Interleukin-17 promotes angiogenesis and tumor growth

Interleukin-17 (IL-17) is a CD4 T-cell-derived proinflammatory cytokine. We investigated the effects of locally produced IL-17 by tumors as a means to evaluate its biologic function. Although recombinant IL-17 protein or retroviral transduction of IL-17 gene into tumors did not affect in vitro proliferation, IL-17 transfectants grew more rapidly in vivo when compared with controls. Immunostaining for Factor VIII revealed that tumors transduced with IL-17 had significantly higher vascular density when compared with controls. IL-17 indeed elicited neovascularization in rat cornea. In addition, angiogenic activity present in the conditioned media of CD4 T cells was markedly suppressed by neutralizing monoclonal…