Peritoneal tumor spread in serous ovarian cancer-epithelial mesenchymal status and outcome

YAP signaling orchestrates the endothelin-1-guided invadopodia formation in high-grade serous ovarian cancer

The high-grade serous ovarian cancer (HG-SOC) is a notoriously challenging disease, characterized by a rapid peritoneal dissemination. HG-SOC cells leverage actin-rich membrane protrusions, known as invadopodia, to degrade the surrounding extracellular matrix (ECM) and invade, initiating the metastatic cascade. In HG-SOC, the endothelin-1 (ET-1)/endothelin A receptor (ETAR)-driven signaling coordinates invadopodia activity, however how this axis integrates pro-oncogenic signaling routes, as YAP-driven one, impacting on the invadopodia-mediated ECM degradation and metastatic progression, deserves a deeper investigation. Herein, we observed that downstream of the ET-1/ET-1R axis, the RhoC and Rac1 GTPases, acting as signaling intermediaries, promote the de-phosphorylation and nuclear accumulation of YAP. Conversely, the treatment with the dual ETA/ETB receptor antagonist, macitentan, inhibits the ET-1-driven YAP activity. Similarly, RhoC silencing, or cell transfection with a dominant inactive form of Rac1, restores YAP phosphorylation. Mechanistically, the ET-1R/YAP signal alliance coordinates invadopodia maturation into ECM-degrading structures, indicating how such ET-1R-guided protein network represents a route able to enhance the HG-SOC invasive potential. At functional level, we found that the interconnection between the ET-1R/RhoC and YAP signals is required for MMP-2 and MMP-9 proteolytic functions, cell invasion, and cytoskeleton architecture changes, supporting the HG-SOC metastatic strength. In HG-SOC patient-derived xenografts (PDX) macitentan, turning-off the invadopodia regulators RhoC/YAP, halts the metastatic colonization. ET-1R targeting, hindering the YAP activity, weakens the invadopodia machinery, embodying a promising therapeutic avenue to prevent peritoneal dissemination in HG-SOC.

Stratification of Homologous Recombination Deficiency-Negative High-Grade Ovarian Cancer by the Type of Peritoneal Spread into Two Groups with Distinct Survival Outcomes

BACKGROUND

Homologous recombination deficiency (HRD) has evolved into a major diagnostic marker in high-grade ovarian cancer (HGOC), predicting the response to poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPi) and also platinum-based therapy. In addition to HRD, the type of peritoneal tumor spread influences the treatment response and patient survival; miliary type tumor spread has a poorer predicted outcome than non-miliary type tumor spread.

METHODS

Known methods for HRD assessment were adapted for our technical requirements and the predictive-value integrated genomic instability score (PIGIS) for HRD assessment evolved as an outcome. PIGIS was validated in HGOC samples from 122 patients. We used PIGIS to analyze whether the type of tumor spread correlated with HRD status and whether this had an impact on survival.

RESULTS

We demonstrated that PIGIS can discriminate HRD-positive from HRD-negative samples. Tumors with a miliary tumor spread are HRD-negative and have a very bad prognosis with a progression-free survival (PFS) of 15.6 months and an overall survival (OS) of 3.9 years. However, HRD-negative non-miliary spreading tumors in our cohort had a much better prognosis (PFS 35.4 months, OS 8.9 years); similar to HRD-positive tumors (PFS 34.7 months, OS 8.9 years).

CONCLUSIONS

Our results indicate that in a predominantly PARPi naïve cohort, the type of tumor spread and concomitant cytoreduction efficiency is a better predictor of survival than HRD and that HRD may be an accidental surrogate marker for tumor spread and concomitant cytoreduction efficiency. It remains to be determined whether this also applies for sensitivity to PARPi.

A Recipe for Successful Metastasis: Transition and Migratory Modes of Ovarian Cancer Cells

One of the characteristic features of ovarian cancer is its early dissemination. Metastasis and the invasiveness of ovarian cancer are strongly dependent on the phenotypical and molecular determinants of cancer cells. Invasive cancer cells, circulating tumor cells, and cancer stem cells, which are responsible for the metastatic process, may all undergo different modes of transition, giving rise to mesenchymal, amoeboid, and redifferentiated epithelial cells. Such variability is the result of the changing needs of cancer cells, which strive to survive and colonize new organs. This would not be possible if not for the variety of migration modes adopted by the transformed cells. The most common type of metastasis in ovarian cancer is dissemination through the transcoelomic route, but transitions in ovarian cancer cells contribute greatly to hematogenous and lymphatic dissemination. This review aims to outline the transition modes of ovarian cancer cells and discuss the migratory capabilities of those cells in light of the known ovarian cancer metastasis routes.

Immunosuppressive M2 TAMs represent a promising target population to enhance phagocytosis of ovarian cancer cells in vitro

Introduction

Tumor-associated macrophages (TAMs) represent an important cell population within the tumor microenvironment, but little is known about the phenotype and function of these cells. The present study aims to characterize macrophages in high-grade serous ovarian cancer (HGSOC).

Methods

Phenotype and expression of co-regulatory markers were assessed on TAMs derived from malignant ascites (MA) or peripheral blood (PB) by multiparametric flow cytometry. Samples were obtained from HGSOC patients (n=29) and healthy donors (HDs, n=16). Additional expression analysis was performed by RNAseq (n=192). Correlation with clinically relevant parameters was conducted and validated by a second patient cohort (n=517). Finally, the role of TIGIT in repolarization and phagocytosis was investigated in vitro.

Results

Expression of the M2-associated receptors CD163, CD204, and CD206, as well as of the co-regulatory receptors TIGIT, CD226, TIM-3, and LAG-3 was significantly more frequent on macrophages in HGSOC than in HDs. CD39 and CD73 were broadly expressed on (mainly M2) macrophages, but without a clear clustering in HGSOC. CD163 mRNA levels were higher in TAMs from patients with residual tumor mass after surgery and associated with a shorter overall survival. In addition, TIGIT expression was associated with a higher tumor grading, indicating a prognostic relevance of M2 infiltration in HGSOC. TIGIT blockade significantly reduced the frequency of M2 macrophages. Moreover, combined blockade of TIGIT and CD47 significantly increased phagocytosis of ovarian cancer cells by TAMs in comparison to a single blockade of CD47.

Conclusion

Combined blockade of TIGIT and CD47 represents a promising approach to enhance anti-CD47-facilitated phagocytosis.

Recurrence and 5-year survival rate in patients with borderline ovarian tumors and related factors in Kurdistan

The aim of this study was to investigate the recurrence rate and five-year survival in patients with borderline ovarian tumors and related factors. This retrospective cohort study was performed on 20 women diagnosed with a borderline ovarian tumor in Kurdistan province, Iran, between 2007 and 2019. Patients' records were reviewed and a researcher-made questionnaire was completed for each patient, which included demographic and clinical variables related to patient survival. The most common type of ovarian borderline tumor was the serous borderline ovarian tumor (75%). In fifty percent of the cases, cystectomy was used as th treatment. Recurrence was observed in three patients (15%), two of which were treated with cystectomy, and the other case was treated by TAH + BSO method (p = 0.64). There was no significant difference in terms of the type of surgery, history of infertility, history of taking contraceptive pills, age, age at diagnosis, and BMI between the two groups with and without recurrence (p > 0.05). The overall survival rate was 100% and none of the patients died at the end of follow-up. There was no relationship between any of the clinical and demographic variables with disease recurrence, and since all patients were alive after the end of the follow-up period. In summary, it was not possible to assess the relationship between patients' survival rate and studied variables.

Peritoneal Metastasis: Current Status and Treatment Options

Simple Summary

Surgical and locoregional treatments of peritoneal metastasis, e.g., from colorectal cancer, has gained increasing acceptance after the publication of excellent patient outcomes from many groups around the world. Apart from systemic chemotherapy and surgical removal of the tumor, locoregional therapies such as HIPEC or PIPAC may improve tumor control. Understanding the molecular characteristics of peritoneal metastasis is crucial to evolve future therapeutic strategies for peritoneal metastasis. This includes the genetic background of PM, which is often different from other sites of metastasis, and promotes peritoneal dissemination and the growth of tumor cells. Growing knowledge and insight into the physiology of the peritoneal tumor microenvironment and the specific role of the immune system in this compartment may provide a critical step to move locoregional therapy to the next level. This review summarizes the current knowledge and highlights the molecular characteristics of peritoneal metastasis.

Abstract

Peritoneal metastasis (PM) originating from gastrointestinal cancer was considered a terminal disease until recently. The advent of better systemic treatment, a better understanding of prognostic factors, and finally, the advent of novel loco-regional therapies, has opened the door for the multimodal treatment of PM. These strategies, including radical surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) showed surprisingly good results, leading to the prolonged survival of patients with peritoneal metastasis. This has triggered a significant body of research, leading to the molecular characterization of PM, which may further help in the development of novel treatments. This review summarizes current evidence on peritoneal metastasis and explores potential novel mechanisms and therapeutic approaches to treat patients with peritoneal metastasis.

Modeling High-Grade Serous Ovarian Carcinoma Using a Combination of In Vivo Fallopian Tube Electroporation and CRISPR-Cas9-Mediated Genome Editing

Ovarian cancer is the most lethal gynecologic cancer to date. High-grade serous ovarian carcinoma (HGSOC) accounts for most ovarian cancer cases, and it is most frequently diagnosed at advanced stages. Here, we developed a novel strategy to generate somatic ovarian cancer mouse models using a combination of in vivo electroporation and CRISPR-Cas9-mediated genome editing. Mutation of tumor suppressor genes associated with HGSOC in two different combinations (Brca1, Tp53, Pten with and without Lkb1) resulted in successfully generation of HGSOC, albeit with different latencies and pathophysiology. Implementing Cre lineage tracing in this system enabled visualization of peritoneal micrometastases in an immune-competent environment. In addition, these models displayed copy number alterations and phenotypes similar to human HGSOC. Because this strategy is flexible in selecting mutation combinations and targeting areas, it could prove highly useful for generating mouse models to advance the understanding and treatment of ovarian cancer. SIGNIFICANCE: This study unveils a new strategy to generate genetic mouse models of ovarian cancer with high flexibility in selecting mutation combinations and targeting areas.

The pattern of peritoneal colorectal metastasis predicts survival after cytoreductive surgery and hyperthermic intra-peritoneal chemotherapy

BACKGROUND

Peritoneal cancer index (PCI) has been used reliably to prognosticate patients with peritoneal metastasis, however, it fails to describe the patterns of peritoneal spread and to correlate these patterns to survival outcomes. We aim to define the scattered peritoneal spread (SPS) as a pattern associated with worse survival in colorectal peritoneal metastasis.

METHODS

A retrospective analysis of metastatic colorectal cancer patients from a prospectively maintained database of peritoneal surface malignances (n = 280) between 2015 and 2020. SPS was defined by the presence of at least two distant and non-contiguous PCI regions. We compared patients with SPS (n = 73) and clustered peritoneal spread (CPS) (n = 88) for demographics, perioperative and survival outcomes.

RESULTS

No difference in demographics or post-operative course was noted between the groups. The median follow-up was 15.4 months (0.4-70.8 months). Worse disease-free survival (DFS) in the SPS group with an estimated median of 8.2 months compared to 22.5 months in the CPS spread group, (p = 0.001). The estimated median overall survival (OS) for SPS group was 35.7 months whereas in the CPS group the median was not reached (p = 0.025). The same effect of SPS was preserved even after stratification of PCI.

CONCLUSIONS

We defined and described the association of the peritoneal spread pattern to survival outcomes. SPS patients exhibit worse DFS and OS independent of the PCI level. Integration of malignant spread pattern into prognostication models along with PCI may aid in predicting oncological outcomes.

TGFβ signaling networks in ovarian cancer progression and plasticity

Epithelial ovarian cancer (EOC) is a leading cause of cancer-related death in women. Late-stage diagnosis with significant tumor burden, accompanied by recurrence and chemotherapy resistance, contributes to this poor prognosis. These morbidities are known to be tied to events associated with epithelial-mesenchymal transition (EMT) in cancer. During EMT, localized tumor cells alter their polarity, cell-cell junctions, cell-matrix interactions, acquire motility and invasiveness and an exaggerated potential for metastatic spread. Key triggers for EMT include the Transforming Growth Factor-β (TGFβ) family of growth factors which are actively produced by a wide array of cell types within a specific tumor and metastatic environment. Although TGFβ can act as either a tumor suppressor or promoter in cancer, TGFβ exhibits its pro-tumorigenic functions at least in part via EMT. TGFβ regulates EMT both at the transcriptional and post-transcriptional levels as outlined here. Despite recent advances in TGFβ based therapeutics, limited progress has been seen for ovarian cancers that are in much need of new therapeutic strategies. Here, we summarize and discuss several recent insights into the underlying signaling mechanisms of the TGFβ isoforms in EMT in the unique metastatic environment of EOCs and the current therapeutic interventions that may be relevant.

PD-1 and PD-L1 expression on TILs in peritoneal metastases compared to ovarian tumor tissues and its associations with clinical outcome

The therapeutic potential of immune checkpoint inhibitors is currently being investigated in epithelial ovarian cancer (EOC), but immunological effects of the programmed cell death protein 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) axis in EOC still remain poorly understood. The aim of this study was thus to compare infiltration rates of PD-1 and PD-L1 expressing tumor infiltrating leucocytes (TILs) in primary ovarian tumor tissue and metastatic intraperitoneal implants and to investigate its impact on overall survival (OS). Tumor specimens (ovarian tumor tissues and intraperitoneal metastases) of 111 patients were used to investigate the PD-1, PD-L1 and CD8 expression rates on TILs and PD-L1 expression rate of tumor cells. The percentages of CD8, PD-1, and PD-L1 expressing subpopulations of TILs differ in primary ovarian tumor tissues and metastatic intraperitoneal implants. High PD-1 among TILs in peritoneal metastases were associated with favorable OS. High PD-L1 expression in TILs was associated with poor OS. Combining both factors in peritoneal metastases revealed an unfavorable prognosis. Primary ovarian tumor tissue and intraperitoneal metastatic tissues in EOC might have different strategies to evade immune control. Those findings are of importance for the process of biomarker assessment to predict patients’ response to immunotherapy.

A Global Gene Body Methylation Measure Correlates Independently with Overall Survival in Solid Cancer Types

Epigenetics, CpG methylation of CpG islands (CGI) and gene bodies (GBs), plays an important role in gene regulation and cancer biology, the former established as a transcription regulator. Genome wide CpG methylation, summarized over GBs and CGIs, was analyzed for impact on overall survival (OS) in cancer. The averaged GB and CGI methylation status of each gene was categorized into methylated and unmethylated (defined) or undefined. Differentially methylated GBs and genes associated with their GB methylation status were compared to the corresponding CGI methylation states and biologically annotated. No relevant correlations of GB and CGI methylation or GB methylation and gene expression were observed. Summarized GB methylation showed impact on OS in ovarian, breast, colorectal, and pancreatic cancer, and glioblastoma, but not in lung cancer. In ovarian, breast, and colorectal cancer more defined GBs correlated with unfavorable OS, in pancreatic cancer with favorable OS and in glioblastoma more methylated GBs correlated with unfavorable OS. The GB methylation of genes were similar over different samples and even over cancer types; nevertheless, the clustering of different cancers was possible. Gene expression differences associated with summarized GB methylation were cancer specific. A genome-wide dysregulation of gene-body methylation showed impact on the outcome in different cancers.

Enlarged cardiophrenic lymph nodes predict disease involvement of the upper abdomen and the outcome of primary surgical debulking in advanced ovarian cancer

INTRODUCTION

The outcome of ovarian cancer patients is highly dependent on the success of primary debulking surgery in terms of postoperative residual disease. This study critically evaluates the clinical impact of preoperative radiologic assessment of the cardiophrenic lymph node (CPLN) status in advanced ovarian cancer.

MATERIAL AND METHODS

Baseline CT scans of 178 stage III and IV ovarian cancer patients were retrospectively reviewed by two independent radiologists. CPLN enlargement defined at a short-axis ≥5 mm was evaluated for its prognostic value and predictive power of upper abdominal tumor involvement and the chance of complete intra-abdominal tumor resection at primary debulking surgery. Only patients without surgically removed CPLN were eligible for this study.

RESULTS

Enlarged CPLNs were detected in 50% of patients and correlated with radiologically suspicious (P = .028) and histologically confirmed (P = .001) paraaortic lymph node metastases. CPLNs ≥ 5 mm were associated with high CA-125 levels at baseline and revealed independent prognostic relevance for progression-free survival (hazard ratio [HR] 2.14, 95% confidence interval [CI] 1.33-3.42) and overall survival (HR 2.18, 95% CI 1.16-4.08). Noteworthy, patients with enlarged CPLNs nonetheless benefit from complete intra-abdominal tumor debulking in terms of an improvement in progression-free survival (HR 0.60, 95% CI 0.38-0.94) and overall survival (HR 0.59, 95% CI 0.35-0.82). Enlarged CPLNs correctly predicted carcinomatosis of the upper abdomen in 94.6%. A predictive score of complete tumor debulking, termed CD-score, which integrates, beside a CPLN short axis <5 mm, an ascites volume <500 mL, and CA-125 levels <500 U/mL at baseline, correctly predicted complete intra-abdominal debulking in 100% of patients.

CONCLUSIONS

CPLNs ≥5 mm predict upper abdominal tumor involvement. The application of the CD-score predicted complete macroscopic tumor resection at primary surgery in all of the patients. Although, CPLN pathology suggests extra-abdominal disease, we consistently demonstrated that patients nonetheless benefit from complete intra-abdominal tumor resection.

Neutrophil Extracellular Trap Formation Correlates with Favorable Overall Survival in High Grade Ovarian Cancer

It is still a question of debate whether neutrophils, often found in the tumor microenvironment, mediate tumor-promoting or rather tumor-inhibiting activities. The present study focuses on the involvement of neutrophils in high grade serous ovarian cancer (HGSOC). Macroscopic features classify two types of peritoneal tumor spread in HGSOC. Widespread and millet sized lesions characterize the miliary type, while non-miliary metastases are larger and associated with better prognosis. Multi-omics and FACS data were generated from ascites samples. Integrated data analysis demonstrates a significant increase of neutrophil extracellular trap (NET)-associated molecules in non-miliary ascites samples. A co-association network analysis performed with the ascites data further revealed a striking correlation between NETosis-associated metabolites and several eicosanoids. The congruence of data generated from primary neutrophils with ascites analyses indicates the predominance of NADPH oxidase 2 (NOX)-independent NETosis. NETosis is associated with protein S100A8/A9 release. An increase of the S100A8/CRP abundance ratio was found to correlate with favorable survival of HGSOC patients. The analysis of additional five independent proteome studies with regard to S100A8/CRP ratios confirmed this observation. In conclusion, NET formation seems to relate with better cancer patient outcome.

Novel strategy of ovarian cancer implantation: Pre-invasive growth of fibrin-anchored cells with neovascularization

Although direct adhesion of cancer cells to the mesothelial cell layer is considered to be a key step for peritoneal invasion of ovarian cancer cell masses (OCM), we recently identified a different strategy for the peritoneal invasion of OCM. In 6 out of 20 cases of ovarian carcinoma, extraperitoneal growth of the OCM was observed along with the neovascularization of feeding vessels, which connect the intraperitoneal host stroma and extraperitoneal lesions through the intact mesothelial cell layer. As an early step, the OCMs anchor in the extraperitoneal fibrin networks and then induce the migration of CD34-positive and vascular endothelial growth factor A (VEGF-A)-positive endothelial cells, constructing extraperitoneal vascular networks around the OCM. During the extraperitoneal growth of OCM, podoplanin-positive and α smooth muscle actin (αSMA)-positive cancer-associated fibroblasts (CAF) appears. In more advanced lesions, the boundary line of mesothelial cells disappears around the insertion areas of feeding vessels and then extraperitoneal and intraperitoneal stroma are integrated, enabling the OCM to invade the host stroma, being associated with CAF. In addition, tissue factors (TF) are strongly detected around these peritoneal implantation sites and their levels in ascites were higher than that in blood. These findings demonstrate the presence of neovascularization around fibrin net-anchored OCMs on the outer side of the intact peritoneal surface, suggesting a novel strategy for peritoneal invasion of ovarian cancer and TF-targeted intraperitoneal anti-cancer treatment. We observed and propose a novel strategy for peritoneal implantation of ovarian cancer. The strategy includes the preinvasive growth of fibrin-anchored cancer cells along with neovascularization on the outer side of the intact peritoneal surface.

NECTIN4 (PVRL4) as Putative Therapeutic Target for a Specific Subtype of High Grade Serous Ovarian Cancer-An Integrative Multi-Omics Approach

In high grade serous ovarian cancer patients with peritoneal involvement and unfavorable outcome would benefit from targeted therapies. The aim of this study was to find a druggable target against peritoneal metastasis. We constructed a planar-scale free small world-co-association gene expression network and searched for clusters with hub-genes associated to peritoneal spread. Protein expression and impact was validated via immunohistochemistry and correlations of deregulated pathways with comprehensive omics data were used for biological interpretation. A cluster up-regulated in miliary tumors with NECTIN4 as hub-gene was identified and impact on survival validated. High Nectin 4 protein expression was associated with unfavorable survival and (i) reduced expression of HLA genes (mainly MHC I); (ii) with reduced expression of genes from chromosome 22q11/12; (iii) higher BCAM in ascites and in a high-scoring expression cluster; (iv) higher Kallikrein gene and protein expressions; and (v) substantial immunologic differences; locally and systemically; e.g., reduced CD14 positive cells and reduction of different natural killer cell populations. Each three cell lines with high (miliary) or low NECTIN4 expression (non-miliary) were identified. An anti-Nectin 4 antibody with a linked antineoplastic drug-already under clinical investigation-could be a candidate for a targeted therapy in patients with extensive peritoneal involvement.

Ovarian serous carcinoma in synthetic mesh: A rare case report and review of the literature

Epithelial ovarian cancer relapse is a devastating condition with a poor prognosis. Synthetic mesh carcinogenicity is an entity scarcely reported in the literature. We present a rare case of an ovarian serous tumor relapsed in a polypropylene mesh previously inserted for pelvic organ prolapse correction and a review of the available literature. Our case report point to a possible association between synthetic mesh and ovarian cancer relapse.

The Epithelial-Mesenchymal Transition Initiated by Malignant Ascites Underlies the Transmesothelial Invasion of Ovarian Cancer Cells

The role of the epithelial-mesenchymal transition (EMT) in ovarian cancer cell progression is unquestioned. In this report, we describe that malignant ascites, fluid that accumulates in the peritoneal cavity in a large group of patients with ovarian cancer, stimulate EMT in two representative ovarian cancer cell lines (A2780, SKOV-3). In addition, we identify the ascites-derived mediators of EMT and signaling pathways initiated in the cancer cells that underlie this phenomenon. Finally, we demonstrate that EMT induced in the cancer cells in response to the malignant ascites contributes to their increased transmesothelial invasion. Altogether, our study provides new insight into the mechanistic aspects of the malignant ascites-dependent exacerbation of the intraperitoneal progression of ovarian cancer.

Clinical Significance of Organic Anion Transporting Polypeptide Gene Expression in High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is considered the most deadly and frequently occurring type of ovarian cancer and is associated with various molecular compositions and growth patterns. Evaluating the mRNA expression pattern of the organic anion transporters (OATPs) encoded by SLCO genes may allow for improved stratification of HGSOC patients for targeted invention. The expression of SLCO mRNA and genes coding for putative functionally related ABC-efflux pumps, enzymes, pregnane-X-receptor, ESR1 and ESR2 (coding for estrogen receptors ERα and ERß) and HER-2 were assessed using RT-qPCR. The expression levels were assessed in a cohort of 135 HGSOC patients to elucidate the independent impact of the expression pattern on the overall survival (OS). For identification of putative regulatory networks, Graphical Gaussian Models were constructed from the expression data with a tuning parameter K varying between meaningful borders (Pils et al., 2012; Auer et al., 2015, 2017; Kurman and Shih Ie, 2016; Karam et al., 2017; Labidi-Galy et al., 2017; Salomon-Perzynski et al., 2017; Sukhbaatar et al., 2017). The final value used (K = 4) was determined by maximizing the proportion of explained variation of the corresponding LASSO Cox regression model for OS. The following two networks of directly correlated genes were identified: (i) SLCO2B1 with ABCC3 implicated in estrogen homeostasis; and (ii) two ABC-efflux pumps in the immune regulation (ABCB2/ABCB3) with ABCC3 and HER-2. Combining LASSO Cox regression and univariate Cox regression analyses, SLCO5A1 coding for OATP5A1, an estrogen metabolite transporter located in the cytoplasm and plasma membranes of ovarian cancer cells, was identified as significant and independent prognostic factor for OS (HR = 0.68, CI 0.49-0.93; p = 0.031). Furthermore, results indicated the benefits of patients with high expression by adding 5.1% to the 12.8% of the proportion of explained variation (PEV) for clinicopathological parameters known for prognostic significance (FIGO stage, age and residual tumor after debulking). Additionally, overlap with previously described signatures that indicated a more favorable prognosis for ovarian cancer patients was shown for SLCO5A1, the network ABCB2/ABCB3/ABCC4/HER2 as well as ESR1. Furthermore, expression of SLCO2A1 and PGDH, which are important for PGE₂ degradation, was associated with the non-miliary peritoneal tumor spreading. In conclusion, the present findings suggested that SLCOs and the related molecules identified as potential biomarkers in HGSOC may be useful for the development of novel therapeutic strategies.

Prognostic Impact of CEACAM1 in Node-Negative Ovarian Cancer Patients

The underlying mechanisms of ovarian cancer (OvCa) dissemination are still poorly understood, and novel molecular markers for this cancer type are urgently needed. In search of adhesion molecules with prognostic relevance in OvCa, we compared tumors with good outcome (alive > 3 years) and those with poor outcome (dead < 2 years) within data from The Cancer Genome Atlas (TCGA). The carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) turned out as the only gene with differential expression in these groups. In order to further investigation on its role in OvCa, we analyzed CEACAM1 mRNA levels extracted from TCGA microarray data (n = 517) as well as CEACAM1 protein expression by Western blot analysis in a cohort of 242 tumor samples. Further, CEACAM1 localization in tumour tissue was evaluated by immunohistochemistry and CEACAM1 splice variants by RT-PCR in representative tumours. In Kaplan–Meier analysis, high CEACAM1 mRNA levels significantly correlated with longer survival (p = 0.008). By Western blot analysis in the second cohort, similar associations of high CEACAM1 protein levels with longer recurrence-free survival (RFS, p = 0.035) and overall survival (OAS, p = 0.004) were observed. In multivariate Cox regression analysis including clinical prognostic parameters, CEACAM1 mRNA or protein expression turned out as independent prognostic markers. Stratified survival analysis showed that high CEACAM1 protein expression was prognostic in node-negative tumors (p = 0.045 and p = 0.0002 for DFS and OAS) but lost prognostic significance in node-positive carcinomas. Similarly, high CEACAM1 mRNA expression did not show prognostic relevance in tumors with lymphatic invasion (L1) but was associated with longer survival in cases without lymphovascular involvement. Further analysis showed a predominance of 4S and 4L isoforms and mostly membraneous CEACAM1 localization in ovarian tumours. Our results suggest that CEACAM1 might be an independent favorable prognostic marker in OvCa, especially in the subgroup of patients with solely intraperitoneal metastasis.

VEGF-C expression attributes the risk for lymphatic metastases to ovarian cancer patients

Background

Peritoneal dissemination and retroperitoneal lymph node involvement are main routes for progression of epithelial ovarian cancer (EOC). Vascular endothelial growth factor (VEGF) mediated angiogenesis has been identified as an important mechanism promoting tumour progression.

Methods

Tumour tissue of 100 patients with EOC was analysed for protein expression of vascular endothelial growth factor (VEGF)-A, -C, -D by Western Blot analysis. Expression patterns in patients with ‘extensive intraperitoneal’ metastases (pT3c pN1 and pT3b-pT3c pN0, n=80) were compared to patients with ‘predominantly retroperitoneal’ metastases (pT1a-pT3b, pN1, n=20). Overall and progression-free survival was analysed by Kaplan-Meier method.

Results

While no significant differences in expression levels among the different modes of metastases were noted for VEGF-A and -D, VEGF-C expression was significantly higher in the group of predominantly retroperitoneal metastases compared to the group with extensive intraperitoneal metastases. Patients with high VEGF-C expression had a significantly worse overall survival compared to patients with low expression levels.

Conclusions

Retroperitoneal tumour progression in EOC patients is associated with high VEGF-C expression. VEGF-C may serve as a molecular marker to identify patients with assumed high risk for lymphatic metastases, who might benefit from specific treatment strategies.

Role of the immune system in the peritoneal tumor spread of high grade serous ovarian cancer

The immune system plays a critical role in cancer progression and overall survival. Still, it is unclear if differences in the immune response are associated with different patterns of tumor spread apparent in high grade serous ovarian cancer patients and previously described by us. In this study we aimed to assess the role of the immune system in miliary (widespread, millet-sized lesions) and non-miliary (bigger, exophytically growing implants) tumor spread. To achieve this we comprehensively analyzed tumor tissues, blood, and ascites from 41 patients using immunofluorescence, flow cytometry, RNA sequencing, multiplexed immunoassays, and immunohistochemistry. Results showed that inflammation markers were systemically higher in miliary. In contrast, in non-miliary lymphocyte and monocyte/macrophage infiltration into the ascites was higher as well as the levels of PD-1 expression in tumor associated cytotoxic T-lymphocytes and PD-L1 expression in tumor cells. Furthermore, in ascites of miliary patients more epithelial tumor cells were present compared to non-miliary, possibly due to the active down-regulation of anti-tumor responses by B-cells and regulatory T-cells. Summarizing, adaptive immune responses prevailed in patients with non-miliary spread, whereas in patients with miliary spread a higher involvement of the innate immune system was apparent while adaptive responses were counteracted by immune suppressive cells and factors.

Intraperitoneal chemotherapy for ovarian cancer using sustained-release implantable devices

INTRODUCTION

Epithelial ovarian cancer (EOC) remains to be the most lethal of all gynecological malignancies mainly due to its asymptomatic nature. The late stages are manifested with predominant metastases confined to the peritoneal cavity. Although there has been a substantial progress in the treatment avenue with different therapeutic interventions, the overall survival rate of patients remain poor due to relapse and drug resistance.

AREAS COVERED

The pharmacokinetic advantages offered by intraperitoneal (IP) chemotherapy due to peritoneal-plasma barrier can be potentially exploited for EOC relapse treatment. The ability to retain high concentrations of chemo-drugs with high AUC peritoneum/plasma for prolonged durations in the peritoneal cavity can be utilized effectively through the clinical adoption of drug delivery systems (DDSs) which obviates the need for indwelling catheters. The metronomic dosing strategy could enhance anti-tumor efficacy with a continuous, low dose of chemo-drugs providing minimal systemic toxicity.

EXPERT OPINION

The development of a feasible, non-catheter based, IP DDS, retaining the peritoneal-drug levels, with less systemic levels could offer significant survival advantages as a patient-compliant therapeutic strategy. Suturable-implantable devices based on metronomic dosing, eluting drug in a sustained manner at low doses, could be implanted surgically post-debulking for treatment of refractory EOC patients.

Small RNAs and the competing endogenous RNA network in high grade serous ovarian cancer tumor spread

High grade serous ovarian cancer (HGSOC) is among the most deadly malignancies in women, frequently involving peritoneal tumor spread. Understanding molecular mechanisms of peritoneal metastasis is essential to develop urgently needed targeted therapies. We described two peritoneal tumor spread types in HGSOC apparent during surgery: miliary (numerous millet-sized implants) and non-miliary (few big, bulky implants). The former one is defined by a more epithelial-like tumor cell characteristic with less immune cell reactivity and with significant worse prognosis, even if corrected for typical clinicopathologic factors.

23 HGSOC patients were enrolled in this study. Isolated tumor cells from fresh tumor tissues of ovarian and peritoneal origin and from ascites were used for ribosomal RNA depleted RNA and small RNA sequencing. RT-qPCR was used to validate results and an independent cohort of 32 patients to validate the impact on survival. Large and small RNA sequencing data were integrated and a new gene-miRNA set analysis method was developed.

Thousands of new small RNAs (miRNAs and piwi-interacting RNAs) were predicted and a 13 small RNA signature was developed to predict spread type from formalin-fixed paraffin-embedded tissues. Furthermore, integrative analyses of RNA sequencing and small RNA sequencing data revealed a global upregulation of the competing endogenous RNA network in tumor tissues of non-miliary compared to miliary spread, i.e. higher expression of circular RNAs and long non-coding RNAs compared to coding RNAs but unchanged abundance of small RNAs. This global deregulated expression pattern could be co-responsible for the spread characteristic, miliary or non-miliary, in ovarian cancer.

Ascites-derived IL-6 and IL-10 synergistically expand CD14+HLA-DR-/low myeloid-derived suppressor cells in ovarian cancer patients

Myeloid-derived suppressor cells (MDSC) play a key immunosuppressive role in various types of cancer, including ovarian cancer (OC). In this study, we characterized CD14⁺HLA-DR^–/lo MDSC with a typical monocytic phenotype (M-MDSC) in the peripheral blood (PB) and ascites from OC patients. Compared to healthy donors, OC patients had a significantly increased abundance of M-MDSC in both PB and ascites; importantly, their abundance in both compartments was inversely associated with the prognosis where OC patients with higher level of M-MDSC having a shorter relapse-free survival. Intriguingly, we demonstrated that M-MDSC could be readily induced by ascitic fluids (AF) from OC patients, which was predominantly dependent on IL-6, IL-10 and STAT3 activation as neutralization of IL-6 and/or IL-10 or inhibition of STAT3 abrogated MDSC's expansion while recombinant IL-6 and IL-10 recapitulated the expansive effect of AF; furthermore, predominantly elevated levels of IL-6 and IL-10 has been noted in the AF which was positively correlated with the abundance of M-MDSC as well as poor prognosis of OC patients. As expected, we observed that AF-driven STAT3 activation upregulated the expression of arginase (ARG1) and inducible nitric oxide synthase (iNOS) in induced M-MDSC through which these MDSC executed the immunosuppressive activity. Taken together, these results demonstrate that abundant M-MDSC are present in both periphery and ascites of OC patients whose accumulation and suppressive activity is critically attributable to ascites-derived IL-6 and IL-10 and their downstream STAT3 signal, thus providing a potentially novel therapeutic option by locally targeting MDSC to improve antitumor efficacy.

Two different, mutually exclusively distributed, TP53 mutations in ovarian and peritoneal tumor tissues of a serous ovarian cancer patient: indicative for tumor origin?

High-grade serous ovarian cancer (HGSOC) is characterized by a TP53 mutation rate of up to 96.7% and associated with a more aggressive tumor biology. The origin of HGSOC is thought to arise either from fallopian tube secretory cells or the ovarian surface epithelium/inclusion cysts, the former with more evidence. Peritoneal tumor spread is heterogeneous, either excessive in the peritoneum (with miliary appearance) or more confined to the ovaries with only few (bigger and exophytically growing) peritoneal implants. Using RNA sequencing and DNA digital droplet polymerase chain reaction (PCR), we identified two different functional TP53 mutations in one HGSOC patient: one exclusively in the ovarian tumor mass and the other exclusively in ascites tumor cells, peritoneal tumor masses, and a lymph node metastasis. In blood, both mutations could be detected, the one from the peritoneal tumors with much higher frequency, presumably because of the higher tumor load. We conclude that this mutually exclusive distribution of two different TP53 mutations in different tumor tissues indicates the development of two independent carcinomas in the peritoneal cavity, probably one originating from a precancerous lesion in the fallopian tube and the other from the ovaries. In addition, in the patient's ascites CD45 and EpCAM, double-positive cells were found-proliferating but testing negative for the above-mentioned TP53 mutations. This mutually exclusive distribution of two TP53 mutations is probably further evidence that HGSOC can originate either from the fallopian tube or (more seldom) the ovaries, the former more prone for excessive peritoneal tumor spread.

EV-Associated MMP9 in High-Grade Serous Ovarian Cancer Is Preferentially Localized to Annexin V-Binding EVs

High-grade serous ovarian cancer (HGSOC) is the most aggressive type of ovarian cancer and is responsible for most deaths caused by gynecological cancers. Numerous candidate biomarkers were identified for this disease in the last decades, but most were not sensitive or specific enough for clinical applications. Hence, new biomarkers for HGSOC are urgently required. This study aimed to identify new markers by isolating different extracellular vesicle (EV) types from the ascites of ovarian cancer patients according to their affinities for lipid-binding proteins and analyzing their protein cargo. This approach circumvents the low signal-to-noise ratio when using biological fluids for biomarker discovery and the issue of contamination by large non-EV complexes. We isolated and analyzed three distinct EV populations from the ascites of patients with ovarian cancer or cirrhosis and observed that Annexin V-binding EVs have higher levels of matrix metalloproteinase 9 in malignant compared to portal-hypertensive ascites. As this protein was not detected in other EV populations, this study validates our approach of using different EV types for optimal biomarker discovery. Furthermore, MMP9 in Annexin V-binding EVs could be a HGSOC biomarker with enhanced specificity, because its identification requires detection of two distinct components, that is, lipid and protein.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Absence of PD-L1 on tumor cells is associated with reduced MHC I expression and PD-L1 expression increases in recurrent serous ovarian cancer

Immune-evasion and immune checkpoints are promising new therapeutic targets for several cancer entities. In ovarian cancer, the clinical role of programmed cell death receptor ligand 1 (PD-L1) expression as mechanism to escape immune recognition has not been clarified yet. We analyzed PD-L1 expression of primary ovarian and peritoneal tumor tissues together with several other parameters (whole transcriptomes of isolated tumor cells, local and systemic immune cells, systemic cytokines and metabolites) and compared PD-L1 expression between primary tumor and tumor recurrences. All expressed major histocompatibility complex (MHC) I genes were negatively correlated to PD-L1 abundances on tumor tissues, indicating two mutually exclusive immune-evasion mechanisms in ovarian cancer: either down-regulation of T-cell mediated immunity by PD-L1 expression or silencing of self-antigen presentation by down-regulation of the MHC I complex. In our cohort and in most of published evidences in ovarian cancer, low PD-L1 expression is associated with unfavorable outcome. Differences in immune cell populations, cytokines, and metabolites strengthen this picture and suggest the existence of concurrent pathways for progression of this disease. Furthermore, recurrences showed significantly increased PD-L1 expression compared to the primary tumors, supporting trials of checkpoint inhibition in the recurrent setting.

Comparative transcriptome analysis links distinct peritoneal tumor spread types, miliary and non-miliary, with putative origin, tubes and ovaries, in high grade serous ovarian cancer

High grade serous ovarian cancer (HGSOC) is characterized by extensive local, i.e. peritoneal, tumor spread, manifested in two different clinical presentations, miliary (many millet sized peritoneal implants) and non-miliary (few large exophytically growing peritoneal nodes), and an overall unfavorable outcome. HGSOC is thought to arise from fallopian tube secretory epithelial cells, via so called serous tubal intraepithelial carcinomas (STICs) but an ovarian origin was never ruled out for at least some cases. Comparative transcriptome analyses of isolated tumor cells from fresh HGSOC tissues and (immortalized) ovarian surface epithelial and fallopian tube secretory epithelial cell lines revealed a close relation between putative origin and tumor spread characteristic, i.e. miliary from tubes and non-miliary from ovaries. The latter were characterized by more mesenchymal cell characteristics, more adaptive tumor immune infiltration, and a favorable overall survival. Several molecular sub-classification systems (Crijns' overall survival signature, Yoshihara's subclasses, and a collagen-remodeling signature) seem to already indicate origin. Putative origin alone is a significant independent predictor for HGSOC outcome, validated in independent patient cohorts. Characteristics of both spread types could guide development of new targeted therapeutics, which are urgently needed.

Overexpression of HE4 (human epididymis protein 4) enhances proliferation, invasion and metastasis of ovarian cancer

Overexpression of Human epididymis protein 4 (HE4) related with a role in ovarian cancer tumorigenesis while little is known about the molecular mechanism alteration by HE4 up regulation. Here we reported that overexpressed HE4 promoted ovarian cancer cells proliferation, invasion and metastasis. Furthermore, human whole genome gene expression profile microarrays revealed that 231 differentially expressed genes (DEGs) were altered in response to HE4, in which MAPK signaling, ECM receptor, cell cycle, steroid biosynthesis pathways were involved. The findings suggested that overexpressed HE4 played an important role in ovarian cancer progression and metastasis and that HE4 has the potential to serve as a novel therapeutic target for ovarian cancer.

Integrative Systemic and Local Metabolomics with Impact on Survival in High-Grade Serous Ovarian Cancer

Purpose: Cancer metabolism is characterized by alterations including aerobic glycolysis, oxidative phosphorylation, and need of fuels and building blocks.Experimental Design: Targeted metabolomics of preoperative and follow-up sera, ascites, and tumor tissues, RNA sequencing of isolated tumor cells, local and systemic chemokine, and local immune cell infiltration data from up to 65 high-grade serous ovarian cancer patients and 62 healthy controls were correlated to overall survival and integrated in a Systems Medicine manner.Results: Forty-three mainly (poly)unsaturated glycerophospholipids and four essential amino acids (citrulline) were significantly reduced in patients with short compared with long survival and healthy controls. The glycerophospholipid fingerprint is identical to the fingerprint from isolated (very) low-density lipoproteins (vLDL), indicating that the source of glycerophospholipids consumed by tumors is (v)LDL. A glycerophospholipid-score (HR, 0.46; P = 0.007) and a 100-gene signature (HR, 0.65; P = 0.004) confirmed the independent impact on survival in training (n = 65) and validation (n = 165) cohorts. High concentrations of LDLs and glycerophospholipids were independently predictors for favorable survival. Patients with low glycerophospholipids presented with more systemic inflammation (C-reactive protein and fibrinogen negatively and albumin positively correlated) but less adaptive immune cell tumor infiltration (lower tumor and immune cell PD-L1 expression), less oxygenic respiration and increased triglyceride biosynthesis in tumor cells, and lower histone expressions, correlating with higher numbers of expressed genes and more transcriptional noise, a putative neo-pluripotent tumor cell phenotype.Conclusions: Low serum phospholipids and essential amino acids are correlated with worse outcome in ovarian cancer, accompanied by a specific tumor cell phenotype. Clin Cancer Res; 23(8); 2081-92. ©2016 AACR.

Ascites modulates cancer cell behavior, contributing to tumor heterogeneity in ovarian cancer

Malignant ascites constitute a unique tumor microenvironment providing a physical structure for the accumulation of cellular and acellular components. Ascites is initiated and maintained by physical and biological factors resulting from underlying disease and forms an ecosystem that contributes to disease progression. It has been demonstrated that the cellular contents and the molecular signatures of ascites change continuously during the course of a disease. Over the past decade, increasing attention has been given to the characterization of components of ascites and their role in the progression of ovarian cancer, the most malignant gynecologic cancer in women. This review will discuss the role of ascites in disease progression, in terms of modulating cancer cell behavior and contributing to tumor heterogeneity.

Dynamic changes of tumor gene expression during repeated pressurized intraperitoneal aerosol chemotherapy (PIPAC) in women with peritoneal cancer

BACKGROUND

Intraperitoneal chemotherapy is used to treat peritoneal cancer. The pattern of gene expression changes of peritoneal cancer during intraperitoneal chemotherapy has not been studied before. Pressurized intraperitoneal aerosol chemotherapy is a new form of intraperitoneal chemotherapy using repeated applications and allowing repeated tumor sampling during chemotherapy. Here, we present the analysis of gene expression changes during pressurized intraperitoneal aerosol chemotherapy with doxorubicin and cisplatin using a 22-gene panel.

METHODS

Total RNA was extracted from 152 PC samples obtained from 63 patients in up to six cycles of intraperitoneal chemotherapy. Quantitative real-time PCR was used to determine the gene expression levels. For select genes, immunohistochemistry was used to verify gene expression changes observed on the transcript level on the protein level. Observed (changes in) expression levels were correlated with clinical outcomes.

RESULTS

Gene expression profiles differed significantly between peritoneal cancer and non- peritoneal cancer samples and between ascites-producing and non ascites-producing peritoneal cancers. Changes of gene expression patterns during repeated intraperitoneal chemotherapy cycles were prognostic of overall survival, suggesting a molecular tumor response of peritoneal cancer. Specifically, downregulation of the whole gene panel during intraperitoneal chemotherapy was associated with better treatment response and survival.

CONCLUSIONS

In summary, molecular changes of peritoneal cancer during pressurized intraperitoneal aerosol chemotherapy can be documented and may be used to refine individual treatment and prognostic estimations.

Genetic variants of lncRNA HOTAIR and risk of epithelial ovarian cancer among Chinese women

Ovarian cancer is one of the common female malignant tumors globally. However, exactly mechanism of ovarian cancer remained unknown. HOTAIR, a lncRNA in the mammalian HOXC locus, has been fully explored for its genetic variants, expression level and carcinogenesis, development and progression of multiple cancers, except for ovarian cancer. In this study, we hypothesized that abnormal expression of HOTAIR and common variants of HOTAIR are associated with risk of Epithelial ovarian cancer (EOC). We first evaluated the HOTAIR levels in 100 paired tissues of EOC patients and corresponding normal tissues. Results showed that the expression level of HOTAIR in EOC tissues was significantly higher than that in corresponding normal tissues. Then the genotyping analyses of HOTAIR gene was conducted in a Chinese population. The results indicated that rs4759314 and rs7958904 were significantly associated with EOC susceptibility. For rs4759314, the difference between the G allele (as the reference) and the A allele was statistically significant (adjusted OR, 1.34; 95% CI: 1.08–1.65; P = 6.8 × 10⁻³). For rs7958904, C allele was associated a significantly decreased EOC risk when compared with G allele (OR: 0.77; 95% CI: 0.67–0.89; P = 4.2 × 10⁻⁴). The study identified that HOTAIR variants could be a useful biomarker for the predisposition to EOC and for the early diagnosis of the disease.

Novel high-grade serous epithelial ovarian cancer cell lines that reflect the molecular diversity of both the sporadic and hereditary disease

Few cell line models of epithelial ovarian cancer (EOC) have been developed for the high-grade serous (HGS) subtype, which is the most common and lethal form of gynaecological cancer. Here we describe the establishment of six new EOC cell lines spontaneously derived from HGS tumors (TOV2978G, TOV3041G and TOV3291G) or ascites (OV866(2), OV4453 and OV4485). Exome sequencing revealed somatic TP53 mutations in five of the cell lines. One cell line has a novel BRCA1 splice-site mutation, and another, a recurrent BRCA2 nonsense mutation, both of germline origin. The novel BRCA1 mutation induced abnormal splicing, mRNA instability, resulting in the absence of BRCA1 protein. None of the cell lines harbor mutations in KRAS or BRAF, which are characteristic of other EOC subtypes. SNP arrays showed that all of the cell lines exhibited structural chromosomal abnormalities, copy number alterations and regions of loss of heterozygosity, consistent with those described for HGS. Four cell lines were able to produce 3D-spheroids, two exhibited anchorage-independent growth, and three (including the BRCA1 and BRCA2 mutated cell lines) formed tumors in SCID mice. These novel HGS EOC cell lines and their detailed characterization provide new research tools for investigating the most common and lethal form of EOC.