Evaluation of estrogen receptor alpha activation by glyphosate-based herbicide constituents

Systemically Achievable Doses of Beer Flavonoids Induce Estrogenicity in Human Endometrial Cells and Cause Synergistic Effects With Selected Pesticides

Some prenylated polyphenols originating from hops, which are thus natural constituents of beer, have been discussed critically for their agonistic potential toward estrogen receptors. So far, little attention has been attributed to the fact that humans are typically not exposed to isolated compounds, but to mixtures which for example might comprise in addition to hop flavonoids further xenoestrogens, e.g., certain pesticides used for plant protection of hops and barley. Thus, we used the alkaline phosphatase assay to assess combinatory estrogenic effects of three signature compounds – xanthohumol, 8-prenylnaringenin and iso-xanthohumol–on Ishikawa cells in a combination that resembled the concentration ratios observable in beer. Moreover, we added this natural flavonoid pattern to a mixture of representative estrogenic pesticides to assess their combined effects. Using state-of-the-art statistical tools, we observed cumulative to slightly synergistic effects between isolated flavonoids as well as the flavonoid and the pesticide mixture. Of potential importance, these effects were found at low nanomolar hop polyphenol concentrations that one can reasonably expect to occur in vivo after the consumption of strongly hopped beer. Taken together, our results imply that cumulative/synergistic estrogenicity should be explored in detail and urgently be incorporated into risk assessment of prenylated chalcones.

Intergenerational thyroid hormone homeostasis imbalance in cerebellum of rats perinatally exposed to glyphosate-based herbicide

Agrochemicals became a public health concern due to increased human exposure and possible endocrine disruption effects in several organs, including the brain. Thyroid hormones controls neurodevelopment, which turn them sensitive to endocrine disruptors (EDs). In this work, we evaluated the effect of glyphosate-based herbicides (GBH) as an intergenerational endocrine disrupter on thyroid homeostasis in cerebellar cells. Female pregnant Wistar rats were exposed to Roundup Transorb® solution at 5 and 50 mg/kg/day, from gestation day 18 to post-natal day 5 (P5). Cerebellum of male offspring was used to evaluate gene expression. The mRNA levels of thyroid hormone receptors, hormonal conversion enzymes, hormone transporters, as well as, de novo epigenetic regulators were altered, with some of these genes presenting a non-monotonic dose response. Furthermore, metabolomic profile correlation with tested dose demonstrated altered metabolic profile, in agreement with cerebellar gene alterations. Moreover, cerebellar primary cultures exposed to non-toxic GBH concentration presented a decrease level in glial fibrillary acidic protein, a protein regulated by endocrine signals. In conclusion, our results indicate that animals exposed to non-toxic GBH doses during perinatal phase carry intergenerational alterations in key regulators of cellular thyroid hormone homeostasis and epigenetic controllers in adulthood, indicating the possible ED effect of GBH based on epigenetic alterations.

Epigenetic Changes Associated With Exposure to Glyphosate-Based Herbicides in Mammals

Glyphosate is a phosphonomethyl amino acid derivative present in a number of non-selective and systemic herbicides. During the last years the use of glyphosate-based herbicide (GBH) has been increasing exponentially around the world, including Argentina. This fact added to the detection of glyphosate, and its main metabolite, amino methylphosphonic acid (AMPA), in environmental matrices such as soil, sediments, and food, has generated great concern about its risks for humans, animals, and environment. During the last years, there were controversy and intense debate regarding the toxicological effects of these compounds associated with the endocrine system, cancer, reproduction, and development. The mechanisms of action of GBH and their metabolites are still under investigation, although recent findings have shown that they could comprise epigenetic modifications. These are reversible mechanisms linked to tissue-specific silencing of gene expression, genomic imprinting, and tumor growth. Particularly, glyphosate, GBH, and AMPA have been reported to produce changes in global DNA methylation, methylation of specific genes, histone modification, and differential expression of non-coding RNAs in human cells and rodents. Importantly, the epigenome could be heritable and could lead to disease long after the exposure has ended. This mini-review summarizes the epigenetic changes produced by glyphosate, GBHs, and AMPA in humans and rodents and proposes it as a potential mechanism of action through which these chemical compounds could alter body functions.

Glyphosate and the key characteristics of an endocrine disruptor: A review

Glyphosate is a large-spectrum herbicide that was introduced on the market in 1974. Due to its important impact on the crop industry, it has been significantly diversified and expanded being considered the most successful herbicide in history. Currently, its massive use has led to a wide environmental diffusion and its human consumption through food products has made possible to detect it in urine, serum, and breast milk samples. Nevertheless, recent studies have questioned its safety and international agencies have conflicting opinions about its effects on human health, mainly as an endocrine-disrupting chemical (EDC) and its carcinogenic capacity. Here, we conduct a comprehensive review where we describe the most important findings of the glyphosate effects in the endocrine system and asses the mechanistic evidence to classify it as an EDC. We use as guideline the ten key characteristics (KCs) of EDC proposed in the expert consensus statement published in 2020 (La Merrill et al., 2020) and discuss the scopes of some epidemiological studies for the evaluation of glyphosate as possible EDC. We conclude that glyphosate satisfies at least 8 KCs of an EDC, however, prospective cohort studies are still needed to elucidate the real effects in the human endocrine system.

Controversies on Endocrine and Reproductive Effects of Glyphosate and Glyphosate-Based Herbicides: A Mini-Review

Glyphosate-based herbicides (GBHs) are among the most used pesticides worldwide, presenting high potential for human exposure. Recently, a debate was raised on glyphosate risks to human health due to conflicting views over its potential carcinogenic and endocrine disruptive properties. Results from regulatory guideline studies, reports from Regulatory Agencies, and some literature studies point to a lack of endocrine disrupting properties of the active ingredient glyphosate. On the other hand, many in vivo and in vitro studies, using different experimental model systems, have demonstrated that GBHs can disrupt certain hormonal signaling pathways with impacts on the hypothalamic-pituitary-gonadal axis and other organ systems. Importantly, several studies showed that technical-grade glyphosate is less toxic than formulated GBHs, indicating that the mixture of the active ingredient and formulants can have cumulative effects on endocrine and reproductive endpoints, which requires special attention from Regulatory Agencies. In this mini-review, we discuss the controversies related to endocrine-disrupting properties of technical-grade glyphosate and GBHs emphasizing the reproductive system and its implications for human health.

Estrogen Disrupting Pesticides in Nebraska Groundwater: Trends between Pesticide-contaminated Water and Estrogen-related Cancers in An Ecological Observational Study

Estrogen disrupting pesticides (EDP) are pesticides that modify estrogen activities in estrogen-producing vertebrates. A substantial amount of these pesticides has been detected in human tissues, and they function directly to disrupt estrogen synthesis or effector cells. This study examines EDP’s ecological distribution across Nebraska counties and its association with estrogen-related cancers (ERC). To determine the ecological distribution of selected EDP, county-level choropleth maps were created. Moreover, EDP was tested in separate linear models with different ERC to determine the association between ERC and EDP across Nebraska counties. Exposure data for this county-level study was obtained from the quality assessed agrichemical contaminant Nebraska groundwater database between 1 January 1974 and 31 December 2012. Acetochlor, atrazine, and its metabolites, deethylatrazine (DEA), and de-isopropyl atrazine (DIA) were the most frequently detected EDP in Nebraska groundwater. Moreover, Nebraska county-level potential confounder for ERC such as physically unhealthy days, % adult smoking, % obese adult, % uninsured, and % binge drinking were obtained from County Health Rankings 2010. ERC, which is the outcome variable (breast cancer, uterine cancer, and prostate cancer), were obtained from the Nebraska State profile of the National Cancer Institute. This was expressed as county-level age-standardized incidence cancer rates between 1 January 2013 and 31 December 2017. Data characteristics were determined using percentages, mean, median, 25th and 75th percentile, minimum and maximum values. The relationship between county-level cancer rates and % wells positive for pesticides after adjusting for the county level potential confounders were analyzed in a linear regression model. Water supply wells positive for atrazine and DEA were observed to cluster in the South and South East counties of Nebraska. Furthermore, breast cancer and prostate cancer incidence rates were higher in the southeast of Nebraska with more atrazine and DEA. However, breast cancer and prostate cancer were not significantly associated in a linear regression model with any of the observed EDP. In contrast, uterine cancer was statistically associated with % water supply wells positive for acetochlor (β = 4.01, p = 0.04). While consistent associations were not observed between ERC and EDP from the GIS and the linear regression model, this study’s results can drive future conversation concerning the potential estrogenic effects of acetochlor, atrazine, and its metabolites on the incidence of breast, uterine and prostate cancer in the State of Nebraska.

Autophagy Triggers Tamoxifen Resistance in Human Breast Cancer Cells by Preventing Drug-Induced Lysosomal Damage

Simple Summary

Endocrine therapy with tamoxifen or other endocrine drugs represents the standard treatment for estrogen receptor-positive breast cancer. In spite of effectiveness of this therapy, onset of drug resistance worsens the prognosis of about 30% of patients. Autophagy has recently been proposed as a key player of drug resistance, but the underlying mechanisms are not completely understood. In this research, the authors investigate how autophagy triggers drug resistance in breast cancer cells. The results evidence that tamoxifen affects lysosome integrity, which suggests that this effect may contribute to the anticancer activity of this drug. Activation of autophagy and overexpression of iron-binding proteins synergize in protecting the lysosomal compartment, restraining drug effectiveness in breast cancer cells. According to these results, tamoxifen-resistant cells show an increased autophagic flux and overexpress iron-binding proteins. These findings indicate that screening for the level of iron-binding proteins may help to identify patients at risk for developing drug resistance.

Abstract

Endocrine resistance is a major complication during treatment of estrogen receptor-positive breast cancer. Although autophagy has recently gained increasing consideration among the causative factors, the link between autophagy and endocrine resistance remains elusive. Here, we investigate the autophagy-based mechanisms of tamoxifen resistance in MCF7 cells. Tamoxifen (Tam) triggers autophagy and affects the lysosomal compartment of MCF7 cells, such that activated autophagy supports disposal of tamoxifen-damaged lysosomes by lysophagy. MCF7 cells resistant to 5 µM tamoxifen (MCF7-TamR) have a higher autophagic flux and an enhanced resistance to Tam-induced lysosomal alterations compared to parental cells, which suggests a correlation between the two events. MCF7-TamR cells overexpress messenger RNAs (mRNAs) for metallothionein 2A and ferritin heavy chain, and they are re-sensitized to Tam by inhibition of autophagy. Overexpressing these proteins in parental MCF7 cells protects lysosomes from Tam-induced damage and preserves viability, while inhibiting autophagy abrogates lysosome protection. Consistently, we also demonstrate that other breast cancer cells that overexpress selected mRNAs encoding iron-binding proteins are less sensitive to Tam-induced lysosomal damage when autophagy is activated. Collectively, our data demonstrate that autophagy triggers Tam resistance in breast cancer cells by favoring the lysosomal relocation of overexpressed factors that restrain tamoxifen-induced lysosomal damage.

Are glyphosate and glyphosate-based herbicides endocrine disruptors that alter female fertility?

Numerous evidences have alerted on the toxic effects of the exposure to glyphosate on living organisms. Glyphosate is the herbicide most used in crops such as maize and soybean worldwide, which implies that several non-target species are at a high risk of exposure. Although the Environmental Protection Agency (EPA-USA) has reaffirmed that glyphosate is safe for users, there are controversial studies that question this statement. Some of the reported effects are due to exposure to high doses; however, recent evidences have shown that exposure to low doses could also alter the development of the female reproductive tract, with consequences on fertility. Different animal models of exposure to glyphosate or glyphosate-based herbicides (GBHs) have shown that the effects on the female reproductive tract may be related to the potential and/or mechanisms of actions of an endocrine-disrupting compound. Studies have also demonstrated that the exposure to GBHs alters the development and differentiation of ovarian follicles and uterus, affecting fertility when animals are exposed before puberty. In addition, exposure to GBHs during gestation could alter the development of the offspring (F1 and F2). The main mechanism described associated with the endocrine-disrupting effect of GBHs is the modulation of estrogen receptors and molecules involved in the estrogenic pathways. This review summarizes the endocrine-disrupting effects of exposure to glyphosate and GBHs at low or "environmentally relevant" doses in the female reproductive tissues. Data suggesting that, at low doses, GBHs may have adverse effects on the female reproductive tract fertility are discussed.

The impact and toxicity of glyphosate and glyphosate-based herbicides on health and immunity

Glyphosate, or N-phosphomethyl(glycine), is an organophosphorus compound and a competitive inhibitor of the shikimate pathway that allows aromatic amino acid biosynthesis in plants and microorganisms. Its utilization in broad-spectrum herbicides, such as RoundUp®, has continued to increase since 1974; glyphosate, as well as its primary metabolite aminomethylphosphonic acid, is measured in soils, water, plants, animals and food. In humans, glyphosate is detected in blood and urine, especially in exposed workers, and is excreted within a few days. It has long been regarded as harmless in animals, but growing literature has reported health risks associated with glyphosate and glyphosate-based herbicides. In 2017, the International Agency for Research on Cancer (IARC) classified glyphosate as "probably carcinogenic" in humans. However, other national agencies did not tighten their glyphosate restrictions and even prolonged authorizations of its use. There are also discrepancies between countries' authorized levels, demonstrating an absence of a clear consensus on glyphosate to date. This review details the effects of glyphosate and glyphosate-based herbicides on fish and mammal health, focusing on the immune system. Increasing evidence shows that glyphosate and glyphosate-based herbicides exhibit cytotoxic and genotoxic effects, increase oxidative stress, disrupt the estrogen pathway, impair some cerebral functions, and allegedly correlate with some cancers. Glyphosate effects on the immune system appear to alter the complement cascade, phagocytic function, and lymphocyte responses, and increase the production of pro-inflammatory cytokines in fish. In mammals, including humans, glyphosate mainly has cytotoxic and genotoxic effects, causes inflammation, and affects lymphocyte functions and the interactions between microorganisms and the immune system. Importantly, even as many outcomes are still being debated, evidence points to a need for more studies to better decipher the risks from glyphosate and better regulation of its global utilization.

Bisphenols and Risk of Breast Cancer: A Narrative Review of the Impact of Diet and Bioactive Food Components

Data from preclinical studies suggest a link between increased risk of breast cancer and exposure to bisphenols at doses below what the United States Food and Drug Administration (FDA) considers as safe for consumption. Bisphenols exert estrogenic effects and are found in canned and plastic wrapped foods, food packaging, and plasticware. Mechanistically, bisphenols bind to the estrogen receptor (ER) and activate the expression of genes associated with cell proliferation and breast cancer. In this paper, we present a narrative literature review addressing bisphenol A and chemical analogs including bisphenol AF, bisphenol F, and bisphenol S selected as prototype xenoestrogens; then, we discuss biological mechanisms of action of these bisphenols in breast cells and potential impact of exposure at different stages of development (i.e., perinatal, peripubertal, and adult). Finally, we summarize studies detailing interactions, both preventative and promoting, of bisphenols with food components on breast cancer risk. We conclude the review with a discussion of current controversies in interpretation of the above research and future areas for investigation, including the impact of bisphenols and food components on breast tumor risk.

Cytotoxicity and hormonal activity of glyphosate-based herbicides

Glyphosate-based herbicides (GBHs) are the most widely used pesticides for weed control. In parallel with the renewal of the active ingredient, polyethoxylated POE(15) containing GBHs were banned in the EU in 2016. Since then, co-formulants were changed and numerous GBHs are marketed with different excipients declared as inert substances. In our study, we focused to determine acute and chronic cytotoxicity (by Aliivibrio fischeri assay) and direct hormonal activity (estrogenic and androgenic effects measured by Saccharomyces cerevisiae BLYES/BLYAS strains, respectively) of glyphosate, AMPA, polyethoxylated POE(15) and 13 GBHs from which 11 formulations do not contain polyethoxylated POE(15). Among the pure substances, neither glyphosate nor AMPA had any effects, while polyethoxylated POE(15) exhibited pronounced toxicity and was also estrogenic but not androgenic. Regarding the acute and chronic cytotoxicity and hormonal activity of GBHs, dilution percentages calculated from EC50 values were in the most cases by one or two order of magnitude lower than the minimum recommended dilution for agricultural and household use. Relation could not be observed between the biological effects and type of glyphosate-salts; hence toxicity could be linked to the co-formulants, which are not even declared in 3 GBHs. Toxicological evaluation must focus on these substances and free accessibility of GBHs should be reconsidered.

Neonatal exposure to a glyphosate-based herbicide alters the uterine differentiation of prepubertal ewe lambs

The exposure to endocrine-disrupting compounds (EDCs), such as glyphosate-based herbicides (GBHs), during early life might alter female fertility. The aim of the present study was to evaluate the effects of neonatal exposure to a GBH on sheep uterine development. To achieve this, Friesian ewe lambs were exposed to GBH (2 mg/kg of body weight/day; n = 12) or vehicle (controls; n = 10) through s.c. injections, from postnatal day (PND) 1 to PND14; on PND45, the uteri were obtained to evaluate histomorphological and molecular parameters. Morphological parameters were determined by picrosirius-hematoxylin staining. Protein expression of Ki67 (as a cell proliferation marker), p27, and molecules involved in uterine organogenetic differentiation was measured by immunohistochemistry. We also determined the mRNA expression of the IGF molecular pathway by RT-PCR. Although histomorphology was not modified, the uteri of GBH-exposed ewe lambs showed lower cell proliferation, together with higher p27 protein expression. In addition, the uteri of GBH-exposed ewe lambs showed increased gene expression of insulin-like growth factor binding protein 3 (IGFBP-3), decreased expression of ERα in the luminal (LE) and glandular (GE) epithelia and in the subepithelial stroma (SS), and lower PR expression in the LE but higher in the GE and SS. In addition, GBH treatment decreased the uterine expression of Wnt5a in the GE, of Wnt7a in the SS, of β-catenin in the LE and GE, of Hoxa10 in the SS, and of Foxa2 in the GE as compared with controls. In conclusion, neonatal exposure to GBH decreased cell proliferation and altered the expression of molecules that control proliferation and development in the uterus. All these changes might have adverse consequences on uterine differentiation and functionality, affecting the female reproductive health of sheep. GBH may be responsible for uterine subfertility, acting as an EDC.

Ovarian mitochondrial and oxidative stress proteins are altered by glyphosate exposure in mice

Glyphosate (GLY) usage for weed control is extensive. To investigate ovarian impacts of chronic GLY exposure, female C57BL6 mice were orally administered saline as vehicle control (CT) or GLY at 0.25 (G0.25), 0.5 (G0.5), 1.0 (G1.0), 1.5 (G1.5), or 2 (G2.0) mg/kg for five days per wk. for 20 wks. Feed intake increased (P < .05) in G1.5 and G2.0 mice and body weight increased (P < .05) in G1.0 mice. There was no impact of GLY on estrous cyclicity, nor did GLY affect circulating levels of 17β-estradiol or progesterone. Exposure to GLY did not impact heart, liver, spleen, kidney or uterus weight. Both ovarian weight and follicle number were increased (P < .05) by G2.0 but not affected at lower GLY concentrations. There were no detectable effects of GLY on ovarian protein abundance of pAKT, AKT, pAKT:AKT, γH2AX, STAR, CYP11A1, HSD3B, CYP19A, ERA or ERB. Increased (P < .05) abundance of ATM protein was observed at G0.25 but not higher GLY doses. A dose-dependent effect (P < .10) of GLY exposure on ovarian protein abundance as quantified by LC-MS/MS was observed (G0.25-4 increased, 19 decreased; G0.5-5 increased, 25 decreased; G1.0-65 increased, 7 decreased; G1.5-145 increased, 2 decreased; G2.0-159 increased, 4 decreased). Pathway analysis was performed using DAVID and identified glutathione metabolism, metabolic and proteasome pathways as GLY exposure targets. These data indicate that chronic low-level exposure to GLY alters the ovarian proteome and may ultimately impact ovarian function.

Perinatal exposure to glyphosate or a glyphosate-based formulation disrupts hormonal and uterine milieu during the receptive state in rats

We investigated the effects of perinatal exposure to a glyphosate-based herbicide (GBH) or glyphosate alone (Gly) on female fertility and the hormonal and uterine milieu during the preimplantation period. F0 pregnant rats orally received a GBH or Gly in a dose of 2 mg of glyphosate/kg/day from gestational day (GD) 9 until weaning. F1 females were evaluated to determine the reproductive performance on GD19; and the sex steroid serum levels, the expression of estrogen receptor alpha (ERα), progesterone receptor (PR) and implantation-related genes on GD5 (preimplantation period). GBH and Gly induced preimplantation losses in F1 rats. GBH and Gly groups exhibited higher 17β-estradiol serum levels, without changes in progesterone. Both compounds increased the uterine ERα protein expression, with no differences at transcript level; and only Gly decreased PR mRNA expression. Also, GBH and Gly downregulated Hoxa10 and Lif genes, with no difference in Muc1 and Areg expression. To conclude, perinatal exposure to a GBH or Gly disrupted critical hormonal and uterine molecular targets during the receptive state, possibly associated with the implantation failures. Overall, similar results were found in GBH- and Gly-exposed rats, suggesting that the active principle might be the main responsible for the deleterious effects.

Review and analysis of the potential for glyphosate to interact with the estrogen, androgen and thyroid pathways

Glyphosate was recently evaluated for its potential to interact with the estrogen, androgen and thyroid (EAT) hormone pathways, including steroidogenesis, under the United States Environmental Protection Agency's (USEPA) Endocrine Disruptor Screening Program (EDSP), then by Germany, the rapporteur Member State who led the European Annex 1 renewal for glyphosate, and then by the European Food Protection Agency (EFSA) also as part of the Annex 1 renewal for glyphosate. Under the EDSP, 11 Tier 1 assays were run following the USEPA's validated 890-series test guidelines and included five in vitro and six in vivo assays to evaluate the EAT pathways. Steroidogenesis was evaluated as part of the estrogen and androgen pathways. An up-to-date critical review has been conducted that considered results from the EDSP Tier 1 battery, guideline regulatory studies and an in-depth analysis of the literature studies that informed an endocrine assessment. A strength of this evaluation was that it included data across multiple levels of biological organization, and mammalian and nonmammalian test systems. There was strong agreement across the in vitro and in vivo Tier 1 battery, guideline studies and relevant literature studies, demonstrating that glyphosate does not interact with EAT pathways including steroidogenesis. Based on an analysis of the comprehensive toxicology database for glyphosate and the literature, this review has concluded that glyphosate does not have endocrine-disrupting properties through estrogen, androgen, thyroid and steroidogenic modes of action. © 2020 Society of Chemical Industry.

Quizalofop-p-Ethyl Induces Adipogenesis in 3T3-L1 Adipocytes

Exposure to endocrine disrupting chemicals is an established risk factor for obesity. The most commonly used pesticide active ingredients have never been tested in an adipogenesis assay. We tested for the first time the potential of glyphosate, 2, 4-dichlorophenoxyacetic acid, dicamba, mesotrione, isoxaflutole, and quizalofop-p-ethyl (QpE) to induce lipid accumulation in murine 3T3-L1 adipocytes. Only QpE caused a dose-dependent statistically significant triglyceride accumulation from a concentration of 5 up to 100 µM. The QpE commercial formulation Targa Super was 100 times more cytotoxic than QpE alone. Neither the estrogen receptor antagonist ICI 182, 780 nor the glucocorticoid receptor antagonist RU486 was able to block the QpE-induced lipid accumulation. RNAseq analysis of 3T3-L1 adipocytes exposed to QpE suggests that this compound exerts its lipid accumulation effects via a peroxisome proliferator-activated receptor gamma (PPARγ)-mediated pathway, a nuclear receptor whose modulation influences lipid metabolism. QpE was further shown to be active in a PPARγ reporter gene assay at 100 µM, reaching 4% of the maximal response produced by rosiglitazone, which acts as a positive control. This indicates that lipid accumulation induced by QpE is only in part caused by PPARγ activation. The lipid accumulation capability of QpE we observe suggest that this pesticide, whose use is likely to increase in coming years may have a hitherto unsuspected obesogenic property.

Molecular Basis for Endocrine Disruption by Pesticides Targeting Aromatase and Estrogen Receptor

The intensive use of pesticides has led to their increasing presence in water, soil, and agricultural products. Mounting evidence indicates that some pesticides may be endocrine disrupting chemicals (EDCs), being therefore harmful for the human health and the environment. In this study, three pesticides, glyphosate, thiacloprid, and imidacloprid, were tested for their ability to interfere with estrogen biosynthesis and/or signaling, to evaluate their potential action as EDCs. Among the tested compounds, only glyphosate inhibited aromatase activity (up to 30%) via a non-competitive inhibition or a mixed inhibition mechanism depending on the concentration applied. Then, the ability of the three pesticides to induce an estrogenic activity was tested in MELN cells. When compared to 17β-estradiol, thiacloprid and imidacloprid induced an estrogenic activity at the highest concentrations tested with a relative potency of 5.4 × 10⁻¹⁰ and 3.7 × 10⁻⁹, respectively. Molecular dynamics and docking simulations predicted the potential binding sites and the binding mode of the three pesticides on the structure of the two key targets, providing a rational for their mechanism as EDCs. The results demonstrate that the three pesticides are potential EDCs as glyphosate acts as an aromatase inhibitor, whereas imidacloprid and thiacloprid can interfere with estrogen induced signaling.

Glyphosate induces epithelial mesenchymal transition-related changes in human endometrial Ishikawa cells via estrogen receptor pathway

Glyphosate based herbicides are the most commonly used herbicide in the world. We aimed to determine whether glyphosate (Gly) induces epithelial mesenchymal transition (EMT) - related changes in a human endometrial carcinoma cell line (Ishikawa cells), and whether the estrogen receptor (ER) pathway is involved in these changes. Ishikawa cells were exposed to Gly (0.2 μM and 2 μM) or 17β-estradiol (E2: 10-9 M). We detected that Gly increased cell migration and invasion ability compared to vehicle, as did E2. Moreover, a down regulation of E-cadherin mRNA expression was determined in response to Gly, similar to E2-effects. These results show that Gly promotes EMT-related changes in Ishikawa cells. When an ER antagonist (Fulvestrant: 10-7 M) was co-administrated with Gly, all changes were reversed, suggesting that Gly might promote EMT-related changes via ER-dependent pathway. Our results are interesting evidences of Gly effects on endometrial cancer progression via the ER-dependent pathway.

Agrochemicals and neurogenesis

Agrochemicals or pesticides are compounds widely used to prevent, destroy or mitigate pests such as insects, rodents, herbs and weeds. However, most of them also act as environmental estrogens, anti-estrogens and/or antiandrogenic chemicals. In addition, both herbicides (such as glyphosate and paraquat) and insecticides (such as pyrethroids, organophosphates, neonicotinoids and rotenone) have been shown to exert significant adverse effects on hippocampal neurogenesis. These effects are particularly important because neurogenesis dysregulation could be associated with cognitive decline and neuropathologies such as Alzheimer's disease. This review focuses on the most commonly used agrochemicals in Argentina and their effects on the hippocampal neurogenesis of mammals. It also discusses the disruption of hormone synthesis and action as a possible mechanism through which these chemical compounds could alter the brain functions. Finally, we propose some lines of research to study the potential endocrine mechanisms involved in the effects of agrochemicals on human health and biodiversity.

Glyphosate Induces Metaphase II Oocyte Deterioration and Embryo Damage by Zinc Depletion and Overproduction of Reactive Oxygen Species

Glyphosate is the most popular herbicide used in modern agriculture, and its use has been increasing substantially since its introduction. Accordingly, glyphosate exposure from food and water, the environment, and accidental and occupational venues has also increased. Recent studies have demonstrated a relationship between glyphosate exposure and a number of disorders such as cancer, immune and metabolic disorders, endocrine disruption, imbalance of intestinal flora, cardiovascular disease, and infertility; these results have given glyphosate a considerable amount of media and scientific attention. Notably, glyphosate is a powerful metal chelator, which could help explain some of its effects. Recently, our findings on 2,3-dimercapto-1-propanesulfonic acid, another metal chelator, showed deterioration of oocyte quality. Here, to generalize, we investigated the effects of glyphosate (0 - 300 μM) on metaphase II mouse oocyte quality and embryo damage to obtain insight on its mechanisms of cellular action and the tolerance of oocytes and embryos towards this chemical. Our work shows for the first time that glyphosate exposure impairs metaphase II mouse oocyte quality via two mechanisms: 1) disruption of the microtubule organizing center and chromosomes such as anomalous pericentrin formation, spindle fiber destruction and disappearance, and defective chromosomal alignment and 2) substantial depletion of intracellular zinc bioavailability and enhancement of reactive oxygen species accumulation. Similar effects were found in embryos. These results may help clarify the effects of glyphosate exposure on female fertility and provide counseling and preventative steps for excessive glyphosate intake and resulting oxidative stress and reduced zinc bioavailability.

Exposure to a Glyphosate-based Herbicide Alters the Expression of Key Regulators of Mammary Gland Development on Pre-pubertal Male Rats

We previously reported that exposure during gestation and lactation to a low dose of glyphosate-based herbicide (GBH) reduced the area and perimeter of male offspring mammary gland at postnatal day 60 (PND60), whereas a higher dose increased the longitudinal growth of the gland. Here, our aim was to assess whether perinatal exposure to GBH exhibits endocrine disruptive action in male mammary gland at an early time point (pre-puberty), which could be related to the changes observed after puberty. We also wanted to explore whether an early evaluation of the male rat mammary gland is appropriate to assess exposure to potential endocrine disrupting chemicals (EDCs). Pregnant rats were orally exposed, through the diet, to vehicle (saline solution), 3.5 or 350 mg/kg/day of GBH from gestational day 9 until weaning. At PND21, the male offspring were euthanized, and mammary gland samples were collected. The histology and proliferation index of the mammary glands were evaluated, and the mRNA expression of estrogen (ESR1) and androgen (AR) receptors, cyclin D1 (Ccnd1), amphiregulin (Areg), insulin-like growth factor 1 (IGF1), epidermal growth factor receptor (EGFR) and IGF1 receptor (IGF1R) were assessed. Moreover, the phosphorylated-Erk1/2 (p-ERK1/2) protein expression was determined. No differences were observed in mammary epithelial structures and AR expression between experimental groups; however, the proliferation index was reduced in GBH3.5-exposed males. This result was associated with decreased ESR1, Ccnd1, Areg, IGF1, EGFR and IGF1R mRNA expressions, as well as reduced p-Erk1/2 protein expression in these animals. ESR1, Ccnd1, IGF1R and EGFR expressions were also reduced in GBH350-exposed males. In conclusion, the mammary gland development of pre-pubertal male rats is affected by perinatal exposure to GBH. Although further studies are still needed to understand the molecular mechanisms involved in GBH350 exposure, the present results may explain the alterations observed in mammary gland growth of post-pubertal males exposed to low doses of GBH. Our results also suggest that early evaluation of the male rat mammary gland is useful in assessing exposure to potential EDCs. However, analysis of EDCs effects at later time points should not be excluded.

Relationship between agrochemical compounds and mammary gland development and breast cancer

The exposure to agrochemical pesticides has been associated with several chronic diseases, including different types of cancer and reproductive disorders. In addition, because agrochemical pesticides may act as endocrine disrupting chemicals (EDCs) during different windows of susceptibility, they can increase the risk of impairing the normal development of the mammary gland and/or of developing mammary lesions. Therefore, the aim of this review is to summarize how exposure to different agrochemical pesticides suspected of being EDCs can interfere with the normal development of the mammary gland and the possible association with breast cancer. It has been shown that the mammary glands of male and female rats and mice are susceptible to exposure to non-organochlorine (vinclozolin, atrazine, glyphosate, chlorpyrifos) and organochlorine (endosulfan, methoxychlor, hexachlorobenzene) pesticides. Some of the effects of these compounds in experimental models include increased or decreased mammary development, impaired cell proliferation and steroid receptor expression and signaling, increased malignant cellular transformation and tumor development and angiogenesis. Contradictory findings have been found as to whether there is a causal link between the exposure or the pesticide body burden and breast cancer in humans. However, an association has been observed between pesticides (especially organochlorine compounds) and specific subtypes of breast cancer. Further studies are needed in both humans and experimental models to understand how agrochemical pesticides can induce or promote changes in the development, differentiation and/or malignant transformation of the mammary gland.

Integrated Approach to Evaluate the Association between Exposure to Pesticides and Idiopathic Premature Thelarche in Girls: The PEACH Project

Several pesticides are recognized as endocrine-disrupting chemicals (EDCs) since they can interfere with the dysregulation of sexual, thyroid and neuro-endocrine hormones. Children are particularly vulnerable to the adverse effects of EDCs due to their developmental stage, peculiar lifestyle and dietary habits. In this context, the exposure to pesticides represents an important risk factor associated with early development. This study deals with the possible association between exposure to pesticides and idiopathic premature thelarche in girls from areas of intensive agriculture practice in the Centre of Italy. An integrated approach was set up, including: (i) a case-control study on girls with idiopathic premature thelarche; (ii) the evaluation of multiple pesticides exposure in girls; (iii) the evaluation of multiple pesticides in food; (iv) the dietary intake of pesticide residues; (v) the assessment of toxicological effects of widely used pesticides by in vitro model. Data integration will provide an estimate of the predictive risk of potential effects on girls' health, linked to dietary intake.

Effects of glyphosate exposure on human health: Insights from epidemiological and in vitro studies

Glyphosate (GLY) is a broad-spectrum, post-emergent, non-selective and synthetic universal herbicide, whose commercial formulations are referred to as glyphosate-based-herbicides (GBHs). These chemicals and their metabolites can be found in soil, air, water, as well as groundwater and food products. This review summarizes to summarize current in vitro and epidemiological studies investigating the effects of GLY exposure on human health. Recent human cell studies have reported several GLY and GBH toxicological effects and have contributed to a better understanding of the deleterious consequences associated with their exposure. However, these detrimental effects are dependent on the cell type, chemical composition, as well as magnitude and time of exposure, among other factors. Moreover, the deleterious effects of GLY exposure on human health were observed in epidemiological studies; however, most of these studies have not determined the GLY dosage to confirm a direct effect. While GLY toxicity is clear in human cells, epidemiological studies investigating individuals exposed to different levels of GLY have reported contradictory data. Therefore, based on currently available in vitro and epidemiological data, it is not possible to confirm the complete safety of GLY use, which will require additional comprehensive studies in animal models and humans.

Neuroendocrine Changes in Cholangiocarcinoma Growth

Cholangiocarcinoma (CCA) is a highly aggressive malignancy that emerges from the biliary tree. There are three major classes of CCA-intrahepatic, hilar (perihilar), or distal (extrahepatic)-according to the location of tumor development. Although CCA tumors are mainly derived from biliary epithelia (i.e., cholangiocytes), CCA can be originated from other cells, such as hepatic progenitor cells and hepatocytes. This heterogeneity of CCA may be responsible for poor survival rates of patients, limited effects of chemotherapy and radiotherapy, and the lack of treatment options and novel therapies. Previous studies have identified a number of neuroendocrine mediators, such as hormones, neuropeptides, and neurotransmitters, as well as corresponding receptors. The mediator/receptor signaling pathways play a vital role in cholangiocyte proliferation, as well as CCA progression and metastases. Agonists or antagonists for candidate pathways may lead to the development of novel therapies for CCA patients. However, effects of mediators may differ between healthy or cancerous cholangiocytes, or between different subtypes of receptors. This review summarizes current understandings of neuroendocrine mediators and their functional roles in CCA.

A comprehensive analysis of the animal carcinogenicity data for glyphosate from chronic exposure rodent carcinogenicity studies

Since the introduction of glyphosate-tolerant genetically-modified plants, the global use of glyphosate has increased dramatically making it the most widely used pesticide on the planet. There is considerable controversy concerning the carcinogenicity of glyphosate with scientists and regulatory authorities involved in the review of glyphosate having markedly different opinions. One key aspect of these opinions is the degree to which glyphosate causes cancer in laboratory animals after lifetime exposure. In this review, twenty-one chronic exposure animal carcinogenicity studies of glyphosate are identified from regulatory documents and reviews; 13 studies are of sufficient quality and detail to be reanalyzed in this review using trend tests, historical control tests and pooled analyses. The analyses identify 37 significant tumor findings in these studies and demonstrate consistency across studies in the same sex/species/strain for many of these tumors. Considering analyses of the individual studies, the consistency of the data across studies, the pooled analyses, the historical control data, non-neoplastic lesions, mechanistic evidence and the associated scientific literature, the tumor increases seen in this review are categorized as to the strength of the evidence that glyphosate causes these cancers. The strongest evidence shows that glyphosate causes hemangiosarcomas, kidney tumors and malignant lymphomas in male CD-1 mice, hemangiomas and malignant lymphomas in female CD-1 mice, hemangiomas in female Swiss albino mice, kidney adenomas, liver adenomas, skin keratoacanthomas and skin basal cell tumors in male Sprague-Dawley rats, adrenal cortical carcinomas in female Sprague-Dawley rats and hepatocellular adenomas and skin keratocanthomas in male Wistar rats.

Glyphosate-based herbicide induces hyperplastic ducts in the mammary gland of aging Wistar rats

Glyphosate-based herbicide (GBH) exposure is known to have adverse effects on endocrine-related tissues. Here, we aimed to determine whether early postnatal exposure to a GBH induces long-term effects on the rat mammary gland. Thus, female Wistar pups were injected with saline solution (Control) or GBH (2 mg glyphosate/kg/day) on postnatal days (PND) 1, 3, 5 and 7. At 20 months of age, mammary gland samples were collected to determine histomorphological features, proliferation index and the expression of steroid hormone receptors expression, by immunohistochemistry, and serum samples were collected to assess 17β-estradiol (E2) and progesterone (P4) levels. GBH exposure induced morphological changes evidenced by a higher percentage of hyperplastic ducts and a fibroblastic-like stroma in the mammary gland. GBH-treated rats also showed a high expression of steroid hormone receptors in hyperplastic ducts. The results indicate that early postnatal exposure to GBH induces long-term alterations in the mammary gland morphology of aging female rats.

First evaluation of novel potential synergistic effects of glyphosate and arsenic mixture on Rhinella arenarum (Anura: Bufonidae) tadpoles

The toxicity of glyphosate-based herbicide (GBH) and arsenite (As(III)) as individual toxicants and in mixture (50:50 v/v, GBH-As(III)) was determined in Rhinella arenarum tadpoles during acute (48 h) and chronic assays (22 days). In both types of assays, the levels of enzymatic activity [Acetylcholinesterase (AChE), Carboxylesterase (CbE), and Glutathione S-transferase (GST)] and the levels of thyroid hormones (triiodothyronine; T3 and thyroxine; T4) were examined. Additionally, the mitotic index (MI) of red blood cells (RBCs) and DNA damage index were calculated for the chronic assay. The results showed that the LC50 values at 48 h were 45.95 mg/L for GBH, 37.32 mg/L for As(III), and 30.31 mg/L for GBH-As(III) (with similar NOEC = 10 mg/L and LOEC = 20 mg/L between the three treatments). In the acute assay, Marking's additive index (S = 2.72) indicated synergistic toxicity for GBH-As(III). In larvae treated with GBH and As(III) at the NOEC-48h (10 mg/L), AChE activity increased by 36.25% and 33.05% respectively, CbE activity increased by 22.25% and 39.05 % respectively, and GST activity increased by 46.75% with the individual treatment with GBH and by 131.65 % with the GBH-As(III) mixture. Larvae exposed to the GBH-As(III) mixture also showed increased levels of T4 (25.67 %). In the chronic assay at NOEC-48h/8 (1.25 mg/L), As(III) and GBH-As(III) inhibited AChE activity (by 39.46 % and 35.65%, respectively), but did not alter CbE activity. In addition, As(III) highly increased (93.7 %) GST activity. GBH-As(III) increased T3 (97.34%) and T4 (540.93%) levels. Finally, GBH-As(III) increased the MI of RBCs and DNA damage. This study demonstrated strong synergistic toxicity of the GBH-As(III) mixture, negatively altering antioxidant systems and thyroid hormone levels, with consequences on RBC proliferation and DNA damage in treated R. arenarum tadpoles.

Glyphosate Primes Mammary Cells for Tumorigenesis by Reprogramming the Epigenome in a TET3-Dependent Manner

The acknowledgment that pollutants might influence the epigenome raises serious concerns regarding their long-term impact on the development of chronic diseases. The herbicide glyphosate has been scrutinized for an impact on cancer incidence, but reports demonstrate the difficulty of linking estimates of exposure and response analysis. An approach to better apprehend a potential risk impact for cancer is to follow a synergistic approach, as cancer rarely occurs in response to one risk factor. The known influence of glyphosate on estrogen-regulated pathway makes it a logical target of investigation in breast cancer research. We have used nonneoplastic MCF10A cells in a repeated glyphosate exposure pattern over 21 days. Glyphosate triggered a significant reduction in DNA methylation, as shown by the level of 5-methylcytosine DNA; however, in contrast to strong demethylating agent and cancer promoter UP peptide, glyphosate-treated cells did not lead to tumor development. Whereas UP acts through a DNMT1/PCNA/UHRF1 pathway, glyphosate triggered increased activity of ten-eleven translocation (TET)3. Combining glyphosate with enhanced expression of microRNA (miR) 182-5p associated with breast cancer induced tumor development in 50% of mice. Culture of primary cells from resected tumors revealed a luminal B (ER+/PR-/HER2-) phenotype in response to glyphosate-miR182-5p exposure with sensitivity to tamoxifen and invasive and migratory potentials. Tumor development could be prevented either by specifically inhibiting miR 182-5p or by treating glyphosate-miR 182-5p-cells with dimethyloxallyl glycine, an inhibitor of TET pathway. Looking for potential epigenetic marks of TET-mediated gene regulation under glyphosate exposure, we identified MTRNR2L2 and DUX4 genes, the hypomethylation of which was sustained even after stopping glyphosate exposure for 6 weeks. Our findings reveal that low pressure but sustained DNA hypomethylation occurring via the TET pathway primes cells for oncogenic response in the presence of another potential risk factor. These results warrant further investigation of glyphosate-mediated breast cancer risk.

Glyphosate does not substitute for glycine in proteins of actively dividing mammalian cells

OBJECTIVES

Glyphosate (N-phosphonomethyl glycine) and its commercial herbicide formulations have been shown to exert toxicity via various mechanisms. It has been asserted that glyphosate substitutes for glycine in polypeptide chains leading to protein misfolding and toxicity. However, as no direct evidence exists for glycine to glyphosate substitution in proteins, including in mammalian organisms, we tested this claim by conducting a proteomics analysis of MDA-MB-231 human breast cancer cells grown in the presence of 100 mg/L glyphosate for 6 days. Protein extracts from three treated and three untreated cell cultures were analysed as one TMT-6plex labelled sample, to highlight a specific pattern (+/+/+/-/-/-) of reporter intensities for peptides bearing true glyphosate treatment induced-post translational modifications as well as allowing an investigation of the total proteome.

RESULTS

Comparative statistical analysis of global proteome changes between glyphosate treated and non-treated samples did not show significant differences. Crucially, filtering of data to focus analysis on peptides potentially bearing glycine for glyphosate replacement revealed that the TMT reporter intensity pattern of all candidates showed conclusively that they are all false discoveries, with none displaying the expected TMT pattern for such a substitution. Thus, the assertion that glyphosate substitutes for glycine in protein polypeptide chains is incorrect.

Roundup®, but Not Roundup-Ready® Corn, Increases Mortality of Drosophila melanogaster

Genetically modified foods have become pervasive in diets of people living in the US. By far the most common genetically modified foods either tolerate herbicide application (HT) or produce endogenous insecticide (Bt). To determine whether these toxicological effects result from genetic modification per se, or from the increase in herbicide or insecticide residues present on the food, we exposed fruit flies, Drosophila melanogaster, to food containing HT corn that had been sprayed with the glyphosate-based herbicide Roundup®, HT corn that had not been sprayed with Roundup®, or Roundup® in a variety of known glyphosate concentrations and formulations. While neither lifespan nor reproductive behaviors were affected by HT corn, addition of Roundup® increased mortality with an LC50 of 7.1 g/L for males and 11.4 g/L for females after 2 days of exposure. Given the many genetic tools available, Drosophila are an excellent model system for future studies about genetic and biochemical mechanisms of glyphosate toxicity.

Glyphosate-based herbicides at low doses affect canonical pathways in estrogen positive and negative breast cancer cell lines

Glyphosate is a broad-spectrum herbicide that is used worldwide. It represents a potential harm to surface water, and when commercially mixed with surfactants, its uptake is greatly magnified. The most well-known glyphosate-based product is Roundup. This herbicide is potentially an endocrine disruptor and many studies have shown the cytotoxicity potential of glyphosate-based herbicides. In breast cancer (BC) cell lines it has been demonstrated that glyphosate can induce cellular proliferation via estrogen receptors. Therefore, we aimed to identify gene expression changes in ER+ and ER- BC cell lines treated with Roundup and AMPA, to address changes in canonical pathways that would be related or not with the ER pathway, which we believe could interfere with cell proliferation. Using the Human Transcriptome Arrays 2.0, we identified gene expression changes in MCF-7 and MDA-MB-468 exposed to low concentrations and short exposure time to Roundup Original and AMPA. The results showed that at low concentration (0.05% Roundup) and short exposure (48h), both cell lines suffered deregulation of 11 canonical pathways, the most important being cell cycle and DNA damage repair pathways. Enrichment analysis showed similar results, except that MDA-MB-468 altered mainly metabolic processes. In contrast, 48h 10mM AMPA showed fewer differentially expressed genes, but also mainly related with metabolic processes. Our findings suggest that Roundup affects survival due to cell cycle deregulation and metabolism changes that may alter mitochondrial oxygen consumption, increase ROS levels, induce hypoxia, damage DNA repair, cause mutation accumulation and ultimately cell death. To our knowledge, this is the first study to analyze the effects of Roundup and AMPA on gene expression in triple negative BC cells. Therefore, we conclude that both compounds can cause cellular damage at low doses in a relatively short period of time in these two models, mainly affecting cell cycle and DNA repair.

Toxicological Effects of Traumatic Acid and Selected Herbicides on Human Breast Cancer Cells: In Vitro Cytotoxicity Assessment of Analyzed Compounds

The main consequence of herbicides use is the presence of their residues in food of plant origin. A growing body of evidence indicates that herbicides cause detrimental effects upon human health while demonstrating a direct link of pesticides exposure with the occurrence of human chronic diseases, including cancer. There is a pressing need to develop our knowledge regarding interactions of food contaminants and food components both in vitro and in vivo. Pesticides are highly undesirable food contaminants, and traumatic acid (TA) is a very beneficial food ingredient, therefore we decided to study if TA may act as a compound that delays the stimulatory effect of pesticides on breast cancer cells. To analyze the potential effects that selected herbicides (MCPA, mesotrione, bifenox and dichlobenil) may have upon cancerous cells, we conducted studies of the cytotoxicity of physiological concentrations of four pesticides and the mix of TA with tested herbicides in three different breast cancer cell lines (MCF-7, ZR-75-1 and MDA-MB-231) and one normal healthy breast cell line MCF-12A. Based on the obtained results we conclude that TA in a concentration-dependent manner might influence selected effects of the studied herbicides for particular cancer cells lines.

The Ramazzini Institute 13-week pilot study glyphosate-based herbicides administered at human-equivalent dose to Sprague Dawley rats: effects on development and endocrine system

BACKGROUND

Glyphosate-based herbicides (GBHs) are broad-spectrum herbicides that act on the shikimate pathway in bacteria, fungi, and plants. The possible effects of GBHs on human health are the subject of an intense public debate for both its potential carcinogenic and non-carcinogenic effects, including potential effects on the endocrine system The present pilot study examine whether exposure to GBHs at the dose of glyphosate considered to be "safe" (the US Acceptable Daily Intake - ADI - of 1.75 mg/kg bw/day), starting from in utero life, affect the development and endocrine system across different life stages in Sprague Dawley (SD) rats.

METHODS

Glyphosate alone and Roundup Bioflow, a commercial brand of GBHs, were administered in drinking water at 1.75 mg/kg bw/day to F0 dams starting from the gestational day (GD) 6 (in utero) up to postnatal day (PND) 120. After weaning, offspring were randomly distributed in two cohorts: 8 M + 8F/group animals belonging to the 6-week cohort were sacrificed after puberty at PND 73 ± 2; 10 M + 10F/group animals belonging to the 13-week cohort were sacrificed at adulthood at PND 125 ± 2. Effects of glyphosate or Roundup exposure were assessed on developmental landmarks and sexual characteristics of pups.

RESULTS

In pups, anogenital distance (AGD) at PND 4 was statistically significantly increased both in Roundup-treated males and females and in glyphosate-treated males. Age at first estrous (FE) was significantly delayed in the Roundup-exposed group and serum testosterone concentration significantly increased in Roundup-treated female offspring from the 13-week cohort compared to control animals. A statistically significant increase in plasma TSH concentration was observed in glyphosate-treated males compared with control animals as well as a statistically significant decrease in DHT and increase in BDNF in Roundup-treated males. Hormonal status imbalances were more pronounced in Roundup-treated rats after prolonged exposure.

CONCLUSIONS

The present pilot study demonstrate that GBHs exposure, from prenatal period to adulthood, induced endocrine effects and altered reproductive developmental parameters in male and female SD rats. In particular, it was associated with androgen-like effects, including a statistically significant increase of AGDs in both males and females, delay of FE and increased testosterone in female.

Neonatal exposure to a glyphosate-based herbicide alters the histofunctional differentiation of the ovaries and uterus in lambs

The aim of the present study was to compare the effect of oral and subcutaneous exposure to a glyphosate-based herbicide (GBH) on the female reproductive system, specifically in the ovaries and uterus of prepubertal lambs. To this end, ewe lambs were exposed to a s.c. (n: 5) or an oral (n: 5) environmentally relevant dose of GBH (2 mg/kg/day) or to vehicle (controls, n: 12), from postnatal day (PND) 1 to PND14. Serum glyphosate and aminomethylphosphonic acid (AMPA) concentrations were measured on PND15 and PND45. The ovaries and uterus were obtained and weighed on PND45. Ovarian follicular dynamics and uterine morphological features were determined by picrosirius-hematoxylin staining. The proliferation marker Ki67 was evaluated by immunohistochemistry in ovarian and uterine samples. Glyphosate but not AMPA was detected in serum of exposed lambs on PND15, whereas neither glyphosate nor AMPA were detected on PND45. Controls were negative for glyphosate and AMPA on PND15 and PND45. GBH exposure did not affect ovarian or uterine weight. However, on PND45, the ovary of GBH-exposed lambs showed altered follicular dynamics, increased proliferation of granulosa and theca cells, and decreased mRNA expression of FSHR and GDF9, whereas their uterus showed decreased cell proliferation but no alterations in the histomorphology or gene expression. In conclusion, GBH exposure altered the ovarian follicular dynamics and gene expression, and the proliferative activity of the ovaries and uterus of lambs. It is noteworthy that all the adverse effects found in the ovaries and uterus of both GBH-exposed groups were similar, independently of the administration route.

Male mammary gland development and methylation status of estrogen receptor alpha in Wistar rats are modified by the developmental exposure to a glyphosate-based herbicide

Postnatal treatment with glyphosate-based herbicides (GBHs) induces endocrine-disrupting effects on the male rat mammary gland. In this study, the effects of developmental exposure to GBH on mammary gland growth and development, and the possible molecular mechanisms involved, were evaluated in pre- and post-pubertal male rats. To this end, pregnant rats were orally exposed through the food to 0, 3.5 or 350 mg GBH/kg bw/day from gestational day 9 until weaning. Mammary gland development and estradiol (E2) and testosterone (T) serum levels of male offspring were evaluated on postnatal day (PND)21 and PND60. Besides, prolactin (PRL) serum levels, proliferation index, androgen (AR) and estrogen receptor alpha (ESR1) expression, ESR1 alternative transcript mRNA levels, and DNA methylation status of ESR1 promoters were assessed on PND60. No differences between groups were observed in mammary gland development at PND21 or in E2 and T levels on both PNDs studied. On PND60, GBH3.5-exposed animals presented similar mammary gland histology but higher AR protein expression than controls, whereas GBH350-exposed males presented a less developed mammary gland, accompanied by a lower proliferation index, similar AR levels, and slightly increased PRL serum levels than controls. In both exposed groups, ESR1 expression was lower than in control rats, being lower in GBH350-exposed rats. GBH also altered the abundance of ESR1 transcript variants by hypermethylation of ESR1 promoters. GHB3.5 decreased only ESR1-OS expression, whereas GBH350 affected ESR1-O, OT and E1 expression. Our results show that developmental exposure to GBH induces epigenetic changes in ESR1, which could be responsible for the altered male mammary gland development observed in GBH350-exposed animals.

Epigenetic disruption of estrogen receptor alpha is induced by a glyphosate-based herbicide in the preimplantation uterus of rats

Previously, we have shown that perinatal exposure to a glyphosate-based herbicide (GBH) induces implantation failures in rats. Estrogen receptor alpha (ERα) is critical for successful implantation. ERα transcription is under the control of five promoters (E1, OT, O, ON, and OS), which yield different transcripts. Here, we studied whether perinatal exposure to a GBH alters uterine ERα gene expression and prompts epigenetic modifications in its regulatory regions during the preimplantation period. Pregnant rats (F0) were orally treated with 350 mg glyphosate/kg bw/day through food from gestational day (GD) 9 until weaning. F1 females were bred, and uterine samples were collected on GD5 (preimplantation period). ERα mRNA levels and its transcript variants were evaluated by RT-qPCR. Enzyme-specific restriction sites and predicted transcription factors were searched in silico in the ERα promoter regions to assess the methylation status using the methylation-sensitive restriction enzymes-PCR technique. Post-translational modifications of histones were studied by the chromatin immunoprecipitation assay. GBH upregulated the expression of total ERα mRNA by increasing the abundance of the ERα-O transcript variant. In addition, different epigenetic changes were detected in the O promoter. A decrease in DNA methylation was observed in one of the three sites evaluated in the O promoter. Moreover, histone H4 acetylation and histone H3 lysine 9 trimethylation (H3K9me3) were enriched in the O promoter in GBH-exposed rats, whereas H3K27me3 was decreased. All these alterations could account for the increase in ERα gene expression. Our findings show that perinatal exposure to a GBH causes long-term epigenetic disruption of the uterine ERα gene, which could be associated with the GBH-induced implantation failures.

Assessment of occupational exposure to pesticide mixtures with endocrine-disrupting activity

Occupational exposure to pesticide mixtures comprising active substance(s) and/or co-formulant(s) with known/possible endocrine-disrupting activity was assessed using long-term activity records for 50 professional operators representing arable and orchard cropping systems in Greece, Lithuania, and the UK. Exposure was estimated using the harmonised Agricultural Operator Exposure Model, and risk was quantified as a point of departure index (PODI) using the lowest no observed (adverse) effect level. Use of substances with known/possible endocrine activity was common, with 43 of the 50 operators applying at least one such active substance on more than 50% of spray days; at maximum, one UK operator sprayed five such active substances and 10 such co-formulants in a single day. At 95th percentile, total exposure was largest in the UK orchard system (0.041 × 10^-2 mg kg bw^-1 day^-1) whereas risk was largest in the Greek cropping systems (PODI 0.053 × 10^-1). All five cropping systems had instances indicating potential for risk when expressed at a daily resolution (maximum PODI 1.2-10.7). Toxicological data are sparse for co-formulants, so combined risk from complex mixtures of active substances and co-formulants may be larger in reality.

Integrin targeting of glyphosate and its cell adhesion modulation effects on osteoblastic MC3T3-E1 cells revealed by label-free optical biosensing

This study is a discovery of interesting and far reaching properties of the world leading herbicide active ingredient glyphosate. Here we demonstrate the cell adhesion-modifying characteristics of glyphosate affecting cellular interactions via Arg-Gly-Asp (RGD)-dependent integrins. This conclusion was supported by the observations that a glyphosate surface coating induced integrin-specific cell adhesion, while glyphosate in solution inhibited cell adhesion on an RGD-displaying surface. A sensitive, real-time, label-free, whole cell approach was used to monitor the cell adhesion kinetic processes with excellent data quality. The half maximal inhibitory concentration (IC50) for glyphosate was determined to be 0.47 ± 0.07% (20.6 mM) in serum-free conditions. A three-dimensional dissociation constant of 0.352 mM was calculated for the binding between RGD-specific integrins in intact MC3T3-E1 cells and soluble glyphosate by measuring its competition for RGD-motifs binding, while the affinity of those RGD-specific integrins to the RGD-motifs was 5.97 µM. The integrin-targeted affinity of glyphosate was proven using competitive binding assays to recombinant receptor αvβ3. The present study shows not only ligand-binding properties of glyphosate, but also illustrates its remarkable biomimetic power in the case of cell adhesion.

Glyphosate-based herbicide enhances the uterine sensitivity to estradiol in rats

In a previous work, we detected that postnatal exposure to a glyphosate-based herbicide (GBH) alters uterine development in prepubertal rats causing endometrial hyperplasia and increasing cell proliferation. Our goal was to determine whether exposure to low dose of a GBH during postnatal development might enhance the sensitivity of the uterus to an estrogenic treatment. Female Wistar pups were subcutaneously injected with saline solution (control) or GBH using the reference dose (2 mg/kg/day, EPA) on postnatal days (PND) 1, 3, 5 and 7. At weaning (PND21), female rats were bilaterally ovariectomized and treated with silastic capsules containing 17β-estradiol (E2, 1 mg/mL) until they were 2 months of age. On PND60, uterine samples were removed and processed for histology, immunohistochemistry and mRNA extraction to evaluate: (i) uterine morphology, (ii) uterine cell proliferation by the detection of Ki67, (iii) the expression of the estrogen receptors alpha (ESR1) and beta (ESR2) and (iv) the expression of WNT7A and CTNNB1. GBH-exposed animals showed increased luminal epithelial height and stromal nuclei density. The luminal and glandular epithelium were markedly hyperplastic in 43% of GBH-exposed animals. GBH exposure caused an increase in E2-induced cell proliferation in association with an induction of both ESR1 and ESR2. GBH treatment decreased membranous and cytoplasmic expression of CTNNB1 in luminal and glandular epithelial cells and increased WNT7A expression in the luminal epithelium. These results suggest that early postnatal exposure to a GBH enhances the sensitivity of the rat uterus to estradiol and induces histomorphological and molecular changes associated with uterine hyperplasia.

Perinatal exposure to a glyphosate-based herbicide impairs female reproductive outcomes and induces second-generation adverse effects in Wistar rats

Glyphosate-based herbicides (GBHs) are the most globally used herbicides raising the risk of environmental exposition. Here, we investigated whether perinatal exposure to low doses of a GBH alters the female reproductive performance, and/or induced second-generation effects related to congenital anomalies or growth alterations. Pregnant rats (F0) received a GBH through food, in a dose of 2 mg (GBH-LD: GBH-low dose group) or 200 mg (GBH-HD: GBH-high dose group) of glyphosate/kg bw/day from gestational day (GD) 9 until weaning. Body weight gain and vaginal canal-opening of F1 females were recorded. Sexually mature F1 females were mated to evaluate their reproductive performance by assessing the pregnancy rate, and on GD19, the number of corpora lutea, the implantation sites (IS) and resorption sites. To analyze second-generation effects on F2 offspring, we analyzed the fetal morphology on GD19, and assessed the fetal length and weight, and the placental weight. GBH exposure neither altered the body weight gain of F1 females, nor vaginal opening onset. Although all GBH-exposed F1 rats became pregnant, a lower number of IS was detected. F2 offspring from both GBH groups showed delayed growth, evidenced by lower fetal weight and length, associated with a higher incidence of small for gestational age fetuses. In addition, higher placental weight and placental index were found in F2 offspring from GBH-HD dams. Surprisingly, structural congenital anomalies (conjoined fetuses and abnormally developed limbs) were detected in the F2 offspring from GBH-HD group. In conclusion, perinatal exposure to low doses of a GBH impaired female reproductive performance and induced fetal growth retardation and structural congenital anomalies in F2 offspring.

Glyphosate induces growth of estrogen receptor alpha positive cholangiocarcinoma cells via non-genomic estrogen receptor/ERK1/2 signaling pathway

Previous studies showed that glyphosate stimulates breast cancer cell growth via estrogen receptors. The present study investigated the effect of glyphosate on the estrogen signaling pathway involved in the induction of cholangiocarcinoma (CCA) cell growth. HuCCA-1, RMCCA-1 and MMNK-1 were chosen for comparison. The effects of glyphosate on cell growth, cell cycle and molecular signaling pathways were measured. The results showed that HuCCA-1 cells expressed estrogen receptor alpha (ERα), while ERα was not detected in RMCCA-1 and MMNK-1 cells. ERα was mostly expressed in cytoplasmic compartment of HuCCA-1 cells. Estradiol (E2) (10-11-10-5 M) induced cell proliferation in HuCCA-1 but not in RMCCA-1 and MMNK-1 cells. Glyphosate at the same concentration range also induced HuCCA-1 cell proliferation. The S phase of the cell cycle, and protein levels of the cyclin family were significantly increased after treatment of glyphosate or E2. Both compounds also induced the expression of proliferative signaling-related proteins including ERα, VEGFR2, pERK, PI3K(p85), and PCNA. These effects of glyphosate and E2 were abolished by the ER antagonist, 4-hydroxytamoxifen and U0126, a MEK inhibitor. The data from this study indicate that glyphosate can induce cell growth in ERα positive CCA cells through non-genomic estrogen receptor/ERK1/2 signaling pathway.

Postnatal exposure to a glyphosate-based herbicide modifies mammary gland growth and development in Wistar male rats

Our aim was to evaluate whether postnatal exposure to a glyphosate-based herbicide (GBH) modifies mammary gland development in pre- and post-pubertal male rats. From postnatal day 1 (PND1) to PND7, male rats were injected subcutaneously every 48 h with either saline solution (vehicle) or 2 mg GBH/kg·bw. On PND21 and PND60, mammary gland and blood samples were collected. Estradiol (E2) and testosterone (T) serum levels, mammary gland histology, collagen fiber organization, mast cell infiltration, proliferation index, and estrogen (ESR1) and androgen receptor (AR) expression levels were evaluated. At PND21, GBH-exposed male rats exhibited greater development of the mammary gland with increased stromal collagen organization and terminal end buds (TEBs) compared to control rats. At PND60, the number of TEBs remained high and was accompanied by an increase in mast cell infiltration, proliferation and ESR1 expression in GBH-exposed male rats. In contrast, no effects were observed in E2 and T serum levels and AR expression in both days studied. Our results showed that a postnatal subacute treatment with GBH induces endocrine-disrupting effects in the male mammary gland in vivo, altering its normal development.

Glyphosate affects swine ovarian and adipose stromal cell functions

Although Glyphosate (GLY) is a widely used pesticide, its effects on ovarian function and stem cell differentiation are still largely unknown. Therefore, as a contribution on this subject, the present work reports an investigation of the in vitro effects of GLY on swine granulosa cells and adipose stromal cells (ASCs). The effect of GLY at different doses (0.2, 4 and 16 μg/mL) was evaluated on granulosa cells growth (BrDU incorporation and ATP production), steroidogenesis (17-β estradiol and progesterone secretion) and redox status (superoxide and nitric oxide production and non-enzymatic scavenging activity). GLY has been shown to inhibit cell growth, 17-β estradiol and non-enzymatic scavenging activity and to increase progesterone and nitric oxide secretion (P < 0.05). In addition, GLY significantly decreased the viability of ASCs (P < 0.001), and inhibited their adipogenic differentiation. These data indicate that GLY alters the main features of granulosa cells and ASCS thus suggesting that GLY could affect both reproductive function and adipose tissues homeostasis.

Glyphosate affects the secretion of regulators of uterine contractions in cows while it does not directly impair the motoric function of myometrium in vitro

The effects of pure glyphosate and its most popular product (brand name: Roundup) on the secretion of hormones involved in the regulation of myometrial contractions as well as their direct effects on myometrial contractions were examined. Myometrial strips as well as uterine and ovarian cells were taken from cows during the oestrous cycle and they were treated with both compounds at concentrations from their environmental range. Glyphosate stimulated the secretion of oestradiol from granulosa cells while both herbicides increased and decreased oxytocin (OT) and progesterone secretion from luteal cells respectively. However only Roundup stimulated mRNA expression of the precursor of OT. Both compounds decreased the secretion of prostaglandins from endometrial cells while they exerted no effect on the basal and OT-stimulated force of myometrial contractions. The studied herbicides did not directly impair the motoric function of the myometrium. However our data indicate the potential of these compounds to disturb the secretory functions of the ovaries and uterus which can lead to the deregulation of uterine contractions and to the impairment of fertilisation or to difficulties in the maintenance of gestation.

Overview of air pollution and endocrine disorders

Over recent years, many environmental pollutant chemicals have been shown to possess the ability to interfere in the functioning of the endocrine system and have been termed endocrine disrupting chemicals (EDCs). These compounds exist in air as volatile or semi-volatile compounds in the gas phase or attached to particulate matter. They include components of plastics (phthalates, bisphenol A), components of consumer goods (parabens, triclosan, alkylphenols, fragrance compounds, organobromine flame retardants, fluorosurfactants), industrial chemicals (polychlorinated biphenyls), products of combustion (polychlorinated dibenzodioxins/furans, polyaromatic hydrocarbons), pesticides, herbicides, and some metals. This review summarizes current knowledge concerning the sources of EDCs in air, measurements of levels of EDCs in air, and the potential for adverse effects of EDCs in air on human endocrine health.

Computational biochemical investigation of the binding energy interactions between an estrogen receptor and its agonists

We present the energy profiles of estrogen receptor–agonist ligand interactions in atomic detail using a quantum biochemical approach.