Figure 4

K-Ras activity in response to CXCL12 exposure. a) Pancreatic cancer cells were serum-starved and then exposed to CXCL12 (100 ng/ml) and CXCL11 (200 ng/ml) for 15 min. Whole cell lysates were assessed for K-Ras activity using a Raf pull-down assay. b) Cells were transfected with control, CXCR4, or CXCR7 siRNA (100 nM). Following serum-starvation cells were treated with CXCL12 (100 ng/ml) for 15 min. K-Ras activity was normalized to each untreated baseline level; and relative increases are depicted. The mean absorbance ± one SD was plotted for each treatment group. * designates p < 0.05.