Growth of hormone-dependent MCF-7 breast cancer cells is promoted by constitutive caveolin-1 whose expression is lost in an EGF-R-mediated manner during development of tamoxifen resistance.

Caveolin-1 displays both tumour-suppressor and tumour-promoter properties in breast cancer. Using characterised preclinical cell models for the transition of oestrogen-sensitive (WT-MCF-7 cells) to a tamoxifen-resistant (TAM-R cells) phenotype we examined the role caveolin-1 in the development of hormone-resistant breast cancer. The WT-MCF-7 cells showed abundant expression of caveolin-1 which potentiated oestrogen-receptor (ERalpha) signalling and promoted cell growth despite caveolin-1 mediating inhibition of ERK signalling.