Effect of PELP1 knockdown on cell proliferation of ER-negative breast cancer cells. A, MDA-MB231 and 4T1 cells untransfected, and or stably expressing negative control (NC) shRNA vector or PELP1-shRNA were lysed and the expression of PELP1 was analyzed by real-time PCR analysis and Western blotting . B, Cell proliferation potential of the MDA-MB231 and 4T1 cells -PELP1-shRNA and control shRNA clones were measured in vitro by using a Cell Titer-Glo assay. Mean and SDs are from 3 independent experiments. *, p ≤ 0.05, t test.