Vitamin C suppresses cell death in MCF‐7 human breast cancer cells induced by tamoxifen

• Published in: Journal of cellular and molecular medicine 2014-02, Vol.18 (2), p.305-313
• Main Authors: Subramani, Tamilselvan, Yeap, Swee Keong, Ho, Wan Yang, Ho, Chai Ling, Omar, Abdul Rahman, Aziz, Suraini Abdul, Rahman, Nik Mohd. Afizan Nik Abd, Alitheen, Noorjahan Banu
• Format: Article
• Language: English
• Subjects: Acridine; Annexin A5; Annexin V; Antiestrogens; Antineoplastic Agents, Hormonal - pharmacology; Apoptosis; Ascorbic acid; Breast cancer; Cancer therapies; Caspase; Caspase 8 - genetics; Caspase 8 - metabolism; Cell death; Cell Death - drug effects; Cell Line, Tumor; Cholesterol; Cytotoxicity; Dehydroascorbic Acid - metabolism; Dehydroascorbic Acid - pharmacology; Dose-Response Relationship, Drug; Esterification; Fas Ligand Protein - genetics; Fas Ligand Protein - metabolism; FasL protein; Female; free radical; Humans; Iodides; Lipid peroxidation; Lipid Peroxidation - drug effects; Membrane potential; Membrane Potential, Mitochondrial - drug effects; Mitochondria; mRNA; Original; Peroxidation; Propidium; Propidium iodide; Reactive oxygen species; Reactive Oxygen Species - metabolism; ROS; Supplements; Tamoxifen; Tamoxifen - antagonists & inhibitors; Tamoxifen - pharmacology; Tumor necrosis factor; Tumor Necrosis Factor-alpha - genetics; Tumor Necrosis Factor-alpha - metabolism; Tumors; Vitamin C; Vitamin E
• ISSN: 1582-1838; 1582-4934
• DOI: 10.1111/jcmm.12188

Vitamin C is generally thought to enhance immunity and is widely taken as a supplement especially during cancer treatment. Tamoxifen (TAM) has both cytostatic and cytotoxic properties for breast cancer. TAM engaged mitochondrial oestrogen receptor beta in MCF‐7 cells and induces apoptosis by activation of pro‐caspase‐8 followed by downstream events, including an increase in reactive oxygen species and the release of pro‐apoptotic factors from the mitochondria. In addition to that, TAM binds with high affinity to the microsomal anti‐oestrogen‐binding site and inhibits cholesterol esterification at therapeutic doses. This study aimed to investigate the role of vitamin C in TAM‐mediated apoptosis. Cells were loaded with vitamin C by exposure to dehydroascorbic acid, thereby circumventing in vitro artefacts associated with the poor transport and pro‐oxidant effects of ascorbic acid. Pre‐treatment with vitamin C caused a dose‐dependent attenuation of cytotoxicity, as measured by acridine‐orange/propidium iodide (AO/PI) and Annexin V assay after treatment with TAM. Vitamin C dose‐dependently protected cancer cells against lipid peroxidation caused by TAM treatment. By real‐time PCR analysis, an impressive increase in FasL and tumour necrosis factor‐α (TNF‐α) mRNA was detected after TAM treatment. In addition, a decrease in mitochondrial transmembrane potential was observed. These results support the hypothesis that vitamin C supplementation during cancer treatment may detrimentally affect therapeutic response.