The aim of this study was to assess paclitaxel resistant-epithelial ovarian carcinoma (EOC) cells for cellular morphology, motility, and molecular changes consistent with epithelial-mesenchymal transition (EMT). The human EOC cell lines NOS-2, TAOV and SKOV-3 were continuously exposed to increasing doses of paclitaxel to establish three stable cell lines resistant to paclitaxel (NOS-PR, TAOV-PR, and SKOV-PR cells, respectively). Using these cell lines, cellular functions such as motility, invasive ability, and proliferative potential were assessed. Several molecules involved in EMT or cell invasiveness were assessed using Western blot analysis. In a peritoneal metastasis model using mice inoculated with NOS-2 or NOS-PR cells, we investigated the differences of peritoneal dissemination and survival time. NOS2-PR cells showed phenotypic changes consistent with EMT; with spindle-shaped morphology and enhanced pseudopodia formation. Western blot analysis revealed decreased expression of the epithelial adhesion molecule, E-cadherin and an increase in mesenchymal markers such as vimentin, fibronectin and smooth-muscle actin in NOS-PR cells compared to NOS-2 cells. The NOS2-PR cells displayed increased expression of Snail and Twist, EMT-regulatory transcription factors. Migratory potential in a wound assay and metastatic potential to the peritoneum of mice were markedly enhanced in NOS2-PR cells compared to NOS-2 cells. These data suggest that there is a possible link between chronic paclitaxelresistance and induction of the EMT in EOC cells. It is possible that therapeutic benefits such as the restoration of chemosensitivity or suppression of metastasis will be enabled by gaining further insight into the mechanisms underlying chemoresistance and EMT.

Purpose: Angiotensin II is a bioactive peptide of the renin-angiotensin system, acting not only as a vasoconstrictor but also as a growth promoter via angiotensin II type 1 receptors (AT 1 R). The present study examined AT 1 R expression in human ovarian carcinoma and attempted to determine whether AT 1 R blocker could suppress the tumor progression. Experimental Design: Expression of AT 1 R, vascular endothelial growth factor (VEGF), and CD34 was immunohistochemically analyzed in ovarian tumor tissues (n = 99). Effects of AT 1 R blocker on invasive potential and VEGF secretion in ovarian cancer cells were examined in vitro. Effects of AT 1 R blocker in vivo were evaluated in a mouse model of peritoneal carcinomatosis. Results: AT 1 R was expressed in 57 of 67 (85%) invasive ovarian adenocarcinomas and 12 of 18 (66%) borderline malignant tumors but in only 2 of 14 (14%) benign cystadenomas. In invasive carcinomas,VEGF expression intensity and intratumor microvessel density were significantly higher in cases that were strongly positive for AT 1 R (n = 37) compared with those in cases weakly positive (n = 20) or negative (n = 10) for AT 1 R. Angiotensin II significantly enhanced the invasive potential and VEGF secretion in AT 1 R-positive SKOV-3 ovarian cancer cells, both of which were completely inhibited by the AT 1 R blocker candesartan. Administration of candesartan into SKOV-3-transplanted athymic mice resulted in the reduction of peritoneal dissemination, decreased ascitic VEGF concentration, and suppression of tumor angiogenesis. Conclusions: AT 1 R is functionally expressed in ovarian carcinoma and involved in tumor progression and angiogenesis. AT 1 R blockade therapy may become a novel and promising strategy for ovarian cancer treatment.

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolising enzyme inducing immune tolerance. The present study aimed to investigate IDO expression and its prognostic significance in endometrial cancer. Indoleamine 2,3-dioxygenase expression in endometrial cancer tissues (n ¼ 80) was immunohistochemically scored as four groups (IDOÀ, 1 þ , 2 þ , and 3 þ ). The high IDO expression (IDO2 þ or 3 þ ) in tumour cells was found in 37 (46.3%) of the 80 cases, and was positively correlated with surgical stage, myometrial invasion, lymph-vascular space involvement, and lymph node metastasis, but not with the histological grade. Patients with high IDO expression had significantly impaired overall survival and progression-free survival (PFS) (P ¼ 0.002 and P ¼ 0.001, respectively) compared to patients with no or weak expression of IDO (IDOÀ or 1 þ ). The 5-year PFS for IDOÀ/1 þ , 2 þ , and 3 þ were 97.7, 72.9, and 36.4%, respectively. Even in patients with early-stage disease (International Federation of Gynecology and Obstetrics I/II, n ¼ 64), the PFS for IDO2 þ /3 þ was significantly poor (P ¼ 0.001) compared to that for IDOÀ/1 þ . On multivariate analysis, IDO expression was an independent prognostic factor for PFS (P ¼ 0.020). These results indicated that the high IDO expression was involved in the progression of endometrial cancer and correlated with the impaired clinical outcome, suggesting that IDO is a novel and reliable prognostic indicator for endometrial cancer.

Purpose: Tumor escape from host immune systems is a crucial mechanism for disease progression. We recently showed that the immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) is a prognostic indicator for endometrial cancer. The purpose of the present study was to investigate the relationship between IDO expression and tumor-infiltrating lymphocytes (TIL) or natural killer (NK) cells and to clarify their prognostic effect in endometrial cancer. Experimental Design: Immunohistochemical staining for IDO expression in endometrial cancer tissues (n = 65) was done. Tumor-infiltrating CD3+ and CD8+ lymphocytes, as well as CD57+ NK cells, were counted in serial tissue sections. Results: High IDO expression in tumor cells was found in 32 of 65 cases and was positively correlated with myometrial invasion, nodal metastasis, and lymph-vascular space involvement. We also found a significant correlation between high IDO expression and reduced numbers of CD3+, CD8+, and CD57+ cells infiltrating into both the tumor epithelium and stroma. Patients with high IDO expression, a low number of stromal CD3 (<60), low intraepithelial CD8 (<25), or low stromal CD8 (<40) had significantly impaired progression-free survival. On multivariate analysis, IDO expression and the number of stromal CD3+ TILs were independent prognostic factors for impaired progression-free survival. Conclusions: Tumoral IDO expression correlated with a reduced number of TILs and NK cells in endometrial cancer, possibly contributing to disease progression and impaired clinical outcome. These findings suggest that targeting IDO to restore host antitumor immunity may be a therapeutic strategy for endometrial cancer.Tumor escape from host immune surveillance creates a state of ''tolerance'' and is a crucial mechanism for cancer progression (1). However, its underlying cellular and molecular basis remains poorly understood. Recent studies suggest that one mechanism that may contribute to this tolerance is the immunoregulatory enzyme indoleamine 2,3-dioxygenase (IDO; ref. 2).IDO is an intracellular enzyme that catalyzes the initial and rate-limiting steps in the metabolism of the essential amino acid tryptophan along the kynurenine pathway (3). Recently, evidence that indicates an immunosuppressive function for IDO has been accumulating. It was first found that IDO is expressed in the mouse placenta during pregnancy and prevents rejection of the allogeneic fetus, thereby suggesting involvement of IDO in fetal-maternal tolerance (4). Subsequent studies clarified the mechanism of IDO immunosuppression to be local depletion of tryptophan and/or production of toxic tryptophan catabolites, causing growth arrest and the apoptosis of alloreactive T cells or natural killer (NK) cells that are extremely sensitive to tryptophan shortage (5). The tryptophan-derived catabolite kynurenine also inhibits the expression of specific triggering receptors on NK cells and regulates NK-cell function (6).In malignancy, it was firstly shown that IDO is expressed by the tumor...

Epithelial ovarian carcinoma (EOC) spreads by implantation of tumor cells onto the human peritoneal mesothelial cells (HPMCs) lining the peritoneal cavity. The aim of this study was to determine whether the stromal cell-derived factor-1a (SDF-1a)/CXCR4 axis is involved in the interaction of EOC cells with HPMCs in peritoneal metastasis. Clinically, we first evaluated CXCR4 expression in sections from 36 primary EOCs using immunohistochemistry. We next examined whether SDF-1a played roles in EOC progression, including in proliferation, cell motility, attachment to HPMCs, and the in vivo development of peritoneal metastasis through CXCR4. Of the 36 carcinomas, 16 cases (44.4%) were positive for CXCR4 immunoexpression. Positive CXCR4 expression significantly predicted poorer overall survival compared with negative expression (p 5 0.0069). We found CXCR4 expression in both EOC cells and HPMCs. In contrast, the level of production of SDF-1a by HPMCs was higher than that by various EOC cells. Functionally, SDF-1a induced enhanced attachment between ES-2 cells and HPMCs or extracellular matrix components. The enhancement of adhesion potential by SDF-1a was inhibited by AMD3100, a CXCR4 antagonist, and by phosphatidylinositol 3 kinase and p44/42 inhibitors. Furthermore, intraperitoneal treatment with AMD3100 resulted in reduced dissemination in nude mice inoculated with ES-2 cells. The present results suggest that there may be a link between the SDF-1a/CXCR4 axis and enhanced intraperitoneal dissemination of EOC and that CXCR4 may be a novel target for the treatment of EOC. ' 2007 Wiley-Liss, Inc.