Topical Area: Dietary Bioactive Components
Objectives : Caffeine is a widely consumed phytochemical naturally occurring in coffee and tea, or added to beverages such as energy drinks used to promote wakefulness and alertness. Previous research suggests that MCF-7 breast cancer cell viability decreases after exposure to millimolar (mM) amounts of caffeine in vitro. The effect of smaller, micromolar (µM), amounts of caffeine has not been fully investigated. This in vitro study investigates the impact of varying µM concentrations of caffeine on MCF-7 cell proliferation.
Methods : MCF-7 cells were cultured and treated with caffeine concentrations that followed a serial dilution curve from 10µM to 1.2mM, and 5mM of caffeine, a concentration that previous study has suggested as cytotoxic to MCF-7 cells. Both a media control (0µM caffeine concentration) and a vehicle control (distilled water) were included. After 24 hours of treatment exposure, an XTT assay calculated MCF-7 cell proliferation. The experiment was run in triplicate and each caffeine concentration was tested three times during each run.
Results : After a 24-hour period, a bimodal result was noted. When compared to the media control (0µM caffeine concentration), the 10µM caffeine concentration showed 91-107% cell proliferation; 20µM at 104-145%; 40µM at 99-115%; 80µM at 80-96%; 160µM at 80-83%; 320µM at 76-97%; 640µM at 65-81%; 1.2mM at 57-80%; 5mM at 37-50%. A paired samples t-test done for the vehicle control indicated effects on cell proliferation were due to the caffeine concentration, rather than the distilled water (p=0.54).
Conclusions : This data reflects previous research suggesting that caffeine is cytotoxic to MCF-7 cells in vitro at the 5mM concentration. In addition, percentage and t-test data suggest µM concentrations of caffeine have a bimodal effect on MCF-7 cells in vitro, with an initial increase in cell proliferation from 10µM to 40µM of caffeine and a potential starting concentration of cytotoxic effect at 80µM of caffeine.
Funding Sources : Funding provided by Bastyr University Faculty Student Research Grant.