Prostate Cancer Risk and DNA Methylation Signatures in Aging Rats following Developmental BPA Exposure: A Dose-Response Analysis

Exploring novel insights into the molecular mechanisms underlying Bisphenol A-induced toxicity: A persistent threat to human health

Bisphenol A (BPA) is a ubiquitous industrial chemical used in the production of polycarbonate plastics and epoxy resins, found in numerous consumer products. Despite its widespread use, its potential adverse health effects have raised significant concerns. This review explores the molecular mechanisms and evidence-based literature underlying BPA-induced toxicities and its implications for human health. BPA is an endocrine-disrupting chemical (EDC) which exhibits carcinogenic properties by influencing various receptors, such as ER, AhR, PPARs, LXRs, and RARs. It induces oxidative stress and contributes to cellular dysfunction, inflammation, and DNA damage, ultimately leading to various toxicities including but not limited to reproductive, cardiotoxicity, neurotoxicity, and endocrine toxicity. Moreover, BPA can modify DNA methylation patterns, histone modifications, and non-coding RNA expression, leading to epigenetic changes and contribute to carcinogenesis. Overall, understanding molecular mechanisms of BPA-induced toxicity is crucial for developing effective strategies and policies to mitigate its adverse effects on human health.

PAQR4 oncogene: a novel target for cancer therapy

Despite decades of basic and clinical research and trials of promising new therapies, cancer remains a major cause of morbidity and mortality due to the emergence of drug resistance to anticancer drugs. These resistance events have a very well-understood underlying mechanism, and their therapeutic relevance has long been recognized. Thus, drug resistance continues to be a major obstacle to providing cancer patients with the intended "cure". PAQR4 (Progestin and AdipoQ Receptor Family Member 4) gene is a recently identified novel protein-coding gene associated with various human cancers and acts through different signaling pathways. PAQR4 has a significant influence on multiple proteins that may regulate various gene expressions and may develop chemoresistance. This review discusses the roles of PAQR4 in tumor immunity, carcinogenesis, and chemoresistance. This paper is the first review, discussing PAQR4 in the pathogenesis of cancer. The review further explores the PAQR4 as a potential target in various malignancies.

Maternal inulin alleviates high-fat diet-induced lipid disorder in offspring by epigenetically modulating hypothalamus feeding circuit-related genes

Increasing evidence supports the existence of fetal-originated adult diseases. Recent research indicates that the intrauterine environment affects the fetal hypothalamic energy intake center. Inulin is a probiotic that can moderate metabolic disorders, but whether maternal inulin intervention confers long-term metabolic benefits to lipid metabolism in offspring in their adult lives and the mechanism involved are unknown. Here, we used a maternal overnutrition model that was induced by excess energy intake before and during pregnancy and lactation and maternal inulin intervention was performed during pregnancy and lactation. The hypothalamic genome methylation in offspring was analyzed using a methylation array. The results showed that maternal inulin treatment modified the maternal high-fat diet (HFD)-induced increases in body weight, adipose tissue weight, and serum insulin and leptin levels and decreases in serum adiponectin levels. Maternal inulin intervention regulated the impairments in hypothalamic leptin resistance, induced the methylation of Socs3, Npy, and Il6, and inhibited the methylation of Lepr in the hypothalamus of offspring. In conclusion, maternal inulin intervention modifies offspring lipid metabolism, and the underlying mechanism involves the methylation of genes in the hypothalamus feeding circuit.

Widely targeted quantitative lipidomics reveal lipid remodeling in adipose tissue after long term of the combined exposure to bisphenol A and fructose

Adipose tissue is the main organ that stores lipids and it plays important roles in metabolic balance in the body. We recently reported in Human and Experimental Toxicology that the combined exposure to BPA and fructose may interfere with energy metabolism of adipose tissue. However, it is still unclear whether the combined exposure to BPA and fructose has the possibility to induce lipid remodeling in adipose tissue. In the present study, we performed a widely targeted quantitative lipidomic analysis of the adipose tissue of rats after 6 months of BPA and fructose combined exposure. We totally determined 734 lipid molecules in the adipose tissue of rats. Principal component analysis (PCA) showed the group of the combined exposure to higher-dose (25 μg/kg every other day) BPA and fructose can be distinguished from the groups of control, higher-dose BPA exposure and fructose exposure clearly. Partial least squares-discriminant analysis (PLS-DA) and univariate statistical analysis displayed lipids of PC(18:0_ 20:3), TG(8:0_14:0_16:0), TG(12:0_14:0_16:1), TG(10:0_16:0_16:1), TG(12:0_ 14:0_18:1), TG(14:0_ 16:0_16:1), TG(14:0_14:1_16:1), TG(8:0_ 16:1_16:2), TG(14:1_16:1_ 16:1), TG(16:1_18:1_18:1), TG(16:0_16:1_20:4) and TG(15:0_18:1_ 24:1) may contributed the most to the discrimination. These findings indicated that combined exposure to BPA and fructose has the potential to cause lipid remodeling in adipose tissue.

Integrative analysis of DNA methylome and transcriptome reveals epigenetic regulation of bisphenols-induced cardiomyocyte hypertrophy

Cardiac hypertrophy, a kind of cardiomyopathic abnormality, might trigger heart contractile and diastolic dysfunction, and even heart failure. Currently, bisphenols (BPs) including bisphenol A (BPA), and its alternatives bisphenol AF (BPAF), bisphenol F (BPF) and bisphenol S (BPS) are ubiquitously applied in various products and potentially possess high cardiovascular risks for humans. However, the substantial experimental evidences of BPs on heart function, and their structure-related effects on cardiomyocyte hypertrophy are still urgently needed. DNA methylation, a typical epigenetics, play key roles in BPs-induced transcription dysregulation, thereby affecting human health including cardiovascular system. Thus, in this study, we performed RNA-seq and reduced representation bisulfite sequencing (RRBS) to profile the landscapes of BPs-induced cardiotoxicity and to determine the key roles of DNA methylation in the transcription. Further, the capabilities of three BPA analogues, together with BPA, in impacting heart function and changing DNA methylation and transcription were compared. We concluded that similar to BPA, BPAF, BPF and BPS exposure deteriorated heart function in a mouse model, and induced cardiomyocyte hypertrophy in a H9c2 cell line. BPAF, BPF and BPS all played BPA-like roles in both transcriptive and methylated hierarchies. Moreover, we validated the expression levels of four cardiomyocyte hypertrophy related candidate genes, Psmc1, Piptnm2, Maz and Dusp18, which were all upregulated and with DNA hypomethylation. The findings on the induction of BPA analogues on cardiomyocyte hypertrophy and DNA methylation revealed their potential detrimental risks in heart function of humans.

Evaluating endocrine disrupting chemicals: A perspective on the novel assessments in CLARITY-BPA

BACKGROUND

The Consortium Linking Academic and Regulatory Insights on Bisphenol A Toxicity (CLARITY-BPA) was a collaborative research effort to better link academic research with governmental guideline studies. This review explores the secondary goal of CLARITY-BPA: to identify endpoints or technologies from CLARITY-BPA and prior/concurrent literature from these laboratories that may enhance the capacity of rodent toxicity studies to detect endocrine disrupting chemicals (EDCs).

METHODS

A systematic literature search was conducted with search terms for BPA and the CLARITY-BPA participants. Relevant studies employed a laboratory rodent model and reported results on 1 of the 10 organs/organ systems evaluated in CLARITY-BPA (brain and behavior, cardiac, immune, mammary gland, ovary, penile function, prostate gland and urethra, testis and epididymis, thyroid hormone and metabolism, and uterus). Study design and findings were summarized, and a risk-of-bias assessment was conducted.

RESULTS

Several endpoints and methods were identified as potentially helpful to detect effects of EDCs. For example, molecular and quantitative morphological approaches were sensitive in detecting alterations in early postnatal development of the brain, ovary, and mammary glands. Hormone challenge studies mimicking human aging reported increased susceptibility of the prostate to disease following developmental BPA exposure. Statistical analyses for nonmonotonic dose responses, and computational approaches assessing multiple treatment-related outcomes concurrently in linked hormone-sensitive organ systems, reported effects at low BPA doses.

CONCLUSIONS

This review provided an opportunity to evaluate the unique insights provided by nontraditional assessments in CLARITY-BPA to identify technologies and endpoints to enhance detection of EDCs in future studies.

Diesel exhaust particles exposure induces liver dysfunction: Exploring predictive potential of human circulating microRNAs signature relevant to liver injury risk

Diesel exhaust particles (DEP) pollution should be taken seriously because it is an extensive environmental and occupational health concern. Exploring early effect biomarkers is crucial for monitoring and managing DEP-associated health risk assessment. Here, we found that serum levels of 67 miRNAs were dysregulated in DEP exposure group. Notably, 20 miRNAs were identified as each having a significant dose-response relationship with the internal exposure level of DEP. Further, we revealed that the DEP exposure could affect the liver function of subjects and that 7 miRNAs (including the well-known liver injury indicator, miR-122-5p) could serve as the novel epigenetic-biomarkers (epi-biomarkers) to reflect the liver-specific response to the DEP exposure. Importantly, an unprecedented prediction model using these 7 miRNAs was established for the assessment of DEP-induced liver injury risk. Finally, bioinformatic analysis indicated that the unique set of miRNA panel in serum might also contribute to the molecular mechanism of DEP exposure-induced liver damage. These results broaden our understanding of the adverse health outcomes of DEP exposure. Noteworthy, we believe this study could shed light on roles and functions of epigenetic biomarkers from environmental exposure to health outcomes by revealing the full chain of exposure-miRNAs-molecular pathways-disease evidence.

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.

The State of Research and Weight of Evidence on the Epigenetic Effects of Bisphenol A

Bisphenol A (BPA) is a high-production-volume chemical with numerous industrial and consumer applications. BPA is extensively used in the manufacture of polycarbonate plastics and epoxy resins. The widespread utilities of BPA include its use as internal coating for food and beverage cans, bottles, and food-packaging materials, and as a building block for countless goods of common use. BPA can be released into the environment and enter the human body at any stage during its production, or in the process of manufacture, use, or disposal of materials made from this chemical. While the general population is predominantly exposed to BPA through contaminated food and drinking water, non-dietary exposures through the respiratory system, integumentary system, and vertical transmission, as well as other routes of exposure, also exist. BPA is often classified as an endocrine-disrupting chemical as it can act as a xenoestrogen. Exposure to BPA has been associated with developmental, reproductive, cardiovascular, neurological, metabolic, or immune effects, as well as oncogenic effects. BPA can disrupt the synthesis or clearance of hormones by binding and interfering with biological receptors. BPA can also interact with key transcription factors to modulate regulation of gene expression. Over the past 17 years, an epigenetic mechanism of action for BPA has emerged. This article summarizes the current state of research on the epigenetic effects of BPA by analyzing the findings from various studies in model systems and human populations. It evaluates the weight of evidence on the ability of BPA to alter the epigenome, while also discussing the direction of future research.

Endocrine-disrupting chemicals (EDCs) and cancer: new perspectives on an old relationship

PURPOSE

Environmental endocrine-disrupting chemicals (EDCs) are a mixture of chemical compounds capable to interfere with endocrine axis at different levels and to which population is daily exposed. This paper aims to review the relationship between EDCs and breast, prostate, testicle, ovary, and thyroid cancer, discussing carcinogenic activity of known EDCs, while evaluating the impact on public health.

METHODS

A literature review regarding EDCs and cancer was carried out with particular interest on meta-analysis and human studies.

RESULTS

The definition of EDCs has been changed through years, and currently there are no common criteria to test new chemicals to clarify their possible carcinogenic activity. Moreover, it is difficult to assess the full impact of human exposure to EDCs because adverse effects develop latently and manifest at different ages, even if preclinical and clinical evidence suggest that developing fetus and neonates are most vulnerable to endocrine disruption.

CONCLUSION

EDCs represent a major environmental and health issue that has a role in cancer development. There are currently some EDCs that can be considered as carcinogenic, like dioxin and cadmium for breast and thyroid cancer; arsenic, asbestos, and dioxin for prostate cancer; and organochlorines/organohalogens for testicular cancer. New evidence supports the role of other EDCs as possible carcinogenic and pregnant women should avoid risk area and exposure. The relationship between EDCs and cancer supports the need for effective prevention policies increasing public awareness.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Hydroxymethylation and Epigenetic Drugs: New Insights into the Diagnosis and Treatment in Epigenetics of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly lethal and heterogeneous malignancy with multiple genetic alternations and complex signaling pathways. The complexity and multifactorial nature of HCC pose a tremendous challenge regarding its diagnosis and treatment. Emerging evidence has indicated an important regulatory role of epigenetic modifications in HCC initiation and progression. Epigenetic modifications are stably heritable gene expression traits caused by changing the accessibility of chromatin structure and genetic activity without alteration in the DNA sequence and have been gradually recognized as a hallmark of cancer. In addition, accumulating data suggest a potential value of altered hydroxymethylation in epigenetic modifications and therapeutics targeting the epigenetically mediated regulation. As such, probing the epigenetic field in the era of precision oncology is a valid avenue for promoting the accuracy of early diagnosis and improving the oncological prognosis of HCC patients. This review focuses on the diagnostic performance and clinical utility of 5-hydroxymethylated cytosine, the primary intermediate product of the demethylation process, for early HCC diagnosis and discusses the promising applications of epigenetic-based therapeutic regimens for HCC.

Effects of perinatal exposure to bisphenol A on induction of prostate cancer in Sprague Dawley rats by MNU and testosterone

Perinatal and neonatal exposure to bisphenol A (BPA) has been linked to enhancement of prostate carcinogenesis in rats induced by combined treatment with estradiol and testosterone, but human data are lacking. This study aimed to determine the effects of perinatal BPA exposure on induction of prostate cancer in rats by sequential treatment with N-methyl-N-nitrosamine (MNU) and continuous low dose administration of testosterone. Pregnant Sprague Dawley rats were exposed to BPA administered by subcutaneous Alzet minipumps at doses of 2.5 or 25 µg/kg body weight/day from gestational day 9 until postnatal day 28 when pups were weaned providing exposure of offspring in utero and via the mother's milk. At 10-12 weeks of age, one male offspring per litter was treated with an intraperitoneal injection of MNU after hormonal stimulation of prostatic cell proliferation followed two weeks later by subcutaneous insertion of Silastic implants containing testosterone until the termination of the study 57-58 weeks after MNU injection. The perinatal BPA exposure did not significantly affect the incidence of prostate carcinomas which was slightly lower in exposed rats (33-23 %) than in control animals (40 %). Carcinomas in all accessory sex glands combined were also insignificantly less frequent in exposed (46-48 %) than in control rats (60 %). The incidence of malignant tumors at any site in the body was significantly lower in exposed rats (81-65 %) than in controls (93 %). In conclusion, perinatal BPA exposure did not significantly modify prostate cancer induction by MNU plus testosterone in rats, unlike the enhancement of prostate carcinogenesis induced by treatments involving estradiol administration. Which of the two models of prostate carcinogenesis is more relevant for the human situation is unclear at present.

Individual and Combined Effect of Bisphenol A and Bisphenol AF on Prostate Cell Proliferation through NF-κB Signaling Pathway

The ubiquitous environmental endocrine disruptor bisphenol A (BPA) can induce prostatic dysfunction. However, to date, studies have focused little on the perturbations of prostate health initiated by the BPA derivative bisphenol AF (BPAF) and co-exposure to bisphenol compounds. An in vivo study orally administrated male rats with BPA (10, 90 μg/kg), BPAF (10, 90 μg/kg) and the inhibitor of nuclear transcription factor-κB (NF-κB), pyrrolidinedithiocarbamate (PDTC, 100 mg/kg). Based on the anatomical analysis, pathological observations and PCNA over-expression, we considered that low-dose BPA and BPAF facilitated ventral prostatic hyperplasia in rats. The results of IHC and ELISA mirrored the regulation of NF-κB p65, COX-2, TNF-α and EGFR in BPA- and BPAF-induced prostatic toxicity. An in vitro study found that the additive effect of combined exposure to BPA (10 nM) and BPAF (10 nM) could cause an elevation in the proliferation of and a reduction in the apoptosis level of human prostate stromal cells (WPMY-1) and fibroblasts (HPrF). Meanwhile, the underlying biomarkers of the NF-κB signaling pathway also involved the abnormal proliferative progression of prostate cells. The findings recapitulated the induction of BPAF exposure and co-treatment with BPA and BPAF on prostatic hyperplasia and emphasized the modulation of the NF-κB signaling pathway.

Impact of chronic exposure of rats to bisphenol A from perinatal period to adulthood on intraprostatic levels of 5α-reductase isozymes, aromatase, and genes implicated in prostate cancer development

The synergetic effect of estrogens and androgens is known to play a crucial role in the physiopathology of the prostate gland. Bisphenol A (BPA) is an endocrine disrupting compound that can interfere with endocrine hormone functioning and thereby influence prostate development. The objective of this study was to examine the impact on prostate expression of aromatase, 5α-R isozymes, and prostate cancer-related genes of exposure to low doses of BPA from perinatal period to adulthood. Vehicle or BPA (2.5 μg/kg b.w./day) was administered to gestating Wistar rats from gestational day 12 (GD12) to parturition and then to their male pups from postnatal day 1 (PND1) until euthanization on PND90. Their prostate glands were examined by qRT-PCR, Western blot, PCR array, and morphological study. mRNA and protein levels of 5α-R2 were significantly reduced and mRNA and protein levels of aromatase were significantly increased in BPA-treated animals, which also showed modifications of 8 out of the 84 key genes implicated in the development of prostate cancer. Because BPA interferes with genes involved in intraprostatic androgen and estrogen production and others implicated in prostate cancer, research is warranted into the prostate disease risk associated with chronic low-dose BPA exposure throughout life.

Comprehensive analysis of emerging flame retardants, a risk factor to prostate cancer?

Among man-made chemicals, flame retardants have caused great environmental concerns. Several studies in recent years have investigated potential sources of flame retardants, environmental distribution, exposure to wild animals and humans and toxicity. However, studies focusing on the prediction of toxicity of flame retardants are limited. Herein, toxicological and tumor databases were applied to evaluate the potential correlation between emerging flame retardants (EFRs) and tumors. Further analysis also showed that EFRs may be associated with prostate cancer (PCa). After constructing an EFR-related prognostic prediction model, it was established that EFR-related genes showed a strong prognostic predictive value among PCa patients. In addition, compared with the clinical characteristics model (including age, Gleason score, prostate-specific antigen level, T stage and N stage), a prognostic predictive model-based risk score demonstrated a better predictive value of PCa. The AUC of the 31-gene prognostic signature at 1, 3 and 5 years was 0.843, 0.824 and 0.819, respectively. In addition, the AUC of the risk score, Gleason score, age, PSA level, T stage and N stage were 0.843, 0.637, 0.414, 0.490, 0.668 and 0.517, respectively. Our analysis provides a comprehensive map of EFR interaction genes and demonstrated a new direction for environmentally hazardous materials and diseases.

Bibliometric Analysis of the Toxicity of Bisphenol A

Bisphenol A (BPA) is used worldwide and research on the toxicity of BPA has advanced rapidly in the last few decades. This study aimed to evaluate the global scientific output of toxicity of BPA and explore the hot spots and research trends. All available articles related to the toxicity of BPA until 2022 were retrieved from the Web of Science Core Collection database. The VOSviewer, a bibliometric analysis software, was used to analyze the information of included articles, including countries/institutions, international cooperation, journals, citations, and keywords. Among 1644 retrieved articles, 1611 eligible studies were identified for analysis, and the annual publications increased with time in the past three decades. China and the United States were the most active contributors in this field. Chinese Academy of Sciences and the Dow chemical company conducted relatively more research than others about BPA toxicity. The journal “Chemosphere” published the most studies on “BPA toxicity”. Before 2015, most research focused on estrogenic activity and the test system mainly utilized animal experiments. However, in recent years, research related to toxic mechanisms of BPA at the cellular level and the toxicity of its analogs have received widespread attention. Considering some critical research gaps, future research on BPA toxicology should probably focus on the molecular biology of toxic mechanism, mixture toxicity, and co-exposure of BPA substitutes. This study will help researchers understand past and current research trends, hot spots, and trends of toxicity studies of BPA and, thus, contribute to further research and risk management of BPA.

CpG site-specific methylation as epi-biomarkers for the prediction of health risk in PAHs-exposed populations

Environmental insults can lead to alteration in DNA methylation of specific genes. To address the role of altered DNA methylation in prediction of polycyclic aromatic hydrocarbons (PAHs) exposure-induced genetic damage, we recruited two populations, including diesel engine exhausts (low-level) and coke oven emissions (high-level) exposed subjects. The positive correlation was observed between the internal exposure marker (1-hydroxypyrene) and the extents of DNA damage (P < 0.05). The methylation of representative genes, including TRIM36, RASSF1a, and MGMT in peripheral blood lymphocytes was quantitatively examined by bisulfite-pyrosequencing assay. The DNA methylation of these three genes in response to PAHs exposure were changed in a CpG-site-specific manner. The identified hot CpG site-specific methylation of three genes exhibited higher predictive power for DNA damage than the respective single genes in both populations. Furthermore, the dose-response relationship analysis revealed a nonlinear U-shape curve of TRIM36 or RASSF1a methylation in combined population, which led to determination of the threshold of health risk. Furthermore, we established a prediction model for genetic damage based on the unidirectional-alteration MGMT methylation levels. In conclusion, this study provides new insight into the application of multiple epi-biomarkers for health risk assessment upon PAHs exposure.

Maternal Oxidized Soybean Oil Administration in Rats during Pregnancy and Lactation Alters the Intestinal DNA Methylation in Offspring

As a food contaminant, oxidized oil or lipid oxidative products have been proven to exert toxicological effects on the growth and development of animals and humans. Research shows that maternal oxidative stress damage might transmit to another generation by epigenetic modulation. However, current evidence is still not clear on the mechanism of the effects of dietary oxidized oil during pregnancy on the two generations. This study employed a rat model fed with oxidized soybean oil (OSO) during pregnancy and lactation to explore the effects of the oxidative degree (0, 200, 400, and 800 mequiv of O₂/kg) on the placental RNA methylation and DNA methylation in offspring jejunum. The results showed that following the ingestion of OSO, the placental genes of different m⁶A methylation were significantly enriched to nutrient metabolic processes and hormone activity. In addition, the intestine in offspring hypofunctioned observably, such as reducing the height of villi and the level of anti-inflammatory cytokine. Furthermore, maternal intake of OSO during pregnancy can damage the intestinal barrier function of offspring by inhibiting the proliferation and differentiation of intestinal epithelial cells and reducing the activity of intestinal DNA methyltransferase. In conclusion, this study reinforces the assertion that maternal OSO consumption during gestation and lactation negatively affects the placental health and intestinal development of suckling pups.

Bisphenol A exposure triggers the malignant transformation of prostatic hyperplasia in beagle dogs via cfa-miR-204/KRAS axis

The prostatic toxicity of bisphenol A (BPA) exposure is mainly associated with hormonal disturbances, thus interfering with multiple signal pathways and increasing the susceptibility to prostatic lesions. This study concentrates predominantly on the potential effect and mechanisms of low-dose BPA exposure on prostates in adult beagle dogs. The dogs were orally given BPA (2, 6, 18 μg/kg/day) and vehicle for 8 weeks, followed by blood collection and dissection. The ascended organ coefficient and volume of prostates, thickened epithelium, as well as histopathological observation have manifested that BPA exposure could trigger the aberrant prostatic hyperplasia in beagle dogs. Hormone level detection revealed that the ratios of estradiol (E₂) to testosterone (T) (E₂/T) and prolactin (PRL) to T (PRL/T) were up-regulated in the serum from BPA group. Based on microRNA (miRNA) microarray screening and functional enrichment analysis, BPA might facilitate the progression of prostate tumorigenesis in beagle dogs via cfa-miR-204 and its downstream target KRAS oncogene. Subsequently, the overexpression of KRAS, CDKN1A, MAPK1, VEGFA, BCL2 and PTGS2 was validated. These findings provide a series of underlying targets for preventing the initiation and metastasis of BPA-induced prostatic hyperplasia and tumorigenesis, while the regulatory relationship headed with KRAS requires further investigation.

Effects of bisphenol a on hematological, serum biochemical, and histopathological biomarkers in bighead carp (Aristichthys nobilis) under long-term exposure

Bisphenol A (BPA) is one of the highest volume chemicals produced in the world and is frequently used in dental sealants, water bottles, food, and beverage packaging. Due to persistent applications, BPA has become a potential threat to a variety of organisms including public health. In this study, a total of 80 bighead carps were randomly placed in different four groups (A-D). Fish in groups B, C, and D were exposed to BPA @500, 1000, and 1500 μg/L, respectively for 60 days. Fish in group A served as an untreated control group. The body weight was significantly decreased while the absolute and relative weight of different visceral organs increased significantly (p < 0.05) in fish exposed to higher concentration (1500 μg/L) of BPA. Results on proximate analysis showed significantly lower values of crude proteins, lipids, and moisture contents while increased contents of ash in muscles of treated fish. The erythrocyte counts, hemoglobin concentration, lymphocytes, and monocytes significantly decreased while total leukocyte and neutrophil counts significantly increased in treated fish. Results exhibited that different serum biochemistry parameters like serum albumin and total proteins decreased significantly (p < 0.05) while alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), urea, creatinine, glucose, cholesterol, and lactate dehydrogenase (LDH) increased significantly (p < 0.05) in treated fish. Histopathological ailments like pyknosis, degeneration of glomeruli, increased Bowman's space, ceroid formation in kidneys while ceroid formation, hemorrhages, pyknosis, karyorrhexis, karyolysis, nuclear hypertrophy, and eccentric nuclei were observed in the liver of treated fish. Histological observation of different sections of the brain of treated fish exhibited degeneration of neurons in the cerebellum, lipofuscin deposition, microgliosis, necrotic neurons, inflammatory cells, and hemorrhage. Results on light microscopic observation of different sections of the heart of bighead carp revealed necrosis, inflammatory reaction, neutrophilic myocarditis, and hemorrhages. In conclusion, it is suggested that BPA induces adverse effects on physical, blood-biochemical parameters, and histopathological changes in multiple visceral tissues of exposed fish.

The HeyL-Aromatase Axis Promotes Cancer Stem Cell Properties by Endogenous Estrogen-Induced Autophagy in Castration-Resistant Prostate Cancer

Treatment of patients with castration-resistant prostate cancer (CRPC) remains a major clinical challenge. We previously showed that estrogenic effects contribute to CRPC progression and are primarily caused by the increased endogenous estradiol produced via highly expressed aromatase. However, the mechanism of aromatase upregulation and its role in CRPC are poorly described. In this study, we report that HeyL is aberrantly upregulated in CRPC tissues, and its expression is positively correlated with aromatase levels. HeyL overexpression increased endogenous estradiol levels and estrogen receptor-α (ERα) transcriptional activity by upregulating CYP19A1 expression, which encodes aromatase, enhancing prostate cancer stem cell (PCSC) properties in PC3 cells. Mechanistically, HeyL bound to the CYP19A1 promoter and activated its transcription. HeyL overexpression significantly promoted bicalutamide resistance in LNCaP cells, which was reversed by the aromatase inhibitor letrozole. In PC3 cells, the HeyL-aromatase axis promoted the PCSC phenotype by upregulating autophagy-related genes, while the autophagy inhibitor chloroquine (CQ) suppressed the aromatase-induced PCSC phenotype. The activated HeyL-aromatase axis promoted PCSC autophagy via ERα-mediated estrogenic effects. Taken together, our results indicated that the HeyL-aromatase axis could increase endogenous estradiol levels and activate ERα to suppress PCSC apoptosis by promoting autophagy, which enhances the understanding of how endogenous estrogenic effects influence CRPC development.

In utero exposure to endocrine-disrupting chemicals, maternal factors and alterations in the epigenetic landscape underlying later-life health effects

Widespread persistence of endocrine-disrupting chemicals (EDCs) in the environment has mandated the need to study their potential effects on an individual's long-term health after both acute and chronic exposure periods. In this review article a particular focus is given on in utero exposure to EDCs in rodent models which resulted in altered epigenetic programming and transgenerational effects in the offspring causing disrupted reproductive and metabolic phenotypes. The literature to date establishes the impact of transgenerational effects of EDCs potentially associated with epigenetic mediated mechanisms. Therefore, this review aims to provide a comprehensive overview of epigenetic programming and it's regulation in mammals, primarily focusing on the epigenetic plasticity and susceptibility to exogenous hormone active chemicals during the early developmental period. Further, we have also in depth discussed the epigenetic alterations associated with the exposure to selected EDCs such as Bisphenol A (BPA), di-2-ethylhexyl phthalate (DEHP) and vinclozlin upon in utero exposure especially in rodent models.

Morphometric Analysis of Rat Prostate Development: Roles of MEK/ERK and Rho Signaling Pathways in Prostatic Morphogenesis

The molecular mechanisms underlying prostate development can provide clues for prostate cancer research. It has been demonstrated that MEK/ERK signaling downstream of androgen-targeted FGF10 signaling directly induces prostatic branching during development, while Rho/Rho-kinase can regulate prostate cell proliferation. MEK/ERK and Rho/Rho kinase regulate myosin light chain kinase (MLCK), and MLCK regulates myosin light chain phosphorylation (MLC-P), which is critical for cell fate, including cell proliferation, differentiation, and apoptosis. However, the roles and crosstalk of the MEK/ERK and Rho/Rho kinase signaling pathways in prostatic morphogenesis have not been examined. In the present study, we used numerical and image analysis to characterize lobe-specific rat prostatic branching during postnatal organ culture and investigated the roles of FGF10-MEK/ERK and Rho/Rho kinase signaling pathways in prostatic morphogenesis. Prostates exhibited distinctive lobe-specific growth and branching patterns in the ventral (VP) and lateral (LP) lobes, while exogenous FGF10 treatment shifted LP branching towards a VP branching pattern. Treatment with inhibitors of MEK1/2, Rho, Rho kinase, or MLCK significantly inhibited VP growth and blocked branching morphogenesis, further supporting critical roles for MEK/ERK and Rho/Rho kinase signaling pathways in prostatic growth and branching during development. We propose that MLCK-regulated MLC-P may be a central downstream target of both signaling pathways in regulating prostate morphogenesis.

Integration of Epigenetic Mechanisms into Non-Genotoxic Carcinogenicity Hazard Assessment: Focus on DNA Methylation and Histone Modifications

Epigenetics involves a series of mechanisms that entail histone and DNA covalent modifications and non-coding RNAs, and that collectively contribute to programing cell functions and differentiation. Epigenetic anomalies and DNA mutations are co-drivers of cellular dysfunctions, including carcinogenesis. Alterations of the epigenetic system occur in cancers whether the initial carcinogenic events are from genotoxic (GTxC) or non-genotoxic (NGTxC) carcinogens. NGTxC are not inherently DNA reactive, they do not have a unifying mode of action and as yet there are no regulatory test guidelines addressing mechanisms of NGTxC. To fil this gap, the Test Guideline Programme of the Organisation for Economic Cooperation and Development is developing a framework for an integrated approach for the testing and assessment (IATA) of NGTxC and is considering assays that address key events of cancer hallmarks. Here, with the intent of better understanding the applicability of epigenetic assays in chemical carcinogenicity assessment, we focus on DNA methylation and histone modifications and review: (1) epigenetic mechanisms contributing to carcinogenesis, (2) epigenetic mechanisms altered following exposure to arsenic, nickel, or phenobarbital in order to identify common carcinogen-specific mechanisms, (3) characteristics of a series of epigenetic assay types, and (4) epigenetic assay validation needs in the context of chemical hazard assessment. As a key component of numerous NGTxC mechanisms of action, epigenetic assays included in IATA assay combinations can contribute to improved chemical carcinogen identification for the better protection of public health.

Combined Effects of Different Endocrine-Disrupting Chemicals (EDCs) on Prostate Gland

Endocrine-disrupting chemicals (EDCs) belong to a heterogeneous class of environmental pollutants widely diffused in different aquatic and terrestrial habitats. This implies that humans and animals are continuously exposed to EDCs from different matrices and sources. Moreover, pollution derived from anthropic and industrial activities leads to combined exposure to substances with multiple mechanisms of action on the endocrine system and correlated cell and tissue targets. For this reason, specific organs, such as the prostate gland, which physiologically are under the control of hormones like androgens and estrogens, are particularly sensitive to EDC stimulation. It is now well known that an imbalance in hormonal regulation can cause the onset of various prostate diseases, from benign prostate hyperplasia to prostate cancer. In this review, starting with the description of normal prostate gland anatomy and embryology, we summarize recent studies reporting on how the multiple and simultaneous exposure to estrogenic and anti-androgenic compounds belonging to EDCs are responsible for an increase in prostate disease incidence in the human population.

Prenatal exposure to bisphenols affects pregnancy outcomes and offspring development in rats

The objective of this study was to evaluate the effects of gestational exposure to low doses of bisphenol A (BPA), bisphenol S (BPS), and bisphenol F (BPF) on pregnancy outcomes and offspring development. Pregnant Sprague-Dawley rats were orally dosed with vehicle, 5 μg/kg body weight (BW)/day of BPA, BPS and BPF, or 1 μg/kg BW/day of BPF on gestational days 6-21. Pregnancy and gestational outcomes, including number of abortions and stillbirths, were monitored. Male and female offspring were subjected to morphometry at birth, followed by pre- and post-weaning body weights, post-weaning food and water intakes, and adult organ weights. Ovarian follicular counts were also obtained from adult female offspring. We observed spontaneous abortions in over 80% of dams exposed to 5 μg/kg of BPF. BPA exposure increased Graafian follicles in female offspring, while BPS and BPF exposure decreased the number of corpora lutea, suggesting reduced ovulation rates. Moreover, BPA exposure increased male kidney and prostate gland weights, BPF decreased epididymal adipose tissue weights, and BPS had modest effects on male abdominal adipose tissue weights. Prenatal BPS exposure reduced anogenital distance (AGD) in male offspring, suggesting possible feminization, whereas both BPS and BPA induced oxidative stress in the testes. These results indicate that prenatal exposure to BPF affects pregnancy outcomes, BPS alters male AGD, and all three bisphenols alter certain organ weights in male offspring and ovarian function in female offspring. Altogether, it appears that prenatal exposure to BPA or its analogues can induce reproductive toxicity even at low doses.

Inflammatory repercussions in female steroid responsive glands after perinatal exposure to bisphenol A and 17-β estradiol

The mammary gland (MG) and female prostate are plastic reproductive organs which are highly responsive to hormones. Thus, endocrine disruptors, such as bisphenol A (BPA) and exogenous estrogens, negatively affect glandular homeostasis. In addition to previously described alterations, changes in inflammatory markers expression also trigger the development of a microenvironment that contributes to tumor progression. The current work aimed to evaluate the inflammatory responses of the MG and prostate gland to BPA (50 µg/kg) and 17-β estradiol (35 µg/kg) exposure during the perinatal window of susceptibility. The results showed that at 6 months of age there was an increase in the number of phospho-STAT3 (P-STAT3) positive cells in the female prostate from animals perinatally exposed to 50 µg/kg BPA daily. In addition, the number of macrophages increased in these animals in comparison with nonexposed animals, as shown by the F4/80 marker. Despite an increase in the incidence of lobuloalveolar and intraductal hyperplasia, the MG did not show any difference in the expression of the four inflammatory markers evaluated: tumor necrosis factor-α, COX-2, P-STAT3, and F4/80. Analysis of both glands from the same animal led to the conclusion that exposure to endocrine disruptors during the perinatal window of susceptibility leads to different inflammatory responses in different reproductive organs. As the prostate is more susceptible to these inflammatory mechanisms, it is reasonable to affirm that possible neoplastic alterations in this organ are related to changes in the inflammatory pattern of the stroma, a characteristic that is not evident in the MG.

EDCs and male urogenital cancers

Male sex determination and sexual differentiation occur between 6-12 weeks of gestation. During the "male programming window" the fetal testes start to produce testosterone that initiates the development of the male reproductive tract. Exposure to endocrine disrupting chemicals (EDCs) able to mimic or disrupt steroid hormone actions may disrupt testicular development and adversely impact reproductive health at birth, during puberty and adulthood. The testicular dysgenesis syndrome (TDS) occurs as a result inhibition of androgen action on fetal development preceding Sertoli and Leydig cell dysfunction and may result from direct or epigenetic effects. Hypospadias, cryptorchidism and poor semen quality are elements of TDS, which may be considered a risk factor for testicular germ cell cancer (TGCC). Exposure to estrogen or estrogenic EDCs results in developmental estrogenization/estrogen imprinting in the rodent for prostate cancer (PCa). This can disrupt prostate histology by disorganization of the epithelium, prostatic intraepithelial neoplasia (PIN) lesions, in particular high-grade PIN (HGPIN) lesions which are precursors of prostatic adenocarcinoma. These defects persist throughout the lifespan of the animal and later in life estrogen exposure predispose development of cancer. Exposure of pregnant dams to vinclozolin, a competitive anti-androgen, and results in prominent, focal regions of inflammation in all exposed animals. The inflammation closely resembles human nonbacterial prostatitis that occurs in young men and evidence indicates that inflammation plays a central role in the development of PCa. In conclusion, in utero exposure to endocrine disrupters may predispose to the development of TDS, testicular cancer (TCa) and PCa and are illustrations of Developmental Origins of Health and Disease (DOHaD).

The regulation mechanisms and the Lamarckian inheritance property of DNA methylation in animals

DNA methylation is a stable and heritable epigenetic mechanism, of which the main functions are stabilizing the transcription of genes and promoting genetic conservation. In animals, the direct molecular inducers of DNA methylation mainly include histone covalent modification and non-coding RNA, whereas the fundamental regulators of DNA methylation are genetic and environmental factors. As is well known, competition is present everywhere in life systems, and will finally strike a balance that is optimal for the animal's survival and reproduction. The same goes for the regulation of DNA methylation. Genetic and environmental factors, respectively, are responsible for the programmed and plasticity changes of DNA methylation, and keen competition exists between genetically influenced procedural remodeling and environmentally influenced plastic alteration. In this process, genetic and environmental factors collaboratively decide the methylation patterns of corresponding loci. DNA methylation alterations induced by environmental factors can be transgenerationally inherited, and exhibit the characteristic of Lamarckian inheritance. Further research on regulatory mechanisms and the environmental plasticity of DNA methylation will provide strong support for understanding the biological function and evolutionary effects of DNA methylation.

A comprehensive review on the carcinogenic potential of bisphenol A: clues and evidence

Bisphenol A [BPA; (CH₃)₂C(C₆H₄OH)₂] is a synthetic chemical used as a precursor material for the manufacturing of plastics and resins. It gained attention due to its high chances of human exposure and predisposing individuals at extremely low doses to diseases, including cancer. It enters the human body via oral, inhaled, and dermal routes as leach-out products. BPA may be anticipated as a probable human carcinogen. Studies using in vitro cell lines, rodent models, and epidemiological analysis have convincingly shown the increasing susceptibility to cancer at doses below the oral reference dose set by the Environmental Protection Agency for BPA. Furthermore, BPA exerts its toxicological effects at the genetic and epigenetic levels, influencing various cell signaling pathways. The present review summarizes the available data on BPA and its potential impact on cancer and its clinical outcome.

Breast and prostate glands affected by environmental substances (Review)

Environmental endocrine disruptor chemicals are substances that can alter the homeostasis of the endocrine system in living organisms. They can be released from several products used in daily activities. Once in the organism, they can disrupt the endocrine function by mimicking or blocking naturally occurring hormones due to their similar chemical structure. This endocrine disruption is the most important cause of the well‑known hormone‑associate types of cancer. Additionally, it is decisive to determine the susceptibility of each organ to these compounds. Therefore, the present review aimed to summarize the effect of different environmental substances such as bisphenol A, dichlorodiphenyltrichloroethane and polychlorinated biphenyls in both the mammary and the prostate tissues. These organs were chosen due to their association with the hormonal system and their common features in carcinogenic mechanisms. Outcomes derived from the present review may provide evidence that should be considered in future debates regarding the effects of endocrine disruptors on carcinogenesis.

From Wingspread to CLARITY: a personal trajectory

In the three decades since endocrine disruption was conceptualized at the Wingspread Conference, we have witnessed the growth of this multidisciplinary field and the accumulation of evidence showing the deleterious health effects of endocrine-disrupting chemicals. It is only within the past decade that, albeit slowly, some changes regarding regulatory measures have taken place. In this Perspective, we address some historical points regarding the advent of the endocrine disruption field and the conceptual changes that endocrine disruption brought about. We also provide our personal recollection of the events triggered by our serendipitous discovery of oestrogenic activity in plastic, a founder event in the field of endocrine disruption. This recollection ends with the CLARITY study as an example of a discordance between 'science for its own sake' and 'regulatory science' and leads us to offer a perspective that could be summarized by the motto attributed to Ludwig Boltzmann: "Nothing is more practical than a good theory".

Developmental estrogenization: Prostate gland reprogramming leads to increased disease risk with aging

While estrogens are involved in normal prostate morphogenesis and function, inappropriate early-life estrogenic exposures, either in type, dose or timing, can reprogram the prostate gland and lead to increased disease risk with aging. This process is referred to as estrogen imprinting or developmental estrogenization of the prostate gland. The present review discusses published and new evidence for prostatic developmental estrogenization that includes extensive research in rodent models combined with epidemiology findings that together have helped to uncover the architectural and molecular underpinnings that promote this phenotype. Complex interactions between steroid receptors, developmental morphoregulatory factors, epigenetic machinery and stem-progenitor cell targets coalesce to hard wire structural, cellular and epigenomic reorganization of the tissue which retains a life-long memory of early-life estrogens, ultimately predisposing the gland to prostatitis, hyperplasia and carcinogenesis with aging.

The role of epigenetics in the reproductive toxicity of environmental endocrine disruptors

Environmental endocrine disruptors (EEDs) seriously endanger human health by interfering with the normal function of reproductive systems. In males, EEDs can affect sperm formation and semen quality as well spermatogenesis, ultimately reducing fertility. In females, EEDs can affect uterine development and the expression levels of reproduction-related genes, ultimately reducing female fertility and the normal development of the fetus. There are a large number of putative mechanisms by which EEDs can induce reproductive toxicity, and many studies have shown the involvement of epigenetics. In this review, we summarize the role of DNA methylation, noncoding RNAs, genomic imprinting, chromatin remodeling and histone modification in the reproductive toxicity of EEDs.

Chronic exposure to microcystin-LR increases the risk of prostate cancer and induces malignant transformation of human prostate epithelial cells

Microcystins-LR (MC-LR) acts as a possible carcinogen for humans and causes a serious risk to public environmental health. The current study aimed to evaluate the interaction between MC-LR exposure and prostate cancer development and elucidate the underlying mechanism. In this study, mice were exposed to MC-LR at various doses for 180 days. MC-LR was able to induce the progression of prostatic intraepithelial neoplasia (PIN) and microinvasion. Furthermore, MC-LR notably increased angiogenesis and susceptibility to prostate cancer in vivo. In vitro, over 25 weeks of MC-LR exposure, normal human prostate epithelial (RWPE-1) cells increased secretion of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and colony formation, features typical for cancer cells. These MC-LR-transformed prostate epithelial cells displayed increased expression of forkhead box M1 (FOXM1) and cyclooxygenase-2 (COX-2); abrogation of FOXM1 or COX-2 activity by specific inhibitors could abolish the invasion and migration of MC-LR-treated cells. In conclusion, we have provided compelling evidence demonstrating the induction of a malignant phenotype in human prostate epithelial cells and the in vivo development of prostate cancer by exposure to MC-LR, which might be a potential tumor promoter in the progression of prostate cancer.

Data integration, analysis, and interpretation of eight academic CLARITY-BPA studies

"Consortium Linking Academic and Regulatory Insights on BPA Toxicity" (CLARITY-BPA) was a comprehensive "industry-standard" Good Laboratory Practice (GLP)-compliant 2-year chronic exposure study of bisphenol A (BPA) toxicity that was supplemented by hypothesis-driven independent investigator-initiated studies. The investigator-initiated studies were focused on integrating disease-associated, molecular, and physiological endpoints previously found by academic scientists into an industry standard guideline-compliant toxicity study. Thus, the goal of this collaboration was to provide a more comprehensive dataset upon which to base safety standards and to determine whether industry-standard tests are as sensitive and predictive as molecular and disease-associated endpoints. The goal of this report is to integrate the findings from the investigator-initiated studies into a comprehensive overview of the observed impacts of BPA across the multiple organs and systems analyzed. For each organ system, we provide the rationale for the study, an overview of methodology, and summarize major findings. We then compare the results of the CLARITY-BPA studies across organ systems with the results of previous peer-reviewed studies from independent labs. Finally, we discuss potential influences that contributed to differences between studies. Developmental exposure to BPA can lead to adverse effects in multiple organs systems, including the brain, prostate gland, urinary tract, ovary, mammary gland, and heart. As published previously, many effects were at the lowest dose tested, 2.5μg/kg /day, and many of the responses were non-monotonic. Because the low dose of BPA affected endpoints in the same animals across organs evaluated in different labs, we conclude that these are biologically - and toxicologically - relevant.

Identification of potential molecular pathways involved in prostate carcinogenesis in offspring exposed to maternal malnutrition

The developmental origins of health and disease concept links adult diseases with early-life exposure to inappropriate environmental conditions. Intrauterine and postnatal malnutrition may lead to an increased incidence of type 2 diabetes, obesity, and cardiovascular diseases. Maternal malnutrition (MM) has also been associated with prostate carcinogenesis. However, the molecular mechanisms associated with this condition remain poorly understood. Using a proteomic analysis, we demonstrated that MM changed the levels of proteins associated with growth factors, estrogen signaling, detoxification, and energy metabolism in the prostate of both young and old rats. These animals also showed increased levels of molecular markers of endoplasmic reticulum function and histones. We further performed an in silico analysis that identified commonly deregulated proteins in the ventral prostate of old rats submitted to MM with a mouse model and patients with prostate cancer. In conclusion, our results demonstrated that estrogenic signaling pathways, endoplasmic reticulum functions, energy metabolism, and molecular sensors of protein folding and Ca2+ homeostasis, besides histone, and RAS-GTPase family appear to be involved in this process. Knowledge of these factors may raise discussions regarding the role of maternal dietary intervention as a public policy for the lifelong prevention of chronic diseases.

Urinary bisphenol A and its interaction with ESR1 genetic polymorphism associated with non-small cell lung cancer: findings from a case-control study in Chinese population

Bisphenol A (BPA), a well-known endocrine disruptor, was reported to promote migration and invasion of lung cancer cells, but findings in human study is absent. A case-control study in Chinese population was conducted to evaluate the association between BPA exposure and non-small cell lung cancer (NSCLC), and explore the interaction between BPA exposure and estrogen-related genetic polymorphism on NSCLC. BPA concentrations were measured in urine samples using an UHPLC-MS method and rs2046210 in estrogen receptor α (ESR1) gene was genotyped by TaqMan genotyping system. Logistic regression was performed to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for the association analyses. As a result, 615 NSCLC cases and 615 healthy controls were enrolled from Wuhan, central China. The mean age was 58.0 (SD: 7.9) years old for controls and 59.2 (SD: 8.8) years old for cancer cases. The creatinine-adjusted BPA levels were significantly higher in NSCLC cases than that in healthy controls (median: 0.97 vs 0.73 μg/L, P < 0.001). Exposure to high levels of BPA was significantly associated with NSCLC (adjusted OR = 1.91, 95%CI: 1.39-2.62, P < 0.001 for the highest quartile). We also observed a shallow concave dose-response relationship about the overall association between BPA and NSCLC. Moreover, interaction analyses showed that BPA exposure interacted multiplicatively with rs2046210, with a marginal P value (P = 0.049), to contribute to NSCLC. In conclusion, exposure to high levels BPA may be associated with NSCLC and the relationship may be modified by genetic polymorphism in ESR1.

Potential Mechanisms of Bisphenol A (BPA) Contributing to Human Disease

Bisphenol A (BPA) is an organic synthetic compound serving as a monomer to produce polycarbonate plastic, widely used in the packaging for food and drinks, medical devices, thermal paper, and dental materials. BPA can contaminate food, beverage, air, and soil. It accumulates in several human tissues and organs and is potentially harmful to human health through different molecular mechanisms. Due to its hormone-like properties, BPA may bind to estrogen receptors, thereby affecting both body weight and tumorigenesis. BPA may also affect metabolism and cancer progression, by interacting with GPR30, and may impair male reproductive function, by binding to androgen receptors. Several transcription factors, including PPARγ, C/EBP, Nrf2, HOX, and HAND2, are involved in BPA action on fat and liver homeostasis, the cardiovascular system, and cancer. Finally, epigenetic changes, such as DNA methylation, histones modification, and changes in microRNAs expression contribute to BPA pathological effects. This review aims to provide an extensive and comprehensive analysis of the most recent evidence about the potential mechanisms by which BPA affects human health.

Gene expression profiling in dorsolateral prostates of prepubertal and adult Sprague-Dawley rats dosed with estradiol benzoate, estradiol, and testosterone

The imbalance of testosterone to estradiol ratio has been related to the development of prostate diseases. Although rat models of prostate diseases induced by endocrine-disrupting chemicals (EDCs) and/or hormone exposure are commonly used to analyze gene expression profiles in the prostate, most studies utilize a single endpoint. In this study, microarray analysis was used for gene expression profiling in rat prostate tissue after exposure to EDCs and sex hormones over multiple time points (prepubertal through adulthood). We used dorsolateral prostate tissues from Sprague-Dawley rats (male offspring) and postnatally administered estradiol benzoate (EB) on postnatal days (PNDs) 1, 3, and 5, followed by treatment with additional hormones [estradiol (E) and testosterone (T)] on PNDs 90-200, as described by Ho et al. Microarray analysis was performed for gene expression profiling in the dorsolateral prostate, and the results were validated via qRT-PCR. The genes in cytokine-cytokine receptor interaction, cell adhesion molecules, and chemokines were upregulated in the EB+T+E group on PNDs 145 and 200. Moreover, early-stage downregulation of anti-inflammatory gene: bone morphogenetic protein 7 gene was observed. These findings suggest that exposure to EB, T, and E activates multiple pathways and simultaneously downregulates anti-inflammatory genes. Interestingly, these genes are reportedly expressed in prostate cancer tissues/cell lines. Further studies are required to elucidate the mechanism, including analyses using human prostate tissues.

The Use and Misuse of Historical Controls in Regulatory Toxicology: Lessons from the CLARITY-BPA Study

For many endocrine-disrupting chemicals (EDCs) including Bisphenol A (BPA), animal studies show that environmentally relevant exposures cause harm; human studies are consistent with these findings. Yet, regulatory agencies charged with protecting public health continue to conclude that human exposures to these EDCs pose no risk. One reason for the disconnect between the scientific consensus on EDCs in the endocrinology community and the failure to act in the regulatory community is the dependence of the latter on so-called "guideline studies" to evaluate hazards, and the inability to incorporate independent scientific studies in risk assessment. The Consortium Linking Academic and Regulatory Insights on Toxicity (CLARITY) study was intended to bridge this gap, combining a "guideline" study with independent hypothesis-driven studies designed to be more appropriate to evaluate EDCs. Here we examined an aspect of "guideline" studies, the use of so-called "historical controls," which are essentially control data borrowed from prior studies to aid in the interpretation of current findings. The US Food and Drug Administration authors used historical controls to question the plausibility of statistically significant BPA-related effects in the CLARITY study. We examined the use of historical controls on 5 outcomes in the CLARITY "guideline" study: mammary neoplasms, pituitary neoplasms, kidney nephropathy, prostate inflammation and adenomas, and body weight. Using US Food and Drug Administration-proposed historical control data, our evaluation revealed that endpoints used in "guideline" studies are not as reproducible as previously held. Combined with other data comparing the effects of ethinyl estradiol in 2 "guideline" studies including CLARITY-BPA, we conclude that near-exclusive reliance on "guideline" studies can result in scientifically invalid conclusions.

Tumor-Associated Macrophages (TAM) are recruited to the aging prostate epithelial lesions and become intermingled with basal cells

BACKGROUND

Prostate cancer remains one of the most common cancers in men. Macrophages are thought to be important regulators in cancers, and their potential involvement in prostate cancer should not be overlooked. Therefore, the association between macrophages and the pre-tumorous changes in prostate epithelium during aging deserves further investigation.

OBJECTIVES

We sought to investigate whether macrophages would be recruited into the prostate epithelium that display pathological lesions commonly found during aging.

MATERIALS AND METHODS

Prostates of aging rats, with and without treatment with a combination of testosterone and estradiol, were examined for premalignant and malignant epithelial lesions. For comparison, prostates of castrated rats were also investigated.

RESULTS

Intraepithelial macrophages were found restricted to areas of premalignant and malignant lesions. An unprecedented interaction between macrophages and basal cells was observed in the aging pathological lesions. The intraepithelial macrophages were associated with autophagy, in contrast to those found after castration. In prostate lesions, the intraepithelial macrophages had TAM phenotype (CD68+/iNOS+/CD206+/ARG+), denoting a possible involvement in cancer progression. However, M2 macrophages (CD68+/CD163+) were recruited into the epithelium after castration, possibly to phagocytize cells undergoing apoptosis.

DISCUSSION AND CONCLUSION

In conclusion, macrophages were recruited into the prostate epithelium and presented diverse phenotypes and morphology, consistent with changes reflected in the hormonal environment. Macrophages with the TAM phenotype were found restricted to areas of premalignant and malignant lesions in aging prostates, denoting a possible involvement in cancer progression. In contrast, M2 macrophages were found in the regressed epithelium after castration.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Bisphenol A-Induced Epigenetic Changes and Its Effects on the Male Reproductive System

Bisphenol A (BPA) is a widespread chemical agent which can exert detrimental effects on the male reproductive system. Exposure to BPA has been shown to induce several epigenetic modifications in both animal and human cells. Specifically, BPA could not only modify the methylation pattern of multiple genes encoding proteins related to reproductive physiology but also directly influence the genes responsible for DNA methylation. BPA effects include hormonal alterations, microscopic and macroscopic alteration of male reproductive organs, and inheritable epigenetic changes involving human reproduction. BPA exposure was also linked to prostate cancer. This review aims to show the current scenario of BPA-induced epigenetic changes and its effects on the male reproductive system. Possible strategies to counter the toxic effect of BPA were also addressed.

The effects of different bisphenol derivatives on oxidative stress, DNA damage and DNA repair in RWPE-1 cells: A comparative study

Bisphenol A (BPA) is a well-known endocrine disruptor and it is widely used mainly in the plastics industry. Due to recent reports on its possible impact on health (particularly on the male reproductive system), bisphenol F (BPF) and bisphenol S (BPS) are now being used as alternatives. In this study, RWPE-1 cells were used as a model to compare cytotoxicity, oxidative stress-causing potential and genotoxicity of these chemicals. In addition, the effects of the bisphenol derivatives were assessed on DNA repair proteins. RWPE-1 cells were incubated with BPA, BPF, and BPS at concentrations of 0-600 μM for 24 h. The inhibitory concentration 20 (IC₂₀ , concentration that causes 20% of cell viability loss) values for BPA, BPF, and BPS were 45, 65, and 108 μM, respectively. These results indicated that cytotoxicity potentials were ranked as BPA > BPF > BPS. We also found alterations in superoxide dismutase, glutathione peroxidase and glutathione reductase activities, and glutathione and total antioxidant capacity in all bisphenol-exposed groups. In the standard and modified Comet assay, BPS produced significantly higher levels of DNA damage vs the control. DNA repair proteins (OGG1, Ape-1, and MyH) involved in the base excision repair pathway, as well as p53 protein levels were down-regulated in all of the bisphenol-exposed groups. We found that the BPA alternatives were also cytotoxic and genotoxic, and changed the expressions of DNA repair enzymes. Therefore, further studies are needed to assess whether they can be used safely as alternatives to BPA or not.

Untangling the association between environmental endocrine disruptive chemicals and the etiology of male genitourinary cancers

Endocrine disrupting chemicals disrupt normal physiological function of endogenous hormones, their receptors, and signaling pathways of the endocrine system. Most endocrine disrupting chemicals exhibit estrogen/androgen agonistic and antagonistic activities that impinge upon hormone receptors and related pathways. Humans are exposed to endocrine disrupting chemicals through food, water and air, affecting the synthesis, release, transport, metabolism, binding, function and elimination of naturally occurring hormones. The urogenital organs function as sources of steroid hormones, are targeted end organs, and participate within systemic feedback loops within the endocrine system. The effects of endocrine disruptors can ultimately alter cellular homeostasis leading to a broad range of health effects, including malignancy. Human cancer is characterized by uncontrolled cell proliferation, mechanisms opposing cell-death, development of immortality, induction of angiogenesis, and promotion of invasion/metastasis. While hormonal malignancies of the male genitourinary organs are the second most common types of cancer, the molecular effects of endocrine disrupting chemicals in hormone-driven cancers has yet to be fully explored. In this commentary, we examine the molecular evidence for the involvement of endocrine disrupting chemicals in the genesis and progression of hormone-driven cancers in the prostate, testes, and bladder. We also report on challenges that have to be overcome to drive our understanding of these chemicals and explore the potential avenues of discovery that could ultimately allow the development of tools to prevent cancer in populations where exposure is inevitable.

Global and region-specific post-transcriptional and post-translational modifications of bisphenol A in human prostate cancer cells

Bisphenol A (BPA), as synthetic monomer used in the production of polycarbonate plastic and epoxy resins, has endocrine disruptor properties and high risk on human health. Epigenetic alterations could act an important role in BPA-induced toxicity, but its mechanism has not been fully understood. We investigated the effects of BPA on gene expression of chromatin modifying enzymes, promoter methylation of tumor suppressor genes and histone modifications in human prostate carcinoma cells (PC-3). IC₅₀ value of BPA was determined as 217 and 190 μM in PC-3 cells by MTT and NRU tests, respectively. We revealed an increase in global levels of 5-methylcytocine and 5-hydroxymethylcytocine at 10 μM of BPA for 96 h. We observed a significant increase on promoter DNA methylation and decrease on gene expression of p16 gene while no change was observed for Cyclin D2 and Rassf1. Significant changes were observed in global histone modifications (H3K9ac, H3K9me3, H3K27me3, and H4K20me3) in PC-3 cells. According to these results, we investigated wide-range epigenetic modifications using PCR arrays. After 96 h BPA exposure, chromatin modifying enzymes including KDM5B and NSD1 were significantly downregulated. Also, promoter methylation of tumor suppressor genes including BCR, GSTP1, LOX, MGMT, NEUROG1, PDLIM4, PTGS2, PYCARD, TIMP3, TSC2 and ZMYDN10 altered significantly. ChIP results showed that H3K9ac, H3K9me3 and H3K27me3 modifications on p16 gene showed significant increases after 1 and 10 μM of BPA exposure. In conclusion, epigenetic signatures such as DNA methylation and histone modifications could be proposed as molecular biomarkers of BPA-induced prostate cancer progression.