Figure 2
Plumbagin suppresses CXCR4 expression in breast cancer cells. A, Plumbagin suppresses CXCR4 levels in a dose-dependent manner. MDA-MB-231 cells (1 × 106) were treated with the indicated concentrations of plumbagin for 6 h. Whole-cell extracts were then prepared, and 30 μg of protein was resolved on SDS-PAGE, electrotransferred onto nitrocellulose membranes, and probed for CXCR4. The same blots were stripped and reprobed with β-actin antibody to show equal protein loading. B, Plumbagin suppresses CXCR4 levels in a time-dependent manner. MDA-MB-231 cells (1 × 106) were treated with 5 μM plumbagin for the indicated times, after which Western blotting was done as described above. The same blots were stripped and reprobed with β-actin antibody to show equal protein loading. C, Plumbagin suppresses CXCR4 levels in HER2 overexpressing BT474 cells. BT474 cells (1 × 106) were treated with the indicated concentrations of plumbagin for 6 h. Whole-cell extracts were then prepared, and 30 μg of protein was resolved on SDS-PAGE, electro-transferred onto nitrocellulose membranes, and probed for CXCR4. The same blots were stripped and reprobed with β-actin antibody to show equal protein loading. D, Effect of plumbagin on HER2 expression in BT474 cells. BT474 cells (1 × 106) were treated with the indicated concentrations of plumbagin for 6 h, after which Western blotting for HER2 was done as described above. The same blots were stripped and reprobed with β-actin antibody to show equal protein loading. The representative results of three independent experiments are shown.