Gene expression analyses support fallopian tube epithelium as the cell of origin of epithelial ovarian cancer

Opposing Wnt signals regulate cervical squamocolumnar homeostasis and emergence of metaplasia

The transition zones of the squamous and columnar epithelia constitute hotspots for the emergence of cancer, often preceded by metaplasia, in which one epithelial type is replaced by another. It remains unclear how the epithelial spatial organization is maintained and how the transition zone niche is remodelled during metaplasia. Here we used single-cell RNA sequencing to characterize epithelial subpopulations and the underlying stromal compartment of endo- and ectocervix, encompassing the transition zone. Mouse lineage tracing, organoid culture and single-molecule RNA in situ hybridizations revealed that the two epithelia derive from separate cervix-resident lineage-specific stem cell populations regulated by opposing Wnt signals from the stroma. Using a mouse model of cervical metaplasia, we further show that the endocervical stroma undergoes remodelling and increases expression of the Wnt inhibitor Dickkopf-2 (DKK2), promoting the outgrowth of ectocervical stem cells. Our data indicate that homeostasis at the transition zone results from divergent stromal signals, driving the differential proliferation of resident epithelial lineages.

A systematic review and meta-analysis of higher expression of folate receptor alpha (FOLR1) predicts poor cancer prognosis

Folate receptor alpha (FOLR1), a glycosylphosphatidylinositol-linked protein, is a well characterized folate transporter. However, the prognostic power of FOLR1 in cancer remains controversial. We conducted a meta-analysis to assess the prognostic roles of FOLR1 on different cancers. Twelve studies involving 4471 patients were included in this meta-analysis. The pooled analysis indicated that high FOLR1 significantly predicted poor overall survival (OS) (pooled hazard ratio (HR) = 0.78, 95% confidence interval (CI) = 0.64-0.94, p = 0.009) and the disease-free survival (DFS) (HR = 1.25, 95% CI = 1.07-1.47, p = 0.005). Subgroup analyses based on tumour type found that high FOLR1 level was associated with poor OS in breast cancer (HR = 2.66, 95% CI = 1.54-4.59, p = 0.0005) and endometrial carcinoma (HR = 1.30, 95% CI = 1.05-1.61, p = 0.02). However, FOLR1 has relatively weakly correlation with gender, tumour size and chemotherapy. Additionally, overexpression of FOLR1 was correlated with grade, FIGO stage, vital status and nodule status. The present meta-analysis indicated that the high expression of FOLR1 is associated with the poor survival of cancer patients, which is helpful for the clinical decision-making process.

Fallopian tube initiation of high grade serous ovarian cancer and ovarian metastasis: Mechanisms and therapeutic implications

Ovarian cancer is the most lethal gynecologic malignancy and the fifth leading cause of cancer-related death in women. Although outcomes have improved in recent years, there remains an unmet clinical need to understand the early pathogenesis of ovarian cancer in order to identify new diagnostic approaches and agents of chemoprevention and chemotherapy. While high grade serous ovarian cancer (HGSOC), the most abundant histotype, was initially thought to arise from the ovarian surface epithelium, there is an increasing body of evidence suggesting that HGSOC originates in the fallopian tube. With this new understanding of cell of origin, understanding of disease development requires analysis with a novel perspective. Currently, factors that drive the initiation and migration of dysplastic tubal epithelial cells from the fallopian tube to the ovary are not yet fully defined. These factors include common mutations to fallopian tube epithelial cells, as well as factors originating from both the fallopian tube and ovary which are capable of inducing transformation and dissemination in said cells. Here, we review these changes, their causative agents, and various potential means of intervention.

Both fallopian tube and ovarian surface epithelium are cells-of-origin for high-grade serous ovarian carcinoma

The cell-of-origin of high grade serous ovarian carcinoma (HGSOC) remains controversial, with fallopian tube epithelium (FTE) and ovarian surface epithelium (OSE) both considered candidates. Here, by using genetically engineered mouse models and organoids, we assessed the tumor-forming properties of FTE and OSE harboring the same oncogenic abnormalities. Combined RB family inactivation and Tp53 mutation in Pax8 + FTE caused Serous Tubal Intraepithelial Carcinoma (STIC), which metastasized rapidly to the ovarian surface. These events were recapitulated by orthotopic injection of mutant FTE organoids. Engineering the same genetic lesions into Lgr5 + OSE or OSE-derived organoids also caused metastatic HGSOC, although with longer latency and lower penetrance. FTE- and OSE-derived tumors had distinct transcriptomes, and comparative transcriptomics and genomics suggest that human HGSOC arises from both cell types. Finally, FTE- and OSE-derived organoids exhibited differential chemosensitivity. Our results comport with a dualistic origin for HGSOC and suggest that the cell-of-origin might influence therapeutic response.

Proteomic and Bioinformatic Studies for the Characterization of Response to Pemetrexed in Platinum Drug Resistant Ovarian Cancer

Proteomics and bioinformatics are a useful combined technology for the characterization of protein expression level and modulation associated with the response to a drug and with its mechanism of action. The folate pathway represents an important target in the anticancer drugs therapy. In the present study, a discovery proteomics approach was applied to tissue samples collected from ovarian cancer patients who relapsed after the first-line carboplatin-based chemotherapy and were treated with pemetrexed (PMX), a known folate pathway targeting drug. The aim of the work is to identify the proteomic profile that can be associated to the response to the PMX treatment in pre-treatement tissue. Statistical metrics of the experimental Mass Spectrometry (MS) data were combined with a knowledge-based approach that included bioinformatics and a literature review through ProteinQuest™ tool, to design a protein set of reference (PSR). The PSR provides feedback for the consistency of MS proteomic data because it includes known validated proteins. A panel of 24 proteins with levels that were significantly different in pre-treatment samples of patients who responded to the therapy vs. the non-responder ones, was identified. The differences of the identified proteins were explained for the patients with different outcomes and the known PMX targets were further validated. The protein panel herein identified is ready for further validation in retrospective clinical trials using a targeted proteomic approach. This study may have a general relevant impact on biomarker application for cancer patients therapy selection.

Expression status of folate receptor alpha is a predictor of survival in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has one of the poorest prognosis among malignancies. Thus, the identification of markers useful in developing innovative diagnostic and therapeutic methods is an imperative need. Folate receptor alpha (FRα) has been associated with prognosis in several cancers and has served as a target of novel anti-tumor therapies. However, FRα expression in PDAC and its correlation with the clinical course of the disease has not been thoroughly investigated. In this study, we analyzed FRα expression in 140 PDAC specimens and 7 PDAC cell lines in order to define the significance of FRα expression in PDAC and its potential role as a target for immunotherapy. Immunohistochemical analysis demonstrated that FRα expression intensity was low, intermediate and high in 22(16%), 73(52%) and 45(32%) PDACs, respectively. The staining was located in both membrane and cytoplasm in most cases (123, 88%). Lower FRα expression was associated with cigarette smoking (p<0.001), alcohol consumption (p<0.001), and lymphovascular invasion (p=0.002). Additionally, lower FRα expression was associated with poor overall survival (5-year overall survival: low 13%, intermediate 31%, high 33%; p=0.006). FRα expression (HR=0.61; p=0.03) and Charlson Comorbidity Index (HR=1.16; p=0.01) emerged as independent predictors of survival. The analysis by flow cytometry of 7 PDAC cell lines (AsPC-1, Capan-2, MIA PaCa-2, PANC-1, PDAC2, PDAC3, and PDAC5) demonstrated the highest expression of FRα on the PDAC3 cell line (45%). Therefore, a higher FRα expression is predictive of a favorable prognosis in PDAC and FRα may represent a promising target for novel treatments, including immunotherapy.

Candidate genes and pathways downstream of PAX8 involved in ovarian high-grade serous carcinoma

Understanding the biology and molecular pathogenesis of ovarian epithelial cancer (EOC) is key to developing improved diagnostic and prognostic indicators and effective therapies. Although research has traditionally focused on the hypothesis that high-grade serous carcinoma (HGSC) arises from the ovarian surface epithelium (OSE), recent studies suggest that additional sites of origin exist and a substantial proportion of cases may arise from precursor lesions located in the Fallopian tubal epithelium (FTE). In FTE cells, the transcription factor PAX8 is a marker of the secretory cell lineage and its expression is retained in 96% of EOC. We have recently reported that PAX8 is involved in the tumorigenic phenotype of ovarian cancer cells. In this study, to uncover genes and pathways downstream of PAX8 involved in ovarian carcinoma we have determined the molecular profiles of ovarian cancer cells and in parallel of Fallopian tube epithelial cells by means of a silencing approach followed by an RNA-seq analysis. Interestingly, we highlighted the involvement of pathways like WNT signaling, epithelial-mesenchymal transition, p53 and apoptosis. We believe that our analysis has led to the identification of candidate genes and pathways regulated by PAX8 that could be additional targets for the therapy of ovarian carcinoma.

Histology of the Ovary of the Laying Hen (Gallus domesticus)

The laying hen (Gallus domesticus) is a robust animal model for epithelial ovarian cancer. The use of animal models is critical in identifying early disease markers and developing and testing chemotherapies. We describe the microscopic characteristics of the normally functioning laying hen ovary and proximal oviduct to establish baselines from which lesions associated with ovarian cancer can be more readily identified. Ovaries and oviducts were collected from 18-month-old laying hens (n = 18) and fixed in 10% neutral buffered formalin. Hematoxylin- and eosin-stained sections were examined by light microscopy. Both post-ovulatory follicular regression and atresia of small follicles produce remnant clusters of vacuolated cells with no histological evidence that scar tissue persists. Infiltrates of heterophils are associated with atresia of small follicles, a relationship not previously documented in laying hen ovaries. Because these tissues can be mistaken for cancerous lesions, we present a detailed histological description of remnant Wolffian tissues in the laying hen ovary. Immunohistochemical staining for pancytokeratin produced a positive response in ovarian surface epithelium and staining for vimentin produced a positive response in granulosa cells of follicles. Epithelial cells lining glands of the remnant epoöphoron had a positive response to both pancytokeratin and vimentin, a result also observed in women.

The Effect of Salpingectomy on Ovarian Reserve and Ovarian Function

BACKGROUND

The effect of salpingectomy on ovarian reserve and ovarian function is still a controversial issue, and more investigations are needed.

OBJECTIVE

The aim of this study was to determine the effect of salpingectomy on ovarian reserve and ovarian function.

STUDY STRATEGY

PubMed, Embase, Medline, Web of Knowledge, and the Cochrane trial register were searched.

SELECTION CRITERIA

Studies must have similar study method and be published in English; clear data can be extracted from full test.

DATA COLLECTION AND ANALYSIS

Data were collected and analyzed by Review Manager 5.3.

MAIN RESULTS

A total of 13 studies were eligible. The level of anti-müllerian hormone is lower, and early follicular phase follicle-stimulating hormone is higher in salpingectomy groups. The level of early follicular phase estradiol and the ovarian volume of salpingectomy groups are the same as control. The total dose of follicle-stimulating hormone needed during in vitro fertilization and embryo transfer (IVF-ET) treatment cycles, the number of collected oocytes, and the clinical pregnancy rate are similar in salpingectomy and control groups.

CONCLUSIONS

Salpingectomy does not appear to affect ovarian function, ovarian response to gonadotropin stimulation, or outcome of IVF-ET in the short run. It may, however, impair ovarian reserve in the long run.

Identification of MiR-21-5p as a Functional Regulator of Mesothelin Expression Using MicroRNA Capture Affinity Coupled with Next Generation Sequencing

MicroRNAs (miRNAs) are small non-coding RNAs that regulate mRNA expression mainly by silencing target transcripts via binding to miRNA recognition elements (MREs) in the 3'untranslated region (3'UTR). The identification of bona fide targets is challenging for researchers working on the functional aspect of miRNAs. Recently, we developed a method (miR-CATCH) based on biotinylated DNA antisense oligonucleotides that capture the mRNA of interest and facilitates the characterisation of miRNAs::mRNA interactions in a physiological cellular context. Here, the miR-CATCH technique was applied to the mesothelin (MSLN) gene and coupled with next generation sequencing (NGS), to identify miRNAs that regulate MSLN mRNA and that may be responsible for its increased protein levels found in malignant pleural mesothelioma (MPM). Biotinylated MSLN oligos were employed to isolate miRNA::MSLN mRNA complexes from a normal cell line (Met-5A) which expresses low levels of MSLN. MiRNAs targeting the MSLN mRNA were identified by NGS and miR-21-5p and miR-100-5p were selected for further validation analyses. MiR-21-5p was shown to be able to modulate MSLN expression in miRNA mimic experiments in a panel of malignant and non-malignant cell lines. Further miRNA inhibitor experiments and luciferase assays in Mero-14 cells validated miR-21-5p as a true regulator of MSLN. Moreover, in vitro experiments showed that treatment with miR-21-5p mimic reduced proliferation of MPM cell lines. Altogether, this work shows that the miR-CATCH technique, coupled with NGS and in vitro validation, represents a reliable method to identify native miRNA::mRNA interactions. MiR-21-5p is suggested as novel regulator of MSLN with a possible functional role in cellular growth.

DNA Methylome Analyses Implicate Fallopian Tube Epithelia as the Origin for High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSC) is the most common and lethal form of epithelial ovarian cancer (EOC). Two distinct tissues have been suggested as the tissue of origin: ovarian surface epithelia (OSE) and fallopian tube epithelia (FTE). We hypothesized that the DNA methylome of HGSC should more closely resemble the methylome of its tissue of origin. To this end, we profiled HGSC (n = 10), and patient-matched OSE and FTE (n = 5) primary fresh-frozen tissues, and analyzed the DNA methylome using Illumina 450K arrays (n = 20) and Agilent Sure Select methyl-seq (n = 7). Methylomes were compared using statistical analyses of differentially methylated CpG sites (DMC) and differentially methylated regions (DMR). In addition, methylation was evaluated within a variety of different genomic contexts, including CpG island shores and Homeobox (HOX) genes, due to their roles in tissue specification. Publicly available HGSC methylome data (n = 628) were interrogated to provide additional comparisons with FTE and OSE for validation. These analyses revealed that HGSC and FTE methylomes are significantly and consistently more highly conserved than are HGSC and OSE. Pearson correlations and hierarchal clustering of genes, promoters, CpG islands, CpG island shores, and HOX genes all revealed increased relatedness of HGSC and FTE methylomes. Thus, these findings reveal that the landscape of FTE more closely resembles HGSC, the most common and deadly EOC subtype.

IMPLICATIONS

DNA methylome analyses support the hypothesis that HGSC arise from the fallopian tube and that due to its tissue-specificity and biochemical stability, interrogation of the methylome may be a valuable approach to examine cell/tissue lineage in cancer. Mol Cancer Res; 14(9); 787-94. ©2016 AACR.

Isolation of Circulating Tumor Cells from Multiple Epithelial Cancers with ApoStream(®) for Detecting (or Monitoring) the Expression of Folate Receptor Alpha

This study describes our efforts to further the field of noninvasive diagnostics, specifically in the area of liquid biopsies in oncology. We employed laser scanning cytometry using highly selective antibodies to interrogate circulating tumor cells (CTCs) that were isolated using ApoStream^® technology to identify folate receptor alpha (FRα)-positive cells. We demonstrate that FRα⁺ CTCs can be isolated from patients with metastatic cancers, including NSCLC adenocarcinoma, breast cancer, and ovarian cancer, whereas squamous cell lung cancer and normal healthy controls were devoid of FRα⁺ CTCs. We believe that the developed methodology will have applications in both the diagnosis and the monitoring of FRα-expressing cancers. Folate receptor alpha (FRα) expression may have utility as a potential diagnostic and therapeutic target in solid tumors. As tissue samples are not always available for patient screening, this study evaluated a noninvasive assay in CTCs from blood samples to detect FRα expression. The presence of FRα⁺ CTCs enriched using ApoStream^® and detected using laser capture cytometry was evaluated in blood samples from cancer patients [NSCLC adenocarcinoma (n = 14), breast cancer (n = 20), ovarian cancer (n = 6), and squamous lung cancer patients (n = 6)] and healthy subjects (n = 20). The data demonstrated that FRα⁺ CTCs were detected in blood from NSCLC adenocarcinoma, breast, and ovarian cancer patients, whereas squamous cell lung cancer patients and normal healthy controls lacked FRα⁺ CTCs as previously known. We demonstrate that CTCs captured using ApoStream^® can be used to detect FRα⁺ CTCs and may have clinical utility as a real-time liquid biopsy for assessing FRα levels in cancer patients.

Human Leukocyte Antigen-Presented Macrophage Migration Inhibitory Factor Is a Surface Biomarker and Potential Therapeutic Target for Ovarian Cancer

T cells recognize cancer cells via HLA/peptide complexes, and when disease overtakes these immune mechanisms, immunotherapy can exogenously target these same HLA/peptide surface markers. We previously identified an HLA-A2-presented peptide derived from macrophage migration inhibitory factor (MIF) and generated antibody RL21A against this HLA-A2/MIF complex. The objective of the current study was to assess the potential for targeting the HLA-A2/MIF complex in ovarian cancer. First, MIF peptide FLSELTQQL was eluted from the HLA-A2 of the human cancerous ovarian cell lines SKOV3, A2780, OV90, and FHIOSE118hi and detected by mass spectrometry. By flow cytometry, RL21A was shown to specifically stain these four cell lines in the context of HLA-A2. Next, partially matched HLA-A*02:01+ ovarian cancer (n = 27) and normal fallopian tube (n = 24) tissues were stained with RL21A by immunohistochemistry to assess differential HLA-A2/MIF complex expression. Ovarian tumor tissues revealed significantly increased RL21A staining compared with normal fallopian tube epithelium (P < 0.0001), with minimal staining of normal stroma and blood vessels (P < 0.0001 and P < 0.001 compared with tumor cells) suggesting a therapeutic window. We then demonstrated the anticancer activity of toxin-bound RL21A via the dose-dependent killing of ovarian cancer cells. In summary, MIF-derived peptide FLSELTQQL is HLA-A2-presented and recognized by RL21A on ovarian cancer cell lines and patient tumor tissues, and targeting of this HLA-A2/MIF complex with toxin-bound RL21A can induce ovarian cancer cell death. These results suggest that the HLA-A2/MIF complex should be further explored as a cell-surface target for ovarian cancer immunotherapy.

A Synthetic Lethality Screen Using a Focused siRNA Library to Identify Sensitizers to Dasatinib Therapy for the Treatment of Epithelial Ovarian Cancer

Molecular targeted therapies have been the focus of recent clinical trials for the treatment of patients with recurrent epithelial ovarian cancer (EOC). The majority have not fared well as monotherapies for improving survival of these patients. Poor bioavailability, lack of predictive biomarkers, and the presence of multiple survival pathways can all diminish the success of a targeted agent. Dasatinib is a tyrosine kinase inhibitor of the Src-family kinases (SFK) and in preclinical studies shown to have substantial activity in EOC. However, when evaluated in a phase 2 clinical trial for patients with recurrent or persistent EOC, it was found to have minimal activity. We hypothesized that synthetic lethality screens performed using a cogently designed siRNA library would identify second-site molecular targets that could synergize with SFK inhibition and improve dasatinib efficacy. Using a systematic approach, we performed primary siRNA screening using a library focused on 638 genes corresponding to a network centered on EGFR, HER2, and the SFK-scaffolding proteins BCAR1, NEDD9, and EFS to screen EOC cells in combination with dasatinib. We followed up with validation studies including deconvolution screening, quantitative PCR to confirm effective gene silencing, correlation of gene expression with dasatinib sensitivity, and assessment of the clinical relevance of hits using TCGA ovarian cancer data. A refined list of five candidates (CSNK2A1, DAG1, GRB2, PRKCE, and VAV1) was identified as showing the greatest potential for improving sensitivity to dasatinib in EOC. Of these, CSNK2A1, which codes for the catalytic alpha subunit of protein kinase CK2, was selected for additional evaluation. Synergistic activity of the clinically relevant inhibitor of CK2, CX-4945, with dasatinib in reducing cell proliferation and increasing apoptosis was observed across multiple EOC cell lines. This overall approach to improving drug efficacy can be applied to other targeted agents that have similarly shown poor clinical activity.

Clinical management of patients at inherited risk for gynecologic cancer

PURPOSE OF REVIEW

As more women with an inherited increased risk of gynecologic cancer are identified, the clinician will be challenged to counsel these women on risk-reducing strategies.

RECENT FINDINGS

Although there are some recent studies that show potential for ovarian cancer surveillance strategies, there remains no definitive evidence that surveillance leads to a stage shift or a reduction in mortality. Recent studies support the following conclusions: first, oral contraceptive use reduces ovarian cancer risk without significantly increasing breast cancer risk, second, salpingo-oophorectomy leads to a reduction in ovarian cancer, breast cancer, and overall mortality for women who are carriers of BRCA1 and BRCA2 mutations, and third, the 'ovarian cancers' associated with BRCA mutations actually include fallopian tube and peritoneal cancer and may have a precursor lesion in the fallopian tube; this observation has prompted the provocative suggestion of removing the fallopian tube to reduce ovarian cancer risk.

SUMMARY

Because of the interplay between the hormonal impact of ovarian function on breast cancer risk, the risk reduction associated with oophorectomy, and the impact of early menopause on other health outcomes, an integrated multidisciplinary approach is required to aid in the increasingly complex decisions faced by women with high inherited risk of developing gynecologic cancers.

The role of human epididymis protein 4 in the diagnosis of epithelial ovarian cancer

PURPOSE

Epithelial ovarian cancer is one of the most lethal female genital tract cancers. Early diagnosis of EOC would benefit the patients a lot. Human epididymis protein 4 (HE4) has been regarded as a new powerful biomarker in diagnosis of EOC; we hope to obtain system knowledge of HE4 and understand the role of HE4 in diagnosis of epithelial ovarian cancer (EOC).

METHODS

We searched Pubmed, Embase, Medline, and Chinese National Knowledge Infrastructure (CNKI) for articles that included HE4's origin, characteristics, detection methods, clinical efficacy alone or combined with CA125, the risk of malignancy index, and the risk of ovarian malignancy algorithm. The diagnostic performance for the EOC and the role in the recurrence and procession in EOC were also discussed.

RESULTS

We got 83 most related articles and found that there were significantly difference existing among the studies, such as the clinical characteristics of patients, the methodology for measuring HE4, the different cut-offs for HE4 and so on.

CONCLUSION

HE4 is a promising biomarker for the early diagnosis of EOC. However, each lab should establish its own reference internal of HE4.

Systematic transcriptome analysis reveals tumor-specific isoforms for ovarian cancer diagnosis and therapy

Tumor-specific molecules are needed across diverse areas of oncology for use in early detection, diagnosis, prognosis and therapy. Large and growing public databases of transcriptome sequencing data (RNA-seq) derived from tumors and normal tissues hold the potential of yielding tumor-specific molecules, but because the data are new they have not been fully explored for this purpose. We have developed custom bioinformatic algorithms and used them with 296 high-grade serous ovarian (HGS-OvCa) tumor and 1,839 normal RNA-seq datasets to identify mRNA isoforms with tumor-specific expression. We rank prioritized isoforms by likelihood of being expressed in HGS-OvCa tumors and not in normal tissues and analyzed 671 top-ranked isoforms by high-throughput RT-qPCR. Six of these isoforms were expressed in a majority of the 12 tumors examined but not in 18 normal tissues. An additional 11 were expressed in most tumors and only one normal tissue, which in most cases was fallopian or colon. Of the 671 isoforms, the topmost 5% (n = 33) ranked based on having tumor-specific or highly restricted normal tissue expression by RT-qPCR analysis are enriched for oncogenic, stem cell/cancer stem cell, and early development loci--including ETV4, FOXM1, LSR, CD9, RAB11FIP4, and FGFRL1. Many of the 33 isoforms are predicted to encode proteins with unique amino acid sequences, which would allow them to be specifically targeted for one or more therapeutic strategies--including monoclonal antibodies and T-cell-based vaccines. The systematic process described herein is readily and rapidly applicable to the more than 30 additional tumor types for which sufficient amounts of RNA-seq already exist.

Expression of folate receptors alpha and beta in normal and cancerous gynecologic tissues: correlation of expression of the beta isoform with macrophage markers

Background

Folate receptor alpha (FOLR1/FRA) is expressed in a number of epithelial cancers and in particular epithelial ovarian cancer (EOC), especially of the serous histotype. Recent studies have shown that EOC originates from the fallopian tube fimbriae rather than from epithelial cells lining the ovary. We have previously shown by immunohistochemistry a strong correlation between FRA expression in EOC and normal and fallopian adenocarcinoma. Folate receptor beta (FOLR2/FRB) has been described to be expressed by macrophages both in inflammatory disorders and certain epithelial cancers. Given the high sequence identity of these two folate receptor family members we sought to investigate the architectural and cell-specific expression of these two receptors in gynecologic tissues.

Methods

RNA scope, a novel chromogenic in situ hybridization assay tool, was used to examine expression of the alpha (FOLR1) and beta (FOLR2) isoforms of folate receptor relative to each other as well as to the macrophage markers CD11b and CD68, in samples of normal fallopian tube and fallopian adenocarcinoma as well as normal ovary and EOC.

Results

We demonstrated expression of both FOLR1 and FOLR2 in EOC, normal fallopian tube and fallopian adenocarcinoma tissue while very little expression of either marker was observed in normal ovary. Furthermore, FOLR2 was shown to be expressed almost exclusively in macrophages, of both the M1 and M2 lineages, as determined by co-expression of CD11b and/or CD68, with little or no expression in epithelial cells.

Conclusions

These findings further substantiate the hypothesis that the cell of origin of EOC is tubal epithelium and that the beta isoform of folate receptor is primarily restricted to macrophages. Further, macrophages expressing FOLR2 may represent tumor associated or infiltrating macrophages (TAMs) in epithelial cancers.

Immunohistological insight into the correlation between neuropilin-1 and epithelial-mesenchymal transition markers in epithelial ovarian cancer

The mechanism by which neuropilin-1 (NRP-1) induces malignancy in Epithelial Ovarian Cancer (EOC) is still unknown. This study is the first to demonstrate the relationship between NRP-1 expression and EMT markers vimentin, N-cadherin, E-cadherin and Slug. We used tissue microarrays containing the three main subtypes of EOC tumors: serous, mucinous cystadenocarcinoma and endometrioid adenocarcinoma and representative cases retrieved from our pathology archives. Immunohistochemistry was performed to detect the expression levels and location of NRP-1 and the aforementioned EMT proteins. NRP-1 was mainly expressed on cancer cells but not in normal ovarian surface epithelium (OSE). The Immunoreactive Scoring (IRS) values revealed that the expression of NRP-1, Slug and E-cadherin in the malignant subtypes of ovarian tissues was significantly higher (5.18 ± 0.64, 4.84 ± 0.7, 4.98 ± 0.68, respectively) than their expression in the normal and benign tissues (1.04 ± 0.29, 0.84 ± 0.68, 1.71 ± 0.66, respectively), with no significant differences among the studied subtypes. Vimentin was expressed in the cancer cell component of 43% of tumors and it was exclusively localized in the stroma of all mucinous tumors. The Spearman's rho value indicated that NRP-1 is positively related to the EMT markers E-cadherin and Slug. This notion might indicate that NRP-1 is a partner in the EMT process in EOC tumors.

Prophylactic bilateral salpingectomy as a prevention strategy in women at high-risk of ovarian cancer: a mini-review

Risk-reducing bilateral salpingo-oophorectomy is a proven strategy to reduce the risk of serous ovarian cancer associated with germline BRCA mutations. It is most effective when performed before natural menopause, but it will render a woman prematurely menopausal. The tubal hypothesis of serous ovarian cancer brings with it the possibility of the alternative surgical approach in younger women comprising of risk-reducing bilateral salpingectomy while conserving their ovaries until nearer the age of natural menopause, when a delayed bilateral oophorectomy can be performed. This article will review the evidence behind the tubal hypothesis of serous ovarian cancer and explore the opportunities for translating this into clinical cancer prevention practice.

Refractory fallopian tube carcinoma - current perspectives in pathogenesis and management

Fallopian tube carcinoma (FTC) is considered a rare malignancy, but recent evidence shows that its incidence may have been underestimated. Risk-reducing salpingo-oophorectomy (RRSO) in breast cancer susceptibility gene (BRCA)-positive women has provided a unique opportunity to study the pathogenesis of FTC and ovarian carcinomas. Newer data now suggest that most high-grade serous cancers of the ovary originate in the fimbrial end of the fallopian tube. Due to the presumed rarity of FTC, most current and more recent ovarian cancer clinical trials have now included patients with FTC. The treatment guidelines recommend similar overall management and that the same chemotherapy regimens be used for epithelial ovarian cancers and FTC.

Analysis of the levels of lysine-specific demethylase 1 (LSD1) mRNA in human ovarian tumors and the effects of chemical LSD1 inhibitors in ovarian cancer cell lines

BACKGROUND

Lysine-specific demethylase 1 (LSD1, also known as KDM1A and AOF2) is a chromatin-modifying activity that catalyzes the removal of methyl groups from lysine residues in histone and non-histone proteins, regulating gene transcription. LSD1 is overexpressed in several cancer types, and chemical inhibition of the LSD1 activity has been proposed as a candidate cancer therapy. Here, we examine the levels of LSD1 mRNA in human ovarian tumors and the cytotoxicity of several chemical LSD1 inhibitors in a panel of ovarian cancer cell lines.

METHODS

We measured LSD1 mRNA levels in a cohort of n = 177 normal and heterogeneous tumor specimens by quantitative real time-PCR (qRT-PCR). Tumors were classified by FIGO stage, FIGO grade, and histological subtypes. We tested the robustness of our analyses in an independent cohort of n = 573 serous tumor specimens (source: TCGA, based on microarray). Statistical analyses were based on Kruskal-Wallis/Dunn's and Mann Whitney tests. Changes in LSD1 mRNA levels were also correlated with transcriptomic alterations at genome-wide scale. Effects on cell viability (MTS/PMS assay) of six LSD1 inhibitors (pargyline, TCP, RN-1, S2101, CAS 927019-63-4, and CBB1007) were also evaluated in a panel of ovarian cancer cell lines (SKOV3, OVCAR3, A2780 and cisplatin-resistant A2780cis).

RESULTS

We found moderate but consistent LSD1 mRNA overexpression in stage IIIC and high-grade ovarian tumors. LSD1 mRNA overexpression correlated with a transcriptomic signature of up-regulated genes involved in cell cycle and down-regulated genes involved in the immune/inflammatory response, a signature previously observed in aggressive tumors. In fact, some ovarian tumors showing high levels of LSD1 mRNA are associated with poor patient survival. Chemical LSD1 inhibition induced cytotoxicity in ovarian cancer lines, which roughly correlated with their reported LSD1 inhibitory potential (RN-1,S2101 >> pargyline,TCP).

CONCLUSIONS

Our findings may suggest a role of LSD1 in the biology of some ovarian tumors. It is of special interest to find a correlation of LSD1 mRNA overexpression with a transcriptomic signature relevant to cancer. Our findings, therefore, prompt further investigation of the role of LSD1 in ovarian cancer, as well as the study of its enzymatic inhibition in animal models for potential therapeutic purposes in the context of this disease.