Carcinogenetic mechanisms of endocrine disruptors in female cancers (Review)

Interdependency of estradiol-mediated ERα activation and subsequent PR and GREB1 induction to control cell cycle progression

Various groups of chemicals that we encounter in every-day life are known to disrupt the endocrine system, such as estrogen mimics that can disturb normal cellular development and homeostasis. To understand the effect of estrogen on intracellular protein dynamics and how this relates to cell proliferation, we aimed to develop a quantitative description of transcription factor complexes and their regulation of cell cycle progression in response to estrogenic stimulation. We designed a mathematical model that describes the dynamics of three proteins, GREB1, PR and TFF1, that are transcriptionally activated upon binding of 17β-estradiol (E2) to estrogen receptor alpha (ERα). Calibration of this model to imaging data monitoring the expression dynamics of these proteins in MCF7 cells suggests that transcriptional activation of GREB1 and PR depends on the association of the E2-ERα complex with both GREB1 and PR. We subsequently combined this ER signaling model with a previously published cell cycle model and compared this to quantification of cell cycle durations in MCF7 cells following nuclei tracking based on images segmented with deep neural networks. The resulting model predicts the effect of GREB1 and PR knockdown on cell cycle progression, thus providing mechanistic insight in the molecular interactions between ERα-regulated proteins and their relation to cell cycle progression. Our findings form a valuable basis to further investigate the pharmacodynamics of endocrine disrupting chemicals and their influence on cellular behavior.

Additives in Processed Foods as a Potential Source of Endocrine-Disrupting Chemicals: A Review

Processed foods, accounting for most consumable food categories today, contain considerable amounts of food additives. Food additives are substances added to food products to improve taste, consistency, appearance, or shelf life. Various food additives, such as phthalates, bisphenol A, tartrazine, erythrosine, artificial sweeteners, and parabens, have been identified as potential sources of endocrine-disrupting chemicals (EDCs) in processed foods. EDCs are substances that frequently interfere with the regular functioning of the endocrine system, creating an unusual environment in the biological system, which leads to adverse health effects such as the disruption of hormone synthesis, receptor binding, and signal transduction pathways, as well as energy metabolic homeostatic disorders which potentially increasing the risk of obesity, type-2 diabetes, cardiometabolic diseases and may also trigger allergic reactions. Consequently, they can also impact mammary gland development, and reproductive function, further leading to developmental abnormalities. This review aims to insights into the various food additives that act as potential endocrine-disrupting chemicals (EDCs) and to describe their applications in the food industry, as well as the failure of hormonal homeostatic mechanisms, which eventually result in hazardous health effects. It also outlines strategies to reduce the use of food additives and suggests alternative additives with minimal or no endocrine-disrupting properties, highlighting their importance for maintaining human health.

Xenoestrogen concentration in women with endometriosis or leiomyomas: A case-control study

BACKGROUND

Xenoestrogens are synthetic or naturally occurring chemicals capable of altering the endocrine system of humans and animals owing to their molecular similarity to endogenous hormones. There is limited data regarding their effects on women´s health. Chronic exposure to xenoestrogens can promote the development of estrogen-related diseases.

OBJECTIVES

To examine xenoestrogen concentration (TEXB-α) differences between women with leiomyomas or endometriosis and control women, and to study the relationship between the clinical and sociodemographic characteristics of these patients and their xenoestrogen levels.

METHODS

Prospective case-control study. We selected 221 women who underwent surgery at Quironsalud Madrid University Hospital between 2017 and 2021. The cases included 117 patients: 74 women who underwent surgery for uterine leiomyomas, 21 with endometriosis, and 22 with both pathologies. The control group comprised 104 healthy women who underwent surgical procedures for other reasons. TEXB-α was determined in the omental fat of all patients. Using a questionnaire and reviewing the patients' medical records, we collected sociodemographic data and other relevant variables.

RESULTS

A significant majority of study participants (68.8%) had detectable levels of xenoestrogens. We found no association between TEXB-α levels in omental fat and the presence of myomas or endometriosis. In the case group, women living or working in Madrid Community exhibited, on average, 3.12 Eeq pM/g higher levels of TEXB-α compared to those working in other areas (p = 0.030). Women who referred to the use of estrogen-containing hormonal contraceptives had, on average, 3.02 Eeq pM/g higher levels of TEXB-α than those who had never used them (p = 0.022).

CONCLUSIONS

This study found no association between omental xenoestrogen levels and leiomyomas or endometriosis. However, their presence in most participants and their association with highly polluted areas emphasizes the importance of limiting environmental exposure to these substances. We also identified an association between hormonal contraceptive use and xenoestrogen concentration.

Systematic review of the potential carcinogenicity of bisphenol A in humans

Bisphenol A (BPA) is a synthetic chemical to which humans are exposed through a variety of environmental sources. We have conducted a comprehensive, systematic review of 29 epidemiology studies and 27 experimental animal studies, published through May 2022, evaluating the potential carcinogenicity of BPA to contribute to the understanding of whether BPA is carcinogenic in humans. We conducted this review according to best practices for systematic reviews and incorporating established frameworks for study quality evaluation and evidence integration. The epidemiology studies have many limitations that increase the risk of biased results, but overall, the studies do not provide clear and consistent evidence for an association between BPA exposure and the development of any type of cancer. The experimental animal studies also do not provide strong and consistent evidence that BPA is associated with the induction of any malignant tumor type. Some of the proposed mechanisms for BPA carcinogenicity are biologically plausible, but the relevance to human exposures is not clear. We conclude that there is inadequate evidence to support a causal relationship between BPA exposure and human carcinogenicity, based on inadequate evidence in humans, as well as evidence from experimental animal studies that suggests a causal relationship is not likely.

Exposure, toxicological mechanism of endocrine disrupting compounds and future direction of identification using nano-architectonics

Endocrine-disrupting compounds (EDC) are a group of exogenous chemicals that structurally mimic hormones and interfere with the hormonal signaling cascade. EDC interacts with hormone receptors, transcriptional activators, and co-activators, altering the signaling pathway at both genomic and non-genomic levels. Consequently, these compounds are responsible for adverse health ailments such as cancer, reproductive issues, obesity, and cardiovascular and neurological disorders. The persistent nature and increasing incidence of environmental contamination from anthropogenic and industrial effluents have become a global concern, resulting in a movement in both developed and developing countries to identify and estimate the degree of exposure to EDC. The U.S. Environment Protection Agency (EPA) has outlined a series of in vitro and in vivo assays to screen potential endocrine disruptors. However, the multidisciplinary nature and concerns over the widespread application demand alternative and practical techniques for identifying and estimating EDC. The review chronicles the state-of-art 20 years (1990-2023) of scientific literature regarding EDC's exposure and molecular mechanism, highlighting the toxicological effects on the biological system. Alteration in signaling mechanisms by representative endocrine disruptors such as bisphenol A (BPA), diethylstilbestrol (DES), and genistein has been emphasized. We further discuss the currently available assays and techniques for in vitro detection and propose the prominence of designing nano-architectonic-sensor substrates for on-site detection of EDC in the contaminated aqueous environment.

Endocrine-disrupting chemicals and endocrine neoplasia: A forty-year systematic review

INTRODUCTION

Endocrine disrupting chemicals (EDCs) are exogenous substances recognised as relevant tumourigenic chemicals. Studies show that even EDCs which were long abolished are still contributing to the increasing incidence of neoplasia.

AIM

To investigate the association between human exposure to EDCs and the risk of endocrine-related tumours: breast, prostate, thyroid, uterus, testis, and ovary.

METHODS

A systematic review using PubMed, Scopus, and Embase was conducted, searching for original observational studies published between 1980 and 2020, approaching EDCs exposure and endocrine tumourigenic risk in humans. We comprised neoplasia of six endocrine organs. We included all the studies on EDCs reporting tumour odds ratio, risk ratio, or hazard ratio. Study levels of confidence and risk of bias were accessed applying accredited guidelines. Human-made accidents and natural EDCs were not considered in the present study.

RESULTS

Our search returned 3271 papers. After duplicate removal and screening, only 237 papers were included (corresponding to 268 records). EDCs were grouped from the most frequently (pesticides) to the least frequently studied (salts). The most tumourigenic EDC groups were phthalates (63%), heavy metals (54%), particulate matter (47%), and pesticides (46%). Pesticides group comprised the highest number of retrieved studies (n = 133). Increased neoplasia risk was found in 43-67% of the studies, with a lower value for ovary (43%) and a higher value for thyroid (67%).

CONCLUSIONS

The innovative nature of our review comes from including human studies of six endocrine-related neoplasia aiming to understand the contribution of specific EDCs groups to each organ's tumourigenesis. Thyroid was the organ presenting the highest cancer risk after EDC exposure which may explain the increasing thyroid cancer incidence. However, detailed and controlled works reporting the effects of EDCs are scarce, probably justifying conflicting results. Multinational and multicentric human studies with biochemical analysis are needed to achieve stronger and concordant evidence.

Multi- and Transgenerational Effects of Environmental Toxicants on Mammalian Reproduction

Environmental toxicants (ETs) are an exogenous chemical group diffused in the environment that contaminate food, water, air and soil, and through the food chain, they bioaccumulate into the organisms. In mammals, the exposure to ETs can affect both male and female fertility and their reproductive health through complex alterations that impact both gametogeneses, among other processes. In humans, direct exposure to ETs concurs to the declining of fertility, and its transmission across generations has been recently proposed. However, multi- and transgenerational inheritances of ET reprotoxicity have only been demonstrated in animals. Here, we review recent studies performed on laboratory model animals investigating the effects of ETs, such as BPA, phthalates, pesticides and persistent contaminants, on the reproductive system transmitted through generations. This includes multigenerational effects, where exposure to the compounds cannot be excluded, and transgenerational effects in unexposed animals. Additionally, we report on epigenetic mechanisms, such as DNA methylation, histone tails and noncoding RNAs, which may play a mechanistic role in a nongenetic transmission of environmental information exposure through the germline across generations.

A Mixture of Endocrine Disruptors and the Pesticide Roundup® Induce Oxidative Stress in Rabbit Liver When Administered under the Long-Term Low-Dose Regimen: Reinforcing the Notion of Real-Life Risk Simulation

Humans are exposed to xenobiotic mixtures daily through the long-term, low-dose regimen. Investigations designed to simulate this exposure profile approach the real-life risk simulation (RLRS) idea of modern toxicology. The purpose of the present study was to investigate the effects of 12-month exposure of New Zealand rabbits to a xenobiotic mixture comprising seven endocrine disruptors (EDs), which are chemical substances raising great concerns for human health, as well as the herbicide glyphosate, and its commercial formulation Roundup^®, on blood and tissues redox status. It is reported herein that at the systemic level, the administration of the EDs mixture induced perturbations of blood redox homeostasis at 3 months, whereas at 6 and 12 months, it activated redox adaptations. Contrariwise, exposure to glyphosate and Roundup^®, individually, caused mainly disturbances of blood redox equilibrium. At the tissue level, particularly in the liver, the administration of both the EDs mixture and Roundup^® induced oxidative stress, whereas glyphosate did not affect it. The RLRS notion appears to be confirmed through these findings. Indeed, the administration of the EDs mixture and Roundup^®, under the long-term, low-dose regimen, elicited detrimental effects on the redox status of the liver, a crucial tissue with a valuable biological role in the detoxification of organisms from xenobiotics.

The Endocrine Disruptor Compound Bisphenol-A (BPA) Regulates the Intra-Tumoral Immune Microenvironment and Increases Lung Metastasis in an Experimental Model of Breast Cancer

Simple Summary

The widely spread microplastic component and endocrine disruptor BPA is a hazardous material recognized for a long time. Here, for the first time, we demonstrated that BPA, administered into mice in a very specific developmental step of the animal (3 days post-natal), induces an increase in metastasis to the lung in the adult life, compared to the control or vehicle mice. In addition, of novelty, it is the analysis of the cytokine tumor microenvironment, which is the reason for the increased metastasis by BPA (BPA induce the increase in pro-metastatic cytokines).

Abstract

Breast cancer (BC) metastasis represents the main physiopathology leading to poor prognosis and death. Bisphenol A (BPA) is a pollutant, classified as an endocrine-disrupting chemical compound with estrogenic properties, their exposure in the early stages of neonatal life leads to an increase in the size and weight of breast tumors and induces cellular changes in the tumoral immune microenvironment where cytokines play a key role. Thus, we used female BALB/c mice exposed neonatally to a single dose of BPA. Once mice reached sexual maturity, a mammary tumor was induced, injecting 4T1 cells in situ. After 25 days of injection, we evaluated endocrine alterations, cytokine expression, tissue alterations denoted by macro or micro-metastasis in the lung, and cell infiltration induced by metastasis. We found that BPA neonatal treatment did not show significant endocrine alterations. Noteworthy, BPA led to an augmented rate of metastasis to the lung associated with higher intratumoral expression of IL-1β, IL-6, IFN-γ, TNF-α, and VEGF. Our data suggest that cytokines are key players in the induction of BC metastasis and that BPA (an environmental pollutant) should be considered as a risk factor in the clinical history of patients as a possible inductor of BC metastasis.

Diet and food type affect urinary pesticide residue excretion profiles in healthy individuals: results of a randomized controlled dietary intervention trial

BACKGROUND

Observational studies have linked pesticide exposure to various diseases, whereas organic food consumption has been associated with positive health outcomes. Organic farming standards prohibit the use of most pesticides, and organic food consumption may therefore reduce pesticide exposure.

OBJECTIVES

To determine the effects of diet (Western compared with Mediterranean) and food type (conventional compared with organic) and sex on urinary pesticide residue excretion (UPRE), as well as associations between specific diet components and UPRE.

METHODS

In this 2-wk, randomized dietary intervention trial, healthy adults were randomly allocated to an intervention (n = 13) or conventional (n = 14) group. Whereas participants in the intervention group consumed a Mediterranean diet (MedDiet) made entirely from organic foods, the conventional group consumed a MedDiet made entirely from conventional foods. Both groups consumed habitual Western diets made from conventional foods before and after the 2-wk intervention period. The primary outcome was UPRE. In addition, we assessed diet composition and pesticide residue profiles in foods eaten. Participants were aware of group assignment, but the study assessors were not.

RESULTS

During the intervention period, total UPRE was 91% lower with organic (mean 17 μg/d; 95% CI: 15, 19) than with conventional (mean 180 μg/d; 95% CI: 153, 208) food consumption (P < 0.0001). In the conventional group, switching from the habitual Western diet to the MedDiet increased insecticide excretion from 7 to 25 μg/d (P < 0.0001), organophosphate excretion from 5 to 19 μg/d (P < 0.0001), and pyrethroid residue excretion from 2.0 to 4.5 μg/d (P < 0.0001). Small but significant effects of sex were detected for chlormequat, herbicide, and total pesticide residue excretion.

CONCLUSIONS

Changing from a habitual Western diet to a MedDiet was associated with increased insecticide, organophosphate, and pyrethroid exposure, whereas organic food consumption reduced exposure to all groups of synthetic chemical pesticides. This may explain the positive health outcomes linked to organic food consumption in observational studies. This trial was registered at www.clinicaltrials.gov as NCT03254537.

Rodent Model of Gender-Affirming Hormone Therapies as Specific Tool for Identifying Susceptibility and Vulnerability of Transgender People and Future Applications for Risk Assessment

Transgenders (TGs) are individuals with gender identity and behaviour different from the social norms; they often undergo gender-affirming hormone therapy (HT). HT for TG men involves testosterone treatment and, for TG women, oestrogen plus androgen-lowering agents. Due-but not limited-to the lifelong lasting HT, usually TG people experience several physical and behavioural conditions leading to different and specific susceptibility and vulnerability in comparison to general population, including the response to chemical contaminants present in daily life. In particular, the exposure to the widespread endocrine disrupters (EDs) may affect hormonal and metabolic processes, leading to tissue and organ damage. Since the endocrine system of TG people is overstimulated by HT and, often, the targets overlap with ED, it is reasonable to hypothesize that TG health deserves special attention. At present, no specific tools are available to study the toxicological effects of environmental contaminants, including EDs, and the potential long-term consequences of HT on TG people. In this context, the development of adequate and innovative animal models to mimic gender-affirming HT have a high priority, since they can provide robust data for hazard identification in TG women and men, leading to more reliable risk assessment.

A multidisciplinary approach remains the best strategy to improve and strengthen the management of ovarian cancer (Review)

Ovarian cancer represents one of the most aggressive female tumors worldwide. Over the decades, the therapeutic options for the treatment of ovarian cancer have been improved significantly through the advancement of surgical techniques as well as the availability of novel effective drugs able to extend the life expectancy of patients. However, due to its clinical, biological and molecular complexity, ovarian cancer is still considered one of the most difficult tumors to manage. In this context, several studies have highlighted how a multidisciplinary approach to this pathology improves the prognosis and survival of patients with ovarian cancer. On these bases, the aim of the present review is to present recent advantages in the diagnosis, staging and treatment of ovarian cancer highlighting the benefits of a patient‑centered care approach and on the importance of a multidisciplinary team for the management of ovarian cancer.

The Long-Term DEHP Exposure Confers Multidrug Resistance of Triple-Negative Breast Cancer Cells through ABC Transporters and Intracellular ROS

The characteristics of phthalates had been thought to be similar to endocrine disruptors, which increases cancer risk. The role of phthalates in acquired drug resistance remains unclear. In this study, we investigated the effect of di-(2-ethylhexyl) phthalate (DEHP) on acquired drug resistance in breast cancer. MCF7 and MDA-MB-231 breast cancer cells were exposed to long-term physiological concentration of DEHP for more than three months. Long-exposure DEHP permanently attenuated the anti-proliferative effect of doxorubicin with estrogen receptor-independent activity even after withdrawal of DEHP. Long term DEHP exposure significantly reduced ROS (O2-) level in MDA-MB-231 cells while increased in MCF7 cells. ATP-binding cassette (ABC) transporters possess a widely recognized mechanism of drug resistance and are considered a target for drug therapy. Upregulation of ABC family proteins, ABCB-1 and ABCC-1 observed in DEHP-exposed clones compared to doxorubicin-resistant (DoxR) and parental MDA-MB-231 cells. A viability assay showed enhanced multidrug resistance in DEHP-exposed clones against Dox, topotecan, and irinotecan. Inhibition of ABC transporters with tariquidar, enhanced drug cytotoxicity through increased drug accumulation reversing acquired multidrug resistance in MDA-MB-231 breast cancer cells. Tariquidar enhanced Dox cytotoxicity by increasing intracellular ROS production leading to caspase-3 mediated apoptosis. Activation of PI3K/Akt signaling enhanced proliferation and growth of DEHP-exposed MDA-MB-231 cells. Overall, long-term DEHP exposure resulted in acquired multidrug resistance by upregulating ABCB-1 and ABCC1; apart from proliferation PI3K/Akt may be responsible for acquired drug resistance through ABC transporter upregulation. Targeting ABCB1 and ABCC1 with tariquidar may be a promising strategy for reversing the acquired multidrug resistance of triple-negative breast cancer cells.

Endocrine-Disrupting Chemicals and Infectious Diseases: From Endocrine Disruption to Immunosuppression

Endocrine-disrupting chemicals (EDCs) are hormonally active compounds in the environment that interfere with the body's endocrine system and consequently produce adverse health effects. Despite persistent public health concerns, EDCs remain important components of common consumer products, thus representing ubiquitous contaminants to humans. While scientific evidence confirmed their contribution to the severity of Influenza A virus (H1N1) in the animal model, their roles in susceptibility and clinical outcome of the coronavirus disease (COVID-19) cannot be underestimated. Since its emergence in late 2019, clinical reports on COVID-19 have confirmed that severe disease and death occur in persons aged ≥65 years and those with underlying comorbidities. Major comorbidities of COVID-19 include diabetes, obesity, cardiovascular disease, hypertension, cancer, and kidney and liver diseases. Meanwhile, long-term exposure to EDCs contributes significantly to the onset and progression of these comorbid diseases. Besides, EDCs play vital roles in the disruption of the body's immune system. Here, we review the recent literature on the roles of EDCs in comorbidities contributing to COVID-19 mortality, impacts of EDCs on the immune system, and recent articles linking EDCs to COVID-19 risks. We also recommend methodologies that could be adopted to comprehensively study the role of EDCs in COVID-19 risk.

Potential Role of Lycopene in the Inhibition of Di(2-ethylhexyl) Phthalate-Induced Ferroptosis in Spleen Via Modulation of Iron Ion Homeostasis

Di(2-ethylhexyl) phthalate (DEHP) is a synthetic chemical and widely used as a plasticizer. Humans can be exposed to DEHP through direct contact or environmental contamination. Lycopene (Lyc) has been discussed as a potential effector in the prevention and therapy of various diseases. 140 male mice were assigned into control, vehicle control, Lyc (5 mg/kg BW/d), DEHP (500 and 1000 mg/kg BW/d, respectively), and DEHP + Lyc groups and treated with an oral gavage that lasted 28 d. The ultrastructural results showed that DEHP induced pathological changes and mitochondrial injuries. We further revealed that DEHP exposure destroyed the Fe²⁺ imbalance homeostasis and, consequently, increases of lipid peroxidation and inhibition of cysteine/glutamate antiporter, all of which were involved in the process of ferroptsis. Moreover, the supplementation of Lyc significantly inhibited the ferroptsis changes mentioned above. Altogether, these results indicated that DEHP exposure triggered splenic cell death via ferroptosis; meanwhile, they also shed new evidence on a potential clue for the intervention and prevention of DEHP-related diseases.

Exposure to endocrine disruptor alkylphenols and the occurrence of endometrial cancer

Exposure to environmental chemicals with oestrogenic effects has been associated with the development of endometrial cancer (EMCa). EMCa has become the most commonly diagnosed cancer of the female genital tract. To further understand the potential association between exposure to environmental endocrine disruptors and the occurrence of EMCa, we performed a case-control study between 2011 and 2014. We aimed to detect and compare concentrations of a known hormone disruptor, alkylphenol, between women diagnosed with either EMCa or uterine leiomyoma, and those who did not have either of these. Subjects were women diagnosed with either EMCa or uterine leiomyoma (LM) and healthy controls. A structured questionnaire was administered to collect information on lifestyle and health status. Gas chromatography/mass spectrometry was used to measure urinary NP and OP concentrations in participants. Multiple regression analysis was used to examine the association between exposure and outcomes. Overall, 397 women were recruited, including 49 with EMCa, 247 with LM, and 101 controls. Among them, 73.6% showed detectable levels of NP and 61.0% showed detectable levels of OP. The EMCa group had a significantly higher NP concentration than the control group. Higher OP concentrations were also found in participants with EMCa than those with LM and controls. In addition, women in the upper tertile of the NP group had a significantly increased risk of EMCa occurrence (odds ratio [95% confidence interval] = 4.47 [1.69-11.84] for EMCa vs. control). The same was found in the group of women with more than the median level of OP (odds ratio [95% confidence interval] = 4.32 [2.01-9.30] for EMCa vs. LM). Stratification of pre- and post-menopausal groups resulted in a similar association. The results show that NP/OP exposure is associated with EMCa. Further investigations and exposure minimisation are suggested.

A fast-multiclass method for the determination of 21 endocrine disruptors in human urine by using vortex-assisted dispersive liquid-liquid microextraction (VADLLME) and LC-MS/MS

Simplicity, speed, and reduced cost are essential demands for routine analysis in human biomonitoring studies. Moreover, the availability of higher volumes of human specimens is becoming more restrictive due to ethical controls and to the costs associated with sample transportation and storage. Thus, analytical methods requiring much lower sample volumes associated with simultaneous detection capability (multiclass analysis) are with a very high claim. In this sense, the present approach aimed at the development of a method for preconcentration and simultaneous determination of four classes of endocrine disruptors (seven bisphenols, seven parabens, five benzophenones, and two antimicrobials) in the urine. The approach is based on vortex-assisted dispersive liquid-liquid microextraction (VADLLME) and high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). After optimization of the significant parameters of VADLLME extraction, the proposed procedure showed to be simple, fast, sensitive, requiring only 1.0 mL of urine, 400 μL of organic solvents with a total stirring time of 20 s. Moreover, a variation of inter-day and between-day runs were lower than 10.0% and 11.0%, respectively. Finally, the proposed method was successfully applied to the analysis of 50 urine samples of Brazilian pregnant women to establish reference ranges.

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.

Di(2-ethylhexyl) phthalate (DEHP) increases proliferation of epithelial breast cancer cells through progesterone receptor dysregulation

The di(2-ethylhexyl) phthalate (DEHP) is a plasticizer incorporated to plastic matrices of widely used consumer products. However, it is gradually released from these products, resulting in a chronic exposure for humans. Although DEHP, similar to other members of the phthalates family, is generally considered as an endocrine disruptor, the mechanisms implicated in its toxicity are yet poorly understood. Our objective was to determine the effects of an exposure to DEHP and to one of its major metabolite, the mono(2-ethylhexyl) phthalate (MEHP) on markers involved in breast carcinogenesis. T-47D cells were exposed to environmentally relevant and higher doses of DEHP and MEHP (0.1-10 000 nM) for 4 days. Our results showed that an exposure to 10 000 nM of DEHP and 0.1 nM of MEHP significantly increased the proliferation of T-47D cells, without inducing apoptosis. In addition, a significant increase in the protein levels of the isoform A of the progesterone receptor (PR) and of nuclear levels of PR were observed in T-47D cells exposed to 10 000 nM of DEHP. Importantly, the increased proliferation and nuclear levels of PR were totally and partially inhibited, respectively, by Mifepristone, a PR antagonist. These results suggest that an exposure to DEHP or MEHP increase cell proliferation by activating PR signaling, which could potentially increase the risks to develop breast cancer. The mechanism of activation of the progesterone pathway by DEHP and the long-term consequences of this activation remained to be elucidated.

A Linkage Between Thyroid and Breast Cancer: A Common Etiology?

Breast and thyroid cancers are two malignancies with highest incidence in women. These cancers often occur metachronously. Women with thyroid cancer are at increased risk for subsequent breast cancer; women with breast cancer have an increased incidence of later development of thyroid cancer, suggesting a common etiology. This bidirectional relationship is reported worldwide; however, the underlying reasons for this co-occurrence are unknown. In this review, we summarize the current epidemiologic evidence and putative mechanisms of these metachronous or synchronous cancers. Key potential causative factors are chemotherapy and radiotherapy of the primary tumor, genetic variants linking the two diseases, hormonal signaling both from the thyroid gland and from estrogens, and lifestyle and environmental factors. There is a critical need for additional epidemiologic studies focused on gender and regional incidence together with molecular investigations on common tumorigenic pathways in these endocrine cancers. Understanding the putative mechanisms will aid in the diagnosis and clinical management of both diseases.

Di-2-ethylhexylphthalate promotes thyroid cell proliferation and DNA damage through activating thyrotropin-receptor-mediated pathways in vitro and in vivo

Phthalates are being suggested to be associated with altered thyroid function and proliferative changes, but detailed mechanisms remain unclear. Here, we examined the effects of di-(2-ethylhexyl) phthalate (DEHP) on DNA damage and proliferation in thyroid using thyroid carcinoma cell line, 8505C, in vitro and the rats orally treated with DEHP at 0, 0.3, 3, 30 and 150 mg/kg for 90 days from post-natal day 9 in vivo. Exposure to DHEP (1-50 μM) induced cellular proliferation, as evidenced by increased cell viability and DNA synthesis. Activation of γH2AX, a sensitive biomarker for DNA damage was observed following the exposure to DHEP (from 5 to 50 μM) with increased comet tail moment (5-100 μM) in comet assay, reflecting that DNA damage also occurred. When upstream signaling was examined, both thyrotropin receptor (TSHR)-ERK1/2 axis and TSHR-AKT axis were activated with upregulation of Pax8, a master transcriptional factor for thyroid differentiation and proliferation. Thyroid tissue from juvenile rats orally exposed to DEHP also confirmed DNA damage responses and the activation of TSHR signaling, which was evident from 0.3 to 3 mg/kg respectively. Notably, deletion of TSHR through siRNA attenuated these DEHP-induced events in vitro. Collectively these results suggest that DEHP induces DNA damage and cellular proliferation in thyroid, which appears to be from TSHR activation, providing an important insight into endocrine disrupting activities of phthalates on thyroid.

Environmental Carcinogenesis and Transgenerational Transmission of Carcinogenic Risk: From Genetics to Epigenetics

The dominant pathogenic model, somatic mutation theory (SMT), considers carcinogenesis as a ‘genetic accident’ due to the accumulation of ‘stochastic’ DNA mutations. This model was proposed and accepted by the scientific community when cancer mainly affected the elderly, but it does not explain the epidemiological observation of the continuous increase in cancer incidence among children and young adults. Somatic mutation theory has been proposed for a revision based on the emerging experimental evidence, as it does not fully address some issues that have proven to be crucial for carcinogenesis, namely: the inflammatory context of cancer; the key role played by the stroma, microenvironment, endothelial cells, activated macrophages, and surrounding tissues; and the distorted developmental course followed by the neoplastic tissue. Furthermore, SMT is often not able to consider either the existence of specific mutations resulting in a well-defined cancer type, or a clear relationship between mutations and tumor progression. Moreover, it does not explain the mechanism of action of the non-mutagenic and environmental carcinogens. In the last decade, cancer research has highlighted the prominent role of an altered regulation of gene expression, suggesting that cancer should be considered as a result of a polyclonal epigenetic disruption of stem/progenitor cells, mediated by tumour-inducing genes. The maternal and fetal exposure to a wide range of chemicals and environmental contaminants is raising the attention of the scientific community. Indeed, the most powerful procarcinogenic mechanisms of endocrine disruptors and other pollutants is linked to their potential to interfere epigenetically with the embryo-fetal programming of tissues and organs, altering the regulation of the genes involved in the cell cycle, cell proliferation, apoptosis, and other key signaling pathways. The embryo-fetal exposure to environmental, stressful, and proinflammatory triggers (first hit), seems to act as a ‘disease primer’, making fetal cells and tissues more susceptible to the subsequent environmental exposures (second hit), triggering the carcinogenic pathways. Furthermore, even at the molecular level, in carcinogenesis, ‘epigenetics precedes genetics’ as global DNA hypomethylation, and the hypermethylation of tumor suppressor genes are common both in cancerous and in precancerous cells, and generally precede mutations. These epigenetic models may better explain the increase of cancer and chronic/degenerative diseases in the last decades and could be useful to adopt appropriate primary prevention measures, essentially based on the reduction of maternal-fetal and child exposure to several procarcinogenic agents and factors dispersed in the environment and in the food-chains, as recently suggested by the World Health Organization.

Transplacental exposure to environmental carcinogens: Association with childhood cancer risks and the role of modulating factors

Biological responses to carcinogens from environmental exposure during adulthood are modulated over years or decades. Conversely, during transplacental exposure, the effects on the human foetus change within weeks, intertwining with developmental mechanisms: even short periods of transplacental exposure may be imprinted in the organism for a lifetime. The pathways leading to childhood and juvenile cancers, such as leukaemias, neuroblastoma/brain tumours, hepatoblastoma, and Willm's tumour involve prenatally-induced genomic, epigenomic and/or non-genomic effects caused by xenobiotics. Pregnant women most often live in complex environmental settings that cause transplacental exposure of the foetus to xenobiotic mixtures. Mother-child biomonitoring should integrate the analysis of chemicals/radiation present in the living and workplace environment with relevant risk modulators related to life style. The interdisciplinary approach for transplacental cancer risk assessment in high-pressure areas should be based on an integrated model for mother-child exposure estimation via profiling the exposure level by water quality analysis, usage of emission grids, and land use maps.