This study explored the role of secreted fibroblast-derived factors in prostate cancer growth. Analyses of matched normal and tumor tissue revealed up-regulation of CXCL14 in cancer-associated fibroblasts of a majority of prostate cancer. Fibroblasts overexpressing CXCL14 promoted the growth of prostate cancer xenografts, and increased tumor angiogenesis and macrophage infiltration. Mechanistic studies demonstrated that autocrine CXCL14-stimulation of fibroblasts stimulate migration and ERKdependent proliferation of fibroblasts. CXCL14-stimulation of monocyte migration was also demonstrated. Furthermore, CXCL14-producing fibroblasts, but not recombinant CXCL14, enhanced in vitro proliferation and migration of prostate cancer cells and in vivo angiogenesis. These studies thus identify CXCL14 as a novel autocrine stimulator of fibroblast growth and migration, with multi-modal tumor-stimulatory activities. In more general terms, our findings suggest autocrine stimulation of fibroblasts as a previously unrecognized mechanism for chemokine-mediated stimulation of tumor growth, and suggest a novel mechanism whereby cancer-associated fibroblasts achieve their pro-tumorigenic phenotype.cancer-associated fibroblasts ͉ prostate cancer ͉ tumor stroma

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Platelet-derived growth factor (PDGF) receptor signaling is a major functional determinant of cancerassociated fibroblasts (CAF). Elevated expression of PDGF receptors on stromal CAFs is associated with metastasis and poor prognosis, but mechanism(s) that underlie these connections are not understood. Here, we report the identification of the secreted glycoprotein stanniocalcin-1 (STC1) as a mediator of metastasis by PDGF receptor function in the setting of colorectal cancer. PDGF-stimulated fibroblasts increased migration and invasion of cocultured colorectal cancer cells in an STC1-dependent manner. Analyses of human colorectal cancers revealed significant associations between stromal PDGF receptor and STC1 expression. In an orthotopic mouse model of colorectal cancer, tumors formed in the presence of STC1-deficient fibroblasts displayed reduced intravasation of tumor cells along with fewer and smaller distant metastases formed. Our results reveal a mechanistic basis for understanding the contribution of PDGF-activated CAFs to cancer metastasis. Cancer Res; 73(4);