Management of recurrent ovarian carcinoma: current status and future directions

Comprehensive Network Analysis of Dysregulated Genes Revealed MNX1‐AS1/ hsa‐miR‐4697‐3p/ HOXB13 Axis in OC Chemotherapy Response

Poor chemotherapy response is the main obstacle of ovarian cancer (OC) treatment. Platinum‐refractory and ‐resistant patients are associated with a worse outcome than platinum‐sensitive and partially sensitive patients, but the comprehensive similarities and differences among them are not yet clear. In this study, we analyzed the data of patients with different chemotherapy response in The Cancer Genome Atlas. We found a minority of altered genes were overlapped in refractory and resistant groups, as did the enriched pathways and Gene Ontology terms. We noticed that the neural signaling and drug metabolism enzymes were more significantly enriched and the protein–protein interaction supported these results. The transcription analysis highlighted PDX1 as the common and central transcription factor in both refractory and resistant groups. The competing endogenous RNA (ceRNA) network shared no common ceRNA pairs, indicating a major difference in noncoding RNA post‐transcriptional regulation. In the end, we validated the expression, regulation, binding, and effect on chemotherapy response for selected MNX1‐AS1/hsa‐miR‐4697‐3p/HOXB13 in OC cell lines. Our study offered a novel and comprehensive insight into chemotherapy response, and potential targets for improving chemotherapy response in OC.

An open-label phase I dose-escalation study of the safety and pharmacokinetics of DMUC4064A in patients with platinum-resistant ovarian cancer

OBJECTIVES

MUC16 is overexpressed in the majority of human epithelial ovarian cancers (OC). DMUC4064A is a humanized anti-MUC16 monoclonal antibody conjugated to the microtubule-disrupting agent monomethyl auristatin E. This trial assessed the safety, tolerability, pharmacokinetics, and preliminary activity of DMUC4064A in patients with platinum-resistant OC.

METHODS

DMUC4064A was administered once every 3 weeks to patients in 1.0-5.6 mg/kg dose escalation cohorts, followed by cohort expansion at the recommended Phase II dose (RP2D).

RESULTS

Sixty-five patients were enrolled and received a median of 5 cycles (range 1-20) of DMUC4064A. The maximum tolerated dose was not reached; 5.2 mg/kg was the RP2D based on the overall tolerability profile. The most common adverse events were fatigue, nausea, abdominal pain, constipation, blurred vision, diarrhea, and anemia. Sixteen patients (25%) experienced related grade ≥ 3 toxicities. Twenty-six patients (40%) experienced ocular toxicities. The exposure of acMMAE was dose proportional, with a half-life of ~6 days. Sixteen patients (25%) experienced confirmed objective partial response (PR or CR) starting at ≥3.2 mg/kg dose levels, while 23 (35%) patients had best responses of PR or CR. Overall, the clinical benefit rate was 42% (27 patients with a best response [confirmed and unconfirmed] of CR, or PR or SD lasting ≥6 months). Among the 54 patients with high MUC16 immunohistochemistry scores, the clinical benefit rate was 46% (25 patients). Median progression-free survival was 3.9 months overall.

CONCLUSIONS

In this Phase I study, DMUC4064A demonstrated a tolerable safety profile along with encouraging efficacy in the indication of platinum-resistant OC.

Apatinib treatment efficiently delays biochemical-only recurrent ovarian cancer progression

Background

Biochemical recurrence is defined as only rising CA-125 but no radiographic evidence of disease; noteworthily, it generally precedes the onset of clinical evidence. Now treatment strategies of biochemical recurrence ovarian cancer (OC) remain controversial. Apatinib as monotherapy or in combination with other chemotherapeutic agents has shown its effect in the treatment of some advanced malignancies. In our study, we focused on the efficacy of apatinib in recurrent OC, especially its clinical activity in biochemical-only recurrent OC patients.

Methods

We retrospectively analyzed clinical material of 41 recurrent patients who had received apatinib monotherapy or apatinib plus chemotherapy between June 2016 and August 2018. Apatinib was administered at a 500mg daily dose. Response was determined according to measurable disease or serum carbohydrate antigen (CA)-125 levels. Progression-free survival (PFS) was estimated by Kaplan–Meier method.

Results

All patients were evaluable, 19 (46.34%) had biochemical relapse and 22 (53.66%) had clinical relapse. The objective response rate (ORR) and disease control rate (DCR) in the overall population were 31.71% and 78.05%, respectively. The median PFS was 7 months (95% confidence interval 5.43–8.57). And in patients with biochemical-only relapse, the median PFS was 6 months, with ORR of 26.32% and DCR of 89.47%.

Conclusions

Apatinib is a well-tolerated and effective agent to delay clinical progression of patients with biochemical-only recurrent OC. More important, our study shows the promising prospect for treating OC patients with asymptomatic biochemical relapse.

A polygenic methylation prediction model associated with response to chemotherapy in epithelial ovarian cancer

To identify potential aberrantly differentially methylated genes (DMGs) correlated with chemotherapy response (CR) and establish a polygenic methylation prediction model of CR in epithelial ovarian cancer (EOC), we accessed 177 (47 chemo-sensitive and 130 chemo-resistant) samples corresponding to three DNA-methylation microarray datasets from the Gene Expression Omnibus and 306 (290 chemo-sensitive and 16 chemo-resistant) samples from The Cancer Genome Atlas (TCGA) database. DMGs associated with chemotherapy sensitivity and chemotherapy resistance were identified by several packages of R software. Pathway enrichment and protein-protein interaction (PPI) network analyses were constructed by Metascape software. The key genes containing mRNA expressions associated with methylation levels were validated from the expression dataset by the GEO2R platform. The determination of the prognostic significance of key genes was performed by the Kaplan-Meier plotter database. The key genes-based polygenic methylation prediction model was established by binary logistic regression. Among accessed 483 samples, 457 (182 hypermethylated and 275 hypomethylated) DMGs correlated with chemo resistance. Twenty-nine hub genes were identified and further validated. Three genes, anterior gradient 2 (AGR2), heat shock-related 70-kDa protein 2 (HSPA2), and acetyltransferase 2 (ACAT2), showed a significantly negative correlation between their methylation levels and mRNA expressions, which also corresponded to prognostic significance. A polygenic methylation prediction model (0.5253 cutoff value) was established and validated with 0.659 sensitivity and 0.911 specificity.

Differential DNA methylation in high-grade serous ovarian cancer (HGSOC) is associated with tumor behavior

The epigenome offers an additional facet of cancer that can help categorize patients into those at risk of disease, recurrence, or treatment failure. We conducted a retrospective, nested, case-control study of advanced and recurrent high-grade serous ovarian cancer (HGSOC) patients in which we assessed epigenome-wide association using Illumina methylationEPIC arrays to characterize DNA methylation status and RNAseq to evaluate gene expression. Comparing HGSOC tumors with normal fallopian tube tissues we observe global hypomethylation but with skewing towards hypermethylation when interrogating gene promoters. In total, 5,852 gene interrogating probes revealed significantly different methylation. Within HGSOC, 57 probes highlighting 17 genes displayed significant differential DNA methylation between primary and recurrent disease. Between optimal vs suboptimal surgical outcomes 99 probes displayed significantly different methylation but only 29 genes showed an inverse correlation between methylation status and gene expression. Overall, differentially methylated genes point to several pathways including RAS as well as hippo signaling in normal vs primary HGSOC; valine, leucine, and isoleucine degradation and endocytosis in primary vs recurrent HGSOC; and pathways containing immune driver genes in optimal vs suboptimal surgical outcomes. Thus, differential DNA methylation identified numerous genes that could serve as potential biomarkers and/or therapeutic targets in HGSOC.

Withaferin A ameliorates ovarian cancer-induced cachexia and proinflammatory signaling

BACKGROUND

Ovarian cancer is the fifth leading cause of cancer-related deaths amongst women in the United States. Cachexia is the primary cause of death in approximately 30% of cancer patients, and is often evidenced in ovarian cancer patients. We tested the steroidal lactone Withaferin A to examine if it could ameliorate ovarian cancer-induced cachexia.

METHODS

Six-week-old severely immunodeficient female mice were xenografted with the ovarian cancer cell line A2780 followed by treatment with Withaferin A or vehicle. Changes in functional grip strength were assessed on a weekly basis. Postmortem, H&E staining was performed on skeletal muscle sections and immunofluorescent immunohistochemistry was performed on skeletal muscle and tumor sections. The levels of NF-κB-related proinflammatory cytokines were assessed in the xenografted tumors and in resident host skeletal muscle.

RESULTS

Xenografting of the A2780 cell line resulted in a significant rate of mortality, which was attenuated by a therapeutic dosage of Withaferin A. Mice that received vehicle treatment following xenografting exhibited functional muscle decline over the course of the study. The therapeutic dosage Withaferin A treatment attenuated this reduction in grip strength, whereas the supratherapeutic dosage of Withaferin A was found to be toxic/lethal and demonstrated a further decline in functional muscle strength and an increased rate of mortality on par with vehicle treatment. At a histological level, the vehicle treated tumor-bearing mice exhibited a profound reduction in myofibrillar cross-sectional area compared to the vehicle treated tumor-free control group. The atrophic changes induced by the xenografted tumor were significantly ameliorated by treatment with Withaferin A. The combination of functional muscle weakening and induction of myofibrillar atrophy corroborate a cachectic phenotype, which was functionally rescued by Withaferin A. Further, treatment completely abolished the slow-to-fast myofiber type conversion observed in the settings of cancer-induced cachexia. In both host resident skeletal muscle and the xenografted tumors, we report an increase in NF-κB-related proinflammatory cytokines that was reversed by Withaferin A treatment. Finally, we demonstrated that Withaferin A significantly downregulates cytosolic and nuclear levels of phospho-p65, the active canonical NF-κB transcription factor, in xenografted tumors.

CONCLUSIONS

Cumulatively, our results demonstrate a previously overlooked role of Withaferin A in a xenograft model of ovarian cancer. We propose mechanisms by which Withaferin A reduces NF-κB-dependent pro-inflammatory cytokine production leading to an attenuation of the cachectic phenotype in an i.p. xenograft model of ovarian cancer.

Ovarian Cancer Stemness: Biological and Clinical Implications for Metastasis and Chemotherapy Resistance

Epithelial ovarian cancer is a highly lethal gynecological malignancy that is characterized by the early development of disseminated metastasis. Though ovarian cancer has been generally considered to preferentially metastasize via direct transcoelomic dissemination instead of the hematogenous route, emerging evidence has indicated that the hematogenous spread of cancer cells plays a larger role in ovarian cancer metastasis than previously thought. Considering the distinctive biology of ovarian cancer, an in-depth understanding of the biological and molecular mechanisms that drive metastasis is critical for developing effective therapeutic strategies against this fatal disease. The recent “cancer stem cell theory” postulates that cancer stem cells are principally responsible for tumor initiation, metastasis, and chemotherapy resistance. Even though the hallmarks of ovarian cancer stem cells have not yet been completely elucidated, metastasized ovarian cancer cells, which have a high degree of chemoresistance, seem to manifest cancer stem cell properties and play a key role during relapse at metastatic sites. Herein, we review our current understanding of the cell-biological mechanisms that regulate ovarian cancer metastasis and chemotherapy resistance, with a pivotal focus on ovarian cancer stem cells, and discuss the potential clinical implications of evolving cancer stem cell research and resultant novel therapeutic approaches.

Comparative efficacy of targeted maintenance therapy for newly diagnosed epithelial ovarian cancer: a network meta-analysis

Background: The number of published randomized clinical trials (RCTs) using targeted maintenance therapy for newly diagnosed epithelial ovarian cancer is increasing. Our objective was to evaluate the comparative effectiveness of each maintenance therapy using a network meta-analysis.

Materials and methods: A systematic search for RCTs was conducted using Medline, Embase, and CENTRAL databases followed by a Bayesian network meta-analysis. The primary outcome was progression-free survival (PFS) and the secondary outcome was overall survival (OS). Pooled hazard ratios (HRs) with 95% credible intervals (95% CrIs) were used to estimate outcomes.

Results: A total of 11 RCTs involving 6631 patients were included. Network meta-analysis showed that pure maintenance therapy with pazopanib resulted in a significantly better PFS compared with placebo (HR, 0.77; 95% CrI, 0.65–0.92). Bevacizumab-throughout treatment was also associated with a better PFS (HR, 0.76, 95% CrI, 0.69–0.84). However, anti-CA-125 monoclonal antibodies (abagovomab and oregovomab) showed no significant survival benefit. Moreover, combined analysis showed that targeted-throughout was not significantly superior to pure targeted maintenance therapy for PFS and OS. Stratified analysis showed paralleled results with no significant difference between pazopanib pure maintenance and bevacizumab-throughout treatments.

Conclusion: Our study showed a survival advantage conferred by pazopanib and bevacizumab as maintenance therapy in newly diagnosed epithelial ovarian cancer. Further clinical trials are essential to both determine the effect of bevacizumab in the maintenance stage and identify the specific subgroup(s) that benefit.

CD44 Regulates Formation of Spheroids and Controls Organ-Specific Metastatic Colonization in Epithelial Ovarian Carcinoma

Disseminating epithelial ovarian cancer cells often become assembled into spheroids prior to their arrival at metastatic sites within the peritoneal cavity. Although epithelial ovarian carcinoma (EOC) is the deadliest gynecologic malignancy, the mechanisms regulating formation and metastatic potential of spheroids are poorly understood. We show that expression of a cell surface glycoprotein CD44 is an important contributing factor for spheroid formation and spheroid adhesion to mesothelial cells, and its loss impairs mesenteric metastasis. In contrast, loss of CD44 resulted in significant increase of tumor burden at several locoregional sites, including liver, and unleashed distant metastases to the thoracic cavity. Altogether our studies suggest that CD44 regulates metastatic progression of EOC in an organ-specific manner. IMPLICATIONS: Expression of CD44 promotes spheroid formation, mesothelial adhesion, and formation of mesenteric metastasis, but it suppresses development of metastasis to several peritoneal sites, including liver, and the thoracic cavity.

Phase I/Ib study of olaparib and carboplatin in heavily pretreated recurrent high-grade serous ovarian cancer at low genetic risk

Purpose: To investigate maximum tolerated dose (MTD), activity and predictive biomarkers of olaparib with carboplatin in BRCA wild-type (BRCAwt) high grade serous ovarian carcinoma (HGSOC) patients. Methods: A 3+3 dose escalation study examined olaparib capsules (400 mg twice daily [BID], days 1-7) with carboplatin (AUC3-5 on day 1) every 21 days for 8 cycles, followed by olaparib 400 mg BID maintenance. Blood and tumor biopsy samples were collected pre- and on-treatment in the expansion cohort for PAR levels and proteomic endpoints. Results: 30 patients (median 7 prior regimens [2-12], 63% (19/30) platinum-resistant) were enrolled. Dose-limiting toxicity was thrombocytopenia/neutropenia, and infection with carboplatin AUC5 (2/6 patients). MTD was olaparib 400 mg BID + carboplatin AUC4. Grade 3/4 adverse events (>10%) included neutropenia (23%), thrombocytopenia (20%), and anemia (13%). Five of 25 (20%) evaluable patients had partial response (PR; median 4.5 months [3.3-9.5]). Clinical benefit rate (PR + stable disease ≥4 months) was 64% (16/25). A greater decrease in tissue PAR levels was seen in the clinical benefit group versus no benefit (median normalized linear change -1.84 [-3.39- -0.28] vs 0.51 [-0.27- 1.29], p = 0.001) and a DNA repair score by proteomics did not correlate with response. Conclusions: The olaparib and carboplatin combination is tolerable and has clinical benefit in subsets of heavily pretreated BRCAwt HGSOC, independent of platinum sensitivity.

TRRAP stimulates the tumorigenic potential of ovarian cancer stem cells

Ovarian cancer is the most fatal gynecological malignancy in women and identification of new therapeutic targets is essential for the continued development of therapy for ovarian cancer. TRRAP (transformation/transcription domain-associated protein) is an adaptor protein and a component of histone acetyltransferase complex. The present study was undertaken to investigate the roles played by TRRAP in the proliferation and tumorigenicity of ovarian cancer stem cells. TRRAP expression was found to be up-regulated in the sphere cultures of A2780 ovarian cancer cells. Knockdown of TRRAP significantly decreased cell proliferation and the number of A2780 spheroids. In addition, TRRAP knockdown induced cell cycle arrest and increased apoptotic percentages of A2780 sphere cells. Notably, the mRNA levels of stemness-associated markers, that is, OCT4, SOX2, and NANOG, were suppressed in TRRAP-silenced A2780 sphere cells. In addition, TRRAP overexpression increased the mRNA level of NANOG and the transcriptional activity of NANOG promoter in these cells. Furthermore, TRRAP knockdown significantly reduced tumor growth in a murine xenograft transplantation model. Taken together, the findings of the present study suggest that TRRAP plays an important role in the regulation of the proliferation and stemness of ovarian cancer stem cells.

Methylation and ovarian cancer: Can DNA methylation be of diagnostic use?

Ovarian cancer is a silent killer and, due to late diagnosis and frequent chemo resistance in patients, the primary cause of fatality amongst the various types of gynecological cancer. The discovery of a specific and sensitive biomarker for ovarian cancer could improve early diagnosis, thereby saving lives. Biomarkers could also improve treatment, by predicting which patients will benefit from specific treatment strategies. DNA methylation is an epigenetic mechanism, and 'methylation imbalance' is characteristic of cancer. Previous research suggests that changes in DNA methylation can be used diagnostically, and that they may predict resistance to treatment. This paper gives an up-to-date overview of research investigating the potential of DNA methylation-based markers for diagnostics, prognostics, screening and prediction of drug resistance for ovarian cancer patients. DNA methylation cancer-biomarkers may be useful for cancer treatment, particularly since they are chemically stable and since cancer-associated changes in methylation typically precedes tumor growth. DNA methylation markers could improve diagnosis and treatment and might even be used for screening in the future. Furthermore, DNA methylation biomarkers could facilitate the development of precision medicine. However, at this point no biomarkers for ovarian cancer have a sufficient combination of sensitivity and specificity in a clinical setting. A reason for this is that most studies have focused on a single or a few methylation sites. More large screenings and genome-wide studies must be performed to increase the chance of identifying a DNA methylation marker which can identify ovarian cancer.

Extracellular vesicle-associated miRNAs in ovarian cancer – design of an integrated NGS-based workflow for the identification of blood-based biomarkers for platinum-resistance

Background

Extracellular vesicle (EV)-associated microRNAs (miRNAs) have been suggested as promising biomarkers for blood-based cancer diagnosis. However, one of the major limitations for the use of EVs with diagnostic purpose is the lack of standardized EV-profiling techniques. In this regard, the objective of our study was to design an integrated next-generation sequencing (NGS)-based workflow for analyzing the signature of EV-associated miRNA in the plasma of platinum-resistant ovarian cancer patients.

Methods

For EV-extraction, different enrichment methods were compared (ExoQuick vs. exoRNeasy). NGS was performed with the Illumina platform.

Results

We established an integrated NGS-based workflow, including EV-enrichment with the ExoQuick system, which resulted in an optimal RNA-yield and consistent small RNA libraries. We applied this workflow in a pilot cohort of clinically documented platinum-sensitive (n=15) vs. platinum-resistant (n=15) ovarian cancer patients, resulting in a panel of mature EV-associated miRNAs (including ovarian cancer associated miR-181a, miR-1908, miR-21, miR-486 and miR-223), which were differentially abundant in the plasma of platinum-resistant patients.

Conclusions

This is the first study, analyzing the profile of EV-associated miRNAs in platinum-resistant ovarian cancer patients. We provide rationale to further validate these miRNA candidates in an independent set of patients, in order to characterize their biomarker potential as predictors for platinum-resistance.

EMT-like circulating tumor cells in ovarian cancer patients are enriched by platinum-based chemotherapy

Background

Assuming that tumor cell dissemination requires a shift to a mesenchymal phenotype, we analyzed the incidence of epithelial-to-mesenchymal-transition (EMT)-like circulating tumor cells (CTCs) in ovarian cancer patients and inquired, how their molecular phenotypes respond to platinum-based chemotherapy and influence outcome.

Results

Before surgery, overall detection rate for epithelial CTCs was 18%. EMT-like CTCs were more frequently observed (30%) and were mutually exclusive to epithelial CTCs in the majority of patients (82%). After chemotherapy, EMT-like CTCs increased up to 52%, accompanied by the “de novo” emergence of PI3Kα+/Twist+ EMT-like CTCs. Before surgery, PI3K+ EMT-like CTCs in combination with epithelial CTCs indicated decreased OS (p = 0.02) and FIGO I-III patients with residual tumor burden after surgery were more likely to be positive for EMT-like CTCs after chemotherapy (p = 0.02). In the latter group, epithelial CTCs alone significantly correlated with decreased PFS and OS (p = 0.02, p = 0.002), supported by an additional inclusion of PI3K+ CTCs (OS, p = 0.001).

Materials and Methods

Blood samples of 91 ovarian cancer patients before surgery and 31 matched samples after adjuvant chemotherapy were evaluated for CTCs with the AdnaTest ovarian cancer and EMT-1, analyzing the epithelial-associated transcripts EpCAM, Muc-1 and CA125 and the EMT-associated transcripts PI3Kα, Akt-2 and Twist.

Conclusions

Platinum-based chemotherapy seems to select for EMT-like CTCs in ovarian cancer patients and provokes a shift towards PI3Kα and Twist expressing CTCs, which may reflect clonal tumor evolution towards therapy resistance. It has to be determined, whether this CTC subgroup may serve as a biomarker to identify patients at high risk.

Cost-effectiveness of different strategies to prevent breast and ovarian cancer in German women with a BRCA 1 or 2 mutation

BACKGROUND

Women with a BRCA1 or BRCA2 mutation are at increased risk of developing breast and/or ovarian cancer. This economic modeling study evaluated different preventive interventions for 30-year-old women with a confirmed BRCA (1 or 2) mutation.

METHODS

A Markov model was developed to estimate the costs and benefits [i.e., quality-adjusted life years (QALYs), and life years gained (LYG)] associated with prophylactic bilateral mastectomy (BM), prophylactic bilateral salpingo-oophorectomy (BSO), BM plus BSO, BM plus BSO at age 40, and intensified surveillance. Relevant input data was obtained from a large German database including 5902 women with BRCA 1 or 2, and from the literature. The analysis was performed from the German Statutory Health Insurance (SHI) perspective. In order to assess the robustness of the results, deterministic and probabilistic sensitivity analyses were performed.

RESULTS

With costs of €29,434 and a gain in QALYs of 17.7 (LYG 19.9), BM plus BSO at age 30 was less expensive and more effective than the other strategies, followed by BM plus BSO at age 40. Women who were offered the surveillance strategy had the highest costs at the lowest gain in QALYs/LYS. In the probabilistic sensitivity analysis, the probability of cost-saving was 57% for BM plus BSO. At a WTP of 10,000 € per QALY, the probability of the intervention being cost-effective was 80%.

CONCLUSIONS

From the SHI perspective, undergoing BM plus immediate BSO should be recommended to BRCA 1 or 2 mutation carriers due to its favorable comparative cost-effectiveness.

ERCC1-expressing circulating tumor cells as a potential diagnostic tool for monitoring response to platinum-based chemotherapy and for predicting post-therapeutic outcome of ovarian cancer

Background

We recently showed that the presence of ERCC1⁺CTCs is an independent predictive biomarker for platinum-resistance and poor prognosis of ovarian cancer. The goal of our current research was to determine how the auxiliary assessment of ERCC1-transcripts influences overall CTC-detection rate. We extended this investigation from an initially predictive setting to paired pre- and post-therapeutic blood analysis in order to see, whether ERCC1⁺CTCs dynamics mirror response to chemotherapy.

Methods

65 Paired blood samples (10ml) of primary ovarian cancer patients at primary diagnosis and after chemotherapy were studied for CTCs with the AdnaTest Ovarian Cancer (QIAGEN Hannover GmbH). We analyzed the tumor-associated transcripts EpCAM, MUC-1 and CA-125. ERCC1-transcripts were investigated in a separate approach by singleplex RT-PCR.

RESULTS

Auxiliary assessment of ERCC1-transcripts enhanced the overall CTC-detection rate up to 17%. ERCC1⁺CTCs (defined as positive for one of the AdnaTest markers plus ERCC1-positivity) were detected in 15% of patients at primary diagnosis and in 12% after chemotherapy. The presence of ERCC1⁺CTCs after chemotherapy correlated with platinum-resistance (P=0.01), reduced PFS (P=0.0293) and OS (P=0.0008) and their persistence indicated poor post-therapeutic outcome (PFS: P=0.005; OS: P=0.0058). Interestingly, the assessment of ERCC1-transcripts alone was sufficient for the detection of prognostic relevant ERCC1-expressing CTCs.

Conclusion

Auxiliary assessment of ERCC1-transcripts expands the phenotypic spectrum of CTC detection and defines an additional overlapping fraction of ERCC1-expressing CTCs, which are potentially selected by platinum-based chemotherapy. Specifically, we suggest that ERCC1⁺CTCs could additionally be useful as a surrogate for monitoring platinum-based chemotherapy and to assess the post-therapeutic outcome of ovarian cancer.

Association of the AA genotype of the BCL2 (–938C>A) promoter polymorphism with better survival in ovarian cancer

Background

Bcl-2 plays a key role in the regulation of apoptosis. Recently, a novel regulatory single nucleotide polymorphism (–938C>A) in the inhibitory P2 BCL2 promoter was described. In this study we investigated its potential association with survival in epithelial ovarian cancer.

Experimental design

Patients (n=110) with primary epithelial ovarian cancer were retrospectively genotyped by pyrosequencing.

Results

Genotype distribution was not significantly different between 110 ovarian cancer patients and 120 healthy controls, suggesting that genotypes of this polymorphism do not increase the susceptibility to ovarian cancer. Kaplan-Meier curves showed a significant association of the AA genotype with increased survival (p=0.002). Multivariate analysis revealed that the BCL2–938AC/CC genotype (hazard ratio 4.5; p=0.003) was an independent prognostic factor compared to other prognostic factors such as age, histological grade or tumor stage.

Conclusion

The results suggest a role for the BCL2-938C>A polymorphism as a marker for survival in patients with epithelial ovarian cancer.

Searching for new biomarkers in ovarian cancer patients: Rationale and design of a retrospective study under the Mermaid III project

Ovarian cancer is a silent killer and, due to late diagnosis, the primary cause of death amongst gynecological cancers, killing approximately 376 women annually in Denmark. The discovery of a specific and sensitive biomarker for ovarian cancer could improve early diagnosis, but also treatment, by predicting which patients will benefit from specific treatment strategies. The Mermaid III project is consisting of 3 parts including "Early detection, screening and long-term survival," "Biomarkers and/or prognostic markers" and "The infection theory." The present paper gives an overview of the part regarding biomarkers and/or prognostic markers, with a focus on rationale and design. The study described has 3 major branches: microRNAs, epigenetics and Next Generation Sequencing. Tissue and blood from ovarian cancer patients, already enrolled in the prospective ongoing pelvic mass cohort, will be examined. Relevant microRNAs and DNA methylation patterns will be investigated using array technology. Patient exomes will be fully sequenced, and identified genetic variations will be validated with Next Generation Sequencing. In all cases, data will be correlated with clinical information on the patient, in order to identify possible biomarkers. A thorough investigation of biomarkers in ovarian cancer, including large numbers of different markers, has never been done before. Besides from improving diagnosis and treatment, other outcomes could be markers for screening, knowledge of the molecular aspects of cancer and the discovery of new drugs. Moreover, biomarkers are a prerequisite for the development of precision medicine. This study will attack the ovarian cancer problem from several angles, thereby increasing the chance of successfully contributing to saving lives.

CKAP2 Promotes Ovarian Cancer Proliferation and Tumorigenesis Through the FAK-ERK Pathway

Upregulation of cytoskeleton-associated protein 2 (CKAP2) has been observed in ovarian cancer. This study aimed to determine the effects of overexpression of CKAP2 on cell proliferation and tumorigenesis and to explore the potential signal pathway in the oncogenic process. Expression of CKAP2 in tissue of ovarian cancer patients was detected. Human cancer cell line SKOV3 was overexpressed with CKAP2 and measured for cell growth and mobility. Moreover, CKAP2 effect was estimated using mouse tumor xenografts. mRNA expression levels of related genes were assessed. Expression levels of CKAP2 and p-ERK2 in SKOV3 cells were detected before and after treatment of focal adhesion kinase (FAK) inhibitor. mRNA and protein levels of CKAP2 were significantly elevated in human ovarian tumor tissues. Overexpression of CKAP2 in SKOV3 cells promoted cell proliferation and migration. Implantation of overexpressed SKOV3 cells showed significant tumorigenesis ability. mRNA expression levels of proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), and SNAI1 were elevated in overexpressed SKOV3 cells. Cells with CKAP2 overexpression also had significantly increased p-ERK2 level. Moreover, FAK inhibitor treatment significantly decreased CKAP2 expression levels as well as the phosphorylation level of ERK2 in SKOV3 cells. This study suggests that overexpression of CKAP2 enhanced proliferation and mobility of carcinoma cells through the FAK-ERK2 signaling pathway.

The conjugated antimetabolite 5-FdU-ECyd and its cellular and molecular effects on platinum-sensitive vs. -resistant ovarian cancer cells in vitro

Background

Resistance to platinum-based chemotherapy is a clinical challenge in the treatment of ovarian cancer (OC) and limits survival. Therefore, innovative drugs against platinum-resistance are urgently needed. Our therapeutic concept is based on the conjugation of two chemotherapeutic compounds to a monotherapeutic pro-drug, which is taken up by cancer cells and cleaved into active cytostatic metabolites. We explore the activity of the duplex-prodrug 5-FdU-ECyd, covalently linking 2'-deoxy-5-fluorouridine (5-FdU) and 3'-C-ethynylcytidine (ECyd), on platinum-resistant OC cells.

Methods

In vitro assays and RNA-Sequencing were applied for characterization of 5-FdU-ECyd treated platinum-sensitive A2780 and isogenic platinum-resistant A2780cis and independent platinum-resistant Skov-3-IP OC cells.

Results

Nano molar 5-FdU-ECyd concentrations induced a rapid dose-dependent decline of cell viability in platinum-sensitive and -resistant OC cells. The effect of 5-FdU-ECyd was accompanied by the formation of DNA double strand breaks and apoptosis induction, indicated by a strong increase of pro-apoptotic molecular markers. Moreover, 5-FdU-ECyd efficiently decreased migration of platinum-resistant OC cells and inhibited clonogenic or spheroidal growth. Transcriptome analysis showed early up-regulation of CDKN1A and c-Fos in both, platinum-resistant and -sensitive cells after 5-FdU-ECyd treatment and de-regulation of distinct cellular pathways involved in cell cycle regulation, apoptosis, DNA-damage response and RNA-metabolism. Combined treatment of 5-FdU-ECyd and cisplatin did not show a synergistic cellular response, suggesting the potential use of 5-FdU-ECyd as a monotherapeutic agent.

Conclusion

Our data provide novel mechanistic insight into the anti-tumor effect of 5-FdU-ECyd and we hypothesize that this duplex-prodrug could be a promising therapeutic option for OC patients with resistance to platinum-based chemotherapy.

Withaferin A (WFA) inhibits tumor growth and metastasis by targeting ovarian cancer stem cells

Ovarian cancer is the fifth leading cause of deaths due to cancer among women in the United States. In 2017, 22,440 women are expected to be diagnosed with ovarian cancer and 14,080 women will die with it. Currently used chemotherapies (Cisplatin or platinum/taxane combination) targets cancer cells, but spares cancer stem cells (CSCs), which are responsible for tumor relapse leading to recurrence of cancer. Aldehyde dehydrogenase I (ALDH1) positive cancer stem cells are one of the major populations in ovarian tumor and have been related to tumor progression and metastasis. In our studies, we observed expression of ALDH1 in both ovarian surface epithelium (OSE) and cortex with high levels of expression in OSE in normal ovary and benign (BN) tumor, compared to borderline (BL) and high grade (HG) ovarian tumors. In contrast, high levels of expression of ALDH1 were observed in cortex in BL and HG tumors compared to normal ovary and BN tumor. Withaferin A (WFA) alone or in combination with cisplatin (CIS) significantly inhibited the spheroid formation (tumorigenic potential) of isolated ALDH1 CSCs in vitro and significantly reduced its expression in tumors collected from mice bearing orthotopic ovarian tumor compared to control. Treatment of animals with CIS alone significantly increased the ALDH1 CSC population in tumors, suggesting that CIS targets cancer cells but spares cancer stem cells, which undergo amplification. WFA and CIS combination suppresses the expression of securin an “oncogene”, suggesting that securin may serve as a downstream signaling gene to mediate the antitumor effects of WFA.

ERCC1-expressing circulating tumor cells as a potential diagnostic tool for monitoring response to platinum-based chemotherapy and for predicting post-therapeutic outcome of ovarian cancer

BACKGROUND

We recently showed that the presence of ERCC1+CTCs is an independent predictive biomarker for platinum-resistance and poor prognosis of ovarian cancer. The goal of our current research was to determine how the auxiliary assessment of ERCC1-transcripts influences overall CTC-detection rate. We extended this investigation from an initially predictive setting to paired pre- and post-therapeutic blood analysis in order to see, whether ERCC1+CTCs dynamics mirror response to chemotherapy.

METHODS

65 Paired blood samples (10ml) of primary ovarian cancer patients at primary diagnosis and after chemotherapy were studied for CTCs with the AdnaTest Ovarian Cancer (QIAGEN Hannover GmbH). We analyzed the tumor-associated transcripts EpCAM, MUC-1 and CA-125. ERCC1-transcripts were investigated in a separate approach by singleplex RT-PCR.

RESULTS

Auxiliary assessment of ERCC1-transcripts enhanced the overall CTC-detection rate up to 17%. ERCC1+CTCs (defined as positive for one of the AdnaTest markers plus ERCC1-positivity) were detected in 15% of patients at primary diagnosis and in 12% after chemotherapy. The presence of ERCC1+CTCs after chemotherapy correlated with platinum-resistance (P=0.01), reduced PFS (P=0.0293) and OS (P=0.0008) and their persistence indicated poor post-therapeutic outcome (PFS: P=0.005; OS: P=0.0058). Interestingly, the assessment of ERCC1-transcripts alone was sufficient for the detection of prognostic relevant ERCC1-expressing CTCs.

CONCLUSION

Auxiliary assessment of ERCC1-transcripts expands the phenotypic spectrum of CTC detection and defines an additional overlapping fraction of ERCC1-expressing CTCs, which are potentially selected by platinum-based chemotherapy. Specifically, we suggest that ERCC1+CTCs could additionally be useful as a surrogate for monitoring platinum-based chemotherapy and to assess the post-therapeutic outcome of ovarian cancer.

ERCC1-expressing circulating tumor cells as a potential diagnostic tool for monitoring response to platinum-based chemotherapy and for predicting post-therapeutic outcome of ovarian cancer

BACKGROUND

We recently showed that the presence of ERCC1+CTCs is an independent predictive biomarker for platinum-resistance and poor prognosis of ovarian cancer. The goal of our current research was to determine how the auxiliary assessment of ERCC1-transcripts influences overall CTC-detection rate. We extended this investigation from an initially predictive setting to paired pre- and post-therapeutic blood analysis in order to see, whether ERCC1+CTCs dynamics mirror response to chemotherapy.

METHODS

65 Paired blood samples (10ml) of primary ovarian cancer patients at primary diagnosis and after chemotherapy were studied for CTCs with the AdnaTest Ovarian Cancer (QIAGEN Hannover GmbH). We analyzed the tumor-associated transcripts EpCAM, MUC-1 and CA-125. ERCC1-transcripts were investigated in a separate approach by singleplex RT-PCR.

RESULTS

Auxiliary assessment of ERCC1-transcripts enhanced the overall CTC-detection rate up to 17%. ERCC1+CTCs (defined as positive for one of the AdnaTest markers plus ERCC1-positivity) were detected in 15% of patients at primary diagnosis and in 12% after chemotherapy. The presence of ERCC1+CTCs after chemotherapy correlated with platinum-resistance (P=0.01), reduced PFS (P=0.0293) and OS (P=0.0008) and their persistence indicated poor post-therapeutic outcome (PFS: P=0.005; OS: P=0.0058). Interestingly, the assessment of ERCC1-transcripts alone was sufficient for the detection of prognostic relevant ERCC1-expressing CTCs.

CONCLUSION

Auxiliary assessment of ERCC1-transcripts expands the phenotypic spectrum of CTC detection and defines an additional overlapping fraction of ERCC1-expressing CTCs, which are potentially selected by platinum-based chemotherapy. Specifically, we suggest that ERCC1+CTCs could additionally be useful as a surrogate for monitoring platinum-based chemotherapy and to assess the post-therapeutic outcome of ovarian cancer.

Clinical validation of chemotherapy predictors developed on global microRNA expression in the NCI60 cell line panel tested in ovarian cancer

OBJECTIVE

Ovarian cancer is the leading cause of death among gynecologic malignancies. This is partly due to a non-durable response to chemotherapy. Prediction of resistance to chemotherapy could be a key role in more personalized treatment. In the current study we aimed to examine if microRNA based predictors could predict resistance to chemotherapy in ovarian cancer, and to investigate if the predictors could be prognostic factors for progression free and overall survival.

METHODS

Predictors of chemotherapy-resistance were developed based on correlation between miRNA expression and differences in measured growth inhibition in a variety of human cancer cell lines in the presence of Carboplatin, Paclitaxel and Docetaxel. These predictors were then, retrospectively, blindly validated in a cohort of 170 epithelial ovarian cancer patients treated with Carboplatin and Paclitaxel or Docetaxel as first line treatment.

RESULTS

In a multivariate cox proportional analysis the predictors of chemotherapy-resistance were not able to predict time to progression after end of chemotherapy (hazard ratio: 0.64, 95% CI: 0.36-1.12, P = 0.117). However, in a multivariate logistic analysis, where time to progression was considered as either more or less than 6 months, the predictors match clinical observed chemotherapy-resistance (odds ratio: 0.19, 95% CI: 0.05-0.73, P = 0.015). Neither univariate nor multivariate, time-dependent, cox analysis for progression free survival (PFS) or overall survival (OS) in all 170 patients showed to match predicted resistance to chemotherapy (PFS: hazard ratio: 0.69, 95% CI: 0.40-1.19, P = 0.183, OS: hazard ratio: 0.76, 95% CI: 0.42-1.40, P = 0.386).

CONCLUSION

In the current study, microRNA based predictors of chemotherapy-resistance did not demonstrate any convincing correlation to clinical observed chemotherapy-resistance, progression free survival, or overall survival, in patients with epithelial ovarian cancer. However the predictors did reflect relapse more or less than 6 months.

Establishment and characterization of a platinum- and paclitaxel-resistant high grade serous ovarian carcinoma cell line

High grade serous ovarian cancer (HGSOC) patients have a high recurrence rate after surgery and adjuvant chemotherapy due to inherent or acquired drug resistance. Cell lines derived from HGSOC tumors that are resistant to chemotherapeutic agents represent useful pre-clinical models for drug discovery. Here, we describe establishment of a human ovarian carcinoma cell line, which we term WHIRC01, from a patient-derived mouse xenograft established from a chemorefractory HGSOC patient who did not respond to carboplatin and paclitaxel therapy. This newly derived cell line is platinum- and paclitaxel-resistant with cisplatin, carboplatin, and paclitaxel half-maximal lethal doses of 15, 130, and 20 µM, respectively. Molecular characterization of this cell line was performed using targeted DNA exome sequencing, transcriptomics (RNA-seq), and mass spectrometry-based proteomic analyses. Results from exomic sequencing revealed mutations in TP53 consistent with HGSOC. Transcriptomic and proteomic analyses of WHIRC01 showed high level of alpha-enolase and vimentin, which are associated with cell migration and epithelial-mesenchymal transition. WHIRC01 represents a chemorefractory human HGSOC cell line model with a comprehensive molecular profile to aid future investigations of drug resistance mechanisms and screening of chemotherapeutic agents.

PKCι regulates nuclear YAP1 localization and ovarian cancer tumorigenesis

Atypical protein kinase Cι (PKCι) is an oncogene in lung and ovarian cancer. The PKCι gene PRKCI is targeted for frequent tumor-specific copy number gain (CNG) in both lung squamous cell carcinoma (LSCC) and ovarian serous carcinoma (OSC). We recently demonstrated that in LSCC cells PRKCI CNG functions to drive transformed growth and tumorigenicity by activating PKCι-dependent cell autonomous Hedgehog (Hh) signaling. Here, we assessed whether OSC cells harboring PRKCI CNG exhibit similar PKCι-dependent Hh signaling. Surprisingly, we find that whereas PKCι is required for the transformed growth of OSC cells harboring PRKCI CNG, these cells do not exhibit PKCι-dependent Hh signaling or Hh-dependent proliferation. Rather, transformed growth of OSC cells is regulated by PKCι-dependent nuclear localization of the oncogenic transcription factor, YAP1. Lentiviral shRNA-mediated knockdown (KD) of PKCι leads to decreased nuclear YAP1 and increased YAP1 binding to angiomotin (AMOT), which sequesters YAP1 in the cytoplasm. Biochemical analysis reveals that PKCι directly phosphorylates AMOT at a unique site, Thr750, whose phosphorylation inhibits YAP1 binding. Pharmacologic inhibition of PKCι decreases YAP1 nuclear localization and blocks OSC tumor growth in vitro and in vivo. Immunohistochemical analysis reveals a strong positive correlation between tumor PKCι expression and nuclear YAP1 in primary OSC tumor samples, indicating the clinical relevance of PKCι-YAP1 signaling. Our results uncover a novel PKCι-AMOT-YAP1 signaling axis that promotes OSC tumor growth, and provide a rationale for therapeutic targeting of this pathway for treatment of OSC.

Prognostic Significance of Preoperative Prognostic Nutritional Index in Epithelial Ovarian Cancer Patients Treated with Platinum-Based Chemotherapy

BACKGROUND

The aim of present study was to investigate the role of the prognostic nutritional index (PNI) used as a prognostic marker for predicting response and survival outcomes in patients with epithelial ovarian cancer (EOC) who are receiving platinum-based chemotherapy.

PATIENTS AND METHODS

Patients with a new diagnosis of EOC receiving postoperative platinum-based chemotherapy were identified. The PNI was calculated as 10 × serum albumin value (g/dl) + 0.005 × peripheral lymphocyte count (per mm3). Patients were divided into a platinum-resistant (P-R) group and a platinum-sensitive (P-S) group according to the chemotherapeutic response. A receiver operating characteristic (ROC) curve was used to calculate the optimal cut-off value for PNI to predict chemotherapeutic response and prognosis.

RESULTS

A total of 344 patients were enrolled. Area under the curve, sensitivity, and specificity of PIN < 45 to predict platinum resistance were: 0.688, 62.50%, and 83.47%, respectively. Patients with a lower PNI (< 45) had shorter progression-free survival (PFS) and overall survival (OS). PNI showed a significant association with PFS (hazard ratio (HR) 1.890, 95% confidence interval (CI) 1.396-2.560; p < 0.001) and OS (HR 1.747, 95% CI 1.293-2.360; p < 0.001).

CONCLUSION

Our results suggest that PNI assessment could assist the identification of patients with a poor prognosis and has potential clinical value in predicting platinum resistance in patients with EOC.

PKCι regulates nuclear YAP1 localization and ovarian cancer tumorigenesis

Atypical protein kinase Cι (PKCι) is an oncogene in lung and ovarian cancer. The PKCι gene PRKCI is targeted for frequent tumor-specific copy number gain (CNG) in both lung squamous cell carcinoma (LSCC) and ovarian serous carcinoma (OSC). We recently demonstrated that in LSCC cells PRKCI CNG functions to drive transformed growth and tumorigenicity by activating PKCι-dependent cell autonomous Hedgehog (Hh) signaling. Here, we assessed whether OSC cells harboring PRKCI CNG exhibit similar PKCι-dependent Hh signaling. Surprisingly, we find that whereas PKCι is required for the transformed growth for OSC cells harboring PRKCI CNG, these cells do not exhibit PKCι-dependent Hh signaling or Hh-dependent proliferation. Rather, transformed growth of OSC cells is regulated by PKCι-dependent nuclear localization of the oncogenic transcription factor, YAP1. Lentiviral shRNA-mediated knock down (KD) of PKCι leads to decreased nuclear YAP1 and increased YAP1 binding to angiomotin (AMOT), which sequesters YAP1 in the cytoplasm. Biochemical analysis reveals that PKCι directly phosphorylates AMOT at a unique site, Thr750, whose phosphorylation inhibits YAP1 binding. Pharmacologic inhibition of PKCι decreases YAP1 nuclear localization and blocks OSC tumor growth in vitro and in vivo. Immunohistochemical analysis reveals a strong positive correlation between tumor PKCι expression and nuclear YAP1 in primary OSC tumor samples, indicating the clinical relevance of PKCι-YAP1 signaling. Our results uncover a novel PKCι-AMOT-YAP1 signaling axis that promotes OSC tumor growth, and provide a rationale for therapeutic targeting of this pathway for treatment of OSC.

Gene expression profiling of single circulating tumor cells in ovarian cancer - Establishment of a multi-marker gene panel

The presence of circulating tumor cells (CTCs) in the blood of ovarian cancer patients was shown to correlate with decreased overall survival, whereby CTCs with epithelial-mesenchymal-transition (EMT) or stem-like traits are supposed to be involved in metastatic progression and recurrence. Thus, investigating the transcriptional profiles of CTCs might help to identify therapy resistant tumor cells and to overcome treatment failure. For this purpose, we established a multi-marker panel for the molecular characterization of single CTCs, detecting epithelial (EpCAM, Muc-1, CK5/7), EMT (N-cadherin, Vimentin, Snai1/2, CD117, CD146, CD49f) and stem cell (CD44, ALDH1A1, Nanog, SOX2, Notch1/4, Oct4, Lin28) associated transcripts. First primer specificity and PCR-performance of the multiplex-RT-PCRs were successfully validated on genomic DNA and cDNA isolated from OvCar3 cells. The assay sensitivity of the epithelial panel was evaluated by adding defined numbers of tumor cells into the blood of healthy donors and performing a subsequent immunomagnetic tumor cell enrichment (AdnaTest OvarianCancerSelect), resulting in a 100% concordance for the epithelial markers EpCAM and Muc-1 to the AdnaTest OvarianCancerDetect. Additionally, by processing blood from ovarian cancer patients, high assay sensitivity could be verified. In blood of healthy donors no signals for epithelial markers were detected, for EMT and stem cell markers, however, signals were obtained mainly originating from leukocytes which calls for single cell analysis. To that aim by using the ovarian cancer cell line OvCar3, we successfully established a workflow enabling the characterization of single CTCs. It consists of a density gradient-dependent enrichment for nucleated cells, a depletion of CD45-positive cells of hematopoietic origin followed by immunofluorescent labeling of CTCs by EpCAM and Muc-1. Single CTCs are then isolated by micromanipulation and processed for panel gene expression profiling. Finally, fifteen single CTCs from three ovarian cancer patients were analyzed and found to be positive for stem cell (CD44, ALDH1A1, Nanog, Oct4) and EMT markers (N-cadherin, Vimentin, Snai2, CD117, CD146). Albeit, inter-cellular and intra/inter-patient heterogeneity and co-expression of epithelial, mesenchymal and stem cell transcripts on the same CTC was observed. We have established a robust workflow to perform sensitive single cell panel gene expression analysis without the need of pre-amplification steps. Our data point towards a heterogeneous expression of stem cell and EMT associated transcripts in ovarian cancer CTCs.

Antitumor effects of cecropin B-LHRH' on drug-resistant ovarian and endometrial cancer cells

Background

Luteinizing hormone-releasing hormone receptor (LHRHr) represents a promising therapeutic target for treating sex hormone-dependent tumors. We coupled cecropin B, an antimicrobial peptide, to LHRH’, a form of LHRH modified at carboxyl-terminal residues 4–10, which binds to LHRHr without interfering with luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion. This study aimed to assess the antitumor effects of cecropin B-LHRH’ (CB-LHRH’) in drug-resistant ovarian and endometrial cancers.

Methods

To evaluate the antitumor effects of CB-LHRH’, three drug resistant ovarian cancer cell lines (SKOV-3, ES-2, NIH:OVCAR-3) and an endometrial cancer cell line (HEC-1A) were treated with CB-LHRH’. Cell morphology changes were assessed using inverted and electron microscopes. In addition, cell growth and cell cytotoxicity were measured by MTT assay and LDH release, respectively. In addition, hemolysis was measured. Furthermore, radioligand receptor binding, hypersensitization and minimal inhibitory concentrations (against Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Pseudomonas aeruginosa, and Acinetobacter baumannii) were determined. Finally, the impact on tumor growth in BALB/c-nu mice was assessed in an ES-2 xenograft model.

Results

CB-LHRH’ bound LHRHr with high-affinity (dissociation constant, Kd = 0.252 ± 0.061nM). Interestingly, CB-LHRH’ significantly inhibited the cell viability of SKOV-3, ES-2, NIH:OVCAR-3 and HEC-1A, but not that of normal eukaryotic cells. CB-LHRH’ was active against bacteria at micromolar concentrations, and caused no hypersensitivity in guinea pigs. Furthermore, CB-LHRH’ inhibited tumor growth with a 23.8 and 20.4 % reduction in tumor weight at 50 and 25 mg/kg.d, respectively.

Conclusions

CB-LHRH’ is a candidate for targeted chemotherapy against ovarian and endometrial cancers.

Establishment and Characterization of an In Vitro Model of Ovarian Cancer Stem-like Cells with an Enhanced Proliferative Capacity

The establishment of cancer stem-like cell (CSC) culture systems may be instrumental in devising strategies to fight refractory cancers. Inhibition of the Rho kinase ROCK has been shown to favorably affect CSC spheroid cultures. In this study, we show how ROCK inhibition in human serous ovarian cancer (SOC) cells can help establish a CSC system, which illuminates cancer pathophysiology and its treatment in this setting. In the presence of a ROCK kinase inhibitor, spheroid cultures of SOC cells expressed characteristic CSC markers including ALDH1A1, CD133, and SOX2, along with differentiation and tumorigenic capabilities in mouse xenograft models of human SOC. High expression levels of ALDH, but not CD133, correlated with spheroid formation CSC marker expression and tumor forming capability. In clinical specimens of SOC, high levels of ALDH1A1 correlated with advanced stage and poor prognosis. Pharmacologic or genetic blockade of ALDH blocked cell proliferation and reduced expression of SOX2, the genetic ablation of which abolished spheroid formation, whereas SOX2 overexpression inhibited ALDH1A1 expression and blocked spheroid proliferation. Taken together, our findings illustrated a new method to culture human ovarian CSC, and they defined a reciprocal regulatory relationship between ALDH1A1 and SOX2, which impacts ovarian CSC proliferation and malignant progression.

Review of the current role of targeted therapies as maintenance therapies in first and second line treatment of epithelial ovarian cancer; In the light of completed trials

Late and recurrent stage ovarian cancer has a high mortality and low response rate to therapy beyond first line treatment. Although first line platinum/taxane based regimens have a satisfactory response rate eventually in most cases disease recurrence is common and second-line treatments are not curative. Delaying progression or recurrence is the main goal of current ongoing clinical studies by means of establishing an effective maintenance regimen with acceptable toxicity profile. Clearly, the persistence of dormant and drug-resistant cells after front-line treatments results in the inability to cure the disease. Over the past several years, the idea of prolongation of therapy for ovarian cancer has garnered clinical attention and academic debate. As a result of a greater understanding of the molecular pathways involved in carcinogenesis and tumor growth, a large number of potential therapeutic targets have been identified and drugs to block receptors, ligands or pathways are being developed. Currently, numerous clinical trials with targeted agents have just been completed or are ongoing involving patients achieving a complete or durable response after first-line and beyond the first line chemotherapy in order to evaluate the efficacy of different therapeutic approaches in terms of progression-free survival and overall survival.

The FNTB promoter polymorphism rs11623866 as a potential predictive biomarker for lonafarnib treatment of ovarian cancer patients

AIM

Despite promising preclinical findings regarding clinical utility of farnesyltransferase inhibitors (FTI), such as lonafarnib, success of clinical trials is limited. A multicentre AGO-OVAR-15 phase II trial reported an unfavourable effect of lonafarnib on the outcome of patients with advanced ovarian cancer. This study was performed as a genetic subgroup analysis of the AGO-OVAR-15 trial, and investigated the utility of the promoter polymorphism rs11623866 of the farnesyltransferase ß-subunit gene (FNTB) in predicting the clinical effectiveness of lonafarnib.

METHODS

The influence of rs11623866 (c.-609G > C) on FNTB promoter activity was investigated by electrophoretic-mobility-shift assay, luciferase-reporter assay and RT-qPCR. A total of 57 out of 105 patients from the AGO-OVAR-15 trial, treated with carboplatin and paclitaxel ± lonafarnib, was genotyped for rs11623866 by restriction fragment length polymorphism analysis. Genotype-dependent survival analysis was performed by Kaplan-Meier analysis.

RESULTS

The presence of the G allele was associated with increased FNTB promoter activity compared with the C allele. An unfavourable effect of lonafarnib was limited to patients carrying a GG genotype (HRPFS 6.2, 95%CI = 2.01, 19.41, P = 0.002; HROS 9.6, 95%CI = 1.89, 48.54, P = 0.006). Median progression free survival (PFS) for patients with the GG genotype in the lonafarnib treated arm was 10 months, whereas median PFS without FTI-treatment was 40 months. Median overall survival (OS) in the lonafarnib-treated group was 19 months, whereas median OS was not reached in the untreated group.

CONCLUSIONS

Discrepancies between preclinical success and clinical failure may be due to the patients' genetic variability of FNTB. Therefore, our results may encourage retrospective evaluation of FNTB polymorphisms in previous FTI studies, especially those reporting positive FTI response.

Function and regulation of MTA1 and MTA3 in malignancies of the female reproductive system

The family of metastasis-associated (MTA) genes is a small group of transcriptional co-regulators which are involved in various physiological functions, ranging from lymphopoietic cell differentiation to the development and maintenance of epithelial cell adhesions. By recruiting histone-modifying enzymes to specific promoter sequences, MTA proteins can function both as transcriptional repressors and activators of a number of cancer-relevant proteins, including Snail, E-cadherin, signal transducer and activator of transcriptions (STATs), and the estrogen receptor. Their involvement in the epithelial-mesenchymal transition process and regulatory interactions with estrogen receptor activity has made MTA proteins highly interesting research candidates, especially in the field of hormone-sensitive breast cancer and malignancies of the female reproductive tract. This review focuses on the current knowledge about the function and regulation of MTA1 and MTA3 proteins in gynecological cancer, including ovarian, endometrial, and cervical tumors.

Circulating U2 small nuclear RNA fragments as a novel diagnostic tool for patients with epithelial ovarian cancer

BACKGROUND

Ovarian cancer is the leading cause of death among malignancies in women. Despite advances in treatment, >50% of patients relapse. For disease monitoring, the identification of a blood-based biomarker would be of prime interest. In this regard, noncoding RNAs, such as microRNA (miRNA) or small nuclear RNA (snRNA), have been suggested as biomarkers for noninvasive cancer diagnosis. In the present study, we sought to identify differentially expressed miRNA/snRNA in sera of ovarian cancer patients and investigate their potential to aid in therapy monitoring.

METHODS

miRNA/snRNA abundance was investigated in serum (n = 10) by microarray analysis and validated in an extended serum set (n = 119) by reverse-transcription quantitative PCR.

RESULTS

Abundance of U2-1 snRNA fragment (RNU2-1f) was significantly increased in sera of ovarian cancer patients (P < 0.0001) and paralleled International Federation of Gynecology and Obstetrics stage as well as residual tumor burden after surgery (P < 0.0001 and P = 0.011, respectively). Moreover, for patients with suboptimal debulking, preoperative RNU2-1f concentration was associated with radiographic response after chemotherapy and with platinum resistance (P = 0.0088 and P = 0.0015, respectively). Interestingly, according to the RNU2-1f abundance dynamics, persistent RNU2-1f positivity before surgery and after chemotherapy identified a subgroup of patients with high risk of recurrence and poor prognosis.

CONCLUSIONS

This is the first report to suggest that a circulating snRNA can serve as an auxiliary diagnostic tool for monitoring tumor dynamics in ovarian cancer. Our results provide a rationale to further investigate whether this high-risk patient group may benefit from additional therapies that are directly applied after chemotherapy.

The IL-18 antagonist IL-18-binding protein is produced in the human ovarian cancer microenvironment

PURPOSE

Interleukin (IL)-18 is an immune-enhancing cytokine, which induces IFN-γ production, T-helper 1 responses, and antitumor effects. In turn, IFN-γ stimulates IL-18-binding protein production, which blocks IL-18 activity. In view of the potential use of IL-18 in epithelial ovarian cancer (EOC) immunotherapy, here, we studied IL-18BP expression and its regulation by cytokines in EOC cells in vitro and in vivo.

EXPERIMENTAL DESIGN

Expression and production of IL-18BP in EOC cell lines, primary ovarian carcinomas, and the corresponding normal tissues, patients' serum, and ascites were investigated by immunochemistry, ELISA, screening of gene expression profiles, and reverse-transcription PCR.

RESULTS

Analysis of gene expression profiles revealed that IL18BP mRNA is increased in EOC tumors compared with normal ovary cells. Release of IL-18BP was detectable in EOC sera and to a greater extent in the ascites, indicating production at the tumor site. Indeed, immunochemical analyses on cells isolated from the ascites and on tumor sections indicated that IL-18BP is expressed in both tumor cells and tumor-associated leukocytes, which displayed a CD3-CD20-NKp46-CD13+CD14low phenotype. EOC cell lines do not constitutively express IL-18BP. However, its release is inducible both by IFN-γ stimulation in vitro and by xenotransplantation of EOC cells in immune-deficient mice, suggesting a role for the microenvironment. In vitro experiments and immunochemistry indicated that IL-27 is also involved in IL-18BP upregulation in EOC cell lines and primary cells through STAT1 activation. Together, these data indicate that IL-18BP, which is produced in EOC in response to microenvironmental factors, may inhibit endogenous or exogenous IL-18 activity.

Characterization of disease progression in ovarian cancer by utilizing 'chemograms' of ovarian cancer stem cells

INTRODUCTION

Ovarian cancer is one of the leading causes of death in women with cancer. First-line chemotherapy with platinum compounds and taxane compounds has been effective, but most patients develop a relapse of the disease due to drug resistance. There is growing evidence that this resistance may be due to the presence of ovarian cancer stem cells.

DISCUSSION

Cells with properties of cancer stem cells have been isolated from the ascitic fluid of ovarian cancer patients. This subset of cells is highly tumourigenic compared to the rest of the cells in the ascitic fluid. They are known to exude harmful chemicals from their cytoplasm and have been found to be resistant to chemotherapeutic agents. This property has been utilized to purify them by fluorescence assisted cytometry to yield a subset of cells which are called 'side population'. These cells exhibit the properties of cancer stem cells and their role in disease progression is being currently investigated. The course of the disease can be potentially characterized at the cellular level by closely studying this cell population. They can also be cultured in different combinations of chemotherapeutic agents at varying concentrations to obtain 'chemograms' which are sensitivity charts. Chemotherapeutic agents which produce the most effective kill curves can then be rationally used as a second-line chemotherapy if the disease relapses. These sensitivity charts can provide insight into emerging patterns of chemoresistance and also help discover surface markers that accurately identify ovarian cancer stem cells.

CONCLUSION

The high rate of disease relapse in patients with ovarian cancer requires a new and different approach utilizing the sensitivity of cancer stem cells. Isolating and characterizing the resistance patterns of ovarian cancer stem cells may provide a rational approach towards an effective and individualized chemotherapeutic regimen.

Advanced ovarian cancer: Neoadjuvant chemotherapy plus surgery and HIPEC as up-front treatment

Epithelial ovarian cancer (EOC) is one of the most common malignancies and one of the principal causes of death in gynecological neoplasms. The majority of EOC patients present with an advanced International Federation of Gynecology and Obstetrics stage disease. The current standard treatment for these patients consists of complete cytoreduction and combined systemic chemotherapy of a platinum agent and paclitaxel. Even if the majority of patients with EOC respond to first-line platinum based chemotherapy, almost 20% of them are resistant or refractory. According to these data, the main risk is for a certain number of patients to have undergone cytoreductive surgery (CRS) and subsequent hyperthermic intraoperative peritoneal chemotherapy (HIPEC) in a useful way. Radical surgery, especially in advanced cases, is associated with a high incidence of postoperative morbidity and mortality, which could be increased by the HIPEC. Every effort should be made for previously selected patients to improve outcome and optimize resources. Over the last decade, new options have been introduced to prolong survival. Improved long-term results can be achieved using CRS in combination with intraoperative HIPEC. This combination has also been used in an up-front setting. Controversial outcomes have been reported for neoadjuvant platinum-based chemotherapy. Different papers have been published reporting discordant results. Further studies are needed.

Efficient inhibition of intraperitoneal ovarian cancer growth in nude mice by liposomal delivery of short hairpin RNA against STAT3

AIM

Signal transducer and activator of transcription 3 (STAT3) plays an important role in the tumor formation, prognosis and chemoresistance of ovarian cancer. Our goal was to investigate the effect of silencing STAT3 on ovarian cancer cell apoptosis, proliferation, angiogenesis and expression of key targets in vitro and in vivo.

METHODS

The ovarian cancer cell lines A2780CP and A2780s were used. STAT3 was knocked down by the plasmid-based short hairpin RNA (shRNA) expression system. In vitro, a colony formation assay and Hoechst staining were used to examine cell proliferation and apoptosis. The expression level of STAT3 and apoptosis-related proteins were determined by Western blot. The A2780CP intraperitoneal model was used to evaluate the effect of shSTAT3 on tumor growth in mice. Proliferation, apoptosis, and angiogenesis in tumor tissues were measured by proliferating cell nuclear antigen, TUNEL and CD31 immunostaining, respectively.

RESULTS

Treatment with shSTAT3 resulted in apoptosis and inhibition of cell proliferation in vitro. Western blot analysis demonstrated that shSTAT3 induced the expression of cleaved caspase-3 and reduced the expression of survivin, Bcl-2 and vascular endothelial growth factor. In vivo, the tumor weight was reduced to 13.46% of 5% glucose by shSTAT3/lipoplexes (P < 0.01), accompanied with apoptosis induction (P < 0.01), proliferation inhibition (P < 0.01) and angiogenesis inhibition (P < 0.01).

CONCLUSIONS

We find that treatment with shSTAT3 inhibits tumor growth in vitro and in vivo by inducing apoptosis and inhibiting cell proliferation. This work should provide the scientific foundation for future investigation of shSTAT3 as a strategy for ovarian cancer gene therapy and the combination of gene therapy with chemotherapy.

Photoimmunotherapy and irradiance modulation reduce chemotherapy cycles and toxicity in a murine model for ovarian carcinomatosis: perspective and results

Significant toxicities from multiple cycles of chemotherapy often cause delays or early termination of treatment, leading to poor outcomes in ovarian cancer patients. Complementary modalities that potentiate the efficacy of traditional agents with fewer cycles and less toxicity are needed. Photodynamic therapy is a mechanistically-distinct modality that synergizes with chemo and biologic agents. A combination regimen with a clinically relevant chemotherapy cocktail (cisplatin + paclitaxel) and anti-EGFR targeted photoimmunotherapy (PIT) is evaluated in a murine model for ovarian carcinomatosis. Mice received either 1 or 2 chemotherapy cycles followed by PIT with a chlorine6-Erbitux photoimmunoconjugate and 25 J/cm2 light. PIT + 1 cycle of chemotherapy significantly reduced tumor burden, comparable to multiple chemotherapy cycles. Relative to 1 cycle of chemotherapy, the addition of PIT did not cause significant mouse weight loss, whereas 2 cycles of chemotherapy led to a significant reduction in weight. Irradiance-dependence on PIT efficacy was a function of the conjugation chemistry, providing an additional variable for optimization of PIT outcome.

IKK-ε coordinates invasion and metastasis of ovarian cancer

Inhibitor of IκB kinases (IKK) are key regulators of NF-κB signaling. Three IKK isoforms-α, β, and ε-have been linked to oncogenesis, yet the precise components of NF-κB signaling in ovarian cancer have not yet been dissected. We surveyed 120 ovarian cancer specimens for IKK-ε expression. Notably, cytoplasmic expression was elevated in metastatic lesions relative to primary tumors (P = 0.03). Therefore, we hypothesized that IKK-ε drives ovarian cancer metastasis. IKK-ε was identified previously as a breast cancer oncogene and was associated with poor clinical outcome in ovarian cancer. We now define an ovarian cancer-specific IKK-ε-regulated gene expression signature using stably expressed short hairpin RNA targeting IKK-ε. Pathway analysis of the signature indicated that IKK-ε regulates expression of genes involved in cell motility and inflammation. We further showed that IKK-ε depletion in metastatic ovarian cancer cell lines decreased growth, adhesion, and invasion. Consistently, human xenografts depleted of IKK-ε in mice showed decreased aggressiveness, whereas overexpression of IKK-ε in a less invasive ovarian cancer cell line increased metastasis in vivo. Taken together, these data provide evidence that IKK-ε is a key coordinator of invasion and metastasis programs in ovarian cancer. Inhibition of IKK-ε signaling thus emerges as a viable therapeutic strategy in women whose ovarian cancer shows aberrant activation of this pathway.

LOH at 6q and 10q in fractionated circulating DNA of ovarian cancer patients is predictive for tumor cell spread and overall survival

Background

We recently showed that LOH proximal to M6P/IGF2R locus (D6S1581) in primary ovarian tumors is predictive for the presence of disseminated tumor cells (DTC) in the bone marrow (BM). For therapy-monitoring, it would be highly desirable to establish a blood-based biomarker. Therefore, we quantified circulating DNA (cirDNA) in sera of 63 ovarian cancer patients before surgery and after chemotherapy, measured incidence of LOH at four cancer-relevant chromosomal loci, correlated LOH with tumor cell spread to the BM and evaluated prognostic significance of LOH.

Methods

cirDNA was fractionated into high- and low molecular-weight fraction (HMWF, LMWF) for LOH-profiling, utilizing PCR-based fluorescence microsatellite analysis. BM aspirates were analyzed for DTC by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3.

Results

cirDNA levels in the HMWF before surgery were predictive for residual tumor load (p = 0.017). After chemotherapy, we observed a significant decline of cirDNA in the LMWF (p = 0.0001) but not in the HMWF. LOH was prevalently detected in the LMWF with an overall frequency of 67%, only moderately ablating after chemotherapy (45%). Before surgery, LOH in the LMWF at marker D10S1765 and D13S218 significantly correlated with tumor grading and FIGO stage (p = 0.033, p = 0.004, respectively). In both combined fractions, LOH at D6S1581 additionally associated with overall survival (OS) (p = 0.030). Moreover, solely LOH at D10S1765 in LMWF after therapy correlated with DTC in BM after therapy (p = 0.017).

Conclusion

We demonstrate the applicability and necessity of DNA-fractionation prior to analyzing circulating LOH and identify LOH at D10S1765 and D6S1581 as novel blood-based biomarkers for ovarian cancer, being relevant for therapy-monitoring.

In vivo selection of autologous MGMT gene-modified cells following reduced-intensity conditioning with BCNU and temozolomide in the dog model

Chemotherapy with 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) and temozolomide (TMZ) is commonly used for the treatment of glioblastoma multiforme (GBM) and other cancers. In preparation for a clinical gene therapy study in patients with glioblastoma, we wished to study whether these reagents could be used as a reduced-intensity conditioning regimen for autologous transplantation of gene-modified cells. We used an MGMT(P140K)-expressing lentivirus vector to modify dog CD34(+) cells and tested in four dogs whether these autologous cells engraft and provide chemoprotection after transplantation. Treatment with O(6)-benzylguanine (O6BG)/TMZ after transplantation resulted in gene marking levels up to 75%, without significant hematopoietic cytopenia, which is consistent with hematopoietic chemoprotection. Retrovirus integration analysis showed that multiple clones contribute to hematopoiesis. These studies demonstrate the ability to achieve stable engraftment of MGMT(P140K)-modified autologous hematopoietic stem cells (HSCs) after a novel reduced-intensity conditioning protocol using a combination of BCNU and TMZ. Furthermore, we show that MGMT(P140K)-HSC engraftment provides chemoprotection during TMZ dose escalation. Clinically, chemoconditioning with BCNU and TMZ should facilitate engraftment of MGMT(P140K)-modified cells while providing antitumor activity for patients with poor prognosis glioblastoma or alkylating agent-sensitive tumors, thereby supporting dose-intensified chemotherapy regimens.

Pilot study: alteration of deleted in liver cancer1 and phosphorylated focal adhesion kinase Y397 cytoplasmic expression and the prognostic value in advanced epithelial ovarian carcinoma

Background

Deletion in liver cancer gene (DLC1) and phosphorylated focal adhesion kinase (p-FAK) have recently been reported as metastasis-related genes. However, the roles and prognostic values of their expression in epithelial ovarian carcinomas (EOCs) remain unclear.

Methods

The expression and prognostic value of DLC1 and p-FAK Y397 in EOC were evaluated by immunohistochemistry and multivariate analysis.

Results

Low expression of DLC1 and high expression of p-FAK Y397 were found in the 76 cases of EOC. The expression of DLC1 and p-FAK Y397 were negatively correlated. Multivariate analysis showed that the combination of them was an independent prognostic marker of EOC (P = 0.0319).

Conclusions

DLC1 and pFAK Y397 had an association with the clinicopathologic characteristics of EOC. Expression of neither of these genes was a prognostic factor alone, but the combination revealed a significant prognostic value in the 60 cases of advanced stage EOC.

Fractalkine receptor CX(3)CR1 is expressed in epithelial ovarian carcinoma cells and required for motility and adhesion to peritoneal mesothelial cells

Epithelial ovarian carcinoma (EOC) is a deadly disease, and little is known about the mechanisms underlying its metastatic progression. Using human specimens and established cell lines, we determined that the G-protein-coupled seven-transmembrane fractalkine receptor (CX(3)CR1) is expressed in primary and metastatic ovarian carcinoma cells. Ovarian carcinoma cells robustly migrated toward CX(3)CL1, a specific ligand of CX(3)CR1, in a CX(3)CR1-dependent manner. Silencing of CX(3)CR1 reduced migration toward human ovarian carcinoma ascites fluid by approximately 70%. Importantly, adhesion of ovarian carcinoma cells to human peritoneal mesothelial cells was dependent on CX(3)CL1/CX(3)CR1 signaling. In addition, CX(3)CL1 was able to induce cellular proliferation. Together, our data suggest that the fractalkine network may function as a major contributor to the progression of EOC, and further attention to its role in the metastasis of this deadly malignancy is warranted.