Treatment goals in ovarian cancer

Platinum-induced mitochondrial OXPHOS contributes to cancer stem cell enrichment in ovarian cancer

Background

Platinum based agents—cisplatin and carboplatin in combination with taxanes are used for the treatment of ovarian cancer (OC) patients. However, the majority of OC patients develop recurrent, platinum resistant disease that is uniformly fatal. Platinum treatment enriches for chemoresistant aldehyde dehydrogenase (ALDH) + ovarian cancer stem cells (OCSCs), which contribute to tumor recurrence and disease relapse. Acquired platinum resistance also includes metabolic reprograming and switching to oxidative phosphorylation (OXPHOS). Chemosensitive cells rely on glycolysis while chemoresistant cells have the ability to switch between glycolysis and OXPHOS, depending on which pathway drives a selective advantage for growth and chemoresistance. High expression of genes involved in OXPHOS and high production of mitochondrial ROS are characteristics of OCSCs, suggesting that OCSCs favor OXPHOS over glycolysis. Based on connections between OCSCs, chemoresistance and OXPHOS, we hypothesize that platinum treatment induces changes in metabolism that contribute to platinum-induced enrichment of OCSCs.

Methods

The effect of cisplatin on mitochondrial activity was assessed by JC1 staining and expression of OXPHOS genes by RT-qPCR. Cisplatin-induced changes in Sirtuin 1 (SIRT1) levels and activity were assessed by western blot. Small molecule inhibitors of mitochondrial complex I and SIRT1 were used to determine if their enzymatic activity contributes to the platinum-induced enrichment of OCSCs. The percentage of ALDH + OCSCs in OC cells and tumor tissue from xenograft models across different treatment conditions was analyzed using ALDEFLUOR assay and flow cytometry.

Results

We demonstrate that platinum treatment increases mitochondrial activity. Combined treatment of platinum agents and OXPHOS inhibitors blocks the platinum-induced enrichment of ALDH + OCSCs in vitro and in vivo. Furthermore, platinum treatment increases SIRT1 levels and subsequent deacetylase activity, which likely contributes to the increase in platinum-induced mitochondrial activity.

Conclusions

These findings on metabolic pathways altered by platinum-based chemotherapy have uncovered key targets that can be exploited therapeutically to block the platinum-induced enrichment of OCSCs, ultimately improving the survival of OC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03447-y.

The role of vascular endothelial growth factor inhibitors in the treatment of epithelial ovarian cancer

Advanced epithelial ovarian, fallopian tube and primary peritoneal cancers (EOC) are a leading cause of gynaecological cancer-associated mortality and angiogenesis plays a key role in their growth. Vascular endothelial growth factor inhibitors (VEGFi) disrupt angiogenesis and improve the response rate, progression-free survival and in some cases, overall survival, when administered with and following cytotoxic chemotherapy, irrespective of the platinum sensitivity of EOC. Recent data have identified new indications for VEGFi in EOC: repeated exposure to VEGFi in the first- and then second-line treatment has sustained clinical efficacy; combinations of VEGFi with poly (ADP-ribose) polymerase inhibitors (PARPi) have proven effective as first-line or second-line maintenance regimens. However, recent trial data have not shown improved outcomes with combinations of VEGFi and immune checkpoint inhibitors. There remains a critical need to optimise patient selection for these effective yet somewhat toxic and expensive treatments. The search continues for validated biomarkers to optimise the use of VEGFi, of which the most promising at present is plasma Tie2. Based upon these studies, we propose a model of care incorporating VEGFi into the treatment of EOC, highlighting the need to change from the prescription of single courses of VEGFi, to allow use and re-use as clinically indicated.

To Enhance or Not to Enhance? The Role of Contrast Medium 18F-FDG PET/CT in Recurrent Ovarian Carcinomas

Background and Objectives: ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/X-ray computed tomography (PET/CT) represents the mainstay diagnostic procedure for suspected ovarian cancer (OC) recurrence. PET/CT can be integrated with contrast medium and in various diagnostic settings; however, the effective benefit of this procedure is still debated. We aimed to compare the diagnostic capabilities of low-dose and contrast-enhanced PET/CT (PET/ldCT and PET/ceCT) in patients with suspected ovarian cancer relapse. Materials and Methods: 122 OC patients underwent both PET/ldCT and PET/ceCT. Two groups of nuclear medicine physicians and radiologists scored the findings as positive or negative. Clinical/radiological follow-up was used as ground truth. Sensitivity, specificity, negative/positive predictive value, and accuracy were calculated at the patient and the lesion level. Results: A total of 455 and 474 lesions were identified at PET/ldCT and PET/ceCT, respectively. At the lesion level, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were not significantly different between PET/ldCT and PET/ceCT (98%, 93.3%, 97.4%, 94.9%, and 96.9% for PET/ldCT; 99%, 95.5%, 98.3%, 97%, and 98% for PET/ceCT, p = ns). At the patient level, no significant differences in these parameters were identified (e.g., p = 0.22 and p = 0.35 for accuracy, in the peritoneum and lymph nodes, respectively). Smaller peritoneal/lymph node lesions close to physiological FDG uptake sources were found in the cases of misidentification by PET/ldCT. PET/ceCT prompted a change in clinical management in four cases (3.2%) compared to PET/ldCT. Conclusions: PET/ceCT does not perform better than PET/ldCT but can occasionally clarify doubtful peritoneal findings on PET/ldCT. To avoid unnecessary dose to the patient, PET/ceCT should be excluded in selected cases.

Associations between DNA Damage and PD-L1 Expression in Ovarian Cancer, a Potential Biomarker for Clinical Response

Simple Summary

This work establishes that ovarian tumors contain persistent oxidative DNA damage levels that can be measured using Repair Assisted Damage Detection (RADD). The persistent DNA damage correlates with increased protein expression of PD-L1, establishing a link between genomic instability and PD-L1 expression across ovarian tumors. DNA damage may be a potential biomarker for immunotherapy.

Abstract

Programmed death ligand-1 (PD-L1) inhibitors are currently under investigation as a potential treatment option for ovarian cancer. Although this therapy has shown promise, its efficacy is highly variable among patients. Evidence suggests that genomic instability influences the expression of PD-L1, but little is known about this relationship in ovarian cancer. To examine the relationship between PD-L1 expression and genomic instability, we measured DNA damage using Repair Assisted Damage Detection (RADD). We then correlated the presence of persistent DNA damage in the ovarian tumor with protein expression of PD-L1 using immunohistochemistry. Ovarian tumors showed a high prevalence of oxidative DNA damage. As the level of oxidative DNA damage increased, we saw a significant correlation with PD-L1 expression. The highest correlation between DNA damage and PD-L1 expression was observed for mucinous ovarian tumors (r = 0.82), but a strong correlation was also observed for high grade serous and endometrioid tumors (r = 0.67 and 0.69, respectively). These findings link genomic instability to PD-L1 protein expression in ovarian cancer and suggest that persistent DNA damage can be used as a potential biomarker for patient selection for immunotherapy treatment.

Pretreatment with LCK inhibitors chemosensitizes cisplatin-resistant endometrioid ovarian tumors

Background

Ovarian cancer is the most fatal gynecologic malignancy in the United States. While chemotherapy is effective in the vast majority of ovarian cancer patients, recurrence and resistance to standard systemic therapy is nearly inevitable. We discovered that activation of the non-receptor tyrosine kinase Lymphocyte Cell-Specific Protein-Tyrosine Kinase (LCK) promoted cisplatin resistance. Here, we hypothesized that treating high grade, platinum resistant endometrioid cancer cells with an LCK inhibitor (LCKi) followed by co-treatment with cisplatin would lead to increased cisplatin efficacy. Our objective was to assess clinical outcomes associated with increased LCK expression, test our hypothesis of utilizing LCKi as pre-treatment followed by co-treatment with cisplatin in platinum resistant ovarian cancer in vitro, and evaluate our findings in vivo to assess LCKi applicability as a therapeutic agent.

Results

Kaplan-Meier (KM) plotter data indicated LCK expression is associated with significantly worse median progression-free survival (HR 3.19, p = 0.02), and a trend toward decreased overall survival in endometrioid ovarian tumors with elevated LCK expression (HR 2.45, p = 0.41). In vitro, cisplatin resistant ovarian endometrioid cells treated first with LCKi followed by combination LCKi-cisplatin treatment showed decreased cell viability and increased apoptosis. Immunoblot studies revealed LCKi led to increased expression of phosphorylated H2A histone family X (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma$$\end{document}γ-H2AX), a marker for DNA damage. In vivo results demonstrate treatment with LCKi followed by LCKi-cisplatin led to significantly slowed tumor growth.

Conclusions

We identified a strategy to therapeutically target cisplatin resistant endometrioid ovarian cancer leading to chemosensitization to platinum chemotherapy via treatment with LCKi followed by co-treatment with LCKi-cisplatin.

Cofilin: A Promising Protein Implicated in Cancer Metastasis and Apoptosis

Cofilin is an actin-binding protein that regulates filament dynamics and depolymerization. The over-expression of cofilin is observed in various cancers, cofilin promotes cancer metastasis by regulating cytoskeletal reorganization, lamellipodium formation and epithelial-to-mesenchymal transition. Clinical treatment of cancer regarding cofilin has been explored in aspects of tumor cells apoptosis and cofilin related miRNAs. This review addresses the structure and phosphorylation of cofilin and describes recent findings regarding the function of cofilin in regulating cancer metastasis and apoptosis in tumor cells.

Platinum-Induced Ubiquitination of Phosphorylated H2AX by RING1A Is Mediated by Replication Protein A in Ovarian Cancer

Platinum resistance is a common occurrence in high-grade serous ovarian cancer and a major cause of ovarian cancer deaths. Platinum agents form DNA cross-links, which activate nucleotide excision repair (NER), Fanconi anemia, and homologous recombination repair (HRR) pathways. Chromatin modifications occur in the vicinity of DNA damage and play an integral role in the DNA damage response (DDR). Chromatin modifiers, including polycomb repressive complex 1 (PRC1) members, and chromatin structure are frequently dysregulated in ovarian cancer and can potentially contribute to platinum resistance. However, the role of chromatin modifiers in the repair of platinum DNA damage in ovarian cancer is not well understood. We demonstrate that the PRC1 complex member RING1A mediates monoubiquitination of lysine 119 of phosphorylated H2AX (γH2AXub1) at sites of platinum DNA damage in ovarian cancer cells. After platinum treatment, our results reveal that NER and HRR both contribute to RING1A localization and γH2AX monoubiquitination. Importantly, replication protein A, involved in both NER and HRR, mediates RING1A localization to sites of damage. Furthermore, RING1A deficiency impairs the activation of the G₂-M DNA damage checkpoint, reduces the ability of ovarian cancer cells to repair platinum DNA damage, and increases sensitivity to platinum. IMPLICATIONS: Elucidating the role of RING1A in the DDR to platinum agents will allow for the identification of therapeutic targets to improve the response of ovarian cancer to standard chemotherapy regimens.

Highly expressed STAT1 contributes to the suppression of stemness properties in human paclitaxel-resistant ovarian cancer cells

Signal transducer and activator of transcription-1 (STAT1) is an important factor in various cellular processes. The cancer stem cell (CSC) is considered as a tumor-initiating cell that drives the inner hierarchy in many cancers including epithelial ovarian cancer (EOC). Here, we explored for the first time the regulation of STAT1 on stemness properties in chemoresistant EOC cells. The paclitaxel (PTX)-resistant EOC cell line (OV3R-PTX) was derived from PTX-sensitive OVCAR-3 cells treated by the PTX regimen. A single cell clone OV3R-PTX-B4 was selected by fluorescence-activated cell sorting. PTX-resistant cells grew slowly in conventional 2D and 3D cultures, but tumor xenograft with PTX-resistant cells grew fast in nude mice. Interestingly, OV3R-PTX-B4 cells shared the characteristics of CSCs and stemness properties were found to be increased in the non-adherent spheroid culture system. The PTX-resistant cells had a high expression of CSC-related markers and low expression of STAT1 that had a high methylation level of CpG in its promoter region. Overexpressed STAT1 suppressed stemness properties, cell proliferation, and colony formation and favored the overall survival of patients with EOC. In summary, these data indicate a regulatory mechanism of STAT1 underlying drug resistance and provide a potential therapeutic application for EOC patients with PTX resistance.

Regulation of REG4 Expression and Prediction of 5-Fluorouracil Sensitivity by CDX2 in Ovarian Mucinous Carcinoma

BACKGROUND/AIM

The biological importance of the caudal-related homeobox transcription factor CDX2 in acquiring resistance to anticancer drugs has been studied in ovarian mucinous carcinoma. CDX2 promotes the expression of multidrug resistance 1 (MDR1) and confers resistance to paclitaxel. The regenerating islet-derived family member 4 (REG4) gene is a potential target gene of CDX2. In this study, we investigated the relationship between the expression of CDX2 and Reg IV and the regulation of Reg IV expression and examined novel chemotherapeutic regimens.

MATERIALS AND METHODS

The regulation of Reg IV expression by CDX2 and sensitivity of 5-fluorouracil (5-FU) were evaluated using ovarian mucinous cancer cell lines.

RESULTS

The correlation of CDX2 with Reg IV expression was demonstrated in ovarian mucinous carcinoma. Reg IV expression was enhanced by transfection of CDX2 and was suppressed by inhibition of CDX2 expression. OMC-3 cells with ectopically overexpressed CDX2 showed enhanced apoptosis and sensitivity to 5-FU.

CONCLUSION

CDX2 promotes resistance to paclitaxel and sensitivity to 5-FU. Novel 5-FU-based chemotherapy based on CDX2 may be used in ovarian mucinous carcinoma.

Efficacy and safety of neoadjuvant chemotherapy versus primary debulking surgery in patients with ovarian cancer: a meta-analysis

OBJECTIVE

Neoadjuvant chemotherapy (NACT) for the treatment of epithelial ovarian cancer (EOC) has remained controversial. This meta-analysis was performed to systematically assess the efficacy and safety of NACT versus primary debulking surgery (PDS) in patients with EOC.

METHODS

PubMed, Embase, ClinicalTrials.gov, and Cochrane Library were queried to assess the therapeutic value of NACT versus PDS in EOC. Electronic databases were queried by using the keywords "ovarian cancer/neoplasms", "primary debulking surgery", and "neoadjuvant chemotherapy".

RESULTS

The available trials were pooled, and hazard ratios (HRs), relative risk ratios (RRs) and associated 95% confidence intervals (95% CIs) were determined. Sixteen trials involving 57,450 participants with EOC (NACT, 9,475; PDS, 47,975) were evaluated. We found that NACT resulted in markedly decreased overall survival than PDS in patients with EOC (HR=1.30; 95% CI=1.13-1.49; heterogeneity: p<0.001, I²=82.7%). Furthermore, our results demonstrated that the NACT group displayed increased completeness of debulking removal (RR=1.69, 95% CI=1.32-2.17; heterogeneity: p<0.001, I²=81.9%), and reduced risk of postsurgical death (RR=0.18, 95% CI=0.06-0.51; heterogeneity: p=0.698, I²=0%) and major infection (RR=0.29, 95% CI=0.17-0.51; heterogeneity: p=0.777, I²=0%) compared with patients administered PDS.

CONCLUSIONS

This meta-analysis indicated that NACT results in increased completeness of debulking removal, and reduced risk of postsurgical death and major infection compared with PDS, while PDS is associated with improved survival in comparison with NACT in EOC patients.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42019120625.

α-Pinene Induces Apoptotic Cell Death via Caspase Activation in Human Ovarian Cancer Cells

BACKGROUND The plant-derived terpenoid, alpha-pinene is a bicyclic monoterpene potentially useful for the treatment of various diseases which also includes cancer and its types. The present investigation is about finding the anticancer activity of the alpha-pinene extracted from the leaves of Boswellia dalzielii over the PA-1 cancer cells of the human ovary. MATERIAL AND METHODS The cytotoxic activity of the alpha-pinene was evaluated using MTT and LDH assays which indicated that alpha-pinene could induce cytotoxicity in cancer-causing cells in the ovary. The consequences of alpha-pinene on the cell sequence regulation were determined by the staining technique using propidium iodide (PI) followed with flow cytometry. RESULTS The cell cycle distribution analysis showed that alpha-pinene inhibit the cycle progression from G₂ to M phase. In addition, apoptosis analysis is done through the double staining investigation using Annexin V-FITC/PI to analyze the controlled growth of alpha-pinene which is associated with the apoptosis. Caspase-3 a crucial enzyme involved in apoptosis was markedly increased in the a-pinene treated PA-1 cells. The apoptosis results reveal, that the cancer cells at the human ovary with alpha-pinene induces the significant populations of apoptotic cells. CONCLUSIONS Overall, alpha-pinene may exert anticancer effects in PA-1 cells by promoting cytotoxicity, suppression of cell sequence progression along with the programmed cell death.

Presence and role of stem cells in ovarian cancer

Ovarian cancer is the deadliest gynecological malignancy. It is typically diagnosed at advanced stages of the disease, with metastatic sites disseminated widely within the abdominal cavity. Ovarian cancer treatment is challenging due to high disease recurrence and further complicated pursuant to acquired chemoresistance. Cancer stem cell (CSC) theory proposes that both tumor development and progression are driven by undifferentiated stem cells capable of self-renewal and tumor-initiation. The most recent evidence revealed that CSCs in terms of ovarian cancer are not only responsible for primary tumor growth, metastasis and relapse of disease, but also for the development of chemoresistance. As the elimination of this cell population is critical for increasing treatment success, a deeper understanding of ovarian CSCs pathobiology, including epithelial-mesenchymal transition, signaling pathways and tumor microenvironment, is needed. Finally, before introducing new therapeutic agents for ovarian cancer, targeting CSCs, accurate identification of different ovarian stem cell subpopulations, including the very small embryonic-like stem cells suggested as progenitors, is necessary. To these ends, reliable markers of ovarian CSCs should be identified. In this review, we present the current knowledge and a critical discussion concerning ovarian CSCs and their clinical role.

Overexpression of miR-148a inhibits viability and invasion of ovarian cancer OVCAR3 cells by targeting FOXO3

Decreased expression of microRNA (miR)-148a is associated with poor prognosis in ovarian cancer. The aim of the present study was to investigate the impact of miR-148a on tumor cell viability and invasion via targeting forkhead box protein O3 (FOXO3). Expression of miR-148a was detected in paired tumor and adjacent normal tissues. OVCAR3 cells were transfected with miR-148a mimic and inhibitor. Cell viability, apoptosis and invasion were determined. A luciferase reporter assay was used to study the association between miR-148a and FOXO3. In addition, the influence of miR-148a on tumor cell growth was investigated by performing xenograft assays in nude mice. RT-qPCR showed that miR-148a was downregulated in ovarian cancer tissues. Overexpression of miR-148a in OVCAR3 cells inhibited cell viability, suppressed invasion and promoted cellular apoptosis. The dual-luciferase assay indicated that miR-148a directly regulated the expression of FOXO3, a transcription factor of caspase-3. Western blotting confirmed that the expression of caspase-3 was regulated by the modulation of miR-148a expression. In vivo assays revealed that miR-148a overexpression inhibited the growth of OVCAR3 ×enograft tumors in nude mice. miR-148a is a tumor suppressor in ovarian cancer OVCAR3 cells and in nude mice. The suppressive effect is due to inhibiting cell viability and invasion as well as promoting apoptosis. These results may provide theoretical basis for targeting miR-148a in the treatment of ovarian cancer.

Mitochondrial Involvement in Cisplatin Resistance

Cisplatin is one of the worldwide anticancer drugs and, despite its toxicity and frequent recurrence of resistance phenomena, it still remains the only therapeutic option for several tumors. Circumventing cisplatin resistance remains, therefore, a major goal for clinical therapy and represents a challenge for scientific research. Recent studies have brought to light the fundamental role of mitochondria in onset, progression, and metastasis of cancer, as well as its importance in the resistance to chemotherapy. The aim of this review is to give an overview of the current knowledge about the implication of mitochondria in cisplatin resistance and on the recent development in this research field. Recent studies have highlighted the role of mitochondrial DNA alterations in onset of resistance phenomena, being related both to redox balance alterations and to signal crosstalk with the nucleus, allowing a rewiring of cell metabolism. Moreover, an important role of the mitochondrial dynamics in the adaptation mechanism of cancer cells to challenging environment has been revealed. Giving bioenergetic plasticity to tumor cells, mitochondria allow cells to evade death pathways in stressful conditions, including chemotherapy. So far, even if the central role of mitochondria is recognized, little is known about the specific mechanisms implicated in the resistance. Nevertheless, mitochondria appear to be promising pharmacological targets for overcoming cisplatin resistance, but further studies are necessary.

Paclitaxel-Induced Src Activation Is Inhibited by Dasatinib Treatment, Independently of Cancer Stem Cell Properties, in a Mouse Model of Ovarian Cancer

Approximately seventy percent of ovarian cancer patients succumb to the disease within the first 5 years of diagnosis, even after successful surgery and effective chemotherapy treatment. A small subset of chemotherapy resistant cancer stem cells (CSCs) cause relapse of ovarian cancers. This study investigated the association between paclitaxel-mediated Src activation (p-Src) and CSC populations in driving ovarian cancer progression. We demonstrate that patients with high-stage serous ovarian carcinomas have significantly elevated levels of p-Src, compared to patient with low-stage and benign ovarian tumours. Additionally, p-Src was significantly enhanced in ascites-derived tumour cells obtained from recurrent patients, compared to chemonaïve patients. Paclitaxel treatment increased Src activation in ovarian cancer cells, causing enrichment of CSC marker expression in the surviving cells in vitro and in xenografts of nude mice. Dasatinib in combination with paclitaxel significantly suppressed p-Src in ovarian cancer cell lines and xenografts but had no effect on the expression of CSC markers. However, combination of paclitaxel and Dasatinib showed lower trend in invasion in liver and pancreas, compared to paclitaxel-only treatment. The tumours treated with combination therapy also had significantly lower infiltration of mononuclear cells. Robust recurrent tumour growth was observed in all mice groups after termination of treatments. The above results suggest that Dasatinib-mediated inhibition of p-Src may not be crucial for paclitaxel-induced CSC-mediated recurrence in ovarian cancer.

BTB and CNC homology 1 (Bach1) promotes human ovarian cancer cell metastasis by HMGA2-mediated epithelial-mesenchymal transition

Transcriptional factor BTB and CNC homology 1 (Bach1) has been linked to tumor progression and metastasis, but the mechanisms underlying the effects of Bach1 on tumor growth and metastasis are largely uncharacterized. Here, we report that Bach1 expression was significantly higher in human epithelial ovarian cancer (EOC) tissues than in normal ovarian tissues and that higher levels of Bach1 were associated with tumor stage and poorer overall and progression-free survival. We found that Bach1 enhanced the expression of epithelial-mesenchymal transition (EMT) genes, including Slug and Snail, and promoted cell migration by recruiting HMGA2 in the human EOC cell line A2780. Bach1 overexpression enhanced and Bach1 knockout reduced the expression of Slug and the metastasis of EOC cells in a tumor metastasis mouse model. Bach1 expression was positively correlated with Slug and HMGA2 expression in human ovarian cancer tissues. In addition, Bach1 activated p-AKT and p-p70S6K, increased the expression of cyclin D1, and promoted the growth of ovarian cancer cells in vitro and tumor xenografts in vivo. Together, our findings reveal that Bach1 enhances tumor growth and recruits HMGA2 to promote EMT and ovarian cancer metastasis.

18F-FDG-PET/CT-guided intensity-modulated radiotherapy for 42 FIGO III/IV ovarian cancer: A retrospective study

The aim of the present study was to evaluate the curative effect of fludeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT)-guided intensity-modulated radiotherapy (IMRT) for 42 patients with International Federation of Gynecology and Obstetrics (FIGO) stage III/IV ovarian cancer. Between January 2012 and December 2015, 42 patients with FIGO stage III/IV ovarian cancer who were treated with 18F-FDG-PET/CT-guided IMRT at the Department of Radiation Oncology were analyzed. A total of 21 patients who exhibited recurrence following surgery and 11 patients who were unable to tolerate or rejected surgery received 5-10 cycles of chemotherapy only. A total of 10 patients, who were either older (>70 years) or in poor general health were unable to undergo surgery and only received IMRT. The patients received a total radiation dose of 5,040 cGy (range, 4,500-5,500 cGy), with a dose fraction of 200 cGy/fx, administered a total of 10-14 times, 5 times/week, prior to being rested for half an hour to relocate lesions and undergoing a second round of radiotherapy for 10-14 cycles. The 1-, 2- and 3-year progression-free survival (PFS) rates of the patients were 66.7, 33.3 and 21.4%, respectively, and the median PFS time was 20.3 months. The 1-, 2- and 3-year local control rates of the patients were 90.5, 83.3 and 69.0%, respectively, and the 1-, 2- and 3-year overall survival (OS) rates were 73.8, 64.3 and 52.4%, respectively. According to the results of multivariate analysis using the Cox proportional hazards model, the Karnofsky performance status (KPS) score (1) was the only index associated with prognosis (P<0.003). The study concluded that for patients with advanced ovarian cancer, particularly for patients unable to undergo surgery or chemotherapy, 18F-FDG PET/CT-guided IMRT is a safe and effective treatment method, and it may be considered as an equally effective treatment option. Furthermore, the results of the present study suggested that the KPS score of a patient is the only factor affecting the OS time.

Human Wharton's Jelly Stem Cell (hWJSC) Extracts Inhibit Ovarian Cancer Cell Lines OVCAR3 and SKOV3 in vitro by Inducing Cell Cycle Arrest and Apoptosis

Ovarian cancer is a highly lethal and the second highest in mortality among gynecological cancers. Stem cells either naïve or engineered are reported to inhibit various human cancers in both in-vitro and in-vivo. Herein we report the cancer inhibitory properties of human Wharton's jelly stem cell (hWJSC) extracts, namely its conditioned medium (hWJSC-CM) and cell lysate (hWJSC-CL) against two ovarian cancer cell lines (OVCAR3 and SKOV3) in-vitro. Cell metabolic activity assay of OVCAR3 and SKOV3 cells treated with hWJSC-CM (12.5, 25, 50, 75, 100%) and hWJSC-CL (5, 10, 15, 30, and 50 μg/ml) demonstrated concentration dependent inhibition at 24-72 h. Morphological analysis of OVCAR3 and SKOV3 cells treated with hWJSC-CM (50, 75, 100%) and hWJSC-CL (15, 30, and 50 μg/ml) for 24-72 h showed cell shrinkage, membrane damage/blebbings and cell death. Cell cycle assay demonstrated an increase in the sub-G1 and G2M phases of cell cycle following treatment with hWJSC-CM (50, 75, 100%) and hWJSC-CL (10, 15, and 30 μg/ml) at 48 h. Both OVCAR3 and SKOV3 cells demonstrated mild positive expression of activated caspase 3 following treatment with hWJSC-CM (50%) and hWJSC-CL (15 μg/ml) for 24 h. Cell migration of OVCAR3 and SKOV3 cells were inhibited following treatment with hWJSC-CM (50%) and hWJSC-CL (15 μg/ml) for 48 h. Tumor spheres (TS) of OVCAR3 and SKOV3 treated with hWJSC-CM (50, 75, 100%) and hWJSC-CL (10, 15, 30 μg/ml) for 48 h showed altered surface changes including vacuolations and reduction in size of TS. TS of OVCAR3 and SKOV3 also showed the presence of few ovarian cancer stem cells (CSCs) in minimal numbers following treatment with hWJSC-CM (50%) or hWJSC-CL (15 μg/ml) for 48 h. Real-time gene expression analysis of OVCAR3 and SKOV3 treated with hWJSC-CM (50%) or hWJSC-CL (15 μg/ml) for 48 h demonstrated decreased expression of cell cycle regulatory genes (cyclin A2, Cyclin E1), prostaglandin receptor signaling genes (EP2, EP4) and the pro-inflmmatory genes (IL-6, TNF-α) compared to untreated controls. The results indicate that hWJSC-CM and hWJSC-CL inhibit ovarian cancer cells at mild to moderate levels by inducing cellular changes, cell cycle arrest, apoptosis, decreasing the expression of CSC markers and related genes regulation. Therefore, the stem cell factors in hWJSCs extracts can be useful in cancer management.

The Experience of Being Aware of Disease Status in Women with Recurrent Ovarian Cancer: A Phenomenological Study

BACKGROUND

Awareness of disease status has been identified as a factor in the treatment decision-making process. Women with recurrent ovarian cancer are facing the challenge of making treatment decisions throughout the disease trajectory. It is not understood how women with ovarian cancer perceive their disease and subsequently make treatment decisions.

PURPOSE

The purpose of this phenomenological study was to understand the lived experience of women with recurrent ovarian cancer, how they understood their disease and made their treatment decisions.

METHODS

A qualitative design with a descriptive phenomenological method was used to conduct 2 in-depth interviews with 12 women (n = 24 interviews). Each interview was ∼60 minutes and was digitally recorded and professionally transcribed. Data collection focused on patients' understanding of their disease and how patients participated in treatment decisions. A modified version of Colaizzi's method of phenomenological reduction guided data analysis.

RESULTS

Three themes emerged to describe the phenomenon of being aware of disease status: (1) perceiving recurrent ovarian cancer as a chronic illness, (2) perceived inability to make treatment decisions, and (3) enduring emotional distress.

CONCLUSIONS AND IMPLICATIONS

This study revealed how 12 women conceptualized recurrent ovarian cancer as a chronic disease and their perceived inability to make treatment decisions because of lack of information and professional qualifications, resulting in enduring emotional distress. Future research should replicate the study to confirm the persistence of the themes for racially, ethnically, and religiously diverse patient samples and to improve understanding of awareness of disease status and decision-making processes of patients.

Association between dietary fiber intake and risk of ovarian cancer: a meta-analysis of observational studies

Objective

To evaluate the associations between dietary fiber intake and ovarian cancer risk.

Methods

A literature survey was conducted by searching the PubMed, Web of Science, and Wanfang Med Online databases up to March 1st, 2018. The effect of dietary fiber intake on ovarian cancer risk was evaluated by calculating relative risks with 95% confidence intervals (95%CI) using Stata 12.0 software.

Results

A total of 17 articles with 149,177 participants including 7609 ovarian cancer patients were included in this analysis. The summarized relative risk for ovarian cancer in participants with the highest compared with the lowest fiber intake was 0.760 (95%CI=0.702–0.823), with no significant between-study heterogeneity (I²=12.4%). Subgroup analysis according to study design demonstrated positive associations in both cohort studies and case-control studies. Moreover, the results were consistent among populations from America, Europe, and Asia. No publication bias was found by Egger’s test or funnel plots.

Conclusion

This meta-analysis concluded that a high intake of dietary fiber could significantly reduce the risk of ovarian cancer compared with a low fiber intake.

Residual tumour less than 0.25 centimetres and positive lymph nodes are risk factors for early relapse in recurrent ovarian peritoneal carcinomatosis treated with cytoreductive surgery, HIPEC and systemic chemotherapy

AIM

The cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has showed promising results for the survival in patients with recurrent ovarian carcinomatosis, however, some of them will recur within the first year. The aim of this study is focussed on identifying the risk factors to develop the recurrence within the first year after an optimal CRS-HIPEC in patients with recurrent ovarian carcinomatosis.

METHODS

A total of 100 patients with peritoneal carcinomatosis from recurrent ovarian cancer treated by CRS + HIPEC were selected for analysis. Multivariate logistic regression analysis was performed to evaluate the relationship between the variables and the early recurrence.

RESULTS

The mean follow-up was 42.5 months. The mean age was 56.2 years. Early recurrence was observed in the 36%. The group early recurrence presented a higher rate of optimal cytoreductions CC1 (16.2% vs. 3.5%), lymph nodes (32.5% vs. 15%) and the use of hemoderivates (40.5% vs. 33%). Others parameters as Peritoneal Cancer Index, major morbidity? 3, re-operations rate and time to adjuvant chemotherapy were similar in both groups. The five years OS was 58%, for the non-early recurrence was higher than the early recurrence group (64% vs. 41%). In the multivariate analysis, CC-1 (OR 5.73; 1.16-32.04) and positive lymph nodes (OR 2.26; 1.01-4.32) proved to be independent factors for the early recurrence.

CONCLUSION

The combination of both (CC1 and positive lymph nodes) makes that the indication of CRS and HIPEC should be individualised. However, the major morbidity, stage IV and the time to the adjuvant treatment were not associated with an early recurrence, so that, a major aggressiveness is recommended to achieve a CC0.

The Role of Inflammation and Inflammatory Mediators in the Development, Progression, Metastasis, and Chemoresistance of Epithelial Ovarian Cancer

Inflammation plays a role in the initiation and development of many types of cancers, including epithelial ovarian cancer (EOC) and high grade serous ovarian cancer (HGSC), a type of EOC. There are connections between EOC and both peritoneal and ovulation-induced inflammation. Additionally, EOCs have an inflammatory component that contributes to their progression. At sites of inflammation, epithelial cells are exposed to increased levels of inflammatory mediators such as reactive oxygen species, cytokines, prostaglandins, and growth factors that contribute to increased cell division, and genetic and epigenetic changes. These exposure-induced changes promote excessive cell proliferation, increased survival, malignant transformation, and cancer development. Furthermore, the pro-inflammatory tumor microenvironment environment (TME) contributes to EOC metastasis and chemoresistance. In this review we will discuss the roles inflammation and inflammatory mediators play in the development, progression, metastasis, and chemoresistance of EOC.

Can Stemness and Chemoresistance Be Therapeutically Targeted via Signaling Pathways in Ovarian Cancer?

Ovarian cancer is the most lethal gynecological malignancy. Poor overall survival, particularly for patients with high grade serous (HGS) ovarian cancer, is often attributed to late stage at diagnosis and relapse following chemotherapy. HGS ovarian cancer is a heterogenous disease in that few genes are consistently mutated between patients. Additionally, HGS ovarian cancer is characterized by high genomic instability. For these reasons, personalized approaches may be necessary for effective treatment and cure. Understanding the molecular mechanisms that contribute to tumor metastasis and chemoresistance are essential to improve survival rates. One favored model for tumor metastasis and chemoresistance is the cancer stem cell (CSC) model. CSCs are cells with enhanced self-renewal properties that are enriched following chemotherapy. Elimination of this cell population is thought to be a mechanism to increase therapeutic response. Therefore, accurate identification of stem cell populations that are most clinically relevant is necessary. While many CSC identifiers (ALDH, OCT4, CD133, and side population) have been established, it is still not clear which population(s) will be most beneficial to target in patients. Therefore, there is a critical need to characterize CSCs with reliable markers and find their weaknesses that will make the CSCs amenable to therapy. Many signaling pathways are implicated for their roles in CSC initiation and maintenance. Therapeutically targeting pathways needed for CSC initiation or maintenance may be an effective way of treating HGS ovarian cancer patients. In conclusion, the prognosis for HGS ovarian cancer may be improved by combining CSC phenotyping with targeted therapies for pathways involved in CSC maintenance.

Euxanthone inhibits glycolysis and triggers mitochondria-mediated apoptosis by targeting hexokinase 2 in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is one of the most prevalent gynaecological cancers. Euxanthone, an active ingredient of the medicinal plant Polygala caudata, exhibits a selective cytotoxic effect in tumour cells. The present study was aimed to determine whether euxanthone could suppress ovarian tumour growth, and to study the relevant mechanism. Two EOC cell lines, SKOV3 and A2780, were used as the in vitro model and treated with euxanthone. Cell viability and apoptosis were assayed using Cell Counting Kit-8 (CCK-8) and Annexin-V FITC/PI staining, respectively. Commercially available kits were used to measure the glucose consumption, lactate production, and intracellular ATP levels. Western blots assay was conducted to examine the level of apoptotic markers. To examine the roles of HK2 and STAT3 in the anti-tumour effect of euxanthone, cells were transfected with vectors overexpressing HK2 or STAT3, and assayed as above. Finally, SKOV3 cells were injected to mice models to appreciate the anti-neoplastic effect of euxanthone in vivo. We found that euxanthone impaired the cell viability and induced apoptosis via the intrinsic pathway in a concentration-dependent fashion in both SKOV3 and A2780 cells. Euxanthone also caused inhibition of glycolysis. Apoptosis and glycolysis inhibition was mediated by the downregulation of HK2, which in turn was a result of STAT3 inactivation. In vivo experiments also supported that euxanthone could exert anti-cancer activities without general toxicity. In conclusion, euxanthone triggered mitochondrial apoptosis and inhibited glycolysis in EOC cells.

SIGNIFICANCE OF THE STUDY

Euxanthone triggered mitochondrial apoptosis and inhibited glycolysis in EOC cells. Our findings provide preliminary experimental data that support further studies on the potential therapeutic role of euxanthone in ovarian cancer.

High WAVE3 expression correlates with proliferation, migration and invasion in human ovarian cancer

BACKGROUND

Wiskott-Aldrich syndrome verprolin-homologous (WAVE) 3, a member of the WASP/WAVE family of proteins, plays a critical role in cell motility and acts as an oncogene in some human cancers, but no sufficient information available to illustrate its involvement in ovarian cancer tumorigenesis and progression.

METHODS

The expression of WAVE3 in human ovarian cancer and normal tissue was analyzed by immunohistochemistry. WAVE3 gene and protein expression in different human ovarian cancer cell lines was tested by RT-PCR and western blotting. Stable cells of WAVE3-knockdown in SKOV3 cells or transfected high expression in A2780 cells were constructed. The WAVE3 expression and its correlation with MMPs, p38 MAPK and other factors were studied. The relationship between WAVE3 and oncogenicity in vivo was also evaluated by nude mice xenograft model.

RESULTS

Immunohistochemistry staining showed the highest WAVE3 expression in ovarian cancer metastases, high in ovarian cancer and weak in normal. In different cell lines, SKOV3 cells showed the highest WAVE3 expression, A2780 cells expressed the lowest. Elevated WAVE3 expression in A2780 cells promoted proliferation and decreased apoptosis, increased the cell number in G2/M phase and promoted migration significantly. Correspondingly, knockdown of WAVE3 in SKOV3 cells showed opposite effects. The WAVE3 expression showed positive correlation with MMPs, NF-κB, COX-2, VEGF and phospho-p38 MAPK, but not p38. The high expression of WAVE3 promoted tumorigenesis in vivo.

CONCLUSIONS

Our results suggested that WAVE3 may be pivotal in ovarian cancer cell motility, invasion and oncogenesis, which might be related with MMPs production and p38 MAPK pathway.

Anticancer activity of the intraperitoneal-delivered DFP-10825, the cationic liposome-conjugated RNAi molecule targeting thymidylate synthase, on peritoneal disseminated ovarian cancer xenograft model

Introduction

Peritoneal disseminated ovarian cancer is one of the most difficult cancers to treat with conventional anti-cancer drugs and the treatment options are very limited, although an intraperitoneal (ip) paclitaxel has shown some clinical benefit. Therefore, treatment of peritoneal disseminated ovarian cancer is a highly unmet medical need and it is urgent to develop a new ip delivered drug regulating the fast DNA synthesis.

Methods

We developed a unique RNAi molecule consisting of shRNA against the thymidylate synthase (TS) and a cationic liposome (DFP-10825) and tested its antitumor activity and PK profile in peritoneally disseminated human ovarian cancer ascites models by the luciferase gene-transfected SCID mice. DFP-10825 alone, paclitaxel alone or combination with DFP-10825 and paclitaxel were administered in an ip route to the tumor-bearing mice. The TS expression level was measured by conventional RT-PCR. The anti-tumor activity and host survival benefit by DFP-10825 treatment on tumor-bearing mice were observed as resulting from the specific TS mRNA knock-down in tumors.

Results

DFP-10825 alone significantly suppressed the growth of SKOV3-luc tumore ascites cells and further extended the survival time of these tumor-bearing mice. Combination with the ip paclitaxel augmented the antitumor efficacy of DFP-10825 and significantly prolonged the survival time in the tumor-bearing mice. Short-hairpin RNA for TS (TS shRNA) levels derived from DFP-10825 in the ascetic fluid were maintained at a nM range across 24 hours but not detected in the plasma, suggesting that TS shRNA is relatively stable in the peritoneal cavity, to be able to exert its anti-tumor activity, but not in blood stream, indicating little or no systemic effect.

Conclusion

Collectively, the ip delivery of DFP-10825, TS shRNA conjugated with cationic liposome, shows a favorable antitumor activity without systemic adverse events via the stable localization of TS shRNA for a sufficient time and concentration in the peritoneal cavity of the peritoneally disseminated human ovarian cancer-bearing mice.

Targeting epithelial-mesenchymal transition and cancer stem cells for chemoresistant ovarian cancer

Chemoresistance is the main challenge for the recurrent ovarian cancer therapy and responsible for treatment failure and unfavorable clinical outcome. Understanding mechanisms of chemoresistance in ovarian cancer would help to predict disease progression, develop new therapies and personalize systemic therapy. In the last decade, accumulating evidence demonstrates that epithelial-mesenchymal transition and cancer stem cells play important roles in ovarian cancer chemoresistance and metastasis. Treatment of epithelial-mesenchymal transition and cancer stem cells holds promise for improving current ovarian cancer therapies and prolonging the survival of recurrent ovarian cancer patients in the future. In this review, we focus on the role of epithelial-mesenchymal transition and cancer stem cells in ovarian cancer chemoresistance and explore the therapeutic implications for developing epithelial-mesenchymal transition and cancer stem cells associated therapies for future ovarian cancer treatment.

Clinical significance and prognostic value of Forkhead box A1 expression in human epithelial ovarian cancer

Forkhead box (FOX) A1 is a member of the FOX family of transcription factors, which serve a function in numerous types of tumor. The present study assessed the potential role of FOXA1 in human epithelial ovarian carcinoma (EOC). Total RNA was isolated from 16 fresh-frozen EOC tumors with paired corresponding non-malignant ovarian epithelium tissues, and FOXA1 expression was analyzed using reverse transcription-quantitative polymerase chain reaction. Immunohistochemical analysis was performed to evaluate FOXA1 expression in 110 epithelial ovarian carcinoma tissue specimens (including 80 serous papillary adenocarcinoma, 9 clear cell carcinoma, 12 endometrioid adenocarcinoma, 5 mucinous carcinoma and 4 transitional cell carcinoma specimens), 24 benign ovarian tumor surface epithelium tissues and 10 normal ovarian tissue samples. The present study analyzed the association between FOXA1 expression and clinical characteristics in patients with EOC. The Kaplan-Meier method was used for survival analysis. The results of the present study revealed that FOXA1 mRNA expression was significantly increased in EOC tissues compared with paired normal ovarian samples (P=0.014). The immunohistochemical expression of FOXA1 in EOC tissues was associated with the FIGO grade, differentiation status and overall survival time (all P<0.05). Finally, the significance of FOXA1 expression in the prognosis of the patients was evaluated. The results of Kaplan-Meier survival curve revealed that high FOXA1 expression was associated with decreased overall survival time in the patients, relative to low FOXA1 expression (P=0.0132). In conclusion, FOXA1 is overexpressed in EOC and associated with clinicopathological features, including overall survival time. FOXA1 potentially represents a novel biomarker and therapeutic target for EOC.

Tumor-associated macrophages and the tumor immune microenvironment of primary and recurrent epithelial ovarian cancer

Tumor-infiltrating lymphocytes (TILs) are associated with better prognosis in newly diagnosed epithelial ovarian cancer (EOC), but clinical trials of immunotherapies in patients with heavily treated disease reveal limited activity. Understanding the tumor microenvironment (TME) of primary and recurrent EOC should guide future trials. Here, we evaluated the TME of paired primary and recurrent tumors (n = 17), and non-paired primary (n = 20) and recurrent (n = 15) tumors, for CD8+ T cells, FOXP3+ regulatory T cells (Tregs), CD68+ tumor-associated macrophages (TAMs), programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1). CD8+ T cells were similar in primary and recurrent tumors, but Tregs were higher in recurrent tumors (P = .0210). Higher TAM density (≥5%) associated with higher Tregs (P = .001) and CD8+ T cells (P < .001) in recurrent tumors, but only with higher Tregs in primary tumors (P = .02). TAM-dense recurrent tumors expressed PD-L1 on tumor and immune cells, whereas TAM-dense primary tumors expressed PD-L1 predominantly on immune cells. In survival analyses, higher Tregs in primary tumors correlated with decreased time to first recurrence (17.0 versus 28.5 months, P = .022). Conversely, higher Tregs in recurrent tumors correlated with longer overall survival (OS) from recurrence (median not met versus 20.0 months, P = .022). TAM density did not affect patient survival. However, patients with increased TAMs at recurrence (n = 5) had longer OS from recurrence compared to patients without increased TAMs (n = 12) (56.0 versus 20.0 months); with the small sample size, this did not reach statistical significance (P = .074). Further characterization of the evolution of the TME is warranted.

Amentoflavone suppresses tumor growth in ovarian cancer by modulating Skp2

AIM

Ovarian cancer is one of most common malignancies in women and is associated with high reoccurrence rate and poor prognosis. This study is designed to investigate the anti-tumor effects of amentoflavone (AF), one of the major active ingredients of S. tamariscina, against ovarian cancer.

MATERIALS AND METHODS

Human ovarian cancer cell lines SKOV3 and OVCAR-3 were used in this study. The effect of AF on cell viability was examined by CCK-8 assay. Cell apoptosis and cell cycle distribution was determined by flow cytometry. ROS generation was detected using fluorescent staining. Expression of signaling molecules was determined by western blots. Xenograft model was established to evaluate the therapeutic efficacy of AF in vivo.

KEY FINDINGS

Our results showed that AF could significantly suppress cell proliferation, induce apoptosis and block cell cycle progression. Mechanistically, downregulation of S-phase kinase protein 2 (Skp2) by AF contributed to its anti-tumor effect against ovarian cancer. Furthermore, our results showed that AF repressed the expression of Skp2 through ROS/AMPK/mTOR signaling. The anti-tumor effect of AF against ovarian cancer was also confirmed in a xenograft animal model.

SIGNIFICANCE

Overall, our present findings highlighted the potential of AF in the treatment of ovarian cancer. Moreover, our study also provided a new elucidation regarding the anti-tumor mechanisms of AF.

Docosahexaenoic Acid Modulates Invasion and Metastasis of Human Ovarian Cancer via Multiple Molecular Pathways

OBJECTIVE

We investigated the effect of docosahexaenoic acid (DHA) on the invasion and metastasis of ovarian cancer cells (A2780, HO8910, and SKOV-3).

METHODS

Cytotoxicity assay was performed to determine the optimal doses of DHA in this experiment. The effects of DHA on invasion ability were assessed by invasion assay. The expressions of messenger RNA and/or proteins associated with invasion or metastasis were detected by quantitative Real Time-Polymerase Chain Reaction or Western blot. The effect of DHA on cell metastasis was assessed in xenograft model of zebrafish.

RESULTS

Docosahexaenoic acid and α-linolenic acid could reduce the cell vitalities in dose-dependent manner. However, DHA inhibited the invasion and metastasis of ovarian cancer cells, but α-linolenic acid did not (**P < 0.01). Docosahexaenoic acid could downregulate the expressions of WAVE3, vascular endothelial cell growth factor, and MMP-9, and upregulate KISS-1, TIMP-1, and PPAR-γ, which negatively correlated with cell invasion and metastasis (*P < 0.05). Docosahexaenoic acid restrained the development of subintestinal vessels and cancer cell metastasis in xenograft model of zebrafish (**P < 0.01).

CONCLUSIONS

Docosahexaenoic acid inhibited the invasion and metastasis of ovarian cancer cells in vitro and in vivo through the modulation of NF-κB signaling pathway, suggesting that DHA is a promising candidate for ovarian cancer therapy.

Association between matrix metalloproteinases polymorphisms and ovarian cancer risk: A meta-analysis and systematic review

Background

Published data on the relationship between matrix metalloproteinases (MMPs) polymorphisms and ovarian cancer risk have implicated inconclusive results. To evaluate the role of MMPs polymorphisms in ovarian cancer risk, a meta-analysis and systematic review were performed.

Methods

MMPs polymorphisms which could be quantitatively synthesized were involved in meta-analysis. Five comparison models (homozygote model, heterozygote model, dominant model, recessive model, additive model) were carried out, a subgroup analysis was performed to clarify heterogeneity source. The remaining polymorphisms which could not be quantitatively synthesized were involved in systematic review.

Results

10 articles with 20 studies were included in this paper. Among those studies, 8 studies involving MMP1 rs1799750 and MMP3 rs34093618 could be meta-analyzed and 12 studies involving 12 polymorphisms could not. Meta-analysis showed that no associations were found between MMP1 rs1799750 (homozygote model: OR = 0.93, 95%CI = 0.70–1.23, P_OR = 0.60; heterozygote model: OR = 1.09, 95%CI = 0.78–1.54, P_OR = 0.61; dominant model: OR = 1.02, 95%CI = 0.83–1.25, P_OR = 0.84; recessive model: OR = 0.95, 95%CI = 0.75–1.21, P_OR = 0.67; additive model: OR = 1.00, 95%CI = 0.85–1.17, P_OR = 0.99), MMP3 rs34093618 (homozygote model: OR = 1.25, 95%CI = 0.70–2.24, P_OR = 0.46; heterozygote model: OR = 1.08, 95%CI = 0.51–2.31, P_OR = 0.84; dominant model: OR = 0.97, 95%CI = 0.68–1.38, P_OR = 0.85; recessive model: OR = 1.12, 95%CI = 0.69–1.80, P_OR = 0.65; additive model: OR = 1.01, 95%CI = 0.79–1.31, P_OR = 0.91) and ovarian cancer. Furthermore, similar results were detected in subgroup analysis. The systematic review on 12 polymorphisms suggested that MMP2 C-735T, MMP7 A-181G, MMP8 rs11225395, MMP9 rs6094237, MMP12 rs2276109, MMP20 rs2292730, MMP20 rs12278250, MMP20 rs9787933 might have a potential effect on ovarian cancer risk.

Conclusions

In summary, polymorphisms of MMPs might not be associated with ovarian cancer risk. However, it is necessary to conduct more larger-scale, multicenter, and high-quality studies in the future.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for the treatment of advanced epithelial and recurrent ovarian carcinoma: a single center experience

BACKGROUND

With standard treatment of epithelial ovarian cancer (EOC), prognosis is very poor. The aim of this study is to show early and late results in patients who underwent cytoreductive surgery and intraperitoneal chemotherapy.

PATIENTS AND METHODS

This was a retrospective single centre study. All patients with advanced and recurrent ovarian cancer treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) or modified early postoperative intraperitoneal chemotherapy (EPIC) were included in the study.

RESULTS

In the period 1995-2014, 116 patients were treated, 55 with primary EOC and 61 with recurrent EOC. The mean age was 59 years (26-74). Statistically, median survival time was significantly longer in the group with primary advanced cancer of the ovary (41.3 months) compared to relapsed ovarian cancer (27.3 months). Survival for the primary EOC was 65 and 24% at 3 and 5 years, respectively. Survival for recurrent EOC was 33 and 16% at 3 and 5 years, respectively. Mortality was 1/116 (0.8%). Morbidity was 11/116 (9.5%). Peritoneal cancer index (PCI) was ≤20 in 59 (51%) patients and statistically, their average survival was significantly longer than in the group of 57 (49%) patients with PCI >20 (p = 0.014).

CONCLUSIONS

In advanced or recurrent EOC, a curative therapeutic approach was pursued that combined optimal cytoreductive surgery and intraperitoneal chemotherapy. PCI and timing of the intervention (primary or recurrent) were the strongest independent prognostic factors.

Prognostic value of HER-2/neu expression in epithelial ovarian cancer: a systematic review and meta-analysis

This study aimed to conduct a meta-analysis to investigate the association between human epidermal growth factor receptor 2 (HER-2/neu) expression and survival in patients with epithelial ovarian cancer (EOC). HER-2/neu is one of the most frequently studied molecular biological parameters in EOC, but its prognostic impact has not been fully assessed. PubMed and Embase were searched for studies that reported HER-2/neu expression and survival in patients with EOC. The primary outcome was overall survival (OS), and the secondary outcome was progression-free survival (PFS). Hazard ratios (HRs) with 95% confidence interval (CI) were determined using Mantel-Haenszel random-effects model. Publication bias was investigated using funnel plots and Egger's test. A total of 56 studies (N=7212) were included in the analysis. The results showed that patients possessing HER-2/neu expression had significant disadvantages in OS (HR = 1.41; 95%CI, 1.31 to 1.51; P < 0.001) and PFS (HR = 1.38; 95% CI, 1.23-1.56; P < 0.001). The trim-and-fill method, Copas model, and subgroup analyses stratified by the study characteristics confirmed the robustness of the results. The present study findings provided further indication that HER-2/neu expression in patients with EOC has an adverse impact on OS and PFS.

Autophagy inhibition reduces chemoresistance and tumorigenic potential of human ovarian cancer stem cells

Epithelial ovarian cancer (EOC) is one of the most malignant gynecological tumors with a high mortality rate owing to tumor relapse after anticancer therapies. It is widely accepted that a rare tumor cell population, known as cancer stem cells (CSC), is responsible for tumor progression and relapse; intriguingly, these cells are able to survive nutrient starvation (such as in vitro culture in the absence of glucose) and chemotherapy treatment. Recent data also indicated that chemotherapy resistance is associated with autophagy activation. We thus decided to investigate both in vitro and in vivo the autophagic activity and the effects of the perturbation of this pathway in CSC isolated from EOC ascitic effusions. Ovarian CSC, identified according to their CD44/CD117 co-expression, presented a higher basal autophagy compared with the non-stem counterpart. Inhibition of this pathway, by in vitro chloroquine treatment or CRISPR/Cas9 ATG5 knockout, impaired canonical CSC properties, such as viability, the ability to form spheroidal structures in vitro, and in vivo tumorigenic potential. In addition, autophagy inhibition showed a synergistic effect with carboplatin administration on both in vitro CSC properties and in vivo tumorigenic activity. On the whole, these results indicate that the autophagy process has a key role in CSC maintenance; inhibition of this pathway in combination with other chemotherapeutic approaches could represent a novel effective strategy to overcome drug resistance and tumor recurrence.

SIRT1 Regulates the Chemoresistance and Invasiveness of Ovarian Carcinoma Cells

BACKGROUND

SIRT1 is a longevity gene that forestalls aging and age-related diseases including cancer, and has recently attracted widespread attention due to its overexpression in some cancers. We previously identified the overexpression of SIRT1 in ovarian carcinoma (OvCa) as a poor prognostic factor. However, mechanistic insights into the function of SIRT1 in OvCa have yet to be elucidated.

METHODS

Quantitative real-time reverse PCR (qRT-PCR) and Western blotting were employed to examine the expression of SIRT1 in a panel of human OvCa cell lines. si-RNA or sh-RNA and cDNA technologies were utilized to knockdown or overexpress SIRT1, respectively. The effects of SIRT1 on proliferation and chemoresistance were examined using a WST-1 assay, and the underlying mechanisms were confirmed using an apoptotic assay, and the quantification of glutathione (GSH), and reactive oxygen species (ROS). The aggressiveness of SIRT1 was analyzed using in vitro invasion and migration assays.

RESULTS

SIRT1 was more strongly expressed in OvCa cell lines than in the immortalized ovarian epithelium at the gene and protein levels. Stress up-regulated the expression of SIRT1 in dose- and time-dependent manners. SIRT1 significantly enhanced the proliferation (P<.05), chemoresistance (P<.05), and aggressiveness of OvCa cells by up-regulating multiple antioxidant pathways to inhibit oxidative stress. Further study into the overexpression of SIRT1 demonstrated the up-regulation of several stemness-associated genes and enrichment of CD44v9 via an as-yet-unidentified pathway.

CONCLUSIONS

Our results suggest that SIRT1 plays a role in the acquisition of aggressiveness and chemoresistance by OvCa, and has potential as a therapeutic target for OvCa.

CD24 expression is a marker for predicting clinical outcome and regulates the epithelial-mesenchymal transition in ovarian cancer via both the Akt and ERK pathways

The degree of peritoneal dissemination and chemotherapy-resistant tumors is related to the prognosis in patients with advanced-stage ovarian cancer. The epithelial-mesenchymal-transition (EMT) is a multifaceted pathological program that endows cancer cells with the ability to invade and disseminate. CD24 is frequently overexpressed in various human cancers and is correlated with a poor prognosis. We herein examined the functions of CD24 in human ovarian cancer cell lines and evaluated how it contributes to the molecular mechanism underlying the regeneration of cancer stem-like cells (CSCs) through the EMT mechanism in ovarian carcinoma. We demonstrated that CD24 was expressed in 70.1% of primary ovarian carcinoma tissues, which were obtained from 174 patients, and that the expression of CD24 was an independent predictor of survival in patients with ovarian cancer. The expression of CD24 has been found to be correlated with the FIGO stage, presence of peritoneal and lymph node metastasis. CD24 induces the EMT phenomenon, which is involved in cell invasion, the highly proliferative phenotype, colony formation and which is associated with cisplatin resistance and the properties of CSCs, via the activation of PI3K/Akt, NF-κB and ERK in Caov-3 cisplatin-resistant cell lines. CD24-positive ovarian carcinomas have been shown to have a greater potential for intra-abdominal tumor cell dissemination in in vivo models. Our findings suggest that CD24 induced the EMT phenomenon in ovarian cancer, and that CD24 amplified cell growth-related intracellular signaling via the PI3K/Akt and MAPK pathways by affecting the EMT signal pathways. We believe that CD24 is a key molecule of metastatic progression in the EMT phenomenon and a promising therapeutic target for advanced ovarian cancer.

Epidemiology and treatment patterns of epithelial ovarian cancer

INTRODUCTION

While ovarian cancer (OC) is relatively rare, it remains one of the most fatal cancers. Lack of robust screening methods for eOC lead to detection of most cases at advanced stages, and most patients relapse following initial treatment. Areas covered: This review summarizes epidemiology and treatment patterns of epithelial ovarian cancer (eOC). MEDLINE, EMBASE, conference proceedings, and the Cochrane Library were searched using key terms and Medical Subject Headings for ovarian cancer, treatment patterns, and epidemiology to identify articles published from 2005-2015. Expert commentary: To improve early detection, future studies should focus on the identification of biomarkers that can detect asymptomatic disease. Following diagnosis and eventual relapse, response to first-line platinum appears to guide physicians' choice of subsequent therapies, but we do not understand what patients ultimately receive or its relationship to categories of response to first-line platinum. Improved understanding of later-line treatment patterns, by initial response to platinum, could correlate with overall outcomes among relapsed patients and promote development of more effective treatment guidelines. Novel treatment approaches, such as immunotherapies, would fulfill a need for an effective strategy against advanced stages of OC that results in fewer toxic side effects.

TET1 promotes cisplatin-resistance via demethylating the vimentin promoter in ovarian cancer

The development of chemo-resistance impairs the outcome of the first line platinum-based chemotherapies for ovarian cancer. Deregulation of DNA methylation/demethylation provides a critical mechanism for the occurrence of chemo-resistance. The ten-eleven translocation (TET) family of dioxygenases including TET1/2/3 plays an important part in DNA demethylation, but their roles in cisplatin resistance have not been elucidated. Using cisplatin-sensitive and cisplatin-resistant ovarian cancer cell models, we found that TET1 was significantly upregulated in cisplatin-resistant CP70 cells compared with that in cisplatin-sensitive A2780 cells. Ectopic expression of TET1 in A2780 cells promoted cisplatin resistance and decreased cytotoxicity induced by cisplatin, while inhibition of TET1 by siRNA transfection in CP70 cells attenuated cisplatin resistance and enhanced cytotoxicity of cisplatin. Increased TET1 induced re-expression of vimentin through active DNA demethylation, and cause partial epithelial-to-mesenchymal (EMT) in A2780 cells. Contrarily, knocking down of TET1 in CP70 cells reduced vimentin expression and reversed EMT process. Immunohistochemical analysis of TET1 in human ovarian cancer tissues revealed that TET1 existed in nucleus and cytoplasm in ovarian cancer tissues. And the expression of nuclear TET1 was positively correlated with residual tumor and chemotherapeutic response. Thus, TET1 expression causes resistance to cisplatin and one of the targets of TET1 action is vimentin in ovarian cancer.

A phase 1/2a, dose-escalation, safety, pharmacokinetic, and preliminary efficacy study of intraperitoneal administration of BC-819 (H19-DTA) in subjects with recurrent ovarian/peritoneal cancer

BACKGROUND

H19 is a paternally imprinted, oncofetal gene expressed in various embryonic tissues and in 85% of the ovarian tumors. H19-DTA (BC-819) is a DNA plasmid that drives the expression of the diphtheria toxin gene under the regulation of the H19 promoter sequence and therefore is a potential treatment for various tumors that overexpress the H19 gene, among them-ovarian cancer.

OBJECTIVE

To assess the safety and efficacy of intra-peritoneal (IP) instillations of H19-DTA (BC-819) plasmid in treating ovarian/peritoneal cancer patients with advanced recurrent disease.

METHODS

A phase 1-2A multi-centric trial included 14 eligible patients who were either platinum-refractory or platinum-resistant with positive H19 expression. Patients were treated IP with escalating weekly doses of BC-819 for a maximum of 6-9 weeks. Dose-limiting toxicities (DLT) were assessed after the first course of treatment for each patient and each subsequent cohort was enrolled once each subject had completed the first course of treatment and its 4-week follow-up period. The occurrence of adverse events (AEs) and response to treatment were assessed after the induction course and then periodically.

RESULTS

During the study, no DLTs were observed. Only 5 grade 1 and 2 AEs, which occurred in 4 patients were considered as possibly related to BC-819. The best tumor response seen was stable disease. Median survivals of 3.2, 5.3 and 6.5 months were observed for the 60, 120 and 240 mg cohorts, respectively.

CONCLUSIONS

BC-819 can be considered safe and well tolerated in intraperitoneal doses up to 240 mg. Hybridization of intraperitoneal chemotherapy with the biological treatment of BC-819 should be further evaluated in phase 2 and 3 studies.

BMI-1 interacts with sMEK1 and inactivates sMEK1-induced apoptotic cell death

The B lymphoma Mo-MLV insertion region 1 homolog (BMI-1) protein is activated in various types of tumors and associated with cancer development and tumor progression. However, the working role of BMI-1 in cellular signaling is not understood completely. In this study, we revealed one possible biologic mechanism of BMI-1 in cancer progression in vitro using a human ovarian tumor cell system. Suppressor of MEK1 (sMEK1), a pivotal regulator involved in the cellular biological response mechanism, was identified as a BMI-1-binding protein. Ectopic expression of BMI-1 activated cell growth by reducing sMEK1-stimulated apoptotic cell death and suppressing p21, p27 and p53 expression, while enhancing cyclin D1, CDK4 and Bcl-2 expression. The effect of BMI-1 on cell cycle and apoptotic regulatory proteins was also confirmed via silencing of BMI-1 expression. Subsequently, the promoter activities of p21 and p53 were inactivated significantly. However, BMI-1 overexpression noticeably increased Bcl-2 and NF-κB activities. In addition, BMI-1 activated the PI3K/mTOR/4E-BP1 signaling pathways, and sMEK1 significantly inhibited BMI-1-stimulated oncogenesis. These insights provide evidence that BMI-1 activates cell growth and suppresses apoptosis. Collectively, our data indicate that BMI-1 plays a pivotal role in the progression of ovarian cancer, thus representing a novel target for antitumor therapy of ovarian cancer.

The pro-inflammatory effect of obesity on high grade serous ovarian cancer

INTRODUCTION

Obesity is a known generator of chronic inflammation but has an uncertain role in ovarian carcinogenesis and survival. Pro-inflammatory cytokines have previously been associated with poor outcomes. Given the established links, we sought to determine whether obesity and pro-inflammatory cytokines affect platinum sensitivity.

METHODS

A retrospective review was performed of patients undergoing primary debulking surgery (PDS) for high grade serous ovarian cancer (HGSC) who had available pre-operative serum. Oncologic and treatment characteristics were recorded and analyzed using SAS version 9.3. Bioplex reagent kit was used to measure serum cytokine concentrations.

RESULTS

86 patients met study criteria. Most were Caucasian (88%) and non-diabetic (92%). All patients had advanced stage (III/IV) disease and received chemotherapy after PDS. In univariate analysis, lower VEGF (p=0.013) was associated with longer overall survival (OS). Low IL-8 level (p=0.053) was marginally associated with platinum resistant disease. After adjusting for covariates including residual disease and maintenance therapy, IL-8 was no longer associated with platinum sensitive status (p=0.13), VEGF remained associated with OS (low vs. high HR 0.3, 95% CI 0.1-0.8, p=0.018), and higher IL-12 was associated with longer PFS (HR 0.4, 95% CI 0.2-0.9, p=0.031).

CONCLUSION

In HGSC, pro-inflammatory cytokines are influenced by obesity, as differing inter-cytokine correlations were observed based on BMI, possibly due to dysregulation between cytokines in the setting of obesity. Differences in survival and platinum sensitivity were not noted. Future studies are warranted to determine whether obesity may be a modifiable risk factor for poorer outcomes due to differing immune response.

The effect of salinomycin on ovarian cancer stem-like cells

OBJECTIVE

The identification of cancer stem-like cells is a recent development in ovarian cancer. Compared to other cancer cells, cancer stem-like cells present more chemo-resistance and more aggressive characteristics. They play an important role in the recurrence and drug resistance of cancer. Therefore, the target therapy of cancer stem-like cell may become a promising and effective approach for ovarian cancer treatment. It may also help to provide novel diagnostic and therapeutic strategies.

METHODS

The OVCAR3 cell line was cultured under serum-free conditions to produce floating spheres. The CD44(+)CD117(+) cell line was isolated from the human ovarian cancer cell line OVCAR3 by using immune magnetic-activated cell sorting system. The expression of stemness genes such as OCT3/4, NANOG and SOX2 mRNA were determined by reverse transcription polymerase chain reaction. OVCAR3 parental and OVCAR3 CD44(+)CD117(+) cells were grown in different doses of paclitaxel and salinomycin to evaluate the effect of salinomycin. And growth inhibition of OVCAR3 CD44(+)CD117(+) cells by paclitaxel combined with salinomycin was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.

RESULTS

Tumor spheroids generated from the OVCAR3 cell line are shown to have highly enriched CD44 and CD117 expression. Treatment with a combination of paclitaxel and salinomycin demonstrated growth inhibition of OVCAR3 CD44(+)CD117(+) cells.

CONCLUSION

The present study is a detailed investigation on the expression of CD44 and CD117 in cancer stem cells and evaluates their specific tumorigenic characteristics in ovarian cancer. This study also demonstrates significant growth inhibition of cancer stem-like cells by paclitaxel combined with salinomycin. Identification of these cancer stem-like cell markers and growth inhibition effect of salinomycin may be the next step to the development of novel target therapy in ovarian cancer.

Biological characteristics of side population cells in a self-established human ovarian cancer cell line

The aim of the present study was to establish an ovarian cancer (OC) cell line from ascites of an ovarian serous cystadenocarcinoma patient and investigate the biological characteristics of its side population (SP) cells. The OC cell line was established by isolating, purifying and subculturing primary cells from ascites of an ovarian serous cystadenocarcinoma patient (stage IIIc; grade 3). SP and non-SP (NSP) cells were isolated by fluorescence-activated cell sorting and cultured in serum-free medium and soft agar to compare the tumorsphere and colony formation capacities. Furthermore, SP and NSP cell tumorigenesis was examined by subcutaneous and intraperitoneal injection of the cells to non-obese diabetic/severe combined immune deficiency (NOD/SCID) mice. Drug resistance to cisplatin was examined by cell counting kit-8. The OC cell line was successfully established from ascites of an ovarian serous cystadenocarcinoma patient, which exhibited properties similar to primary tumors subsequent to >50 passages and >2 years of culture. The SP cell ratio was 0.38% in the OC cell line, and a similar SP cell ratio (0.39%) was observed when sorted SP cells were cultured for 3 weeks. Compared with NSP cells, SP cells exhibited increased abilities in differentiation and tumorsphere and colony formation, in addition to the formation of xenografted tumors and ascites and metastasis of the tumors in NOD/SCID mice, even at low cell numbers (3.0×10³ cells). The xenografted tumors demonstrated histological features similar to primary tumors and expressed the ovarian serous cystadenocarcinoma marker CA125. In addition, SP cells demonstrated a significantly stronger drug resistance to cisplatin compared with NSP and unsorted cells, while treatment with verapamil, an inhibitor of ATP-binding cassette transporters, potently abrogated SP cell drug resistance. In conclusion, the present study verified SP cells from an established OC cell line and characterized the cells with self-renewal, differentiation, proliferation, tumorigenesis and stronger drug resistance capacities.

Delivery of siRNA to ovarian cancer cells using laser-activated carbon nanoparticles

AIM

The RNAi-mediated knockdown of gene expression is an attractive tool for research and therapeutic purposes but its implementation is challenging. Here we report on a new method based on photoacoustic delivery of siRNA developed to address some of these challenges.

MATERIALS & METHODS

Physical properties and photoacoustic emission of carbon black (CB) particles upon near-infrared laser irradiation were characterized. Next, ovarian cancer cells Hey A8-F8 were exposed to near-infrared nanosecond laser pulses in the presence of siRNA targeting EGFR gene and CB particles. The intracellular delivery of siRNA and silencing of the target gene were determined by specific qPCR assays.

RESULTS & CONCLUSION

Laser-activated CB nanoparticles generated photoacoustic emission and enabled intracellular delivery of siRNA and significant knockdown of its target EGFR mRNA. This physical method represents a new promising approach to targeted therapeutic delivery of siRNA.

Regulation of multidrug resistance 1 expression by CDX2 in ovarian mucinous adenocarcinoma

Epithelial ovarian cancer is an aggressive gynecological malignancy with a high mortality rate. Resistance against chemotherapeutic agents often develops in ovarian cancer patients, contributing to high recurrence rates. The multidrug resistance 1 (MDR1/ABCB1) gene encodes P‐glycoprotein, which affects the pharmacokinetic properties of anticancer agents. We previously reported that the Caudal‐related homeobox transcription factor CDX2 transcriptionally regulates MDR1 expression in colorectal cancer. CDX2 is a factor that influences cancer cell differentiation, malignancy, and cancer progression. We hypothesized that profiling of CDX2 and MDR1 expression could be an effective strategy for predicting anticancer drug resistance. We studied the expression of these factors in clinical samples from ovarian cancer patients. We found that endogenous MDR1 expression was positively associated with CDX2 expression in ovarian mucinous adenocarcinoma. Using ovarian mucinous adenocarcinoma cell lines, we also observed decreased MDR1 expression following inhibition of CDX2 by RNA interference. In addition, CDX2 overexpression in MN‐1 cells, which display low endogenous CDX2, resulted in upregulation of MDR1 expression. CDX2 induced MDR1‐dependent resistance to vincristine and paclitaxel, which was reversed by treatment with the MDR1‐specific inhibitor verapamil. Our findings show that CDX2 promotes upregulation of MDR1 expression, leading to drug resistance in ovarian mucinous adenocarcinoma. Therefore, our study demonstrates the potential of novel chemotherapy regimens based on CDX2 status and MDR1 expression in ovarian mucinous adenocarcinoma.