Figure 4. Knockdown of EpoR expression inhibits cell migration and invasion potential of SKBR3 cells. (A) Five lentiviral constructs containing different EpoR-targeting sequences were used to transduce SKBR3 cells as described in Materials and Methods. After the transduction, the cells were harvested for detection of the efficiency of EpoR knockdown by western blotting. The level of β-actin was used for protein loading control. (B) Parental SKBR3 cells and SKBR3 cells transduced with lentivirus containing control vector or EpoR shRNA (#1 or #4) were added into the upper wells of transwell chambers at 6 × 10⁴ cells in 150 μL. The bottom wells were filled with 700 μL regular cell culture medium. The transwell chambers were placed in a 37 °C incubator filled with 5% CO₂ and 95% air; 24 h later, the number of cells passed through the membrane in the transwell was analyzed. (C) SKBR3 cells transduced with lentivirus containing control shRNA vector or EpoR shRNA (construct #1 or #4) were subjected to a scratch wood healing assay as described in Materials and Methods.