UC San Diego

There is currently no successful therapy available for prostate cancer that has progressed to the androgen- deprivation-resistant metastatic stage. It is believed that after androgen-deprivation ablation of the bulk of differentiated cells that make up the tumor, the hormone- deprivation resistant tumor regrows from a subpopulation of prostate epithelial cells. The role of these prostate tumor stem cells (PrTuSC) in neovascularization is of primary interest, due to the direct correlation of angiogenesis with metastasis. In vitro analyses examined the angiogenic potential of the PrTuSC cells isolated from early prostate tumors. These included an angiogenic antibody array assay of media conditioned by the cells to discover which angiogenic proteins they expressed. Proteins expressed at high levels in vitro were Tissue Inhibitor of Metalloproteinases (TIMP-1) and Interleukin-8 (Il-8). Next, the functional angiogenic properties of these proteins were verified by endothelial cell migration and proliferation assays. ELISA was done to quantify protein levels. Development of an in vivo methodology to study paracrine effects of TIMP-1 and Il-8 on neovascularization was undertaken. This methodology entails the implantation of alginate disks containing the cells and proteins of interest into the dorsal skin-fold window chamber of nude mice. The window chamber allows real time in vivo fluorescent microscopy of angiogenic response to the proteins. Both Il-8 and TIMP-1 promoted neovascularization in the window chamber