Cytotoxic responses to unfractionated extracts from digestive glands of mussels

The contamination of bivalve molluscs by lipophylic toxins is mainly detected by the use of unfractionated extracts from contaminated material in mouse bioassays. The development of alternate detection methods based on the use of cultured cells is hampered by difficulties related to the complexity of matrices including toxic compounds obtained from contaminated material. In this paper we have used unfractionated lipid extracts prepared from the digestive gland of mussels, which gave a negative response by the mouse bioassay, and have investigated their effects on functioning of MCF-7 cells. We show that altered growth was induced after addition of lipid extracts corresponding to less than 1mg of digestive gland per ml of culture medium. The cytotoxic effect was also confirmed by the analysis of the effect of the unfractionated extracts on four selected proteins, which were used as markers of general (actin), regulatory (mitogen activated protein kinase isoforms ERK1 and ERK2), as well as differentiative (alpha isoform of estrogen receptor) functions of the MCF-7 human breast cancer cell line.