Fig 1: Biomarkers of the undifferentiated/IRES-active and differentiated/IRES-off phenotypes. (A) T47D cells were treated with IRES inhibitor cpd_W as described in Fig. 2. At the 48 h time-point, the cells were fixed and stained for ERα (D8H8) and RACK1. (B) T47D cells were treated with cpd_W for 15, 24 or 48 h. Exposure to cpd_W was terminated by replacing with fresh media and cells were fixed and stained for ERα and RACK1 at the 48 h time-point. (C) ZR-75-1 cells were treated and stained for ERα and RACK1 as abovedescribed in (A). (D-J) T47D (D, F, H and J) or ZR-75-1 (E, G and I) cells were treated with cpd_W or vehicle control for 48 h, then stained for IGF1R N20 and GRP78 (D and E), RACK1 and ZO-1 (F and G), RACK1 and CLIMP-63 (H), ERα and E-cadherin (I), or IGF1R N20 and α-tubulin (J).