Fig. 5.

GSE inhibits HIF-1α expression in tumor. (A) GSE inhibited HIF-1α expression and phosphorylation of S6K and S6 ribosome proteins in tumors implanted in the mice. Tumor tissue lysates were analyzed by immunoblotting for the expression of HIF-1α and phosphorylation of S6K and S6 proteins. β-tubulin was used as loading control. (B) GSE treatment had little effect on HIF-1α localization in tumor by immunohistochemistry. MDA-MB-231 tumor sections were stained with antibody against HIF-1α. Bar, 20 μM. (C and D) Effect of MDA-MB-231-conditioned medium (C) and U251-conditioned medium (D) on endothelial cell migration. Human umbilical vascular endothelial cells were placed in the top chamber of a transwell, whereas serum-free medium containing various amount of tumor-conditioned medium was placed in the bottom of chamber. Migrated cells were quantified 5 h after incubation under ×40 objective. Data were expressed as number of migrated cells per high power field (HPF). *P < 0.05 versus control treated with water alone.