p-Hydroxybenzoate esters metabolism in MCF7 breast cancer cells.

Parabens are among the most frequently used preservatives to inhibit microbial growth and extend the shelf life of a range of consumer products. The objective of the present study was to gain insight into the metabolism of parabens in breast cancer cells (MCF7) since they have demonstrated estrogenic activity towards these cells and have been detected in breast cancer tissues. The toxicity of parabens to MCF7 cells was determined using MTT assays. Hydrolysis of methyl-, butyl and benzyl-paraben to p-hydroxybenzoic acid was analyzed in cultured MCF7 cells and in cellular homogenates. Glucuronidation and sulfoconjugation were studied in MCF7 homogenates, and parabens were analyzed by HPLC. Methyl-paraben was shown to be far less toxic than butyl and benzyl-paraben. Parabens were completely stable in MCF7 homogenates whereas p-nitrophenyl acetate, a substrate type, underwent hydrolysis. MCF7 cell homogenates did not express glucuronidation and sulfoconjugation activities toward parabens. The higher stability of parabens may explain their accumulation in breast cancer tissue as previously reported in the literature.