Randomized trial of cisplatin and carboplatin versus cisplatin, vinblastine and bleomycin in ovarian cancer

Programmed cell death, redox imbalance, and cancer therapeutics

Cancer cells are disordered by nature and thus featured by higher internal redox level than healthy cells. Redox imbalance could trigger programmed cell death if exceeded a certain threshold, rendering therapeutic strategies relying on redox control a possible cancer management solution. Yet, various programmed cell death events have been consecutively discovered, complicating our understandings on their associations with redox imbalance and clinical implications especially therapeutic design. Thus, it is imperative to understand differences and similarities among programmed cell death events regarding their associations with redox imbalance for improved control over these events in malignant cells as well as appropriate design on therapeutic approaches relying on redox control. This review addresses these issues and concludes by bringing affront cold atmospheric plasma as an emerging redox controller with translational potential in clinics.

Inhibition of ZEB1 leads to inversion of metastatic characteristics and restoration of paclitaxel sensitivity of chronic chemoresistant ovarian carcinoma cells

ZEB1, a member of the zinc-finger E-box binding homeobox family, is considered to play a crucial role in cancer progression and metastasis. In the current study, we investigated the role of ZEB1 in metastasis and chronic chemoresistance of epithelial ovarian carcinoma (EOC) cells. Using several EOC and acquired paclitaxel (PTX)-resistant EOC cell lines, we investigated whether silencing ZEB1 led to a reversal of the chemoresistance and metastatic potential in vitro and in vivo. Subsequently, the expression of ZEB1 in EOC tissues and its association with the oncologic outcome were investigated. According to the immunohistochemical staining of EOC tissues, as the positivity of ZEB1 expression was increased, the overall survival of EOC patients became poorer (P = 0.0022 for trend). Additionally, cell migration and invasion were significantly decreased by ZEB1 silencing in both PTX-sensitive and PTX- resistant cells. Although PTX-sensitivity was not changed by silencing ZEB1 in parental EOC cells, the depletion of ZEB1 made the PTX-resistant EOC cells more sensitive to PTX treatment. In an animal model, mice injected with ZEB1-silencing PTX-resistant cells survived for longer than the control cell-injected mice. Although the intravenous injection of PTX did not affect the tumor weight of shCtrl cells, the tumor weight of shZEB1 cells was significantly reduced by PTX treatment. The current data indicate the possible involvement of ZEB1 in the metastasis and paclitaxel resistance of EOC, and suggest that targeting this molecule may reverse the malignant potential and improve the oncologic outcome for EOC patients.

Exendin-4 inhibits growth and augments apoptosis of ovarian cancer cells

Glucagon-like peptide (GLP)-1 promotes proliferation and survival in β-cell; however, whether GLP-1 receptor agonists promote growth of human ovarian cancer cells remain unknown. We aimed to explore the effects of GLP-1 agents on ovarian cancer cells. GLP-1 receptor expression in human ovarian cancer tissues was detected by immunohistochemical analysis. The effects of exendin-4, a GLP-1R agonist, were investigated on proliferation, migration and invasion, apoptosis in vitro and tumor formation in nude mice of ovarian cancer cells. Our study demonstrated that GLP-1R expressed in both human ovarian cancer tissues and cell lines. Exendin-4 inhibited growth, migration and invasion and enhanced apoptosis of ovarian cancer cells through inhibition of the PI3K/Akt pathway. And exendin-4 attenuated tumor formation by ovarian cancer cells in vivo. Our study suggests that GLP-1R agonists do not promote the growth of ovarian cancer and may even have anticancer effect on selected diabetic patients with ovarian cancer.

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.

Twist expression predicts poor clinical outcome of patients with clear cell carcinoma of the ovary

OBJECTIVES

Twist is a highly conserved basic helix-loop-helix transcription factor that regulates the expression of E-cadherin and promotes the epithelial-mesenchymal transition, which is critical for tumor infiltration. We examined the distribution and expression of this molecule in clear cell carcinoma of the ovary (CCC) to elucidate their clinical significance.

METHODS

Paraffin sections from CCC tissues (n = 27) were immunostained with Twist antibody and staining intensities were evaluated. Stratified with various clinicopathological factors, overall survival (OS) and progression-free survival (PFS) were evaluated.

RESULTS

In the 27 carcinomas, negative Twist immunoexpression was observed in 14 cases (51.9%), and positive immunoexpression in 13 (48.1%). Twist, when categorized into negative versus positive expression, was associated with FIGO stage and peritoneal cytology. In addition, positive Twist expression significantly predicted a poorer OS and PFS compared with negative expression (p < 0.0001). Furthermore, the multivariate analyses revealed that positive Twist expression was an independent prognostic factor for OS and PFS of patients with CCC in this study (p = 0.0077 and 0.0033, respectively).

CONCLUSION

The current findings suggest that the assessment of Twist immunoreactivity may be a useful prognostic indicator and that Twist may play a critical role in the progression of CCC.

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.

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.

Long-term follow-up and prognostic factor analysis in clear cell adenocarcinoma of the ovary

BACKGROUND AND OBJECTIVES

There were a few reports of a large number of patients with clear cell adenocarcinoma (CCA) of the ovary because of the low incidence of CCA. This study compared the clinical factors affecting long-term survival of patients with CCA to those with serous cystadenocarcinoma (SCA).

METHODS

One hundred and seventy-eight CCA and 311 SCA patients treated between 1987 and 2000 were retrospectively evaluated. Differences in survival rates were calculated using log-rank test and Cox's proportional hazards analysis was used to identify independent prognostic factors.

RESULTS

The ratio of stage I was significantly higher than that of SCA. There was no significant difference of 8-year survival rate in each stage between CCA and SCA. However, the patients with stage IIIb or IIIc CCA showed significantly worse prognosis than those with SCA. Positive peritoneal or ascitic cytology, the presence of residual tumor, more than 100 ml ascites were demonstrated to have the significant impact on survival by univariate analysis. Multivariate analysis demonstrated that stage, more than 100 ml ascites, and the presence of residual tumor were significant prognostic factors of CCA overall survival.

CONCLUSIONS

Distribution of stage and substage differed between CCA and SCA in this study. Thus, substaging is quite important for comparison of prognoses between histologies, and CCA showed poorer prognoses than serous adenocarcinoma in stages IIIb and IIIc.

Neutral Endopeptidase 24.11/CD10 Suppresses Progressive Potential in Ovarian Carcinoma In vitro and In vivo

Recently, numerous studies have shown that endothelin-1 (ET-1) is expressed in ovarian carcinoma and that ET-1 selectively acts as an autocrine or paracrine growth factor through the endothelin A receptor (ET(A)R), and is involved in cell proliferation, invasiveness, neovascularization, and prevention of apoptosis. Neutral endopeptidase 24.11 (NEP) is a cell surface aminopeptidase with a ubiquitous expression and is capable of degrading a number of bioactive peptides including ET-1. Our previous report showed that stromal NEP expression in ovarian carcinoma was down-regulated as the histologic grade advanced. Here, we confirmed that NEP was expressed in tumor cells as well as stromal tissues in ovarian carcinoma, and investigated the functions of NEP in this carcinoma. We showed that there was a significant decrease in cell proliferation and invasiveness with a reduction in the concentration of ET-1 in the conditioned medium on the NEP overexpression of NEP in ovarian carcinoma cells. In addition, the overexpression of NEP enhanced susceptibility to paclitaxel, resulting in an increased occurrence of apoptotic morphologic change. Furthermore, tumorigenesis was reduced in vivo with the overexpression of NEP, down-regulation of both matrix metalloproteinase-2, and vascular endothelial growth factor expression. This evidence suggests that NEP functionally suppresses the progression of ovarian carcinoma and further study of this enzyme may reveal an effective way to target ET-1 for the treatment of this carcinoma.

Recombinant Adeno-Associated Virus 2-Mediated Antiangiogenic Prevention in a Mouse Model of Intraperitoneal Ovarian Cancer

Purpose: In the present study, we sought to determine the potential of sustained transgene expression by a single i.m. administration of recombinant adeno-associated virus 2 (rAAV) encoding angiostatin and endostatin in inhibiting i.p. ovarian cancer growth and dissemination in a preclinical mouse model.

Experimental Design: Cohorts of female athymic nude mice received either no virus or 1.2 × 1011 particles of rAAV encoding green fluorescence protein or endostatin plus angiostatin, i.m. Three weeks later, the mice were i.p. injected with 106 human epithelial ovarian cancer cell line SKOV3.ip1. As a measure of effectiveness of the therapy, tumor weight, abdominal distension, ascites volume and vascular endothelial growth factor level, and tumor weight were determined. Immunohistochemistry was done to determine tumor cell apoptosis and endothelial cell proliferation following the therapy. Tumor-free survival was recorded as the end point.

Results: Results indicated a significant tumor-free survival (P &lt; 0.003) following therapy with rAAV encoding endostatin and angiostatin compared with untreated or rAAV-green fluorescence protein–treated mice. Ascites volume in rAAV endostatin and angiostatin–treated mice was significantly lower than naive mice and contained less hemorrhage and tumor conglomerates. The level of vascular endothelial growth factor in the ascites of antiangiogenic vector treated mice was also significantly less compared with the untreated mice. Immunohistochemical analyses indicated increased tumor cell apoptosis and decreased blood vasculature following rAAV endostatin and angiostatin treatment.

Conclusion: The results indicate that antiangiogenic genetic prevention from stable systemic levels of angiostatin and endostatin by i.m. administration of rAAV can be used for the treatment of i.p. ovarian cancer growth and dissemination.

Suppression of invasion and peritoneal carcinomatosis of ovarian cancer cells by overexpression of AP-2alpha

A previous report demonstrated that AP-2alpha favors the survival of ovarian cancer patients by clinical findings. However, the functional roles of AP-2alpha in human ovarian cancers have not been determined. To clarify the roles, we overexpressed AP-2alpha in SKOV3 human ovarian cancer cells, which originally possess little AP-2alpha. AP-2alpha overexpression changed cell morphology from spindle to epithelioid type and suppressed cell proliferation and invasion, which would be partially correlated with decreased phosphorylation levels of the erbB2, Akt and ERK pathways, increased E-cadherin and reduced pro-matrix metalloproteinase-2 levels. Moreover, nude mice intraperitoneally injected with AP-2alpha-overexpressing cells survived longer than those with neo-transfected cells. The present data represent the first direct evidence that AP-2alpha plays a tumor suppressive role in ovarian cancer.

Preoperative findings in non-gynecologic carcinomas metastasizing to the ovaries

This study evaluated whether preoperative findings are useful prognostic indicators in patients with non-gynecologic carcinomas metastasizing to the ovaries. Fifty-three patients were analyzed. Primary sites of carcinoma were discovered after gynecologic surgery in 20 patients. In 10 patients, primary sites of carcinoma were discovered during gynecologic surgery. Thirty-one patients received surgery on the primary site before gynecologic surgery. The primary site could not be identified in 2 patients. The 5-year survival rate was 40.0% in patients, who underwent surgery on the primary site before gynecologic surgery. However, the 5-year survival rate was 12.2% in patients, who underwent surgery on the primary site during or after gynecologic surgery. The CEA level was significantly lower in the stomach primary group than in the intestine primary group. However, CA125 was the only marker significantly affecting survival. In comparison with primary ovarian carcinoma, the sensitivity of CEA was significantly higher for non-gynecologic ovarian carcinoma, while that of CA125 was significantly less sensitive for non-gynecologic ovarian carcinoma. In conclusion, the prognosis was better in patients, who had undergone resection of primary carcinoma before gynecologic surgery on non-gynecologic ovarian carcinoma. CEA is a useful marker to distinguish non-gynecologic from primary ovarian carcinoma, while CA125 is the only significant prognostic marker for non-gynecologic ovarian carcinoma.

Long-term prognosis of stage I ovarian carcinoma. Prognostic importance of intraoperative rupture

OBJECTIVE

There are a few long-term follow-up studies of patients with stage I ovarian carcinoma. The objective of this study was to evaluate prognostic factors for long-term survival.

METHODS

Two hundred fourteen stage I ovarian carcinomas (registered by the Tokai Ovarian Tumor Study Group from 1988 to 1999) were analyzed. Staging according to the International Federation of Gynecology and Obstetrics was set without considering the pathologic findings of the lymph nodes. Stage Ic was divided into Ic(b) and other Ic.

RESULTS

Seventy-four patients were stage Ia, 2 were stage Ib, and 138 were stage Ic, consisting of 75 Ic(b) and 63 other Ic patients. The ratios of stage Ic to Ia and stage Ic(b) to Ic were highest in clear-cell adenocarcinoma among histologies analyzed. There were significant differences in disease-free survival curves between each group. In clear cell adenocarcinoma, there was a significant difference in disease- free survival curves between stage Ic(b) and other Ic (p = 0.0373), while this tendency was also observed in other histologies except for mucinous carcinoma. Multivariate analysis demonstrated that substage was a significant prognostic factor of both disease-free and overall survival.

CONCLUSIONS

Stage Ic(b) patients showed poorer survival than stage Ia patients but better than survival in other Ic. Thus, cautious treatment of ovarian tumor during surgery is quite important to avoid rupture.

Prognostic factors of secondary ovarian carcinoma

OBJECTIVE

Although the ovaries are common sites of metastases from a variety of primary neoplasms excluding carcinomas of the genital tract, there were few reports concerning survival and prognostic factors. The objective of this study was to assess the clinical factors affecting survival.

METHODS

Fifty-three secondary ovarian carcinomas excluding metastases from genital tract carcinoma were registered by the Tokai Ovarian Tumor Study Group from 1989 to 1999. FIGO staging was set without considering the pathologic findings of the lymph nodes and the primary tumors.

RESULTS

Twenty-four patients were stage I, 11 were stage II, 16 were stage III, and 2 were stage IV. There were significant differences in the survival curves between the early stages (I and II) and advanced stages (III and IV). The 5-year survival rate for patients without residual tumors was 39.9%, while all patients with residual tumors after surgery died within 33 months. The most frequent primary tumor was large intestinal carcinoma, and the second was gastric carcinoma. The 5-year survival rate for patients with large intestinal primary tumors was significantly better than that with stomach tumors. Multivariate analysis demonstrated that tumor stage and primary tumor sites were significant prognostic factors.

CONCLUSION

FIGO staging without considering lymph node involvement and the primary tumor was a significant prognostic factor, and prognostic factors for primary ovarian carcinomas can be applied to secondary ovarian carcinomas. Furthermore, the primary tumor site was also an important prognostic factor for survival.