CXCR7 depletion in MCF7 cells affects breast cancer cell proliferation. A. The clonogenic potential of CXCR7 depleted MCF7 cells was analyzed in colony forming assays. The insert shows colony formation in CXCR7 depleted (stably shCXCR7 (shr7) transfected cells, right well) compared to vector control transfected cells (shC) (left well). B. Cell proliferation of MCF7 cells with stable CXCR7 depletion (shCXCR7 clone, (shR7)) compared to control cells (shC). C. Effect of CXCR7- (siR7) and CXCR4- (siR4) down regulation and CXCR7 (R7) over expression on proliferation of MCF7 cells. D. Proliferation of CXCR7 depleted (siR7) BT474 cells and CXCR7 over expressing (R7) MB231 cells compared to corresponding controls (siC = control siRNA, C = empty plasmid control). E. Cell cycle arrest of cells with down regulated CXCR7. F. Analysis of relevant cell cycle markers following siRNA mediated down regulation of CXCR7. Asterisks indicate statistical significance, P < 0.05.