The heterogeneity of ovarian cancer

Paradigm Shift: A Comprehensive Review of Ovarian Cancer Management in an Era of Advancements

Ovarian cancer (OC) is the female genital malignancy with the highest lethality. Patients present a poor prognosis mainly due to the late clinical presentation allied with the common acquisition of chemoresistance and a high rate of tumour recurrence. Effective screening, accurate diagnosis, and personalised multidisciplinary treatments are crucial for improving patients' survival and quality of life. This comprehensive narrative review aims to describe the current knowledge on the aetiology, prevention, diagnosis, and treatment of OC, highlighting the latest significant advancements and future directions. Traditionally, OC treatment involves the combination of cytoreductive surgery and platinum-based chemotherapy. Although more therapeutical approaches have been developed, the lack of established predictive biomarkers to guide disease management has led to only marginal improvements in progression-free survival (PFS) while patients face an increasing level of toxicity. Fortunately, because of a better overall understanding of ovarian tumourigenesis and advancements in the disease's (epi)genetic and molecular profiling, a paradigm shift has emerged with the identification of new disease biomarkers and the proposal of targeted therapeutic approaches to postpone disease recurrence and decrease side effects, while increasing patients' survival. Despite this progress, several challenges in disease management, including disease heterogeneity and drug resistance, still need to be overcome.

The Role of Cancer Stem Cell Markers in Ovarian Cancer

Ovarian cancer is the most lethal gynaecological cancer and the eighth most common female cancer. The early diagnosis of ovarian cancer remains a clinical problem despite the significant development of technology. Nearly 70% of patients with ovarian cancer are diagnosed with stages III-IV metastatic disease. Reliable diagnostic and prognostic biomarkers are currently lacking. Ovarian cancer recurrence and resistance to chemotherapy pose vital problems and translate into poor outcomes. Cancer stem cells appear to be responsible for tumour recurrence resulting from chemotherapeutic resistance. These cells are also crucial for tumour initiation due to the ability to self-renew, differentiate, avoid immune destruction, and promote inflammation and angiogenesis. Studies have confirmed an association between CSC occurrence and resistance to chemotherapy, subsequent metastases, and cancer relapses. Therefore, the elimination of CSCs appears important for overcoming drug resistance and improving prognoses. This review focuses on the expression of selected ovarian CSC markers, including CD133, CD44, CD24, CD117, and aldehyde dehydrogenase 1, which show potential prognostic significance. Some markers expressed on the surface of CSCs correlate with clinical features and can be used for the diagnosis and prognosis of ovarian cancer. However, due to the heterogeneity and plasticity of CSCs, the determination of specific CSC phenotypes is difficult.

Metabolomics profiling and chemoresistance mechanisms in ovarian cancer cell lines: Implications for targeting glutathione pathway

Ovarian cancer presents a significant challenge due to its high rate of chemoresistance, which complicates the effectiveness of drug-response therapy. This study provides a comprehensive metabolomic analysis of ovarian cancer cell lines OVCAR-3 and SK-OV-3, characterizing their distinct metabolic landscapes. Metabolomics coupled with chemometric analysis enabled us to discriminate between the metabolic profiles of these two cell lines. The OVCAR-3 cells, which are sensitive to doxorubicin (DOX), exhibited a preference for biosynthetic pathways associated with cell proliferation. Conversely, DOX-resistant SK-OV-3 cells favored fatty acid oxidation for energy maintenance. Notably, a marked difference in glutathione (GSH) metabolism was observed between these cell lines. Our investigations further revealed that GSH depletion led to a profound change in drug sensitivity, inducing a shift from a cytostatic to a cytotoxic response. The results derived from this comprehensive metabolomic analysis offer potential targets for novel therapeutic strategies to overcome drug resistance. Our study suggests that targeting the GSH pathway could potentially enhance chemotherapy's efficacy in treating ovarian cancer.

A platinum(II) complex HY1-Pt overcomes cisplatin-induced resistance and attenuates metastasis of epithelial ovarian cancer by cancer cell stemness inhibition

Tumor recurrence, acquired resistance and metastasis have severely limited the effect of clinical treatments for epithelial ovarian cancer. Recent researches reveal that cancer stem cells play important roles in the process of cisplatin-induced resistance and cancer cell metastasis. A platinum(II) complex (HY1-Pt) owning casein kinase 2 specificity reported in our recent research was herein applied to treat cisplatin-sensitive and cisplatin-resistant epithelial ovarian cancers, respectively, anticipating to achieve high anti-tumor efficacy. HY1-Pt showed highly efficient anti-tumor effect with low toxicity for either cisplatin-sensitive or cisplatin-resistant epithelial ovarian cancer both in vitro and in vivo. Biological studies indicated that HY1-Pt as a casein kinase 2 inhibitor could effectively overcome cisplatin resistance through the signaling pathway of Wnt/β-catenin by inhibiting expression of the signature genes of cancer stemness cells in A2780/CDDP cells. Moreover, HY1-Pt could suppress tumor migration and invasion in vitro and in vivo, further proving that HY1-Pt can be a potent novel platinum(II) agent for cisplatin-resistant epithelial ovarian cancer treatment.

Targeting ATP Synthase by Bedaquiline as a Therapeutic Strategy to Sensitize Ovarian Cancer to Cisplatin

Cisplatin is a common chemotherapeutic drug for treating ovarian cancer, but its clinical efficacy is hampered by intrinsic and acquired resistance. Previous studies had shown inhibiting oxidative phosphorylation overcomes cisplatin resistance in ovarian cancer. Studies reveal that bedaquiline, a clinically available antimicrobial drug, inhibits cancer via targeting mitochondria. This study systematically assessed the efficacy of bedaquiline in ovarian cancer and its underlying mechanism. Using a panel of ovarian cancer cell lines and normal ovary cells, we demonstrated bedaquiline is selective for anti-ovarian cancer activities. Furthermore, the sensitivity varied among different ovarian cancer cell lines regardless of their sensitivity to cisplatin. Bedaquiline inhibited growth, survival and migration, through decreasing levels of ATP synthase subunit, complex V activity, mitochondrial respiration and ATP. We further found that ovarian cancer displayed increased levels of ATP, oxygen consumption rate (OCR), complex V activity and ATP synthase subunits compared to normal counterpart. Combination index analysis showed that bedaquiline and cisplatin is synergistic. Bedaquiline remarkably enhanced the efficacy of cisplatin in inhibiting ovarian cancer growth in mice. Our study provides evidence to repurpose bedaquiline for ovarian cancer treatment and suggests that ATP synthase is a selective target to overcome cisplatin resistance in ovarian cancer.

Role of DNA De-methylation intermediate '5-hydroxymethylcytosine' in ovarian cancer management: A comprehensive review

Ovarian cancer remains the most eminent silent killer, with high morbidity and mortality among all gynaecological cancers. The advanced-stage patient's diagnosis has a low survival rate caused by its asymptomatic progression and diverse histopathological sub-types, wherefore in poor prognosis and highly recurring malignancy with multidrug resistance towards chemotherapy. Epigenetic biomarkers open promising avenues of intriguing research to combat OC malignancy, furthermore a tool for its early diagnosis. 5-hydroxymethycytosine (5-hmC), alias the sixth base of the genome, is an intermediate formed during the recently established DNA demethylation process and catalysed via ten-eleven translocation (TET) family of enzymes. It plays a significant role in regulating gene expression and has sparked interest in various cancer types. This review summarizes the role of active DNA demethylation process, its enzymes and intermediate 5-hmC in epigenetic landscape of ovarian cancer as a potent biomarker for clinical translation in identification of therapeutic targets, diagnostic and prognostic evaluation.

Human RNASET2: A Highly Pleiotropic and Evolutionary Conserved Tumor Suppressor Gene Involved in the Control of Ovarian Cancer Pathogenesis

Ovarian cancer represents one of the most malignant gynecological cancers worldwide, with an overall 5-year survival rate, being locked in the 25-30% range in the last decade. Cancer immunotherapy is currently one of the most intensively investigated and promising therapeutic strategy and as such, is expected to provide in the incoming years significant benefits for ovarian cancer treatment as well. Here, we provide a detailed survey on the highly pleiotropic oncosuppressive roles played by the human RNASET2 gene, whose protein product has been consistently reported to establish a functional crosstalk between ovarian cancer cells and key cellular effectors of the innate immune system (the monocyte/macrophages lineage), which is in turn able to promote the recruitment to the cancer tissue of M1-polarized, antitumoral macrophages. This feature, coupled with the ability of T2 ribonucleases to negatively affect several cancer-related parameters in a cell-autonomous manner on a wide range of ovarian cancer experimental models, makes human RNASET2 a very promising candidate to develop a "multitasking" therapeutic approach for innovative future applications for ovarian cancer treatment.

Polymeric nanoparticles-siRNA as an emerging nano-polyplexes against ovarian cancer

Ovarian cancer (OC) is considered fifth-deadliest cancer globally responsible for high mortality in women. As the conventional therapeutic and diagnostic approaches are ineffective in increasing the survival rates of advanced staged patients by more than 5 years, OC has resulted in high morbidity and mortality rates over the last two decades. As a result, there is a dire need for innovative treatment approaches to address the issues. RNAi and nanotechnology can be considered the most appropriate strategies that can be used to improve OC therapy and help circumvent the chemo-resistance. siRNA is considered highly successful in facilitating the knockdown of specific genes on entering the cytosol when administered in-vivo via inhibiting the mRNA expression responsible for translation of those specific genes through the mechanism called RNA interference (RNAi). However, the primary barrier of utmost importance in the clinical efficacy of employed siRNA for the treatment of OC is the systemic distribution to the targeted site from the administration site. As a result, nanoparticles are constructed to carry the siRNA molecules inside them to the targeted site by preventing serum degradation and enhancing the serum stability of administered siRNA. The present review assesses the developments made in the polymeric-based nanoparticle siRNA delivery for targeting particular genes involved in the prognosis of ovarian cancers and surpassing the chemo-resistance and thus improving the therapeutic potentials of administered agents.

Multiparameter Single-Cell Characterization of Ovarian Intratumor Heterogeneity

Cancer is a complex disease rooted in heterogeneity, which is the phenomenon of individual cells, tissues, or patients having distinct phenotypic and/or genetic characteristics. Observed divergent disease etiology is likely rooted, at least in part, in tumor heterogeneity and the classification of distinct and important subpopulations of cells within the tumor and its associated microenvironment has remained a technical challenge. Standard next-generation sequencing of bulk tumor tissue provides an overall average genetic profile of the sample, and masks contributions from individual cells and minor populations of cells, particularly in heterogeneous samples. Only with the advent of single-cell analysis and sequencing technologies has it become possible to characterize key contributions of cellular subpopulations in order to more comprehensively characterize disease. This chapter describes a method to generate linked phenotypic and genotypic data at single-cell resolution using a real-time single-cell resolved platform. Specifically, the example method provided here is used to link cellular growth kinetics and expression of a prognostic marker protein, CA-125, in cells derived from ovarian cancer patients with their single-cell genomic profiles, but the method is translatable to other cell types and phenotypes of interest.

Brilliant glycans and glycosylation: Seq and ye shall find

Proteoglycosylation is the addition of monosaccharides or glycans to the protein peptide chain. This is a common post-translational modification of proteins with a variety of biological functions. At present, more than half of all biopharmaceuticals in clinic are modified by glycosylation. Most glycoproteins are potential drug targets and biomarkers for disease diagnosis. Therefore, in-depth study of glycan structure of glycoproteins will ultimately improve the sensitivity and specificity of glycoproteins for clinical disease detection. With the deepening of research, the function and application value of glycans and glycosylation has gradually emerged. This review systematically introduces the latest research progress of glycans and glycosylation. It encompasses six cancers, four viruses, and their latest discoveries in Alzheimer's disease, allergic diseases, congenital diseases, gastrointestinal diseases, inflammation, and aging.

Differential gene expression identifies a transcriptional regulatory network involving ER-alpha and PITX1 in invasive epithelial ovarian cancer

Background

The heterogeneous subtypes and stages of epithelial ovarian cancer (EOC) differ in their biological features, invasiveness, and response to chemotherapy, but the transcriptional regulators causing their differences remain nebulous.

Methods

In this study, we compared high-grade serous ovarian cancers (HGSOCs) to low malignant potential or serous borderline tumors (SBTs). Our aim was to discover new regulatory factors causing distinct biological properties of HGSOCs and SBTs.

Results

In a discovery dataset, we identified 11 differentially expressed genes (DEGs) between SBTs and HGSOCs. Their expression correctly classified 95% of 267 validation samples. Two of the DEGs, TMEM30B and TSPAN1, were significantly associated with worse overall survival in patients with HGSOC. We also identified 17 DEGs that distinguished stage II vs. III HGSOC. In these two DEG promoter sets, we identified significant enrichment of predicted transcription factor binding sites, including those of RARA, FOXF1, BHLHE41, and PITX1. Using published ChIP-seq data acquired from multiple non-ovarian cell types, we showed additional regulatory factors, including AP2-gamma/TFAP2C, FOXA1, and BHLHE40, bound at the majority of DEG promoters. Several of the factors are known to cooperate with and predict the presence of nuclear hormone receptor estrogen receptor alpha (ER-alpha). We experimentally confirmed ER-alpha and PITX1 presence at the DEGs by performing ChIP-seq analysis using the ovarian cancer cell line PEO4. Finally, RNA-seq analysis identified recurrent gene fusion events in our EOC tumor set. Some of these fusions were significantly associated with survival in HGSOC patients; however, the fusion genes are not regulated by the transcription factors identified for the DEGs.

Conclusions

These data implicate an estrogen-responsive regulatory network in the differential gene expression between ovarian cancer subtypes and stages, which includes PITX1. Importantly, the transcription factors associated with our DEG promoters are known to form the MegaTrans complex in breast cancer. This is the first study to implicate the MegaTrans complex in contributing to the distinct biological trajectories of malignant and indolent ovarian cancer subtypes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08276-8.

The evolving role of MUC16 (CA125) in the transformation of ovarian cells and the progression of neoplasia

MUC16 (the cancer antigen CA125) is the most commonly used serum biomarker in epithelial ovarian cancer, with increasing levels reflecting disease progression. It is a transmembrane glycoprotein with multiple isoforms, undergoing significant changes through the metastatic process. Aberrant glycosylation and cleavage with overexpression of a small membrane-bound fragment consist MUC16-related mechanisms that enhance malignant potential. Even MUC16 knockdown can induce an aggressive phenotype but can also increase susceptibility to chemotherapy. Variable MUC16 functions help ovarian cancer cells avoid immune cytotoxicity, survive inside ascites and form metastases. This review provides a comprehensive insight into MUC16 transformations and interactions, with description of activated oncogenic signalling pathways, and adds new elements on the role of its differential glycosylation. By following the journey of the molecule from pre-malignant states to advanced stages of disease it demonstrates its behaviour, in relation to the phenotypic shifts and progression of ovarian cancer. Additionally, it presents proposed differences of MUC16 structure in normal/benign conditions and epithelial ovarian malignancy.

Atovaquone at clinically relevant concentration overcomes chemoresistance in ovarian cancer via inhibiting mitochondrial respiration

The poor outcomes in ovarian cancer necessitate new treatments. Strategies to interfere with oxidative phosphorylation have been recently highlighted for the treatment of ovarian tumors. Atovaquone, an approved antimicrobial drug, has demonstrated anti-cancer potential and ability in disrupting mitochondrial function. Here, we investigated the efficacy of atovaquone as single drug and its combination with cisplatin in ovarian cancer. We show that atovaquone at clinically achievable concentrations is active against ovarian cancer bulky and stem-cell like cells via inhibiting growth and colony formation, and inducing caspase-dependent apoptosis. In contrast, atovaquone either does not or inhibits normal cells in a less extent than in ovarian cancer cells. Mechanism studies using multiple independent approaches demonstrate that atovaquone acts on ovarian cancer cells via decreasing mitochondrial complex III which results in mitochondrial respiration inhibition, energy reduction and oxidative stress. In line with in vitro findings, atovaquone alone at non-toxic dose is effective in inhibiting ovarian cancer growth in vivo, and its combination with cisplatin is synergistic. Our study suggests that atovaquone is a promising candidate to the treatment of ovarian cancer. Our work also supports the notion that mitochondrial respiration is a therapeutic target in ovarian cancer.

The Exocrine Differentiation and Proliferation Factor (EXDPF) Gene Promotes Ovarian Cancer Tumorigenesis by Up-Regulating DNA Replication Pathway

The Exocrine Differentiation and Proliferation Factor (EXDPF) gene could promote exocrine while inhibit endocrine functions. Although it is well known that ovary is an endocrine organ, the functions of EXDPF in ovarian cancer development is still unknown. This study demonstrated that EXDPF gene is significantly higher expressed in ovarian tumors compared to normal ovarian tissue controls. EXDPF DNA amplification was exhibited in lots of human tumors including 7.19% of ovarian tumors. Also, high expression of EXDPF positively correlated with poor overall survival (OS) of ovarian cancer patients. EXDPF expression could be universally detected in most epithelial ovarian cancer cells (SKOV3, IGROV1, MACS, HO8910PM, ES2, COV362 and A2780) tested in this study. Knock-down of EXDPF by siRNA delivered by plasmid or lentivirus largely inhibited ovarian cancer cells, IGROV1 and SKOV3 proliferation, migration and tumorigenesis in vitro and/or in vivo. Knock-down of EXDPF sensitized SKOV3 cells to the treatment of the front-line drug, paclitaxel. Mechanism study showed that EXDPF enhanced DNA replication pathway to promote ovarian cancer tumorigenesis. In conclusion, this study demonstrated that EXDPF could be a potential therapeutic target as a pro-oncogene of ovarian cancer.

Glycomic-Based Biomarkers for Ovarian Cancer: Advances and Challenges

Ovarian cancer remains one of the most common causes of death among gynecological malignancies afflicting women worldwide. Among the gynecological cancers, cervical and endometrial cancers confer the greatest burden to the developing and the developed world, respectively; however, the overall survival rates for patients with ovarian cancer are worse than the two aforementioned. The majority of patients with ovarian cancer are diagnosed at an advanced stage when cancer has metastasized to different body sites and the cure rates, including the five-year survival, are significantly diminished. The delay in diagnosis is due to the absence of or unspecific symptoms at the initial stages of cancer as well as a lack of effective screening and diagnostic biomarkers that can detect cancer at the early stages. This, therefore, provides an imperative to prospect for new biomarkers that will provide early diagnostic strategies allowing timely mitigative interventions. Glycosylation is a protein post-translational modification that is modified in cancer patients. In the current review, we document the state-of-the-art of blood-based glycomic biomarkers for early diagnosis of ovarian cancer and the technologies currently used in this endeavor.

BRCA1 Expression by Immunohistochemistry and Prognosis in Ovarian Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Homologous recombination deficiencies are associated with increased platinum sensitivity and potential response to poly (ADP-ribose) polymerase inhibitors in epithelial ovarian cancer. As an alternative to germline testing or somatic tumor sequencing, BRCA1 deficiency can be detected by immunohistochemistry and might predict homologous recombination deficiencies.

OBJECTIVE

This study aimed to assess the association between BRCA1 expression by immunohistochemistry and the prognosis of patients with epithelial ovarian cancer.

METHODS

We conducted a systematic review and meta-analysis following the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement. We searched PubMed, EMBASE, Web of Science, and Scopus databases through July 2019. Reference lists of selected articles were screened for further studies. We conducted qualitative synthesis and meta-analyses of hazard ratios for overall survival and progression-free survival.

RESULTS

Of 41 studies of BRCA1 expression using immunohistochemistry, 18 evaluated the association of BRCA1 expression with patient survival (2738 cases). The loss of BRCA1 expression was associated with improved overall survival (hazard ratio = 0.67, 95% confidence interval 0.57-0.77) and progression-free survival (hazard ratio = 0.70, 95% confidence interval 0.58-0.84).

CONCLUSIONS

Negative BRCA1 expression assessed by immunohistochemistry was associated with a better prognosis in epithelial ovarian cancer.

Adenylate kinase 7 is a prognostic indicator of overall survival in ovarian cancer

Ovarian cancer (OC), a common malignant heterogeneous gynecological tumor, is the primary cause of cancer-related death in women worldwide. Adenylate kinase (AK) 7 belongs to the adenylate kinase (AK) family and is a cytosolic isoform of AK. Recent studies have demonstrated that AK7 is expressed in several human diseases, including cancer. However, there is a scarcity of reports on the relationship between AK7 and OC. Here, we compared the expression of AK7 in normal and cancerous ovarian tissues from The Cancer Genome Atlas database and used the c2 test to assess the correlation between AK7 levels and the clinical symptoms of OC. Finally, the prognostic significance of AK7 in OC was determined using the Kaplan-Meier analyses and Cox regression and performed gene set enrichment analysis to detect any relevant signaling pathways. We found that AK7 levels were substantially downregulated in OC than that in normal ovarian tissues (P < .001). Low AK7 levels were related to the patients' age (P = .0093) in OC. The median overall survival (OS) of patients with low AK7-expressing OC was shorter than patients with high AK7-expressing OC (P = .019). The Cox regression analysis (multivariate) identified low AK7 levels were independently related to the prognosis of OC (HR 1.34; P = .048). Our study demonstrated that the downregulated levels of AK7 could serve as an independent prognostic indicator for the OS in OC. Additionally, gene set enrichment analysis revealed that EMT, apical junction, TGF-b signaling, UV response, and myogenesis were associated in the low AK7 expression phenotype (NOM P < .05).

Regulation of invasion and peritoneal dissemination of ovarian cancer by mesothelin manipulation

Peritoneal dissemination is a particular form of metastasis typically observed in ovarian cancer and the major cause for poor patient’s outcome. Identification of the molecular players involved in ovarian cancer dissemination can offer an approach to develop treatment strategies to improve clinical prognosis. Here, we identified mesothelin (MSLN) as a crucial protein in the multistep process of peritoneal dissemination of ovarian cancer. We demonstrated that MSLN is overexpressed in primary and matched peritoneal metastasis of high-grade serous carcinomas (HGSC). Using several genetically engineered ovarian cancer cell lines, resulting in loss or gain of function, we found that MSLN increased cell survival in suspension and invasion of tumor cells through the mesothelial cell layer in vitro. Intraperitoneal xenografts established with MSLN^high ovarian cancer cell lines showed enhanced tumor burden and spread within the peritoneal cavity. These findings provide strong evidences that MSLN is a key player in ovarian cancer progression by triggering peritoneal dissemination and provide support for further clinical investigation of MSLN as a therapeutic target in HGSC.

Claudin 10 acts as a novel biomarker for the prognosis of patients with ovarian cancer

Ovarian cancer (OC) is one of the most fatal gynecological malignancies in the world and confers a poor 5-year survival rate. The present study was designed to discover novel prognostic markers for patients with OC in order to estimate disease metastasis or recurrence. Based on the large cohorts of transcriptome data from multicenter sources, a comprehensive analysis was performed to explore potential prognostic markers. A total of 269 differentially expressed genes were identified, of which 32 were upregulated and 237 downregulated in OC tissues compared with the corresponding expression in normal tissues. Kaplan-Meier analysis, log-rank test and nomogram analysis were employed to demonstrate that low expression levels of claudin 10 (CLDN10) were associated with a less favorable disease prognosis. The most promising prognostic marker for OC was subsequently selected. Additionally, the prognostic nomogram was constructed in order to assess the 5-year survival rate using CLDN10 expression as a prognostic marker for OC. Furthermore, gene set enrichment analysis and analysis of the tumor-associated competing endogenous RNA network were performed to elucidate the potential biological processes associated with CLDN10 expression. The current results indicated that CLDN10 may influence OC progression via transforming growth factor-β (TGF-β)- or WNT/β-catenin-induced epithelial-to-mesenchymal transition (EMT). The associations among CLDN10, microRNA-486-5p, TGF-β, WNT/β-catenin and EMT should be further investigated in future studies.

Overexpression of FNDC1 Relates to Poor Prognosis and Its Knockdown Impairs Cell Invasion and Migration in Gastric Cancer

The distribution and content of fibronectin is closely related to the occurrence and development of tumors. Fibronectin is widely involved in cell migration, adhesion, proliferation, hemostasis, and tissue repair. Fibronectin type III domain containing 1, as a primary component of the structural domain of fibronectin, is closely related to the occurrence of some cancers. However, the molecular mechanism of fibronectin type III domain containing 1 in gastric cancer has not been elaborated. In this study, we analyzed the expression and prognosis of fibronectin type III domain containing 1 by collecting data from Oncomine and GEPIA database. The expression of fibronectin type III domain containing 1 in gastric cancer cells was detected by quantitative real-time polymerase chain reaction in vitro. After knockdown of fibronectin type III domain containing 1 by small interfering RNA, the proliferation, invasion, and migration of AGS (human gastric adenocarcinoma cell line) cells and the function of epithelial–mesenchymal transition were measured by Cell Counting Kit-8, colony formation, transwell, and Western blot. The results showed that fibronectin type III domain containing 1 was highly expressed in gastric cancer tissues and its overexpression was significantly correlated with the prognosis of gastric cancer. In vitro, experiments revealed that knockdown of fibronectin type III domain containing 1 could inhibit the proliferation, migration, and invasion of gastric cancer cells, possibly by changing the epithelial–mesenchymal transition pathway. The findings elaborated the biological role of fibronectin type III domain containing 1 in gastric cancer and potential mechanism of action, possibly providing a new insight for future clinical diagnosis or even molecular therapy.

Understanding the Role of the Transcription Factor Sp1 in Ovarian Cancer: from Theory to Practice

Ovarian cancer (OC) is one of the deadliest cancers among women contributing to high risk of mortality, mainly owing to delayed detection. There is no specific biomarker for its detection in early stages. However, recent findings show that over-expression of specificity protein 1 (Sp1) is involved in many OC cases. The ubiquitous transcription of Sp1 apparently mediates the maintenance of normal and cancerous biological processes such as cell growth, differentiation, angiogenesis, apoptosis, cellular reprogramming and tumorigenesis. Sp1 exerts its effects on cellular genes containing putative GC-rich Sp1-binding site in their promoters. A better understanding of the mechanisms underlying Sp1 transcription factor (TF) regulation and functions in OC tumorigenesis could help identify novel prognostic markers, to target cancer stem cells (CSCs) by following cellular reprogramming and enable the development of novel therapies for future generations. In this review, we address the structure, function, and biology of Sp1 in normal and cancer cells, underpinning the involvement of Sp1 in OC tumorigenesis. In addition, we have highlighted the influence of Sp1 TF in cellular reprogramming of iPSCs and how it plays a role in controlling CSCs. This review highlights the drugs targeting Sp1 and their action on cancer cells. In conclusion, we predict that research in this direction will be highly beneficial for OC treatment, and chemotherapeutic drugs targeting Sp1 will emerge as a promising therapy for OC.

Disease-Specific Survival of Type I and Type II Epithelial Ovarian Cancers-Stage Challenges Categorical Assignments of Indolence & Aggressiveness

Epithelial ovarian cancers (EOC) consist of several sub-types based on histology, clinical, molecular and epidemiological features that are termed “histo-types”, which can be categorized into less aggressive Type I and more aggressive Type II malignancies. This investigation evaluated the disease-specific survival (DSS) of women with Type I and II EOC using histo-type, grade, and stage. A total of 47,789 EOC cases were identified in the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) data. Survival analysis and log rank test were performed to identify a 2-tiered classification (grade 1 vs. grade 2 & 3) for serous EOC. DSS of early stage serous EOC for grade 2 was significantly different from grade 3 indicating that a 2-tier classification for serous EOC applied only to late stage. DSS of Type I EOC was much better than Type II. However, DSS was 33–52% lower with late stage Type I than with early stage Type I indicating that Type I ovarian cancers should not be considered indolent. Early stage Type II EOC had much better DSS than late stage Type II stressing that stage has a large role in survival of both Type I and II EOC.

Ovarian cancer stem cells and targeted therapy

Background

Ovarian cancer has the highest ratio of mortality among gynecologic malignancies. Chemotherapy is one of the most common treatment options for ovarian cancer. However, tumor relapse in patients with advanced tumor stage is still a therapeutic challenge for its clinical management.

Main body

Therefore, it is required to clarify the molecular biology and mechanisms which are involved in chemo resistance to improve the survival rate of ovarian cancer patients. Cancer stem cells (CSCs) are a sub population of tumor cells which are related to drug resistance and tumor relapse.

Conclusion

In the present review, we summarized the recent findings about the role of CSCs in tumor relapse and drug resistance among ovarian cancer patients. Moreover, we focused on the targeted and combinational therapeutic methods against the ovarian CSCs.

Immunohistochemistry for the detection of BRCA1 and BRCA2 proteins in patients with ovarian cancer: a systematic review

BACKGROUND

Loss of function in either breast cancer type 1 susceptibility protein (BRCA1) or breast cancer type 2 susceptibility protein (BRCA2) is a major risk factor for epithelial ovarian cancer (EOC) development. BRCA1 or BRCA2 deficiencies are associated with short-term prognosis and might have importance for the treatment of women with the disease. However, the screening of all possible mechanisms of dysfunction is expensive, time-consuming and difficult to apply in clinical practice. On the other hand, immunohistochemistry (IHC) is a simple and reliable method to access the expression of several proteins in tumour tissues.

MATERIALS AND METHODS

This systematic review aims to evaluate the current usage of IHC to detect BRCA1 and BRCA2 deficiencies in EOC. We searched and evaluated all primary literature on the use of IHC for evaluating BRCA1 and BRCA2 proteins expression in EOC. The main concepts for the search were: ovarian neoplasms, IHC, BRCA1 and BRCA2.

RESULTS

Forty-four studies from 925 unique titles were included. A total of 4206 tumour samples were evaluated for BRCA1 and 1041 for BRCA2 expression. Twelve BRCA1 primary antibodies were used in 41 studies, and the most common was the MS110 clone (75.6%). Seven BRCA2 primary antibodies were used in ten studies. Using the cut-off of 10%, 47.0% of EOCs are associated with loss of BRCA1 and 34.5% with the loss of BRCA2 expression.

CONCLUSION

IHC was effective to detect loss of BRCA1 protein expression in EOC; however, data on BRCA2 expression were heterogeneous and difficult to interpret.

Circulating non-coding RNAs in recurrent and metastatic ovarian cancer

Ovarian cancer has a poor outcome because it is usually detected at advanced tumor stages, and the majority of the patients develop disease relapse as a result of chemotherapy resistance. This most lethal gynecological malignancy metastasizes within the peritoneal fluid or ascites to pelvic and distal organs. In ovarian cancer progression and metastasis, small non-coding RNAs (ncRNAs), including long noncoding RNAs and microRNAs have been recognized as important regulators. Their dysregulation modulates gene expression and cellular signal pathways and can be detected in liquid biopsies. In this review, we provide an overview on circulating plasma and serum ncRNAs participating in tumor cell migration and invasion, and contributing to recurrence and metastasis of ovarian cancer. We will also discuss the development of potential, novel therapies using ncRNAs as target molecules or tumor markers for ovarian cancer.

Chronic iron exposure and c-Myc/H-ras-mediated transformation in fallopian tube cells alter the expression of EVI1, amplified at 3q26.2 in ovarian cancer

Mechanisms underlying the pathogenesis of high-grade serous epithelial ovarian cancers (HGSOC) are not yet well defined although key precursor cells have been identified (including fimbriated fallopian tube epithelium, FTSECs). Since iron is elevated in endometriotic cysts and the pelvic cavity, it is suggested that this source of redox-active iron may contribute to ovarian cancer pathogenesis. Specifically, sources of nontransferrin-bound iron (NTBI) within the pelvic cavity could arise from ovulation, retrograde menstruation, follicular fluid, or iron overload conditions (i.e., hemochromatosis). Herein, we investigated the cellular response of p53-inactivated and telomerase-expressing (immortalized) FTSECs (Pax8⁺/FoxJ1⁻) to NTBI (presented as ferric ammonium citrate (FAC), supplemented in media for >2 months) in order to assess its ability to promote the transition to a tumor-like phenotype; this cellular response was compared with immortalized FTSECs transformed with H-Ras^V12A and c-Myc^T58A. Both approaches resulted in increased cell numbers and expression of the oncogenic transcriptional regulator, ecotropic virus integration site 1 (EVI1, a gene most frequently amplified at 3q26.2 in HGSOC, represented by multiple variants), along with other oncogenic gene products. In contrast to the transformed cells, FAC-exposed FTSECs elicited elevated migratory capacity (and epithelial–mesenchymal transition mRNA profile) along with increased expression of DNA damage response proteins (i.e., FANCD2) and hTERT mRNA relative to controls. Interestingly, in FAC-exposed FTSECs, EVI1 siRNA attenuated hTERT mRNA expression, whereas siRNAs targeting β-catenin and BMI1 (both elevated with chronic iron exposure) reduced Myc and Cyclin D1 proteins. Collectively, our novel findings provide strong foundational evidence for potential iron-induced initiation events, including EVI1 alterations, in the pathogenesis of HGSOC, warranting further in depth investigations. Thus, these findings will substantially advance our understanding of the contribution of iron enriched within the pelvic cavity, which may identify patients at risk of developing this deadly disease.

Ovarian Cancer Treatment Stratification Using Ex Vivo Drug Sensitivity Testing

BACKGROUND

Treatment options for patients with platinum-resistant ovarian cancer are generally palliative in nature and rarely have realistic potential to be curative. Because many patients with recurrent ovarian cancer receive aggressive chemotherapy for prolonged periods, sometimes continuously, therapy-related toxicities are a major factor in treatment decisions. The use of ex vivo drug sensitivity screens has the potential to improve the treatment of patients with platinum-resistant ovarian cancer by providing personalized treatment plans and thus reducing toxicity from unproductive therapy attempts.

MATERIALS AND METHODS

We evaluated the treatment responses of a set of six early-passage patient-derived ovarian cancer cell lines towards a set of 30 Food and Drug Administration-approved chemotherapy drugs using drug-sensitivity testing.

RESULTS

We observed a wide range of treatment responses of the cell lines. While most compounds displayed vastly different treatment responses between cell lines, we found that some compounds such as docetaxel and cephalomannine reduced cell survival of all cell lines.

CONCLUSION

We propose that ex vivo drug-sensitivity screening holds the potential to greatly improve patient outcomes, especially in a population where multiple continuous treatments are not an option due to advanced disease, rapid disease progression, age or poor overall health. This approach may also be useful to identify potential novel therapeutics for patients with ovarian cancer.

Changes in the Management and Prognosis of Ovarian Cancer Due to the New FIGO and WHO Classifications: A Case Series Observational Descriptive Study. Seven Years of Follow-up

OBJECTIVE

Ovarian cancer is the deadliest of gynecologic cancers. In recent years, International Federation of Gynecology and Obstetrics (FIGO) and the World Health Organization (WHO) classifications were revised. We compared the major changes between the classifications and examined the effects on the therapy and prognosis of the ovarian, fallopian tubes, and peritoneum cancer in our series according to both classifications.

METHODS/MATERIALS

We performed an observational descriptive study of 210 patients who were diagnosed with a malignant ovarian tumor from 2010 to 2016. The accepted FIGO and WHO classifications at each point in time were registered. We reclassified both data, obtaining both classifications for each patient. The changes in the therapeutic management and prognosis were examined.

RESULTS

In both FIGO classifications of our case series, most patients with ovarian cancer were in FIGO stage III. We found that 4.2% of the previous stage IIIC patients have changed to stage IIIA2 or stage IIIB, with better prognosis and survival rate. In the new WHO classification, the main change, in our case series, was the increase in the high-grade serous carcinoma percentage. According to the current recommendations, we observed 7.56% more patients in early ovarian cancer stages treated with platinum and taxane. In both early and advanced ovarian cancer group, high-grade serous carcinoma tumors were predominant.

CONCLUSIONS

The newly created WHO and FIGO classifications have improved the ability to predict the prognosis and consequently to change the therapeutic managements of patients with ovarian cancer.

Circulating Mitochondrial DNA is Linked to Progression and Prognosis of Epithelial Ovarian Cancer

As peripheral blood contains fluctuated levels of circulating cell-free mitochondrial DNA (ccf mtDNA), we aimed to evaluate ccf mtDNA as a biomarker for diagnosis and prognosis of epithelial ovarian cancer (EOC). In the present study, we recruited 165 EOC patients and 60 healthy women. Quantitative RT-PCR was applied to amplify 79-bp and 230-bp fragments of the mitochondrial 16 s RNA gene in sera of these participants. MtDNA integrity was defined as the ratio of long to short mtDNA fragments. We observed that the levels of mtDNA79 and mtDNA230 were significantly increased (P = .0001), whereas the mtDNA integrity (P = .0001) was decreased in EOC patients compared with those in healthy controls. MtDNA79 showed a sensitivity of 90.3% and a specificity of 81.7% (AUC = 0.900) to discriminate EOC from healthy controls. Moreover, the amounts of mtDNA79 (P = .0001, P = .012, P = .039) and mtDNA230 (P = .0001, P = .042) continuously raised from healthy controls over FIGO I-II to FIGO III and IV, with highest levels of mtDNA79 (P = .0001) and mtDNA230 (P = .0001) in FIGO III and IV. Increasing levels of mtDNA79 (P = .003, P = .0001) and mtDNA230 (P = .041, P = .0001) were also associated with lymph node metastasis and CA125 values. The higher levels of mtDNA79 (P = .0001; HR 3.2, 95%CI:1.6-6.3) and mtDNA230 (borderline P = .048, HR 0.9, 95%CI:0.9-1.0) also correlated with poor patients' overall survival, of which mtDNA79 could act as an independent factor for overall survival. Our data show a significant association of increasing levels of ccf mtDNA with EOC progress and poor prognosis.

Detecting ovarian cancer using extracellular vesicles: progress and possibilities

Ovarian cancer (OC) is the deadliest gynecological malignancy. Most patients are diagnosed when they are already in the later stages of the disease. Earlier detection of OC dramatically improves the overall survival, but this is rarely achieved as there is a lack of clinically implemented biomarkers of early disease. Extracellular vesicles (EVs) are small cell-derived vesicles that have been extensively studied in recent years. They contribute to various aspects of cancer pathology, including tumor growth, angiogenesis and metastasis. EVs are released from all cell types and the macromolecular cargo they carry reflects the content of the cells from which they were derived. Cancer cells release EVs with altered cargo into biofluids, and so, they represent an excellent potential source of novel biomarkers for the disease. In this review, we describe the latest developments in EVs as potential biomarkers for earlier detection of OC. The field is still relatively young, but many studies have shown that EVs and the cargo they carry, including miRNAs and proteins, can be used to detect OC. They could also give insights into the stage of the disease and predict the likely therapeutic outcome. There remain many challenges to the use of EVs as biomarkers, but, through ongoing research and innovation in this exciting field, there is great potential for the development of diagnostic assays in the clinic that could improve patient outcome.

siRNA-Conjugated Nanoparticles to Treat Ovarian Cancer

Ovarian cancer is the fifth-most lethal cancer among women due to a lack of early detection and late-stage treatment options, and it is responsible for more than 14,000 deaths each year in the United States. Recently, there have been advances in RNA interference therapy, specifically with small interfering RNA (siRNA), to reduce tumor burden for ovarian cancer via gene down-regulation. However, delivery of siRNA poses its own challenges, as siRNA is unstable in circulation, is unable to be effectively internalized by cells, and may cause toxicity in off-target sites. To address such challenges, nanoparticle carriers have emerged as delivery platforms for the biocompatible, targeted delivery of siRNA-based therapies. Several preclinical studies have shown the promising effects of siRNA therapy to reduce chemotherapy resistance and proliferation of ovarian cancer cells. This review evaluates the recent advances, clinical applications, and future potential of nanoparticle-mediated delivery of siRNA therapeutics to target genes implicated in ovarian cancer.

Inhibition of mitochondrial translation as a therapeutic strategy for human ovarian cancer to overcome chemoresistance

Aberrant increase in mitochondrial biogenesis is common in human ovarian cancer and has great therapeutic value. In this work, we demonstrate that tigecycline, a FDA-approved broad spectrum antibiotic, selectively targets ovarian cancer cells through inhibition of mitochondrial translation. Tigecycline dose-dependently inhibits proliferation of ovarian cancer cells via arresting them at G2/M phase and induces apoptosis through caspase pathway. At the same concentration, tigecycline either does not or inhibits normal cells in a less extent than ovarian cancer cells. Mechanistically, tigecycline specifically inhibits translation by mitochondrial ribosome but not nuclear or cytosolic ribosome, leading to mitochondrial dysfunction, oxidative stress and damage, AMPK activation and inhibition of mTOR signaling in ovarian cancer cells. We further show that the inhibitory effects on ovarian cancer cell by tigecycline is mediated by its suppression of mitochondrial respiration. Importantly, the combination of tigecycline and cisplatin at sublethal concentration results in much greater efficacy than cisplatin alone in vitro and in vivo. Additionally, the effective dose of tigecycline in ovarian cancer is clinically achievable. Our study suggests that tigecycline is a useful addition to the treatment of ovarian cancer. Our work also highlights the targeted therapeutic potential of mitochondrial respiration in ovarian cancer.

When Is "Type I" Ovarian Cancer Not "Type I"? Indications of an Out-Dated Dichotomy

The dualistic classification of epithelial ovarian cancer (EOC) into “type I” and “type II” is widely applied in the research setting; it is used as a convenient way of conceptualizing different mechanisms of tumorigenesis. However, this classification conflicts with recent molecular insights of the etiology of EOC. Molecular and cell of origin studies indicate that while type II tumors could be classed together, type I tumors are not homogenous, even within the histological types, and can have poor clinical outcomes. Type II high grade serous carcinoma and type I low grade serous carcinomas best fit the description of the dualistic model, with different precursors, and distinct molecular profiles. However, endometriosis-associated cancers should be considered a separate group, without assuming an indolent course or type I genetic profiles. Furthermore, the very clear differences between mucinous ovarian carcinomas and other type I tumors, including an uncertain origin, and heterogeneous mutational spectrum and clinical behavior, indicate a non-type I classification for this entity. The impression that only type II carcinomas are aggressive, have poor prognosis, and carry TP53 mutations is an unhelpful misinterpretation of the dualistic classification. In this review, we revisit the history of EOC classification, and discuss the misunderstanding of the dualistic model by comparing the clinical and molecular heterogeneity of EOC types. We also emphasize that all EOC research, both basic and clinical, should consider the subtypes as different diseases beyond the type I/type II model, and base novel therapies on the molecular characteristics of each tumor.

Potential clinical applications of circulating cell-free DNA in ovarian cancer patients

Circulating cell-free DNA (cfDNA) consists of small fragments of DNA that circulate freely in the bloodstream. In cancer patients, a fraction of cfDNA is derived from tumour cells, therefore containing the same genetic and epigenetic alterations, and is termed circulating cell-free tumour DNA. The potential use of cfDNA, the so-called 'liquid biopsy', as a non-invasive cancer biomarker has recently received a lot of attention. The present review will focus on studies concerning the potential clinical applications of cfDNA in ovarian cancer patients.

The potential role of miRNAs and exosomes in chemotherapy in ovarian cancer

Chemoresistance is one of the major obstacles in the treatment of cancer patients. It poses a fundamental challenge to the effectiveness of chemotherapy and is often linked to relapse in patients. Chemoresistant cells can be identified in different types of cancers; however, ovarian cancer has one of the highest rates of chemoresistance-related relapse (50% of patients within 5 years). Resistance in cells can either develop through prolonged cycles of treatment or through intrinsic pathways. Mechanistically, the problem of drug resistance is complex mainly because numerous factors are involved, such as overexpression of drug efflux pumps, drug inactivation, DNA repair mechanisms and alterations to and/or mutations in the drug target. Additionally, there is strong evidence that circulating miRNAs participate in the development of chemoresistance. Recently, miRNAs have been identified in exosomes, where they are encapsulated and hence protected from degradation. These miRNAs within exosomes (exo-miRNAs) can regulate the gene expression of target cells both locally and systemically. Exo-miRNAs play an important role in disease progression and can potentially facilitate chemoresistance in cancer cells. In addition, and from a diagnostic perspective, exo-miRNAs profiles may contribute to the development of predictive models to identify responder and non-responder chemotherapy. Such model may also be used for monitoring treatment response and disease progression. Exo-miRNAs may ultimately serve as both a predictive biomarker for cancer response to therapy and as a prognostic marker for the development of chemotherapy resistance. Therefore, this review examines the potential role of exo-miRNAs in chemotherapy in ovarian cancer.

Tumor evolution and chemoresistance in ovarian cancer

Development of novel strategies to overcome chemoresistance is central goal in ovarian cancer research. Natural history of the cancer development and progression is being reconstructed by genomic datasets to understand the evolutionary pattern and direction. Recent studies suggest that intra-tumor heterogeneity (ITH) is the main cause of treatment failure by chemoresistance in many types of cancers including ovarian cancer. ITH increases the fitness of tumor to adapt to incompatible microenvironment. Understanding ITH in relation to the evolutionary pattern may result in the development of the innovative approach based on individual variability in the genetic, environment, and life style. Thus, we can reach the new big stage conquering the cancer. In this review, we will discuss the recent advances in understanding ovarian cancer biology through the use of next generation sequencing (NGS) and highlight areas of recent progress to improve precision medicine in ovarian cancer.

Icaritin induces ovarian cancer cell apoptosis through activation of p53 and inhibition of Akt/mTOR pathway

AIMS

Ovarian cancer (OC) has the highest mortality rate of all gynecological cancers. Currently, the first-line OC treatment consists of cytoreductive surgery and platinum-based chemotherapy. However, most patients develop chemoresistance after the first-line treatment limits the success of treatment. Therefore, there is an urgent need to identify effective therapeutic agents.

MAIN METHODS

Cell viabilities were detected by MTS assay; Annexin V-FITC/PI assay and western blotting assay were performed to analyze the apoptotic cells in vitro; An immunofluorescence assay was performed to analyze the TUNEL⁺ apoptotic cells in vivo; Patient-derived xenografts were established to test the in vivo antitumor effects; The key proteins of p53, caspase-mediated apoptotic pathway and Akt/mTOR pathway were detected by Western blotting.

KEY FINDINGS

Icaritin, a prenylflavonoid derivative from Epimedium Genus, inhibited the proliferation of drug-sensitive OC cells (OV2008 and C13*) and cisplatin resistant OC cells A2780cp. Icaritin induced OC cell apoptosis in vitro, as indicated by the increase of Annexin V⁺/PI⁺ apoptotic cells analyzed with flow cytometry, and the cleavage of caspase 9, caspase 3 and poly-ADP-ribose polymerase (PARP) detected with western blotting. Icaritin also inhibited tumor growth and induced OC cells apoptosis in patient-derived xenografts, as indicated by the tumor growth delay and increase of TUNEL-positive cells in tumor tissues. The icaritin-induced OC cell apoptosis may be associated with the activation of p53 and the suppression of Akt/mTOR pathway.

SIGNIFICANCE

This study sheds light on the underlying mechanisms of antitumor effect of icaritin, and warrants clinical trial for treatment of OC.

Improving cancer detection through combinations of cancer and immune biomarkers: a modelling approach

Background

Early cancer diagnosis is one of the most important challenges of cancer research, since in many cancers it can lead to cure for patients with early stage diseases. For epithelial ovarian cancer (which is the leading cause of death among gynaecologic malignancies) the classical detection approach is based on measurements of CA-125 biomarker. However, the poor sensitivity and specificity of this biomarker impacts the detection of early-stage cancers.

Methods

Here we use a computational approach to investigate the effect of combining multiple biomarkers for ovarian cancer (e.g., CA-125 and IL-7), to improve early cancer detection.

Results

We show that this combined biomarkers approach could lead indeed to earlier cancer detection. However, the immune response (which influences the level of secreted IL-7 biomarker) plays an important role in improving and/or delaying cancer detection. Moreover, the detection level of IL-7 immune biomarker could be in a range that would not allow to distinguish between a healthy state and a cancerous state. In this case, the construction of solution diagrams in the space generated by the IL-7 and CA-125 biomarkers could allow us predict the long-term evolution of cancer biomarkers, thus allowing us to make predictions on cancer detection times.

Conclusions

Combining cancer and immune biomarkers could improve cancer detection times, and any predictions that could be made (at least through the use of CA-125/IL-7 biomarkers) are patient specific.

Diagnostic Model of Serum miR-193a-5p, HE4 and CA125 Improves the Diagnostic Efficacy of Epithelium Ovarian Cancer

Epithelium ovarian cancer (EOC) is currently the prevalent malignant cancer worldwide. However, there is a lack of efficient biomarkers for EOC screening. Accumulating evidence reveals that serum miRNA detectable in various types of cancer. Therefore, we explore the diagnostic value of combined detection of plasma miR-193a-5p, HE4 and CA125 for EOC. Serum samples were collected from 45 patients with primary EOC, 30 patients with benign ovarian tumor patients and 40 healthy controls. The expression of serum miR-193a-5p was detected by real-time quantitative PCR, and serum HE4 and CA125 were detected by chemiluminescent immunoassay. Moreover, a diagnostic model combining miR-193a-5p, HE4 and CA125 or alone in EOC patients was evaluated by ROC curve analysis. The relative expression quantity (RQ) of serum miR-193a-5p in EOC patients, benign ovarian tumor patients and healthy control groups were 0.419 (0.093, 2.215), 3.667 (1.633, 6.691) and 1.130 (1.000, 7.087), respectively. The RQ of serum miR-193a-5p in EOC patients was significantly lower than that in benign ovarian tumor patients and healthy controls (both P < 0.001), and there was no significant difference between benign ovarian tumor patients and healthy controls (both P > 0.05). There was no significant correlation between serum miR-193-5p, HE4 and CA125 levels (both P > 0.05). Additionally a risk model for miR-193a-5p, HE4 and CA125 was correlated with Grading and Lymph node metastasis (P = 0.016, P = 0.029). The area under the receiver operating characteristic curve of a risk model for distinguishing EOC patients from healthy individuals was 0.996, which higher than any single biomarker. Combined detection of miR-193-5p, HE4 and CA125 by logistic regression analysis could greatly improved the diagnostic ability of EOC and may prove to be a candidate biomarker, providing new directions for further investigation.

PIM Kinases and Their Relevance to the PI3K/AKT/mTOR Pathway in the Regulation of Ovarian Cancer

Ovarian cancer is a medical term that includes a number of tumors with different molecular biology, phenotypes, tumor progression, etiology, and even different diagnosis. Some specific treatments are required to address this heterogeneity of ovarian cancer, thus molecular characterization may provide an important tool for this purpose. On a molecular level, proviral-integration site for Moloney-murine leukemia virus (PIM) kinases are over expressed in ovarian cancer and play a vital role in the regulation of different proteins responsible for this tumorigenesis. Likewise, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is also a central regulator of the ovarian cancer. Interestingly, recent research has linked the PIM kinases to the PI3K/AKT/mTOR pathway in several types of cancers, but their connection in ovarian cancer has not been studied yet. Once the exact relationship of PIM kinases with the PI3K/AKT/mTOR pathway is acquired in ovarian cancer, it will hopefully provide effective treatments on a molecular level. This review mainly focuses on the role of PIM kinases in ovarian cancer and their interactions with proteins involved in its progression. In addition, this review suggests a connection between the PIM kinases and the PI3K/AKT/mTOR pathway and their parallel mechanism in the regulation of ovarian cancer.

The association between p53 protein phosphorylation at serine 15, serine 20 and sensitivity of cells isolated from patients with ovarian cancer and cell lines to chemotherapy in in vitro study

BACKGROUND

The association between p53 protein phosphorylated at serine 15 (Ser15), serine 20 (Ser20) and ovarian tumor cell sensitivity after chemotherapy was analyzed in order to define the influence of p53 activation on tumor cell sensitivity to chemotherapy.

METHODS

The study was performed on ovarian cancer cell line (OvBH-1), colon adenocarcinoma metastasis to ovary (SW626) and on cells isolated from ascitic fluids from patients with ovarian cancer: with (p53+) or without (p53-) p53 nuclear protein accumulation. p53 protein, Ser15, Ser20, Bax, Noxa and PgP protein expression was evaluated by means of immunocytochemical staining before and after chemotherapy. Cell viability after treatment was estimated using MTT assay.

RESULTS

Cell lines and tumor cells p53+, p53- revealed a significant decrease in cell survival after camptothecin, paclitaxel, cisplatin treatment, compared to the control group (p < 0.01). In p53+ group, the expression of Ser20 significantly increased after camptothecin and paclitaxel (p < 0.05). Ser15, Ser20, Bax, Noxa expression correlated with MTT and depended on p53+, p53- tumor cell and the drug used (p < 0.05). Expression of Bax and Noxa were dependent on the type of tumor cells and drug used. The correlation between Ser15, Ser20 and Bax, Noxa expression was found in cell lines and tumor cells (p < 0.05).

CONCLUSIONS

Our study suggests that the relation between Ser15 or Ser20 and tumor cell viability might reflect their role in tumor sensitivity on chemotherapy in dependent p53 protein status. Revealed association between p53 protein phosphorylated at Ser15, Ser20 and Bax, Noxa protein expression determined the apoptotic activity of tumor cells.

The small vesicular culprits: the investigation of extracellular vesicles as new targets for cancer treatment

Extracellular vesicles (EVs) are membranous vesicles released from almost all type of cells including cancer cells. EVs transfer their components, such as microRNAs (miRNAs), messenger RNAs, lipids and proteins, from one cell to another, affecting the target cells. Emerging evidence suggests that reciprocal interactions between cancer cells and the cells in their microenvironment via EVs drive disease progression and therapy resistance. Therefore, understanding the roles of EVs in cancer biology will provide us with new opportunities to treat patients. EVs are also useful for monitoring disease processes. EVs have been found in many kinds of biological fluids such as blood, urine, saliva and semen. Because of their accessibility, EVs offer ease of collection with minimal discomfort to patients and are preferred for serial collection. In addition, they reflect and carry dynamic changes in disease, allowing us to access crucial molecular information about the disease status. Therefore, EVs hold great possibility as clinically useful biomarkers to provide multiple non-invasive snapshots of primary and metastatic tumors. In this review, we summarize current knowledge of miRNAs in EVs in cancer biology and as biomarkers. Furthermore, we discuss the potential of miRNAs in EVs for clinical application.

Diagnostic and prognostic relevance of circulating exosomal miR-373, miR-200a, miR-200b and miR-200c in patients with epithelial ovarian cancer

Exosomes are membrane vesicles that mediate intercellular communication by transporting their molecular cargo from cell to cell. We investigated whether serum levels of exosomal miR-373, miR-200a, miR-200b and miR-200c and circulating exosomes have diagnostic and prognostic relevance in a cohort of 163 epithelial ovarian cancer (EOC) patients using TaqMan MicroRNA assays and ELISA. The serum concentrations of exosomal miR-373 (p = 0.0001), miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.028) were significantly higher in EOC patients than healthy women. The levels of miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.019) could distinguish between malignant and benign ovarian tumors. While the levels of miR-373 and miR-200a were increased in all FIGO/lymph node stages (p = 0.0001), the levels of miR-200b and miR-200c were higher in patients with FIGO stage III–IV (p = 0.0001, p = 0.008, respectively) including lymph node metastasis (p = 0.0001, p = 0.004, respectively) than FIGO stages I–II. The increased levels of miR-200b and miR-200c were also associated with CA125 values (p = 0.0001, p = 0.0001, respectively) and a shorter overall survival (p = 0.007, p = 0.017, respectively). The levels of exosomes were excessively elevated in EOC patients (p = 0.0001). In all three cohorts, they were positively associated with the serum levels of exosomal miR-373 (p = 0.004), miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.008). In conclusion, the increased levels of exosomal miR-200b and miR-200c mainly observed in advanced EOC suggest that these microRNAs may be involved in tumor progression. The high concentrations of exosomes in EOC patients imply an excessive, active exosomal secretion in EOC.

The Diagnostic and Prognostic Potential of microRNAs in Epithelial Ovarian Carcinoma

Ovarian cancer causes more than 100,000 deaths globally per year. Despite intensive research efforts, there has been little improvement in the overall survival of patients over the past three decades. Most patients are not diagnosed until the cancer is at an advanced stage, by which time their chances of still being alive after 5 years are appallingly low. Attempts to extend life in these patients have been, for the most part, unsuccessful. This owes partly to the lack of suitable biomarkers for stratifying patients at the molecular level, into responders and non-responders. This would lead to more drugs being shown to have a clinical benefit and being approved for use in subgroups of patients. There is also a desperate need for improved biomarkers for earlier detection of ovarian cancer; if the disease is detected sooner there is a significantly improved outlook. In this review, we outline the evidence that microRNAs are deregulated in ovarian cancer, what this can tell us about tumour progression and how it could be used to improve patient stratification in clinical trials. We also describe the potential for circulating microRNAs, both associated with proteins or carried in vesicles, to be used as diagnostics for earlier detection or as biomarkers for informing clinicians on the prognosis and best treatment of ovarian cancer.

A combination of circulating miRNAs for the early detection of ovarian cancer

Ovarian cancer is the leading cause of gynecologic cancer mortality, due to the difficulty of early detection. Current screening methods lack sufficient accuracy, and it is still challenging to propose a new early detection method that improves patient outcomes with less-invasiveness. Although many studies have suggested the utility of circulating microRNAs in cancer detection, their potential for early detection remains elusive. Here, we develop novel predictive models using a combination of 8 circulating serum miRNAs. This method was able to successfully distinguish ovarian cancer patients from healthy controls (area under the curve, 0.97; sensitivity, 0.92; and specificity, 0.91) and early-stage ovarian cancer from patients with benign tumors (0.91, 0.86 and 0.83, respectively). This method also enables subtype classification in 4 types of epithelial ovarian cancer. Furthermore, it is found that most of the 8 miRNAs were packaged in extracellular vesicles, including exosomes, derived from ovarian cancer cells, and they were circulating in murine blood stream. The circulating miRNAs described in this study may serve as biomarkers for ovarian cancer patients. Early detection and subtype determination prior to surgery are crucial for clinicians to design an effective treatment strategy for each patient, as is the goal of precision medicine.

Androgen receptor gene CAG repeat polymorphism and ovarian cancer risk: A meta-analysis

Ovarian cancer is one of the common gynecological malignancies worldwide. It is usually diagnosed at a later stage, thus missing the best opportunity for treatment. Despite the advancement of ovarian cancer treatment, the prognosis is still poor. Androgen receptor (AR) may play a role in ovarian carcinogenesis. Previous studies regarding the association between AR CAG repeat length and ovarian cancer risk reported inconsistent results. Therefore, we conducted a meta-analysis to evaluate the association between AR CAG repeat length and ovarian cancer risk following the MOOSE guidelines. PubMed, Web of Science, EBSCO and other databases were searched up to September 15^th 2016. Case control studies with clear definition of CAG repeat length and detailed genotype information were included. Two authors independently reviewed and extracted data. Pooled analysis and subgroup analysis stratified by ethnicity were performed for different genetic models. Begg's funnel plot and Egger's test were performed for publication bias estimation. Overall, there was no association between the AR CAG repeat polymorphism and ovarian cancer risk. However, short CAG repeat polymorphism was associated with increased ovarian cancer risk in African Americans and Chinese under the dominant model, whereas a reverse association was observed in Caucasians and Italians under the other three models. Our study results should be interpreted with caution. Further well-designed epidemiological and functional studies are needed to elucidate the role of AR in ovarian carcinogenesis.

Diagnostic and prognostic relevance of circulating exosomal miR-373, miR-200a, miR-200b and miR-200c in patients with epithelial ovarian cancer

Exosomes are membrane vesicles that mediate intercellular communication by transporting their molecular cargo from cell to cell. We investigated whether serum levels of exosomal miR-373, miR-200a, miR-200b and miR-200c and circulating exosomes have diagnostic and prognostic relevance in a cohort of 163 epithelial ovarian cancer (EOC) patients using TaqMan MicroRNA assays and ELISA. The serum concentrations of exosomal miR-373 (p = 0.0001), miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.028) were significantly higher in EOC patients than healthy women. The levels of miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.019) could distinguish between malignant and benign ovarian tumors. While the levels of miR-373 and miR-200a were increased in all FIGO/lymph node stages (p = 0.0001), the levels of miR-200b and miR-200c were higher in patients with FIGO stage III-IV (p = 0.0001, p = 0.008, respectively) including lymph node metastasis (p = 0.0001, p = 0.004, respectively) than FIGO stages I-II. The increased levels of miR-200b and miR-200c were also associated with CA125 values (p = 0.0001, p = 0.0001, respectively) and a shorter overall survival (p = 0.007, p = 0.017, respectively). The levels of exosomes were excessively elevated in EOC patients (p = 0.0001). In all three cohorts, they were positively associated with the serum levels of exosomal miR-373 (p = 0.004), miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.008). In conclusion, the increased levels of exosomal miR-200b and miR-200c mainly observed in advanced EOC suggest that these microRNAs may be involved in tumor progression. The high concentrations of exosomes in EOC patients imply an excessive, active exosomal secretion in EOC.

Diagnostic and prognostic relevance of circulating exosomal miR-373, miR-200a, miR-200b and miR-200c in patients with epithelial ovarian cancer

Exosomes are membrane vesicles that mediate intercellular communication by transporting their molecular cargo from cell to cell. We investigated whether serum levels of exosomal miR-373, miR-200a, miR-200b and miR-200c and circulating exosomes have diagnostic and prognostic relevance in a cohort of 163 epithelial ovarian cancer (EOC) patients using TaqMan MicroRNA assays and ELISA. The serum concentrations of exosomal miR-373 (p = 0.0001), miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.028) were significantly higher in EOC patients than healthy women. The levels of miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.019) could distinguish between malignant and benign ovarian tumors. While the levels of miR-373 and miR-200a were increased in all FIGO/lymph node stages (p = 0.0001), the levels of miR-200b and miR-200c were higher in patients with FIGO stage III-IV (p = 0.0001, p = 0.008, respectively) including lymph node metastasis (p = 0.0001, p = 0.004, respectively) than FIGO stages I-II. The increased levels of miR-200b and miR-200c were also associated with CA125 values (p = 0.0001, p = 0.0001, respectively) and a shorter overall survival (p = 0.007, p = 0.017, respectively). The levels of exosomes were excessively elevated in EOC patients (p = 0.0001). In all three cohorts, they were positively associated with the serum levels of exosomal miR-373 (p = 0.004), miR-200a (p = 0.0001), miR-200b (p = 0.0001) and miR-200c (p = 0.008). In conclusion, the increased levels of exosomal miR-200b and miR-200c mainly observed in advanced EOC suggest that these microRNAs may be involved in tumor progression. The high concentrations of exosomes in EOC patients imply an excessive, active exosomal secretion in EOC.