Figure 1

The effect of HER-2 and oestrogen receptor (ER) expressions on the growth response of breast tumour cell lines expressing aromatase to various endocrine agents. (A) Breast tumour cell lines with varying ER and HER2 expression levels, transduced to express aromatase (CYP 19) (A) or the back bone vector (neo), were treated with escalating concentrations of androstenedione. After 6 days of treatment, the cell number was established using a coulter counter. Data are expressed as fold change compared with vehicle control. (B) The breast tumour cell lines were treated with log₁₀(M) increasing concentrations of 4-OH tamoxifen in the presence of 10 nM androstenedione. (C) Cells were treated with log₁₀(M) increasing concentrations of letrozole in combination with a standard 10 nM concentration of androstenedione. (D) Breast tumour cell lines were treated with increasing concentrations of AEE788 in combination with a standard concentration of androstenedione (10 nM). Bars represent±s.e.m. The data are representative of five individual experiments.