Involvement of de novo ceramide synthesis in gamma-tocopherol and gamma-tocotrienol-induced apoptosis in human breast cancer cells.

Abstract

SCOPE:

This study further examines mechanisms involved in the pro-apoptotic action of gamma-tocopherol (γT) and gamma-tocotrienol (γT3) in human breast cancer cell lines.

METHODS AND RESULTS:

γT upregulates phospho-JNK (pJNK), CCAAT/enhancer-binding protein homologous protein (CHOP), and death receptor-5 (DR5) protein expression as detected by Western blot assays. siRNA knockdown of JNK, CHOP, or DR5 shows that γT-induced apoptosis is JNK/CHOP/DR5 signaling dependent, which is similar to γT3-mediated apoptotic signaling. Furthermore, both γT and γT3 induce increased levels of cellular ceramides and dihydroceramides as determined by LC-MS/MS analyses. Inhibition of de novo ceramide synthesis using chemical inhibitors blocked the ability of γT and γT3 to induce apoptosis as detected by Annexin V-FITC/PI assay and to activate JNK/CHOP/DR5 pro-apoptotic signaling thereby demonstrating the involvement of de novo ceramide synthesis in γT- and γT3-induced apoptosis.

CONCLUSION:

Taken together, data show that both γT and γT3 induce apoptosis via de novo ceramide synthesis dependent activation of JNK/CHOP/DR5 pro-apoptotic signaling.

• Authors: Archana Gopalan, Weiping Yu, Qing Jiang, Yumi Jang, Bob G Sanders, Kimberly Kline
• Journal: Molecular nutrition & food research (Mol Nutr Food Res) Vol. 56 Issue 12 Pg. 1803-11 (Dec 2012) ISSN: 1613-4133 [Electronic] Germany
• PMID: 23065795 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical References

• Ceramides
• Chromans
• DDIT3 protein, human
• RNA, Small Interfering
• Receptors, TNF-Related Apoptosis-Inducing Ligand
• TNFRSF10B protein, human
• Vitamin E
• Transcription Factor CHOP
• plastochromanol 8
• gamma-Tocopherol
• JNK Mitogen-Activated Protein Kinases

Topics

• Apoptosis (drug effects)
• Blotting, Western
• Breast Neoplasms (pathology)
• Cell Line, Tumor
• Ceramides (biosynthesis)
• Chromans (pharmacology)
• Chromatography, Liquid
• Female
• Humans
• JNK Mitogen-Activated Protein Kinases (genetics, metabolism)
• MCF-7 Cells
• RNA, Small Interfering (genetics, isolation & purification)
• Receptors, TNF-Related Apoptosis-Inducing Ligand (genetics, metabolism)
• Signal Transduction
• Tandem Mass Spectrometry
• Transcription Factor CHOP (genetics, metabolism)
• Up-Regulation
• Vitamin E (analogs & derivatives, pharmacology)
• gamma-Tocopherol (pharmacology)