Figure 1

Transfection of rat HER2, ER and PgR genes into 4T1 cells produces a population of TNBC and TPBC. (A) Parental 4T1 cells (10⁶), TNBC (10⁶), or TPBC (10⁶) were placed on ice and stained with anti-ER-FITC (top panels) or anti-PgR-PE (bottom panels). The surface intensity for these antibodies were analyzed by flow cytometry using a FACSort with a Lysys II software program (Becton & Dickinson). Individual cells were gated based on forward (FSC) and orthogonal scatter (SSC). Cell debris was excluded by raising the FSC-height PMT threshold. Histograms are mean relative counts and are a representative experiment of three independently performed experiments with similar results. (B) Parental 4T1 cells (10⁶) (lane 1), TNBC (10⁶) (lane 2), or TPBC (10⁶) (lane 3) were lysed and the amount of ErbB2 (HER2) was determined by Western blot analysis using specific Mab as described in detail in the Materials and Methods section. β-actin was used as control for equal loading. The intensity of the bands were analyzed by densitometry with a video densitometer (Chemilmager™ 5500; Alpha Innotech, San Leandro, CA) using the AAB software (American Applied Biology). Data is a representative experiment from three independently performed experiments with similar results.