Epithelial ovarian cancer - more data, more questions?

The effect of calycosin-7-O-β-D-glucoside and its synergistic augmentation of cisplatin-induced apoptosis in SK-OV-3 cells

OBJECTIVE

This study aims to examine the synergetic augmentation of calycosin-7-O-β-D-glucoside (CG) on cisplatin (CDDP) to induce apoptosis of human epithelial ovarian SK-OV-3 cancer cells.

METHODS

The SK-OV-3 cells were divided into four groups: control, CDDP monotherapy, CG monotherapy, and combined CDDP and CG treatment. The cell counting kit-8 method was used to detect cell proliferation at different times and under different treatments. Hoechst 33258 staining and annexin V-FITC/propidium iodide double staining methods were used to observe the apoptosis of the SK-OV-3 cells. The caspase-3 enzyme activity detection method, quantitative reverse transcription-polymerase chain reaction, and western blot were used to detect the apoptosis-related factors and the activities of the enzyme in SK-OV-3 cells.

RESULTS

The inhibition rates of SK-OV-3 cell proliferation when exposed to 10 μM of CDDP, 50 μM of CG, and a combination of 10 μM of CDDP and 50 μM of CG were 23.2% ± 1.1%, 26.7% ± 2.0%, and 46.7% ± 1.3% after 48 h, respectively. Following the use of the drug combination, the apoptosis rate and caspase-3 enzyme activity were significantly higher than in the single-drug treatment group; in addition, the data differences were significant (p < 0.05). At the protein and ribonucleic acid levels, CG significantly enhanced the effect of CDDP on p53, caspase-3, caspase-9, Bax, and Bcl-2.

CONCLUSION

In vitro, CG significantly increases the CDDP-induced apoptosis of the SK-OV-3 cells through the p53 pathway at the cellular level. In addition, using the drugs in combination reduces the toxicity and side effects caused by using CDDP alone.

Palliative treatment for bowel obstruction in ovarian cancer: a meta-analysis

OBJECTIVE

To comprehensively evaluate and compare outcomes of surgical versus nonsurgical palliative interventions for bowel obstruction due to ovarian cancer.

METHODS

Studies were obtained from database search systems of Pubmed, Medline, Wiley, Springerlink, Kluwer, Web of science and Science direct. Data were analyzed by the meta-analysis method and the random-effect or fixed-effect model. The heterogeneity between the studies was evaluated by I² index and the data were analyzed using STATA version 14.1.

RESULTS

12 studies involving 2778 cases of bowel obstruction in ovarian cancer were included, including 1225 cases of surgery and 1553 cases of palliative nonsurgical treatment. Surgery group had significantly higher remission rate of bowel obstruction (OR = 0.350, 95% CI 0.067-1.819, P = 0.000),but had no manifesting difference in the recurrence rate compared no-surgery group (RR = 0.88, 95% CI 0.76-1.03, P = 0.106). In 30-day mortality rate, surgery group had higher mortality rate (RR = 0.453, 95% CI 0.161-1.272, P = 0.000). But, surgical treatment can markedly prolong survival period (HR = 0.333, 95% CI 0.275-0.390, P = 0.000) compared nonsurgical treatment.

CONCLUSIONS

Surgery can significantly relieve the symptom of intestinal obstruction, prolonging the survival period, but had no impact on the recurrence. Compared with no-surgery group, surgery group suffered higher 30-day mortality.

Ovarian Cancer Stem Cell Heterogeneity

Ovarian carcinoma features pronounced clinical, histopathological, and molecular heterogeneity. There is good reason to believe that parts of this heterogeneity can be explained by differences in the respective cell of origin, with a self-renewing fallopian tube secretory cell being likely responsible for initiation of an overwhelming majority of high-grade serous ovarian carcinomas (i.e., type II tumors according to the recent dualistic classification), whereas there are several mutually non-exclusive possibilities for the initiation of type I tumors, including ovarian surface epithelium stem cells, endometrial cells, or even cells of extra-Müllerian origin. Interestingly, both fallopian tube self-renewing secretory cells and ovarian surface epithelium stem cells seem to be characterized by an overlapping array of stemness signaling pathways, especially Wnt/β-catenin. Apart from this variability in the respective cell of origin, the particular clinical behavior of ovarian carcinoma strongly suggests an underlying stem cell component with a crucial impact. This becomes especially evident in high-grade serous ovarian carcinomas treated with classical chemotherapy, which entails a gradual evolution of chemoresistant disease without any apparent selection of clones carrying obvious chemoresistance-associated mutations. Several cell surface markers (e.g., CD24, CD44, CD117, CD133, and ROR1) as well as functional approaches (ALDEFLUOR™ and side population assays) have been used to identify and characterize putative ovarian carcinoma stem cells. We have recently shown that side population cells exhibit marked heterogeneity on their own, which can hamper their straightforward therapeutic targeting. An alternative strategy for stemness-depleting interventions is to target the stem cell niche, i.e., the specific microanatomical structure that secures stem cell maintenance and survival through provision of a set of stem cell-promoting and differentiation-antagonizing factors. Besides identifying direct or indirect therapeutic targets, profiling of side population cells and other ovarian carcinoma stem cell subpopulations can reveal relevant prognostic markers, as exemplified by our recent discovery of the Vav3.1 transcript variant, which filters out a fraction of prognostically unfavorable ovarian carcinoma cases.

CCNG1 (Cyclin G1) regulation by mutant-P53 via induction of Notch3 expression promotes high-grade serous ovarian cancer (HGSOC) tumorigenesis and progression

TP53 mutation is considerably common in advanced high-grade serous ovarian cancer (HGSOC) and significantly associated with a poor prognosis. In this study, we investigated the role of Cyclin G1 (CCNG1), a target gene of wild-type TP53 (P53wt), in HGSOC and the possible regulatory mechanism between TP53 mutant (P53mt) and CCNG1 in the progression of HGSOC. High expression level of CCNG1 was found in 61.3% of HGSOC tissues and only 18.2% in fimbriae of fallopian tubes. Additionally, overexpression of CCNG1 was significantly associated with a shorter overall survival (P < 0.0001) and progression-free survival (P < 0.0004) in HGSOC patients. In vitro, CCNG1 promoted both tumor cell motility by inducing epithelial-mesenchymal transition (EMT) and resistance to cisplatin (CDDP). In vivo, knockdown expression of CCNG1 inhibited cancer metastasis. Furthermore, P53mt increased the expression of CCNG1 by regulating Notch3 expression, and a positive correlation between CCNG1 and Notch3 protein expression was observed by Immunohistochemistry (IHC) (r = 0.39, P: 0.01528). In conclusion, the activation of P53mt-Notch3-CCNG1 pathway was responsible for tumor progression to advanced disease with correlation with worse prognosis in patients with HGSOC. These data suggest a possible molecular mechanism of disease and highlights CCNG1's potential role as a therapeutic target in HGSOC.

Value of [18F]FDG-PET/CT and CA125, serum levels and kinetic parameters, in early detection of ovarian cancer recurrence: Influence of histological subtypes and tumor stages

To assess the diagnostic accuracy of CA125, its kinetic values and positron emission tomography/computed tomography with 2-deoxy-2-[F]fluoro-D-glucose ([F]FDG-PET/CT), in relation with tumor characteristics for suspected recurrence of ovarian cancer. To evaluate the performance of CA125-related parameters as a selection criteria to perform a [F]FDG-PET/CT.A retrospective analysis of 69 [F]FDG-PET/CT for suspected recurrence of ovarian cancer was performed. All patients had 2 measurements of CA125, before PET/CT, to calculate kinetic values, as CA125vel (CA125vel = [CA125a - CA125b]/time) and CA125dt (CA125dt = [log2 × time]/[logCA125a - CA125b]). Maximum standard uptake value (SUVmax) was calculated. The diagnostic accuracy was calculated for all the variables and the optimal cut-off value of each of them by the receiver-operating characteristics (ROC) analysis. All the tests were compared with tumor characteristics and clinical-radiological evolution during follow-up of at least 6 months.Fifty-five cases were diagnosed of recurrence (11 with CA125 <35 U/mL), while 14 showed no disease (11 with CA125 < 35 U/mL). All of them were correctly cataloged by PET/CT. CA125, CA125vel, and SUVmax showed higher levels in recurrent patients (mean 129.54 U/mL, 24.58 U/mL per mo, and 8.69 g/mL, respectively) than in nonrecurrent (mean 20.35 U/mL, 0.60 U/mL per mo, and 0.64 g/mL, respectively). No statistical differences in CA125dt were found. Patients with recurrence of high-grade serous carcinoma (HGSC) showed higher CA125 and CA125vel, without differences in the rest of subtypes and International Federation of Gynecology and Obstetrics stages. The ROC analyses for CA125, CA125vel, and CA125dt showed an area under the curve (AUC) of 0.873 (95% confidence interval [CI] 0.77-0.969), 0.903 (95% CI 0.813-0.994), and 0.727 (95% CI 0.542-0.913), respectively, with an optimal cut-off point of 23.95 U/mL, 4.49 U/mL per mo, and 3.36 months, respectively, while for the SUVmax the AUC was of 0.982 (95% CI 0.948-1.000), and the cut-off point of 2. Multivariate regression analysis identified CA125 and CA125vel as predictors of recurrence.[F]FDG-PET/CT is more accurate than the parameters obtained from the CA125 to detect early recurrence. CA125vel is the most suitable parameter, mainly in HGSC. Levels of CA125vel ≥ 4.49 U/mL per mo facilitate earlier detection by the execution of a [F]FDG-PET/CT. The calculation of these parameters is independent of tumor stage at diagnosis.

Impact of ascites volume on clinical outcomes in ovarian cancer: A cohort study

OBJECTIVES

To investigate the impact of ascites volume on ovarian cancer outcomes.

METHODS

Clinicopathologic features of a cohort of patients with ovarian cancer were obtained from a curated database at a single institution. Progression free survival (PFS) and overall survival (OS) were recorded. Ascites volume at primary surgery was dichotomized at 2000mL and comparisons for high and low volume ascites were made. Additionally, to elucidate interactions between ascites and ovarian tumor progression, we evaluated the effect of intraperitoneal administrations of murine cell-free ascites versus saline in a syngeneic mouse model of epithelial ovarian cancer.

RESULTS

Out of 685 patients identified, 58% had ascites present at the time of initial surgery. Considering the volume of ascites continuously, each liter of ascites was associated with shorter PFS (HR=1.12, 95% CI: 1.07-1.17) and OS (HR=1.12, 95%CI: 1.07-1.17). Patients with ascites greater than the median of 2000mL had significantly shorter PFS (14.5months vs. 22.7months; p<0.001) and OS (27.7months vs. 42.9months; p<0.001). After adjusting for stage, presence of ascites was inversely associated with ability to achieve optimal cytoreductive surgery. Consistent with these correlative results in patients, intraperitoneal administrations of murine cell-free ascites accelerated ovarian cancer progression in mice.

CONCLUSIONS

The volume of ascites at initial diagnosis of ovarian cancer correlated with worse PFS and OS. The effect of large volume on prognosis is likely to be in part related to reduced likelihood for complete resection of tumor (R0). If these findings are confirmed in independent studies, consideration should be made to add the presence of large volume ascites at diagnosis to the staging criteria for ovarian cancer.

Prognostic value of miliary versus non-miliary sub-staging in advanced ovarian cancer

OBJECTIVE

The presence of miliary disease during initial ovarian cancer debulking may reflect a distinct mode of peritoneal spread independent from size-based tumor staging and may explain variation in response to treatment and survival outcomes. To infer the prevalence, presentation and clinical implications of miliary disease we reviewed existing surgical records.

METHODS

Reports were available for 1008 primary debulking surgeries for ovarian, primary peritoneal or fallopian tube cancer between 2001 and 2015 (685 reports from 2005 to 2015). Clinical outcome data was available for 938 patients. We analyzed a high-stage sub-cohort for survival (N=436).

RESULTS

Most records were evaluable for miliary disease (761/938); for these, the miliary phenotype was highly prevalent (249/761, 32.7%) and often accompanied by ascites (185/249, 74%). While optimal debulking rates were unaffected by miliary disease, total resection (R0) rates were poorer. Liver, stomach, spleen or bladder appeared to be sporadically involved while the omentum, mesentery, bowel, peritoneum and diaphragm were affected simultaneously (Spearman rho>0.5). Overall, miliary disease was associated with worse progression free survival, overall survival, and time from relapse to death independent of stage. Survival effects were particularly strong for Stage IV disease where median overall survival varied by over 30months (log-rank p=0.002).

CONCLUSIONS

Miliary disease is an identifiable surgical phenotype reflecting a distinct clinical trajectory that adds prognostic information to standard disease burden-based staging. These findings should permit further retrospective investigation in a wider cohort and prompt the consideration of prospective structured operative reporting standards and treatment strategies.

High expression of CTHRC1 promotes EMT of epithelial ovarian cancer (EOC) and is associated with poor prognosis

Collagen triple helix repeat-containing 1 (CTHRC1) is aberrantly overexpressed in multiple malignant tumors. However, the expression characteristics and function of CTHRC1 in epithelial ovarian cancer (EOC) remain unclear. We found that CTHRC1 expression was up-regulated in the paraffin-embedded EOC tissues compared to borderline or benign tumor tissues. CTHRC1 expression was positively correlated with tumor size (p = 0.008), menopause (p = 0.037), clinical stage (p = 0.002) and lymph node metastasis (p < 0.001) and was also an important prognostic factor for the overall survival of EOC patients, as revealed by Kaplan-Meier analysis. CTHRC1 increased the invasive capabilities of EOC cells in vitro by activating the Wnt/β-catenin signaling pathway. We showed that ectopic transfection of CTHRC1 in EOC cells up-regulated the expression of EMT markers such as N-cadherin and vimentin, and EMT-associated transcriptional factor Snail. Knockdown of CTHRC1 expression in EOC cells resulted in down-regulation of N-cadherin, vimentin, Snail and translocation of β-catenin. Collectively, CTHRC1 may promote EOC metastasis through the induction of EMT process and serve as a potential biomarker for prognosis as well as a target for therapy.

Procyanidin-rich extract of natural cocoa powder causes ROS-mediated caspase-3 dependent apoptosis and reduction of pro-MMP-2 in epithelial ovarian carcinoma cell lines

Over the last four centuries, cocoa and chocolate have been described as having potential medicinal value. As of today, Theobroma cacao L. (Sterculiaceae) and its products are consumed worldwide. They are of great research interest because of the concentration dependent antioxidant as well as pro-oxidant properties of some of their polyphenolic constituents, specially procyanidins and flavan-3-ols such as catechin. This study was aimed at investigating the cellular and molecular changes associated with cytotoxicity, caused due pro-oxidant activity of cocoa catechins and procyanidins, in ovarian cancer cell lines. Extract of non-alkalized cocoa powder enriched with catechins and procyanidins was used to treat human epithelial ovarian cancer cell lines OAW42 and OVCAR3 at various concentrations ≤1000μg/mL. The effect of treatment on intracellular reactive oxygen species (ROS) levels was determined. Apoptotic cell death, post treatment, was evaluated microscopically and using flow cytometry by means of annexin-propidium iodide (PI) dual staining. Levels of active caspase-3 as a pro-apoptotic marker and matrix metalloproteinase 2 (MMP2) as an invasive potential marker were detected using Western blotting and gelatin zymography. Treatment with extract caused an increase in intracellular ROS levels in OAW42 and OVCAR3 cell lines. Bright field and fluorescence microscopy of treated cells revealed apoptotic morphology and DNA damage. Increase in annexin positive cell population and dose dependent upregulation of caspase-3 confirmed apoptotic cell death. pro-MMP2 was found to be downregulated in a dose dependent manner in cells treated with the extract. Treated cells also showed a reduction in MMP2 activity. Our data suggests that cocoa catechins and procyanidins are cytotoxic to epithelial ovarian cancer, inducing apoptotic morphological changes, DNA damage and caspase-3 mediated cell death. Downregulation of pro-MMP2 and reduction in active MMP2 levels imply a decrease in invasive potential of the cells. Apoptosis and MMP2 downregulation appear to be linked to the increase in intracellular ROS levels, caused due to the prooxidant effect of cocoa procyanidin extract.

The role of Cyclin G1 in cellular proliferation and apoptosis of human epithelial ovarian cancer

Cyclin G1 plays an essential role in the development of human carcinoma. Here, we characterized the clinical significance of Cyclin G1 and investigated its role in cellular proliferation and apoptosis of epithelial ovarian cancer (EOC). Western blot was used to evaluate the expression of Cyclin G1 in nine fresh EOC tissues and three fresh normal ovarian tissues. Immunohistochemistry analysis was performed on formalin-fixed paraffin-embedded section of 119 cases of EOCs. Using cell counting kit (CCK)-8 and colony formation assays, we analyzed the effect of Cyclin G1 in cellular proliferation of EOC. Besides, the immunofluorescence and flow cytometry analysis was performed to study the role of Cyclin G1 in cellular apoptosis of EOC. We found Cyclin G1 was up-regulated in EOC tissues compared with the normal ovary tissues. Cyclin G1 expression in EOC was closely correlated with differentiation grade (P = 0.009) and malignant tumor cells in ascites (P = 0.009). The Kaplan-Meier curve showed that higher expression of Cyclin G1 was associated with significantly shorter survival in EOC patients. Multivariate analysis suggested Cyclin G1 expression was an independent prognostic factor for overall survival. CCK-8 and colony formation assays revealed that depletion of Cyclin G1 inhibited the proliferation and clone formation. Combined immunofluorescence and flow cytometry analysis showed that silencing of Cyclin G1 with shRNA could promote apoptosis of ovarian cancer cells. Additionally, the result of immunoprecipitation test showed Cyclin G1 interacted with CDK2 in EOC cells. In summary, our findings suggest that Cyclin G1 may be involved in the prognosis of EOC patients and be a useful therapeutic target for EOC.