours of incubation, sulforaphane nonselectively reduced HMEC-1 cell growth with an IC50 of 11.3 micromol/L. In conclusion, we have shown that sulforaphane interferes with all essential steps of neovascularization from proangiogenic signaling and basement membrane integrity to endothelial cell proliferation, migration, and tube formation. These novel antiangiogenic activities of sulforaphane are likely to contribute to its cancer chemopreventive and therapeutic potential.
Division of Toxicology and Cancer Risk Factors, German Cancer Research Center, C010-2 Chemoprevention, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
Elisabeth
E
Bertl
Helmut
H
Bartsch
Clarissa
C
Gerhäuser
D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D001485:Basement Membrane / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism; D017879:Isothiocyanates; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D009369:Neoplasms / Q000098:blood supply; D009389:Neovascularization, Pathologic / Q000517:prevention & control; D018919:Neovascularization, Physiologic / Q000187:drug effects; D013454:Sulfoxides; D013861:Thiocyanates / Q000627:therapeutic use*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D020533:Angiogenesis Inhibitors; D016588:Anticarcinogenic Agents; D051793:Hypoxia-Inducible Factor 1; D017879:Isothiocyanates; D013454:Sulfoxides; D013861:Thiocyanates; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D019716:Tissue Inhibitor of Metalloproteinase-2; D020778:Matrix Metalloproteinase 2; C016766:sulforaphane