Tumor-associated macrophages (TAMs) exhibit an M2 macrophage phenotype that suppresses anti-tumor immune responses and often correlates with poor outcomes in patients with cancer. included induction of the M2 markers CD163 and CD206 and the immunosuppressive cytokines IL-10 and chemokine ligand 17 and down-regulation of the immunostimulatory cytokine IL-12. HOXA9-mediated induction of TAMs was primarily due to the combinatorial effects of HOXA9-induced tumor-derived transforming growth factor-β2 and chemokine ligand 2 Rabbit Polyclonal to ATG16L2. levels. High HOXA9 expression in clinical specimens of ovarian cancer was strongly associated with increased abundance of TAMs and intratumoral T-regulatory cells and decreased abundance of CD8+ tumor-infiltrating lymphocytes. Levels of immunosuppressive cytokines were also elevated in ascites fluid of patients with tumors that highly expressed HOXA9. HOXA9 may therefore stimulate ovarian cancer progression by promoting an immunosuppressive microenvironment via paracrine effects on peritoneal macrophages. It is increasingly recognized that tumor progression is controlled by the dynamic interplay between tumor and stromal cells such as fibroblasts endothelial cells and immune cells.1 2 TC-E 5001 Among the latter macrophages are a major component. Macrophages exhibit diverse functional properties in response to different microenvironmental cues. Two polarized macrophage phenotypes have been described that are analogous to the type 1/2 helper T-cell dichotomy of T-cell responses. On one hand macrophages that are stimulated with microbial agents and interferon-γ exhibit an M1 (classically activated) phenotype and express immunostimulatory cytokines.3 4 On the other hand stimulation of macrophages with IL-4 IL-10 or IL-13 induces an M2 (alternatively activated) phenotype.3 4 M2 macrophages are often characterized by expression of mannose and scavenger receptors and of immunosuppressive cytokines and chemokines. One important mechanism by which these macrophage-derived factors suppress anti-tumor immunity is by stimulating recruitment of T-regulatory (Treg) cells.3 4 Tumor-associated macrophages (TAMs) derive from circulating monocyte precursors and are recruited to tumors. TAMs are widely thought to exhibit an M2 macrophage phenotype and are strongly associated with poor outcomes in patients with a wide variety of cancers.5 However it is unclear whether tissue-specific mechanisms in a particular type of cancer regulate the interaction between tumor cells and macrophages in the tumor microenvironment. Approximately 75% of patients with epithelial ovarian cancer present with disease that has already TC-E 5001 disseminated throughout the peritoneal cavity at the time of initial diagnosis.6 7 Ovarian cancer cells typically spread by exfoliating into the peritoneal fluid and implant TC-E 5001 on the omentum and other peritoneal surfaces.6 7 Peritoneal carcinomatosis is frequently TC-E 5001 associated with the formation of ascites. The peritoneal cavity normally harbors na?ve macrophages that play essential roles in regulating tissue repair and inflammatory responses. Ovarian cancer cells have been demonstrated to polarize macrophages toward an M2 phenotype 8 9 but the molecular mechanisms in ovarian cancer cells that induce this polarization are poorly understood. Because of the unique clinical behavior of ovarian cancer we hypothesized that interactions between ovarian cancer cells and peritoneal macrophages might be controlled in part by tissue-specific mechanisms that are activated in ovarian cancer cells. Homeobox genes encode transcription factors that control self-renewal and cell differentiation.10 11 The homeobox gene is normally expressed during development of the female reproductive tract and its expression is tightly regulated in the adult tract.12 13 We recently identified that high expression in ovarian cancer is strongly associated with poor overall survival and that promotes ovarian tumor growth but not genes and SKOV3ip cell lines that stably express shRNAs have been previously described.13 14 MOSEC and SKOV3ip cell TC-E 5001 lines were cultured in Dulbecco’s modified Eagle’s medium and McCoy’s 5A medium (Invitrogen Carlsbad CA) respectively. The IC-21 mouse peritoneal macrophage cell line was purchased from ATCC (Manassas VA) and cultured in RPMI 1640 medium (Invitrogen). Normal peritoneal macrophages were.