Fig. 3

ESR1 mutant-cells display resistance against selective estrogen receptor modulators (SERMs) and selective estrogen receptor degraders (SERDs). Graphical (a) and tabular (b) presentation of half maximal inhibitory concentration (IC50) values that were determined in dose–response curves in wild-type (WT), Y537S and D538G cells treated with 20 pM estradiol (E2) plus varying doses of 4OHT, raloxifene (Ral), fulvestrant (Ful), and AZD9496 in T47D and MCF7 cell lines. One-way analysis of variance was performed to compare the IC50 values of mutants to WT within each cell line and drug (*p < 0.05, **p < 0.01). Each dot is representative of the mean of a single experiment with six biological replicates. The experiments were performed six times (T47D) or eight times (MCF-7). c Pooled T47D-WT and T47D-D538G cells were mixed at a ratio of 99:1 and grown in 10% FBS, 10% CSS, 10% CSS + 1 nM E2 + 100 nM 4OHT, or 10% CSS + 1 nM E2 + 30 nM fulvestrant. The mutation allele frequency was analyzed at each passage using digital droplet PCR