Removal of Serum Lipids and Lipid-Derived Metabolites to Investigate Breast Cancer Cell Biology

The use of cultured cells has been instrumental in studying biochemical, molecular, and cellular processes. The composition of serum that cells are maintained in can have a profound impact on important cellular checkpoints. Cell growth and apoptosis are analyzed in an estrogen receptor positive breast cancer cell line in the presence of serum that have been treated to remove steroids or lipids, as well-described in the literature. It is shown that maintaining cells in the presence of charcoal-dextran-treated serum causes reduced growth rate, which can be reversed by the addition of estradiol. Silica-treated-serum also slows down cell growth and induces apoptosis. In order to investigate the role of lipids in these phenotypes, the levels of a wide range of lipids in different sera are investigated. It is shown that silica-treatment significantly depletes phosphatidylcholines and cholesterol. It is also shown that lipogenesis is stimulated when cells are cultured with silica-treated-serum and this is reversed by the addition of exogenous lipids, which also restores growth rate and apoptosis. The results show that cultured cells are sensitive to different serum, most likely due to the differences in levels of structural and signaling metabolites present in their growth environment.