Fig. 5

Paqr8 promotes ER+ breast cancer cell survival following E2 pathway inhibition. A Representative images of MCF7 colony formation assays performed in growth medium (+ PhR FBS), E2-deprived medium (–PhR csFBS), or E2-deprived medium supplemented with 1 nM E2 (–PhR csFBS + E2). Proportion of cells plated that formed colonies in –PhR csFBS (B) or –PhR csFBS + E2 medium (C), normalized to + PhR FBS medium. D Viable cell count of BT474-M1 cells in –PhR csFBS or –PhR csFBS + E2 medium, normalized to + PhR FBS medium. E Representative images of MCF7 colony formation assays performed in the presence of increasing concentrations of fulvestrant or vehicle control (DMSO), and quantification (F). G Representative images of immunofluorescence staining for cleaved caspase-3 (cc3) in –PhR csFBS or + PhR FBS medium, and quantification (H). I Percentage of eGFP+ cells that were EdU+ or Ki67+ following 2 h of 10 mM EdU labeling. (J) Time to first palpation of MCF7 tumors forming in NSG mice without E2 pellet supplementation. K Representative cc3 staining in primary tumor tissue sections, and quantification (L). Sections were also stained for EdU and Ki67, and the percentages of eGFP+ cells that were EdU+ or Ki67+ were quantified (M)