Background: Twist, a basic helix–-loop–helix transcription factor, has been reported to be associated with the development and progression of human cancer. We examined the distribution and expression of Twist in cervical cancer to examine its clinical significance. Patients and methods: We examined the distribution and expression of Twist in 101 cervical cancer specimens and determined the association between their expression and the clinico-pathological features observed, including patient outcome. Results: Of the 101 specimens, 55 cases were negative for Twist immuno-expression, whereas 46 were positive. When categorized into negative versus positive expression, Twist was not associated with any of the clinico-pathological parameters examined. Positive Twist expression significantly predicted poorer overall survival (OS) and progression-free survival (PFS) when compared with negative expression (P < 0.01). In the multivariate analyses, positive Twist expression was an independent prognostic factor for OS (P < 0.05). Conclusions: Our data imply that positive Twist expression seems to be a useful marker in patients with cervical cancer likely to have an unfavorable clinical outcome.

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.

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.

The neurohypophyseal nonapeptide oxytocin (OT) is involved in many biologic functions and regulation of cell proliferation under both physiologic and neoplastic conditions. In some cases, OT exhibits an oxytocin receptor (OTR)‐mediated antiproliferative effect on cancer cells. In this study, we examined the effects of OT on ovarian carcinoma progression in vitro and in vivo. We investigated the inhibitory effects of OT on cell growth, invasion and migration in vitro. Furthermore, we examined the OT effects in vivo ovarian carcinoma model. We demonstrated OTR expressions in the large majority of ovarian carcinoma tissues, and OT inhibited not only proliferation but also migration and invasion in ovarian carcinoma cells in vitro. Furthermore, we examined the mechanisms of the antiinvasive ability of OT. Secretion of matrix metalloproteinase 2 was slightly inhibited by 10⁻⁷ M OT, while treatment with 10⁻⁷ M OT for 24 hr remarkably enhanced the expression of E‐cadherin. In addition, our in vivo study showed that intraperitoneal administration of OT resulted in the reduction of intraperitoneal dissemination of ovarian carcinoma cells. Mean tumor burden in the OT‐treated group (0.2 ± 0.11 g) was significantly (p < 0.05) less than that of physiologic saline‐treated group (0.5 ± 0.54 g). This evidence implies that OT may functionally suppress peritoneal dissemination in ovarian carcinoma.

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 IC₅₀ 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 IC₅₀. 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.