Differential expression of progesterone receptor isoforms A and B in the normal ovary, and in benign, borderline, and malignant ovarian tumors

Reevaluating the Role of Progesterone in Ovarian Cancer: Is Progesterone Always Protective?

Ovarian cancer (OC) represents a collection of rare but lethal gynecologic cancers where the difficulty of early detection due to an often-subtle range of abdominal symptoms contributes to high fatality rates. With the exception of BRCA1/2 mutation carriers, OC most often manifests as a post-menopausal disease, a time in which the ovaries regress and circulating reproductive hormones diminish. Progesterone is thought to be a "protective" hormone that counters the proliferative actions of estrogen, as can be observed in the uterus or breast. Like other steroid hormone receptor family members, the transcriptional activity of the nuclear progesterone receptor (nPR) may be ligand dependent or independent and is fully integrated with other ubiquitous cell signaling pathways often altered in cancers. Emerging evidence in OC models challenges the singular protective role of progesterone/nPR. Herein, we integrate the historical perspective of progesterone on OC development and progression with exciting new research findings and critical interpretations to help paint a broader picture of the role of progesterone and nPR signaling in OC. We hope to alleviate some of the controversy around the role of progesterone and give insight into the importance of nPR actions in disease progression. A new perspective on the role of progesterone and nPR signaling integration will raise awareness to the complexity of nPRs and nPR-driven gene regulation in OC, help to reveal novel biomarkers, and lend critical knowledge for the development of better therapeutic strategies.

Hormone Receptors and Epithelial Ovarian Cancer: Recent Advances in Biology and Treatment Options

Epithelial ovarian cancer (EOC) is a significant cause of cancer-related mortality in women. Despite advances in diagnosis and treatment, EOC remains a challenging disease to manage, and the 5-year survival rate is still poor. The role of hormone receptors (HRs) in EOC carcinogenesis and prognosis has been actively explored; however, the role of hormone therapy (HT) in the treatment of these tumors is not well established. Most available data on HT mainly come from retrospective series and small early clinical trials. Several of these studies suggest that HT may have a role in adjuvant, maintenance therapy, or in the case of recurrent disease, especially for some subtypes of EOC (e.g., low-grade serous EOC). Furthermore, HT has recently been combined with targeted therapies, but most studies evaluating these combinations are still ongoing. The main aim of this review is to provide an overview of the progress made in the last decade to characterize the biological and prognostic role of HRs for EOC and the developments in their therapeutic targeting through HT.

Effects of the Overexpression of Progesterone Receptors on a Precancer p53 and Rb-Defective Human Fallopian Tube Epithelial Cell Line

This study investigated the effects of progesterone receptors A (PRA) and B (PRB) on proliferation, migration, invasion, anchorage-independent growth (AIG), and apoptosis of FE25 cells, a precancer p53- and retinoblastoma-defective human fallopian tube epithelial cell line. We observed that the transfection of PRA (FE25-PRA) or PRB (FE25-PRB) into FE25 cells significantly increased the expression of PRA or PRB at both RNA and protein levels without affecting cell morphology. The FE25-PRA cells exhibited slower proliferation, whereas FE25-PRB showed faster cell proliferation than the control cells. In contrast, the FE25-PRA cells showed the highest migration and invasion abilities, whereas the FE25-PRB cells showed the lowest migration and invasion abilities. After treatment with progesterone, all cell types showed decreased AIG levels, increased apoptotic rates in Terminal deoxynucleotidyl transferase (TdT) dUTP nick end labeling assay (TUNEL) staining, and increased levels of apoptotic proteins ascertained based on cleaved caspase-3 levels. The half-maximal inhibitory concentration of carboplatin increased in FE25-PRB cells, but that of paclitaxel remained unchanged. Overall, this study suggests that PRA and PRB have distinct roles in regulating the behavior of FE25 cells, and targeting these receptors could be a potential therapeutic strategy for ovarian cancer treatment. If PRA or PRB overexpression is observed in high-grade serous carcinoma, progesterone could be considered as an adjuvant therapy for these specific cancer patients. However, further research is needed to confirm these findings and investigate the mechanisms underlying these effects.

Hormone therapy for ovarian cancer: Emphasis on mechanisms and applications (Review)

Ovarian cancer (OC) remains the leading cause of mortality due to gynecological malignancies. Epidemiological studies have demonstrated that steroid hormones released from the hypothalamic-pituitary-ovarian axis can play a role in stimulating or inhibiting OC progression, with gonadotropins, estrogens and androgens promoting OC progression, while gonadotropin-releasing hormone (GnRH) and progesterone may be protective factors in OC. Experimental studies have indicated that hormone receptors are expressed in OC cells and mediate the growth stimulatory or growth inhibitory effects of hormones on these cells. Hormone therapy agents have been evaluated in a number of clinical trials. The majority of these trials were conducted in patients with relapsed or refractory OC with average efficacy and limited side-effects. A better understanding of the mechanisms through which hormones affect cell growth may improve the efficacy of hormone therapy. In the present review article, the role of hormones (GnRH, gonadotropins, androgens, estrogens and progestins) and their receptors in OC tumorigenesis, and hormonal therapy in OC treatment is discussed and summarized.

A Review of Principal Studies on the Development and Treatment of Epithelial Ovarian Cancer in the Laying Hen Gallus gallus

Often referred to as the silent killer, ovarian cancer is the most lethal gynecologic malignancy. This disease rarely shows any physical symptoms until late stages and no known biomarkers are available for early detection. Because ovarian cancer is rarely detected early, the physiology behind the initiation, progression, treatment, and prevention of this disease remains largely unclear. Over the past 2 decades, the laying hen has emerged as a model that naturally develops epithelial ovarian cancer that is both pathologically and histologically similar to that of the human form of the disease. Different molecular signatures found in human ovarian cancer have also been identified in chicken ovarian cancer including increased CA125 and elevated E-cadherin expression, among others. Chemoprevention studies conducted in this model have shown that decreased ovulation and inflammation are associated with decreased incidence of ovarian cancer development. The purpose of this article is to review the major studies performed in laying hen model of ovarian cancer and discuss how these studies shape our current understanding of the pathophysiology, prevention, and treatment of epithelial ovarian cancer.

Progesterone Receptors Promote Quiescence and Ovarian Cancer Cell Phenotypes via DREAM in p53-Mutant Fallopian Tube Models

CONTEXT

The ability of ovarian steroids to modify ovarian cancer (OC) risk remains controversial. Progesterone is considered to be protective; recent studies indicate no effect or enhanced OC risk. Knowledge of progesterone receptor (PR) signaling during altered physiology that typifies OC development is limited.

OBJECTIVE

This study defines PR-driven oncogenic signaling mechanisms in p53-mutant human fallopian tube epithelia (hFTE), a precursor of the most aggressive OC subtype.

METHODS

PR expression in clinical samples of serous tubal intraepithelial carcinoma (STIC) lesions and high-grade serous OC (HGSC) tumors was analyzed. Novel PR-A and PR-B isoform-expressing hFTE models were characterized for gene expression and cell cycle progression, emboli formation, and invasion. PR regulation of the DREAM quiescence complex and DYRK1 kinases was established.

RESULTS

STICs and HGSC express abundant activated phospho-PR. Progestin promoted reversible hFTE cell cycle arrest, spheroid formation, and invasion. RNAseq/biochemical studies revealed potent ligand-independent/-dependent PR actions, progestin-induced regulation of the DREAM quiescence complex, and cell cycle target genes through enhanced complex formation and chromatin recruitment. Disruption of DREAM/DYRK1s by pharmacological inhibition, HPV E6/E7 expression, or DYRK1A/B depletion blocked progestin-induced cell arrest and attenuated PR-driven gene expression and associated OC phenotypes.

CONCLUSION

Activated PRs support quiescence and pro-survival/pro-dissemination cell behaviors that may contribute to early HGSC progression. Our data support an alternative perspective on the tenet that progesterone always confers protection against OC. STICs can reside undetected for decades prior to invasive disease; our studies reveal clinical opportunities to prevent the ultimate development of HGSC by targeting PRs, DREAM, and/or DYRKs.

Carcinogenic effects of bisphenol A in breast and ovarian cancers

Endocrine-disrupting chemicals (EDCs) are exogenous chemical compounds ubiquitously found in everyday life of the modern world. EDCs enter the human body where they act similarly to endogenous hormones, altering the functions of the endocrine system and causing adverse effects on human health. Bisphenol A (BPA), the principal representative of this class, is a carbon-based synthetic plastic, and a key element in manufacturing cans, reusable water bottles and medical equipment. BPA mimics the actions of estrogen on multiple levels by activating estrogen receptors α and β. BPA regulates various processes, such as cell proliferation, migration and apoptosis, leading to neoplastic changes. Considering genetic mechanisms, BPA exerts its functions via multiple oncogenic signaling pathways, including the STAT3, PI3K/AKT and MAPK pathways. Furthermore, BPA is associated with various modifications of the reproductive system in both males and females. These alterations include benign lesions, such as endometrial hyperplasia, the development of ovarian cysts, an increase in the ductal density of mammary gland cells and other preneoplastic lesions. These benign lesions may continue to develop to breast or ovarian cancer; the effects of BPA depend on various molecular and epigenetic mechanisms that dictate whether the endocrine or reproductive system is impacted, wherein preexisting benign lesions can become cancerous. The present review supports the need for continuous research on BPA, considering its widespread use and most available data suggesting a carcinogenic effect of BPA on the female reproductive system. Although most studies on BPA have been conducted in vitro with human cells or in vivo with animal models, it can be argued that more studies should be conducted in vivo with humans to further promote understanding of the impact of BPA.

Progesterone decreases ovarian cancer cells migration and invasion

The progression of cancer depends on the interaction between the cells and their microenvironment. Progesterone is a steroid and progestogen sex hormone produced by the corpus luteum, which is a transitory endocrine gland in female mammals and prepares the endometrium for implantation. Also, progesterone is involved in antitumorigenic process in different types of cancer. Our goal is to investigate the role of progesterone in cell invasion and migration. Ovarian cells were treated with different concentrations of progesterone. 500 nM or 1 μM progesterone decreased the migration of the cells in 24 h or less without affecting the viability. Immunoblot showed that treatment with 1 μM progesterone decreased the phosphorylated forms of Src and FAK, and the cells were less polarized. Our results suggest that progesterone interferes with migration and invasion of ovarian cells. Inhibitory experiments inferred the progesterone receptor playing a role in migration and invasion. Decreased phosphorylation of molecules involved in these processes was also found.

How microplastic components influence the immune system and impact on children health: Focus on cancer

BACKGROUND

As a result of human socioeconomic activity, industrial wastes have increased distressingly. Plastic pollution is globally distributed across the world due to its properties of buoyancy and durability. A big health hazard is the sorption of toxicants to plastic while traveling through the environment. Two broad classes of plastic-related chemicals are of critical concern for human health-bisphenols and phthalates. Bisphenol A (BPA) is an endocrine-disruptor compound (EDC) with estrogenic activity. It is used in the production of materials that are used daily. The endocrine modulating activity of BPA and its effects on reproductive health has been widely studied. BPA also has effects on the immune system; however, they are poorly investigated and the available data are inconclusive. Phthalates are also EDCs used as plasticizers in a wide array of daily-use products. Since these compounds are not covalently bound to the plastic matrix, they easily leach out from it, leading to high human exposure. These compounds exert several cell effects through modulating different endocrine pathways, such as estrogen, androgen, peroxisome proliferator-activated receptor gamma, and arylhydrocarbon receptor pathways. The exposure to both classes of plastic derivatives during critical periods has detrimental effects on human health.

METHODS

In this review, we have compiled the most important of their perinatal effects on the function of the immune system and their relationship to the development of different types of cancer.

RESULTS/CONCLUSION

The administration of bisphenols and phthalates during critical stages of development affects important immune system components, and the immune function; which might be related to the development of different diseases including cancer.

Correlation of NRF2 and progesterone receptor and its effects on ovarian cancer biology

Purpose

This study aimed to investigate the potential prognostic impact of nuclear factor erythroid 2-related factor 2 (NRF2) and progesterone receptor A (PRA)/progesterone receptor B (PRB) in ovarian cancer patients which might be the rationale for putative new treatment strategies.

Patients and methods

The presence of NRF2 and PRA/PRB was investigated in 156 ovarian cancer samples using immunohistochemistry (IHC). Staining of NRF2 and PRA/PRB was rated using the semi-quantitative immunoreactive score (IR score, Remmele’s score) and correlated to clinical and pathological data. NRF2 and PRA/PRB expression were compared with respect to the overall survival (OS).

Results

NRF2 staining was different in both, the cytoplasm and nucleus between the histological subtypes (p=0.001 and p=0.02, respectively). There was a significant difference in the PRA expression comparing all histological subtypes (p=0.02). Histological subtypes showed no significant differences in the PRB expression. A strong correlation of cytoplasmic NRF2 and PRA expression was detected (cc=0.247, p=0.003) as well as of cytoplasmic NRF2 and PRB expression (cc=0.25, p=0.003), confirmed by immunofluorescence double staining. Cytoplasmic NRF2 expression was associated with a longer OS (median 50.6 vs 32.5 months; p=0.1) as it was seen for PRA expression (median 63.4 vs 33.1 months; p=0.08), although not statistically significant. In addition, high PRB expression (median 80.4 vs 32.5 months; p=0.04) and concurrent expression of cytoplasmic NRF2 and PRA were associated with a significantly longer OS (median 109.7 vs 30.6 months; p=0.02). The same relationship was also noted for NRF2 and PRB with improved OS for patients expressing both cytoplasmic NRF2 and PRB (median 153.5 vs 30.6 months; p=0.009). Silencing of NFE2L2 induced higher mRNA expression of PGR in the cancer cell line OVCAR3 (p>0.05) confirming genetic interactions of NRF2 and PR.

Conclusion

In this study, the combination of cytoplasmic NRF2 and high PRA/PRB expression was demonstrated to be associated with improved overall survival in ovarian cancer patients. Further understanding of interactions within the NRF2/AKR1C1/PR pathway could open new additional therapeutic approaches.

Progesterone acts via the progesterone receptor to induce adamts proteases in ovarian cancer cells

BACKGROUND

Ovarian carcinomas, usually associated with sex hormones dysregulation, are the leading cause of gynecological neoplastic death. In normal ovaries, hormones play a central role in regulating cell proliferation, differentiation, and apoptosis. On the other hand, hormonal alterations also play a variety of roles in cancer. Stimulation by sex hormones potentially affects gene expression, invasiveness, cell growth and angiogenesis. Proteases of the "a disintegrin and metalloproteinase with thrombospondin motifs" (ADAMTS) family are secreted by different cell types and become involved in collagen processing, cleavage of the proteoglycan matrix, and angiogenesis. We evaluated whether sex hormones affect ADAMTS 1 and 4 expression in ovarian cancer cells.

METHODS

We analysed mRNA and protein levels in human ovarian tumor cells with different degrees of malignancy, NIH-OVCAR-3 and ES-2, that were treated or not with estrogen, testosterone and progesterone.

RESULTS

Our results suggest that progesterone increases ADAMTS protein and mRNA levels in the lysates from ES-2 cells, and it increases ADAMTS protein in the lysates and conditioned media from NIH-OVCAR-3. Progesterone effects were reversed by RU486 treatment.

CONCLUSION

We conclude that progesterone acts via the progesterone receptor to modulate ADAMTS 1 and 4 levels in ovarian cancer cell lines.

Active FOXO1 Is a Key Determinant of Isoform-Specific Progesterone Receptor Transactivation and Senescence Programming

Progesterone promotes differentiation coupled to proliferation and prosurvival in the breast, but inhibits estrogen-driven growth in the reproductive tract and ovaries. Herein, it is demonstrated, using progesterone receptor (PR) isoform-specific ovarian cancer model systems, that PR-A and PR-B promote distinct gene expression profiles that differ from PR-driven genes in breast cancer cells. In ovarian cancer models, PR-A primarily regulates genes independently of progestin, while PR-B is the dominant ligand-dependent isoform. Notably, FOXO1 and the PR/FOXO1 target gene p21 (CDKN1A) are repressed by PR-A, but induced by PR-B. In the presence of progestin, PR-B, but not PR-A, robustly induced cellular senescence via FOXO1-dependent induction of p21 and p15 (CDKN2B). Chromatin immunoprecipitation (ChIP) assays performed on PR isoform-specific cells demonstrated that while each isoform is recruited to the same PRE-containing region of the p21 promoter in response to progestin, only PR-B elicits active chromatin marks. Overexpression of constitutively active FOXO1 in PR-A-expressing cells conferred robust ligand-dependent upregulation of the PR-B target genes GZMA, IGFBP1, and p21, and induced cellular senescence. In the presence of endogenous active FOXO1, PR-A was phosphorylated on Ser294 and transactivated PR-B at PR-B target genes; these events were blocked by the FOXO1 inhibitor (AS1842856). PR isoform-specific regulation of the FOXO1/p21 axis recapitulated in human primary ovarian tumor explants treated with progestin; loss of progestin sensitivity correlated with high AKT activity.

IMPLICATIONS

This study indicates FOXO1 as a critical component for progesterone signaling to promote cellular senescence and reveals a novel mechanism for transcription factor control of hormone sensitivity.

Sex Steroid Hormone Receptor Expression Affects Ovarian Cancer Survival

BACKGROUND AND AIMS

Although most ovarian cancers express estrogen (ER), progesterone (PR), and androgen (AR) receptors, they are currently not applied in clinical decision making. We explored the prognostic impact of sex steroid hormone receptor protein and mRNA expression on survival in epithelial ovarian cancer.

METHODS

Immunohistochemical stainings for ERα, ERβ, PR, and AR were assessed in relation to survival in 118 serous and endometrioid ovarian cancers. Expression of the genes encoding the four receptors was studied in relation to prognosis in the molecular subtypes of ovarian cancer in an independent data set, hypothesizing that the expression levels and prognostic impact may differ between the subtypes.

RESULTS

Expression of PR or AR protein was associated with improved 5-year progression-free (P=.001 for both) and overall survival (P<.001 for both, log-rank test). ERα and ERβ did not provide prognostic information. Patients whose tumors coexpressed PR and AR had the most favorable prognosis, and this effect was retained in multivariable analyses. Analyses of the corresponding genes using an independent data set revealed differences among the molecular subtypes, but no clear relationship between high coexpression of PGR and AR and prognosis.

CONCLUSIONS

A favorable outcome was seen for patients whose tumors coexpressed PR and AR. Gene expression data suggested variable effects in the different molecular subtypes. These findings demonstrate a prognostic role for PR and AR in ovarian cancer and support that tumors should be stratified based on molecular as well as histological subtypes in future studies investigating the role of endocrine treatment in ovarian cancer.

Progesterone action in breast, uterine, and ovarian cancers

Progesterone and progesterone receptors (PRs) are essential for the development and cyclical regulation of hormone-responsive tissues including the breast and reproductive tract. Altered functions of PR isoforms contribute to the pathogenesis of tumors that arise in these tissues. In the breast, progesterone acts in concert with estrogen to promote proliferative and pro-survival gene programs. In sharp contrast, progesterone inhibits estrogen-driven growth in the uterus and protects the ovary from neoplastic transformation. Progesterone-dependent actions and associated biology in diverse tissues and tumors are mediated by two PR isoforms, PR-A and PR-B. These isoforms are subject to altered transcriptional activity or expression levels, differential crosstalk with growth factor signaling pathways, and distinct post-translational modifications and cofactor-binding partners. Herein, we summarize and discuss the recent literature focused on progesterone and PR isoform-specific actions in breast, uterine, and ovarian cancers. Understanding the complexity of context-dependent PR actions in these tissues is critical to developing new models that will allow us to advance our knowledge base with the goal of revealing novel and efficacious therapeutic regimens for these hormone-responsive diseases.

Bisphenol A and hormone-associated cancers: current progress and perspectives

Bisphenol A (BPA), a carbon-based synthetic compound, exhibits hormone-like properties and is present ubiquitously in the environment and in human tissues due to its widespread use and biological accumulation. BPA can mimic estrogen to interact with estrogen receptors α and β, leading to changes in cell proliferation, apoptosis, or migration and thereby, contributing to cancer development and progression. At the genetic level, BPA has been shown to be involved in multiple oncogenic signaling pathways, such as the STAT3, MAPK, and PI3K/AKT pathways. Moreover, BPA may also interact with other steroid receptors (such as androgen receptor) and plays a role in prostate cancer development. This review summarizes the current literature regarding human exposure to BPA, the endocrine-disrupting effects of BPA, and the role of BPA in hormone-associated cancers of the breast, ovary, and prostate.

Antiprogestins in gynecological diseases

Antiprogestins constitute a group of compounds, developed since the early 1980s, that bind progesterone receptors with different affinities. The first clinical uses for antiprogestins were in reproductive medicine, e.g., menstrual regulation, emergency contraception, and termination of early pregnancies. These initial applications, however, belied the capacity for these compounds to interfere with cell growth. Within the context of gynecological diseases, antiprogestins can block the growth of and kill gynecological-related cancer cells, such as those originating in the breast, ovary, endometrium, and cervix. They can also interrupt the excessive growth of cells giving rise to benign gynecological diseases such as endometriosis and leiomyomata (uterine fibroids). In this article, we present a review of the literature providing support for the antigrowth activity that antiprogestins impose on cells in various gynecological diseases. We also provide a summary of the cellular and molecular mechanisms reported for these compounds that lead to cell growth inhibition and death. The preclinical knowledge gained during the past few years provides robust evidence to encourage the use of antiprogestins in order to alleviate the burden of gynecological diseases, either as monotherapies or as adjuvants of other therapies with the perspective of allowing for long-term treatments with tolerable side effects. The key to the clinical success of antiprogestins in this field probably lies in selecting those patients who will benefit from this therapy. This can be achieved by defining the genetic makeup required - within each particular gynecological disease - for attaining an objective response to antiprogestin-driven growth inhibition therapy.Free Spanish abstractA Spanish translation of this abstract is freely available at http://www.reproduction-online.org/content/149/1/15/suppl/DC1.

Ovarian surface epithelium receptors during pregnancy and estrus cycle of rats with emphasis on steroids and gonadotropin fluctuation

The present study is designed to demonstrate the ovarian surface epithelial cells' (OSE) estrogen receptor α (ERα) and progesterone receptor (PR) during pregnancy and estrous cycle in rat. Moreover, determination of the levels of plasma progesterone, estradiol, FSH and LH was also made. The levels of plasma progesterone, estradiol, FSH and LH concentrations were determined on days 7 (n = 5), 14 (n = 5), and 21 (n = 5) of pregnancy in three groups of rats and during the estrous cycle (n = 5) using an ELISA kit. Immunohistochemical method for PR and ERα expressions was also made on the ovary. During pregnancy, FSH and LH remained low except at term when LH levels began to increase from 16 ng/ml to 47 ng/ml. Progesterone levels significantly exceeded estradiol values in all pregnant rats with a peak value of 202 ng/ml on day 14. Elevated progesterone levels were associated negatively with LH and estradiol levels during pregnancy. The levels of estradiol surged significantly on day 21. Immunohistochemistry of the ovary showed low levels of OSE cells staining positive for ERα expression. ERα positive cells were absent on day 7 and 14 of pregnancy, only day 21 recorded a very low percentage of immunostaining (0.5%) within the nuclei of OSE cells. On the contrary, immunostaining of PR was not observed within the nuclei of OSE cells in all groups of study. In conclusion, these results may suggest that the progesterone effect during pregnancy seems to be overriding the positive effect of estrogens on OSE cells. High progesterone levels may have a direct negative effect on gonadotropin production and thereby it might inhibit events leading to both follicular development and OSE proliferation. Understanding the factors affecting OSE proliferation may help elucidating the mechanism(s) of assisted diseases such as ovarian cancer.

Survival of women with ovarian carcinomas and borderline tumors is not affected by estrogen and progesterone receptor status

Objective

To examine the patterns of estrogen receptor (ER) and progesterone receptor (PR) expression in borderline ovarian tumors (BOTs) and ovarian carcinomas. We also assessed the disease-free survival (DFS) and overall survival (OS) in women with ovarian carcinoma, in relation to ER and/or PR expression.

Methods

We examined ER/PR expression in 38 BOTs and 172 ovarian carcinomas removed from patients treated at the State University of Campinas-UNICAMP (Brazil), from 1993 to 2008 and followed for up to 60 months using tissue microarray-based immunohistochemistry.

Results

Twenty-eight (73.7%) mucinous and 10 (26.3%) serous BOTs were included. Ovarian carcinomas consisted mainly of 79 (46.0%) serous, 44 (25.5%) mucinous, 17 (9.8%) endometrioid, 10 (5.8%) clear-cell types. There was no significant difference of the ER/PR expression between BOT and ovarian carcinoma (p=0.55 for ER alone, 0.90 for PR alone, and 0.12 for combined expression). The level of ER/PR expression in BOTs was significantly higher in serous than in mucinous tumors (p<0.01). In carcinomas, ER/PR was higher in serous tumors than in mucinous (p<0.01) and clear cell tumors (p=0.02), and higher in endometrioid tumors than in mucinous tumors (p<0.01). DFS was affected neither by the clinical characteristics nor by combined steroid receptor status. OS was found to be significantly worse (p<0.01) only in women with stages II-IV tumors and those with residual disease after surgery (p<0.01).

Conclusion

Overall, serous and endometrioid tumors were predominantly ER/PR positive, whereas mucinous and clear-cell tumors were preponderantly ER/PR negative. DFS and OS were not affected by ER/PR expression.

Hormone response in ovarian cancer: time to reconsider as a clinical target?

Ovarian cancer is the sixth most common cancer worldwide among women in developed countries and the most lethal of all gynecologic malignancies. There is a critical need for the introduction of targeted therapies to improve outcome. Epidemiological evidence suggests a critical role for steroid hormones in ovarian tumorigenesis. There is also increasing evidence from in vitro studies that estrogen, progestin, and androgen regulate proliferation and invasion of epithelial ovarian cancer cells. Limited clinical trials have shown modest response rates; however, they have consistently identified a small subset of patients that respond very well to endocrine therapy with few side effects. We propose that it is timely to perform additional well-designed trials that should include biomarkers of response.

Hormone response in ovarian cancer: time to reconsider as a clinical target?

Ovarian cancer is the sixth most common cancer worldwide among women in developed countries and the most lethal of all gynecologic malignancies. There is a critical need for the introduction of targeted therapies to improve outcome. Epidemiological evidence suggests a critical role for steroid hormones in ovarian tumorigenesis. There is also increasing evidence from in vitro studies that estrogen, progestin, and androgen regulate proliferation and invasion of epithelial ovarian cancer cells. Limited clinical trials have shown modest response rates; however, they have consistently identified a small subset of patients that respond very well to endocrine therapy with few side effects. We propose that it is timely to perform additional well-designed trials that should include biomarkers of response.

Expression of membrane progesterone receptors (mPR/PAQR) in ovarian cancer cells: implications for progesterone-induced signaling events

The high mortality rates associated with ovarian cancer are largely due to a lack of highly effective treatment options for advanced stage disease; a time when initial diagnosis most commonly occurs. Recent evidence suggests that the steroid hormone, progesterone, may possess anti-tumorigenic properties. With the discovery of a new class of membrane-bound progesterone receptors (mPRs) belonging to the progestin and adipoQ receptor (PAQR) gene family in the ovary, there are undefined mechanisms by which progesterone may inhibit tumor progression. Therefore, our goal was to define potential mPR-dependent signaling mechanisms operative in ovarian cancer cells. We detected abundant mPRα (PAQR7), mPRβ (PAQR8), and mPRγ (PAQR5), but not classical nuclear PR (A or B isoforms) mRNA expression and mPRα protein expression in a panel of commonly used ovarian cancer cell lines. In contrast to mPR action in breast cancer cells, progesterone alone failed to induce changes in cyclic adenosine monophosphate (cAMP) levels in ovarian cancer cells. However, progesterone enhanced cAMP production by β(1,2)-adrenergic receptors and increased isoproterenol-induced transcription from a cAMP response element (CRE)-driven reporter gene. Independently of β-adrenergic signaling, we additionally observed activation of both JNK1/2 and p38 MAPK in response to progesterone alone. This finding was supported by the results of a screen for potential mPR gene targets. Progesterone induced a significant increase in transcription of the pro-apoptotic marker BAX, whose activity and expression has been linked to JNK1/2 and p38 signaling. Inhibitors of JNK, but not p38, blocked progesterone-induced BAX expression. Taken together, these observations implicate at least two distinct signaling pathways that may be utilized by mPRs in ovarian cancer cells that exhibit regulatory genomic changes. These studies on mPR signaling in ovarian cancer lay the foundation for future work aimed at understanding how progesterone exerts its anti-tumorigenic effects in the ovary and suggest that pharmacologic activation of mPRs, abundantly expressed in ovarian cancers, may provide a new treatment option for patients with advanced stage disease.

Antiprogestin mifepristone inhibits the growth of cancer cells of reproductive and non-reproductive origin regardless of progesterone receptor expression

Background

Mifepristone (MF) has been largely used in reproductive medicine due to its capacity to modulate the progesterone receptor (PR). The study of MF has been expanded to the field of oncology; yet it remains unclear whether the expression of PR is required for MF to act as an anti-cancer agent. Our laboratory has shown that MF is a potent inhibitor of ovarian cancer cell growth. In this study we questioned whether the growth inhibitory properties of MF observed in ovarian cancer cells would translate to other cancers of reproductive and non-reproductive origin and, importantly, whether its efficacy is related to the expression of cognate PR.

Methods

Dose-response experiments were conducted with cancer cell lines of the nervous system, breast, prostate, ovary, and bone. Cultures were exposed to vehicle or increasing concentrations of MF for 72 h and analysed for cell number and cell cycle traverse, and hypodiploid DNA content characteristic of apoptotic cell death. For all cell lines, expression of steroid hormone receptors upon treatment with vehicle or cytostatic doses of MF for 24 h was studied by Western blot, whereas the activity of the G1/S regulatory protein Cdk2 in both treatment groups was monitored in vitro by the capacity of Cdk2 to phosphorylate histone H1.

Results

MF growth inhibited all cancer cell lines regardless of tissue of origin and hormone responsiveness, and reduced the activity of Cdk2. Cancer cells in which MF induced G1 growth arrest were less susceptible to lethality in the presence of high concentrations of MF, when compared to cancer cells that did not accumulate in G1. While all cancer cell lines were growth inhibited by MF, only the breast cancer MCF-7 cells expressed cognate PR.

Conclusions

Antiprogestin MF inhibits the growth of different cancer cell lines with a cytostatic effect at lower concentrations in association with a decline in the activity of the cell cycle regulatory protein Cdk2, and apoptotic lethality at higher doses in association with increased hypodiploid DNA content. Contrary to common opinion, growth inhibition of cancer cells by antiprogestin MF is not dependent upon expression of classical, nuclear PR.

Decreased progesterone receptor isoform expression in luteal phase fallopian tube epithelium and high-grade serous carcinoma

We previously reported that BRCA1/2-mutated fallopian tube epithelium (FTE) collected during the luteal phase exhibits gene expression profiles more closely resembling that of high-grade serous carcinoma (HGSC) specimens than FTE collected during the follicular phase or from control patients. Since the luteal phase is characterised by high levels of progesterone, we determined whether the expression of progesterone receptor (PR) and PR-responsive genes was altered in FTE obtained from BRCA mutation carriers during the luteal phase of the menstrual cycle. RT-qPCR confirmed a decreased expression of PR mRNA in FTE during the luteal phase relative to follicular phase, in both BRCA1/2 mutation carriers and control patients. Immunohistochemistry using isoform-specific antibodies confirmed a low level of both PR-A and PR-B in HGSC and a lower level of staining in FTE samples obtained during the luteal phase compared with the follicular phase. No significant difference in PR-A or PR-B staining was found based on patient BRCA mutation status. Analysis of our previously reported gene expression profiles based upon known PR-A- and PR-B-specific target genes did not partition samples by BRCA mutation status, indicating that overall FTE PR response is not altered in BRCA mutation carriers. HGSC samples grouped separately from other samples, consistent with the observed loss of PR expression. These findings indicate no overall difference in PR signalling in FTE as a function of BRCA mutation status. Thus, the molecular similarity of BRCA1/2-mutated luteal phase FTE and HGSC likely results from an altered response to luteal phase factors other than progesterone.

Steroid hormone receptors in cancer development: a target for cancer therapeutics

The steroid hormone receptors (SHRs) are ligand-dependent intracellular transcription factors that are known to influence the development and growth of many human cancers. SHRs pass signals from a steroid/hormone to the target genes by interacting with specific response element DNA sequences and various coregulatory proteins that consists of activators and/or corepressors. Disruptions in physiological functions of SHRs leads to several types of malignancies such as breast cancer, leukemia and lymphoma, prostate cancer, ovarian cancer, and lung cancer among others. Steroids/hormones/SHRs and their coregulators have opened up a unique window for novel steroid-based targeted therapies for cancer. Thus, dysregulation of SHR signaling in cancers compared with normal tissues can be exploited to target drugs that prevent and treat human cancers. In recent years, hormonal therapy has made a major contribution to the treatment of several cancers including reduced recurrence rates and longer survival rates. Development of various steroid receptor modulators and their potential therapeutic efficacies has provided us a great opportunity to effectively manage diseases like cancer in future. In this review article, we have summarized up-to-date knowledge of the role of SHRs in the development and progression of cancers, and potential endocrine-based therapeutic approaches to tackle these diseases.

Expressions of estrogen and progesterone receptors in epithelial ovarian cancer: a clinicopathologic study

Although estrogen (ER) and progesterone (PR) receptors are well recognized as important prognostic indicators of breast and endometrial cancers, their clinical significance in epithelial ovarian cancer is not clear with the limited data from only few immunohistochemical studies. The aim of this study was to evaluate the expressions of ER and PR in patients with epithelial ovarian cancer who were treated in our institution during the period 1996 to 2003. Their associations with clinicopathologic factors of age, stage, histologic subtypes, and grade and their prognostic role to survivals were also examined. Among 106 subjects included in the study, ER and PR expressions were found in 39.6% and 33.0%, respectively, with the corresponding highest expression in serous and endometrioid carcinomas. Estrogen receptor expression had a significant association with age older than 60 years, non-clear cell carcinomas, and high-grade tumors, whereas PR expression showed a significant association with non-clear cell carcinomas and a better response to first-line chemotherapy. Progesterone receptor expression was a favorable prognostic factor to both progression-free and overall survivals from univariable but not multivariable analyses. Expression of ER or any combination of ER/PR subgroups did not have a significant impact on survivals.

The presence and role of progesterone receptor in the ovaries of postmenopausal women who have not applied hormone replacement therapy

At present, not much is known about progesterone receptor (PR) expression and localization in postmenopausal women ovaries. In the ovaries of reproductive age women, PR is localized in internal theca and granulosa cells, corpus luteum, ovary surface epithelium (OSE) and in stroma. PR expression depends on the serum concentration of progesterone, estrogen, gonadotropin and androgen. The goal of the conducted studies was to examine PR localization and expression in the ovaries of postmenopausal women who have not applied hormone replacement therapy so far. Also, the correlation was examined between PR expression and localization in the ovaries, steroid and gonadotropin hormone serum concentrations, and influence of the time from the last menstruation. The material came from 50 postmenopausal women who had their ovaries removed due to non-neoplastic diseases. The women were divided into 3 groups (A, B, C) depending on the time from the last menstruation. The follitropin (FSH), luteotropin (LH), estradiol (E2), testosterone (T), androstendione (A) and dehydroepiandrosterone sulphate (DHEAS) concentrations in blood plasma were measured. Monoclonal mouse anti-human PR antibody was used for immunohistochemical detection (examination involved 50 postmenopausal ovaries). Between particular groups, E2 serum concentrations did not differ, but FSH, LH, T, A, DHEAS serum concentrations were significantly different. Immunohistochemical nuclear localization of PR in postmenopausal women ovaries was observed. PR expression was similar in all three groups (A, B, C). PR expression was observed in OSE nuclei and invaginations cysts deriving from the isolation of invaginated epithelium and metaplastic columnar epithelium and in stroma. In the ovaries of postmenopausal women who have not applied hormone replacement therapy so far, PR was detected in all three groups. Its expression did not depend on the time from menopause and was similar in all examined groups. FSH, LH, T, A, DHEAS serum concentrations did not influence PR expression.

Progesterone facilitates cisplatin toxicity in epithelial ovarian cancer cells and xenografts

OBJECTIVES

The underlying premise of these investigations was that the lipophilic hormone progesterone, which partitions into and (at relatively high concentrations) impedes the fluid mechanics of the plasmalemma, would perturb integral associations between membrane lipids and exporter pumps that otherwise confer drug resistance. That progesterone can affect susceptibility of ovarian adenocarcinoma cells and xenografts to cisplatin was tested.

METHODS

The cisplatin-resistant human cell lines SKOV-3 and OVCAR-3 were treated for 24 hours with cisplatin (0.1 microg/ml)+/-progesterone (0.01, 0.1 microg/ml). Cytotoxicity and platinum were measured by MTT assay and inductively coupled plasma mass spectrometry, respectively. Athymic mice were inoculated intraperitoneal (ip) with SKOV-3 cells. Cisplatin (2 mg/kg/week)+/-progesterone (25 mg sustained-release pellet) regimens were initiated ip at one week (when micrometastases were present) and continued to six weeks post-xenograft. Tumor burdens, histopathology, and platinum concentrations were assessed upon necropsy at 24 hours after the final injection of cisplatin.

RESULTS

There were no significant in vitro/vivo anticancer effects of cisplatin alone. High-dose progesterone enhanced platinum accretion and induced drug toxicity in both cell lines. Tumorigenesis was suppressed by cisplatin+progesterone. The treatment synergy was related to elevated tumor platinum and morphological evidence of apoptosis.

CONCLUSION

It appears that the addition of progesterone to ovarian cancer therapeutic modalities represents a step in improving responses.

Expression profile of heptahelical putative membrane progesterone receptors in epithelial ovarian tumors

A novel class of putative progestin binding proteins has been recently identified as potential mediators of rapid nongenomic hormone actions. The proteins designated membrane progestin receptor (mPR) alpha, beta, and gamma were initially discovered in fish and shown to have a role in oocyte maturation. The predicted multiple membrane spanning domain structure of the mPRs resembles that of heptahelical G-protein-coupled receptors. Phylogenetic analysis indicated that the mPRs belong to the large progestin and adiponectin Q receptor (PAQR) gene family. Based on the reported expression of the 3 mPRs in hormone-responsive tissues of the female reproductive tract and on the role of steroid hormones in cancer, we investigated the expression of these novel progestin receptors in epithelial tumors of the ovary. The transcript levels of the 3 human mPR/PAQRs were assessed by semiquantitative reverse transcriptase polymerase chain reaction in 28 ovarian samples, including normal tissues, cystadenomas, borderline tumors, and common types of ovarian carcinomas. Two of the 3 transcripts for the mPR/PAQRs proteins appeared differentially expressed in the tumors examined. Expression of mPR alpha and beta was demonstrated in ovarian tumors at both messenger RNA and protein level, and their expression appeared to be independent of the expression of the classic nuclear progestin receptors. Expression of mPR gamma (PAQR V) was elevated in endometrioid and clear cell carcinomas, 2 related neoplastic counterparts of hormonally responsive tissues, suggesting a potential role of the mPR/PAQRs in the pathogenesis of epithelial ovarian tumors.

Regulation of ovarian cancer cell viability and sensitivity to cisplatin by progesterone receptor membrane component-1

CONTEXT

Progesterone (P4) influences ovarian cancer cells by an unknown mechanism.

OBJECTIVE

The objective was to determine whether P4 acts through progesterone receptor membrane component-1 (PGRMC1) in ovarian cancers.

DESIGN, SETTING AND PATIENTS

Archival tissue and cDNA provided by OriGene were used for expression studies. In vitro experiments were conducted with Ovcar-3 cells.

MAIN OUTCOME MEASURES

PCR, Western blot, and immunohistochemistry were used to measure expression of PGRMC1 and nuclear progesterone receptor (PGR). PGRMC1's role in regulating the viability of ovarian cancers was assessed by overexpressing PGRMC1, depleting PGRMC1 using small interfering RNA, and attenuating PGRMC1's action with a blocking antibody. Apoptosis was determined by 4',6'-diamino-2-phenylindole staining.

RESULTS

PGRMC1 mRNA increased and PGR mRNA decreased in advanced stages of ovarian cancer. Unlike PGR, PGRMC1 was expressed in virtually every cancer cell within the tumor. A similar relationship between PGRMC1 and PGR was observed in Ovcar-3 cells. In these cells P4 suppressed apoptosis induced by either serum withdrawal or cisplatin (CDDP). Moreover, in the presence of P4, the following occurs: 1) overexpression of PGRMC1 reduces the effectiveness of CDDP, 2) depletion of PGRMC1 with small interfering RNA enhances the effects of CDDP, and 3) PGRMC1 antibody treatment increases the apoptotic response to CDDP.

CONCLUSIONS

These findings indicate that PGRMC1 plays an important role in promoting ovarian cancer cell viability and that attenuating PGRMC1's action makes the ovarian cancer cells more sensitive to CDDP. These data suggest that targeted depletion of PGRMC1 could be useful as an adjunct to CDDP therapy.

Review of the etiology of breast cancer with special attention to organochlorines as potential endocrine disruptors

Breast cancer is the most frequently diagnosed cancer among Canadian women, accounting for about 30% of all new cancer cases each year. Although the incidence of breast cancer has increased over the past 50 years, the cause of this rise is unknown. Risk factors for breast cancer may be classified into four broad categories: (1) genetic/familial, (2) reproductive/hormonal, (3) lifestyle, and (4) environmental. Established risk factors for breast cancer include older age, later age at first full-term pregnancy, no full-term pregnancies, postmenopausal obesity, and genetic factors. However, these known risk factors cannot account for the majority of cases. In the early 1990s, it was suggested that exposure to some environmental chemicals such as organochlorine compounds may play a causal role in the etiology of breast cancer through estrogen-related pathways. The relationship between organochlorines and breast cancer risk has been studied extensively in the past decade and more, and at this point there is no clear evidence to support a causal role of most organochlorine pesticides in the etiology of human breast cancer, but more evidence is needed to assess risk associated with polychlorinated biphenyls (PCBs). Future studies need to consider the combined effects of exposures, concentrate on vulnerable groups such as those with higher levels of exposure, only consider exposures occurring during the most etiologically relevant time periods, and more thoroughly consider gene-environment interactions.

Risk factors for ovarian cancer: an overview with emphasis on hormonal factors

Ovarian cancer is the fifth most frequently occurring cancer among women and leading cause of gynecological cancer deaths in North America. Although the etiology of ovarian cancer is not clear, certain factors are implicated in the etiology of this disease, such as ovulation, gonadotropic and steroid hormones, germ cell depletion, oncogenes and tumor suppressor genes, growth factors, cytokines, and environmental agents. Family history of breast or ovarian cancer is a prominent risk factor for ovarian cancer, with 5-10% of ovarian cancers due to heritable risk. Reproductive factors such as age at menopause and infertility contribute to greater risk of ovarian cancer, whereas pregnancy, tubal ligation, and hysterectomy reduce risk. Oral contraceptive (OC) use has clearly been shown to be protective against ovarian cancer. In contrast, large epidemiologic studies found hormone replacement therapy (HRT) to be a greater risk factor for ovarian cancer. The marked influence of hormones and reproductive factors on ovarian cancer suggests that endocrine disrupters may impact risk; however, there is a notable lack of research in this area. Lifestyle factors such as cigarette smoking, obesity, and diet may affect ovarian cancer risk. Exposure to certain environmental agents such as talc, pesticides, and herbicides may increase risk of ovarian cancer; however, these studies are limited. Further research is needed to strengthen the database of information from which an assessment of environmental and toxicological risk factors for ovarian cancer can be made.

Histological and Immunohistochemical Evaluation of Canine Ovary

In the present study, 15 canine ovaries without morphological lesions were examined histologically and immunohistochemically by using a large number of proteins including AE1/AE3, cytokeratin7 (CK7), CK13, CK20, vimentin, desmin, alpha smooth muscle actin (alphaSMA), calponin, S100, Neurofilaments, Inhibinalpha, placental alkaline phosphatase (PLAP) and neuron-specific enolase. Ovarian structures observed in this study included surface epithelium (SE), cortical tubules (CT), tunica albuginea (TA), stromal cells (SC), internal endocrine cells (IE), rete ovarii (RO) and fallopian tubes (FT). SE, CT, RO and FT were broadly immunoreactive for desmin. Besides AE1/AE3 and vimentin, desmin was also closely linked to these structures. Rete ovarii forming a reticular structure showed a positive reaction to S100. Surface epithelium was immunoreactive for PLAP at a significantly high level. In conclusion, these results indicate a specific segment of immunoreactivity as well as the broad range of immunoreactivity in canine ovary. The distinct patterns of immunoreactive for various kinds of proteins will play an important role in facilitating their identification and discrimination even in a normal canine ovary with a complex structure.

Mifepristone inhibits ovarian cancer cell growth in vitro and in vivo

PURPOSE

These studies were designed to determine whether the synthetic steroid mifepristone inhibits ovarian cancer growth in vitro and in vivo and the molecular mechanisms involved.

EXPERIMENTAL DESIGN

The effect of mifepristone on ovarian cancer cell growth in vitro was studied in ovarian cancer cell lines of different genetic backgrounds (SK-OV-3, Caov-3, OV2008, and IGROV-1). In addition, the growth inhibition capacity of mifepristone on ovarian carcinoma xenografts was tested in nude mice.

RESULTS

Mifepristone inhibited ovarian cancer cell proliferation in a dose- and time-dependent manner. The cytostatic effect of mifepristone was confirmed in a clonogenic survival assay and was not linked to loss of viability. Mifepristone blocked DNA synthesis, arrested the cell cycle at the G(1)-S transition, up-regulated cyclin-dependent kinase (cdk) inhibitors p21(cip1)and p27(kip1), down-regulated transcription factor E2F1, decreased expression of the E2F1-regulated genes cdk1 (cdc2) and cyclin A, and modestly decreased cdk2 and cyclin E levels. The abrupt arrest in cell growth induced by mifepristone correlated with reduced cdk2 activity, increased association of cdk2 with p21(cip1) and p27(kip1), increased nuclear localization of the cdk inhibitors, and reduced nuclear abundance of cdk2 and cyclin E. In vivo, mifepristone significantly delayed the growth of ovarian carcinoma xenografts in a dose-dependent manner and without apparent toxic effects for the animals.

CONCLUSIONS

These preclinical studies show that mifepristone is effective as a single agent in vitro and in vivo, inhibiting the growth of human epithelial ovarian cancer cells. Mifepristone markedly reduces cdk2 activity likely due to increased association of cdk2 with the cdk inhibitors p21(cip1) and p27(kip1) and reduced nuclear cdk2/cyclin E complex availability. Acting as a cytostatic agent, mifepristone promises to be of translational significance in ovarian cancer therapeutics.

Expression of Organic Cation Transporter SLC22A16 in Human Epithelial Ovarian Cancer

The SLC22A16 is one of the newly isolated organic cation transporters, which is responsible for uptake and transport of adriamycin into cells. Adriamycin is considered to be an active agent for ovarian cancer. Recently, the benefit of adding adriamycin to the current standard regimen, paclitaxel and platinum, is evaluated to improve the outcome of patients with ovarian cancer. Therefore, we examined the expression of SLC22A16 in ovarian cancers. Twelve ovarian carcinoma cell lines were used for immunoblotting and reverse transcription-polymerase chain reaction to confirm the expression of SLC22A16 mRNA and protein. Five normal ovaries, 12 ovarian adenomas, and 94 ovarian cancer cases were obtained from patients after surgical therapy. The specimens were used for immunohistochemistry. The median value of relative SLC22A16 gene expression in cell lines derived from clear-cell adenocarcinoma was significantly higher than that in cell lines from other histologies (P < 0.001). Expression of SLC22A16 protein was also detected in cell lines derived from clear-cell adenocarcinoma. The SLC22A16 immunoreactivity was detected in 15 (16%) of 94 epithelial ovarian cancer, 1 (8.3%) of 12 benign adenomas, but 0 (0%) of 5 normal ovary cases. In ovarian cancer tissues, SLC22A16 immunoreactivity was detected in 2 (5%) of 38 serous adenocarcinoma, 1 (6.7%) of 15 endometrioid adenocarcinoma, 0 (0%) of 14 mucinous adenocarcinoma, and 12 (46.2%) of 26 clear-cell adenocarcinoma (P < 0.0001, clear-cell vs other histologies). In conclusion, SLC22A16 was abundantly expressed in clear-cell adenocarcinoma. Our results suggest that adriamycin-related chemicals that are taken up via SLC22A16 may have the potential to be effective against clear-cell adenocarcinoma.

Gonadotropins and ovarian cancer

Ovarian epithelial cancer (OEC) accounts for 90% of all ovarian cancers and is the leading cause of death from gynecological cancers in North America and Europe. Despite its clinical significance, the factors that regulate the development and progression of ovarian cancer are among the least understood of all major human malignancies. The two gonadotropins, FSH and LH, are key regulators of ovarian cell functions, and the potential role of gonadotropins in the pathogenesis of ovarian cancer is suggested. Ovarian carcinomas have been found to express specific receptors for gonadotropins. The presence of gonadotropins in ovarian tumor fluid suggests the importance of these factors in the transformation and progression of ovarian cancers as well as being prognostic indicators. Functionally, there is evidence showing a direct action of gonadotropins on ovarian tumor cell growth. This review summarizes the key findings and recent advances in our understanding of these peptide hormones in ovarian cancer development and progression and their role in potential future cancer therapy. We will first discuss the supporting evidence and controversies in the "gonadotropin theory" and the use of animal models for exploring the involvement of gonadotropins in the etiology of ovarian cancer. The role of gonadotropins in regulating the proliferation, survival, and metastasis of OEC is next summarized. Relevant data from ovarian surface epithelium, which is widely believed to be the precursor of OEC, are also described. Finally, we will discuss the clinical applications of gonadotropins in ovarian cancer and the recent progress in drug development.

Promoter methylation status of the Cyclin D2 gene is associated with poor prognosis in human epithelial ovarian cancer

Gene silencing associated with aberrant DNA methylation of promoter CpG islands is one mechanism through which several genes may be inactivated in human cancers. Cyclin D2, a member of the D-type cyclins, implicated in cell cycle regulation, differentiation and malignant transformation, is inactivated due to aberrant DNA methylation in several human cancers. In the present study, we examined the promoter methylation status and expression of Cyclin D2 in human epithelial ovarian cancer, and then determined the relationship between methylation status and various clinicopathological variables. Twelve ovarian cancer cell lines and 71 surgical specimens were examined by methylation-specific polymerase chain reaction and quantitative reverse transcription-polymerase chain reaction to evaluate the methylation status and expression of the Cyclin D2 gene. The relationship between methylation status and various clinicopathological variables was evaluated using statistical analysis. Aberrant methylation of Cyclin D2 was present in five of 12 ovarian cancer cell lines and 16 of 71 primary ovarian cancer tissues. In five cell lines with methylation, expression of the Cyclin D2 gene tended to be lower than in cell lines without methylation. In ovarian cancer tissues, methylation bands were detected in 16 of 71 cases. The methylation status of Cyclin D2 was associated with advanced stage and a residual tumor size (>2 cm) (P = 0.027 and P = 0.031, respectively). Based on univariate analysis, patients with aberrant methylation of the Cyclin D2 promoter had a significantly worse chance of disease-free survival than those without methylation (P = 0.021). Our results suggest that aberrant promoter methylation of the Cyclin D2 gene is significantly associated with patient prognosis in epithelial ovarian cancer.

Expression of Organic Cation Transporter SLC22A16 in Human Endometria

SLC22A16 is one of newly isolated organic cation transporters, which is responsible for uptake and transport of adriamycin into cells. Adriamycin is one of the key drugs for treatment of endometrial cancer. Therefore, we examined expression of SLC22A16 in human endometrium and its disorders. Protein and mRNA expression levels of SLC22A16 were examined in 124 endometrial cancer specimens, 25 normal endometrial tissue samples (15 in proliferative phase, 10 in secretory phase), and 7 endometrial cancer cell lines using immunohistochemical analysis and reverse transcription-polymerase chain reaction. Changes in SLC22A16 mRNA expression level after progesterone exposure were also examined. Immunohistochemical analysis showed that SLC22A16 protein was highly expressed in endometrium during the normal secretory phase, but its level was significantly reduced in the proliferative phase. SLC22A16 protein was detected in 59 of 124 (48%) endometrial cancer specimens and 3 of 7 (43%) endometrial cancer cell lines. The mRNA levels measured by quantitative reverse transcription-polymerase chain reaction were comparable with levels of protein expression. Furthermore, SLC22A16 mRNA levels were increased in endometrial cancer cell lines in the presence of progesterone. In conclusion, SLC22A16 is expressed in various endometrial tissues. Its expression level is high during the secretory phase and may be regulated by progesterone. Our findings also suggest that it may be possible to use progestins to increase the response of endometrioid endometrial carcinoma with SLC22A16 expression to adriamycin-based chemotherapeutic regimens.

Progesterone receptor isoforms as a prognostic marker in human endometrial carcinoma

The possible role of specific progesterone receptor (PR) isoforms (PRA and PRB) as predictive factors in endometrial carcinoma is unclear. The present study was undertaken to evaluate the clinical significance of intratumoral PR isoform status in patients with endometrioid endometrial carcinoma. We studied 103 cases of endometrioid endometrial carcinoma using immunohistochemistry. We correlated the findings with various clinicopathological parameters of the patients. PRA and PRB immunoreactivity was detected in 51/103 (48.5%) and 79/103 (76.7%) of carcinoma cases, respectively. A significant positive correlation was detected between the status of PRB immunoreactivity and the amount of PRB mRNA by real-time reverse transcription-polymerase chain reaction (P = 0.012). PR isoform expression was significantly lower in the cases with higher histological grade (P = 0.0001 and P = 0.002, for PRA and PRB, respectively). Cases that were negative for either one or both PR isoforms were significantly associated with shorter disease-free and overall survival of the patients. The absence of either one or both of these two PR isoforms was detected in all nine patients who died (100.0%), whereas the absence of these immunoreactivities was detected only in 43 of 94 (45.7%) patients who had lived during the same period. In addition, multivariate analysis demonstrated that an absence of PRA immunoreactivity was an independent risk factor in disease-free survival of the patients (P = 0.0258). The results of our study demonstrated that loss or absence of PR isoform expression determined by immunohistochemistry could become an important prognostic indicator in patients with endometrioid endometrial carcinoma.

Endocrine signaling in ovarian surface epithelium and cancer

Ovarian cancer is the sixth most common cancer and the fifth leading cause of cancer-related death among women in developed countries. Greater than 85% of human ovarian cancer arises within the ovarian surface epithelium (OSE), with the remainder derived from granulosa cells or, rarely, stroma or germ cells. The pathophysiology of ovarian cancer is the least understood among all major human malignancies because of a poor understanding of the aetiological factors and mechanisms of ovarian cancer progression. There is increasing evidence suggesting that several key reproductive hormones, such as GnRH, gonadotrophins and sex steroids, regulate the growth of normal OSE and ovarian cancer cells. The objective of this review was to highlight the effects of these endocrine factors on ovarian cancer cell growth and to summarize the signalling mechanisms involved in normal human OSE and its neoplastic counterparts.

DNA Methylation Profiles of Female Steroid Hormone-Driven Human Malignancies

Tumor DNA contains valuable clues about the origin and pathogenesis of human cancers. Alterations in DNA methylation can lead to silencing of genes associated with distinct tumorigenic pathways. These pathway-specific DNA methylation changes help define tumor-specific DNA methylation profiles that can be used to further our understanding of tumor development, as well as provide tools for molecular diagnosis and early detection of cancer. Female sex hormones have been implicated in the etiology of several of the women's cancers including breast, endometrial, ovarian, and proximal colon cancers. We have reviewed the DNA methylation profiles of these cancers to determine whether the hormonal regulation of these cancers results in specific DNA methylation alterations. Although subsets of tumors in each of these four types of cancers were found to share some DNA methylation alterations, we did not find evidence for global hormone-specific DNA methylation alterations, suggesting that female sex hormones may participate in different tumorigenic pathways that are associated with distinct DNA methylation-based molecular signatures. One such pathway may include MLH1 methylation in the context of the CpG island methylator phenotype.

Expression of estrogen-responsive finger protein (Efp) is associated with advanced disease in human epithelial ovarian cancer

OBJECTIVE

The estrogen-responsive ring finger protein (Efp) gene, one of estrogen receptor (ER) target genes, is considered to be essential for estrogen-dependent cell proliferation. To understand the estrogenic action on ovarian cancer, we studied the relationships between Efp and ERs expressions and the correlations of Efp expression with clinicopathological parameters in epithelial ovarian cancer.

METHODS

The protein expressions for Efp, ERalpha and ERbeta were examined by immunoblotting in 12 ovarian cancer cell lines. Efp mRNA expressions were evaluated by quantitative RT-PCR in 12 ovarian cancer cell lines. A total of 100 surgical specimens diagnosed as epithelial ovarian cancer were examined immunohistochemically using antibodies for Efp, ERalpha and ERbeta.

RESULTS

Efp protein was detected in 8 out of 12 cell lines. In Efp protein-positive cell lines, Efp mRNA was expressed higher than that in negative (P=0.021). All of the Efp protein-positive cell lines simultaneously expressed either ERalpha or ERbeta protein. By immunohistochemical staining, Efp immunoreactivity was detected in 63 out of 100 ovarian cancer specimens and positive signals were in the cytoplasm of carcinoma cells. There were significant correlations between Efp and ERalpha, ERbeta immunoreactivity (Efp and ERalpha, P=0.022; Efp and ERbeta, P=0.032). Efp expression was significantly higher in a subgroup with serous adenocarcinoma (P=0.010) and with advanced disease (P=0.026). No significant relationship was detected between Efp immunoreactivity and overall survival.

CONCLUSION

The expression of Efp was detected in human epithelial ovarian cancer and high expression of Efp was correlated with advanced disease and serous adenocarcinoma, and ERs status.

Hormonal treatments and epithelial ovarian cancer risk

Exogenous sex hormones are widely used by women either for pregnancy prevention, as part of infertility treatment, or for treatment of menopausal symptoms. The role of these hormones in the development of ovarian cancer has been vastly explored. The protective effect of combined oral contraceptive pill is confirmed in multiple studies, but it is not clear whether this protection also covers women with a genetic predisposition to ovarian cancer. There is no conclusive evidence of infertility treatments increasing ovarian cancer risk, but infertility as such is a risk factor. Currently available data suggest that long-term users of hormone replacement therapy may have a slightly increased risk for ovarian cancer compared to women who have never used estrogen. The risk might particularly involve the endometrioid type of ovarian cancer. Most data on ovarian cancer and estrogen comes from epidemiological studies, since the normally high concentrations of estrogens in ovarian tissue and follicular fluid make direct biologic studies on the effects of exogenous estrogens on the ovarian cell difficult. This review discusses the risk of ovarian cancer associated with the use of sex steroid hormones, with special emphasis on the possible risk associated with estrogens.

Expression of estrogen receptor-related receptors, a subfamily of orphan nuclear receptors, as new tumor biomarkers in ovarian cancer cells

A subfamily of orphan receptors, estrogen receptor-related receptors (ERRs), has been demonstrated to modulate the transcription of some estrogen responsive genes via variant estrogen response elements (EREs). This study was conducted to determine whether human ERRalpha, ERRbeta, and ERRgamma might be involved in the tumorigenesis of ovarian cancer. RT-PCR was performed to analyze the expression of hERRalpha, hERRbeta, hERRbeta-2, and hERRgamma mRNA in five ovarian cancer cell lines as well as 33 samples of ovarian cancer and 12 samples of normal ovary. Serum CA-125 levels were also analyzed in all samples by ELISA. Progression-free survival and overall survival of patients with different expression of ERRs were analyzed by the Kaplan-Meier method. To analyze the subcellular localization of ERRalpha, a green fluorescent protein (GFP)-reporter plasmid of hERRalpha was constructed and transfected into the ovarian cancer cell line OVCAR-3. Expression of hERRalpha-GFP fusion protein was observed in the nucleus of OVCAR-3 ovarian cancer cell lines. We observed increased expression of hERRalpha mRNA (P = 0.020) and hERRgamma mRNA (P = 0.045) in ovarian cancers compared to normal ovaries. In contrast, hERRbeta was only observed in 9.1% of ovarian cancers. We found a positive correlation between the serum CA-125 levels and hERRalpha expression (P = 0.012), but not hERRbeta and hERRgamma expression. Survival analysis showed that the hERRalpha-positive group has a reduced overall survival (P = 0.015), and the ERRgamma-positive group has a longer progression-free survival (P = 0.020). In multivariate analysis, expression of hERRalpha was an independent prognostic factor for poor survival (relative risk, 3.032; 95% CI, 1.27-6.06). Based on our results, ERRs may play an important role in ovarian cancer. hERRalpha may represent a biomarker of poor prognosis, and hERRgamma may be a new therapeutic target in ovarian cancer.

Decreased expression of 14-3-3 sigma is associated with advanced disease in human epithelial ovarian cancer: its correlation with aberrant DNA methylation

PURPOSE

In this study, we examined the promoter methylation status and expression of 14-3-3 sigma and evaluated its clinical significance in epithelial ovarian cancer.

EXPERIMENTAL DESIGN

Twelve ovarian cancer cell lines; 2 ovarian surface epithelial cell lines; and 8 normal, 8 benign, 12 borderline, and 102 ovarian cancer tissues were examined. Methylation-specific PCR, quantitative reverse transcription-PCR, and immunohistochemistry were used to evaluate methylation status and expression of 14-3-3 sigma gene and protein.

RESULTS

Among the 12 ovarian cancer cell lines, the presence of a methylated band was detected in seven cell lines. Median values of relative 14-3-3 sigma gene expression in cancers with methylation (3.27) were significantly lower than those without methylation (16.4; P < 0.001). Treatment of 5-aza-2'-deoxycitidine resulted in the demethylation of the promoter CpG islands and reexpression. All of the normal, benign, and borderline tissues were positive for 14-3-3 sigma protein, and in ovarian cancer tissues, 73.5% (75 of 102) were positive for 14-3-3 sigma protein and was almost consistent with methylation status. Negative immunoreactivity of 14-3-3 sigma was significantly correlated with high age and serous histology, high-grade, advanced-stage residual tumor of >2 cm, high serum CA125, high Ki-67 labeling index, and positive p53 immunoreactivity. 14-3-3 sigma immunoreactivity was significantly associated with overall survival (P = 0.0058).

CONCLUSIONS

Our findings suggest that 14-3-3 sigma is inactivated mainly by aberrant DNA methylation and that it may play an important role in the pathogenesis of epithelial ovarian cancer.

Expression of EBAG9/RCAS1 is associated with advanced disease in human epithelial ovarian cancer

Oestrogen receptor-binding fragment associated gene 9, EBAG9, is an oestrogen-responsive gene that was identified in MCF-7 human breast carcinoma cell line. It is identical to RCAS 1, a cancer cell surface antigen possibly involved in immune escape. In the present study, we examined the expression of EBAG9/RCAS1 in human epithelial ovarian cancer using immunohistochemistry, immunoblotting and reverse transcription–polymerase chain reaction (RT–PCR). A total of 90 epithelial ovarian cancer cases were examined immunohistochemically by means of the antibodies for EBAG9 and ERα. The correlation between EBAG9 immunoreactivity and clinicopathological parameters was examined. mRNA expression of EBAG9 and ERα were evaluated by RT–PCR in 22 cases. The expression for EBAG9 and ERα was examined by immunoblotting in 12 ovarian cancer cell lines. EBAG9 immunoreactivity was detected in the surface and cytoplasm of carcinoma cells in 46 out of 90 cases (51.1%). EBAG9 expression was significantly higher in serous histology (P=0.0402) and advanced disease (P=0.0206). No significant relationship was detected between EBAG9 immunoreactivity and overall survival (P=0.689). There was a highly significant correlation between EBAG9 and ER immunoreactivity (P<0.0001). The EBAG9 mRNA was detected in 20 out of 22 cases. In all of the cases that were positive for ERα mRNA, they were also positive for EBAG9 mRNA. Immunoreactive band corresponding to EBAG9 was detected in 11 out of 12 of ovarian cancer cell lines, and was consistent with ERα expression. In conclusion, the wide distribution of EBAG9 and its relation to advanced disease suggest that this protein may play important roles in epithelial ovarian cancer.

Nuclear receptor DAX-1 in human common epithelial ovarian carcinoma: an independent prognostic factor of clinical outcome

DAX-1 is a member of the nuclear receptor superfamily and is thought to be involved in the regulation of steroidogenesis. Its expression has been detected primarily in endocrine neoplasms such as adrenocortical as well as pituitary tumors in human, but its biological roles have not been examined well in sex steroid-dependent neoplasms. The aim of this study is to detect the expression of DAX-1 in common epithelial ovarian carcinomas in order to evaluate its possible biological significance. DAX-1 immunoreactivity was examined using immunohistochemistry. The correlation between the status of DAX-1 immunoreactivity and clinicopathological parameters and disease-free survival of the patients in a series of 60 cases of common epithelial ovarian carcinoma was examined. The status of DAX-1 immunoreactivity was evaluated using H score. DAX-1 immunoreactivity was widely detected in the nuclei of common epithelial ovarian carcinoma cells. There was a significant positive correlation between DAX-1 immunoreactivity and clinical staging (P = 0.0241), tumor grade (P = 0.0115), the residual size of the tumor (P = 0.0014) and Ki-67 labeling index (P = < 0.0001). In univariate survival analysis, a significant association was detected between DAX-1 immunoreactivity and shortened patient survival (P = 0.0157). Other significant prognostic parameters were clinical stage, residual size of tumor and Ki-67. In multivariate analysis, DAX-1 immunoreactivity, clinical stage, residual size of tumor and Ki-67 all turned out to be independent prognostic factors for shortened survival. In conclusion, DAX-1 immunoreactivity is considered to be a new independent marker of poor prognosis or adverse clinical outcome in patients with epithelial ovarian carcinoma, possibly through altering in situ steroids production.

Estrogen, progesterone and epithelial ovarian cancer

Ovarian carcinoma (OCa) continues to be the leading cause of death due to gynecologic malignancies and the vast majority of OCa is derived from the ovarian surface epithelium (OSE) and its cystic derivatives. Epidemiological evidence strongly suggests that steroid hormones, primarily estrogens and progesterone, are implicated in ovarian carcinogenesis. However, it has proved difficult to fully understand their mechanisms of action on the tumorigenic process. New convincing data have indicated that estrogens favor neoplastic transformation of the OSE while progesterone offers protection against OCa development. Specifically, estrogens, particularly those present in ovulatory follicles, are both genotoxic and mitogenic to OSE cells. In contrast, pregnancy-equivalent levels progesterone are highly effective as apoptosis inducers for OSE and OCa cells. In this regard, high-dose progestin may exert an exfoliation effect and rid an aged OSE of pre-malignant cells. A limited number of clinical studies has demonstrated efficacies of antiestrogens, aromatase inhibitors, and progestins alone or in combination with chemotherapeutic drugs in the treatment of OCa. As a result of increased life expectancy in most countries, the number of women taking hormone replacement therapies (HRT) continues to grow. Thus, knowledge of the mechanism of action of steroid hormones on the OSE and OCa is of paramount significance to HRT risk assessment and to the development of novel therapies for the prevention and treatment of OCa.