Perinatal outcomes of abnormal umbilical coiling according to a modified umbilical coiling index.

AIM: The aim of this study was to determine the relation between perinatal outcomes and umbilical cord coiling as evaluated by a modified umbilical coiling index. METHODS: In this retrospective study, 200 consecutive umbilical cords were examined. An umbilical venous and arterial coiling index was calculated by dividing the total number of umbilical venous and arterial coils by the length of cord individually. Umbilical cords with umbilical venous coiling indices in the lowest decile, the highest decile, and the remaining deciles were defined as hypocoiled, hypercoiled, and normocoiled, respectively. The perinatal outcomes of the subjects with hypocoiled and hypercoiled umbilical cords were compared with those with normocoiled umbilical cords. RESULTS: In 69.5% of subjects, a difference in the degree of coiling was detected between the umbilical veins and arteries. While all umbilical venous twisting demonstrated the same direction, the direction of the arterial twisting reversed at a certain point along the umbilical cord in 19.0% of the subjects. The arteriovenous coiling difference was small in the hypercoiled group and large in the hypocoiled group. A hypocoiled umbilical cord evaluated by umbilical venous coiling index was found to be associated with prolonged deceleration (odds ratio [OR], 4.18; 95% confidence interval [CI], 1.54-11.38), operative delivery (OR, 2.67; 95%CI, 1.01-7.09), and nuchal cord entanglement (OR, 3.21; 95%CI, 1.23-8.33). CONCLUSION: Umbilical coiling abnormalities were investigated using a novel umbilical venous coiling index. A hypocoiled umbilical cord evaluated by umbilical venous coiling index was found to be associated with fetal heart rate abnormalities, operative delivery, and nuchal cord entanglement.

The risk factors for labor onset hypertension.

Our aim was to clarify the perinatal outcomes of and risk factors for hypertension that is first detected after labor onset (labor onset hypertension, LOH), which may be a risk factor for eclampsia and stroke during labor. A total of 1349 parturient women who did not exhibit preeclampsia or gestational hypertension prior to labor were examined. The patients were classified into four groups: the normotensive (n=1023) (whose systolic blood pressure (SBP) remained below 140 mm Hg throughout labor), mild LOH (n=241) (whose maximum SBP during labor ranged from 140 to 159 mm Hg), severe LOH (n=66) (whose maximum SBP during labor ranged from 160 to 179 mm Hg) and emergent LOH groups (n=19) (whose maximum SBP during labor was greater than 180 mm Hg). The perinatal outcomes and patient characteristics of the four groups were compared. Twenty-four percent of the pregnant women who remained normotensive throughout pregnancy developed hypertension during labor. One of the patients in the emergent LOH group developed eclampsia. The blood pressure at delivery and frequencies of hypotensor use, interventional delivery and low Apgar scores differed significantly among the four groups. The following risk factors for severe/emergent LOH were extracted: being over 35 years old, a body mass index at delivery of >30, an SBP at 36 weeks' gestation of 130-134 mm Hg, an SBP at admission of 130-139 mm Hg, proteinuria (a score of 2+ on the dipstick test) and severe edema. The risk factors for severe/emergent LOH were identified in this study. In high risk cases, repeatedly measuring maternal blood pressure during delivery might help detect critical hypertension early.

Identification and characterization of cancer stem cells in ovarian yolk sac tumors.

Recent evidence supports the cancer stem cell theory, that is, that malignant tumors arise from cells termed cancer stem cells or tumor-initiating cells that have the ability to self-renew and are responsible for maintaining the tumor. Cells with marked tumor-initiating capacity have recently been identified in a number of solid tumors. CD133 (PROM1, human prominin-1) has been used as a marker to detect stem cells (progenitor cells) and cancer stem cells (tumor-initiating cells) in various tissues. Ovarian yolk sac tumors (YSTs) are rare and highly malignant. The present study was designed to evaluate the tumor-forming ability of CD133(+) cells in ovarian YST cell lines and to examine the characteristics of CD133(+) cells, such as cell growth and invasiveness. Our data suggest ovarian YST to be maintained by a rare fraction of cancer stem-like cells that express the cell surface marker CD133.

Overexpression of indoleamine 2,3-dioxygenase in human endometrial carcinoma cells induces rapid tumor growth in a mouse xenograft model.

PURPOSE: Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolizing enzyme that induces immune tolerance in mice. Our prior study showed that high tumoral IDO expression in endometrial cancer tissues correlates with disease progression and impaired patient survival. The purpose of the present study was to clarify the functional role of IDO in human endometrial cancer cells and to investigate the therapeutic potential of IDO inhibitors. EXPERIMENTAL DESIGN: IDO cDNA was transfected into the human endometrial carcinoma cell line AMEC, resulting in the establishment of stable clones of IDO-overexpressing AMEC cells (AMEC-IDO). AMEC-IDO cells were characterized in vitro as well as in vivo using a mouse xenograft model. RESULTS: There was no significant difference in in vitro cell proliferation, migration, or chemosensitivity to paclitaxel between AMEC-IDO and control vector-transfected cells (AMEC-pcDNA). However, in vivo tumor growth was markedly enhanced in AMEC-IDO-xenografted nude mice when compared with AMEC-pcDNA-xenografted mice. Splenic natural killer (NK) cell counts in AMEC-IDO-xenografted mice were significantly decreased when compared with control mice. Furthermore, conditioned medium obtained from AMEC-IDO cell cultures markedly reduced the NK lysis activity of nude mice. Finally, oral administration of the IDO inhibitor 1-methyl-D-tryptophan in combination with paclitaxel in AMEC-IDO-xenografted mice strongly potentiated the antitumor effect of paclitaxel, resulting in significantly prolonged survival. CONCLUSIONS: This is the first evidence showing that IDO overexpression in human cancer cells contributes to tumor progression in vivo with suppression of NK cells. Our data suggest that targeting IDO may be a novel therapeutic strategy for endometrial cancer.

Long-term outcome and prognostic factors for yolk sac tumor of the ovary.

Yolk sac tumors of the ovary (YST) are rare and highly malignant tumors occurring in children and young adults. Because of its rarity, YST prognostic factors remain unclear. Our purpose was to evaluate the prognostic factors in YST. We performed a retrospective review of 36 patients with pure YST from 1986 to 2006. The 5-year overall survival and progression-free survival were 66.6% and 68.8%, respectively. Patients with stage I-II disease had a more favorable prognosis than those with stage III-IV (p < 0.05). Those with an ascites volume of less than 100 ml or a residual tumor measuring less than 1 cm had improved to a relatively good prognosis. Neither serum AFP level nor age had any significant correlation with the prognosis in this study. In conclusion, the FIGO (International Federation of Gynecology and Obstetrics) stage, ascites volume and residual tumor size tended to affect the prognosis of YST.

Feasibility and effectiveness of postoperative adjuvant concurrent chemoradiation therapy in Japanese patients with high-risk early-stage cancer of the uterine cervix.

BACKGROUND: This study was undertaken to evaluate the feasibility and effectiveness of postoperative concurrent chemoradiation (CCRT) in patients with high-risk early-stage cervical cancer who were treated by radical hysterectomy and pelvic lymphadenectomy. METHODS: From July 2001 to September 2005, CCRT was performed in 37 patients who had undergone radical hysterectomy with pelvic lymph node dissection at Nagoya University Hospital. Adjuvant chemotherapy consisted of cisplatin (70 mg/m(2) on day 1) and 5-fluorouracil (5-FU; 700 mg/m(2) per day on days 1-4) every 4 weeks for a total of three cycles. Pelvic radiotherapy was started concurrently with the first cycle of chemotherapy. The radiation dose was 45 Gy in 25 fractions. A nonrandomized control group of 52 patients who had undergone radiation therapy alone after radical hysterectomy between 1991 and 2000 served for historical comparison. RESULTS: In the CCRT group, the incidences of grade 3/4 toxicities were 24.3% for neutropenia, 8.1% for nausea and vomiting, and 18.9% for diarrhea. The 5-year progression-free survival (PFS) rates in the CCRT group and control group were 89.2% and 69.2%, respectively (P = 0.0392). CONCLUSION: This study showed that adjuvant CCRT with cisplatin and 5-FU could be safely performed and improved the prognosis in Japanese patients with high-risk early-stage cervical cancer after radical hysterectomy.

Establishment and characterization of an ovarian yolk sac tumor cell line reveals possible involvement of Nkx2.5 in tumor development.

OBJECTIVE: Ovarian yolk sac tumor (YST) is rare and highly malignant. Up to the present, there have been no cell lines of human ovarian YST constructed and, therefore, no studies on their cell function. The purpose of this study was to establish a human ovarian YST cell line to be able to identify a target for novel molecular-based therapy. METHODS: A 28-year-old woman underwent right salpingo-oophorectomy for right ovarian YST. YST cell lines (NOY1 and NOY2) were established from surgical specimens, and NOY1 cells were characterized. We also transfected them with small interfering RNA (siRNA) oligonucleotides specific for human Nkx2.5 and investigated cell proliferation compared to control siRNA-transfected cells. RESULTS: The cell lines were successfully maintained both in culture and in nude mice. Histological examination showed that xenografted tumors were composed of cells in solid and glandular patterns of YST. These cells were positively immunostained for AFP. Nkx2.5 siRNA-transfected NOY1 cell viability decreased by 50% compared to that of control-siRNA-transfected cells. CONCLUSIONS: This is the first report of a cell line established from human YST. Analysis of this new cell line suggested that Nkx2.5 can be a new molecular target in the treatment of ovarian YST.

Inverse correlation between tumoral indoleamine 2,3-dioxygenase expression and tumor-infiltrating lymphocytes in endometrial cancer: its association with disease progression and survival.

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.

Aminopeptidase N (APN)/CD13 inhibitor, Ubenimex, enhances radiation sensitivity in human cervical cancer.

BACKGROUND: Radiotherapy can be used to treat all stages of cervical cancer. For improving local control via radiotherapy, it is important to use additional antitumor agents. Aminopeptidase N (APN)/CD13, a 150-kDa metalloproteinase, is a multifunctional cell surface aminopeptidase with ubiquitous expression. Recent studies have suggested that APN/CD13 plays an important role in tumor progression in several human malignancies. METHODS: We investigated whether the suppression of APN/CD13 using Ubenimex, an inhibitor of APN/CD13 activity, may affect tumor radiosensitivity in cervical cancer cells both in vitro and in vivo. Cell surface APN/CD13 activity in HeLa cells was calculated using alanine-p-nitroanilido as a substrate. For colony formation assays, single-dose radiation and/or Ubenimex were administered to each dish of HeLa cells, and these dishes were cultured for 14 days. Molecular changes of apoptosis were determined by Western blot. Apoptosis was evaluated by Annexin-V PI staining (flow cytometry analysis) and the Tunel method. Moreover, we investigated the effect of combining Ubenimex and low-dose radiation on tumor growth using nude mice. RESULTS: We demonstrated that Ubenimex enhanced the effectiveness of radiotherapy, acting as a radiosensitizer both in vitro and in vivo. In colony formation assays, a significant decline in clonogenic survival was observed in Ubenimex-treated cells. Mice treated with a combination of radiation and Ubenimex showed a significant prolongation of the tumor-doubling time compared with the control, Ubenimex, or radiation-alone groups. We also showed that ubenimex enhanced radiation-induced apoptosis in vitro and in vivo. CONCLUSION: Although further studies are needed, this report suggests that Ubeniemx acts as a radiosensitizer in cervical cancer treatment, and that the inhibition of APN/CD13 activity may represent a new approach for improving the therapeutic efficacy of radiotherapy for uterine cervical cancer.

Taxol resistance among the different histological subtypes of ovarian cancer may be associated with the expression of class III beta-tubulin.

The prognostic significance of histology has been well established in epithelial ovarian cancer (EOC). Clear cell and mucinous histologies are especially generally accepted to result in an adverse outcome because of their poor chemotherapy response. Previous reports suggested that class III beta-tubulin induced taxol resistance in association with a reduced effect on microtubule dynamic instability. Thus, this study aimed to evaluate class III beta-tubulin expression and examine whether the protein level of class III beta-tubulin was correlated with the histological difference in chemosensitivity. Class III beta-tubulin expression in EOC tissues (n = 80) was immunohistochemically scored into 4 groups (-, +/-, +, ++). High-level (+, ++) class III beta-tubulin expression was detected in 30 of 35 clear cell carcinomas, in 8 of 10 mucinous carcinomas, 5 of 11 endometrioid carcinomas, and 5 of 24 serous carcinomas. Nineteen patients were evaluable for response. In 5 responders, high-level class III beta-tubulin expression was not detected. On the other hand, it was detected in 10 of 14 nonresponders. In some ovarian cancer cell lines, we evaluated class III beta-tubulin expression by Western blot analysis. Class III beta-tubulin expression in nonserous carcinoma tended to be higher than that in serous carcinoma. Taxol-resistant SKOV cells showed high-level class III beta-tubulin expression compared with wild-type SKOV cells. Taxol sensitivity differing among histological subtypes in EOC is associated with the expression of class III beta-tubulin.

Involvement of SDF-1alpha/CXCR4 axis in the enhanced peritoneal metastasis of epithelial ovarian carcinoma.

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-1alpha (SDF-1alpha)/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-1alpha 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 = 0.0069). We found CXCR4 expression in both EOC cells and HPMCs. In contrast, the level of production of SDF-1alpha by HPMCs was higher than that by various EOC cells. Functionally, SDF-1alpha induced enhanced attachment between ES-2 cells and HPMCs or extracellular matrix components. The enhancement of adhesion potential by SDF-1alpha 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-1alpha/CXCR4 axis and enhanced intraperitoneal dissemination of EOC and that CXCR4 may be a novel target for the treatment of EOC.

Irradiation-induced epithelial-mesenchymal transition (EMT) related to invasive potential in endometrial carcinoma cells.

OBJECTIVE: Epithelial-mesenchymal transition (EMT) is a process whereby cells acquire molecular alterations that facilitate cell motility and invasion. In this study, we hypothesized that ionizing irradiation would cause endometrial carcinoma cells (HEC1A) to undergo an increase of motility related to EMT. METHODS: We investigated the effect of ionizing irradiation on HEC1A cell migration. Furthermore, we examined whether this enhanced invasiveness was associated with epithelial-mesenchymal transition (EMT) and Twist siRNA transfections effects in ionizing irradiation-induced HEC1A cell migratory capacity. RESULTS: Ionizing irradiation leads to HEC1A cell phenotypic changes with EMT: spindle-cell shape, loss of polarity, intercellular separation, and pseudopodia formation. Ionizing irradiation leads to a 2-fold increase in HEC1A cell migration. In immunofluorescence staining of HEC1A cell, the expression of Twist, an organizer of EMT, increased by ionizing irradiation. Additionally, the irradiation-induced HEC1A cell invasion was inhibited by Twist siRNA transfections. CONCLUSIONS: This report suggested that the inhibitory effect of cell invasion through targeting Twist may represent a new approach for improving the therapeutic strategy.

Inhibition of APN/CD13 leads to suppressed progressive potential in ovarian carcinoma cells.

BACKGROUND: Aminopeptidase N (APN/CD13), a 150-kDa metalloprotease, is a multifunctional cell surface aminopeptidase with ubiquitous expression. Recent studies have suggested that APN/CD13 plays an important role in tumor progression of several human malignancies. In the current study, we investigated the role of APN/CD13 in ovarian carcinoma (OVCA) progression. METHODS: We first examined the expression of APN/CD13 at the protein level in a variety of OVCA cell lines and tissues. We subsequently investigated whether there was a correlation between APN/CD13 expression and invasive potential of various OVCA cell lines. Moreover, we investigated the function of APN/CD13 in OVCA cells using bestatin, an APN/CD13 inhibitor, or transfection of siRNA for APN/CD13. RESULTS: We confirmed that APN/CD13 was expressed in OVCA tissues and cell lines to various extents. There was a positive correlation between APN/CD13 expression and migratory potential in various OVCA cell lines with accordingly enhanced secretion of endogenous MMP-2. Subsequently, we found a significant decrease in the proliferative and migratory abilities of OVCA cells after the addition of bestatin or the inhibition of APN/CD13 expression by siRNA. Furthermore, in an animal model, daily intraperitoneal administration of bestatin after inoculation of OVCA cells resulted in a decrease of peritoneal dissemination and in prolonged survival of nude mice. CONCLUSION: The current data indicate the possible involvement of APN/CD13 in the development of OVCA, and suggest that clinical use of bestatin may contribute to better prognosis for ovarian carcinoma patients.

Establishment of a new cell line of endometrioid carcinoma of the ovary and its chemosensitivity.

A new cell line (NOE) of human ovarian endometrioid carcinoma was established and characterized. The cell line showed a short spindle-shaped morphology and continued to grow for more than 4 months without contact inhibition. The doubling time was approximately 15.5 h at the 10th passage. The chromosome number was aneuploid. The IC50 values of paclitaxel, cisplatin and carboplatin were 26.4 ng/mL, 2.4 microg/mL and 32.5 microg/mL, respectively. The NOE cells expressed estrogen receptor alpha. In nude mice, we confirmed tumor formation of NOE cells. These results indicated that NOE cells showed similar chemosensitivity and properties to those of the original tumor and might be useful in basic studies on the diagnosis, treatment and etiology of ovarian tumors.

Chemoresistance to paclitaxel induces epithelial-mesenchymal transition and enhances metastatic potential for epithelial ovarian carcinoma cells.

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 paclitaxel-resistance 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.

Uterine smooth muscle cells increase invasive ability of endometrial carcinoma cells through tumor-stromal interaction.

The incidence of lymph node metastasis by endometrial carcinoma (EMCA) increases with the depth of myometrial invasion, and this depth of invasion has been found to have a major impact on the outcome. In the present study, we assessed the effect of tumor-stromal interactions on the invasive behavior of EMCA cells and examined the involvement of SDF-1alpha/CXCL12-CXCR4 in the interaction of EMCA cells and uterine smooth muscle cells (UtSMCs). We investigated whether SDF-1alpha/CXCL12 produced and secreted from UtSMCs induces EMCA cell migration by using 5 human EMCA cell lines such as AMEC and RL95 cells. The SDF-1alpha/CXCL12 concentration in conditioned medium (CM) of UtSMCs(was 4,120 +/- 530 pg/ml. Treatments with CM of UtSMCs and plated UtSMCs significantly induced both AMEC and RL95 cell migration. The induced cell migrations were significantly inhibited by CXCR4 mAb (12G5) and CXCR4 antagonist (AMD3100) pre-treatments. Treatments with UtSMCs CM to AMEC and RL95 cells stimulated Akt phosphorylation in a time-dependent manner. Pre-treatment of AMEC and RL95 cells with wortmannin as a PI3K inhibitor significantly inhibited UtSMCs CM-induced cell migration. The SDF-1alpha/CXCL12-CXCR4 chemokine axis between UtSMCs and EMCA played an important role in the muscular infiltration of endometrial cancer through activation of PI3K-Akt signaling pathway. Suppression of this pathway could be an effective target for the treatment of early uterine body cancer in particular.

Possible involvement of TWIST in enhanced peritoneal metastasis of epithelial ovarian carcinoma.

Loss of E-cadherin triggers peritoneal dissemination, leading to an adverse prognosis for most patients with epithelial ovarian carcinoma (EOC). Because TWIST mainly regulates the epithelial-to-mesenchymal transition and is one of the E-cadherin repressors, we investigated the possibility that TWIST expression affects peritoneal metastasis of EOC using siRNA technique. In the present study, we showed a correlation between TWIST expression and EOC cellular morphology. Furthermore, we demonstrated that the suppression of TWIST expression in EOC cells (HEY) alters the cellular morphology from a fibroblastic and motile phenotype to an epithelial phenotype, and inhibits the adhesion of these cells to mesothelial monolayers. To investigate the mechanism by which down-regulation of TWIST leads to inhibition of adhesion to mesothelial cells (MCs), expression of adhesion molecules (CD29, CD44 and CD54) were observed. Moreover, matrix metalloproteinase 2 and membrane type 1 matrix metalloproteinase, important markers associated with invasive and metastatic potential, were remarkably reduced. This findings suggests that reduced expression of TWIST suppresses the multistep process of peritoneal dissemination (detachment from the primary lesion, adhesion to MCs and invasion of MCs) and may be a potential therapeutic target for the treatment of this carcinoma.

Involvement of aminopeptidase N in enhanced chemosensitivity to paclitaxel in ovarian carcinoma in vitro and in vivo.

Aminopeptidase N (APN/CD13), a 150-kDa metalloproteinase, is a multifunctional cell surface aminopeptidase with ubiquitous expression. Recent studies have suggested that APN/CD13 plays an important role in tumor progression in several human malignancies. In the current study, we investigated the role of APN/CD13 in paclitaxel (PAC)-resistance of ovarian carcinoma (OVCA) cells. We first examined the correlation between APN/CD13 expression and IC50 values of PAC in a variety of OVCA cell lines. Next we investigated whether suppression of APN/CD13 using bestatin, an inhibitor of APN/CD13 activity or the siRNA technique influenced PAC-sensitivity in ES-2 cells, which highly express APN/CD13. Moreover, we investigated the effect of bestatin on peritoneal metastasis using nude mice. We found a negative correlation between APN/CD13 expression and chemosensitivity to PAC in various carcinoma cell lines. Subsequently, we found a significant increase in PAC-sensitivity of APN/CD13 expressing OVCA cells by suppression of this enzyme, using the addition of bestatin or the siRNA technique. Furthermore, in a peritoneal metastasis model using nude mice, combination treatment with PAC and bestatin caused a synergistic increase of survival time compared with PAC alone treatment. (mean survival time: 37.7 +/- 7.0 s and 27.1 +/- 6.6 days, respectively). The present findings showed that APN/CD13 may be involved in decreased sensitivity to PAC in OVCA cells and that the mechanism of this effect involves its enzyme activity at least in part. APN/CD13 may be a therapeutic target for the treatment of OVCA in combination with chemotherapy.

Involvement of DPPIV/CD26 in epithelial morphology and suppressed invasive ability in ovarian carcinoma cells.

Dipeptidyl peptidase IV (DPPIV) is a multifunctional cell surface aminopeptidase with ubiquitous expression and it has a variety of functional properties in the development of human malignancies. In the present study, we showed the possible correlation between DPPIV/CD26 expression and less migratory potential with decreased MMP-2 expression in ovarian carcinoma cells. Moreover, induction of DPPIV/CD26 resulted in reduced expressions of MMP-2 and mesenchymal markers such as vimentin and SMA, with a less invasive potential and an epithelial morphologic change. This evidence implies that DPPIV/CD26 may play a crucial role in the antimetastatic potential in ovarian carcinoma.

A novel role for placental leucine aminopeptidase (P-LAP) as a determinant of chemoresistance in endometrial carcinoma cells.

In several recent studies, we have shown that P-LAP can be a poor prognostic factor and a factor of chemoresistance in endometrial carcinoma, especially in the advanced patients. In our study, we investigated whether P-LAP alters the expression of apoptosis regulatory proteins as a mechanism of drug resistance. We transfected P-LAP cDNA into A-MEC cells (endometrial adenocarcinoma cell line), and A-MEC-LAP cells displayed a 1.8-fold, 2.0-fold and 1.7-fold increase in IC(50) against paclitaxel, carboplatin and cisplatin respectively. Translational downregulation by siRNA2 to P-LAP on A-MEC-LAP cells demonstrated 60%, 51% and 58% decrease in IC(50). To investigate the mechanism of P-LAP-induced chemoresistance, we also assessed whether P-LAP transfection had an effect on carboplatin-induced apoptotic death of A-MEC cells. A-MEC and A-MEC-pc (transfected with vector alone) cells exhibited a strong apoptotic response to carboplatin, while A-MEC-LAP cells exhibited a weak apoptotic response. In an attempt to identify the mechanism of the inhibitory effect on apoptotic response to carboplatin, we next assessed the expression of cleaved caspases and PARP cleavage. While treatment of A-MEC-pc cells with carboplatin exhibited increased levels of cleaved caspase 3, caspase 7 and caspase 9 compared to that after no treatment, A-MEC-LAP cells did not show any expression of these caspases. These results suggest that P-LAP reduces sensitivity to anticancer drugs via inhibition of mitochondria-mediated apoptosis, and may be a molecular target for conquering anticancer drug resistance.