Horizontal Transfer of Tamoxifen Resistance in MCF-7 Cell Derivates: Proteome Study.

Using estrogen-dependent MCF-7 breast cancer cells and tamoxifen-resistant MCF-7/T subline we have shown that their co-cultivation lead to increase in tamoxifen resistance in the parent MCF-7 cells. The proteome analysis of MCF-7/T cells and new-generated resistant cells revealed 21 common proteins differently expressed in both the resistant cell lines, among them - 6 proteins were associated with the drug or hormonal resistance. Both resistant lines were characterized with suppression of estrogen receptor and activation of SNAIL1-signaling - mesenchymal pathway playing an important role in the down-regulation of estrogen receptor and maintaining of the estrogen-independent phenotype.