Figure 4: ESR1–CCDC170 endows more aggressive phenotypes in T47D ER+ breast cancer cells.

Ectopic expression of ΔCCDC170 in T47D cells results in a significant increase in (a) cell motility, (b) anchorage-independent growth and (c) colony-forming ability. (d) Time-point changes in the proliferation of fusion-expressing T47D cells after tamoxifen treatment (4-OHT). (e) Surviving fraction of T47D cells expressing ΔCCDC170 after 7 days of 4-OHT. In assay d,e, T47D cells are deprived of oestrogen for tamoxifen treatment. Error bars represent the standard deviation of two replicate measurements per condition and results shown are representative of experiments performed at least twice. (f) The growth curve of xenograft tumours expressing vector, E2–E7 or E2–E10 ΔCCDC170 variants engrafted bilaterally in athymic nude mice (8 mice per group). Tumour volumes of deceased mice are not included after the day of death. Day 1 represents the first tumour measurement 7 days post tumour cell implantation. Data are presented as mean±s.d. of indicated sample size. (g) Boxplots comparing the Ki67 scores in available xenograft tumour tissues expressing vector (n=12), E2–E7 (n=14) or E2–E10 (n=14). ‘Vector’ indicates the pLenti7.3 vector control containing an YFP ORF. *P<0.05, **P<0.01, ***P<0.001 (the P-value for Fig. 4f is based on analysis of variance, and others are all based on t-test).