The influence of lycopene on the proliferation of human breast cell line (mcf-7)

Lycopene, a non-provitaminic carotenoid, present in many fruit and vegetables, such as tomatoes and their processed products, has been associated with decreased risk of chronic diseases including cancer. The influence of lycopene on the proliferation of the breast tumour cell line (MCF-7) was tested using MTT and BrdU assays at different time intervals and dose–response. The induction of Gap Junction Intercellular Communication (GJIC) was evaluated by dye-transfer assay using Lucifer Yellow on monolayer cells treated with different lycopene concentrations for 6 to 48 h. The Minimal Inhibitory Concentration (MIC) of lycopene was of 5 mM, after a 24 h exposure. A prolonged exposure time induced a similar inhibitory effect. Lycopene stimulated the functionality of GJIC at concentrations of 1 mM after 24 h and this effect was dose-dependent. The induction of GJIC by lycopene was confirmed by an increased expression of connexin 43. Collectively, the above data confirm the inhibitor effects of lycopene on MCF-7 cell growth and suggest that lycopene is involved in the modulation of the gap junction intercellular communication in this cell line, as observed for other cancer cell lines.