title: 2-MeOE2bisMATE induces caspase-dependent apoptosis in CAL51 breast cancer cells and overcomes resistance to TRAIL via cooperative activation of caspases.
abstract: 2-Methoxyoestradiol (2-MeOE2) is an endogenous oestrogen metabolite which inhibits tubulin polymerisation and has anti-tumour and anti-angiogenic activity. 2-MeOE2 induces apoptosis in a wide range of cancer cell types and has recently been demonstrated to cooperate with TRAIL to induce apoptosis in breast cancer cells. 2-Methoxyoestradiol-3,17-bis-O,O-sulphamate (2-MeOE2bisMATE) is a sulfamoylated derivative of 2-MeOE2 with enhanced activity and improved pharmacokinetic properties, and 2-MeOE2bisMATE is a promising candidate for early clinical trials. It is important, therefore, to understand the mechanisms by which 2-MeOE2bisMATE acts, and whether it retains the ability to cooperate with TRAIL. We demonstrate that 2-MeOE2bisMATE-induced apoptosis of CAL51 breast cancer cells was associated with rapid activation of caspase 3 and 9, but not caspase 8 (as measured by BID cleavage) and was completely prevented by the caspase inhibitor zVADfmk. Interfering with Fas- or TRAIL-receptor function did not prevent 2-MeOE2bisMATE-induced apoptosis. Whereas CAL51 cells were resistant to TRAIL-induced apoptosis, 2-MeOE2bisMATE and TRAIL cooperated to induce cell death. This apoptosis was associated with enhanced activation of caspases, but not increased expression of the DR5 TRAIL receptor, previously demonstrated to be induced by 2-MeOE2. Therefore, 2-MeOE2bisMATE-induced apoptosis is dependent on caspases and like 2-MeOE2, 2-MeOE2bisMATE can overcome resistance to TRAIL by stimulating activation of downstream caspases. Our results suggest that 2-MeOE2bisMATE and TRAIL might be a particularly effective combination of anti-cancer agents.
authors.affiliation: Cancer Research UK Oncology Unit, Cancer Sciences Research Division, University of Southampton School of Medicine, Southampton General Hospital, Southampton SO16 6YD, UK.
authors.forename: L
authors.initials: L
authors.lastname: Wood
authors.forename: M P
authors.initials: MP
authors.lastname: Leese
authors.forename: A
authors.initials: A
authors.lastname: Mouzakiti
authors.forename: A
authors.initials: A
authors.lastname: Purohit
authors.forename: B V L
authors.initials: BV
authors.lastname: Potter
authors.forename: M J
authors.initials: MJ
authors.lastname: Reed
authors.forename: G
authors.initials: G
authors.lastname: Packham
mesh_terms: D000077584:2-Methoxyestradiol; D000970:Antineoplastic Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D001682:Biological Availability; D001943:Breast Neoplasms / Q000473:pathology*; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000187:drug effects; D004958:Estradiol / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology*; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D015394:Molecular Structure; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: C500344:2-methoxyestradiol-3,17-bis-O,O-sulfamate; D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D004958:Estradiol; D000077584:2-Methoxyestradiol; D020169:Caspases