RNA-seq of two human mammary epithelial cell lines (HMLE and HMLE-Twist-ER) treated with 4-hydroxytamoxifen vs control

Immortalized non-cancerous human mammary epithelial cells (HMLE) were transfected to express the murine fusion protein Twist1-estrogen receptor(point mutation G525R) (HTER). Twist1-mediated gene expression is activated by stimulation with 4-hydroxytamoxifen for several days and induces an epithelial-mesenchymal transition (EMT) in HTER cells. In breast cancer, EMT equips cancer cells for metastasis and therapy resistance. As control, HTER cells were treated with vehicle (methanol). As additional controls, HMLE cells were stimulated with 4-hydroxytamoxifen or methanol, respectively. Prior to RNA sequencing, EMT-undergoing HTER cells were sorted by fluorescence-activated cell sorting (FACS) based on E-Cadherin and CD44 surface protein levels into three populations, epithelial (E), hybrid epithelial-mesenchymal (EM), and mesenchymal (M): E-Cadherin_high_CD44_low (E), E-Cadherin_medium_CD44_medium (EM), and E-Cadherin_low_CD44_high (M).