Effect of CHD5 on cell proliferation in breast cancer cell lines. (A) Confirmation of CHD5 expression in transfected MDA-MB-231 cells by Western blotting, with β-actin (ACTB) as a loading control. (B) Representative images of cells transfected with CHD5 or vector plasmid in six-well culture plates at 12 days of G418 selection. (C) Ectopic expression of CHD5 in MDA-MB-231 cells decreased colony formation efficiency at both 12 and 16 days of G418 selection, as detected by SRB staining. The numbers of cells are indicated by optical densities. (D, E) Ectopic expression of CHD5 increased the number of cells in the G0/G1 phase but decreased the number of cells in the S phase of the cell cycle, as determined by flow cytometer. Transfected cells were selected by G418, and pools A and B were a mixture of transfected MDA-MB-231 cells from two independent transfection and selection experiments. (F) Ectopic expression of CHD5 inhibits cell proliferation in Hs 578T cells, as measured by SRB staining assay. Parental cells without plasmid transfection (mock) and cells transfected with empty vector (vector control) and antisense CHD5 were used as negative controls. (G) Knockdown of CHD5 expression by siRNAs (Q7 and I20) inhibits the proliferation of T-47D cells as compared to parental cells (Mock) or siRNA control (Ctrl).