Meeting the challenge of ascites in ovarian cancer: new avenues for therapy and research

Evaluation of the potential of a new ribavirin analog impairing the dissemination of ovarian cancer cells

Epithelial ovarian cancers are insidious pathologies that give a poor prognosis due to their late discovery and the increasing emergence of chemoresistance. Development of small pharmacological anticancer molecules remains a major challenge. Ribavirin, usually used in the treatment of hepatitis C virus infections and more recently few cancers, has been a suggestion. However, Ribavirin has many side-effects, suggesting that the synthesis of analogs might be more appropriate. We have investigated the effect of a Ribavirin analog, SRO-91, on cancer cell behavioral characteristics considered as some of the hallmarks of cancer. Two human ovarian adenocarcinoma cell lines (SKOV3 and IGROV1) and normal cells (mesothelial and fibroblasts) have been used to compare the effects of SRO-91 with those of Ribavirin on cell behavior underlying tumor cell dissemination. SRO-91, like Ribavirin, inhibits proliferation, migration, clonogenicity and spheroids formation of cancer cells. Unlike Ribavirin, SRO-91 is preferentially toxic to cancer compared with normal cells. An in vitro physiologically relevant model showed that SRO-91, like Ribavirin or cisplatin, inhibits cancer cell implantation onto peritoneal mesothelium. In conclusion, SRO-91 analog effects on tumor dissemination and its safety regarding non-cancerous (normal) cells are encouraging findings a promising drug for the treatment of ovarian cancer.

Ovarian Cancer Dissemination-A Cell Biologist's Perspective

Epithelial ovarian cancer (EOC) comprises multiple disease states representing a variety of distinct tumors that, irrespective of tissue of origin, genetic aberrations and pathological features, share common patterns of dissemination to the peritoneal cavity. EOC peritoneal dissemination is a stepwise process that includes the formation of malignant outgrowths that detach and establish widespread peritoneal metastases through adhesion to serosal membranes. The cell biology associated with outgrowth formation, detachment, and de novo adhesion is at the nexus of diverse genetic backgrounds that characterize the disease. Development of treatment for metastatic disease will require detailed characterization of cellular processes involved in each step of EOC peritoneal dissemination. This article offers a review of the literature that relates to the current stage of knowledge about distinct steps of EOC peritoneal dissemination, with emphasis on the cell biology aspects of the process.

Targeted activation of Stat3 in combination with paclitaxel results in increased apoptosis in epithelial ovarian cancer cells and a reduced tumour burden

Objectives

Stat3 is persistently activated in ovarian cancer cells, with a crucial role in tumour onset and progression. In this study, we examined the anti‐tumour effect of a small‐molecule inhibitor napabucasin (BBI608) on epithelial ovarian cancer (EOC) in vitro and in vivo, and investigated the underlying molecular mechanism of this drug in combination with paclitaxel.

Materials and Methods

A total of 156 ovarian cancer patient samples were analysed to determine the correlation between pStat3 expression in tumour cells and the prognosis of EOC patients. The anti‐tumour effect of BBI608 and/or paclitaxel on ovarian cancer in vitro was evaluated by CCK‐8, flow cytometry, Western blot and transwell assays. An in vivo intraperitoneal model was performed to confirm the effect of BBI608 on pStat3‐mediated peritoneal metastasis when combined with paclitaxel.

Results

Patients with high expression of pStat3 had poorer overall survival and progression‐free survival than those with low pStat3 expression. The synergy of BBI608 in combination with paclitaxel exerted dramatic growth inhibition and induced apoptosis in EOC cell lines. In vivo, the combination of two drugs significantly decreased intraperitoneal tumour burden and ascites volume, prolonged survival of tumour‐bearing mice compared with each monotherapy; these results were associated with downregulation of phospho‐Stat3 and activation of apoptosis pathway.

Conclusions

Targeting the activation of Stat3 may be a potential therapeutic approach for EOC by acting synergistically with paclitaxel.

Repurposing Pan-HDAC Inhibitors for ARID1A-Mutated Ovarian Cancer

ARID1A , a subunit of the SWI/SNF complex, is among the most frequently mutated genes across cancer types. ARID1A is mutated in more than 50% of ovarian clear cell carcinomas (OCCCs), diseases that have no effective therapy. Here, we show that ARID1A mutation confers sensitivity to pan-HDAC inhibitors such as SAHA in ovarian cancers. This correlated with enhanced growth suppression induced by the inhibition of HDAC2 activity in ARID1A-mutated cells. HDAC2 interacts with EZH2 in an ARID1A status-dependent manner. HDAC2 functions as a co-repressor of EZH2 to suppress the expression of EZH2/ARID1A target tumor suppressor genes such as PIK3IP1 to inhibit proliferation and promote apoptosis. SAHA reduced the growth and ascites of the ARID1A-inactivated OCCCs in both orthotopic and genetic mouse models. This correlated with a significant improvement of survival of mice bearing ARID1A-mutated OCCCs. These findings provided preclinical rationales for repurposing FDA-approved pan-HDAC inhibitors for treating ARID1A-mutated cancers.

Tumor-Associated Macrophages (TAMs): A Critical Activator In Ovarian Cancer Metastasis

Tumor-associated macrophages (TAMs) that appear in every stage of cancer progression are usually tumor-promoting cells and are present abundantly in the tumor-associated microenvironment. In ovarian cancer, the overall and intratumoral M1/M2 ratio is a relatively efficient TAM parameter for predicting the prognosis of patients, especially for serous tissue type cancer. TAMs exhibit immunological checkpoint modulators, such as the B7 family and programmed death-ligand 1 (PD-L1), and play a key role in the development, metastasis and invasion of ovarian cancer, but the underlying mechanism is barely understood. Ovarian cancer is a severe gynecological malignancy with high mortality. Ovarian cancer-associated death can primarily be attributed to cancer metastasis. The majority of patients are diagnosed with wide dissemination in the peritoneum and omentum, limiting the effectiveness of surgery and chemotherapy. In addition, unlike other well-documented cancers, metastasis through vasculature is not a usual dissemination pathway in ovarian cancer. This review sheds light on TAMs and the main process and mechanism of ovarian cancer metastasis.

Ovarian Cancer: Differentially Expressed microRNAs in Tumor Tissue and Cell-Free Ascitic Fluid as Potential Novel Biomarkers

Ovarian cancer is the deadliest gynecologic cancer. The large-scale microRNA (miRNA) expression profiling and individual miRNA validation was performed to find potential novel biomarkers for ovarian cancer. The most consistent overexpression of miRs-200b-3p, 135 b-5p and 182-5p was found in both ascitic fluid and tumors and suggests their potential as oncogenes. miR-451a was consistently underexpressed so may be a tumor suppressor. Results were inconsistent for miR-204-5p, which was overexpressed in ascitic fluid but underexpressed in tumor tissue. miR-203a-3p was generally overexpressed but this failed to be proved in independent sample set in tissue validation.

Diverse Effects of Lysophosphatidic Acid Receptors on Ovarian Cancer Signaling Pathways

Lysophosphatidic acid (LPA) is a bioactive phospholipid with mitogenic and growth factor-like activities affecting cell invasion, cancer progression, and resistance. It is produced mainly by autotaxin and acts on six G-protein-coupled receptors, LPAR1-6. LPA has recently been implicated as a growth factor present in ascites of ovarian cancer patients. However, mitogenic pathways stimulated by LPA via its receptors may involve any novel, thus far uncharacterized, signaling pathway(s). Here we show that three LPA receptors are involved in tumor progression by activation of both the AKT and ERK signaling pathways. CRISPR-edited LPAR2 and LPAR3 knockouts have opposing effects on ERK activation, whereas LPAR6 is involved in the activation of AKT, affecting cell migration and invasion. Our study identifies specific molecular machinery triggered by LPA and its receptors that modulates tumor cells and can serve as therapeutic target in this malignancy.

Nanotechnology and Immunotherapy in Ovarian Cancer: Tracing New Landscapes

Ovarian cancer (OC) is the seventh most common cancer in women worldwide. Standard therapeutic treatments involve debulking surgery combined with platinum-based chemotherapies. Of the patients with advanced-stage cancer who initially respond to current treatments, 50%-75% relapse. Immunotherapy-based approaches aimed at boosting antitumor immunity have recently emerged as promising tools to challenge tumor progression. Treatments with inhibitors of immune checkpoint molecules have shown impressive results in other types of tumors. However, only 15% of checkpoint inhibitors evaluated have proven successful in OC due to the immunosuppressive environment of the tumor and the transport barriers. This limits the efficacy of the existing immunotherapies. Nanotechnology-based delivery systems hold the potential to overcome such limitations. Various nanoformulations including polymeric, liposomes, and lipid-polymer hybrid nanoparticles have already been proposed to improve the biodistribution and targeting capabilities of drugs against tumor-associated immune cells, including dendritic cells and macrophages. In this review, we examine the impact of immunotherapeutic approaches that are currently under consideration for the treatment of OC. In this review, we also provide a comprehensive analysis of the existing nanoparticle-based synthetic strategies and their limitations and advantages over standard treatments. Furthermore, we discuss how the strength of the combination of nanotechnology with immunotherapy may help to overcome the current therapeutic limitations associated with their individual application and unravel a new paradigm in the treatment of this malignancy.

Dual-platform affinity proteomics identifies links between the recurrence of ovarian carcinoma and proteins released into the tumor microenvironment

The peritoneal fluid (ascites), replete with abundant tumor-promoting factors and extracellular vesicles (EVs) reflecting the tumor secretome, plays an essential role in ovarian high-grade serous carcinoma (HGSC) metastasis and immune suppression. A comprehensive picture of mediators impacting HGSC progression is, however, not available.

Methods: Proteins in ascites from HGSC patients were quantified by the aptamer-based SOMAscan affinity proteomic platform. SOMAscan data were analyzed by bioinformatic methods to reveal clinically relevant links and functional connections, and were validated using the antibody-based proximity extension assay (PEA) Olink platform. Mass spectrometry was used to identify proteins in extracellular microvesicles released by HGSC cells.

Results: Consistent with the clinical features of HGSC, 779 proteins in ascites identified by SOMAscan clustered into groups associated either with metastasis and a short relapse-free survival (RFS), or with immune regulation and a favorable RFS. In total, 346 proteins were linked to OC recurrence in either direction. Reanalysis of 214 of these proteins by PEA revealed an excellent median Spearman inter-platform correlation of ρ=0.82 for the 46 positively RFS-associated proteins in both datasets. Intriguingly, many proteins strongly associated with clinical outcome were constituents of extracellular vesicles. These include proteins either linked to a poor RFS, such as HSPA1A, BCAM and DKK1, or associated with a favorable outcome, such as the protein kinase LCK. Finally, based on these data we defined two protein signatures that clearly classify short-term and long-term relapse-free survivors.

Conclusion: The ascites secretome points to metastasis-promoting events and an anti-tumor response as the major determinants of the clinical outcome of HGSC. Relevant proteins include both bone fide secreted and vesicle-encapsulated polypeptides, many of which have previously not been linked to HGSC recurrence. Besides a deeper understanding of the HGSC microenvironment our data provide novel potential tools for HGSC patient stratification. Furthermore, the first large-scale inter-platform validation of SOMAscan and PEA will be invaluable for other studies using these affinity proteomics platforms.

In vivo selection reveals autophagy promotes adaptation of metastatic ovarian cancer cells to abdominal microenvironment

Peritoneal dissemination is the most frequent metastatic route of ovarian cancer. However, due to the high heterogeneity in ovarian cancer, most conventional studies lack parental tumor controls relevant to metastases and, thus, it is difficult to trace the molecular changes of cancer cells along with the selection by the abdominal microenvironment. Here, we established an in vivo mouse peritoneal dissemination scheme that allowed us to select more aggressive sublines from parental ovarian cancer cells, including A2780 and SKOV-3. Microarray and gene profiling analyses indicated that autophagy-related genes were enriched in selected malignant sublines. Detection of LC3-II, p62 and autophagic puncta demonstrated that these malignant variants were more sensitive to autophagic induction when exposed to diverse stress conditions, such as high cell density, starvation and drug treatment. As compared with parental A2780, the selected variant acquired the ability to grow better under high-density stress; however, this effect was reversed by addition of autophagic inhibitors or knockdown of ATG5. When analyzing the clinical profiles of autophagy-related genes identified to be enriched in malignant A2780 variant, 73% of them had prognostic significance for the survival of ovarian cancer patients. Taken together, our findings indicate that an increase in autophagic potency among ovarian cancer cells is crucial for selection of metastatic colonies in the abdominal microenvironment. In addition, the derived autophagic gene profile can not only predict prognosis well but can also be potentially applied to precision medicine for identifying those ovarian cancer patients suitable for taking anti-autophagy cancer drugs.

Role of the Exosome in Ovarian Cancer Progression and Its Potential as a Therapeutic Target

Peritoneal dissemination is a distinct form of metastasis in ovarian cancer that precedes hematogenic or lymphatic metastasis. Exosomes are extracellular vesicles of 30–150 nm in diameter secreted by different cell types and internalized by target cells. There is emerging evidence that exosomes facilitate the peritoneal dissemination of ovarian cancer by mediating intercellular communication between cancer cells and the tumor microenvironment through the transfer of nucleic acids, proteins, and lipids. Furthermore, therapeutic applications of exosomes as drug cargo delivery are attracting research interest because exosomes are stabilized in circulation. This review highlights the functions of exosomes in each process of the peritoneal dissemination of ovarian cancer and discusses their potential for cancer therapeutics.

Inhibition LC3B can increase chemosensitivity of ovarian cancer cells

Background

Ovarian cancer is often accompanied by the production of ascites, and patients with repeated ascites are associated with chemotherapy resistance. The previous study confirmed that the ovarian cancer patients who developed ascites after chemotherapy had elevated autophagy levels in the ascites and precipitated cells, which was positively correlated with MDR1 expression in the blood of patients.

Methods

In order to explore the correlation between autophagy and chemoresistant, we searched TCGA and GEO database to analyze the correlation between LC3B and MDR1, and identified the targeting miRNA of LC3B. It was verified by dual luciferase that miR-204 can target LC3B. The ovarian cancer cell line and the BALB/c nude mice tumor-bearing model were selected for in vitro and in vivo verification. In vitro studies confirmed that ovarian cancer cells were more sensitive to cisplatin by inhibiting LC3B.

Results

Overexpression of miR-204 reduced the expression of LC3B, Atg7, and MDR1, and promoted apoptosis. In vivo studies have also confirmed that reducing the level of autophagy in ovarian cancer cells increases the sensitivity to cisplatin.

Conclusions

It suggests that miR-204 can be used as a tumor suppressor gene and LC3B expression level can be used as a potential molecular marker to guide the diagnosis and treatment of patients with ovarian cancer.

Ovarian cancer stem cells and macrophages reciprocally interact through the WNT pathway to promote pro-tumoral and malignant phenotypes in 3D engineered microenvironments

BACKGROUND

Innate immune cells such as macrophages are abundantly present within malignant ascites, where they share the microenvironment with ovarian cancer stem cells (CSC).

METHODS

To mimic this malignant ascites microenvironment, we created a hanging-drop hetero-spheroid model to bring CSCs and macrophages in close association. Within these hetero-spheroids, CD68+ macrophages (derived from U937 or peripheral blood monocytes) make up ~ 20% of the population, while the rest are ovarian cancer cells and ovarian cancer stem cells (derived from the high grade serous ovarian cancer cell line, OVCAR3).

RESULTS

Our results indicate that CSCs drive the upregulation of M2 macrophage marker CD206 within hetero-spheroids, compared to bulk ovarian cancer cells, implying an inherently more immuno-suppressive program. Moreover, an increased maintenance of elevated aldehyde dehydrogenase (ALDH) activity is noted within hetero-spheroids that include pre-polarized CD206+ M2 macrophages, implying a reciprocal interaction that drives pro-tumoral activation as well as CSC self-renewal. Consistent with enriched CSCs, we also observe increased levels of pro-tumoral IL-10 and IL-6 cytokines in the CSC/M2-macrophage hetero-spheroids. CSC/M2-macrophage hetero-spheroids are also less sensitive to the chemotherapeutic agent carboplatin and are subsequently more invasive in transwell assays. Using inhibitors of WNT secretion in both CSCs and macrophages, we found that CSC-derived WNT ligands drove CD206+ M2 macrophage activation, and that, conversely, macrophage-derived WNT ligands enriched ALDH+ cells within the CSC compartment of hetero-spheroids. Upon examination of specific WNT ligand expression within the monocyte-derived macrophage system, we observed a significant elevation in gene expression for WNT5B. In CSCs co-cultured with macrophages within hetero-spheroids, increases in several WNT ligands were observed, and this increase was significantly inhibited when WNT5B was knocked down in macrophages.

CONCLUSIONS

Our data implies that macrophage- initiated WNT signaling could play a significant role in the maintenance of stemness, and the resulting phenotypes of chemoresistance and invasiveness. Our results indicate paracrine WNT activation during CSC/M2 macrophages interaction constitutes a positive feedback loop that likely contributes to the more aggressive phenotype, which makes the WNT pathway a potential target to reduce the CSC and M2 macrophage compartments in the tumor microenvironment.

The Role of Cancer Stem Cells and Mechanical Forces in Ovarian Cancer Metastasis

Ovarian cancer is an extremely lethal gynecologic disease; with the high-grade serous subtype predominantly associated with poor survival rates. Lack of early diagnostic biomarkers and prevalence of post-treatment recurrence, present substantial challenges in treating ovarian cancers. These cancers are also characterized by a high degree of heterogeneity and protracted metastasis, further complicating treatment. Within the ovarian tumor microenvironment, cancer stem-like cells and mechanical stimuli are two underappreciated key elements that play a crucial role in facilitating these outcomes. In this review article, we highlight their roles in modulating ovarian cancer metastasis. Specifically, we outline the clinical relevance of cancer stem-like cells, and challenges associated with their identification and characterization and summarize the ways in which they modulate ovarian cancer metastasis. Further, we review the mechanical cues in the ovarian tumor microenvironment, including, tension, shear, compression and matrix stiffness, that influence (cancer stem-like cells and) metastasis in ovarian cancers. Lastly, we outline the challenges associated with probing these important modulators of ovarian cancer metastasis and provide suggestions for incorporating these cues in basic biology and translational research focused on metastasis. We conclude that future studies on ovarian cancer metastasis will benefit from the careful consideration of mechanical stimuli and cancer stem cells, ultimately allowing for the development of more effective therapies.

Enhanced anti-tumor efficacy and safety with metronomic intraperitoneal chemotherapy for metastatic ovarian cancer using biodegradable nanotextile implants

The objective of this study was to evaluate intraperitoneal (IP) metronomic chemotherapy using sustained release paclitaxel (PTX) delivery from electrospun biodegradable polymeric yarns woven into suturable nanotextiles. Following confirmation of in vitro PTX efficacy in ID8-VEGF epithelial ovarian cancer cells, in vivo studies were performed upon surgical peritoneal implantation of nanotextile implants in orthotopic, syngeneic ID8-VEGF tumor-bearing C57BL/6 mice. In comparison to the clinical PTX-solution, there was a significant enhancement of anti-tumor efficacy and safety with PTX-nanotextiles. After 35-days, the peritoneum of tumor-bearing mice with PTX-nanotextiles was completely devoid of tumor nodules and ascitic fluid. Additionally, VEGF levels measured in peritoneal lavage fluid were 300-fold lower compared to PTX-solution and 600-fold lower as compared to untreated tumor-bearing animals. PTX-solution treated group also developed severe metastatic lesions and progressive ascitic fluid buildup. More importantly, no signs of systemic/ organ toxicity were observed in PTX-nanotextile implanted mice, unlike the systemic toxic effects induced by PTX-solution. Collectively, our results show the therapeutic and safety advantages offered by combining clinically translatable metronomic low-dose chemotherapy and IP pharmacokinetics using biodegradable nanotextile implants in addressing the challenges of late-stage ovarian cancer.

MicroRNA-654-5p suppresses ovarian cancer development impacting on MYC, WNT and AKT pathways

Ovarian cancer is the most lethal gynecological malignancy due to the silent nature on its early onset and the rapid acquisition of drug resistance. Histologically heterogeneous, it includes several subtypes with different mutational landscapes, hampering the development of effective targeted therapies. Non-coding RNAs are emerging as potential new therapeutic targets in cancer. To search for a microRNA signature related to ovarian carcinomas and study its potential as effective targeted therapy, we examined the expression of 768 miRNA in a large collection of tumor samples and found miR-654-5p to be infraexpressed in ovarian serous carcinomas, the most common and aggressive type. Restoration of miR-654-5p levels reduced tumor cell viability in vitro and in vivo and impaired sphere formation capacity and viability of ovarian cancer patient-derived ascitic cells ex vivo. CDCP1 and PLAGL2 oncogenes were found to be the most relevant direct miR-654-5p targets and both genes convey in a molecular signature associated with key cancer pathways relevant to ovarian tumorigenesis, such as MYC, WNT and AKT pathways. Together, we unveiled the tumor suppressor function of miR-654-5p, suggesting that its restoration or co-targeting of CDCP1 and PLAGL2 may be an effective therapeutic approach for ovarian cancer.

Ovarian Cancer Stem Cells: Role in Metastasis and Opportunity for Therapeutic Targeting

Ovarian cancer (OC) is a heterogeneous disease usually diagnosed at a late stage. Cancer stem cells (CSCs) that exist within the bulk tumor survive first-line chemotherapy and contribute to resistant disease with metastasis. Understanding the key features of CSC biology provides valuable opportunities to develop OCSC-directed therapeutics, which will eventually improve the clinical outcomes of patients. Although significant developments have occurred since OCSCs were first described, the involvement of CSCs in ovarian tumor metastasis is not fully understood. Here, we discuss putative CSC markers and the fundamental role of CSCs in facilitating tumor dissemination in OC. Additionally, we focus on promising CSC-targeting strategies in preclinical and clinical studies of OC and discuss potential challenges in CSC research.

Effects of dynein light chain Tctex-type 3 on the biological behavior of ovarian cancer

OBJECTIVE

To investigate dynein light chain Tctex-type 3 (DYNLT3) protein expression in ovarian epithelial lesions and explore the effects and related mechanisms of DYNLT3 in terms of the biological behavior of ovarian cancer.

MATERIALS AND METHODS

Initially, expression of the DYNLT3 protein in ovarian epithelial lesions was detected by immunohistochemical staining, and the prognostic value of DYNLT3 mRNA expression in ovarian cancer patients was assessed using the Kaplan-Meier plotter database. Then, the mRNA and protein expression of DYNLT3 in IOSE80 normal ovarian epithelial cells and SKOV3 ovarian cancer cells was evaluated by quantitative real-time polymerase chain reaction and Western blotting respectively, and the proliferation, apoptosis, migration and invasion of SKOV3 cells after DYNLT3 over-expression and under-expression were investigated by CCK-8 assays and immunofluorescence staining, flow cytometry, wound healing assays and Transwell invasion assays, respectively. Furthermore, the expression of the proliferation-related proteins PCNA and Ki-67 and the invasion- and migration-related proteins Ezrin, Fascin, MMP2 and MMP9 in cells was examined by Western blotting.

RESULTS

The protein expression of DYNLT3 gradually increased during the progression of ovarian epithelial lesions, and was related to the development of ovarian cancer. High expression of DYNLT3 mRNA was related to poor overall survival and progression free survival, especially in serous ovarian cancer patients. In addition, overexpression of DYNLT3 promoted SKOV3 cell proliferation, invasion and migration. The corresponding results were also verified by a DYNLT3 knockdown assay. Moreover, DYNLT3 increased cell proliferation, which was related to Ki-67 expression. Besides, DYNLT3 enhanced cell invasion and migration through regulating Ezrin, but not Fascin, MMP2 or MMP9.

CONCLUSION

DYNLT3 exerts pro-tumoral effects on ovarian cancer through promoting cell proliferation, migration and invasion, possibly via regulating the protein expression of Ki-67 and Ezrin. DYNLT3 may be a potential prognostic predictor in ovarian cancer.

Prognostic impact of intraoperative peritoneal cytology in interval debulking surgery for pelvic high-grade serous carcinoma

Background and Objectives

The aim of this study was to determine whether peritoneal washing cytology (PWC) during interval debulking surgery (IDS) could predict the prognosis of patients with pelvic high‐grade serous carcinoma (HGSC) achieving R0 status.

Methods

Between January 2007 and May 2018, 110 patients with ovarian/tubal/primary peritoneal HGSC received platinum‐based neo‐adjuvant chemotherapy, followed by IDS at National Cancer Center Hospital, Japan. All the patients achieved R0 debulking status, defined as no macroscopic residual tumor in the peritoneal cavity at the completion of IDS. PWC was performed before debulking during IDS. The survival outcomes were compared between the PWC‐positive and PWC‐negative groups.

Results

The median progression free survival (PFS) for the entire cohort was 17 months (range, 5‐133 months). The median PFS for the PWC‐positive group was significantly shorter than that of the PWC‐negative group (16 vs 19 months, HR 2.04, 95% CI 1.22‐3.41, P‐value < 0.01). Increased risk of progression was observed on both univariate and multivariate analyses, including age and FIGO stage (HR 2.28; 95% CI 1.35‐3.84, P < 0.01).

Conclusions

The positive PWC during IDS was found to predict earlier disease recurrence in patients with pelvic HGSC achieving R0 status. As performing PWC during IDS becomes standard practice, prospective validation should be conducted in the future.

High-throughput assessment of the antibody profile in ovarian cancer ascitic fluids

The identification of effective biomarkers for early diagnosis, prognosis, and response to treatments remains a challenge in ovarian cancer (OC) research. Here, we present an unbiased high-throughput approach to profile ascitic fluid autoantibodies in order to obtain a tumor-specific antigen signature in OC. We first reported the reactivity of immunoglobulins (Igs) purified from OC patient ascites towards two different OC cell lines. Using a discovery set of Igs, we selected tumor-specific antigens from a phage display cDNA library. After biopanning, 700 proteins were expressed as fusion protein and used in protein array to enable large-scale immunoscreening with independent sets of cancer and noncancerous control. Finally, the selected antigens were validated by ELISA. The initial screening identified eight antigenic clones: CREB3, MRPL46, EXOSC10, BCOR, HMGN2, HIP1R, OLFM4, and KIAA1755. These antigens were all validated by ELISA in a study involving ascitic Igs from 153 patients (69 with OC, 34 with other cancers and 50 without cancer), with CREB3 showing the highest sensitivity (86.95%) and specificity (98%). Notably, we were able to identify an association between the tumor-associated (TA) antibody response and the response to a first-line tumor treatment (platinum-based chemotherapy). A stronger association was found by combining three antigens (BCOR, CREB3, and MRLP46) as a single antibody signature. Measurement of an ascitic fluid antibody response to multiple TA antigens may aid in the identification of new prognostic signatures in OC patients and shift attention to new potentially relevant targets.

Sialyl Lewisx-P-selectin cascade mediates tumor-mesothelial adhesion in ascitic fluid shear flow

Organ-specific colonization suggests that specific cell–cell recognition is essential. Yet, very little is known about this particular interaction. Moreover, tumor cell lodgement requires binding under shear stress, but not static, conditions. Here, we successfully isolate the metastatic populations of cancer stem/tumor-initiating cells (M-CSCs). We show that the M-CSCs tether more and roll slower than the non-metastatic (NM)-CSCs, thus resulting in the preferential binding to the peritoneal mesothelium under ascitic fluid shear stress. Mechanistically, this interaction is mediated by P-selectin expressed by the peritoneal mesothelium. Insulin-like growth factor receptor-1 carrying an uncommon non-sulfated sialyl-Lewis^x (sLe^x) epitope serves as a distinct P-selectin binding determinant. Several glycosyltransferases, particularly α1,3-fucosyltransferase with rate-limiting activity for sLe^x synthesis, are highly expressed in M-CSCs. Tumor xenografts and clinical samples corroborate the relevance of these findings. These data advance our understanding on the molecular regulation of peritoneal metastasis and support the therapeutic potential of targeting the sLe^x-P-selectin cascade.

Tumor cell in the peritoneum are often exposed to shear forces generated by ascitic flow during metastasis. Here, the authors show that metastatic cancer stem cells tether more and roll slower than the non-metastatic counterparts, and that sialyl-Lewis^x -P-selectin axis mediates peritoneal metastasis.

An omentum-inspired 3D PEG hydrogel for identifying ECM-drivers of drug resistant ovarian cancer

Ovarian cancer (OvCa) is a challenging disease to treat due to poor screening techniques and late diagnosis. There is an urgent need for additional therapy options, as patients recur in 70% of cases. The limited availability of clinical treatment options could be a result of poor predictions in early stage drug screens on standard tissue culture polystyrene (TCPS). TCPS does not capture the mechanical and biochemical cues that cells experience in vivo, which can impact how cells will respond to a drug. Therefore, an in vitro model that captures some of the microenvironment features that the cells experience in vivo could provide better insights into drug responses. In this study, we formed 3D multicellular tumor spheroids (MCTS) in microwells and encapsulated them in 3D omentum-inspired hydrogels. SKOV-3 MCTS were resistant to Paclitaxel in our 3D hydrogels compared to a monolayer on TCPS. Toward clinical application, we tested cells from patients [ovarian carcinoma ascites spheroids (OCAS)] who had been treated with Paclitaxel, and drug responses predicted by using the 3D omentum-inspired hydrogels demonstrated the lack of the Paclitaxel response of these samples. Additionally, we observed the presence of collagen production around the encapsulated SKOV-3 MCTS, but not significantly on TCPS. Our results demonstrated that our 3D omentum-inspired hydrogel is an improved in vitro drug testing platform to study the OvCa drug response for patient-derived cells and helped us identify collagen 3 as a potential driver of Paclitaxel resistance in 3D.

Nanoformulation of Talazoparib Delays Tumor Progression and Ascites Formation in a Late Stage Cancer Model

Talazoparib, a potent PARP inhibitor, induces synthetic lethality in BRCA-deficient cancers making it an attractive candidate for ovarian cancer treatment. However, its potency lends itself to side effects associated more closely with traditional chemotherapeutics than other clinically approved PARP inhbitors. We sought to formulate Talazoparib in a nanoparticle delivery system, which allows the drug to be administered intraperitoneally. This was done to specifically target peritoneal dissemination of late stage metastatic ovarian cancer and increase talazoparib's therapeutic efficacy while minimizing toxic side effects. NanoTalazoparib was developed and characterized with regard to its size, loading, and surface charge. Talazoparib and NanoTalazoparib were tested on a panel of murine and human BRCA cell lines and the dose response was compared to Olaparib's, the currently used PARP inhibitor. Therapeutic efficacy was tested in vivo in a Brca peritoneal cancer model that mimics late stage disseminated disease. NanoTalazoparib has a diameter of about 70 nm with a neutral surface charge and ~75% encapsulation efficiency, which slowly releases the drug over several hours. Dose response analysis indicated that the murine cell lines with conditional BRCA1/2, PTEN, and TP53 deletions had the lowest IC50s. NanoTalazoparib administered on a schedule of three doses weekly slowed disease progression and resulted in significantly less mice with ascites at the end point compared to controls. These results indicate that the slow release nanoformulation, NanoTalazoparib, effectively delivers PARP inhibitor therapy to the peritoneal cavity for disseminated cancer treatment. The ability to decrease ascites formation with the introduction of intraperitoneal NanoTalazoparib suggests this treatment may be an effective way to treat ovarian cancer-associated ascites and slow disease progression.

Dihydrofolate reductase as a predictor for poor response to platinum-based chemotherapy in epithelial ovarian cancer

BACKGROUND

Platinum-based chemotherapy is the first line chemotherapy regimen for ovarian cancer patients. However, chemotherapy resistance is observed in a large proportion of patients. It is urgently needed to investigate prognostic biomarkers for chemo-sensitivity in ovarian cancer.

METHODS

Dihydrofolate reductase (DHFR) expression was measured by immunohistochemical staining in 108 specimens, as well as DHFR mRNA variants with qRT-PCR assays. The correlation between DHFR expression and platinum-based chemotherapy response was analyzed. The prognostic significance of DHFR expression was evaluated in ovarian cancer.

RESULTS

Positive DHFR expression was observed in 48 specimens, which was correlated to chemotherapy resistance in ovarian cancer patients. Elevated DHFR2 mRNA expression, rather than DHFR1, was observed in chemotherapy resistant tumors. Positive DHFR expression was correlated with higher histologic grade in ovarian cancer (P = 0.014). Kaplan-Meier analysis indicated that DHFR positive expression predicted poor disease-free survival (DFS) (P = 0.040), but not overall survival (OS) of ovarian cancer patients (P = 0.706). The prognostic value was further supported by TCGA data analysis. Cox regression analysis indicated that positive DHFR expression was an independent detrimental factor for disease progression for ovarian cancer patients (P = 0.016).

CONCLUSION

DHFR level measurement was a valuable prognostic biomarker for chemo-sensitivity of ovarian cancer. Molecular analysis for DHFR variants will provide important evidence for chemotherapy regimen options.

Neoantigens retention in patient derived xenograft models mediates autologous T cells activation in ovarian cancer

Ovarian cancer (OC) has an overall modest number of mutations that facilitate a functional immune infiltrate able to recognize tumor mutated antigens, or neoantigens. Although patient-derived xenografts (PDXs) can partially model the tumor mutational load and mimic response to chemotherapy, no study profiled a neoantigen-driven response in OC PDXs. Here we demonstrate that the genomic status of the primary tumor from an OC patient can be recapitulated in vivo in a PDX model, with the goal of defining autologous T cells activation by neoantigens using in silico, in vitro and in vivo approaches. By profiling the PDX mutanome we discovered three main clusters of mutations defining the expansion, retraction or conservation of tumor clones based on their variant allele frequencies (VAF). RNASeq analyses revealed a strong functional conservation between the primary tumor and PDXs, highlighted by the upregulation of antigen presenting pathways. We tested in vitro a set of 30 neoantigens for recognition by autologous T cells and identified a core of six neoantigens that define a potent T cell activation able to slow tumor growth in vivo. The pattern of recognition of these six neoantigens indicates the pre-existence of anti-tumor immunity in the patient. To evaluate the breadth of T cell activation, we performed single cell sequencing profiling the TCR repertoire upon stimulation with neoantigenic moieties and identified sequence motifs that define an oligoclonal and autologous T cell response. Overall, these results indicate that OC PDXs can be a valid tool to model OC response to immunotherapy.

Photoacoustic Flow System for the Detection of Ovarian Circulating Tumor Cells Utilizing Copper Sulfide Nanoparticles

The development of cell-specific photoacoustic (PA) contrast agents within systems of fluidic flow provides opportunities for the accurate detection of early stage cancer metastasis. Despite the promise of exogenous contrast agents for use in clinical settings, applications are currently limited by both material biocompatibility and target specificity. In this study, folic acid functionalized copper sulfide nanoparticles (FA-CuS NPs) are synthesized to enable ovarian-cancer-specific binding and PA detection in a custom flow system. Folate receptors, known to be overexpressed on the surface of ovarian cancer cells, have remained an ideal candidate for specific targeting through functionalization on nanoparticles and other contrast agents. In combination with copper sulfide nanoparticles' strong absorbance in the near-infrared (NIR), these FA-CuS NPs are an ideal contrast agent capable of being detected by photoacoustic flow cytometry. For the first time, this study shows a potential PA contrast agent to accurately identify ovarian circulating tumor cells in flow.

Patients' perspectives towards malignant ascites: results of a prospective observational trial regarding expectations, characteristics and quality of life-a study of the North-Eastern-German Society of Gynecological Oncology

PURPOSE

Malignant ascites (MA) is a frequent and common symptom in (gyneco-) oncological patients. The present trial evaluated and assessed patients' characteristics, clinical features and the possible influence of MA on QoL measurements.

METHODS

A prospective observational trial was conducted from Oct 2013 until Nov 2016. Therefore an interdisciplinary questionnaire was developed. Overall 250 patients with histological confirmed MA were included with different cancer entities (gynecological, gastrointestinal). The correlation of MA caused symptoms and QoL measurements was assessed using Kendall's tau b. Multivariable logistic regression models were applied to analyze the risks of symptoms or severe limitation in daily activities.

RESULTS

125 questionnaires could be analyzed. The majority of patients with MA had diagnosis of ovarian cancer (68.8%) and were under current cancer treatment (57.6%), mostly chemotherapy. Over 50% reported abdominal tension as major symptom, around 56% of the patients had MA when cancer was firstly diagnosed. Regression analysis showed that patients with MA above 2l were significantly more likely to be harmed in everyday activities. However, the age, gender, type of malignancy and the current treatment (chemotherapy vs. no chemotherapy) had no significant influence.

CONCLUSION

MA has a significantly impact on QoL measurements in cancer patients and might influence everyday activities including basic needs like eating, walking and body care. There is a high need for more information and education of patients with MA.

Strengthening the AntiTumor NK Cell Function for the Treatment of Ovarian Cancer

The crosstalk between cancer cells and host cells is a crucial prerequisite for tumor growth and progression. The cells from both the innate and adaptive immune systems enter into a perverse relationship with tumor cells to create a tumor-promoting and immunosuppressive tumor microenvironment (TME). Epithelial ovarian cancer (EOC), the most lethal of all gynecological malignancies, is characterized by a unique TME that paves the way to the formation of metastasis and mediates therapy resistance through the deregulation of immune surveillance. A characteristic feature of the ovarian cancer TME is the ascites/peritoneal fluid, a malignancy-associated effusion occurring at more advanced stages, which enables the peritoneal dissemination of tumor cells and the formation of metastasis. The standard therapy for EOC involves a combination of debulking surgery and platinum-based chemotherapy. However, most patients experience disease recurrence. New therapeutic strategies are needed to improve the prognosis of patients with advanced EOC. Harnessing the body’s natural immune defenses against cancer in the form of immunotherapy is emerging as an innovative treatment strategy. NK cells have attracted attention as a promising cancer immunotherapeutic target due to their ability to kill malignant cells and avoid healthy cells. Here, we will discuss the recent advances in the clinical application of NK cell immunotherapy in EOC.

Heterotypic CAF-tumor spheroids promote early peritoneal metastatis of ovarian cancer

The study provides insights in HGSOC by identifying that ascitic CAFs selectively recruit ITGA5^high ascitic tumor cells to form heterotypic spheroids named metastatic units (MUs), which actively engage in peritoneal metastasis, discriminates HGSOC from LGSOC, and act as therapeutic targets in hampering OC metastasis.

High-grade serous ovarian cancer (HGSOC) is hallmarked by early onset of peritoneal dissemination, which distinguishes it from low-grade serous ovarian cancer (LGSOC). Here, we describe the aggressive nature of HGSOC ascitic tumor cells (ATCs) characterized by integrin α5^high (ITGA5^high) ATCs, which are prone to forming heterotypic spheroids with fibroblasts. We term these aggregates as metastatic units (MUs) in HGSOC for their advantageous metastatic capacity and active involvement in early peritoneal dissemination. Intriguingly, fibroblasts inside MUs support ATC survival and guide their peritoneal invasion before becoming essential components of the tumor stroma in newly formed metastases. Cancer-associated fibroblasts (CAFs) recruit ITGA5^high ATCs to form MUs, which further sustain ATC ITGA5 expression by EGF secretion. Notably, LGSOC is largely devoid of CAFs and the resultant MUs, which might explain its metastatic delay. These findings identify a specialized MU architecture that amplifies the tumor–stroma interaction and promotes transcoelomic metastasis in HGSOC, providing the basis for stromal fibroblast-oriented interventions in hampering OC peritoneal propagation.

TEM ExosomeAnalyzer: a computer-assisted software tool for quantitative evaluation of extracellular vesicles in transmission electron microscopy images

Extracellular vesicles (EVs) function as important conveyers of information between cells and thus can be exploited as drug delivery systems or disease biomarkers. Transmission electron microscopy (TEM) remains the gold standard method for visualisation of EVs, however the analysis of individual EVs in TEM images is time-consuming if performed manually. Therefore, we present here a software tool for computer-assisted evaluation of EVs in TEM images. TEM ExosomeAnalyzer detects EVs based on their shape and edge contrast criteria and subsequently analyses their size and roundness. The software tool is compatible with common negative staining protocols and isolation methods used in the field of EV research; even with challenging TEM images (EVs both lighter and darker than the background, images containing artefacts or precipitated stain, etc.). If the fully-automatic analysis fails to produce correct results, users can promptly adjust the detected seeds of EVs as well as their boundaries manually. The performance of our tool was evaluated for three different modes with variable levels of human interaction, using two datasets with various heterogeneity. The semi-automatic mode analyses EVs with high success rate in the homogenous dataset (F1 score 0.9094, Jaccard coefficient 0.8218) as well as in the highly heterogeneous dataset containing EVs isolated from cell culture medium and patient samples (F1 score 0.7619, Jaccard coefficient 0.7553). Moreover, the extracted size distribution profiles of EVs isolated from malignant ascites of ovarian cancer patients overlap with those derived by cryo-EM and are comparable to NTA- and TRPS-derived data. In summary, TEM ExosomeAnalyzer is an easy-to-use software tool for evaluation of many types of vesicular microparticles and is available at http://cbia.fi.muni.cz/exosome-analyzer free of charge for non-commercial and research purposes. The web page contains also detailed description how to use the software tool including a video tutorial.

Survival of Ovarian Cancer Patients Is Independent of the Presence of DC and T Cell Subsets in Ascites

Ascites is a prominent feature of ovarian cancer and could serve as liquid biopsy to assess the immune status of patients. Tumor-infiltrating T lymphocytes are correlated with improved survival in ovarian cancer. To investigate whether immune cells in ascites are associated with patient outcome, we analyzed the amount of dendritic cell (DC) and T cell subsets in ascites from ovarian cancer patients diagnosed with high-grade serous cancer (HGSC). Ascites was collected from 62 HGSC patients prior to chemotherapy. Clinicopathological, histological and follow-up data from patients were collected. Ascites-derived immune cells were isolated using density-gradient centrifugation. The presence of myeloid DCs (BDCA-1+, BDCA-3+, CD16+), pDCs (CD123+BDCA-2+), and T cells (CD4+, CD8+) was analyzed using flow cytometry. Complete cytoreduction, response to primary treatment and chemosensitivity were associated with improved patient outcome. In contrast, immune cells in ascites did not significantly correlate with patient survival. However, we observed a trend toward improved outcome for patients having low percentages of CD4+ T cells. Furthermore, we assessed the expression of co-stimulatory and co-inhibitory molecules on T cells and non-immune cells in 10 ascites samples. PD-1 was expressed by 30% of ascites-derived T cells and PD-L1 by 50% of non-immune cells. However, the percentage of DC and T cell subsets in ascites was not directly correlated to the survival of HGSC patients.

Malignant peritoneal effusion acting as a tumor environment in ovarian cancer progression: Impact and significance

Until recently, ovarian cancer research has mainly focused on the tumor cells themselves ignoring for the most part the surrounding tumor environment which includes malignant peritoneal effusions. However, one of the major conceptual advances in oncology over the last few years has been the appreciation that cancer progression cannot be explained by aberrations in cancer cells themselves and is strongly influenced by the surrounding tumor environment. The mechanisms of ovarian cancer progression differ from that of other solid tumors because ovarian cancer cells primarily disseminate within the peritoneal cavity. Malignant peritoneal effusion accumulates in the peritoneal cavity during ovarian cancer progression. These exudative fluids act as a unique tumor environment providing a framework that orchestrates cellular and molecular changes contributing to aggressiveness and disease progression. The composition of ascites, which includes cellular and acellular components, constantly adapts during the course of the disease in response to various cellular cues originating from both tumor and stromal cells. The tumor environment that represents peritoneal effusions closely constitute an ecosystem, with specific cell types and signaling molecules increasing and decreasing during the course of the disease progression creating a single complex network. Although recent advances aiming to understand the ovarian tumor environment have focused one at a time on components, the net impact of the whole environment cannot be understood simply from its parts or outside is environmental context.

Role of the body mass index in the genesis of ascites in ovarian cancer: a forensic case and review of the literature

The ovarian tumour is the seventh female cancer for incidence. In the advanced stages of cancer, tumour cells nourish on the peritoneal serous causing carcinomatosis and peritoneal function abnormalities with liquid build-up inside it. Ascites from peritoneal carcinomatosis is common in patients with ovarian cancer. An obese woman suffering from ovarian cancer was found dead in her home from secondary cardio-respiratory arrest due to Multiple Organ Failure (MOF). An autopsy was performed. The abdominal incision showed an ascitic fluid outflow about 20 litres in volume and a flood about one metre and half. An association between obesity and intraperitoneal fluid volume secondary to peritoneal carcinomatosis has been demonstrated. This finding could improve the prognosis of patients through actions aimed to reduce body weight.

Ascites Volumes and the Ovarian Cancer Microenvironment

Epithelial ovarian cancer is the leading cause of death from gynecologic malignancy among women in developed countries. Epithelial ovarian cancer has a poor prognosis, due to the aggressive characteristics of the disease combined with the lack of effective therapies. Options for late-stage ovarian cancer are limited and invasive, especially once malignant ascites develops. Malignant ascites, a complication observed in terminal ovarian cancer, significantly contributes to poor quality of life and to mortality. Excess accumulation of fluid in the peritoneal cavity occurs due to a combination of impaired fluid drainage and increased net filtration, mostly due to increasing intraperitoneal vascular permeability. Here we applied non-invasive magnetic resonance imaging (MRI) and spectroscopic imaging (MRSI) of syngeneic mouse tumors in vivo, and high-resolution ¹H MRS of mouse tumor extracts, to characterize the relationship between ascites volumes and the vasculature and metabolism of an experimental model of ovarian cancer. Differences were observed in the tumor vasculature and metabolism in tumors based on ascites volumes that provide new insights into the development of this condition.

Key regulator of cellular metabolism, estrogen-related receptor α, a new therapeutic target in endocrine-related gynecological tumor

The estrogen-related receptor α (ERRα), is an orphan transcription factor. Recently, many studies have reported its regulatory mechanisms and transcriptional targets after identification. Therefore, it may be eligible to join the rank of other nuclear receptors that control almost all aspects of cell metabolism. Cellular metabolism reprogramming plays a key role in fueling malignant change. The purpose of this review was to demonstrate that the ERRα plays an important role in the association between gynecological endocrine-related tumors and energy metabolism. Furthermore, regulation of ERRα may represent a promising strategy to induce cellular metabolic vulnerability of cancer from different origins. Thus, a comprehensive understanding of current treatment strategies may be achieved.

Activation of LXRɑ/β by cholesterol in malignant ascites promotes chemoresistance in ovarian cancer

Background

The purpose of this study was to investigate the role of malignant ascites tumor microenvironment in ovarian cancer progression and chemoresistance.

Methods

A total of 45 patients with ovarian cancer and three benign ascites were collected at the time of clinical intervention. Ascites cholesterol levels were quantitated using cholesterol quantitation kit and recurrence free survival (RFS) of ovarian cancer patients were collected. The sensitivity of ovarian cancer cells to cisplatin (CDDP) and paclitaxel (PAC) were assessed by viability assay, flow cytometry and protein expression. Receiver operating characteristics (ROC) curve and Youden index analysis were applied to calculate the optimal cut-off values for ascites cholesterol. Kaplan-Meier curve were applied to compare RFS between high and low ascites cholesterol levels in ovarian cancer patients.

Results

Here we show that cholesterol is elevated in malignant ascites and modulates the sensitivity of ovarian cancer cells to CDDP and PAC by upregulating the expression of drug efflux pump proteins, ABCG2 and MDR1, together with upregulation of LXRɑ/β, the cholesterol receptor. Transfection of LXRɑ/β siRNA inhibited cholesterol-induced chemoresistance and upregulation of MDR1. In addition, the cholesterol level in malignant ascites was negatively correlated with number of CDDP-induced apoptotic cell death, but not with that of PAC-induced apoptotic cell death. Cholesterol depletion by methyl beta cyclodextrin (MβCD) inhibited malignant ascites-induced chemoresistance to CDDP and upregulation of MDR1 and LXRɑ/β. For patients with ovarian cancer, high cholesterol level in malignant ascites correlated with short RFS.

Conclusions

High cholesterol in malignant ascites contributes to poor prognosis in ovarian cancer patients, partly by contributing to multidrug resistance through upregulation of MDR1 via activation of LXRɑ/β.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5152-5) contains supplementary material, which is available to authorized users.

Usefulness of cell-free and concentrated ascites reinfusion therapy in the therapeutic management of advanced ovarian cancer patients with massive ascites

BACKGROUND

The management of refractory ascites in advanced ovarian cancer (AOC) is vital for patients with abdominal distention, respiratory distress, and anorexia due to massive ascites with cancer peritonitis. We analyzed the benefits of concentrated ascites reinfusion therapy (CART) in the management of AOC.

METHODS

We reviewed records of AOC patients who underwent CART between January 2011 and March 2017. We retrospectively analyzed patients' backgrounds and physiological changes, including body weight, abdominal girth, urine volume, blood component values, blood pressure, heart rate, and body temperature before and after CART. We investigated the clinicopathological significance of CART by measuring the mean number of ascites tumor cell (ATC) clusters before CART.

RESULTS

A retrospective analysis was performed on 29 cases of AOC with massive ascites involving 47 CART sessions. The patients' mean age was 56.6 ± 12.8 years, and the mean number of sessions was 1.7 ± 1.2. The mean volume of the processed ascites was 2,937 ± 820 mL, which was concentrated to 272 ± 84 mL containing 85.0 ± 33.2 g protein on average. Significant reductions in abdominal girth (- 5.30 ± 0.65 cm; p < 0.0001) and body weight (- 2.97 ± 0.26 kg; p = 0.0011), increased urine volume (+ 824.29 ± 145.21 mL; p < 0.0001), and improved serum albumin levels (+ 0.18 ± 0.34; p < 0.0001) were observed after CART. Analysis of variance revealed significant elevations in body temperature after CART in 11 patients with a small number of ATC clusters.

CONCLUSIONS

CART is useful for the therapeutic management of AOC patients with refractory massive ascites. Elevations of body temperature after CART may be avoided by the investigation of patients' peritoneal cytology before CART.

Molecular Mechanisms Regulating Organ-Specific Metastases in Epithelial Ovarian Carcinoma

Epithelial ovarian carcinoma is the most predominant type of ovarian carcinoma, the deadliest gynecologic malignancy. It is typically diagnosed late when the cancer has already metastasized. Transcoelomic metastasis is the most predominant mechanism of dissemination from epithelial ovarian carcinoma, although both hematogenously and lymphogenously spread metastases also occur. In this review, we describe molecular mechanisms known to regulate organ-specific metastasis from epithelial ovarian carcinoma. We begin by discussing the sites colonized by metastatic ovarian carcinoma and rank them in the order of prevalence. Next, we review the mechanisms regulating the transcoelomic metastasis. Within this chapter, we specifically focus on the mechanisms that were demonstrated to regulate peritoneal adhesion—one of the first steps in the transcoelomic metastatic cascade. Furthermore, we describe mechanisms of the transcoelomic metastasis known to regulate colonization of specific sites within the peritoneal cavity, including the omentum. Mechanisms underlying hematogenous and lymphogenous metastatic spread are less comprehensively studied in ovarian cancer, and we summarize mechanisms that were identified to date. Lastly, we discuss the outcomes of the clinical trials that attempted to target some of the mechanisms described in this review.

Prognosis Analysis of Histone Deacetylases mRNA Expression in Ovarian Cancer Patients

Histone deacetylases modulate the dynamic balance of histone acetylation and deacetylation in cells, which participate in epigenetic regulations. Accumulated evidence has demonstrated that histone deacetylases are associated with angiogenesis, cell proliferation and survival in a variety of human cancers. However, the expression and distinct prognostic value of histone deacetylases in ovarian cancer have not been well elucidated. In the present study, we collected the overall survival (OS), progress free survival (PFS), and histone deacetylases (HDAC1-11) mRNA expression in ovarian cancer from the Kaplan-Meier plotter online database. We investigated the relationship between histone deacetylases mRNA level and the clinicopathological parameters of the ovarian cancer patients, such as histology subtypes, clinical stages, grades and TP53 mutation. Our analysis data showed that over-expression of HDAC1, HDAC2, HDAC4, HDAC5 and HDAC11 were correlated to poor overall survival and unfavorable progress free survival in all ovarian cancer patients. Notably, the higher level of HDAC11 was associated with the worse OS and PFS for serous/ stage III+IV/ grade III/ TP53 mutation ovarian cancer patients. In conclusion, HDACs may play a crucial role in the prognosis of ovarian cancer, but it is worth noting that HDAC11 may be a biomarker for poor prognosis in ovarian cancer patients.

ERp57‑small interfering RNA silencing can enhance the sensitivity of drug‑resistant human ovarian cancer cells to paclitaxel

ERp57 has been identified to be associated with the chemoresistance of human ovarian cancer. However, its biological roles in the chemoresistance phenotype remain unclear. In the present study, the association of ERp57 with paclitaxel‑resistant cellular behavior was investigated and the sensitivity enhancement of chemoresistant human ovarian cancer cells to paclitaxel was examined using ERp57‑small interfering (si)RNA silencing. Cell viability, cell proliferation, cell apoptosis and cell migration were detected using an MTT assay, clonogenic assay, flow cytometry analysis and transwell assay. Furthermore, mRNA expression levels of ERp57 and protein expression levels of ERp57, STAT3, phosphorylated STAT3, PCNA, nucelolin, TUBB3, P-gp, vimentin, Bcl-2, Bax, Bcl-xl, p53, MMP1, MMP2 and MMP9 of paclitaxel-sensitive human SKOV3 ovarian cancer cells were compared with paclitaxel-resistant counterpart SKOV3/tax using the real-time PCR and western blot analysis. ERp57 was highly expressed in the paclitaxel‑resistant SKOV3/tax cells, and experimental results concluded that the paclitaxel‑resistance phenotype was due primarily to the activation of the STAT3 signaling pathway. ERp57 overexpression by lentiviral particle infection decreased the sensitivity of SKOV3 cells to paclitaxel. Furthermore, ERp57‑siRNA silencing restored paclitaxel sensitivity of SKOV3/tax cells. Notably, the IC50 value of ERp57‑siRNA silenced SKOV3/tax cells was reduced to the original level and colony survival was significantly decreased in comparison with that of SKOV3/tax cells. Additionally, co‑treatment of ERp57‑siRNA silencing and paclitaxel could inhibit the STAT3 signaling pathway and downregulate the expression levels of downstream proteins. Notably, ERp57‑siRNA and 100 nM paclitaxel co‑treatment downregulated Bcl‑2, Bcl‑xl, MMP2, MMP9, TUBB3 and P‑gp expression levels and upregulated the expression of Bax protein. Furthermore, co‑treatment promoted change of the isoform of p53 to p53/p47. Bioinformatics analyses supported the experimental observations that ERp57 was associated with drug resistance in ovarian cancer. The present study implies that ERp57 is a potential therapeutic target for the treatment of paclitaxel‑resistant human ovarian cancer.

IRE1α-XBP1 controls T cell function in ovarian cancer by regulating mitochondrial activity

Tumours evade immune control by creating hostile microenvironments that perturb T cell metabolism and effector function^1-4. However, it remains unclear how intra-tumoral T cells integrate and interpret metabolic stress signals. Here we report that ovarian cancer-an aggressive malignancy that is refractory to standard treatments and current immunotherapies^5-8-induces endoplasmic reticulum stress and activates the IRE1α-XBP1 arm of the unfolded protein response^9,10 in T cells to control their mitochondrial respiration and anti-tumour function. In T cells isolated from specimens collected from patients with ovarian cancer, upregulation of XBP1 was associated with decreased infiltration of T cells into tumours and with reduced IFNG mRNA expression. Malignant ascites fluid obtained from patients with ovarian cancer inhibited glucose uptake and caused N-linked protein glycosylation defects in T cells, which triggered IRE1α-XBP1 activation that suppressed mitochondrial activity and IFNγ production. Mechanistically, induction of XBP1 regulated the abundance of glutamine carriers and thus limited the influx of glutamine that is necessary to sustain mitochondrial respiration in T cells under glucose-deprived conditions. Restoring N-linked protein glycosylation, abrogating IRE1α-XBP1 activation or enforcing expression of glutamine transporters enhanced mitochondrial respiration in human T cells exposed to ovarian cancer ascites. XBP1-deficient T cells in the metastatic ovarian cancer milieu exhibited global transcriptional reprogramming and improved effector capacity. Accordingly, mice that bear ovarian cancer and lack XBP1 selectively in T cells demonstrate superior anti-tumour immunity, delayed malignant progression and increased overall survival. Controlling endoplasmic reticulum stress or targeting IRE1α-XBP1 signalling may help to restore the metabolic fitness and anti-tumour capacity of T cells in cancer hosts.

Epithelial-mesenchymal transition is activated in CD44-positive malignant ascites tumor cells of gastrointestinal cancer

Disseminated cancer cells in malignant ascites possess unique properties that differ from primary tumors. However, the biological features of ascites tumor cells (ATC) have not been fully investigated. By analyzing ascites fluid from 65 gastrointestinal cancer patients, the distinguishing characteristics of ATC were identified. High frequency of CD44⁺ cells was observed in ATC using flow cytometry (n = 48). Multiplex quantitative PCR (n = 15) showed higher gene expression of epithelial‐mesenchymal transition (EMT)‐related genes and transforming growth factor beta (TGF‐beta)‐related genes in ATC than in the primary tissues. Immunohistochemistry (n = 10) showed that ATC also had much higher expression of phosphorylated SMAD2 than that in the corresponding primary tissues. TGF‐beta 1 was detected in all cases of malignant ascites by enzyme‐linked immunoassay (n = 38), suggesting the possible interaction of ATC and the ascites microenvironment. In vitro experiments revealed that these ATC properties were maintained by TGF‐beta 1 in cultured ATC(n = 3). Here, we showed that ATCrevealed high frequencies of CD44 and possessed distinct EMT features from primary tissues that were mainly maintained by TGF‐beta 1 in the ascites.

Immunohistochemical Characterization Improves the Reproducibility of the Histological Diagnosis of Ovarian Carcinoma

Background: Ovarian cancer is the leading cause of gynecologic cancer-related death. Histological assessment remains the standard clue for the diagnosis of ovarian carcinoma. Misinterpretation and inconsistent application of histological criteria may lead to significant interobserver variability and poor reproducibility of the diagnosis. In this study, we investigated the discrepancy in histological diagnosis and the significance of a designed panel of immunohistochemical markers for the improvement of the diagnostic reproducibility of ovarian carcinomas. Methods: We performed a retrospective study on 74 ovarian carcinomas. All tumor slides were independently reviewed by two pathologists. The results for seven available immunomarkers as p53, WT-1, p16INK4A, CK7, CK20, and estrogen and progesterone receptors were determined for all cases by immunohistochemistry. Results: The histological diagnosis review performed using standard histology showed a concordance of diagnoses in 86% of cases with Cohen’s kappa of 0.80. Immunohistochemical results increased significantly the diagnosis reproducibility with a concordance of 91% and a Cohen’s kappa of 0.86 (P = 0.001). Conclusion: Although the histological diagnosis remains reliable, the use of a designed panel of immunohistochemical markers improves significantly the interobserver concordance and the classification accuracy of ovarian carcinomas.

Anetumab ravtansine inhibits tumor growth and shows additive effect in combination with targeted agents and chemotherapy in mesothelin-expressing human ovarian cancer models

Despite the recent advances in the treatment of ovarian cancer, it remains an area of high unmet medical need. Epithelial ovarian cancer is associated with high levels of mesothelin expression, and therefore, mesothelin is an attractive candidate target for the treatment of this disease. Herein, we investigated the antitumor efficacy of the mesothelin-targeting antibody-drug conjugate (ADC) anetumab ravtansine as a novel treatment option for ovarian cancer in monotherapy and in combination with the antitumor agents pegylated liposomal doxorubicin (PLD), carboplatin, copanlisib and bevacizumab. Anetumab ravtansine showed potent antitumor activity as a monotherapy in ovarian cancer models with high mesothelin expression. No activity was seen in mesothelin-negative models. The combination of anetumab ravtansine with PLD showed additive anti-proliferative activity in vitro, which translated into improved therapeutic in vivo efficacy in ovarian cancer cell line- and patient-derived xenograft (PDX) models compared to either agents as a monotherapy. The combination of anetumab ravtansine with the PI3Kα/δ inhibitor copanlisib was additive in the OVCAR-3 and OVCAR-8 cell lines in vitro, showing increased apoptosis in response to the combination treatment. In vivo, the combination of anetumab ravtansine with copanlisib resulted in more potent antitumor activity than either of the treatments alone. Likewise, the combination of anetumab ravtansine with carboplatin or bevacizumab showed improved in vivo efficacy in the ST081 and OVCAR-3 models, respectively. All combinations were well-tolerated. Taken together, these data support the development of anetumab ravtansine for ovarian cancer treatment and highlight its suitability for combination therapy with PLD, carboplatin, copanlisib, or bevacizumab.

Activation of B-1 Cells Promotes Tumor Cell Killing in the Peritoneal Cavity

Metastatic cancer involving spread to the peritoneal cavity is referred to as peritoneal carcinomatosis and has a very poor prognosis. Activating the antitumor immune response in the characteristically immune-suppressive peritoneal environment presents a potential strategy to treat this disease. In this study, we show that a toll-like receptor (TLR) and C-type lectin receptor (CLR) agonist pairing of monophosphoryl lipid A (MPL) and trehalose-6,6'-dicorynomycolate (TDCM) effectively inhibits tumor growth and ascites development in a mouse model of aggressive mammary cancer-induced peritoneal carcinomatosis. MPL/TDCM treatment similarly inhibited peritoneal EL4 tumor growth and ascites development. These effects were not observed in mice lacking B cells or mice lacking CD19, which are deficient in B-1a cells, an innate-like B-cell population enriched in the peritoneal cavity. Remarkably, adoptive transfer of B-1a cells, but not splenic B cells from WT mice, restored MPL/TDCM-induced protection in mice with B-cell defects. Treatment induced B-1 cells to rapidly produce high levels of natural IgM reactive against tumor-associated carbohydrate antigens. Consistent with this, we found significant deposition of IgM and C3 on peritoneal tumor cells as early as 5 days post-treatment. Mice unable to secrete IgM or complement component C4 were not protected by MPL/TDCM treatment, indicating tumor killing was mediated by activation of the classical complement pathway. Collectively, our findings reveal an unsuspected role for B-1 cell-produced natural IgM in providing protection against tumor growth in the peritoneal cavity, thereby highlighting potential opportunities to develop novel therapeutic strategies for the prevention and treatment of peritoneal metastases. SIGNIFICANCE: This work identifies a critical antitumor role for innate-like B cells localized within the peritoneal cavity and demonstrates a novel strategy to activate their tumor-killing potential.See related commentary by Tripodo, p. 5.

Review: Mechanotransduction in ovarian cancer: Shearing into the unknown

Ovarian cancer remains a deadly diagnosis with an 85% recurrence rate and a 5-year survival rate of only 46%. The poor outlook of this disease has improved little over the past 50 years owing to the lack of early detection, chemoresistance and the complex tumor microenvironment. Within the peritoneal cavity, the presence of ascites stimulates ovarian tumors with shear stresses. The stiff environment found within the tumor extracellular matrix and the peritoneal membrane are also implicated in the metastatic potential and epithelial to mesenchymal transition (EMT) of ovarian cancer. Though these mechanical cues remain highly relevant to the understanding and treatment of ovarian cancers, our current knowledge of their biological processes and their clinical relevance is deeply lacking. Seminal studies on ovarian cancer mechanotransduction have demonstrated close ties between mechanotransduction and ovarian cancer chemoresistance, EMT, enhanced cancer stem cell populations, and metastasis. This review summarizes our current understanding of ovarian cancer mechanotransduction and the gaps in knowledge that exist. Future investigations on ovarian cancer mechanotransduction will greatly improve clinical outcomes via systematic studies that determine shear stress magnitude and its influence on ovarian cancer progression, metastasis, and treatment.