IL-6 is linked with the induction of angiogenesis.

A. The level of IL-6 in cell culture supernatants and serum of mice bearing tumors with or without the IL-6 silencing vector was examined by ELISA in vitro and in vivo. Column, mean of three separate experiments. Bars, SD. *, P<0.05. B. Change in vascular endothelial growth factor (VEGF) and matrix metallopeptidase 9 (MMP-9), and CD31 in tumor xenografts was evaluated by immunohistochemical staining. The results from representative slides are shown. C. Effect of IL-6 on xenograft tumor growth and the induction of angiogenesis was evaluated in mice bearing tumors for 2 weeks. Tumor cells were injected subcutaneously into the mice with or without IL-6 injection as indicated in Materials and Methods, and tumor growth examined 2 weeks later. Immunohistochemistry using MMP-9, CD31, and VEGF stained- representative slides were demonstrated.