title: γ-Tocotrienol inhibits HGF-dependent mitogenesis and Met activation in highly malignant mammary tumour cells.
abstract: OBJECTIVE
  Aberrant Met signalling is associated with aggressive cancer cell phenotypes. γ-tocotrienol displays potent anti-cancer activity that is associated with suppression of HER/ErbB receptor signalling. Experiments were conducted to investigate the effects of γ-tocotrienol treatment on HGF-dependent +SA mammary tumour cell proliferation, upon Met activation.
  
  
  METHODS
  The +SA cells were maintained in serum-free defined media containing 10 ng/ml HGF as the mitogen. Cell viability was determined using the MTT assay, western blot analysis was used to measure protein expression, and Met expression and activation were determined using immunofluorescent staining.
  
  
  CONCLUSIONS
  Treatment with γ-tocotrienol or Met inhibitor, SU11274, significantly inhibited HGF-dependent +SA cell replication in a dose-responsive manner. Treatment with 4 μmγ-tocotrienol reduced both total Met levels and HGF-induced Met autophosphorylation. In contrast, similar treatment with 5.5 μm SU11274 inhibited HGF-induced Met autophosphorylation, but had no effect on total Met levels. Combined treatment with subeffective doses of γ-tocotrienol (2 μm) and SU11274 (3 μm) resulted in significant inhibition of +SA cell expansion compared to treatment with individual agents alone. These findings show, for the first time, the inhibitory effects of γ-tocotrienol on Met expression and activation, and strongly suggest that γ-tocotrienol treatment may provide significant health benefits in prevention and/or treatment of breast cancer, in women with deregulated HGF/Met signalling.
authors.affiliation: College of Pharmacy, University of Louisiana at Monroe, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Ayoub
authors.forename: S V
authors.initials: SV
authors.lastname: Bachawal
authors.forename: P W
authors.initials: PW
authors.lastname: Sylvester
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002839:Chromans / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D005260:Female; D017228:Hepatocyte Growth Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: C478479:((3Z)-N-(3-chlorophenyl)-3-((3,5-dimethyl-4-((4-methylpiperazin-1-yl)carbonyl)-1H-pyrrol-2-yl)methylene)-N-methyl-2-oxo-2,3-dihydro-1H-indole-5-sulfonamide); D000970:Antineoplastic Agents; D002839:Chromans; C553307:HGF protein, mouse; D007211:Indoles; D008934:Mitogens; D010879:Piperazines; D013449:Sulfonamides; D014810:Vitamin E; C013649:plastochromanol 8; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met