Functional deficiency of DNA repair gene EXO5 results in androgen-induced genomic instability and prostate tumorigenesis.

Germline mutations of DNA double-strand break (DSB) response and repair genes that drive tumorigenesis could be a major cause of prostate cancer (PCa) heritability. In this study, we demonstrated the role of novel exonuclease 5 (EXO5) gene in androgen-induced double strand breaks repair via homology-directed repair pathway and prostate tumorigenesis. Using whole-exome sequencing of samples from 20 PCa families, with three or more siblings diagnosed with metastatic PCa, we identified mutations in 31 genes involved in DSB response and repair. Among them, the L151P mutation in the exonuclease 5 (EXO5) gene was present in all affected siblings in three PCa families. We found two other EXO5 SNPs significantly associated with risk of PCa in cases-controls study from databases of genotype and phenotype (dbGaP), which are in linkage disequilibrium (D' = 1) with Exo5 L151P found in PCa family. The L151 residue is conserved across diverse species and its mutation is deleterious for protein functions, as demonstrated by our bioinformatics analyses. The L151P mutation impairs the DNA repair function of EXO5 due to loss of nuclease activity, as well as failure of nuclear localization. CRISPR elimination of EXO5 in a PCa cell line impaired homology-directed recombination repair (HDR) and caused androgen-induced genomic instability, as indicated by frequent occurrence of the oncogenic fusion transcript TMPRSS2-ERG. Genetic and functional validation of the EXO5 mutations indicated that EXO5 is a risk gene for prostate tumorigenesis, likely due to its functions in HDR.

Immunization against environmental chemical carcinogens: Pro and contra.

The problems of immunoprotection from the environmental chemical carcinogens are discussed. The main experimental argument pro active immunization against carcinogens is a possibility of specific mucosal antibodies (Abs) to inhibit the penetration of carcinogens from environment and to stimulate its excretion with the following decreasing of carcinogen-DNA adducts levels. Hypothesis of cancer immunostimulation after active immunization against carcinogens is based on a high cancer risk in persons with high levels of serum Abs specific to environmental carcinogens coupled with high levels of Abs to endogenous steroids stimulating the proliferation of target cells, for example, Abs to benzo[a]pyrene together with Abs to estradiol. The active immunization could increase the cancer risk much more in those persons. The passive immunization could be an alternative safe approach to avoid this problem.

Mouse ER+/PIK3CAH1047R breast cancers caused by exogenous estrogen are heterogeneously dependent on estrogen and undergo BIM-dependent apoptosis with BH3 and PI3K agents.

Estrogen dependence is major driver of ER + breast cancer, which is associated with PI3K mutation. PI3K inhibition (PI3Ki) can restore dependence on ER signaling for some hormone therapy-resistant ER + breast cancers, but is ineffective in others. Here we show that short-term supplementation with estrogen strongly enhanced Pik3caH1047R-induced mammary tumorigenesis in mice that resulted exclusively in ER + tumors, demonstrating the cooperation of the hormone and the oncogene in tumor development. Similar to human ER + breast cancers that are endocrine-dependent or endocrine-independent at diagnosis, tumor lines from this model retained ER expression but were sensitive or resistant to hormonal therapies. PI3Ki did not induce cell death but did cause upregulation of the pro-apoptotic gene BIM. BH3 mimetics or PI3Ki were unable to restore hormone sensitivity in several resistant mouse and human tumor lines. Importantly however, combination of PI3Ki and BH3 mimetics had a profound, BIM-dependent cytotoxic effect in PIK3CA-mutant cancer cells while sparing normal cells. We propose that addition of BH3 mimetics offers a therapeutic strategy to markedly improve the cytotoxic activity of PI3Ki in hormonal therapy-resistant and ER-independent PIK3CA-mutant breast cancer.

Melanoma risk after in vitro fertilization: A review of the literature.

BACKGROUND: The role of female sex hormones in the pathogenesis of malignant melanoma (MM) remains controversial. Although melanocytes appear to be hormonally responsive, the effect of estrogen on MM cells is less clear. Available clinical data does not consistently demonstrate that increased endogenous hormones from pregnancy or increased exogenous hormones from oral contraceptive pills and hormone replacement affect MM prevalence and outcome. OBJECTIVE: We sought to examine potential associations between in vitro fertilization (IVF) and melanoma. METHODS: A literature review was conducted. Primary outcomes were reported as associations between IVF and melanoma risk compared with the general population. Secondary outcomes included associations stratified by type of IVF regimen and subgroup, such as parous versus nulliparous patients. RESULTS: Eleven studies met our inclusion criteria. Five studies found no increased risk for MM among IVF users compared with the general population. Two studies found an increase in MM in clomiphene users, and 4 studies found an increase in MM among patients who were gravid or parous either before or after IVF. CONCLUSION: The reviewed studies do not reveal consistent patterns of association between IVF and MM among all infertile women. However, the data indicates a potential increased risk for MM in ever-parous patients treated with IVF. High-quality studies including a large number of MM cases that control for well-established MM risk factors are needed to adequately assess the relationship between IVF and MM, particularly among ever-parous women.

Cardiac glycosides and breast cancer risk: A systematic review and meta-analysis of observational studies.

Cardiac glycosides are phytoestrogens and have been linked to the risk of estrogen sensitive cancers such as uterus cancer. However, the association between use of cardiac glycosides and risk of breast cancer remains unclear. We investigated the association between cardiac glycosides use and the risk of breast cancer by systematically reviewing the published literature and performing meta-analyses. A comprehensive literature search was performed using MEDLINE, EMBASE, Web of Science and SCOPUS to identify all relevant articles published up to November 2015. Risk estimates, and accompanying standard errors, for the association between cardiac glycoside use and breast cancer were extracted from identified studies. Meta-analysis models were used to calculate a combined hazard ratio (HR), and 95% confidence interval (CI), and to investigate heterogeneity between studies. In total, nine studies were identified investigating cardiac glycosides use and risk of developing breast cancer. Overall, there was evidence to suggest an association between cardiac glycosides use and breast cancer risk (HR = 1.34; 95% CI 1.25, 1.44; p < 0.001) with little variation in the association between studies (I2 = 16%, p for heterogeneity = 0.30). Results were little altered when analysis was restricted to studies with high quality scores or cohort studies. Overall, there was a 34% increase in breast risk with use of cardiac glycosides but it is unclear whether this association reflects confounding or is causal. Further observational studies are required to examine this association particularly for estrogen receptor positive breast cancer and to explore the role of potential confounding variables.

Zearalenone as an endocrine disruptor in humans.

Zearalenone (ZEA), a fungal mycotoxin, is present in a wide range of human foods. Many animal studies have found ZEA to possess a disruptive effect on the hormonal balance, mainly due to its similarity to naturally-occurring estrogens. With increasing consciousness of the adverse effects of endocrine disruptors on human health, it is becoming more important to monitor ZEA concentrations in food and identify its potential effects on human health. Based on a review of recent studies on animal models and molecular pathways in which ZEA is reported to have an influence on humans, we postulate that ZEA might act as an endocrine disruptor in humans in a similar way to animals. Moreover, its endocrine-disrupting effect might be also a causative factor in carcinogenesis. This review article summarizes the latest knowledge about the influence of ZEA on the human hormonal balance.

Conditional Expression of the Androgen Receptor Increases Susceptibility of Bladder Cancer in Mice.

Bladder cancer represents a significant human tumor burden, accounting for about 7.7% and 2.4% of all cancer cases in males and females, respectively. While men have a higher risk of developing bladder cancer, women tend to present at a later stage of disease and with more aggressive tumors. Previous studies have suggested a promotional role of androgen signaling in enhancing bladder cancer development. To directly assess the role of androgens in bladder tumorigenesis, we have developed a novel transgenic mouse strain, R26hARLoxP/+:Upk3aGCE/+, in which the human AR transgene is conditionally expressed in bladder urothelium. Intriguingly, both male and female R26hARLoxP/+:Upk3aGCE/+ mice display a higher incidence of urothelial cell carcinoma (UCC) than the age and sex matched control littermates in response to the carcinogen, N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). We detect expression of the human AR transgene in CK5-positive and p63-positive basal cells in bladder urothelium. Further analyses of UCC tissues from R26hARLoxP/+:Upk3aGCE/+ mice showed that the majority of tumor cells are of urothelial basal cell origin. Positive immunostaining of transgenic AR protein was observed in the majority of tumor cells of the transgenic mice, providing a link between transgenic AR expression and oncogenic transformation. We observed an increase in Ki67 positive cells within the UCC lesions of transgenic AR mice. Manipulating endogenous androgen levels by castration and androgen supplementation directly affected bladder tumor development in male and female R26hARLoxP/+:Upk3aGCE/+ mice, respectively. Taken together, our data demonstrate for the first time that conditional activation of transgenic AR expression in bladder urothelium enhances carciongen-induced bladder tumor formation in mice. This new AR transgenic mouse line mimics certain features of human bladder cancer and can be used to study bladder tumorigenesis and for drug development.

[Endocrine disruptors, reproduction and hormone-dependent cancers]. / Perturbateurs endocriniens - Reproduction et cancers hormono-dépendants.

Endocrine disruptors are natural or synthetic chemical compounds which are present in the environment and which are able to interfere with hormonal regulation pathways and to induce human health deleterious effects. While their precise implication in human health and diseases is still matter of debates, it becomes likely that they have to be considered as risk factors in numerous chronic diseases: developmental and reproductive defects and hormone dependent cancers (present review), metabolic diseases (obesity and type 2 diabetes), neurodevelopmental or neurodegenerative diseases. Low doses exposure during critical windows of exposure such as foetal, perinatal and peri-pubertal periods, or chronic exposure with bioaccumulation in the adipose tissue, and possible synergic effects of several compounds ("cocktail effect") may participate to the genetic/environment interface suspected to participate to the pathophysiology of many diseases.

Executive Summary to EDC-2: The Endocrine Society's Second Scientific Statement on Endocrine-Disrupting Chemicals.

This Executive Summary to the Endocrine Society's second Scientific Statement on environmental endocrine-disrupting chemicals (EDCs) provides a synthesis of the key points of the complete statement. The full Scientific Statement represents a comprehensive review of the literature on seven topics for which there is strong mechanistic, experimental, animal, and epidemiological evidence for endocrine disruption, namely: obesity and diabetes, female reproduction, male reproduction, hormone-sensitive cancers in females, prostate cancer, thyroid, and neurodevelopment and neuroendocrine systems. EDCs such as bisphenol A, phthalates, pesticides, persistent organic pollutants such as polychlorinated biphenyls, polybrominated diethyl ethers, and dioxins were emphasized because these chemicals had the greatest depth and breadth of available information. The Statement also included thorough coverage of studies of developmental exposures to EDCs, especially in the fetus and infant, because these are critical life stages during which perturbations of hormones can increase the probability of a disease or dysfunction later in life. A conclusion of the Statement is that publications over the past 5 years have led to a much fuller understanding of the endocrine principles by which EDCs act, including nonmonotonic dose-responses, low-dose effects, and developmental vulnerability. These findings will prove useful to researchers, physicians, and other healthcare providers in translating the science of endocrine disruption to improved public health.

An unusual case of a borderline Brenner tumor associated with bilateral serous cystadenoma and endometrial carcinoma.

Brenner tumor accounts for 1.5 to 2.5% of ovarian tumors. Nearly all are benign and 1% malignant. Less than twenty-five cases of borderline Brenner tumor have been reported worldwide. Our case is the first one related to a bilateral ovarian serous cystadenofibroma and endometrioid adenocarcinoma. This unusual case increases the limited data for borderline Brenner tumors.

Fertility preservation with ovarian stimulation protocols prior to cancer treatment.

An increasing trend towards later childbearing has been reported recently in many developed countries. Although the incidence of reproductive age in women who have delayed pregnancy with cancer is 10%, they may be concerned regarding the preservation of ovarian function due to advanced fertile age and with the impact of cancer treatment on later fertility. Among multiple strategies controlled, ovarian stimulation for embryo or oocyte cryopreservation is currently the most established method for fertility preservation. It is important to choose the appropriate ovulation induction protocol prior to oncologic treatment, because most of these patients have only the chance of a single cycle to conceive. Current treatment protocols offer a minimal time delay until oncologic treatment is commenced. In urgent settings, random-start ovarian stimulation represents a new technique which provides a significant advantage by decreasing the total time of the treatment, because it may be started irrespective of the phase of the cycle without compromising oocyte yield and maturity before cancer treatment. However, in patients with oestrogen-sensitive cancers stimulation, protocols using letrozole are currently preferred over tamoxifen regimens, and therefore, it may be highly advisable to use letrozole with gonadotrophins routinely as a safe, effective and novel protocol of ovulation induction.

Progression of intracranial meningioma during luteinizing hormone-releasing hormone agonist treatment for prostate cancer: case report.

The authors describe a male patient who developed a large intracranial meningioma during the hormone therapy for pre-existing prostate cancer. A 70-year-old man received a brain check-up, and no intracranial abnormality was detected. Five months later, prostate cancer was diagnosed, and he underwent prostatectomy. Leuprorelin acetate, a luteinizing hormone-releasing hormone (LH-RH) agonist, was subsequently administered to the patient once a month for 3 years. After that he presented with a large parasagittal mass, which was excised. The tumor was histologically diagnosed as meningothelial meningioma, and LH-RH receptors were verified immunohistochemically in the cytoplasm of the tumor cells. Leuprorelin acetate may accelerate the rapid growth of meningioma in this patient.

Nomegestrol acetate/estradiol hormonal oral contraceptive and breast cancer risk.

Combined hormonal contraceptives (CHCs) contain estrogen and progestin, which can stimulate estrogen-sensitive and/or progesterone-sensitive breast cancer growth. Until recently, ethinylestradiol had been almost the only estrogen used for decades, and its dose has been greatly reduced over time. The first generations of birth control pills contained approximately five times more estrogen and four times more progestin than the latest contraceptives. Newer CHCs also contain steroids that more closely mimic the physiological estradiol (E2) and progesterone effects. The newer CHC formulations are thus expected to have less influence on the breast, although it is very difficult to demonstrate any difference among the recent available preparations in human studies. Recently, nomegestrol acetate (NOMAC), a neutral, nonandrogenic, progesterone-like profile progestin, has become available in combination with the 'natural' estrogen, E2. According to the literature, NOMAC/E2 is expected to have either a lesser stimulating effect or a neutral effect on estrogen-sensitive breast cancers. We performed an analysis of the available studies and a bibliographical review. The endocrine and metabolic effects of NOMAC/E2 formulation might lead to a lesser breast tissue stimulation. The data reported, confirmed through clinical studies, should be considered when choosing a hormonal contraceptive, especially when breast stimulation is a concern.

Bisphenol A: an endocrine and metabolic disruptor.

Bisphenol A (BPA), initially designed, like diethylstilbestrol, as a synthetic estrogen, has been rapidly and widely used for its cross-linking properties in the manufacture of polycarbonate plastics and epoxy resins. Because of incomplete polymerization and degradation of the polymers by exposure to higher than usual temperatures, BPA leaches out from food and beverage containers, as well as from dental sealants. In humans, free active unconjugated BPA is metabolized by rapid glucurono- or sulfo-conjugation and eliminated via renal clearance. However, exposure to environmental nanomolar concentrations of BPA is ubiquitous and continuous via different routes: oral, air, skin. In rodents, fetal and perinatal exposure to such environmentally relevant doses of BPA has been shown to affect the brain, liver, gut, adipose tissue, endocrine pancreas, mammary gland and reproductive tract and function. Similar concentrations are also able in vitro to impact human malignant breast, prostate, male germ or adipocyte cell lines (with a promoting effect and by interfering with chemotherapy drugs), or to stimulate pancreatic ß cell insulin secretion. High levels of BPA have recently been correlated with obesity, diabetes, cardiovascular diseases, polycystic ovarian disease or low sperm count. However, before the real impact of BPA on human health can be clearly assessed, prospective longitudinal epidemiological studies are needed as well as characterization of selective biomarkers to verify long-term exposure and selective imprinting.

Glyphosate induces human breast cancer cells growth via estrogen receptors.

Glyphosate is an active ingredient of the most widely used herbicide and it is believed to be less toxic than other pesticides. However, several recent studies showed its potential adverse health effects to humans as it may be an endocrine disruptor. This study focuses on the effects of pure glyphosate on estrogen receptors (ERs) mediated transcriptional activity and their expressions. Glyphosate exerted proliferative effects only in human hormone-dependent breast cancer, T47D cells, but not in hormone-independent breast cancer, MDA-MB231 cells, at 10⁻¹² to 10⁻6M in estrogen withdrawal condition. The proliferative concentrations of glyphosate that induced the activation of estrogen response element (ERE) transcription activity were 5-13 fold of control in T47D-KBluc cells and this activation was inhibited by an estrogen antagonist, ICI 182780, indicating that the estrogenic activity of glyphosate was mediated via ERs. Furthermore, glyphosate also altered both ERα and ß expression. These results indicated that low and environmentally relevant concentrations of glyphosate possessed estrogenic activity. Glyphosate-based herbicides are widely used for soybean cultivation, and our results also found that there was an additive estrogenic effect between glyphosate and genistein, a phytoestrogen in soybeans. However, these additive effects of glyphosate contamination in soybeans need further animal study.

[Bisphenol A and hormone-dependent cancers: potential risk and mechanism]. / Bisphénol A et cancers hormono-dépendants - risque potentiel et mécanisme d'action.

Being concerned by the increasing incidence of breast, prostate and testicular cancers, we overviewed the literature on the potential carcinogenic effect of endocrine disruptors (ED). It is extremely difficult to obtain the epidemiological proof of a carcinogenic effect of one ED in human for multi-factorial diseases and the high number of confusing factors. However, many experimental studies in rodents on bis-phenol A (BPA) and its assay in human blood and urine, strongly suggest that BPA might increase the risk of hormone dependant cancers. Contrary to the mitogenic effect of estradiol, directly mediated in mammary cells by the classical nuclear estrogen receptor α, the mechanisms of the deleterious effect of BPA at low doses and in utero remain unknown since the molecular and cellular target(s) have not been defined. Based on all deleterious effects of BPA, France has banned the use of BPA in all food packaging. This should force the food industry to collaborate with members of public research to rapidly find safer substitutes to BPA.

Is polycystic ovary syndrome, a state of relative estrogen excess, a real risk factor for estrogen-dependant malignancies?

Polycystic ovary syndrome (PCOS) is a common endocrinopathy affecting women of fertile age. It is associated with several risk factors and long-term health consequences. Chronic anovulation combined with relative estrogen excess and consequent prolonged stimulatory effect on the endometrium can lead to the pathogenesis of hormonal dependant carcinoma. PCOS is thus traditionally reported to be associated with increased risk of endometrial, as well as breast and ovarian cancers. This article provides a critical literature review of the relationship between PCOS and the incidence of estrogen-dependant gynecological tumours, and it then discusses whether the commonly cited risk factor association can be substantiated by high quality studies which comply with the requirements of "evidence-based medicine."

Membrane-receptor initiated proliferative effects of dienogest in human breast cancer cells.

OBJECTIVES: Dienogest (DNG) is already used in hormone therapy, since recently being also the progestogenic component of the first estradiol based contraceptive pill. Data on breast cancer risk are currently not available. Progesterone receptor membrane component 1 (PGRMC1) is highly expressed in tissues of breast cancer patients and has already been proposed as a predictor for breast cancer risk. METHODS: MCF-7 cells overexpressing PGRMC1 were stimulated with DNG, medroxyprogesterone acetate (MPA), norethisterone (NET) and progesterone (P) as well as sequentially and continuously combined with estradiol (E2). RESULTS: DNG and MPA alone elicited a significant proliferation at 10⁻6 and 10⁻5 M. NET increased cell proliferation at all concentrations tested whereas P showed no effect. E2 alone elicited a significant increase at 10⁻¹° M, no effect was seen at 10⁻¹² M. Addition of the progestins (10⁻6 M) to E2 at 10⁻¹° M had, compared to E2 only, no additional proliferating effect. However, at the low E2 concentration, DNG, MPA and NET significantly increased the E2-stimulated cell proliferation. CONCLUSION: DNG increased proliferation alone and in combination with low E2 concentrations. Thus a progestogen-derived breast cancer risk in the presence of low E2 concentrations cannot be excluded at least in women overexpressing PGRMC1.

Differential mechanisms of action are involved in chlorpyrifos effects in estrogen-dependent or -independent breast cancer cells exposed to low or high concentrations of the pesticide.

It has reported that many environmental compounds may display estrogenic actions and these findings led to researchers to associate breast cancer risk with the use of some pesticides. The aim of this work was to investigate the effect of chlorpyrifos (CPF) on cell proliferation and the ERα-dependence of this action employing MCF-7 and MDA-MB-231 breast cancer cell lines. We have also analyzed CPF action on the cell cycle distribution and the cyclins that are implicated in G1-S and intra-S checkpoints. Finally, the action on cell death and ROS production were studied. We demonstrated the ability of CPF 0.05µM to induce cell proliferation through ERα in hormone-dependent breast cancer cells. In contrast, CPF 50µM induces intra-S arrest modifying checkpoints proteins, through a mechanism that may involve changes in redox balance in MCF-7. In MDA-MB-231, we have found that CPF 50µM produces an arrest in G2/M phase which could be related to the capacity of the pesticide for binding to tubulin sites altering microtubules polymerization. Altogether, our results provide new evidences on the action of the pesticide CPF as an environmental breast cancer risk factor due to the effects that causes on the mechanisms that modulate breast cell proliferation.

The role of the androgen receptor in the development and progression of bladder cancer.

Men are at a higher risk of developing bladder cancer than women. Since bladder cancer cell lines and tissues were found to express the androgen receptor, efforts have been made to inspect whether androgen-mediated androgen receptor signals are implicated in bladder carcinogenesis as well as cancer progression. Mounting evidence supports the view that bladder cancer is a member of the endocrine-related tumors and may clearly explain the gender-specific difference in the incidence. However, the underlying mechanisms of how androgen receptor signals regulate bladder cancer growth are still far from fully characterized. Moreover, it remains controversial whether the androgen receptor pathway always plays a dominant role in bladder cancer progression. In this review, we summarize the available data on the involvement of androgen receptor signaling in bladder cancer. In particular, current evidence demonstrating the stimulatory effects of androgens on tumor progression or, more convincingly, tumorigenesis via the androgen receptor pathway may offer great potential for androgen deprivation as a therapeutic or chemopreventive option in patients with bladder cancer.