title: α-TEA induces apoptosis of human breast cancer cells via activation of TRAIL/DR5 death receptor pathway.
abstract: Vitamin E derivative RRR-α-tocopherol ether-linked acetic acid analog (α-TEA) induces apoptosis in MCF-7 and HCC-1954 human breast cancer cells in a dose- and time-dependent manner. α-TEA induces increased levels of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and death receptor-5 (DR5) and decreased levels of antiapoptotic factor, cellular FLICE-like inhibitory protein (c-FLIP L). DR5/TRAIL induced apoptosis involves downregulation of c-FLIP (L), caspase-8 activation, activated proapoptotic mediators tBid and Bax, mitochondrial permeability transition, and activation of caspase-9. siRNA knockdown of either DR5 or TRAIL blocks the ability of α-TEA to enhance DR5 protein levels, downregulate c-FLIP(L) protein levels and induce apoptosis. Combination of α-TEA + TRAIL acts cooperatively to induce apoptosis, and increase DR5 and decrease c-FLIP (L) protein levels. siRNA knockdown of c-FLIP produces a low level of spontaneous apoptosis and enhances α-TEA- and TRAIL-induced apoptosis. Taken together, these studies show that α-TEA induces TRAIL/DR5 mitochondria-dependent apoptosis in human breast cancer cells, and that TRAIL/DR5-dependent increases in DR5 and decreases in c-FLIP expression are triggered by TRAIL or α-TEA treatments.
authors.affiliation: University of Texas at Austin, USA.
authors.forename: Weiping
authors.initials: W
authors.lastname: Yu
authors.forename: Richa
authors.initials: R
authors.lastname: Tiwary
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Sook-Kyung
authors.initials: SK
authors.lastname: Park
authors.forename: Li
authors.initials: L
authors.lastname: Jia
authors.forename: Ailian
authors.initials: A
authors.lastname: Xiong
authors.forename: Marla
authors.initials: M
authors.lastname: Simmons-Menchaca
authors.forename: Bob G
authors.initials: BG
authors.lastname: Sanders
authors.forename: Kimberly
authors.initials: K
authors.lastname: Kline
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014810:Vitamin E / Q000031:analogs & derivatives; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C519038:RRR-alpha-tocopheryloxybutyrate; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; D014810:Vitamin E; D045304:Cytochromes c; D053181:Caspase 8; D053453:Caspase 9; D024502:alpha-Tocopherol