Resveratrol potentiates grape seed extract induced human colon cancer cell apoptosis
Sridhar Radhakrishnan1, Lavanya Reddivari1, Robert Sclafani2, Undurti N Das3, Jairam Vanamala1,4
1
Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, Colorado, USA, 2The Program in Molecular Biology, University of Colorado School of Medicine, Aurora, Colorado, USA, 3UND Life Sciences, Shaker Heights, Ohio, USA, 4Cancer Chemoprevention Section, University of Colorado Cancer Center, Aurora, Colorado, USA
TABLE OF CONTENTS
- 1. Abstract
- 2. Introduction
- 3. Materials and methods
- 3.1. Chemicals
- 3.2. LC-MS analysis of GSE
- 3.3. Cell lines
- 3.4. Cell proliferation assay
- 3.5. Cytotoxicity detection
- 3.6. Apoptosis assay
- 3.7. Experimental design of combination study
- 3.8. Fluorescence-activated cell sorting analysis (FACS)
- 3.9. Western blot analysis
- 3.10. IGF-1 treatment 3.11. Statistical analysis 4. Results
- 4.1. Resveratrol (RSV) or grape seed extract (GSE) suppresses cell proliferation of HCT-116 cells
- 4.2. RSV or GSE induces apoptosis
- 4.3. RSV-GSE combination suppresses cell proliferation and induces apoptosis
- 4.4. RSV-GSE combination induces cell cycle arrest in Go/G1 phase in both HCT 116 p53 +/+ and p53 -/- cells
- 4.5. RSV-GSE combination induces apoptosis via p53-dependent pathway
- 4.6. RSV-GSE combination suppressed cell proliferation and induced apoptosis via caspase-3-dependent and Bax/Bcl-2 pathways.
- 4.7. N-acetyl cysteine (NAC) inhibited RSV-GSE combination induced apoptosis in HCT-116 p53 +/+ cells
- 4.8. RSV-GSE combination is non-toxic to normal cells
- 4.9. RSV-GSE combination suppressed cell proliferation and induced apoptosis even in the presence of IGF-1
- 5. Discussion
- 6. Acknowledgements
- 7. References
1. ABSTRACT
Colon cancer is the third leading cause of cancer deaths in men and women. Grape seed extract (GSE) and resveratrol (RSV) are potent chemopreventive agents against colon cancer both in vitro and in vivo, at relatively high concentrations. We hypothesized that RSV and GSE may act in concert with each other in potentiating their anti-cancer properties at sub-optimal doses, because they occur as complex mixtures in grapes. In this study, we showed that RSV (~25 micromolar) potentiated GSE (≤ 35 microg/mL) induced colon cancer cell apoptosis via activation of p53 dependent pathways. Elevation of apoptosis was much more pronounced in p53 +/+ cells compared to p53 -/- cells. Apoptosis was strongly correlated with pp53 levels and Bax:Bcl-2 ratio, key players in the mitochondrial apoptotic pathway. Caspase-3 inhibition and reactive oxygen species suppression attenuated apoptosis induced by the combination. RSV-GSE combination suppressed proliferation and induced apoptosis even in the presence of mitogenic growth factor IGF-1, suggesting the importance of understanding the potentiating effects of phytonutrients in combination as they would occur in nature rather than individually.
