A naturally occurring mixture of tocotrienols inhibits the growth of human prostate tumor, associated with epigenetic modifications of cyclin-dependent kinase inhibitors p21 and p27.

Abstract

Tocotrienols, members of the vitamin E family, have three unsaturated bonds in their side chains. Recently, it has been suggested that the biological effects of tocotrienols may differ from that of tocopherols. Several in vitro studies have shown that tocotrienols have stronger anticancer effects than tocopherols. VCaP cell line used in this study is from a vertebral bone metastasis from a patient with prostate cancer. Eight-week-old male NCr(-/-) nude mice were subcutaneously injected with VCaP-luc cells in matrigel and then administered a tocotrienol mixture for 8 weeks. The tocotrienol mixture inhibited the growth of human prostate tumor xenografts in a dose-dependent manner. The concentrations of tocotrienols and their metabolites were significantly increased in treatment groups. Tocotrienols inhibited prostate tumor growth by suppressing cell proliferation, which was associated with the induction of the cyclin-dependent kinase (CDK) inhibitors p21 and p27. In addition, tocotrienol treatment was associated with elevated H3K9 acetylation levels at proximal promoter regions of p21 and p27 and with decreased expression of histone deacetylases. Tocotrienols inhibited human prostate tumor growth, associated with up-regulation of the CDK inhibitors p21 and p27. Elevated expression of p21 and p27 could be partly due to the suppressed expression of HDACs.

• Authors: Ying Huang, Renyi Wu, Zheng-Yuan Su, Yue Guo, Xi Zheng, Chung S Yang, Ah-Ng Kong
• Journal: The Journal of nutritional biochemistry (J Nutr Biochem) Vol. 40 Pg. 155-163 (02 2017) ISSN: 1873-4847 [Electronic] United States
• PMID: 27889685 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical References

• CDKN1A protein, human
• Cyclin-Dependent Kinase Inhibitor p21
• Histones
• Tocotrienols
• Cyclin-Dependent Kinase Inhibitor p27

Topics

• Acetylation (drug effects)
• Administration, Oral
• Animals
• Cell Cycle (drug effects)
• Cell Line, Tumor
• Cyclin-Dependent Kinase Inhibitor p21 (genetics)
• Cyclin-Dependent Kinase Inhibitor p27 (genetics)
• Epigenesis, Genetic (drug effects)
• Gene Expression Regulation, Neoplastic (drug effects)
• Histones (metabolism)
• Humans
• Male
• Mice, Nude
• Prostatic Neoplasms (drug therapy, genetics, pathology)
• Tocotrienols (administration & dosage, pharmacokinetics, pharmacology)
• Xenograft Model Antitumor Assays