Estrogen biosynthesis and action in ovarian cancer

Steroidomics for the Prevention, Assessment, and Management of Cancers: A Systematic Review and Functional Analysis

Steroidomics, an analytical technique for steroid biomarker mining, has received much attention in recent years. This systematic review and functional analysis, following the PRISMA statement, aims to provide a comprehensive review and an appraisal of the developments and fundamental issues in steroid high-throughput analysis, with a focus on cancer research. We also discuss potential pitfalls and proposed recommendations for steroidomics-based clinical research. Forty-five studies met our inclusion criteria, with a focus on 12 types of cancer. Most studies focused on cancer risk prediction, followed by diagnosis, prognosis, and therapy monitoring. Prostate cancer was the most frequently studied cancer. Estradiol, dehydroepiandrosterone, and cortisol were mostly reported and altered in at least four types of cancer. Estrogen and estrogen metabolites were highly reported to associate with women-related cancers. Pathway enrichment analysis revealed that steroidogenesis; androgen and estrogen metabolism; and androstenedione metabolism were significantly altered in cancers. Our findings indicated that estradiol, dehydroepiandrosterone, cortisol, and estrogen metabolites, among others, could be considered oncosteroids. Despite noble achievements, significant shortcomings among the investigated studies were small sample sizes, cross-sectional designs, potential confounding factors, and problematic statistical approaches. More efforts are required to establish standardized procedures regarding study design, analytical procedures, and statistical inference.

Apelin abrogates the stimulatory effects of 17β-estradiol and insulin-like growth factor-1 on proliferation of epithelial and granulosa ovarian cancer cell lines via crosstalk between APLNR and ERα/IGF1R

Apelin and chemerin are adipocytokines that play important roles in many physiological and pathological processes throughout the body. Our previous study demonstrated that these two adipokines are expressed and secreted by epithelial and granulosa cancer cell lines. 17β-estradiol (E2) and insulin-like growth factor-1 (IGF-1) are important regulators of ovarian functions, and their roles are well known. This study investigated whether apelin and chemerin regulate proliferation and apoptosis of epithelial (OVCAR-3) and granulosa (COV434) ovarian cancer cell lines by interacting with E2 and IGF-1. Apelin and chemerin did not affect caspase-3 activation in either cell line. However, apelin abrogated the stimulatory effects of E2 on proliferation of OVCAR-3 cells and of IGF-1 on proliferation of COV434 cells independently of ERK1/2 and PI3K via crosstalk of apelin receptor with estrogen receptor alpha and IGF-1 receptor, respectively.

Estrogens Counteract Platinum-Chemosensitivity by Modifying the Subcellular Localization of MDM4

Estrogen activity towards cancer-related pathways can impact therapeutic intervention. Recent omics data suggest possible crosstalk between estrogens/gender and MDM4, a key regulator of p53. Since MDM4 can either promote cell transformation or enhance DNA damage-sensitivity, we analysed in vivo impact of estrogens on both MDM4 activities. In Mdm4 transgenic mouse, Mdm4 accelerates the formation of fibrosarcoma and increases tumor sensitivity to cisplatin as well, thus confirming in vivo Mdm4 dual mode of action. Noteworthy, Mdm4 enhances chemo- and radio-sensitivity in male but not in female animals, whereas its tumor-promoting activity is not affected by mouse gender. Combination therapy of transgenic females with cisplatin and fulvestrant, a selective estrogen receptor degrader, was able to recover tumor cisplatin-sensitivity, demonstrating the relevance of estrogens in the observed sexual dimorphism. Molecularly, estrogen receptor-α alters intracellular localization of MDM4 by increasing its nuclear fraction correlated to decreased cell death, in a p53-independent manner. Importantly, MDM4 nuclear localization and intra-tumor estrogen availability correlate with decreased platinum-sensitivity and apoptosis and predicts poor disease-free survival in high-grade serous ovarian carcinoma. These data demonstrate estrogen ability to modulate chemo-sensitivity of MDM4-expressing tumors and to impinge on intracellular trafficking. They support potential usefulness of combination therapy involving anti-estrogenic drugs.

Protein-Protein Interaction Network Analysis Reveals Several Diseases Highly Associated with Polycystic Ovarian Syndrome

Based on clinical observations, women with polycystic ovarian syndrome (PCOS) are prone to developing several other diseases, such as metabolic and cardiovascular diseases. However, the molecular association between PCOS and these diseases remains poorly understood. Recent studies showed that the information from protein-protein interaction (PPI) network analysis are useful in understanding the disease association in detail. This study utilized this approach to deepen the knowledge on the association between PCOS and other diseases. A PPI network for PCOS was constructed using PCOS-related proteins (PCOSrp) obtained from PCOSBase. MCODE was used to identify highly connected regions in the PCOS network, known as subnetworks. These subnetworks represent protein families, where their molecular information is used to explain the association between PCOS and other diseases. Fisher's exact test and comorbidity data were used to identify PCOS-disease subnetworks. Pathway enrichment analysis was performed on the PCOS-disease subnetworks to identify significant pathways that are highly involved in the PCOS-disease associations. Migraine, schizophrenia, depressive disorder, obesity, and hypertension, along with twelve other diseases, were identified to be highly associated with PCOS. The identification of significant pathways, such as ribosome biogenesis, antigen processing and presentation, and mitophagy, suggest their involvement in the association between PCOS and migraine, schizophrenia, and hypertension.

Substantial Effect of Fenugreek Seeds Aqueous Extract on Serum Estradiol Level in Ovarian Hyperstimulation Syndrome Rat Model

Objectives

Estradiol (E2) plays an important role in the pathophysiology of ovarian hyperstimulation syndrome (OHSS). This study aimed to evaluate the effect of fenugreek seed aqueous (FSA) extract on serum E2 levels in a rat model of OHSS.

Methods

A total of 34 female Sprague Dawley rats, aged 18 days old, weighing 40 to 45 g, were randomly divided into negative control, positive control, and treatment groups. A daily dose of 1500 mg/kg per body weight of FSA extract was administrated orally to rats in the treatment group for 13 days. On day eight of the study, OHSS was induced in both positive control and treated groups by subcutaneous injection of pregnant mare’s serum gonadotropin 50 IU for four consecutive days, followed by human chorionic gonadotropin 25 IU on the fifth day. The effect of FSA extract was evaluated by measuring the concentration of serum E2 using the enzyme-linked immunosorbent assay.

Results

FSA extract reduced serum E2 level significantly in the treated OHSS model (p-value < 0.050) compared to the positive control group.

Conclusions

The finding has important implications on the development of female infertility adjuvant drugs for safe assisted reproduction technology cycles in terms of OHSS prevention.

Role of phospho-ezrin in differentiating thyroid carcinoma

Comprehensive theory explaining the relationship between estrogen (E2) and ezrin in metastasis of thyroid cancer remains non-elicited. In vitro results revealed that E2 could stimulate the expression and phosphorylation of ezrin in a time and dose dependent manner. Our data clearly showed that E2 enhanced the migration and invasion of cells, which was reversed by the transfection of cells with ezrin specific siRNA. Further, we observed that Phosphoinositide 3-kinase (PI3K) ROCK-2 are among the kinases responsible for E2 induced phosphorylation of ezrin. Clinical validation of ezrin/phospho-ezrin revealed that phospho-ezrin was intensely expressed in follicular thyroid carcinoma (FTC) and follicular variant of papillary thyroid carcinoma (FVPTC), while it was completely absent in follicular adenoma (FA) lesions in which the differentiation of the follicular neoplasms remains subtle. When histology of different carcinomas is correlated with benign FA with respect to phospho-ezrin, we observed that the marker was highly significant (p = 0.0001). 100% sensitivity, specificity and diagnostic accuracy of the above marker in the histological association of FTC, FVPTC with FA, enables us to suggest phospho-ezrin as a diagnostic marker to differentiate the follicular neoplasms. These data are the first to suggest the dynamic regulation of ezrin phosphorylation during metastasis in FTC.

Future Aspects for Cannabinoids in Breast Cancer Therapy

Cannabinoids (CBs) from Cannabis sativa provide relief for tumor-associated symptoms (including nausea, anorexia, and neuropathic pain) in the palliative treatment of cancer patients. Additionally, they may decelerate tumor progression in breast cancer patients. Indeed, the psychoactive delta-9-tetrahydrocannabinol (THC), non-psychoactive cannabidiol (CBD) and other CBs inhibited disease progression in breast cancer models. The effects of CBs on signaling pathways in cancer cells are conferred via G-protein coupled CB-receptors (CB-Rs), CB1-R and CB2-R, but also via other receptors, and in a receptor-independent way. THC is a partial agonist for CB1-R and CB2-R; CBD is an inverse agonist for both. In breast cancer, CB1-R expression is moderate, but CB2-R expression is high, which is related to tumor aggressiveness. CBs block cell cycle progression and cell growth and induce cancer cell apoptosis by inhibiting constitutive active pro-oncogenic signaling pathways, such as the extracellular-signal-regulated kinase pathway. They reduce angiogenesis and tumor metastasis in animal breast cancer models. CBs are not only active against estrogen receptor-positive, but also against estrogen-resistant breast cancer cells. In human epidermal growth factor receptor 2-positive and triple-negative breast cancer cells, blocking protein kinase B- and cyclooxygenase-2 signaling via CB2-R prevents tumor progression and metastasis. Furthermore, selective estrogen receptor modulators (SERMs), including tamoxifen, bind to CB-Rs; this process may contribute to the growth inhibitory effect of SERMs in cancer cells lacking the estrogen receptor. In summary, CBs are already administered to breast cancer patients at advanced stages of the disease, but they might also be effective at earlier stages to decelerate tumor progression.

Estrogen sulfotransferase in the metabolism of estrogenic drugs and in the pathogenesis of diseases

INTRODUCTION

Biotransformation is important in the metabolism of endobiotics and xenobiotics. This process comprises the activity of phase I and phase II enzymes. Estrogen sulfotransferase (SULT1E1 or EST) is a phase II conjugating enzyme that belongs to the family of cytosolic sulfotransferases. The expression of SULT1E1 can be detected in many tissues, including the liver. SULT1E1 catalyzes the transfer of a sulfate group from 3'-phosphoadenosine-5'-phosphosulfate (PAPS) to any available hydroxyl group in estrogenic molecules. The substrates of SULT1E1 include the endogenous and synthetic estrogens. Upon SULT1E1-mediated sulfation, the hydrosolubility of estrogens increases, preventing the binding between the sulfated estrogens and the estrogen receptor (ER). This sulfated state of the estrogens is not irreversible, as the steroid sulfatase (STS) can convert sulfoconjugated estrogens to free estrogens. The expression of SULT1E1 is inducible by several diseases that involve tissue inflammation, such as type 2 diabetes, sepsis, and ischemia-reperfusion injury. Areas covered: This systematic literature review aims to summarize the role of SULT1E1 in the metabolism of estrogenic drugs and xenobiotics, and the role of SULT1E1 in the pathogenesis of several diseases, including cancer, metabolic disease, sepsis, liver injury, and cystic fibrosis. Meanwhile, ablation or pharmacological inhibition of SULT1E1 can affect the outcomes of the aforementioned diseases. Expert opinion: In addition to its role in metabolizing estrogenic drugs, SULT1E1 is unexpectedly being unveiled as a mediator for the disease effect on estrogen metabolism and homeostasis. Meanwhile, because the expression and activity of SULT1E1 can affect the outcome of diseases, the same sulfotransferase and the reversing enzymes STS can be potential therapeutic targets to prevent or manage diseases. Accumulating evidence suggest that the physiological and pathophysiological effects of SULT1E1 can be estrogen-independent and it is necessary to elucidate what other possible substrates may be recognized by the enzyme. Moreover, human studies are paramount to confirm the human relevance of the animal studies.

Genetic and epigenetic characteristics in ovarian tissues from polycystic ovary syndrome patients with irregular menstruation resemble those of ovarian cancer

BACKGROUND

Irregular menstruation is clinically associated with an increased risk for ovarian cancer and disease-related mortality. This relationship remains poorly understood, and a mechanism explaining it has yet to be described.

METHODS

Ovarian tissues from women with polycystic ovary syndrome (PCOS) and regular menstruation (n = 10) or irregular menstruation (n = 10) were subjected to DNA methylation sequencing, real-time PCR array, whole-exome sequencing, and bioinformatics analysis.

RESULTS

We demonstrated that ovarian tissue from PCOS patients with irregular menstruation displayed global DNA hypomethylation, as well as hypomethylation at several functionally and oncologically significant regions. Furthermore, we showed that several cancer-related genes were aberrantly expressed in ovarian tissue from patients with irregular menstruation, and that their mRNA and microRNA profiles shared appreciable levels of coincidence with those from ovarian cancer tissue. We identified multiple point mutations in both the BRCA1 and MLH1 genes in patients with irregular menstruation, and predicted the potential pathogenicity of these mutations using bioinformatics analyses.

CONCLUSIONS

Due to the nature of ovarian cancer, it is important to broaden our understanding of the pathogenesis and risk factors of the disease. Herein, we provide the first description of a genetic and epigenetic basis for the clinical relationship between irregular menstruation and an increased risk for ovarian cancer.

Diet, menopause and the risk of ovarian, endometrial and breast cancer

Menopause, the permanent cessation of the menstrual cycle, marks the end of a woman's reproductive lifespan. In addition to changes in sex hormone levels associated with menopause, its timing is another predictor of future health outcomes such as duration of the presence of vasomotor symptoms (VMS) and the risk of hormone-related cancers. With ageing of the population, it is estimated that worldwide 1·2 billion women will be menopausal by the year 2030. Previously the effects of reproductive factors (e.g. parity, age at menarche, pregnancy) and socio-demographic factors on intermediate and long-term health outcomes of menopause have been widely documented. However, little is known about whether diet could have an impact on these. Therefore, we review current evidence on the associations of diet with menopause, presence of VMS and the risk of hormone-related cancers such as ovarian, endometrial and breast cancer. Dietary factors could influence the lifespan of the ovaries and sex-hormones levels, hence the timing of natural menopause. Few studies reported an association between diet, in particular soya consumption, and a reduced risk of VMS. Sustained oestrogen exposure has been associated with a higher risk of hormone-related cancers and thus high-fat and meat diets have been linked with an increased risk of these cancers. However, to better understand the mechanistic pathways involved and to make stronger conclusions for these relationships, further studies investigating the associations of dietary intakes and dietary patterns with menopause, presence of VMS and the risk of hormone-related cancers are required.

Persistent endocrine-disrupting chemicals found in human follicular fluid stimulate the proliferation of granulosa tumor spheroids via GPR30 and IGF1R but not via the classic estrogen receptors

Epidemiological studies have found that women have detectable levels of organic pollutants such as hexachlorobenzene (HCB), 2,2-dichlorodiphenyldichloroethylene (p,p'-DDE), polychlorinated biphenyl 153 (PCB153), perfluorooctanoate (PFOA), and perfluorooctane sulfonate (PFOS) in their follicular fluid. Thus, these compounds may directly affect the function of granulosa cells within the ovary and may promote granulosa cell tumor (GCT) progression. Two human GCT cell lines, COV434 and KGN, have been used as in vitro model systems to represent juvenile (JGCT) and adult (AGCT) GCT subtypes, respectively. In this study, we found that basal expression of estrogen receptor 1 (ESR1), estrogen receptor 2 (ESR2), and insulin-like growth factor 1 receptor (IGF1R) was higher in the AGCT subtype than in the JGCT subtype. All of the compounds acted as mitogenic factors at low nanomolar concentrations in the JGCT and AGCT forms of GCT. Interestingly, PFOA, PFOS, and HCB stimulated cell proliferation through IGF1R, whereas p,p'-DDE acted through GPR30. Moreover, a mixture of the five compounds also significantly stimulated granulosa cell proliferation; however, the observed effect was lower than predicted. Interestingly, the proliferative effect of a mixture of these compounds was dependent on IGF1R and GPR30 but independent of the classic estrogen receptors. Taken together, our results demonstrate for the first time that mixtures of persistent organic pollutants present in follicular fluids may induce granulosa tumor progression through IGF1R and GPR30 by acting as mitogenic factors in granulosa cells.

Cancer of Reproductive System: Receptors and Targeting Strategies

Carcinogenesis in the different organs of the reproductive system, particularly, prostate, ovarian, and cervical tissues, involves aberrant expression of various physiological receptors belonging to different superfamilies. This chapter provides insights into the physiological receptors that are associated with the genesis, progression, metastasis, management, as well as the prognosis of the cancers of the male and female reproductive systems. It also highlights the structural and binding characteristics of the highly predominant receptors, namely, androgen, estrogen, progesterone, and gonadotropin-releasing hormone (GnRH) receptors, which are overexpressed in these cancers and discusses various strategies to target them.

The role of menopausal hormone therapy in women with or at risk of ovarian and breast cancers: Misconceptions and current directions

For women who are candidates for menopausal hormone therapy (MHT), estrogen can provide relief from symptomatic menopause, decrease rates of chronic illnesses, and improve health-related quality of life. However, confusion surrounds the evidence regarding the impact of exogenous estrogen and progesterone on the breast and ovary. Available data regarding the risks of MHT (estrogen and/or progestin) related to the development of breast and ovarian cancer are often inconsistent or incomplete. Modern molecular and genetic techniques have improved our understanding of the heterogeneity of breast and ovarian cancer. This enhanced understanding of the disease has impacted our understanding of carcinogenesis. Treatment options have evolved to be more targeted toward hormonal therapy for certain subtypes of disease, whereas cytotoxic chemotherapy remains the standard for other histological and molecular subtypes. The role of MHT in the breast and ovarian cancer survivor, as well as women who are at high risk for the development of hereditary breast and ovarian cancer, remains controversial despite evidence that this treatment can improve quality of life and survival outcomes. Through this article, we examine the evidence for and against the use of MHT with a focus on women who have or are at high risk for breast and ovarian cancer.

Patient-derived xenograft mouse models: A high fidelity tool for individualized medicine

Patient-derived xenograft (PDX) mouse models involve the direct transfer of fresh human tumor samples into immunodeficient mice following surgical resection or other medical operations. Gene expression in tumors may be maintained by serial passages of tumors from mouse to mouse. These models aid research into tumor biology and pharmacology without manual manipulation of cell cultures in vitro. and are widely used in individualized cancer therapy/translational medicine, drug development and coclinical trials. PDX models exhibit higher predictive values for clinical outcomes than cell line-derived xenograft models and genetically engineered mouse models. However, PDX models are associated with certain challenges in clinical application. The present study reviewed current collections of PDX models and assessed the challenges and future directions of this field.

Mechanisms for estrogen receptor expression in human cancer

Estrogen is a steroid hormone that has critical roles in reproductive development, bone homeostasis, cardiovascular remodeling and brain functions. However, estrogen also promotes mammary, ovarian and endometrial tumorigenesis. Estrogen antagonists and drugs that reduce estrogen biosynthesis have become highly successful therapeutic agents for breast cancer patients. The effects of estrogen are largely mediated by estrogen receptor (ER) α and ERβ, which are members of the nuclear receptor superfamily of transcription factors. The mechanisms underlying the aberrant expression of ER in breast cancer and other types of human tumors are complex, involving considerable alternative splicing of ERα and ERβ, transcription factors, epigenetic and post-transcriptional regulation of ER expression. Elucidation of mechanisms for ER expression may not only help understand cancer progression and evolution, but also shed light on overcoming endocrine therapy resistance. Herein, we review the complex mechanisms for regulating ER expression in human cancer.

Formononetin, an isoflavone from Astragalus membranaceus inhibits proliferation and metastasis of ovarian cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Astragalus membranaceus which was originally described in the Shennong's Classic of Materia Medica, the earliest complete Pharmacopoeia of China written from the Warring States Period to Han Dynasty, has been widely used in Chinese medicine for > 2000 years, especially in the prescription of curing cancer. A. membranaceus has various bioactivities, such as anti-tumor, anti-viral, anti-oxidant, anti-diabetes, anti-inflammation, anti-atherosclerosis, immunomodulation, hepatoprotection, hematopoiesis, neuroprotection and so on. As an important component of A. membranaceus, whether formononetin has a close relationship with its tumor-inhibiting effect on ovarian cancer cell has been investigated.

AIM OF STUDY

The present study aimed to demonstrate the anti-proliferation, anti- migration and invasion effects of formononetin on ovarian cancer cells and further explore the underlying molecular mechanisms associated with apoptosis, migration and invasion.

MATERIALS AND METHODS

MTT assay was performed to detect the viability of ovarian cancer cells. DAPI staining, Annexin-V assay and assay for mitochondrial membrane potential detected the apoptosis of ovarian cancer cells treated by formononetin. The migration and invasion of ovarian cancer cells which exposed to formononetin were detected by scratch assay and transwell assay. Meanwhile, the protein-level changes of in ovarian cancer cells treated by formononetin were assessed by western blot analysis.

RESULTS

MTT assays indicated that cell viability significantly decreased in ovarian cancer cells treated with formononetin. DAPI staining, Annexin-V assay and assay for mitochondrial membrane potential suggested that formononetin suppressed cells proliferation by inducing apoptosis. We detected the expression of apoptosis-related proteins in ovarian cancer cells after treatment with formononetin and found the expression of caspase 3/9 proteins and the ratio of Bax/Bcl-2 were increased in a dose-dependent manner. In addition, wound healing and transwell chamber assays showed that formononetin suppressed the migration and invasion of ovarian cancer cells. And formononetin decreased expression of MMP-2/9 proteins and phosphorylation level of ERK.

CONCLUSIONS

The present results demonstrated that formononetin have potential effects on induction of apoptosis and suppression of migration and invasion.

ESR1 methylation in primary tumors and paired circulating tumor DNA of patients with high-grade serous ovarian cancer

OBJECTIVE

Estrogen receptor, coded by the ESR1 gene, is highly expressed in epithelial ovarian cancer. ESR1 gene is frequently methylated in many types of gynecological malignancies. However, only a few studies attempted to investigate the role of ESR1 methylation and its clinical significance in ovarian cancer so far. The aim of our study was to examine ESR1 methylation status in primary tumors and corresponding circulating tumor DNA of patients with high-grade serous ovarian cancer (HGSC).

METHODS

ESR1 methylation was detected by a highly specific and sensitive real-time methylation-specific PCR assay. Two groups of HGSC samples were analyzed: group A (n = 66 primary tumors) and group B (n = 53 primary tumors and 50 corresponding plasma samples).

RESULTS

ESR1 was found methylated in both groups of primary tumors: in 32/66 (48.5%) of group A and in 15/53 (28.3%) of group B. 19/50 (38.0%) corresponding plasma samples of group B were also methylated for ESR1. A significant agreement for ESR1 methylation was observed between primary tumors and paired plasma ctDNA samples (P = 0.004). Interestingly, the presence of ESR1 methylation in primary tumor samples of group B was significantly correlated with a better overall survival (P = 0.027) and progression-free survival (P = 0.041).

CONCLUSIONS

We report for the first time the presence of ESR1 methylation in plasma ctDNA of patients with HGSC. The agreement between ESR1 methylation in primary tumors and paired ctDNA is statistically significant. Our results indicate a correlation between the presence of ESR1 methylation and a better clinical outcome in HGSC patients.

LncRNA GAS5 suppresses ovarian cancer by inducing inflammasome formation

OBJECTIVE

Long non-coding RNA growth arrest-specific transcript 5 (lncRNA GAS5) is involved in various kinds of cancer. However, the role of lncGAS5 in the development of ovarian cancer remains unclear. In the current study, we explored the cellular mechanism and clinical value of lncRNA GAS5 in ovarian cancer.

METHODS

Quantitative real-time PCR was used to detect mRNA level of LncRNA GAS5 in 20 ovarian cancer tissues. The effect of lncRNA GAS5 on cell proliferation was performed using CCK-8 assay. Cell apoptosis was evaluated by flow cytometry. Western blotting was used to detect the protein level of lncRNA GAS5 potential target. Standard sandwich ELISA was used to quantify the level of inflammatory cytokines. The cells with stable expression of lncRNA GAS5 were injected into nude mice to study the effect of lncRNA GAS5 on tumorigenesis in vivo. Results: The expression of lncRNA GAS5 was significantly decreased in ovarian cancer tissues. Decrease in lncRNA GAS5 expression resulted in increased cell proliferation and colony formation and reduced ovarian cancer cell apoptosis. In contrast, exogenous overexpression of lncRNA GAS5 in ovarian cancer cells inhibited proliferation, colony formation and apoptosis in ovarian cancer cells. In addition, the role of lncRNA GAS5 in ovarian cancer was associated with inflammasome formation and pyroptosis.

CONCLUSION

These results suggested that lncRNA GAS5 acts as tumor suppressor and could be used as a potential treatment target for diagnosis and therapy of ovarian cancer.

Beyond the Biomarker: Understanding the Diverse Roles of Human Epididymis Protein 4 in the Pathogenesis of Epithelial Ovarian Cancer

Human epididymis protein 4 (HE4) is an important clinical biomarker used for the detection of epithelial ovarian cancer (EOC). While much is known about the predictive power of HE4 clinically, less has been reported regarding its molecular role in the progression of EOC. A deeper understanding of HE4’s mechanistic functions may help contribute to the development of novel targeted therapies. Thus far, it has been difficult to recommend HE4 as a therapeutic target owing to the fact that its role in the progression of EOC has not been extensively evaluated. This review summarizes what is collectively known about HE4 signaling and how it functions to promote tumorigenesis, chemoresistance, and metastasis in EOC, with the goal of providing valuable insights that will have the potential to aide in the development of new HE4-targeted therapies.

Bisphenol A and its derivatives decrease expression of chemerin, which reverses its stimulatory action in ovarian cancer cells

Chemerin is an adipocyte-secreted protein that associates with obesity, inflammation, metabolic dysfunction, and carcinogenesis. Previous studies have shown human granulosa cells to produce bioactive chemerin and its receptor CMKLR1. In the present study, we demonstrated that the mRNA level of chemerin receptor is higher in a granulosa cell tumor cell line than in epithelial cancer cells, whereas chemerin expression and secretion were lower. Various exogenous factors, such as bisphenol A and its halogenated derivatives tetrabromobisphenol A and tetrachlorobisphenol A, can affect adipokine expression. For this reason, we investigated the effects of bisphenol A and its derivatives on the expression of chemerin and its receptor. At low nanomolar concentrations, BPA, TBBPA, and TCBPA decreased chemerin expression and secretion only in granulosa cell tumor COV434 cells by both peroxisome proliferator-activated receptor γ and estrogen receptor signaling pathways. Chemerin treatment had no effect on proliferation of ovarian non-cancer and cancer cell lines. However, we also found evidence to support the inhibition of BPA- and TBBPA-induced cell proliferation by chemerin. Taken together, our results indicate for the first time that BPA and its derivatives down-regulate chemerin expression, which can suppress the ability of BPA to induce proliferation. Moreover, both PPARγ and ERs were involved in the BPA-induced decrease in chemerin expression, and its ratio was crucial to exert these effects.

A role for G-protein coupled estrogen receptor (GPER) in estrogen-induced carcinogenesis: Dysregulated glandular homeostasis, survival and metastasis

Mechanisms of carcinogenesis by estrogen center on its mitogenic and genotoxic potential on tumor target cells. These models suggest that estrogen receptor (ER) signaling promotes expansion of the transformed population and that subsequent accumulation of somatic mutations that drive cancer progression occur via metabolic activation of cathecol estrogens or by epigenetic mechanisms. Recent findings that GPER is linked to obesity, vascular pathology and immunosuppression, key events in the development of metabolic syndrome and intra-tissular estrogen synthesis, provides an alternate view of estrogen-induced carcinogenesis. Consistent with this concept, GPER is directly associated with clinicopathological indices that predict cancer progression and poor survival in breast and gynecological cancers. Moreover, GPER manifests cell biological responses and a microenvironment conducive for tumor development and cancer progression, regulating cellular responses associated with glandular homeostasis and survival, invading surrounding tissue and attracting a vascular supply. Thus, the cellular actions attributed to GPER fit well with the known molecular mechanisms of G-protein coupled receptors, GPCRs, namely, their ability to transactivate integrins and EGF receptors and alter the interaction between glandular epithelia and their extracellular environment, affecting epithelial-to-mesenchymal transition (EMT) and allowing for tumor cell survival and dissemination. This perspective reviews the molecular and cellular responses manifested by GPER and evaluates its contribution to female reproductive cancers as diseases that progress as a result of dysregulated glandular homeostasis resulting in chronic inflammation and metastasis. This review is organized in sections as follows: I) a brief synopsis of the current state of knowledge regarding estrogen-induced carcinogenesis, II) a review of evidence from clinical and animal-based studies that support a role for GPER in cancer progression, and III) a mechanistic framework describing how GPER-mediated estrogen action may influence the tumor and its microenvironment.

The positivity of estrogen receptor and progesterone receptor may not be associated with metastasis and recurrence in epithelial ovarian cancer

The estrogen (ER) or progesterone receptors (PR) is positively associated with better clinical outcomes in ovarian cancer. Whether metastasis or recurrence of ovarian cancer is correlated with this association has not been investigated. Data on 894 women with epithelial ovarian cancer were collected and the association between ER or PR positivity and peritoneal or lymph node metastases or recurrence was analysed. ER or PR positivity was higher in high-grade, low-grade serous and endometrioid carcinoma, but lower in mucinous and clear-cell carcinoma. Significantly higher ER or PR positivity was seen in endometrioid carcinoma or high-grade serous carcinoma with peritoneal metastases, respectively, but not other subtypes. In addition, there was no significant difference in ER or PR positivity between cases with and without lymph node metastasis in these five subtypes. In recurrent high-grade serous carcinoma with peritoneal metastases (n = 103), the positivity of ER or PR was 86% and 55% respectively. Our data demonstrate that the association between ER or PR positivity and peritoneal metastases was only seen in endometrioid or high grade serous carcinoma, respectively. There was no association of ER or PR positivity and lymph node metastases. The majority of recurrent high-grade serous carcinoma with peritoneal metastases (86%) were ER positive.

Involvement of AF1q/MLLT11 in the progression of ovarian cancer

The functional role of AF1q/MLLT11, an oncogenic factor involved in a translocation t(1;11)(q21;q23) responsible for acute myeloid leukaemia, has been investigated in hematological and solid malignancies and its expression was found to be linked to tumor progression and poor clinical outcome. In addition to its oncogenic function, AF1q has been shown to play a role in the onset of basal and drug-induced apoptosis in cancer cells of different histotypes, including ovarian cancer. Through in vitro, ex vivo, and in silico approaches, we demonstrated here that AF1q is also endowed with protumorigenic potential in ovarian cancer. In ovarian cancer cell lines, stable AF1q overexpression caused activation of epithelial-to-mesenchymal transition and increased motility/migratory/invasive abilities accompanied by gene expression changes mainly related to Wnt signaling and to signaling pathways involving in ERK/p38 activation. The potential role of AF1q in ovarian cancer progression was confirmed by immunohistochemical and in silico analyses performed in ovarian tumor specimens which revealed that the protein was absent in normal ovarian epithelium and became detectable when atypical proliferation was present. Moreover, AF1q was significantly lower in borderline ovarian tumors (i.e., tumors of low malignant potential without stromal invasion) than in invasive tumors, thus corroborating the association between high AF1q expression and increased migratory/invasive cell behavior and confirming its potential role in ovarian cancer progression. Our findings demonstrated, for the first time, that AF1q is endowed with protumorigenic activity in ovarian cancer, thus highlighting a dual behavior (i.e., protumorigenic and proapoptotic functions) of the protein in the malignancy.

Antitumor activity of a newly developed monoclonal antibody against ROR1 in ovarian cancer cells

Receptor-tyrosine-kinase-like Orphan Receptor 1 (ROR1) is a tyrosine-protein kinase transmembrane receptor and ROR1 overexpression is associated with a poor prognosis in various cancers, including ovarian cancer. Targeting of ROR1 has been evaluated as a novel cancer therapy strategy. This study developed a novel chimeric anti-ROR1 Fab antibody (named ROR1-cFab) and then assessed the antitumor activity of this antibody in ovarian cancer cells, an in vitro model of preclinical cancer therapy. A ROR1-cFab prokaryotic expression vector was constructed from positive fusion cells (splenocytes from mice with high ROR1 immune titers were fused with myeloma cells) after three rounds of sub-clone affinity screening. Then, a variety of assays were employed to assess the binding selectivity and specificity of ROR1-cFab to ROR1 protein. Furthermore, CCK8, flow cytometric apoptosis, wound healing, and Transwell migration assays were used to assess antitumor activity of this newly developed anti-ROR1 antibody in ovarian cancer cells. We demonstrated that ROR1-cFab could specifically bind to ROR1 protein and ROR1-positive ovarian cancer A2780 cells. Functional assays revealed that ROR1-cFab inhibited tumor cell proliferation and migration, as well as inducing apoptosis of ROR1-positive A2780 cells in a dose dependent manner. These effects were not observed in ROR1-negative lose386 cells. In conclusion, ROR1-cFab is a novel anti-ROR1 antibody with a high affinity to ROR1 protein and inhibitory effects on ROR1-positive cells. Future studies will determine whether the ROR1-cFab might be a promising candidate for treatment of ROR1-positive ovarian cancer.

Cells of origin of ovarian cancer: ovarian surface epithelium or fallopian tube?

OBJECTIVE

Ovarian cancer is the fifth most common cancer in women and one of the leading causes of death from gynecological malignancies. Despite of its clinical importance, ovarian tumorigenesis is poorly understood and prognosis remains poor. This is particularly true for the most common type of ovarian cancer, high-grade serous ovarian cancer.

RESULTS

Two models are considered, whether it arises from the ovarian surface epithelium or from the fallopian tube. The first model is based on (1) the pro-inflammatory environment caused by ovulation events, (2) the expression pattern of ovarian inclusion cysts, and (3) biomarkers that are shared by the ovarian surface epithelium and malignant growth. The model suggesting a non-ovarian origin is based on (1) tubal precursor lesions, (2) genetic evidence of BRCA1/2 mutation carriers, and (3) recent animal studies. Neither model has clearly demonstrated superiority over the other. Therefore, one can speculate that high-grade serous ovarian cancer may arise from two different sites that undergo similar changes. Both tissues are derived from the same embryologic origin, which may explain how progenitor cells from different sites can respond similar to stimuli within the ovaries. However, distinct molecular drivers, such as BRCA deficiency, may still preferentially arise from one site of origin as precancerous mutations are frequently seen in the fallopian tube.

CONCLUSIONS

Confirming the origin of ovarian cancer has important clinical implications when deciding on cancer risk-reducing prophylactic surgery. It will be important to identify key biomarker to uncover the sequence of ovarian tumorigenesis.

Iron overload and altered iron metabolism in ovarian cancer

Iron is an essential element required for many processes within the cell. Dysregulation in iron homeostasis due to iron overload is detrimental. This nutrient is postulated to contribute to the initiation of cancer; however, the mechanisms by which this occurs remain unclear. Defining how iron promotes the development of ovarian cancers from precursor lesions is essential for developing novel therapeutic strategies. In this review, we discuss (1) how iron overload conditions may initiate ovarian cancer development, (2) dysregulated iron metabolism in cancers, (3) the interplay between bacteria, iron, and cancer, and (4) chemotherapeutic strategies targeting iron metabolism in cancer patients.

Epithelial-to-Mesenchymal Transition in the Female Reproductive Tract: From Normal Functioning to Disease Pathology

Epithelial-to-mesenchymal transition (EMT) is a physiological process that is vital throughout the human lifespan. In addition to contributing to the development of various tissues within the growing embryo, EMT is also responsible for wound healing and tissue regeneration later in adulthood. In this review, we highlight the importance of EMT in the development and normal functioning of the female reproductive organs (the ovaries and the uterus) and describe how dysregulation of EMT can lead to pathological conditions, such as endometriosis, adenomyosis, and carcinogenesis. We also summarize the current literature relating to EMT in the context of ovarian and endometrial carcinomas, with a particular focus on how molecular mechanisms and the tumor microenvironment can govern cancer cell plasticity, therapy resistance, and metastasis.

Effects of Endocrine-Disrupting Chemicals and Epigenetic Modifications in Ovarian Cancer: A Review

Ovarian cancer (OC) is a relatively fatal female reproductive malignancy. Since the underlying causes are uncertain, it brings us to believe that both genetic and external factors contribute toward development of this lethal disorder. Exposure to endocrine-disrupting chemicals (EDCs) in the form of occupational usage of pesticides, fungicides, herbicides, plasticizers, cosmetics, and so on is potentially carcinogenic and their ability to cause epigenetic modifications has led us to hypothesize that they may play a catalytic role in OC progression. In response to synthetic chemicals, animal models have demonstrated disturbances in the development of ovaries and steroid hormonal levels but in humans, more research is required. The present review is an attempt to address the impact of EDCs on the hormonal system and gene methylation levels that may lead to malfunctioning of the ovaries which may consequently develop in the form of cancer. It can be concluded that endocrine disruptors do have a potential carcinogenicity and their high proportions in human body may cause epigenetic modifications, prompting ovarian surface epithelium to grow in an abnormal manner.

Clinical significance of the estrogen-modifying enzymes steroid sulfatase and estrogen sulfotransferase in epithelial ovarian cancer

17β-estradiol (E2) can contribute to the progression of epithelial ovarian cancer (EOC). Although the majority of patients with EOC are postmenopausal woman, when de novo estrogen production in the ovary has ceased, ovarian cancer cells remain exposed to estrogens synthesized locally in the cancer cells from inactive sulfonated steroid hormone precursors-such as estrone sulfate taken up from the circulation via the sulfatase pathway. An abundance of the estrogen-modifying enzymes, including estrogen-activating steroid sulfatase (STS) and estrogen-inactivating estrogen-sulfotransferase (SULT1E1), is important for providing active estrogen to EOC cells. Therefore, the present study determined the levels of SULT1E1, STS and estrogen receptor α (ERα) protein in paraffin-embedded specimens from 206 patients with Federation of Gynecology and Obstetrics stage II–IV EOC treated with debulking surgery and standard platinum-based adjuvant chemotherapy. The levels of STS, SULT1E1 and ERα were assessed by automated quantitative microscopy-based image analysis subsequent to immunohistochemical staining. Significantly higher SULT1E1 levels were observed in better differentiated EOC tumors compared to grade 3 EOC tumors (P=0.001). STS and SULT1E1 levels were positively associated with ERα abundance (P<0.001 and P=0.001, respectively). In advanced stage high-grade serous EOC (HGSOC; n=132), the most frequent and lethal type of ovarian cancer, SULT1E1 expression was significantly associated with a better overall survival rate (hazard ratio 0.66, 95% confidence interval, 0.45–0.94; P=0.005). These results highlight the importance of SULT1E1-mediated estrogen inactivation in EOC, particularly HGSOC. Therefore, targeting the sulfatase pathway is a potential endocrine therapeutic intervention for certain patients with estrogen-responsive EOC.

Multiple direct and indirect mechanisms drive estrogen-induced tumor growth in high grade serous ovarian cancers

The notion that menopausal estrogen replacement therapy increases ovarian cancer risk, but only for the two more common types (i.e. serous and endometrioid), while possibly decreasing risk for clear cell tumors, is strongly suggestive of causality. However, whether estradiol (E2) is tumorigenic or promotes development of occult preexisting disease is unknown. The present study investigated molecular and cellular mechanisms by which E2 modulates the growth of high grade serous ovarian cancer (HGSOC). Results showed that ERα expression was necessary and sufficient to induce the growth of HGSOC cells in in vitro models. Conversely, in vivo experimental studies demonstrated that increasing the levels of circulating estrogens resulted in a significant growth acceleration of ERα-negative HGSOC xenografts, as well. Tumors from E2-treated mice had significantly higher proliferation rate, angiogenesis, and density of tumor-associated macrophage (TAM) compared to ovariectomized females. Accordingly, immunohistochemical analysis of ERα-negative tissue specimens from HGSOC patients showed a significantly greater TAM infiltration in premenopausal compared to postmenopausal women. This study describes novel insights into the impact of E2 on tumor microenvironment, independently of its direct effect on tumor cell growth, thus supporting the idea that multiple direct and indirect mechanisms drive estrogen-induced tumor growth in HGSOC.

Tea, coffee, and caffeinated beverage consumption and risk of epithelial ovarian cancers

BACKGROUND

The risk for epithelial ovarian cancer associated with the consumption of caffeinated beverages (tea, coffee, and soft drinks) and green tea is inconclusive. However, few studies have investigated the type of caffeinated beverage or the type of tea.

OBJECTIVE

We assessed consumption of tea (black/caffeinated tea and green tea separately), coffee, and caffeinated soft drinks, as well as level of consumption, and the risk for epithelial ovarian cancer and its histotypes.

STUDY DESIGN

This study was conducted within a population-based case-control study in Alberta and British Columbia, Canada from 2001 to 2012. After restricting to cases of epithelial invasive cancers and controls aged 40-79 years who completed an interview that included coffee, soft drink, and tea consumption (ascertained starting in 2005 in British Columbia and 2008 in Alberta), there were a total of 524 cases and 1587 controls. Those that did not meet the threshold for beverage consumption (at least once per month for 6 months or more) were classified as non-drinkers. Adult lifetime cumulative consumption (cup-years=cups/day*years) was calculated. Unconditional logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) to describe the association between the relevant drink consumption and risk.

RESULTS

No excess risk was seen for coffee or caffeinated soft drinks. Similarly, any tea consumption was not associated with risk, but when stratified by the type of tea, there was an increase in risk in black tea only drinkers (aOR=1.56; 95% CI:1.07-2.28 for >40 cup-years), but no excess risk for the exclusive green tea drinkers. Similar findings were observed for post-menopausal women. The association for black tea only consumption was mainly seen in the endometrioid histotype (aOR=3.19; 95% CI: 1.32-7.69).

CONCLUSION

Black tea consumption may be associated with an increased risk epithelial ovarian carcinoma. The excess risk is seen only in the endometrioid histotype but not in serous or clear cell. Further studies are required to confirm these findings and identify the constituents in black tea that may increase the risk.

Dysregulation of Aromatase in Breast, Endometrial, and Ovarian Cancers: An Overview of Therapeutic Strategies

Aromatase is the rate-limiting enzyme in the biosynthesis of estrogens, which play crucial roles on a spectrum of developmental and physiological processes. The biological actions of estrogens are classically mediated by binding to two estrogen receptors (ERs), ERα and ERβ. Encoded by the cytochrome P450, family 19, subfamily A, polypeptide 1 (CYP19A1) gene, aromatase is expressed in a wide variety of tissues, as well as benign and malignant tumors, and is regulated in a pathway- and tissue-specific manner. Overexpression of aromatase, leading to elevated systemic levels of estrogen, is unequivocally linked to the pathogenesis and growth of a number malignancies, including breast, endometrium, and ovarian cancers. Aromatase inhibitors (AIs) are routinely used to treat estrogen-dependent breast cancers in postmenopausal women; however, their roles in endometrial and ovarian cancers remain obscure. While AI therapy is effective in hormone sensitive cancers, they diminish estrogen production throughout the body and, thus, generate undesirable side effects. Despite the effectiveness of AI therapy, resistance to endocrine therapy remains a major concern and is the leading cause of cancer death. Considerable advances, toward mitigating these issues, have evolved in conjunction with a number of histone deacetylase (HDAC) inhibitors for countering an assortment of diseases and cancers, including the aforesaid malignancies. HDACs are a family of enzymes that are frequently dysregulated in human tumors. This chapter will discuss the current understanding of aberrant regulation and expression of aromatase in breast, endometrial, and ovarian cancers, and potential therapeutic strategies for prevention and treatment of these life-threatening diseases.

Epigenetic regulation of glycosylation and the impact on chemo-resistance in breast and ovarian cancer

Glycosylation is one of the most fundamental posttranslational modifications in cellular biology and has been shown to be epigenetically regulated. Understanding this process is important as epigenetic therapies such as those using DNA methyltransferase inhibitors are undergoing clinical trials for the treatment of ovarian and breast cancer. Previous work has demonstrated that altered glycosylation patterns are associated with aggressive disease in women presenting with breast and ovarian cancer. Moreover, the tumor microenvironment of hypoxia results in globally altered DNA methylation and is associated with aggressive cancer phenotypes and chemo-resistance, a feature integral to many cancers. There is sparse knowledge on the impact of these therapies on glycosylation. Moreover, little is known about the efficacy of DNA methyltransferase inhibitors in hypoxic tumors. In this review, we interrogate the impact that hypoxia and epigenetic regulation has on cancer cell glycosylation in relation to resultant tumor cell aggressiveness and chemo-resistance.

Leptin stimulates migration and invasion and maintains cancer stem-like properties in ovarian cancer cells: an explanation for poor outcomes in obese women

The evidence linking obesity with ovarian cancer remains controversial. Leptin is expressed at higher levels in obese women and stimulates cell migration in other epithelial cancers. Here, we explored the clinical impact of overweight/obesity on patient prognosis and leptin's effects on the metastatic potential of ovarian cancer cells. We assessed clinical outcomes in 70 ovarian cancer patients (33 healthy weight and 37 overweight) that were validated with an external cohort from The Cancer Genome Atlas (TCGA) database. Progression-free and overall survival rates were significantly decreased in overweight patients. Similarly, a worse overall survival rate was found in TCGA patients expressing higher leptin/OB-Rb levels. We explored serum and ascites leptin levels and OB-Rb expression in our cohort. Serum and ascites leptin levels were higher in overweight patients experiencing worse survival. OB-Rb was more highly expressed in ascites and metastases than in primary tumors. Leptin exposure increased cancer cell migration/invasion through leptin-mediated activation of JAK/STAT3, PI3/AKT and RhoA/ROCK and promoted new lamellipodial, stress-fiber and focal adhesion formation. Leptin also contributed to the maintenance of stemness and the mesenchymal phenotype in ovarian cancer cells. Our findings demonstrate that leptin stimulated ovarian cancer cell migration and invasion, offering a potential explanation for the poor prognosis among obese women.

17β-Estradiol Reverses Leptin-Inducing Ovarian Cancer Cell Migration by the PI3K/Akt Signaling Pathway

Accumulating evidence suggests that leptin is expressed at higher levels in obese women and stimulates cell migration in epithelial cancers. However, the biology of ovarian cancer is different from others, mainly due to the production of estrogens because of the involvement of ovarian tissue, which is the main source of estrogens; as a result, the levels are at least 100- to 1000-fold higher than normal circulating levels. Thus, ovarian cancer tissues are exposed to 17β-estradiol, which promotes ovarian cancer cell migration and may modulate the effect of other hormones. Therefore, this study investigated the effects of 17β-estradiol (1 nmol/L) with leptin (1-40 ng/mL) at physiological levels, on the migration of OVCAR-3 and SKOV-3 ovarian cancer cells, and the expression levels and activity of metalloproteinases (MMPs) 2 and 9. Here, we found that leptin stimulated ovarian cancer cell line migration, which is mediated via the expression and activity of MMP-9 in the OVCAR-3 but not in the SKOV-3 cells. After the administration of 17β-estradiol and leptin, we observed antagonistic effects of 17β-estradiol on leptin-induced OVCAR-3 cell migration and MMP-9 expression and activity. Moreover, the antagonistic effect of 17β-estradiol on leptin-induced cancer cell migration was reversed by pretreatment of the cells with the phosphatidylinositol 3-kinase (PI3K) pathway inhibitor. Taken together, our results, for the first time, show that in ovarian cancer cells ObR⁺/ER⁺, 17β-estradiol has an antagonistic effect on leptin-induced cell migration as well as MMP-9 expression and activity, which is mediated by the PI3K pathway.

A proteomic signature of ovarian cancer tumor fluid identified by highthroughput and verified by targeted proteomics

Tumor fluid samples have emerged as a rich source for the identification of ovarian cancer in the context of proteomics studies. To uncover differences among benign and malignant ovarian samples, we performed a quantitative proteomic study consisting of albumin immunodepletion, isotope labeling with acrylamide and in-depth proteomic profiling by LC-MS/MS in a pool of 10 samples of each histological type. 1135 proteins were identified, corresponding to 505 gene products. 223 proteins presented associated quantification and the comparative analysis of histological types revealed 75 differentially abundant proteins. Based on this, we developed a panel for targeted proteomic analysis using the multiple reaction monitoring (MRM) method for validation of 51 proteins in individual samples of high-grade serous ovarian tumor fluids (malignant) and benign serous cystadenoma tumor fluids. This analysis showed concordant results in terms of average amounts of proteins, and APOE, SERPINF2, SERPING1, ADAM17, CD44 and OVGP1 were statistically significant between benign and malignant group. The results observed in the MRM for APOE were confirmed by western blotting, where APOE was more abundant in malignant samples. This molecular signature can contribute to improve tumor stratification and shall be investigated in combination with current biomarkers in larger cohorts to improve ovarian cancer diagnosis.

BIOLOGICAL SIGNIFICANCE

Despite advances in cancer research, ovarian cancer has a high mortality and remains a major challenge due to a number of particularities of the disease, especially late diagnosis caused by vague clinical symptoms, the cellular and molecular heterogeneity of tumors, and the lack of effective treatment. Thus, efforts are directed to better understand this neoplasia, its origin, development and, particularly the identification and validation of biomarkers for early detection of the disease in asymptomatic stage. In the present work, we confirmed by MRM method in individual ovarian tumor fluid samples the regulation of 27 proteins out of 33 identified in a highthroughput study. We speculate that the presence and/or differential abundance observed in tumor fluid is a cooperation primarily of high rates of secretion of such tumor proteins to extra tumor environment that will at the end accumulate in plasma, and also the accumulation of acute-phase proteins throughout the entire body. On top of that, consideration of physiological influences in the interpretation of expression observed, including age, menopause status, route-of-elimination kinetics and metabolism of the tumor marker, coexisting disease, hormonal imbalances, life-style influences (smoking, alcoholism, obesity), among others, are mandatory to enable the selection of good protein tumor marker candidates for extensive validation.

Hormone Receptors in Serous Ovarian Carcinoma: Prognosis, Pathogenesis, and Treatment Considerations

A few breakthroughs have been accomplished for the treatment of ovarian cancer, the most deadly gynecologic carcinoma, in the current era of targeted oncologic treatment. The estrogen receptor was the first target of such treatments with the introduction of tamoxifen four decades ago in breast cancer therapeutics. Attempts to duplicate the success of hormonal therapies in ovarian cancer met with mixed results, which may be due to an inferior degree of hormone dependency in this cancer. Alternatively, this may be due to the failure to clearly identify the subsets of ovarian cancer with hormone sensitivity. This article reviews the expression of hormone receptors by ovarian cancer cells, the prognostic value of these expressions, and their predictive capacity for response to hormonal agents. The possible ways ahead are briefly discussed.

Ellagic Acid and Resveratrol Prevent the Development of Cisplatin Resistance in the Epithelial Ovarian Cancer Cell Line A2780

Purpose. Several studies have shown that natural compounds like resveratrol or ellagic acid have anticancer and antioxidant properties and can stimulate apoptosis in many cancer cell lines. The aim of this study was to elucidate if resveratrol or ellagic acid, respectively, could improve the efficacy of cisplatin in ovarian cancer. Methods. As a cellular resistance model, the epithelial ovarian cancer cell line A2780 and its cisplatin-resistant subclone A2780CisR were used. A2780CisR was obtained by intermittent treatment of A2780 with cisplatin for 26 weekly cycles and showed a 4-6-fold increased resistance towards cisplatin compared to A2780. Results. Pretreatment with resveratrol or ellagic acid 48 h prior to treatment with cisplatin showed a moderate enhancement of cisplatin cytotoxicity in A2780CisR cells (shift factors were 1.6 for ellagic acid and 2.5 for resveratrol). However, intermittent treatment of A2780 with cisplatin for 26 weekly cycles in permanent presence of resveratrol or ellagic acid, respectively, completely prevented the development of cisplatin resistance. The generated cell lines named A2780Resv and A2780Ellag displayed functional characteristics (migration, proliferation, apoptosis, activation of ErbB3, ROS generation) similar to the parental cell line A2780. Conclusion. In conclusion, weekly intermittent treatment cycles of cisplatin-sensitive ovarian cancer cells with cisplatin retain cisplatin chemosensitivity in permanent presence of ellagic acid or resveratrol, respectively, whereas clinically relevant cisplatin chemoresistance develops in the absence of ellagic acid or resveratrol. Use of natural phenolic compounds may thus be a promising approach to prevent cisplatin resistance in ovarian cancer.

Wilms tumor protein 1 (WT1)-- not only a diagnostic but also a prognostic marker in high-grade serous ovarian carcinoma

AIMS

Wilms tumor protein 1 (WT1) expression is used in gynecological pathology as a diagnostic marker of serous differentiation, and is frequently co-expressed with ER-α. Early phase studies on WT1 vaccine in gynecological cancers are ongoing. In this study we aimed to determine the prognostic value of WT1 in high-grade serous ovarian carcinoma.

METHODS

WT1 protein expression was determined by immunohistochemistry in a cohort of 207 primary high-grade serous ovarian carcinomas. WT1 mRNA expression was evaluated in a cohort of 1137 ovarian carcinomas from publically available gene expression datasets.

RESULTS

High WT1 expression was a significant positive prognostic factor in primary high-grade serous ovarian carcinoma regarding overall survival (OS, p=0.008) and progression free survival (PFS, p=0.015), which was independent of age, stage, and residual tumor (OS: p=0.024, PFS: p=0.047). The prognostic significance of immunohistochemical WT1 expression could be reproduced in an independent cohort of 72 patients. On the mRNA level the prognostic significance was validated in silico in publically available gene expression datasets including TCGA data (OS: p=0.002, PFS: p=0.011). WT1 expression was significantly linked to ER-α expression (p=0.001), and tumors that co-expressed both markers (WT1+/ER-α+) had a longer survival time than tumors of all other marker combinations (OS: p=0.002, PFS: p=0.013).

CONCLUSION

We present WT1 as a robust prognostic marker in high-grade serous ovarian carcinoma, which adds prognostic information to ER-α. This should be kept in mind when WT1 is used as a biomarker in the context of WT1-targeting therapies.

Treating gynecologic malignancies with selective estrogen receptor downregulators (SERDs): promise and challenges

Endometrial and ovarian cancers are estrogen-dependent gynecologic malignancies. Although many are estrogen receptor (ER) positive, treatment with the selective estrogen receptor modulator (SERM) tamoxifen, a tissue selective partial-agonist, has demonstrated only modest clinical benefit. Selective estrogen receptor downregulators (SERDs) are pure ER antagonists showing a benefit for advanced ER positive breast cancer, which has bolstered their potential use for ER positive gynecologic malignancies. We summarize these preclinical and clinical data, suggesting that a subpopulation of patients with endometrial or ovarian cancer exists in which treatment with SERDs results in improved outcome. However, the full potential of SERDs for a gynecologic malignancies will be realized only when the appropriate predictive biomarkers are identified. Additionally, a further understanding ER signaling in the context of ovarian and endometrial tissues that appear to involve c-Src and other kinase pathways is needed to successfully address the emergence of resistance with rationally designed combination therapies.

Transcript level of AKR1C3 is down-regulated in gastric cancer

Steroid hormones have been shown to play a role in gastric carcinogenesis. Large amounts of steroid hormones are locally produced in the peripheral tissues of both genders. Type 5 of 17β-hydroxysteroid dehydrogenase, encoded by the AKR1C3 gene, plays a pivotal role in both androgen and estrogen metabolism, and its expression was found to be deregulated in different cancers. In this study we measured AKR1C3 transcript and protein levels in nontumoral and primary tumoral gastric tissues, and evaluated their association with some clinicopathological features of gastric cancer (GC). We found decreased levels of AKR1C3 transcript (p < 0.0001) and protein (p = 0.0021) in GC tissues compared with the adjacent, apparently histopathologically normal, mucosa. Lower levels of AKR1C3 transcript were observed in diffuse and intestinal types of GC, whereas AKR1C3 protein levels were decreased in tumors with multisite localization, in diffuse histological type, T3, T4, and G3 grades. We also determined the effect of the histone deacetylase inhibitor sodium butyrate (NaBu) on AKR1C3 expression in EPG 85-257 and HGC-27 GC cell lines. We found that NaBu elevates the levels of both AKR1C3 transcript and protein in the cell lines we investigated. Together, our results suggest that decreased expression of AKR1C3 may be involved in development of GC and can be restored by NaBu.

Estrogen Secreted by Mesenchymal Stem Cells Necessarily Determines Their Feasibility of Therapeutical Application

Mesenchymal stem cells are therapeutically applicable and involved in the development of some types of diseases including estrogen (E2)-related ones. Little is known about E2 secretion by mesenchymal stem cells and its potential influence on their therapeutical applications. Our in vitro experiments showed that BMSCs cultured from C57BL/6J mice secreted E2 in a time-dependent manner. In vivo study identified a significantly increased E2 level in serum after a single administration of BMSCs, and a sustained elevation of E2 level upon a repetitive administration. Morris water maze test in the ovariectomised (OVX) mouse model revealed BMSCs transplantation ameliorated OVX-induced memory deficits by secreted E2. On the contrary, in endometriosis model, BMSCs transplantation aggravated endometriotic lesions because of E2 secretion. Mechanistically, the aromatase cytochrome P450 appeared to be critical for the biosynthesis and exerted effects of estrogen secretion by BMSCs. Our findings suggested that BMSCs transplantation is on the one hand an attractive option for the therapeutic treatment of diseases associated with E2 deficits in part through E2 secretion, on the other hand a detrimental factor for the E2-exasperated diseases largely via E2 production. It is important and necessary to monitor serum E2 level before and after the initiation of BMSCs therapy.