Pterostilbene and tamoxifen show an additive effect against breast cancer in vitro.
BACKGROUND
Tamoxifen is widely used for the treatment of breast cancer. Pterostilbene, a bioavailable stilbenoid found in blueberries, has been found to inhibit breast cancer growth in vitro. It was hypothesized that combining pterostilbene with tamoxifen would produce additive effects on estrogen receptor-positive breast cancer cells.


METHODS
Two estrogen receptor-positive breast cancer cell lines, MCF7 and ZR-751, were pretreated with graduated doses of pterostilbene for 24 hours, followed by 5 μmol/L tamoxifen. MTT proliferation assays and Cell Death Detection ELISA(PLUS) tests evaluated cell viability and apoptosis.


RESULTS
MCF7 cells showed inhibition (10 and 20 μmol/L, P < .001; 30 μmol/L, P < .05) at all time points when combined with tamoxifen. ZR-751 cells showed additive reductions in cell viability (P < .001). Cell Death Detection ELISA(PLUS) indicated increased apoptosis (P < .01).


CONCLUSIONS
Pterostilbene shows an additive inhibitory effect on breast cancer cells when combined with tamoxifen, most likely from augmented cancer cell apoptosis.
The University of Vermont/Fletcher Allen Health Care, Burlington, USA. patrick.mannal@vtmednet.org
Patrick
P
Mannal
Debbie
D
McDonald
David
D
McFadden
D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D035721:Pterocarpus; D013267:Stilbenes / Q000008:administration & dosage / Q000627:therapeutic use*; D013629:Tamoxifen / Q000008:administration & dosage / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured
D018931:Antineoplastic Agents, Hormonal; D013267:Stilbenes; D013629:Tamoxifen; C107773:pterostilbene