Figure 1

Endothelial cell-derived factors phosphorylate STAT3, Akt, and ERK in tumor cells in vitro and in vivo . A, western blot for phosphorylated and total STAT3, Akt, and ERK in HeLa serum-starved overnight and exposed to HDMEC conditioned medium (CM), HeLa CM, or control unconditioned medium (EBM) for the indicated time points. B, western blot for phosphorylated and total STAT3, Akt, and ERK in HeLa or HOK-16B serum-starved overnight and exposed to HDMEC CM or EBM for the indicated time points. C, immunohistochemical analysis for phosphorylated STAT3, Akt, and ERK (with nuclear localization) in representative specimens from xenograft human squamous cell carcinomas. Top panels represent 100× and lower panels represent 200× magnification. Red arrows point to blood vessels.