Abstract P5-14-05: α-tocopherol succinate enhances the anti-tumor activity of pterostilbene against human breast cancer cells in vivo and in vitro

Background: The cancer preventive activity of vitamin E (α-tocopherol, α-TP) has been suggested by many epidemiologic studies. Our previous study showed that Tocopherol-Associated Protein (TAP), a major tocopherol–binding protein, is preferentially detected in normal breast tissues than in tumor regions among 93 clinical breast cancer patients, which postulate its tumor suppressive role in breast cells. Pterostilbene (3,5-dimethoxi-49-hydroxystilbene, PS) is a natural dimethylated analogue of Resveratrol found in different plants. Previous studies have shown that PS has the ability to induce apoptosis in a range of cancer cell lines. The purpose of our study was to assess the effect of TAP and Pterostilbene in tumor suppression of breast cancer cell.

Methods: Cell growth, proliferation, and viability were determined using the MTT assay. TAP protein expression was ablated in MDA-MB-231 breast cancer cell with nine independent siRNA sequences. MDA-MB-231 cells were transfected with pcDNA5 plasmids expressing the firefly luciferase gene. TAP protein expressions for each plasmid transfection were measured by western-blot analysis. Synergic effects of tumor growth and metastasis inhibitions in MDA-MB-231 xenograft animal model by PS and α-tocopherol treatment were evaluated.

Results: TAP served as a key molecular in responding to α-tocopheryl succinate (α-TOS) induced cell cycle regulation. PS has demonstrated the synergic decrease on breast cancer cell growth effects by the combination of α-TOS exposure. In animal model, treatment of PS and high level vitamin E diet not only induced breast tumor growth inhibition, but also suppressed tumor cell invasion by measuring circulation tumor cells in mouse blood.

Conclusions: Upon the evidences showed in this study, we suggest taking vitamin E and PS as supplements may provide both breast tumor preventative and therapeutic benefits in clinic.

Citation Format: Tam K-W, Lee C-H. α-tocopherol succinate enhances the anti-tumor activity of pterostilbene against human breast cancer cells in vivo and in vitro [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-14-05.