Epithelial ovarian cancer experimental models

Oncolytic adenovirus MEM-288 encoding membrane-stable CD40L and IFNβ induces an anti-tumor immune response in high grade serous ovarian cancer

Single agent immune checkpoint inhibitors have been ineffective for patients with advanced stage and recurrent high grade serous ovarian cancer (HGSOC). Using pre-clinical models of HGSOC, we evaluated the anti-tumor and immune stimulatory effects of an oncolytic adenovirus, MEM-288. This conditionally replicative virus encodes a modified membrane stable CD40L and IFNβ. We demonstrated this virus successfully infects HGSOC cell lines and primary human ascites samples in vitro. We evaluated the anti-tumor and immunostimulatory activity in vivo in immune competent mouse models. Intraperitoneal delivery of MEM-288 decreased ascites and solid tumor burden compared to controls, and treatment generated a systemic anti-tumor immune response. The tumor microenvironment had a higher proportion of anti-tumor macrophages and decreased markers of angiogenesis. MEM-288 is a promising immunotherapy agent in HGSOC, with further pre-clinical studies required to understand the mechanism of action in the peritoneal microenvironment and clinical activity in combination with other therapies.

Comparative transcriptomic study on the ovarian cancer between chicken and human

The laying hen is the spontaneous model of ovarian tumor. A comprehensive comparison based on RNA-seq from hens and women may shed light on the molecular mechanisms of ovarian cancer. We performed next-generation sequencing of microRNA and mRNA expression profiles in 9 chicken ovarian cancers and 4 normal ovaries, which has been deposited in GSE246604. Together with 6 public datasets (GSE21706, GSE40376, GSE18520, GSE27651, GSE66957, TCGA-OV), we conducted a comparative transcriptomics study between chicken and human. In the present study, miR-451, miR-2188-5p, and miR-10b-5p were differentially expressed in normal ovaries, early- and late-stage ovarian cancers. We also disclosed 499 up-regulated genes and 1,061 down-regulated genes in chicken ovarian cancer. The molecular signals from 9 cancer hallmarks, 25 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and 369 Gene Ontology (GO) pathways exhibited abnormalities in ovarian cancer compared to normal ovaries via Gene Set Enrichment Analysis (GSEA). In the comparative analysis across species, we have uncovered the conservation of 5 KEGG and 76 GO pathways between chicken and human including the mismatch repair and ECM receptor interaction pathways. Moreover, a total of 174 genes contributed to the core enrichment for these KEGG and GO pathways were identified. Among these genes, the 22 genes were found to be associated with overall survival in patients with ovarian cancer. In general, we revealed the microRNA profiles of ovarian cancers in hens and updated the mRNA profiles previously derived from microarrays. And we also disclosed the molecular pathways and core genes of ovarian cancer shared between hens and women, which informs model animal studies and gene-targeted drug development.

Netrin signaling mediates survival of dormant epithelial ovarian cancer cells

Dormancy in cancer is a clinical state in which residual disease remains undetectable for a prolonged duration. At a cellular level, rare cancer cells cease proliferation and survive chemotherapy and disseminate disease. We created a suspension culture model of high-grade serous ovarian cancer (HGSOC) dormancy and devised a novel CRISPR screening approach to identify survival genes in this context. In combination with RNA-seq, we discovered the Netrin signaling pathway as critical to dormant HGSOC cell survival. We demonstrate that Netrin-1, -3, and its receptors are essential for low level ERK activation to promote survival, and that Netrin activation of ERK is unable to induce proliferation. Deletion of all UNC5 family receptors blocks Netrin signaling in HGSOC cells and compromises viability during the dormancy step of dissemination in xenograft assays. Furthermore, we demonstrate that Netrin-1 and -3 overexpression in HGSOC correlates with poor outcome. Specifically, our experiments reveal that Netrin overexpression elevates cell survival in dormant culture conditions and contributes to greater spread of disease in a xenograft model of abdominal dissemination. This study highlights Netrin signaling as a key mediator HGSOC cancer cell dormancy and metastasis.

Matriptase drives dissemination of ovarian cancer spheroids by a PAR-2/PI3K/Akt/MMP9 signaling axis

The transmembrane serine protease matriptase is a key regulator of both barrier-disruptive and protective epithelial cell-cell interactions. Elevated matriptase is a consistent feature of epithelial ovarian cancers (OvCa), where multicellular spheroids shed from the primary tumor into the peritoneal cavity are critical drivers of metastasis. Dynamic cell-to-cell adhesive contacts are required for spheroid formation and maintenance. Here, we show that overactive matriptase, reflected in an increased ratio of matriptase to its inhibitor hepatocyte growth factor activator inhibitor 1 (HAI-1), disrupts cell-cell contacts to produce loose prometastatic spheroids that display increased mesothelial cell adhesion and submesothelial invasion. We show that these activities are dependent on the matriptase activation of a protease-activated receptor-2 (PAR-2) signaling pathway involving PI3K/Akt and MMP9-induced disruption of cell-cell adhesion by the release of the soluble E-cadherin ectodomain. These data reveal a novel pathological connection between matriptase activation of PAR-2 and disruption of cell-cell adhesion, and support the clinical investigation of this signaling axis as a therapeutic strategy for aggressive metastatic OvCa.

Exploiting a living biobank to delineate mechanisms underlying disease-specific chromosome instability

Chromosome instability (CIN) is a cancer hallmark that drives tumour heterogeneity, phenotypic adaptation, drug resistance and poor prognosis. High-grade serous ovarian cancer (HGSOC), one of the most chromosomally unstable tumour types, has a 5-year survival rate of only ~30% - largely due to late diagnosis and rapid development of drug resistance, e.g., via CIN-driven ABCB1 translocations. However, CIN is also a cell cycle vulnerability that can be exploited to specifically target tumour cells, illustrated by the success of PARP inhibitors to target homologous recombination deficiency (HRD). However, a lack of appropriate models with ongoing CIN has been a barrier to fully exploiting disease-specific CIN mechanisms. This barrier is now being overcome with the development of patient-derived cell cultures and organoids. In this review, we describe our progress building a Living Biobank of over 120 patient-derived ovarian cancer models (OCMs), predominantly from HGSOC. OCMs are highly purified tumour fractions with extensive proliferative potential that can be analysed at early passage. OCMs have diverse karyotypes, display intra- and inter-patient heterogeneity and mitotic abnormality rates far higher than established cell lines. OCMs encompass a broad-spectrum of HGSOC hallmarks, including a range of p53 alterations and BRCA1/2 mutations, and display drug resistance mechanisms seen in the clinic, e.g., ABCB1 translocations and BRCA2 reversion. OCMs are amenable to functional analysis, drug-sensitivity profiling, and multi-omics, including single-cell next-generation sequencing, and thus represent a platform for delineating HGSOC-specific CIN mechanisms. In turn, our vision is that this understanding will inform the design of new therapeutic strategies.

Host obesity alters the ovarian tumor immune microenvironment and impacts response to standard of care chemotherapy

BACKGROUND

The majority of women with epithelial ovarian cancer (OvCa) are diagnosed with metastatic disease, resulting in a poor 5-year survival of 31%. Obesity is a recognized non-infectious pandemic that increases OvCa incidence, enhances metastatic success and reduces survival. We have previously demonstrated a link between obesity and OvCa metastatic success in a diet-induced obesity mouse model wherein a significantly enhanced tumor burden was associated with a decreased M1/M2 tumor-associated macrophage ratio (Liu Y et al. Can, Res. 2015; 75:5046-57).

METHODS

The objective of this study was to use pre-clinical murine models of diet-induced obesity to evaluate the effect of a high fat diet (HFD) on response to standard of care chemotherapy and to assess obesity-associated changes in the tumor microenvironment. Archived tumor tissues from ovarian cancer patients of defined body mass index (BMI) were also evaluated using multiplexed immunofluorescence analysis of immune markers.

RESULTS

We observed a significantly diminished response to standard of care paclitaxel/carboplatin chemotherapy in HFD mice relative to low fat diet (LFD) controls. A corresponding decrease in the M1/M2 macrophage ratio and enhanced tumor fibrosis were observed both in murine DIO studies and in human tumors from women with BMI > 30.

CONCLUSIONS

Our data suggest that the reported negative impact of obesity on OvCa patient survival may be due in part to the effect of the altered M1/M2 tumor-associated macrophage ratio and enhanced fibrosis on chemosensitivity. These data demonstrate a contribution of host obesity to ovarian tumor progression and therapeutic response and support future combination strategies targeting macrophage polarization and/or fibrosis in the obese host.

Patient-derived organoids in ovarian cancer: Current research and its clinical relevance

Regardless of recent advances in cancer treatment, ovarian cancer (OC) patients have had a five-year survival rate of 48% in the last few decades. Diagnosis at the advanced stage, disease recurrence, and lack of early biomarkers are the severe clinical challenges associated with disease survival rate. Identifying tumor origin and developing precision drugs will effectively advance OC patient's treatment. The lack of a proper platform to identify and develop new therapeutic strategies in OC treatment necessitates searching for a suitable model to address tumor recurrence and therapeutic resistance. The development of the OC patient-derived organoid model provided a unique platform to identify the exact origin of high-grade serous OC, drug screening, and the development of precision medicine. This review provides an overview of recent progress in developing patient-derived organoids and their clinical relevance. Here, we outline their uses for transcriptomics and genomics profiling, drug screening, translational study, and their future perspective and clinical outlook as a model to advance OC research that could offer a promising approach for developing precision medicine.

Precision-engineered biomimetics: the human fallopian tube

The fallopian tube has an essential role in several physiological and pathological processes from pregnancy to ovarian cancer. However, there are no biologically relevant models to study its pathophysiology. The state-of-the-art organoid model has been compared to two-dimensional tissue sections and molecularly assessed providing only cursory analyses of the model's accuracy. We developed a novel multi-compartment organoid model of the human fallopian tube that was meticulously tuned to reflect the compartmentalization and heterogeneity of the tissue's composition. We validated this organoid's molecular expression patterns, cilia-driven transport function, and structural accuracy through a highly iterative platform wherein organoids are compared to a three-dimensional, single-cell resolution reference map of a healthy, transplantation-quality human fallopian tube. This organoid model was precision-engineered to match the human microanatomy.

One sentence summary

Tunable organoid modeling and CODA architectural quantification in tandem help design a tissue-validated organoid model.

Specific and Long-Term Luminescent Monitoring of Hydrogen Peroxide in Tumor Metastasis

Luminescent monitoring of endogenous hydrogen peroxide (H₂ O₂ ) in tumors is conducive to understanding metastasis and developing novel therapeutics. The clinical transformation is obstructed by the limited light penetration depth, toxicity of nano-probes, and lack of long-term monitoring modes of up to days or months. New monitoring modes are introduced via specific probes and implantable devices, which can achieve real-time monitoring with a readout frequency of 0.01 s or long-term monitoring for months to years. Near-infrared dye-sensitized upconversion nanoparticles (UCNPs) are fabricated as the luminescent probes, and the specificity to reactive oxygen species is subtly regulated by the self-assembled monolayers on the surfaces of UCNPs. Combined with the passive implanted system, a 20-day monitoring of H₂ O₂ in the rat model of ovarian cancer with peritoneal metastasis is achieved, in which the limited light penetration depth and toxicity of nano-probes are circumvented. The developed monitoring modes show great potential in accelerating the clinical transformation of nano-probes and biochemical detection methods.

Insights into high-grade serous carcinoma pathobiology using three-dimensional culture model systems

Epithelial ovarian cancer (EOC) research has become more complex as researchers try to fully understand the metastatic process. Especially as we delve into the concept of tumour dormancy, where cells transition between proliferative and dormant states to survive during disease progression. Thus, the in vitro models used to conduct this research need to reflect this vast biological complexity. The innovation behind the many three-dimensional (3D) spheroid models has been refined to easily generate reproducible spheroids so that we may understand the various molecular signaling changes of cells during metastasis and determine therapeutic efficacy of treatments. This ingenuity was then used to develop the 3D ex vivo patient-derived organoid model, as well as multiple co-culture model systems for EOC research. Although, researchers need to continue to push the boundaries of these current models for in vitro and even in vivo work in the future. In this review, we describe the 3D models already in use, where these models can be developed further and how we can use these models to gain the most knowledge on EOC pathogenesis and discover new targeted therapies.

A 3D multi-cellular tissue model of the human omentum to study the formation of ovarian cancer metastasis

Reliable and predictive experimental models are urgently needed to study metastatic mechanisms of ovarian cancer cells in the omentum. Although models for ovarian cancer cell adhesion and invasion were previously investigated, the lack of certain omental cell types, which influence the metastatic behavior of cancer cells, limits the application of these tissue models. Here, we describe a 3D multi-cellular human omentum tissue model, which considers the spatial arrangement of five omental cell types. Reproducible tissue models were fabricated combining permeable cell culture inserts and bioprinting technology to mimic metastatic processes of immortalized and patient-derived ovarian cancer cells. The implementation of an endothelial barrier further allowed studying the interaction between cancer and endothelial cells during hematogenous dissemination and the impact of chemotherapeutic drugs. This proof-of-concept study may serve as a platform for patient-specific investigations in personalized oncology in the future.

COMMD3-Mediated Endosomal Trafficking of HER2 Inhibits the Progression of Ovarian Carcinoma

The dysregulated endocytic traffic of oncogenic receptors, such as the EGFR family especially HER2, contributes to the uncontrolled activation of the downstream oncogenic signaling and progression of various carcinomas, including 90% of ovarian carcinoma. However, the key regulators in the intracellular trafficking of HER2 and their impacts for cancer progression remain largely unknown. In this study, through a genome-wide CRISPR/Cas9 screening for key genes affecting the peritoneal disseminated metastasis of ovarian carcinoma, we identified a member of COMMD family, that is, COMMD3, as a key regulator in the endosomal trafficking of HER2. In the patients with high-grade serous ovarian carcinoma (HGSOC), the expression of COMMD3 is dramatically decreased in the peritoneal disseminated ovarian carcinoma cells comparing with that in the primary ovarian carcinoma cells. COMMD3 greatly inhibits the proliferation, migration, and epithelial-mesenchymal transition (EMT) of HGSOC cells, and dramatically suppresses the tumor growth, the formation of malignant ascites, and the peritoneal dissemination of cancer cells in the orthotopic murine model of HGSOC. Further transcriptome analysis reveals that silencing COMMD3 boosts the activation of HER2 downstream signaling. As a component in the Retriever-associated COMMD/CCDC22/CCDC93 complex responsible for the recognition and recycling of membrane receptors, COMMD3 physically interacts with HER2 for directing it to the slow recycling pathway, leading to the attenuated downstream tumor-promoting signaling.

IMPLICATIONS

Collectively, this study reveals a novel HER2 inactivation mechanism with a high value for the clinic diagnosis of new ovarian carcinoma types and the design of new therapeutic strategy.

Diallyl trisulfide alleviates chemotherapy sensitivity of ovarian cancer via the AMPK/SIRT1/PGC1α pathway

Platinum-based chemotherapy promotes drug resistance in ovarian cancer. We investigated the antichemoresistance characteristics of diallyl trisulfide (DATS) in cisplatin-resistant ovarian cancer cells, in vitro and in vivo. Previous preclinical studies have revealed that DATS regulates distinct hallmark cancer-signaling pathways. The cell cycle pathway is the most investigated signaling pathway in DATS. Additionally, post-DATS treatment has been found to promote proapoptotic capacity through the regulation of intrinsic and extrinsic apoptotic pathway components. In the present study, we found that treating cisplatin-sensitive and cisplatin-resistant ovarian cell lines with DATS inhibited their proliferation and reduced their IC_50. It induced cell apoptosis and promoted oxidative phosphorylation through the regulation of the AMPK/SIRT1/PGC1α pathway, OXPHOS, and enhanced chemotherapy sensitivity. DATS treatment alleviated glutamine consumption in cisplatin-resistant cells. Our findings highlight the role of DATS in overcoming drug resistance in ovarian cancer in vitro and in vivo. In addition, we elucidated the role of the AMPK/SIRT1/PGC1α signaling pathway as a potential target for the treatment of drug-resistant ovarian cancer.

Combined inhibition of BADSer99 phosphorylation and PARP ablates models of recurrent ovarian carcinoma

Background

Poly (ADP-ribose) polymerase inhibitors (PARPis) have been approved for the treatment of recurrent epithelial ovarian cancer (EOC), regardless of BRCA status or homologous recombination repair deficiency. However, the low response of platinum-resistant EOC, the emergence of resistance in BRCA-deficient cancer, and therapy-associated toxicities in patients limit the clinical utility of PARPis in recurrent EOC.

Methods

The association of phosphorylated (p) BADS99 with clinicopathological parameters and survival outcomes in an EOC cohort was assessed by immunohistochemistry. The therapeutic synergy, and mechanisms thereof, between a pBADS99 inhibitor and PARPis in EOC was determined in vitro and in vivo using cell line and patient-derived models.

Results

A positive correlation between pBADS99 in EOC with higher disease stage and poorer survival is observed. Increased pBADS99 in EOC cells is significantly associated with BRCA-deficiency and decreased Cisplatin or Olaparib sensitivity. Pharmacological inhibition of pBADS99 synergizes with PARPis to enhance PARPi IC₅₀ and decreases survival, foci formation, and growth in ex vivo culture of EOC cells and patient-derived organoids (PDOs). Combined inhibition of pBADS99 and PARP in EOC cells or PDOs enhances DNA damage but impairs PARPi stimulated DNA repair with a consequent increase in apoptosis. Inhibition of BADS99 phosphorylation synergizes with Olaparib to suppress the xenograft growth of platinum-sensitive and resistant EOC. Combined pBADS99-PARP inhibition produces a complete response in a PDX derived from a patient with metastatic and chemoresistant EOC.

Conclusions

A rational and efficacious combination strategy involving combined inhibition of pBADS99 and PARP for the treatment of recurrent EOC is presented.

Ovarian cancer is difficult to successfully treat because it often recurs as the cancer becomes resistant to drugs used to treat it. As such, new drugs or combinations of drugs are needed to treat patients with recurrent ovarian cancer. Here, a drug combination is reported that is effective in experimental models of ovarian cancer, including those derived from patients. The combination approach uses drugs that have previously been approved for use in patients, known as PARP inhibitors, and another drug to inhibit cancer cell survival by targeting activation of a specific protein involved in cancer cell survival. The net effect of this drug combination in ovarian cancer models is greater than the sum of the drugs used individually. With further testing, this combination may offer a potential strategy to treat patients with recurrent ovarian cancer.

Zhang et al. test the therapeutic potential of an inhibitor of BAD phosphorylation, NPB, in epithelial ovarian cancer. The authors show that the small molecule synergises with PARP inhibition to kill patient-derived ovarian cancer organoids and suppress the growth of xenograft tumours, including a cisplatin-resistant model.

The Development of a Three-Dimensional Platform for Patient-Derived Ovarian Cancer Tissue Models: A Systematic Literature Review

There is an unmet biomedical need for ex vivo tumour models that would predict drug responses and in turn help determine treatment regimens and potentially predict resistance before clinical studies. Research has shown that three dimensional models of ovarian cancer (OvCa) are more realistic than two dimensional in vitro systems as they are able to capture patient in vivo conditions in more accurate manner. The vast majority of studies aiming to recapitulate the ovarian tumour morphology, behaviors, and study chemotherapy responses have been using ovarian cancer cell lines. However, despite the advantages of utilising cancer cell lines to set up a platform, they are not as informative as systems applying patient derived cells, as cell lines are not able to recapitulate differences between each individual patient characteristics. In this review we discussed the most recent advances in the creation of 3D ovarian cancer models that have used patient derived material, the challenges to overcome and future applications.

Rab11a promotes the malignant progression of ovarian cancer by inducing autophagy

BACKGROUND

Rab11a is a novel identified tumorigenic factor involved in different cancers.

OBJECTIVE

This study aimed to assess the biological function of Rab11a in ovarian cancer (OC).

METHODS

GEPIA database and real-time PCR were used to determine Rab11a expression in OC tissues and normal ovarian tissues. CCK-8, cell cycle, wound healing, transwell, and enzyme linked immunosorbent assay were used to detect the effects of Rab11a knockdown or overexpression on the proliferation, migration, and invasion of OC cells. Western blot analysis of autophagy-related markers and immunofluorescence staining of LC3 were performed to determine autophagy induction in Rab11a-silenced or overexpressed OC cells. Moreover, autophagy inhibitor 3-MA was employed to clarify the effects of Rab11a-regulated autophagy on the malignant phenotypes of OC cells.

RESULTS

The mRNA level of Rab11a was increased in tumor tissues from OC patients as compared to the normal ovarian tissues. Knockdown of Rab11a in OVCAR-3 cells inhibited the growth of OC cells and led to cell cycle arrest, accompanied by reduced expression of PCNA and Cyclin D1. Rab11a deficiency suppressed migration and invasion of OC cells, accompanied by decreased secretion of MMP-2 and MMP-9. Silence of Rab11a impeded autophagy induction, as evidenced by decreased LC3 puncta formation, reduced abundance of LC3II and Beclin1, and increased p62 protein expression. In contrast, the ectopic expression of Rab11a in A2780 cells exerted opposite effects. Interestingly, autophagy inhibitor 3-MA abolished the effects of Rab11a overexpression on autophagy, proliferation, migration, and invasion.

CONCLUSIONS

Rab11a promotes the malignant phenotypes of OC cells by inducing autophagy.

MEX3A promotes the malignant progression of ovarian cancer by regulating intron retention in TIMELESS

The latest research shows that RNA-binding proteins (RBPs) could serve as novel potential targets for cancer therapy. We used bioinformatics analysis to screen and identify the key RBPs in ovarian cancer, from which we found that Mex-3 RNA Binding Family Member A (MEX3A) was intimately associated with the clinical prognosis of ovarian cancer. Nevertheless, little is known about its biological roles in ovarian cancer. In this case, we observed that MEX3A was highly overexpressed in fresh-frozen ovarian cancer tissues. MEX3A knockdown suppressed the development and invasion of ovarian cancer cells, while MEX3A overexpression promoted the proliferation and invasion of ovarian cancer cells. Mechanistically, TIMELESS was the critical downstream target gene of MEX3A, as demonstrated through alternative splicing event analysis based on RNA-seq. MEX3A knockdown resulted in retention of intron twenty-three of TIMELESS mRNA and decreased TIMELESS mRNA owing to stimulation of nonsense-mediated RNA decay (NMD). Additionally, we found that TIMELESS overexpression with MEX3A knockdown partially restored the proliferation ability of ovarian cancer cells. The results of this paper demonstrated that the MEX3A/TIMELESS signaling pathway was a key regulator of ovarian cancer, and MEX3A was a novel possible treatment target for ovarian cancer patients.

Another Wrinkle with Age: Aged Collagen and Intra-peritoneal Metastasis of Ovarian Cancer

Background

Age is the most significant risk factor for ovarian cancer (OvCa), the deadliest gynecologic malignancy. Metastasizing OvCa cells adhere to the omentum, a peritoneal structure rich in collagen, adipocytes, and immune cells. Ultrastructural changes in the omentum and the omental collagen matrix with aging have not been evaluated.

Aim

The aim of this study was to test the hypothesis that age-related changes in collagen in the ovarian tumor microenvironment promote OvCa metastatic success in the aged host.

Methods/Results

Young (3-6 months) and aged mice (20-23 months) were used to study the role of aging in metastatic success. Intra-peritoneal (IP) injection of ID8Trp53 ^-/- ovarian cancer cells showed enhanced IP dissemination in aged vs young mice. In vitro assays using purified collagen demonstrated reduced collagenolysis of aged fibers, as visualized using scanning electron microscopy (SEM) and quantified with a hydroxyproline release assay. Omental tumors in young and aged mice showed similar collagen deposition; however enhanced intra-tumoral collagen remodeling was seen in aged mice probed with a biotinylated collagen hybridizing peptide (CHP). In contrast, second harmonic generation (SHG) microscopy showed significant differences in collagen fiber structure and organization in omental tissue and SEM demonstrated enhanced omental fenestration in aged omenta. Combined SHG and Alexa Fluor-CHP microscopy in vivo demonstrated that peri-tumoral collagen was remodeled more extensively in young mice. This collagen population represents truly aged host collagen, in contrast to intra-tumoral collagen that is newly synthesized, likely by cancer associated fibroblasts (CAFs).

Conclusions

Our results demonstrate that tumors in an aged host can grow with minimal collagen remodeling, while tumors in the young host must remodel peri-tumoral collagen to enable effective proliferation, providing a mechanism whereby age-induced ultrastructural changes in collagen and collagen-rich omenta establish a permissive pre-metastatic niche contributing to enhanced OvCa metastatic success in the aged host.

Principles of dormancy evident in high-grade serous ovarian cancer

In cancer, dormancy refers to a clinical state in which microscopic residual disease becomes non-proliferative and is largely refractory to chemotherapy. Dormancy was first described in breast cancer where disease can remain undetected for decades, ultimately leading to relapse and clinical presentation of the original malignancy. A long latency period can be explained by withdrawal from cell proliferation (cellular dormancy), or a balance between proliferation and cell death that retains low levels of residual disease (tumor mass dormancy). Research into cellular dormancy has revealed features that define this state. They include arrest of cell proliferation, altered cellular metabolism, and unique cell dependencies and interactions with the microenvironment. These characteristics can be shared by dormant cells derived from disparate primary disease sites, suggesting common features exist between them.

High-grade serous ovarian cancer (HGSOC) disseminates to locations throughout the abdominal cavity by means of cellular aggregates called spheroids. These growth-arrested and therapy-resistant cells are a strong contributor to disease relapse. In this review, we discuss the similarities and differences between ovarian cancer cells in spheroids and dormant properties reported for other cancer disease sites. This reveals that elements of dormancy, such as cell cycle control mechanisms and changes to metabolism, may be similar across most forms of cellular dormancy. However, HGSOC-specific aspects of spheroid biology, including the extracellular matrix organization and microenvironment, are obligatorily disease site specific. Collectively, our critical review of current literature highlights places where HGSOC cell dormancy may offer a more tractable experimental approach to understand broad principles of cellular dormancy in cancer.

Cancer-Associated Fibroblasts: Mechanisms of Tumor Progression and Novel Therapeutic Targets

Simple Summary

The tumor microenvironment plays an important role in determining the biological behavior of several of the more aggressive malignancies. Among the various cell types evident in the tumor “field”, cancer-associated fibroblasts (CAFs) are a heterogenous collection of activated fibroblasts secreting a wide repertoire of factors that regulate tumor development and progression, inflammation, drug resistance, metastasis and recurrence. Insensitivity to chemotherapeutics and metastatic spread are the major contributors to cancer patient mortality. This review discusses the complex interactions between CAFs and the various populations of normal and neoplastic cells that interact within the dynamic confines of the tumor microenvironment with a focus on the involved pathways and genes.

Abstract

Cancer-associated fibroblasts (CAFs) are a heterogenous population of stromal cells found in solid malignancies that coexist with the growing tumor mass and other immune/nonimmune cellular elements. In certain neoplasms (e.g., desmoplastic tumors), CAFs are the prominent mesenchymal cell type in the tumor microenvironment, where their presence and abundance signal a poor prognosis in multiple cancers. CAFs play a major role in the progression of various malignancies by remodeling the supporting stromal matrix into a dense, fibrotic structure while secreting factors that lead to the acquisition of cancer stem-like characteristics and promoting tumor cell survival, reduced sensitivity to chemotherapeutics, aggressive growth and metastasis. Tumors with high stromal fibrotic signatures are more likely to be associated with drug resistance and eventual relapse. Clarifying the molecular basis for such multidirectional crosstalk among the various normal and neoplastic cell types present in the tumor microenvironment may yield novel targets and new opportunities for therapeutic intervention. This review highlights the most recent concepts regarding the complexity of CAF biology including CAF heterogeneity, functionality in drug resistance, contribution to a progressively fibrotic tumor stroma, the involved signaling pathways and the participating genes.

Ovarian Cancer: Applications of Chickens to Humans

The lack of preclinical models of spontaneous ovarian cancer (OVCA), a fatal gynecological malignancy, is a significant barrier to generating information on early changes indicative of OVCA. In contrast to rodents, laying hens develop OVCA spontaneously, with remarkable similarities to OVCA in women regarding tumor histology, OVCA dissemination, immune responses, and risk factors. These important features of OVCA will be useful to develop an early detection test for OVCA, which would significantly reduce mortality rates; preventive strategies; immunotherapeutics; prevention of resistance to chemotherapeutics; and exploration of gene therapies. A transvaginal ultrasound (TVUS) imaging method for imaging of hen ovarian tumors has been developed. Hens can be monitored prospectively by using serum markers, together with TVUS imaging, to detect early-stage OVCA, provided that a panel of serum markers can be established and imaging agents developed. Recent sequencing of the chicken genome will further facilitate the hen model to explore gene therapies against OVCA.

Endothelial p130cas confers resistance to anti-angiogenesis therapy

Anti-angiogenic therapies, such as anti-VEGF antibodies (AVAs), have shown promise in clinical settings. However, adaptive resistance to such therapies occurs frequently. We use orthotopic ovarian cancer models with AVA-adaptive resistance to investigate the underlying mechanisms. Genomic profiling of AVA-resistant tumors guides us to endothelial p130cas. We find that bevacizumab induces cleavage of VEGFR2 in endothelial cells by caspase-10 and that VEGFR2 fragments internalize into the nucleus and autophagosomes. Nuclear VEGFR2 and p130cas fragments, together with TNKS1BP1 (tankyrase-1-binding protein), initiate endothelial cell death. Blockade of autophagy in AVA-resistant endothelial cells retains VEGFR2 at the membrane with bevacizumab treatment. Targeting host p130cas with RGD (Arg-Gly-Asp)-tagged nanoparticles or genomic ablation of vascular p130cas in p130casflox/floxTie2Cre mice significantly extends the survival of mice with AVA-resistant ovarian tumors. Higher vascular p130cas is associated with shorter survival of individuals with ovarian cancer. Our findings identify opportunities for new strategies to overcome adaptive resistance to AVA therapy.

Multiomic analysis identifies CPT1A as a potential therapeutic target in platinum-refractory, high-grade serous ovarian cancer

Resistance to platinum compounds is a major determinant of patient survival in high-grade serous ovarian cancer (HGSOC). To understand mechanisms of platinum resistance and identify potential therapeutic targets in resistant HGSOC, we generated a data resource composed of dynamic (±carboplatin) protein, post-translational modification, and RNA sequencing (RNA-seq) profiles from intra-patient cell line pairs derived from 3 HGSOC patients before and after acquiring platinum resistance. These profiles reveal extensive responses to carboplatin that differ between sensitive and resistant cells. Higher fatty acid oxidation (FAO) pathway expression is associated with platinum resistance, and both pharmacologic inhibition and CRISPR knockout of carnitine palmitoyltransferase 1A (CPT1A), which represents a rate limiting step of FAO, sensitize HGSOC cells to platinum. The results are further validated in patient-derived xenograft models, indicating that CPT1A is a candidate therapeutic target to overcome platinum resistance. All multiomic data can be queried via an intuitive gene-query user interface (https://sites.google.com/view/ptrc-cell-line).

LYVE1+ macrophages of murine peritoneal mesothelium promote omentum-independent ovarian tumor growth

Two resident macrophage subsets reside in peritoneal fluid. Macrophages also reside within mesothelial membranes lining the peritoneal cavity, but they remain poorly characterized. Here, we identified two macrophage populations (LYVE1hi MHC IIlo-hi CX3CR1gfplo/- and LYVE1lo/- MHC IIhi CX3CR1gfphi subsets) in the mesenteric and parietal mesothelial linings of the peritoneum. These macrophages resembled LYVE1+ macrophages within surface membranes of numerous organs. Fate-mapping approaches and analysis of newborn mice showed that LYVE1hi macrophages predominantly originated from embryonic-derived progenitors and were controlled by CSF1 made by Wt1+ stromal cells. Their gene expression profile closely overlapped with ovarian tumor-associated macrophages previously described in the omentum. Indeed, syngeneic epithelial ovarian tumor growth was strongly reduced following in vivo ablation of LYVE1hi macrophages, including in mice that received omentectomy to dissociate the role from omental macrophages. These data reveal that the peritoneal compartment contains at least four resident macrophage populations and that LYVE1hi mesothelial macrophages drive tumor growth independently of the omentum.

Personalized models of heterogeneous 3D epithelial tumor microenvironments: Ovarian cancer as a model

Intractable human diseases such as cancers, are context dependent, unique to both the individual patient and to the specific tumor microenvironment. However, conventional cancer treatments are often nonspecific, targeting global similarities rather than unique drivers. This limits treatment efficacy across heterogeneous patient populations and even at different tumor locations within the same patient. Ultimately, this poor efficacy can lead to adverse clinical outcomes and the development of treatment-resistant relapse. To prevent this and improve outcomes, it is necessary to be selective when choosing a patient's optimal adjuvant treatment. In this review, we posit the use of personalized, tumor-specific models (TSM) as tools to achieve this remarkable feat. First, using ovarian cancer as a model disease, we outline the heterogeneity and complexity of both the cellular and extracellular components in the tumor microenvironment. Then we examine the advantages and disadvantages of contemporary cancer models and the rationale for personalized TSM. We discuss how to generate precision 3D models through careful and detailed analysis of patient biopsies. Finally, we provide clinically relevant applications of these versatile personalized cancer models to highlight their potential impact. These models are ideal for a myriad of fundamental cancer biology and translational studies. Importantly, these approaches can be extended to other carcinomas, facilitating the discovery of new therapeutics that more effectively target the unique aspects of each individual patient's TME. STATEMENT OF SIGNIFICANCE: In this article, we have presented the case for the application of biomaterials in developing personalized models of complex diseases such as cancers. TSM could bring about breakthroughs in the promise of precision medicine. The critical components of the diverse tumor microenvironments, that lead to treatment failures, include cellular- and extracellular matrix- heterogeneity, and biophysical signals to the cells. Therefore, we have described these dynamic components of the tumor microenvironments, and have highlighted how contemporary biomaterials can be utilized to create personalized in vitro models of cancers. We have also described the application of the TSM to predict the dynamic patterns of disease progression, and predict effective therapies that can produce durable responses, limit relapses, and treat any minimal residual disease.

Inactivation of TRP53, PTEN, RB1, and/or CDH1 in the ovarian surface epithelium induces ovarian cancer transformation and metastasis

Ovarian cancer (OvCa) remains the most common cause of death from gynecological malignancies. Genetically engineered mouse models have been used to study initiation, origin, progression, and/or mechanisms of OvCa. Based on the clinical features of OvCa, we examined a quadruple combination of pathway perturbations including PTEN, TRP53, RB1, and/or CDH1. To characterize the cancer-promoting events in the ovarian surface epithelium (OSE), Amhr2cre/+ mice were used to ablate floxed alleles of Pten, Trp53, and Cdh1, which were crossed with TgK19GT121 mice to inactivate RB1 in KRT19-expressing cells. Inactivation of PTEN, TRP53, and RB1 with or without CDH1 led to the development of type I low-grade OvCa with enlarged serous papillary carcinomas and some high-grade serous carcinomas (HGSCs) in older mice. Initiation of epithelial hyperplasia and micropapillary carcinoma started earlier at 1 month in the triple mutations of Trp53, Pten, and Rb1 mice as compared to 2 months in quadruple mutations of Trp53, Pten, Rb1, and Cdh1 mice, whereas both genotypes eventually developed enlarged proliferating tumors that invaded into the ovary at 3-4 months. Mice with triple and quadruple mutations developed HGSC and/or metastatic tumors, which disseminated into the peritoneal cavity at 4-6 months. In summary, inactivation of PTEN, TRP53, and RB1 initiates OvCa from the OSE. Additional ablation of CDH1 further increased persistence of tumor dissemination and ascites fluid accumulation enhancing peritoneal metastasis.

Comprehensive Analysis of Prognostic Value of MEX3A and Its Relationship with Immune Infiltrates in Ovarian Cancer

MEX3A is a critical RNA-binding ubiquitin ligase that is upregulated in various types of cancer. However, the correlations of MEX3A with prognosis and its molecular mechanism in ovarian cancer (OC) remain unclear. The expression level, prognostic values, and the genetic variations of MEX3A were analyzed via Gene Expression Profiling Interactive Analysis (GEPIA) Oncomine, Kaplan-Meier plotter, and cBioPortal. We used the LinkedOmics database to investigate the functions of MEX3A coexpressed genes and performed visualizing gene interaction network analysis on the GeneMANIA website. The correlations between MEX3A and cancer immune infiltration were analyzed by the Tumor Immune Estimation Resource (TIMER) site and the TISIDB database. Furthermore, in vitro analysis was performed to evaluate the biological functions of MEX3A in OC cells. Our study showed that the expression of the MEX3A in OC was higher than in normal tissues; it had the greatest prognostic value in OC, and strong physical interaction with PABPC1, LAMTOR2, KHDRBS2, and IGF2BP2, which indicated the association between MEX3A and immune infiltration. We also found that MEX3A was negatively related to infiltrating levels of several types of immune cells, including macrophages, neutrophils, dendritic cells (DCs), B cells, and CD8+ T cells. Additionally, in vitro experiments demonstrated that MEX3A promotes proliferation and migration in OC cells. Taken together, MEX3A might influence the biological functions of OC cells by regulating the immune infiltration in the microenvironment as a prognostic biomarker and a potential therapeutic target.

Serotonin/HTR1E signaling blocks chronic stress-promoted progression of ovarian cancer

Rationale: Psychological stress has been linked to cancer development and resistance to therapy by many epidemiological and clinical studies. Stress-induced immunosuppressive microenvironment by stress hormones, in particular glucocorticoids, has been extensively studied. However, the impacts of other stress-related neurotransmitters, such as serotonin (5-hydroxytryptamine, 5-HT), on cancer development just start to be revealed. Here, we aimed to identify novel neurotransmitters involved in stress-induced growth and dissemination of ovarian cancer (OC) and reveal the major underlying signaling pathway and the therapeutic significance. Methods: Through a genome-wide CRISPR/Cas9 knockout screen in the murine orthotopic model of ovarian carcinoma (OC), we identified candidate genes regulating the peritoneal dissemination of OC. Among them, we picked out HTR1E, one member of 5-HT receptor family specifically expressed in the ovary and endometrium in addition to brain. The correlation of HTR1E expression with OC progression was analyzed in OC patient specimen by quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot, and immunohistochemistry (IHC). Gain-of-function and loss-of-function analyses were performed to explore the functions of 5-HT/HTR1E signaling in OC growth and dissemination in vitro and in vivo. In addition, we investigated the therapeutic values of HTR1E specific agonist and small molecular inhibitors against HTR1E downstream factor SRC in a stressed murine OC xenograft model. Results: In OC patients, the HTR1E expression is dramatically decreased in peritoneal disseminated OC cells, which correlates with poor clinical outcome. Silence of HTR1E in OC cells greatly promotes cell proliferation and epithelial mesenchymal transition (EMT) by the activation of SRC-mediated downstream signaling pathways. Furthermore, chronic stress results in significantly decreased serotonin in the ovary and the enhanced OC growth and peritoneal dissemination in mice, which can be strongly inhibited by specific HTR1E agonist or the SRC inhibitor. Conclusions: We discovered the essential role of serotonin/HTR1E signaling in preventing the chronic psychological stress-promoted progression of OC, suggesting the potential therapeutic value of the HTR1E specific agonist and the SRC inhibitor for OC patients who are suffering from psychological stress.

Metalloproteinases in Ovarian Cancer

Proteases play a crucial role in the progression and metastasis of ovarian cancer. Pericellular protein degradation and fragmentation along with remodeling of the extracellular matrix (ECM) is accomplished by numerous proteases that are present in the ovarian tumor microenvironment. Several proteolytic processes have been linked to cancer progression, particularly those facilitated by the matrix metalloproteinase (MMP) family. These proteases have been linked to enhanced migratory ability, extracellular matrix breakdown, and development of support systems for tumors. Several studies have reported the direct involvement of MMPs with ovarian cancer, as well as their mechanisms of action in the tumor microenvironment. MMPs play a key role in upregulating transcription factors, as well as the breakdown of structural proteins like collagen. Proteolytic mechanisms have been shown to enhance the ability of ovarian cancer cells to migrate and adhere to secondary sites allowing for efficient metastasis. Furthermore, angiogenesis for tumor growth and development of metastatic implants is influenced by upregulation of certain proteases, including MMPs. While proteases are produced normally in vivo, they can be upregulated by cancer-associated mutations, tumor-microenvironment interaction, stress-induced catecholamine production, and age-related pathologies. This review outlines the important role of proteases throughout ovarian cancer progression and metastasis.

Mouse models of epithelial ovarian cancer for preclinical studies

Epithelial ovarian cancer (EOC) is the leading cause of gynecological cancer-related mortality in the developed world. EOC is a heterogeneous disease represented by several histological and molecular subtypes. Therefore, exploration of relevant preclinical animal models that consider the heterogenic nature of EOC is of great importance for the development of novel therapeutic strategies that can be translated clinically to combat this devastating disease. In this review, we discuss recent progress in the development of preclinical mouse models for EOC study as well as their advantages and limitations.

Small extracellular vesicles ameliorate peripheral neuropathy and enhance chemotherapy of oxaliplatin on ovarian cancer

There are no effective treatments for chemotherapy induced peripheral neuropathy (CIPN). Small extracellular vesicles (sEVs) facilitate intercellular communication and mediate nerve function and tumour progression. We found that the treatment of mice bearing ovarian tumour with sEVs derived from cerebral endothelial cells (CEC-sEVs) in combination with a chemo-drug, oxaliplatin, robustly reduced oxaliplatin-induced CIPN by decreasing oxaliplatin-damaged myelination and nerve fibres of the sciatic nerve and significantly amplified chemotherapy of oxaliplatin by reducing tumour size. The combination therapy substantially increased a set of sEV cargo-enriched miRNAs, but significantly reduced oxaliplatin-increased proteins in the sciatic nerve and tumour tissues. Bioinformatics analysis revealed the altered miRNAs and proteins formed two distinct networks that regulate neuropathy and tumour growth, respectively. Intravenously administered CEC-sEVs were internalized by axons of the sciatic nerve and cancer cells. Reduction of CEC-sEV cargo miRNAs abolished the effects of CEC-sEVs on oxaliplatin-inhibited axonal growth and on amplification of the anti-cancer effect in ovarian cancer cells, suggesting that alterations in the networks of miRNAs and proteins in recipient cells contribute to the therapeutic effect of CEC-sEVs on CIPN. Together, the present study demonstrates that CEC-sEVs suppressed CIPN and enhanced chemotherapy of oxaliplatin in the mouse bearing ovarian tumour.

MiR-200c-3p Contrasts PD-L1 Induction by Combinatorial Therapies and Slows Proliferation of Epithelial Ovarian Cancer through Downregulation of β-Catenin and c-Myc

Conventional/targeted chemotherapies and ionizing radiation (IR) are being used both as monotherapies and in combination for the treatment of epithelial ovarian cancer (EOC). Several studies show that these therapies might favor oncogenic signaling and impede anti-tumor responses. MiR-200c is considered a master regulator of EOC-related oncogenes. In this study, we sought to investigate if chemotherapy and IR could influence the expression of miR-200c-3p and its target genes, like the immune checkpoint PD-L1 and other oncogenes in a cohort of EOC patients’ biopsies. Indeed, PD-L1 expression was induced, while miR-200c-3p was significantly reduced in these biopsies post-therapy. The effect of miR-200c-3p target genes was assessed in miR-200c transfected SKOV3 cells untreated and treated with olaparib and IR alone. Under all experimental conditions, miR-200c-3p concomitantly reduced PD-L1, c-Myc and β-catenin expression and sensitized ovarian cancer cells to olaparib and irradiation. In silico analyses further confirmed the anti-correlation between miR-200c-3p with c-Myc and β-catenin in 46 OC cell lines and showed that a higher miR-200c-3p expression associates with a less tumorigenic microenvironment. These findings provide new insights into how miR-200c-3p could be used to hold in check the adverse effects of conventional chemotherapy, targeted therapy and radiation therapy, and offer a novel therapeutic strategy for EOC.

Nanog-mediated stem cell properties is critical for MBNL3 associated paclitaxel resistance of ovarian cancer

Paclitaxel (PTX) is the standard first-line treatment of ovarian cancer, but its efficacy is limited by multi-drug resistance. Therefore, it is crucial to identify effective drug targets to facilitate PTX-sensitivity for ovarian cancer treatment. Seventy PTX-administrated ovarian cancer patients were recruited in this study for gene expression and survival rate analyses. Muscleblind-like-3 (MBNL3) gain- and loss-of-function experiments were carried out in ovarian cancer cells (parental and PTX-resistant) and xenograft model. Cancer cell viability, apoptosis, spheroids formation, Nanog gene silencing were examined and conducted to dissect the underlying mechanism of MBNL3-mediated PTX-resistance. High expression of MBNL3 was positively correlated with PTX-resistance and poor prognosis of ovarian cancer. MBNL3 increased cell viability and decreased apoptosis in ovarian stem-like cells, through up-regulating Nanog. This study suggests the MBNL3-Nanog axis is a therapeutic target for the treatment of PTX-resistance in ovarian cancer management.

In vivo selection of highly metastatic human ovarian cancer sublines reveals role for AMIGO2 in intra-peritoneal metastatic regulation

The majority of women with ovarian cancer are diagnosed with metastatic disease, therefore elucidating molecular events that contribute to successful metastatic dissemination may identify additional targets for therapeutic intervention and thereby positively impact survival. Using two human high grade serous ovarian cancer cell lines with inactive TP53 and multiple rounds of serial in vivo passaging, we generated sublines with significantly accelerated intra-peritoneal (IP) growth. Comparative analysis of the parental and IP sublines identified a common panel of differentially expressed genes. The most highly differentially expressed gene, upregulated by 60-65-fold in IP-selected sublines, was the type I transmembrane protein AMIGO2. As the role of AMIGO2 in ovarian cancer metastasis remains unexplored, CRISPR/Cas9 was used to reduce AMIGO2 expression, followed by in vitro and in vivo functional analyses. Knockdown of AMIGO2 modified the sphere-forming potential of ovarian cancer cells, reduced adhesion and invasion in vitro, and significantly attenuated IP metastasis. These data highlight AMIGO2 as a new target for a novel anti-metastatic therapeutic approach aimed at blocking cohesion, survival, and adhesion of metastatic tumorspheres.

3D Models for Ovarian Cancer

The main reasons for the slow progress in improving survival outcomes for ovarian cancer are the 'one-size-fits-all' therapy and lack of clinically relevant experimental models that represent the advanced stages of the human disease. The interaction of tumour cells with their surrounding niche, the tumour microenvironment, influences the spread of ovarian cancer cells within the peritoneum and their responses to therapeutics. Scientists are increasingly using 3D cell culture models to dissect the role of the tumour microenvironment in cancer development and progression and the treatment of this disease. In this chapter, we will briefly describe the tumour microenvironment of ovarian cancer. Then, we will review some of the clinically relevant experimental approaches, such as spheroid, organoid and organotypic models, that have been developed for the 3D culture of ovarian cancer cells using different tools, including hydrogels, scaffolds and cancer-on-a-chip devices, to mimic selected components of the tumour microenvironment.

Exploring the Potential of Drug Response Assays for Precision Medicine in Ovarian Cancer

One of the major challenges in the treatment of cancer are differential responses of patients to existing standard of care anti-cancer drugs. These differential responses may, in part, be due to a diverse range of genomic, epigenomic, proteomic, and metabolic alterations among individuals suffering from the same type of cancer. Precision medicine is an emerging approach in cancer therapeutics that takes into account specific molecular alterations, environmental factors as well as lifestyle of individual patients. This approach allows clinicians and researchers to select or predict treatments that would most likely benefit the patient based on their individual tumor characteristics. One class of precision medicine tools are predictive, in vitro drug-response assays designed to test the sensitivity of patient tumor cells to existing or novel therapies. These assays have the potential to rapidly identify the most effective treatments for cancer patients and thus hold great promise in the field of precision medicine. In this review, we have highlighted several drug-response assays developed in ovarian cancer and discussed the current challenges and future prospects of these assays in the clinical management of this disease.

Modular Peptide Probe for Pre/Intra/Postoperative Therapeutic to Reduce Recurrence in Ovarian Cancer

Even with optimal surgery, 80% of patients with ovarian cancer will have recurrence. Adjuvant therapy can reduce the recurrence of tumors; however, the therapeutic effect is still not prominent. Herein, we designed a modular peptide probe (T_CDTMP), which can be self-assembled into nanoparticles (NPs) by loading in miR-145-5p or VEGF-siRNA. In vivo, (1) preoperative administration of T_CDTMP/miR-145-5p ensured that NPs were adequately accumulated in tumors through active targeting and increased the expression of miR-145-5p in tumors, thereby inducing tumor cell apoptosis. (2) Intraoperatively, most of the tumors were removed, while the microscopic residual tumors were largely eliminated by T_CDTMP/miR-145-5p-mediated photodynamic therapy (PDT). (3) Postoperatively, T_CDTMP/VEGF-siRNA were given for antiangiogenesis therapy, thus delaying the recurrence of tumors. This treatment was named a preoperative (T_CDTMP/miR-145-5p)||intraoperative (surgery and PDT)||postoperative (T_CDTMP/VEGF-siRNA) therapeutic system and abbreviated as the PIP therapeutic system, which reduced the recurrence of ovarian cancer in subcutaneous tumor models, intraperitoneal metastasis models, and patient-derived tumor xenograft models. Our findings provide a therapeutic system based on modular peptide probes to reduce the recurrence of ovarian cancer after surgery, which provides a perspective for the surgical management of ovarian cancer.

Lassa-VSV chimeric virus targets and destroys human and mouse ovarian cancer by direct oncolytic action and by initiating an anti-tumor response

Ovarian cancer is the third most common female cancer, with poor survival in later stages of metastatic spread. We test a chimeric virus consisting of genes from Lassa and vesicular stomatitis viruses, LASV-VSV; the native VSV glycoprotein is replaced by the Lassa glycoprotein, greatly reducing neurotropism. Human ovarian cancer cells in immunocompromised nude mice were lethal in controls. Chemotherapeutic paclitaxel and cisplatin showed modest cancer inhibition and survival extension. In contrast, a single intraperitoneal injection of LASV-VSV selectively infected and killed ovarian cancer cells, generating long-term survival. Mice with human ovarian cancer cells in brain showed rapid deterioration; LASV-VSV microinjection into brain blocked cancer growth, and generated long-term survival. Treatment of immunocompetent mice with infected mouse ovarian cancer cells blocked growth of non-infected ovarian cancer cells peritoneally and in brain. These results suggest LASV-VSV is a viable candidate for further study and may be of use in the treatment of ovarian cancer.

Patient-derived ovarian cancer explants: preserved viability and histopathological features in long-term agitation-based cultures

Ovarian carcinoma (OvC) remains a major therapeutic challenge due to its propensity to develop resistance after an initial response to chemotherapy. Interactions of tumour cells with the surrounding microenvironment play a role in tumour survival, invasion capacity and drug resistance. Cancer models that retain tissue architecture and tumour microenvironment components are therefore essential to understand drug response and resistance mechanisms. Herein, our goal was to develop a long-term OvC patient-derived explant (OvC-PDE) culture strategy in which architecture and cell type heterogeneity of the original tumour would be retained. Samples from 25 patients with distinct OvC types and one with a benign tumour, were cultured for 30 days in agitation-based culture systems with 100% success rate. OvC-PDE cultures retained the original tumour architecture and main cellular components: epithelial cells, fibroblasts and immune cells. Epithelial cells kept their original levels of proliferation and apoptosis. Moreover, the major extracellular components, such as collagen-I and -IV, were retained in explants. OvC-PDE cultures were exposed to standard-of-care chemotherapeutics agents for 2 weeks, attesting the ability of the platform for drug assays employing cyclic drug exposure regimens. We established an OvC-PDE dynamic culture in which tumour architecture and cell type heterogeneity were preserved for the different OvC types, replicating features of the original tumour and compatible with long-term drug exposure for drug efficacy and resistance studies.

High-throughput approaches for precision medicine in high-grade serous ovarian cancer

High-grade serous carcinoma (HGSC) is the most prevalent and aggressive subtype of ovarian cancer. The large degree of clinical heterogeneity within HGSC has justified deviations from the traditional one-size-fits-all clinical management approach. However, the majority of HGSC patients still relapse with chemo-resistant cancer and eventually succumb to their disease, evidence that further work is needed to improve patient outcomes. Advancements in high-throughput technologies have enabled novel insights into biological complexity, offering a large potential for informing precision medicine efforts. Here, we review the current landscape of clinical management for HGSC and highlight applications of high-throughput biological approaches for molecular subtyping and the discovery of putative blood-based biomarkers and novel therapeutic targets. Additionally, we present recent improvements in model systems and discuss how their intersection with high-throughput platforms and technological advancements is positioned to accelerate the realization of precision medicine in HGSC.

Ascites-induced compression alters the peritoneal microenvironment and promotes metastatic success in ovarian cancer

The majority of women with recurrent ovarian cancer (OvCa) develop malignant ascites with volumes that can reach > 2 L. The resulting elevation in intraperitoneal pressure (IPP), from normal values of 5 mmHg to as high as 22 mmHg, causes striking changes in the loading environment in the peritoneal cavity. The effect of ascites-induced changes in IPP on OvCa progression is largely unknown. Herein we model the functional consequences of ascites-induced compression on ovarian tumor cells and components of the peritoneal microenvironment using a panel of in vitro, ex vivo and in vivo assays. Results show that OvCa cell adhesion to the peritoneum was increased under compression. Moreover, compressive loads stimulated remodeling of peritoneal mesothelial cell surface ultrastructure via induction of tunneling nanotubes (TNT). TNT-mediated interaction between peritoneal mesothelial cells and OvCa cells was enhanced under compression and was accompanied by transport of mitochondria from mesothelial cells to OvCa cells. Additionally, peritoneal collagen fibers adopted a more linear anisotropic alignment under compression, a collagen signature commonly correlated with enhanced invasion in solid tumors. Collectively, these findings elucidate a new role for ascites-induced compression in promoting metastatic OvCa progression.

Lysophosphatidic acid modulates ovarian cancer multicellular aggregate assembly and metastatic dissemination

Epithelial ovarian cancer (EOC) metastasis occurs by exfoliation of cells and multicellular aggregates (MCAs) from the tumor into the peritoneal cavity, adhesion to and retraction of peritoneal mesothelial cells and subsequent anchoring. Elevated levels of lysophosphatidic acid (LPA) have been linked to aberrant cell proliferation, oncogenesis, and metastasis. LPA disrupts junctional integrity and epithelial cohesion in vitro however, the fate of free-floating cells/MCAs and the response of host peritoneal tissues to LPA remain unclear. EOC MCAs displayed significant LPA-induced changes in surface ultrastructure with the loss of cell surface protrusions and poor aggregation, resulting in increased dissemination of small clusters compared to untreated control MCAs. LPA also diminished the adhesive capacity of EOC single cells and MCAs to murine peritoneal explants and impaired MCA survival and mesothelial clearance competence. Peritoneal tissues from healthy mice injected with LPA exhibited enhanced mesothelial surface microvilli. Ultrastructural alterations were associated with restricted peritoneal susceptibility to metastatic colonization by single cells as well as epithelial-type MCAs. The functional consequence is an LPA-induced dissemination of small mesenchymal-type clusters, promoting a miliary mode of peritoneal seeding that complicates surgical removal and is associated with worse prognosis.

SUSD2 expression correlates with decreased metastasis and increased survival in a high-grade serous ovarian cancer xenograft murine model

The cause of death among high-grade serous ovarian cancer (HGSOC) patients involves passive dissemination of cancer cells within the peritoneal cavity and subsequent implantation of cancer spheroids into adjacent organs. Sushi DomainContaining 2 (SUSD2) encodes a type I transmembrane protein containing several functional domains inherent to adhesion molecules. Previous studies using in vitro methods have indicated that SUSD2 functions as a tumor suppressor in several cancers, including HGSOC. In this study, we generated a HGSOC xenograft mouse model to investigate SUSD2 expression in the context of HGSOC late-stage metastasis and overall survival. OVCAR3 cells with knock-down expression of SUSD2 (OVCAR3 SUSD2-KD) or endogenous expression of SUSD2 (OVCAR3-Non-Targeting (NT)) were injected into the peritoneal cavity of athymic nude mice. Immunohistochemistry analysis was utilized to identify infiltrating cancer cells and metastatic tumors in mouse ovaries, pancreas, spleen, omentum and liver. OVCAR3-NT mice developed significantly less cancer cell infiltrate and tumors in their pancreas and omentum compared to OVCAR3 SUSD2-KD mice. Furthermore, OVCAR3-NT mice displayed a longer median survival when compared to OVCAR3 SUSD2-KD mice (175 days and 185.5 days, respectively; p-value 0.0159). Altogether, the findings generated through the preclinical mouse model suggest that increased SUSD2 expression in HGSOC impedes in vivo metastasis to pancreas and omentum. These results correlate to longer median survival and prove to be consistent with previous findings showing prolonged survival of HGSOC patients with high SUSD2-expressing primary tumors.

Chemotherapy exacerbates ovarian cancer cell migration and cancer stem cell-like characteristics through GLI1

BACKGROUND

Despite the great clinical response to the first-line chemotherapeutics, metastasis still happens among most of the ovarian cancer patients within 2 years.

METHODS

Using multiple human ovarian cancer cell lines, a transwell co-culture system of the carboplatin or VP-16-challenged feeder and receptor cells was established to demonstrate the chemotherapy-exacerbated migration. The migration and cancer stem cell (CSC)-like characteristics were determined by wound healing, transwell migration, flow cytometry and sphere formation. mRNA and protein expression were identified by qPCR and western blot. Bioinformatics analysis was used to investigate the differentially expressed genes. GLI1 expression in tissue samples was analysed by immunohistochemistry.

RESULTS

Chemotherapy was found to not only kill tumour cells, but also trigger the induction of CSC-like traits and the migration of ovarian cancer cells. EMT markers Vimentin and Snail in receptor cells were upregulated in the microenvironment of chemotherapy-challenged feeder cells. The transcription factor GLI1 was upregulated by chemotherapy in both clinical samples and cell lines. Follow-up functional experiments illustrated that inhibiting GLI1 reversed the chemotherapy-exacerbated CSC-like traits, including CD44 and CD133, as well as prevented the migration of ovarian cancer cells.

CONCLUSIONS

Targeting GLI1 may improve clinical benefits in the chemotherapy-exacerbated metastasis in ovarian cancer treatment.

A novel role for NUAK1 in promoting ovarian cancer metastasis through regulation of fibronectin production in spheroids

Epithelial ovarian cancer (EOC) has a unique mode of metastasis, where cells shed from the primary tumour, form aggregates called spheroids to evade anoikis, spread through the peritoneal cavity, and adhere to secondary sites. We previously showed that the master kinase Liver kinase B1 (LKB1) is required for EOC spheroid viability and metastasis. We have identified novel (nua) kinase 1 (NUAK1) as a top candidate LKB1 substrate in EOC cells and spheroids using a multiplex inhibitor beads-mass spectrometry approach. We confirmed that LKB1 maintains NUAK1 phosphorylation and promotes its stabilization. We next investigated NUAK1 function in EOC cells. Ectopic NUAK1-overexpressing EOC cell lines had increased adhesion, whereas the reverse was seen in OVCAR8-NUAK1KO cells. In fact, cells with NUAK1 loss generate spheroids with reduced integrity, leading to increased cell death after long-term culture. Following transcriptome analysis, we identified reduced enrichment for cell interaction gene expression pathways in OVCAR8-NUAK1KO spheroids. In fact, the FN1 gene, encoding fibronectin, exhibited a 745-fold decreased expression in NUAK1KO spheroids. Fibronectin expression was induced during native spheroid formation, yet this was completely lost in NUAK1KO spheroids. Co-incubation with soluble fibronectin restored the compact spheroid phenotype to OVCAR8-NUAK1KO cells. In a xenograft model of intraperitoneal metastasis, NUAK1 loss extended survival and reduced fibronectin expression in tumours. Thus, we have identified a new mechanism controlling EOC metastasis, through which LKB1-NUAK1 activity promotes spheroid formation and secondary tumours via fibronectin production.

Isoquinolinequinone N-oxides as anticancer agents effective against drug resistant cell lines

The isoquinolinequinone (IQQ) pharmacophore is a privileged framework in known cytotoxic natural product families, caulibugulones and mansouramycins. Exploiting both families as a chemical starting point, we report on the structured development of an IQQ N-oxide anticancer framework which exhibits growth inhibition in the nM range across melanoma, ovarian and leukaemia cancer cell lines. A new lead compound (16, R6 = benzyl, R7 = H) exhibits nM GI50 values against 31/57 human tumour cell lines screened as part of the NCI60 panel and shows activity against doxorubicin resistant tumour cell lines. An electrochemical study highlights a correlation between electropositivity of the IQQ N-oxide framework and cytotoxicity. Adduct binding to sulfur based biological nucleophiles glutathione and cysteine was observed in vitro. This new framework possesses significant anticancer potential.

Use of Transabdominal Ultrasound for the detection of intra-peritoneal tumor engraftment and growth in mouse xenografts of epithelial ovarian cancer

OBJECTIVE

To evaluate intraperitoneal (IP) tumor engraftment, metastasis and growth in a pre-clinical murine epithelial ovarian cancer (EOC) model using both transabdominal ultrasound (TAUS) and bioluminescence in vivo imaging system (IVIS).

METHODS

Ten female C57Bl/6J mice at six weeks of age were included in this study. Five mice underwent IP injection of 5x106 ID8-luc cells (+ D- luciferin) and the remaining five mice underwent IP injection of ID8-VEGF cells. Monitoring of tumor growth and ascites was performed weekly starting at seven days post-injection until study endpoint. ID8-luc mice were monitored using both TAUS and IVIS, and ID8-VEGF mice underwent TAUS monitoring only. Individual tumor implant dimension and total tumor volume were calculated. Average luminescent intensity was calculated and reported per mouse abdomen. Tumor detection was confirmed by gross evaluation and histopathology. All data are presented as mean +/- standard deviation.

RESULTS

Overall, tumors were successfully detected in all ten mice using TAUS and IVIS, and tumor detection correlated with terminal endpoint histology/ H&E staining. For TAUS, the smallest confirmed tumor measurements were at seven days post-injection with mean long axis of 2.23mm and mean tumor volume of 4.17mm3. However, IVIS imaging was able to detect tumor growth at 14 days post-injection. Ascites formation was detected in mice at 21 days post-injection.

CONCLUSIONS

TAUS is highly discriminatory for monitoring EOC in pre-clinical murine model, allowing for detection of tumor dimension as small as 2 mm and as early as seven days post-injection compared to IVIS. In addition, TAUS provides relevant information for ascites development and detection of multiple small metastatic tumor implants. TAUS provides an accurate and reliable method to detect and monitor IP EOC growth in mouse xenografts.

Developing Organoids from Ovarian Cancer as Experimental and Preclinical Models

Ovarian cancer (OC) represents the most dismal gynecological cancer. Pathobiology is poorly understood, mainly due to lack of appropriate study models. Organoids, defined as self-developing three-dimensional in vitro reconstructions of tissues, provide powerful tools to model human diseases. Here, we established organoid cultures from patient-derived OC, in particular from the most prevalent high-grade serous OC (HGSOC). Testing multiple culture medium components identified neuregulin-1 (NRG1) as key factor in maximizing OC organoid development and growth, although overall derivation efficiency remained moderate (36% for HGSOC patients, 44% for all patients together). Established organoid lines showed patient tumor-dependent morphology and disease characteristics, and recapitulated the parent tumor's marker expression and mutational landscape. Moreover, the organoids displayed tumor-specific sensitivity to clinical HGSOC chemotherapeutic drugs. Patient-derived OC organoids provide powerful tools for the study of the cancer's pathobiology (such as importance of the NRG1/ERBB pathway) as well as advanced preclinical tools for (personalized) drug screening and discovery.

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Organoids are established from ovarian cancer (OC)

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Neuregulin-1 (NRG1) is identified as key component for OC organoid growth

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OC organoids capture disease hallmarks and recapitulate patient tumor characteristics

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OC organoids are amenable to drug screening and mechanistic (NRG1/ERBB) research

The microbiome and gynaecological cancer development, prevention and therapy

The female reproductive tract (FRT), similar to other mucosal sites, harbours a site-specific microbiome, which has an essential role in maintaining health and homeostasis. In the majority of women of reproductive age, the microbiota of the lower FRT (vagina and cervix) microenvironment is dominated by Lactobacillus species, which benefit the host through symbiotic relationships. By contrast, the upper FRT (uterus, Fallopian tubes and ovaries) might be sterile in healthy individuals or contain a low-biomass microbiome with a diverse mixture of microorganisms. When dysbiosis occurs, altered immune and metabolic signalling can affect hallmarks of cancer, including chronic inflammation, epithelial barrier breach, changes in cellular proliferation and apoptosis, genome instability, angiogenesis and metabolic dysregulation. These pathophysiological changes might lead to gynaecological cancer. Emerging evidence shows that genital dysbiosis and/or specific bacteria might have an active role in the development and/or progression and metastasis of gynaecological malignancies, such as cervical, endometrial and ovarian cancers, through direct and indirect mechanisms, including modulation of oestrogen metabolism. Cancer therapies might also alter microbiota at sites throughout the body. Reciprocally, microbiota composition can influence the efficacy and toxic effects of cancer therapies, as well as quality of life following cancer treatment. Modulation of the microbiome via probiotics or microbiota transplant might prove useful in improving responsiveness to cancer treatment and quality of life. Elucidating these complex host-microbiome interactions, including the crosstalk between distal and local sites, will translate into interventions for prevention, therapeutic efficacy and toxic effects to enhance health outcomes for women with gynaecological cancers.

Exploring cisplatin resistance in ovarian cancer through integrated bioinformatics approach and overcoming chemoresistance with sanguinarine

Ovarian cancer is refractory in response towards platinum-based chemotherapy, and resistance frequently develops. We attempted to identify the driving pathways in cisplatin-resistant ovarian cancer and develop targeted therapies to overcome this resistance. Using an integrated bioinformatics approach, a GSE15372 database from NCBI's Gene Expression Omnibus database was obtained for identifying differentially expressed genes (DEGs), in which 535 DEGs were found (407 up-regulated and 128 down-regulated) in association with ovarian cancer cisplatin-resistance. Gene ontology and pathway enrichment analyses further found that aberrant activation of EGFR/ErbB2 signaling was the driving event in resistant cells. A network of dysregulated genes was built based on these identified DEGs and protein-protein interaction network, which led to the identification of 7 potential inhibitors based on screening a 77 small molecule natural product library. Sanguinarine, alone and in combination with cisplatin, was found to significantly suppress the proliferation of wt/resistant ovarian cancer cells in vitro and the growth of parental and resistant ovarian xenograft tumors in vivo. Our study suggests that EGFR/ErbB2 activation is one of the driving pathways in developing cisplatin-resistance in ovarian cancer, and that sanguinarine has the potential to be developed as an effective therapy to overcome this therapeutic resistance.