Bisphenol AF exerts estrogenic activity in MCF-7 cells through activation of Erk and PI3K/Akt signals via GPER signaling pathway

Evaluation of effects of bisphenol analogs AF, S, and F on viability, proliferation, production of selected cancer-related factors, and expression of selected transcripts in Caov-3 human ovarian epithelial cell line

Bisphenol A (BPA) has been a substantial additive in plastics until the reports on its adverse effects have led to its restrictions and replacement. Monitoring studies document the increasing occurrence of bisphenol analogs, however, data on their effects and risks is still insufficient. Based on the indications that BPA might contribute to ovarian cancer pathogenesis, we examined effects of the analogs AF (BPAF), S (BPS) and F (BPF) (10-9-10-4 M) on the Caov-3 epithelial cancer cells, including the impact on cell viability, proliferation, oxidative stress, and production and expression of several factors and genes related to ovarian cancer. At environmentally relevant doses, bisphenols did not exert significant effects. At the highest concentration, BPAF caused varied alterations, including decreased cell viability and proliferation, caspase activation, down-regulation of PCNA and BIRC5, elevation of IL8, VEGFA, MYC, PTGS2 and ABCB1 expressions. Only BPA (10-4 M) increased IL-6, IL-8 and VEGFA output by the Caov-3 cells. Each bisphenol induced generation of reactive oxygen species and decreased superoxide dismutase activity at the highest concentration. Although the effects were observed only in the supraphysiological doses, the results indicate that certain bisphenol analogs might affect several ovarian cancer cell characteristics and merit further investigation.

G-Protein Coupled Receptor 1 Is Involved in Tetrachlorobisphenol A-Induced Inflammatory Response in Jurkat Cells

Estrogens can affect the immune inflammatory response through estrogen receptor alpha (ERα), but the specific role of estrogen member receptor G-protein coupled receptor 1 (GPER1) in this process remains unclear. In this study, we evaluated the effects of tetrachlorobisphenol A (TCBPA), which has estrogen activity, on immune inflammatory-related indicators of Jurkat cells, as well as investigated the role of GPER1 in these effects. The results showed that TCBPA at lower concentrations significantly promoted the viability of Jurkat cells, whereas higher concentrations decreased cell viability. TCBPA at concentrations ranging from 1 to 25 μM increased the intracellular reactive oxygen species (ROS) levels. Additionally, treatment with 10 μM TCBPA increased the protein expression of ERα and GPER1, elevated the phosphorylation of protein kinase B (p-Akt), and upregulated the mRNA levels of GPER1, Akt, and phosphoinositide 3-kinase (PI3K) genes. Treatment with 10 μM TCBPA also upregulated the protein or gene expression of pro-inflammatory cytokines, such as interleukins (IL1β, IL2, IL6, IL8, IL12α) and tumor necrosis factor alpha (TNFα) in Jurkat cells. Furthermore, pretreatment with a GPER1 inhibitor G15 significantly reduced the mRNA levels of Akt induced by 10 μM TCBPA. Moreover, the upregulation of mRNA expression of RelA (p65), TNFα, IL6, IL8, and IL12α induced by 10 μM TCBPA was also significantly attenuated after G15 pretreatment. These findings suggest that TCBPA upregulates the expression of genes related to inflammatory responses by activating the GPER1-mediated PI3K/Akt signaling pathway. This study provides new insights into the mechanism of TCBPA-induced inflammatory response.

Evaluation of the chronic toxicity of bisphenol A and bisphenol AF to sea cucumber Apostichopus japonicus after long-term single and combined exposure at environmental relevant concentration

Bisphenols are emerging endocrine disrupting pollutant, and several studies have reported that they are already ubiquitous in various environmental matrices and intend to deposit in sediment. The primary sources of bisphenols are river and sewage discharge. Sea cucumber (Apostichopus japonicus), a typical deposit feeder, is one of the most important commercial marine species in Aisa. However, the effects of the bisphenol A (BPA) and its analogues bisphenol AF (BPAF) on sea cucumber was unclear. In this study, we carried out field survey in major sea cucumber farming areas in northern China, with the aim of determining which bisphenol analogue is the major bisphenol contamination in this aquaculture area. The results showed that the presence of BPAF was detected in four sampling sites (Dalian, Tangshan, Laizhou, and Longpan). The mean level of BPAF in Laizhou sediment samples was the highest which reached to 9.007 ± 4.702 μ g/kg. Among the seawater samples, the BPAF only have been detected in the samples collected at Longpan. (0.011 ± 0.003 μ g/L). Furthermore, we conducted an experiment to evaluate the single and combined toxicity of BPA and BPAF on sea cucumbers. The concentrations were informed by the findings based on the results of field research. (0.1, 1.0, and 10 μ g/L). After exposure, the body weight gain, and specific growth rate showed no significant changes (P > 0.05). We observed the histological alterations in respiratory tree of treated sea cucumbers including the fusion and detachment of lining epithelial tissue, and increase of lumen space. However, the catalase (CAT), malondialdehyde (MDA), and glutathione (GSH) activity was not significantly changed (P > 0.05). We evaluated the effects of BPA and BPAF through calculating the integrated biomarker response index (IBR), and the results indicated that the toxicity of combined treatment was higher than single treatment. Additionally, BPAF exposure to A. japonicus was more toxic than BPA.

Bisphenol chemicals in colostrum from Shanghai, China during 2006-2019: Concentration, temporal variation, and potential influence on birth parameters

Bisphenol A (BPA) and its alternatives bisphenol S (BPS) and bisphenol F (BPF) are identified as endocrine disruptors that have negative impacts on infant growth. Their temporal variations in human milk and potential effects on fetal growth are not well known. In this study, colostrum collecting at four time points between 2006 and 2019 and paired urine in 2019 from Shanghai, China, were analyzed for eight bisphenols. The total concentrations in colostrum in 2019 were up to 3.43 ng/mL, with BPA being dominant, followed by BPS and BPF. BPA levels in colostrum noticeably decreased from 2010 to 2013. Additionally, obvious percentage changes in bisphenols were observed in 2019. The BPA concentrations in paired colostrum and urine were not significantly correlated. High levels of BPA in colostrum were linked to a significant reduction in birth head circumference in 2019 (p = 0.031). BPA and BPS in colostrum might have similar negative effect on fetal growth in 2019, but these effects were generally non-significant. Further studies are needed to testify the potential impact. The hazard indexes for infants in the first week of life were below 1, suggesting no obvious health risks. However, the high contribution from BPA still warrants further attention.

Effects of trichlorobisphenol A on the expression of proteins and genes associated with puberty initiation in GT1-7 cells and the relevant molecular mechanism

This study evaluated the effects of Cl3BPA on kisspeptin-G-protein coupled receptor 54 (GPR54)/gonadotropin-releasing hormone (GnRH) (KGG) signals and analyzed the roles of estrogen receptor alpha (ERɑ) and G-protein coupled estrogen receptor 1 (GPER1) in regulating KGG signals. The results showed that Cl3BPA at 50 μM increased the levels of intracellular reactive oxygen species (ROS) and GnRH, upregulated the protein levels of kisspeptin and the expression of fshr, lhr and gnrh1 genes related to KGG in GT1-7 cells. In addition, 50 μM Cl3BPA significantly upregulated the phosphorylation of extracellular regulated protein kinases 1/2 (Erk1/2), the protein levels of GPER1 and the expression of the gper1 as well as the most target genes associated with mitogen-activated protein kinase (MAPK)/Erk1/2 pathways. Specific signal inhibitor experiments found that Cl3BPA activated KGG signals by activating the GPER1-mediated MAPK/Erk1/2 signaling pathway at the mRNA level. A docking test further confirmed the interactions between Cl3BPA and GPER1. The findings suggest that Cl3BPA might induce precocious puberty by increasing GnRH secretion together with KGG signaling upregulation, which is driven by GPER1-mediated signaling pathway. By comparison, ClxBPAs with fewer chlorine atoms had more obvious effects on the expression of proteins and partial genes related to KGG signals in GT1-7 cells.

Curcumin alleviates bisphenol AF-induced oxidative stress and apoptosis in caprine endometrial epithelial cells via the Nrf2 signaling pathway

Bisphenol AF (BPAF), a BPA-substitute, has been widely used in industrial compounds throughout the world. Several studies have shown that BPAF has endocrine interference and reproductive toxicity. However, the toxic effects of BPAF on pregnancy and placenta of goats are still unclear. Therefore, the objective of this study was to reveal the toxic effect of BPAF by using an in vitro culture model of caprine endometrial epithelial cells (EECs) and further attempted to alleviate the toxicity by curcumin pretreatment. The results showed that BPAF induces significant effects on EECs, including decreased cell viability and mitochondrial membrane potential (△ψm), elevating intracellular reactive oxygen species (ROS), promoting cell apoptosis through upregulating the expression of Bax, Cytochrome c, and downregulating the expression of Bcl-2. Meanwhile, BPAF induced dysregulation of oxidative stress by increasing the levels of malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) but decreasing the activities of superoxide dismutase (SOD). However, curcumin pretreatment could significantly attenuate BPAF-induced toxic effects in EECs. Further study revealed that BPAF treatment could activate mitogen-activated protein kinase (MAPK) pathway and nuclear factor-erythroid 2-related factor 2 (Nrf2) expression, but curcumin pretreatment significantly inhibited the activation of MAPK signal pathway and Nrf2 expression induced by BPAF. Overall, this study indicated that curcumin could prevent BPAF-induced EECs cytotoxicity, which provides a potential therapeutic strategy for female infertility associated with BPAF exposure.

N-Acetyl-L-Cysteine Ameliorates BPAF-Induced Porcine Sertoli Cell Apoptosis and Cell Cycle Arrest via Inhibiting the ROS Level

Bisphenol AF (BPAF) is a newly identified contaminant in the environment that has been linked to impairment of the male reproductive system. However, only a few studies have systematically studied the mechanisms underlying BPAF-induced toxicity in testicular Sertoli cells. Hence, this study primarily aims to explore the toxic mechanism of BPAF on the porcine Sertoli cell line (ST cells). The effects of various concentrations of BPAF on ST cell viability and cytotoxicity were evaluated using the Counting Kit-8 (CCK-8) assay. The results demonstrated that exposure to a high concentration of BPAF (above 50 μM) significantly inhibited ST cell viability due to marked cytotoxicity. Flow cytometry analysis further confirmed that BPAF facilitated apoptosis and induced cell cycle arrest in the G2/M phase. Moreover, BPAF exposure upregulated the expression of pro-apoptotic markers BAD and BAX while downregulating anti-apoptotic and cell proliferation markers BCL-2, PCNA, CDK2, and CDK4. BPAF exposure also resulted in elevated intracellular levels of reactive oxygen species (ROS) and malondialdehyde (MDA), alongside reduced activities of the antioxidants glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). Furthermore, the ROS scavenger N-acetyl-L-cysteine (NAC) effectively blocked BPAF-triggered apoptosis and cell cycle arrest. Therefore, this study suggests that BPAF induces apoptosis and cell cycle arrest in ST cells by activating ROS-mediated pathways. These findings enhance our understanding of BPAF's role in male reproductive toxicity and provide a foundation for future toxicological assessments.

Mechanisms of single herbs and herbal pairs in the treatment of mammary gland hyperplasia: An integrated review

Background

The pathogenesis of hyperplasia of mammary glands (HMG) is a complex process, involving multiple links and systems within the body. Current clinical research indicates that traditional Chinese medicine (TCM) demonstrates a significant therapeutic effect in treating HMG. Single herbs or herbal pairs (two herbs) are the basic units of preventing and treating HMG. It is of great significance to explore the mechanism of single herbs or herbal pairs in treating HMG for clarifying the mechanism of preventing HMG with TCM.

Purpose

This study aimed to review the literature, summarize the known mechanisms of single herbs and herbal pair therapy for treating hyperplasia of mammary glands (HMG), and elucidate the relevant substances involved within and outside the body during these treatments.

Study design

In this study, the action mechanism of single herbs or herbal pairs in treating HMG was selected as the research object. English articles were mainly selected and Chinese articles were supplemented. We conducted a literature search in PubMed, CNKI, WanFang Database, etc，including full-text studies published between January 1992 and December 31, 2022. The primary literature was carefully screened, and the mechanism of action was explored by logical analysis.

Methods

We conducted a literature review focusing on basic studies that explored the mechanisms underlying the effects of herbal treatments for mammary gland hyperplasia. The literature search was performed in PubMed, CNKI, and WanFang Database, covering full-text articles published from January 1992 to 31 December 2022, using various keywords (e.g., hyperplasia of mammary glands, single herb, herbal pair, effect, mechanism, inclusion criteria). Exclusion criteria were also set. We employed methods such as literature measurement, literature research, and content analysis to logically analyze, induce, and deduce the findings of the collected literature.

Results

This review reveals that several distinct mechanisms contribute to the beneficial effects of single herbs or herbal pairs on the recovery of mammary gland hyperplasia. Regarding hormone levels, Chinese herbs can decrease hormones such as Estradiol(E2) and Prolactin(PRL), increase Progesterone(P) levels, balance the E2/P ratio, reduce the expression of sex hormone receptors, and lessen the self-sensitivity of breast tissue under the influence of E2. Histologically, Chinese herbs can inhibit breast neovascularization and alleviate blood viscosity. At the cellular level, Chinese herbs can modulate the expression of apoptosis genes and proteins, decrease cell proliferation activity, and ultimately inhibit or even reverse breast hyperplasia. From a pharmacological perspective, Chinese herbs exhibit analgesic, anti-inflammatory, antioxidant, and immune-regulating properties.

Conclusion

The evidence in this review demonstrates the effectiveness of single herbs or herbal pairs in preventing and treating mammary gland hyperplasia, with precise underlying mechanisms.

In vitro and in silico assessment of GPER-dependent neurocytotoxicity of emerging bisphenols

To rapidly assess the toxicity of bisphenols (BPs) via the activation of G protein-coupled estrogen receptor (GPER), eight BPs action on GPER were evaluated by molecular docking and molecular dynamics (MD) simulation and then confirmed with IMR-32 cells. The target BPs significantly promoted the production of reactive oxygen species (ROS), reduced cell viability, activated the expression of apoptosis-related proteins and increased the apoptosis rate of IMR-32 cells. Intracellular Ca²⁺ level increased significantly after the treatments with bisphenol A (BPA), bisphenol E (BPE), bisphenol C (BPC) and bisphenol AP (BPAP), suggesting the activation of GPER. Moreover, the stable binding conformations between GPER and BPA, BPE, BPC and BPAP and their dynamic changes of GPER-BPs via MD simulation also suggest that these BPs may activate GPER. The interaction between bisphenol G/bisphenol P/bisphenol PH and GPER are weak, which is consistent with their low GPER activity in vitro. Notably, after the pretreatment of GPER antagonist, Ca²⁺ accumulation and ROS production induced by BPA, BPE, BPC and BPAP in IMR-32 cells were attenuated. Overall, MD simulation and in vitro results mutually verified the activation of GPER by BPs, and MD simulation can rapidly evaluate the neurocytotoxicity of BPs.

Reduced genotoxicity of lignin-derivable replacements to bisphenol A studied using in silico, in vitro, and in vivo methods

Bisguaiacols, lignin-derivable bisphenols, are considered promising and possibly safer alternatives to bisphenol A (BPA), but comprehensive toxicity investigations are needed to ensure safety. Most toxicity studies of BPA and its analogues have focused on potential estrogenic activity, and only limited toxicological data are available on other toxicity aspects, such as genotoxicity at low exposure levels. In this study, the genotoxicity of six lignin-derivable bisguaiacols with varying regioisomer contents and degrees of methoxy substitution was investigated using a multi-tiered method, consisting of in silico simulations, in vitro Ames tests, and in vivo comet tests. The toxicity estimation software tool, an application that predicts toxicity of chemicals using quantitative structure-activity relationships, calculated that the majority of the lignin-derivable bisguaiacols were non-mutagenic. These results were supported by Ames tests using five tester strains (TA98, TA100, TA102, TA1535, and TA1537) at concentrations ranging from 0.5 pmol/plate to 5 nmol/plate. The potential genotoxicity of bisguaiacols was further evaluated using in vivo comet testing in fetal chicken livers, and in addition to the standard alkaline comet assay, the formamidopyrimidine DNA glycosylase enzyme-modified comet assay was employed to investigate oxidative DNA damage in the liver samples. The oxidative stress analyses indicated that the majority of lignin-derivable analogues showed no signs of mutagenicity (mutagenic index < 1.5) or genotoxicity, in comparison to BPA and bisphenol F, likely due to the methoxy groups on the lignin-derivable aromatics. These findings reinforce the potential of lignin-derivable bisphenols as safer alternatives to BPA.

Adverse (geno)toxic effects of bisphenol A and its analogues in hepatic 3D cell model

Bisphenol A (BPA) is one of the most widely used and versatile chemical compounds in polymer additives and epoxy resins for manufacturing a range of products for human applications. It is known as endocrine disruptor, however, there is growing evidence that it is genotoxic. Because of its adverse effects, the European Union has restricted its use to protect human health and the environment. As a result, the industry has begun developing BPA analogues, but there are not yet sufficient toxicity data to claim that they are safe. We investigated the adverse toxic effects of BPA and its analogues (BPS, BPAP, BPAF, BPFL, and BPC) with emphasis on their cytotoxic and genotoxic activities after short (24-h) and prolonged (96-h) exposure in in vitro hepatic three-dimensional cell model developed from HepG2 cells. The results showed that BPFL and BPC (formed by an additional ring system) were the most cytotoxic analogues that affected cell viability, spheroid surface area and morphology, cell proliferation, and apoptotic cell death. BPA, BPAP, and BPAF induced DNA double-strand break formation (γH2AX assay), whereas BPAF and BPC increased the percentage of p-H3-positive cells, indicating their aneugenic activity. All BPs induced DNA single-strand break formation (comet assay), with BPAP (≥0.1 μM) being the most effective and BPA and BPC the least effective (≥1 μM) under conditions applied. The results indicate that not all of the analogues studied are safer alternatives to BPA and thus more in-depth research is urgently needed to adequately evaluate the risks of BPA analogues and assess their safety for humans.

Obesity as a Risk Factor for Breast Cancer-The Role of miRNA

Breast cancer (BC) is the most common cancer diagnosed among women in the world, with an ever-increasing incidence rate. Due to the dynamic increase in the occurrence of risk factors, including obesity and related metabolic disorders, the search for new regulatory mechanisms is necessary. This will help a complete understanding of the pathogenesis of breast cancer. The review presents the mechanisms of obesity as a factor that increases the risk of developing breast cancer and that even initiates the cancer process in the female population. The mechanisms presented in the paper relate to the inflammatory process resulting from current or progressive obesity leading to cell metabolism disorders and disturbed hormonal metabolism. All these processes are widely regulated by the action of microRNAs (miRNAs), which may constitute potential biomarkers influencing the pathogenesis of breast cancer and may be a promising target of anti-cancer therapies.

Bisphenol F blocks Leydig cell maturation and steroidogenesis in pubertal male rats through suppressing androgen receptor signaling and activating G-protein coupled estrogen receptor 1 (GPER1) signaling

Bisphenol F (BPF) is a new analog of bisphenol A (BPA). BPA has deleterious effects on the male reproductive system, but the effect of BPF has not been studied in detail. In this study we focus on the effect of BPF on Leydig cell maturation. Male Sprague-Dawley rats were gavaged with 0, 1, 10, or 100 mg/kg BPF from postnatal days 35-56. BPF significantly reduced serum testosterone levels and sperm count in cauda epididymis at dose ≥1 mg/kg. It significantly down-regulated the expression of steroidogenic enzymes, while increasing FSHR and SOX9 levels at 10 and 100 mg/kg. Further studies showed that BPF reduced NR3C4 expression in Leydig and Sertoli cells without affecting its levels in peritubular myoid cells. BPF markedly increased GPER1 in Leydig cells at 100 mg/kg, and it significantly reduced SIRT1 and PGC1α levels in the testes at 100 mg/kg. BPF significantly inhibited testosterone production by immature Leydig cells at 50 μM after 24 h of treatment, which was completely reversed by NR3C4 agonist 7α-methyl-19-nortestosterone and partially reversed by GPER1 antagonist G15 not by ESR1 antagonist ICI 182,780. In conclusion, BPF negatively affects Leydig cell maturation in pubertal male rats through NR3C4 antagonism and GPER1 agonism.

Generality and diversity on the kinetics, toxicity and DFT studies of sulfate radical-induced transformation of BPA and its analogues

The international campaign to ban bisphenol A (BPA) has resulted in increasing application of BPA substitutes. However, investigations have mainly been confined to the removal of single contaminant from the water, resulting in an inefficient burden. Furthermore, systematic study and synthetical discussion of bisphenol analogues (BPs) kinetics and transformation pathways were largely underemphasized. Chemical oxidation of BPA and four typical alternatives (i.e., bisphenol AF, bisphenol E, bisphenol F and bisphenol S) in a UV-activated persulfate system was examined in this study. The effects of persulfate (PS) dosage, pH and water matrix constituents (i.e., bicarbonate, chloride and natural organic matter) were comprehensively examined using a combination of laboratory experiments and mathematical modeling. According to our findings, the removal characteristics of different BPs employing SO₄•^--induced removal technology, including degradation mechanisms and influencing trends by water matrix, revealed similarly. The second order-rate constants of SO₄•^- reacting with BPs served as the main variables mediating the variation in degradation kinetics. Frontier molecular orbital theory and density functional theory suggested BPs molecules possessed the same susceptible positions to free radicals. In the UV-activated PS process, transformation pathways included hydroxylation, electron-transfer, substitution, and rearrangement triggered by ortho-cleavage, with certain intermediates exhibiting higher toxicity than the parent chemicals. The findings of this study provided valuable information to estimate potential environmental risks of using BPA alternatives.

Bisphenol A and its analogues in paired urine and house dust from South China and implications for children's exposure

Following the restriction of bisphenol A (BPA) in certain products, a number of bisphenol analogues (BPs) have been used as BPA replacements in different applications, raising environmental and health concerns. The present study determined a total of 13 bisphenol analogues in house dust and children urine from South China families (n = 46). Among all BPs, BPA, bisphenol S (BPS) and bisphenol F (BPF) were frequently detected in house dust, with concentrations ranging from 0.54 to 26.2 μg/g (median: 2.60 μg/g), 0.07-11.5 μg/g (median: 0.32 μg/g) and 0.02-2.4 μg/g (median: 0.29 μg/g), respectively. BPA (median: 2.43 ng/mL) was also the dominant BP in children urine samples, accounting for 75.2 ± 27.4% of the total concentrations of urinary BPs, followed by BPS (0.23 ng/mL), whereas BPF was only detected in less than 30% of urine samples. Children's daily intake of bisphenols through dust ingestion and total daily intakes were estimated based on the dust and urine concentrations, respectively. The estimated intake of BPA, BPS and BPF via house dust ingestion accounted for 9%, 12% and 38% of the total intakes predicted based on urinary concentrations, respectively, and exhibited very low exposure risks.

Bisphenol AF blocks Leydig cell regeneration from stem cells in male rats

Bisphenol A (BPA) is a ubiquitous environmental pollutant, mainly from the manufacture and use of plastics. The use of BPA is restricted, and its new analogs (including bisphenol AF, BPAF) are being produced to replace it. However, the effect of BPAF on the male reproductive system remains unclear. Here, we report the effect of BPAF on Leydig cell regeneration in rats. Leydig cells were eliminated by ethane dimethane sulfonate (EDS, i.p., 75 mg/kg) and the regeneration began 14 days after its treatment. We gavaged 0, 10, 100, and 200 mg/kg BPAF to rats on post-EDS day 7-28. BPAF significantly reduced serum testosterone and progesterone levels at ≧10 mg/kg. It markedly reduced serum levels of estradiol, luteinizing hormone, and follicle-stimulating hormone at 100 and 200 mg/kg. BPAF significantly reduced Leydig cell number at 200 mg/kg. BPAF significantly down-regulated the expression of Cyp17a1 at doses of 10 mg/kg and higher and the expression of Insl3, Star, Hsd17b3, Hsd11b1 in Leydig cells at 100 and 200 mg/kg, while it induced a significant up-regulation of Fshr, Dhh, and Sox9 in Sertoli cells at 200 mg/kg. BPAF induced oxidative stress and reduced the level of SOD2 at 200 mg/kg. It induced apoptosis and autophagy by increasing the levels of BAX, LC3B, and BECLIN1 and lowering the levels of BCL2 and p62 at 100 and 200 mg/kg. It induced autophagy possibly via decreasing the phosphorylation of AKT1 and mTOR. BPAF also significantly induced ROS production and apoptosis at a concentration of 10 μM, and reduced testosterone synthesis in rat R2C Leydig cells at a concentration of 10 μM in vitro, but did not affect cell viability after 24 h of treatment. In conclusion, BPAF is a novel endocrine disruptor, inhibiting the regeneration of Leydig cells.

Molecular Characterization of Membrane Steroid Receptors in Hormone-Sensitive Cancers

Cancer is one of the most common causes of death worldwide, and its development is a result of the complex interaction of genetic factors, environmental cues, and aging. Hormone-sensitive cancers depend on the action of one or more hormones for their development and progression. Sex steroids and corticosteroids can regulate different physiological functions, including metabolism, growth, and proliferation, through their interaction with specific nuclear receptors, that can transcriptionally regulate target genes via their genomic actions. Therefore, interference with hormones’ activities, e.g., deregulation of their production and downstream pathways or the exposition to exogenous hormone-active substances such as endocrine-disrupting chemicals (EDCs), can affect the regulation of their correlated pathways and trigger the neoplastic transformation. Although nuclear receptors account for most hormone-related biologic effects and their slow genomic responses are well-studied, less-known membrane receptors are emerging for their ability to mediate steroid hormones effects through the activation of rapid non-genomic responses also involved in the development of hormone-sensitive cancers. This review aims to collect pre-clinical and clinical data on these extranuclear receptors not only to draw attention to their emerging role in cancer development and progression but also to highlight their dual role as tumor microenvironment players and potential candidate drug targets.

Individual and combined effects of BPA, BPS and BPAF on the cardiomyocyte differentiation of embryonic stem cells

Exposure to many kinds of bisphenols (BPs) is common, and the effects of BP mixtures may differ from those of individual BPs. Therefore, evaluating combined exposure effects is necessary. Our study evaluated the individual and combined exposure effects of bisphenol A (BPA), bisphenol S (BPS) and bisphenol AF (BPAF) on embryonic development using an embryonic stem cell test (EST) and a concentration additive (CA) model at relatively high doses to uncover the interaction model of the three BPs. Environmentally relevant concentrations were then used to evaluate the possible effects of the individual and combined BPs at actual human exposure levels. Exposure to relatively high-dose BPA, BPS and BPAF inhibited embryonic stem cell differentiation into cardiomyocytes and exhibited weak embryo toxicity. Individually, BPA, BPS and BPAF inhibited endoderm, mesoderm and ectoderm marker expression but enhanced pluripotency marker expression. Combined exposure to BPs had an additive effect on cardiomyocyte differentiation and embryonic stem cell proliferation based on the CA model. Environmentally relevant individual or combined BP doses (10 ng/ml individual BPA, BPS and BPAF doses or 1 ng/ml and 10 ng/ml BP mixture doses) failed to cause oxidative stress, DNA damage or apoptosis changes in stem cell differentiation. The cardiomyocyte differentiation ratio also did not change significantly. Individual and combined exposure to environmentally relevant BP doses led to a significant increase in collagen expression. BPAF and the combination of BPs increased the type 1 collagen level, while the combination also increased the type 3 collagen level, which may be related to p38 pathway activation. The p38 pathway inhibitor SB203580 inhibited the increase in collagen during cardiomyocyte differentiation caused by low-dose BPs. These results suggest that relatively high-dose BPs in combination have an additive effect on cardiomyocyte differentiation. Low-dose BPs individually and in combination may affect cardiomyocyte collagen through the p38 pathway.

Schisandrol A Exhibits Estrogenic Activity via Estrogen Receptor α-Dependent Signaling Pathway in Estrogen Receptor-Positive Breast Cancer Cells

The aim of this study was to examine the estrogen-like effects of gentiopicroside, macelignan, γ-mangostin, and three lignans (schisandrol A, schisandrol B, and schisandrin C), and their possible mechanism of action. Their effects on the proliferation of the estrogen receptor (ER)-positive breast cancer cell line (MCF-7) were evaluated using Ez-Cytox reagents. The expression of extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K), AKT, and estrogen receptor α (ERα) was measured by performing Western blot analysis. 17β-estradiol (E2), also known as estradiol, is an estrogen steroid and was used as a positive control. ICI 182,780 (ICI), an ER antagonist, was used to block the ER function. Our results showed that, except for gentiopicroside, all the compounds promoted proliferation of MCF-7 cells, with schisandrol A being the most effective; this effect was better than that of E2 and was mitigated by ICI. Consistently, the expression of ERK, PI3K, AKT, and ERα increased following treatment with schisandrol A; this effect was slightly better than that of E2 and was mitigated by ICI. Taken together, the ERα induction via the PI3K/AKT and ERK signaling pathways may be a potential mechanism underlying the estrogen-like effects of schisandrol A. This study provides an experimental basis for the application of schisandrol A as a phytoestrogen for the prevention of menopausal symptoms.

Molecular mechanism study of BPAF-induced proliferation of ERα-negative SKBR-3 human breast cancer cells in vitro/in vivo

Bisphenol AF (BPAF) is a known estrogen disruptor of the ERα pathway. The aim of the present study was to characterize the proliferation effects of BPAF on ERα-negative SKBR-3 breast cancer cells with mechanistic insights. BPAF at low concentrations (0.001-0.1 μM) significantly induced the proliferation of SKBR-3 cells. In a SKBR-3 tumor model in BALB/c nude mice, BPAF at 100 mg/kg body weight/day also significantly promoted the growth of SKBR-3 tumors. Low concentrations of BPAF markedly increased the expression of G protein-coupled estrogen receptor (GPER1), c-Myc, CyclinD1 and c-Fos proteins, and enhanced phosphorylation of extracellular signal-regulated kinase (Erk) and protein kinase B (Akt) in SKBR-3 cells. Further, BPAF significantly upregulated mRNA levels of related target genes in SKBR-3 cells and SKBR-3 tumor tissues in nude mice. The GPER1 inhibitor G15 and phosphatidylinositide 3-kinase (PI3K) inhibitor wortmannin (WM) inhibited phosphorylation of Erk and Akt. The specific signal inhibitors also markedly decreased the expression of target genes and weakened the cell proliferation induced by low-concentration BPAF. The findings showed that GPER1 could independently regulate BPAF-induced proliferation of SKBR-3 cells without requiring ERα. These results provide mechanistic insights into the effects of BPAF regarding ERα-negative human breast cancer development.

Environmental Estrogens and Their Biological Effects through GPER Mediated Signal Pathways

Many environmental chemicals have been found to exert estrogenic effects in cells and experimental animals by activating nuclear receptors such as estrogen receptors and estrogen-related receptors. These compounds include bisphenols, pesticides, polybrominated diphenyl ethers (PBDEs), organophosphate flame retardants, phthalates and metalloestrogens. G protein-coupled estrogen receptor (GPER) exists widely in numerous cells/tissues of human and other vertebrates. A number of studies have demonstrated that GPER plays a vital role in mediating the estrogenic effects of environmental pollutants. Even at very low concentrations, these chemicals may activate GPER pathways, thus affect many aspects of cellular functions including proliferation, metastasis and apoptosis, resulting in cancer progression, cardiovascular disorders, and reproductive dysfunction. This review summarized the environmental occurrence and human exposure levels of these pollutants, and integrated current experimental evidence toward revealing the underlying mechanisms of pollutant-induced cellular dysfunction via GPER. The GPER mediated rapid non-genomic actions play an important role in the process leading to the adverse effects observed in experimental animals and even in human beings.

Insight into the mechanism of tetrachlorobisphenol A (TCBPA)-induced proliferation of breast cancer cells by GPER-mediated signaling pathways

Tetrachlorobisphenol A (TCBPA), a chlorinated derivative of bisphenol A, is an endocrine disruptor based on interaction with nuclear estrogen receptor alpha (ERα). However, there is only limited data on the mechanisms through which TCBPA-associated estrogenic activity is related to the membrane G protein-coupled estrogen receptor (GPER) pathway. In this study, three human breast cancer cell lines-MCF-7, SKBR3, and MDA-MB-231 cells were used to evaluate whether, as well as how, TCBPA at concentration range of 0.001-50 μM affect cell proliferation. The role of GPER signaling in TCBPA-induced cell proliferation was studied by analyzing the protein expression and mRNA levels of relevant signal targets. The results showed that low concentrations of TCBPA significantly induced the proliferation of MCF-7, SKBR3, and MDA-MB-231 cells, with MCF-7 cells being the most sensitive to TCBPA exposure. Low-concentration TCBPA also upregulated the expression of GPER, CyclinD1, c-Myc, and c-Fos proteins, as well as increased the phosphorylation of extracellular signal-regulated-kinase 1/2 (Erk1/2) and protein kinase B (Akt). Additionally, the mRNA levels of genes associated with estrogen signaling pathways also increased upon exposure to TCBPA. However, the phosphorylation of Erk1/2 and Akt decreased when the cells were treated with GPER inhibitor G15 and phosphatidylinositide 3-kinase (PI3K) inhibitor wortmannin (WM) prior to TCBPA exposure. Besides, the increased proliferation of breast cancer cells induced by TCBPA were also inhibited. In ERα-positive MCF-7 cells, TCBPA also upregulated ERα expression, and ERα was found to interact with GPER-mediated signaling. The results indicate that GPER activates the PI3K/Akt and Erk1/2 signal cascades to drive the cell proliferation observed for low concentrations of TCBPA. The presented results suggest a new mechanism by which TCBPA exerts estrogenic action in breast cancer cells, namely, GPER signaling in an ERα-independent manner, and also highlights the potential risks to human health of the usage of TCBPA.

The proliferation effects of fluoxetine and amitriptyline on human breast cancer cells and the underlying molecular mechanisms

Some studies have suggested possible estrogen actions for antidepressants such as fluoxetine. However, the specific molecular mechanisms remain unclear. In this study, the molecular mechanism of fluoxetine-induced the proliferation of breast cancer SKBR3 and MCF-7 cells was evaluated by detecting ERα and GPR30-mediated ERK and PI3K/AKT signals. We found that low concentrations of fluoxetine upregulated the expression of GPR30, ERα, CyclinD1, and C-MYC proteins, as well as elevated the phosphorylation of ERK and AKT. The phosphorylation of ERK and AKT decreased when the cells were pretreated with ERα inhibitor ICI, GPR30 inhibitor G15, and PI3K inhibitor WM prior to fluoxetine exposure. The addition of these inhibitors also attenuated the fluoxetine-induced cell proliferation. These findings indicated that fluoxetine activated the PI3K/AKT and ERK signaling cascades via GPR30 to derive the cell proliferation. It suggests that fluoxetine has the potential to exert estrogen actions via GPR30.

A targeted review on fate, occurrence, risk and health implications of bisphenol analogues

Due to its widespread applications and its ubiquitous occurrence in the environment, bisphenol A (BPA) and its alternatives have gained increasing attention, especially in terms of human safety. Like BPA, alternatives such as bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF) have also been identified to be endocrine-disrupting chemicals (EDCs). Hence, in this study, we reviewed the literature of BPA and its alternatives mainly published between the period 2018-2020, including their occurrences in the environment, human exposure, and adverse health effects. The review shows that bisphenols are prevalent in the environment with BPA, BPS, and BPF being the most ubiquitous in the environment worldwide, though BPA remains the most abundant bisphenol. However, the levels of BPS and BPF in different environmental media have been constantly increasing and their fates and health risks are being evaluated. The studies show that humans and animals are exposed to bisphenols in many different ways through inhalation and ingestion and the exposure can have serious health effects. Urinary bisphenols (BPs) levels were frequently reported to be positively associated with different health problems such as cancer, infertility, cardiovascular diseases, diabetes and neurodegenerative diseases. Our literature study also shows that BPs generate reactive oxygen species and disrupt various signalling pathways, which could lead to the development of chronic diseases. Activated carbon-based and chitosan-based sorbents have been widely utilized in the removal of BPA in aqueous solutions. In addition, enzymes and microorganisms have also been getting much attention due to their high removal efficiencies.

Endocrine-Disrupting Chemicals' (EDCs) Effects on Tumour Microenvironment and Cancer Progression: Emerging Contribution of RACK1

Endocrine disruptors (EDCs) can display estrogenic and androgenic effects, and their exposure has been linked to increased cancer risk. EDCs have been shown to directly affect cancer cell regulation and progression, but their influence on tumour microenvironment is still not completely elucidated. In this context, the signalling hub protein RACK1 (Receptor for Activated C Kinase 1) could represent a nexus between cancer and the immune system due to its roles in cancer progression and innate immune activation. Since RACK1 is a relevant EDCs target that responds to steroid-active compounds, it could be considered a molecular bridge between the endocrine-regulated tumour microenvironment and the innate immune system. We provide an analysis of immunomodulatory and cancer-promoting effects of different EDCs in shaping tumour microenvironment, with a final focus on the scaffold protein RACK1 as a pivotal molecular player due to its dual role in immune and cancer contexts.

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.

G protein-coupled estrogen receptor-1: homology modeling approaches and application in screening new GPER-1 modulators

G protein-coupled receptors (GPCRs) belong to the largest family of protein targets comprising over 800 members in which at least 500 members are the therapeutic targets. Among the GPCRs, G protein-coupled estrogen receptor-1 (GPER-1) has shown to have the ability in estrogen signaling. As GPER-1 plays a critical role in several physiological responses, GPER-1 has been considered as a potential therapeutic target to treat estrogen-based cancers and other non-communicable diseases. However, the progress in the understanding of GPER-1 structure and function is relatively slow due to the availability of a only a few selective GPER-1 modulators. As with many GPCRs, the X-ray crystal structure of GPER-1 is yet to be resolved and thus has led the researchers to search for new GPER-1 modulators using homology models of GPER-1. In this review, we aim to summarize various approaches used in the generation of GPER-1 homology model and their applications that have resulted in new GPER-1 ligands.

Bisphenol A-Induced Cell Proliferation and Mitochondrial Oxidative Stress Are Diminished via Modulation of TRPV1 Channel in Estrogen Positive Breast Cancer Cell by Selenium Treatment

Cancer cell proliferation and apoptosis are induced by overload Ca²⁺ entry. Transient receptor potential vanilloid 1 (TRPV1) as a Ca²⁺ permeable cation channel is activated by capsaicin and reactive oxygen species (ROS), although it is blocked by capsazepine and sodium selenite (Na-Se). Bisphenol A (BPA) induces estrogenic action and further stimulates the proliferation of estrogen receptor positive MCF-7 cell through excessive production ROS and Ca²⁺ influx. However, whether or not Na-Se can influence BPA-induced oxidative stress and apoptosis through modulation of TRPV1 in breast cancer cells has not drawn much attention. The MCF-7 and MDA-MB-231 breast cancer cells were divided into four treatment groups as control, Na-Se (1 μM for 2 h), and BPA (0.1 mM for 24 h) and BPA + Na-Se. The Na-Se reduced BPA-induced increase of cell number, mitochondria oxidative stress, and TRPV1 channel activity modulation of MCF-7 cells, which was proved by the suppression of cell viability, excessive ROS production, mitochondrial membrane depolarization, lipid peroxidation, early apoptosis (Annexin-V), late apoptosis (propidium iodide) and upregulation of reduced glutathione, glutathione peroxidase, and cell death (propidium iodide/Hoechst rate). The similar effects of Na-Se were observed in the MCF-7 cells by capsazepine treatment. However, the effects of BPA were not observed in the MDA-MB-231 breast cancer cells. In conclusion, cell proliferative and oxidant effects of BPA were increased by activation of TRPV1, but its action on the values was decreased by the Na-Se treatment. The results may be a good set of preliminary data for designing animal studies on estrogenic effect of bisphenol A and antiestrogenic of selenium.

Quercetin exerts bidirectional regulation effects on the efficacy of tamoxifen in estrogen receptor-positive breast cancer therapy: An in vitro study

Tamoxifen was widely applied in the therapy of estrogen receptor (ER)-positive breast cancer. With the purpose of determining the potential impacts of quercetin on its effectiveness, MCF-7 cells were selected as the in vitro model and several cellular biological behaviors (ie, cell proliferation, migration, invasion, cycle, apoptosis, and oxidative stress) were investigated. As results, quercetin showed contrasting dose-response to cellular behaviors dependent on the ROS-regulated p53 signaling pathways. In detail, quercetin promoted cell proliferation and inhibited cell apoptosis at low concentrations, whereas high-concentration resulted in apoptosis induction. Moreover, quercetin at a low concentration significantly inhibited tamoxifen-induced antiproliferation in MCF-7 cells, whereas high concentrations enhanced cell apoptosis in a synergetic manner. The real-time quantitative polymerase chain reaction analysis further implied that quercetin exerted its dual roles in tamoxifen-induced antiproliferative effects by regulated the gene expression involved in cell metastasis, cycle, and apoptosis through the ER pathways. Our present study provides a considerable support to the combination of quercetin and tamoxifen on human ER-positive breast carcinoma management.

Transcriptomic analysis of bisphenol AF on early growth and development of zebrafish (Danio rerio) larvae

Bisphenol AF (BPAF), an alternative to bisphenol A, is widely detected in aquatic environments. Owing to health concerns, the toxic effects of BPAF on organisms are drawing attention. The present study aims to evaluate the toxicity of BPAF, combining the results of omics techniques and experiment. Employing transcriptome sequencing (RNA-seq), we obtained 391, 648, 512, and 545 differentially expressed genes (DEGs) in 0.1, 1, 10, and 100 μg/L BPAF-exposed zebrafish larvae, respectively. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealed the early development, stimulus-response, and MAPK signaling pathway were significantly affected by BPAF. In addition, five hub genes (fgf3, fgf4, map2k1, myca, and casp3b) were highlighted as the key genes in MAPK signaling pathway using the protein-protein interaction network. Therefore, the RNA-seq results showed that early development and stimulus-response were the main processes affected by BPAF, which was consistent with our morphological and pathological results. The hatching rate of zebrafish embryos in 1 and 10 μg/L BPAF groups was significantly inhibited, and the oxidative stress indexes, including the level of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and lipid peroxidation (LPO), were significantly increased by the 100 μg/L BPAF treatment. Moreover, the activity of alkaline phosphatase (AKP) was significantly decreased in all BPAF exposure groups. In conclusion, exposure to BPAF at environmental relevant concentrations affected the early development and immune system of zebrafish larvae by modulating MAPK signaling pathway, and our results provide solid evidence for the future studies on the toxicity of bisphenols.

The Interaction Test of Binary Mixtures of Endocrine-Disrupting Chemicals Using In Vitro Bioassays

Typical environmental endocrine-disrupting chemicals (EDCs) such as estradiol valerate (EV), diethylstilbestrol (DES), di-2-ethylhexyl phthalate (DEHP), mono-2-ethylhexyl phthalate (MEHP), and bisphenol A (BPA) have a strong reproductive and developmental toxicity at low concentrations. However, information on their joint toxicity is scarce. In this study, we evaluated the combined effects of EV and other four EDCs (DES, DEHP, MEHP, and BPA) on the human breast MCF-7 cells by detecting the cell proliferation, intracellular reactive oxygen species (ROS) levels, and estrogen receptor alpha (ERα) protein expression using equal concentration ratio method. The results showed that, after exposure for 24, 48, and 72 h, single EV, DES, and BPA can promote the proliferation of MCF-7 human breast cancer cells, and EV has the strongest effect in inducing cell proliferation. DEHP and MEHP cannot induce MCF-7 cell proliferation for all exposure time, while cell proliferation induced by EV was significantly attenuated by DES, BPA, DEHP, and MEHP when they mixed with EV. For intracellular ROS, single EV, BPA, DES, DEHP, and MEHP elevated intracellular ROS levels for different exposure time. Similar to the cell proliferation, DES and BPA decreased intracellular ROS levels induced by EV when they mixed with EV for 24 h. EV, DES, and BPA exposed alone or combined with EV upregulated the ERα protein expression. However, DEHP and MEHP exposed alone or combined with EV had no effect on ERα protein expression, indicating that DEHP or MEHP could attenuate ERα protein expression upregulated by EV. These results showed that the joint toxicity of binary mixtures of EV and other EDCs do not interact in a synergistic fashion in inducing cell proliferation, intracellular ROS levels, and ERα protein expression. These findings have important implications in the human risk assessments of EV mixed with other EDCs in the environment.

Occurrence of bisphenol A and its alternatives in paired urine and indoor dust from Chinese university students: Implications for human exposure

Bisphenol analogs (BPs), as the industrial chemicals, are widely used in consumer products. Limited information exists regarding human exposure to BPs in university students in China. In this study, we detected concentrations of seven BPs, namely bisphenol A (BPA), bisphenol AF (BPAF), bisphenol P (BPP), bisphenol AP (BPAP), bisphenol Z (BPZ), bisphenol S (BPS), and bisphenol F (BPF), in paired urine (n = 160) and indoor dust samples (n = 40) from university students in South China. High detection rates and levels (median) was found in BPA in paired urine (99%, 3.57 ng/mL) and indoor dust (80%, 2.98 μg/g) samples, followed by BPS (88%, 0.24 ng/mL; 78%, 0.22 μg/g). These findings suggest that BPA remains the major BPs used in consumer products. A positive relationship between urinary ∑BPs (sum of six BPs) concentration and indoor dust was observed (r = 0.444, p < 0.01), indicated that exposure to non-dietary BPs may also be significant to human exposure. The median EDI_urine values (ng/kg bw/day) of ∑BPs in males (119.6) were relatively higher than (p < 0.05) those in females (84.6). By contrast, the median EDI_dust of BPs (except for BPAF) in dust form female dormitories were slightly higher than that in dust from male dormitories. Notably, BPF was the most ingested from indoor dust (dormitory dust). This study is the first time to document the occurrence of BPs in paired urine and indoor dust in university students from China.

4-Hexylresorcinol Exhibits Different Characteristics to Estrogen

4-Hexylresorcinol (4HR) has been used as a food additive and antiseptic. The aim of this study was to evaluate whether the application of 4HR in breast cancer cells and ovariectomized rats showed estrogen-like effects. MCF-7 and SK-BR-3 cells were treated by solvent, 1–100 µM bisphenol-A (BPA), or 1–100 µM 4HR, respectively. 3-(4, 5-Dimethylthiazole-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay and Western blot for extracellular signal-regulated kinase-1/-2 (ERK1/2), phosphorylated ERK1/2 (p-ERK1/2), estrogen receptor-α (ERα), and ERβ were done. As an in vivo study, ovariectomized rats (n = 15) received solvent, 125 mg/kg of 4HR, or 10 µg of 17-β estradiol via daily subcutaneous injection for 7 days. Blood samples were obtained for evaluation of prolactin levels. Pituitary glands and uteruses were biopsied for histological evaluation and Western blot analysis. Compared with the control group, the application of 4HR decreased the proliferation of MCF-7 and SK-BR-3 cells, while the application of BPA increased (p < 0.05). The application of BPA increased the expression of ERα, ERβ, and p-ERK1/2, but 4HR did not change the expression of ERα, ERβ, or p-ERK1/2 in MCF-7 cells. In an animal model, the 4HR group showed similar levels of ERα, ERβ, and prolactin expression in the pituitary gland compared to the solvent only group, while the estradiol group showed higher levels. Serum prolactin levels were similar between the 4HR and solvent only groups. Taken together, 1–100 µM 4HR did not show BPA-like behavior in MCF-7 cells, and 125 mg/kg of 4HR daily subcutaneous injection for 7 days did not demonstrate estradiol-like effects in ovariectomized rats. Collectively, 4HR has no estrogen-like effects on both ERα-positive cells and estrogen-deficient rat models.

Bisphenol A Exposure Enhances Endometrial Stromal Cell Invasion and Has a Positive Association with Peritoneal Endometriosis

Results of previous epidemiology studies on BPA exposure and endometriosis (EMs) risk were inconsistent, and were limited by inappropriate control selection, incorrect BPA detection method, and the generalization of different subtypes of EMs. Upregulated matrix metalloproteinase (MMP) 2 and MMP9 are involved in the development of EMs. We conducted a case-control study among 120 EMs patients and 100 healthy women to evaluate the relationships between BPA exposure and MMP2, MMP9 expressions, and the risk of EMs subtypes. Besides, we used human endometrial stromal cell lines (HESCs) to investigate the underlying mechanisms. Creatinine-adjusted urinary BPA concentrations were positively correlated with serum MMP2, MMP9 levels, and the risk of peritoneal EMs (third vs lowest quartile: OR 4.92, 95% CI 1.47, 16.50; fourth versus lowest quartile: OR 3.70, 95% CI 1.07, 12.74, P_trend = 0.030). The risk of peritoneal EMs increased approximately tenfold when creatinine-adjusted urinary BPA concentration was 2 μg/g. In vitro study found that BPA exposure increased MMP2, MMP9 expressions in a dose-dependent manner. The effects of BPA on HESCs could be blocked by G protein-coupled estrogen receptor (GPER) inhibitor or mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) inhibitor. This study provides evidence that BPA exposure promotes peritoneal EMs, and raises a concern about the potential toxicity of BPA on the female reproductive system.

Bisphenols as a Legacy Pollutant, and Their Effects on Organ Vulnerability

Bisphenols are widely used in the synthesis of polycarbonate plastics, epoxy resins, and thermal paper, which are used in manufacturing items of daily use. Packaged foods and drinks are the main sources of exposure to bisphenols. These chemicals affect humans and animals by disrupting the estrogen, androgen, progesterone, thyroid, and aryl hydrocarbon receptor functions. Bisphenols exert numerous harmful effects because of their interaction with receptors, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial dysfunction, and cell signal alterations. Both cohort and case-control studies have determined an association between bisphenol exposure and increased risk of cardiovascular diseases, neurological disorders, reproductive abnormalities, obesity, and diabetes. Prenatal exposure to bisphenols results in developmental disorders in animals. These chemicals also affect the immune cells and play a significant role in initiating the inflammatory response. Exposure to bisphenols exhibit age, gender, and dose-dependent effects. Even at low concentrations, bisphenols exert toxicity, and hence deserve a critical assessment of their uses. Since bisphenols have a global influence on human health, the need to discover the underlying pathways involved in all disease conditions is essential. Furthermore, it is important to promote the use of alternatives for bisphenols, thereby restricting their uses.

17β-estradiol at low concentrations attenuates the efficacy of tamoxifen in breast cancer therapy

Tamoxifen has been applied widely in the treatment of estrogen receptor (ER)-positive breast cancer. The impact of low concentrations of 17β-estradiol (E2) (a pervasive environmental pollutant) on its effectiveness was studied in vitro using an MCF-7 cell line. Cell proliferation, migration, invasion, and apoptosis were studied along with cell cycle progression, reactive oxygen species generation and mitochondrial membrane potentials repression. The signaling pathways involved were identified. Typical concentrations of E2 in the environment (10^-10 to 10^-8 M) were observed to promote cell growth and protect MCF-7 cells from tamoxifen's cytotoxicity. Cell migration, invasion, cell cycle progression and apoptosis all involved in reducing tamoxifen's cytotoxicity. E2 at environmental concentrations induced PI3K/Akt and MAPK/ERK signal transduction through the estrogen receptor pathways to affect cell proliferation. Taken together, the results explain how E2 in the environment may attenuate the efficacy of tamoxifen in ER-positive breast cancer therapy. They provide considerable support for E2's adverse effects on human health and cancer management.

Girdin knockdown promotes apoptosis in colorectal cancer via miR-29c-3p/Girdin axis

Background

In recent years, the incidence and mortality of colorectal cancer (CRC) have increased year by year among young people. Increased levels of Girdin expression predict a poor prognosis of CRC, which presents a serious threat to human health globally. Herein, we investigated the role of Girdin in CRC and explored the underlying mechanisms in CRC.

Methods

The expression of Girdin was detected in human specimens. HCT116 cells with stably expressing or knock-out Girdin protein were successfully constructed to observe the biological function of gene. Protein expression was determined by immunohistochemistry, immunofluorescence and western blot.

Results

Clinically, overexpression of Girdin was observed in the tumor tissue and poor prognosis of CRC patients. Gain-of-function and loss-of-function assays showed that Girdin promoted CRC cell proliferation in vitro. Mechanistically, Girdin knock-down significantly enhanced apoptosis, the mitochondrial membrane potential dropped, and the reactive oxygen species increased greatly. Last but not least, we analyzed the TargetScan dataset and found that Girdin was a regulated target of hsa-miR-29c-3p in CRC. Luciferase reporter assay was used to verify the interaction between hsa-miR-29c-3p and the 3’UTR of Girdin.

Conclusions

Our findings suggest that Girdin has a crucial role in CRC progression via miR-29c-3p/Girdin axis, highlighting Girdin as a therapeutic target for CRC.

Friend or foe, the role of EGR-1 in cancer

Early growth response-1 (EGR-1), also termed NEFI-A and Krox-24, as a multi-domain protein is implicated in several vital physiological processes, including development, metabolism, cell growth and proliferation. Previous studies have implied that EGR-1 was producing in response to the tissue injury, immune response and fibrosis. Meanwhile, emerging studies stressed the pronounced correlation of EGR-1 and human cancers. Nevertheless, the intricate mechanisms of cancer-reduce EGR-1 alteration still poorly characterized. In the review, we evaluated the effects of EGR-1 in tumor cell proliferation, apoptosis, migration, invasion and tumor microenvironment, and then, we dwell on the intricate signaling pathways that EGR-1 involved in. The aberrantly expressed of EGR-1 in cancers are expected to provide a new cancer therapy strategy or a new marker for assessing treatment efficacy.

Rafoxanide promotes apoptosis and autophagy of gastric cancer cells by suppressing PI3K /Akt/mTOR pathway

Rafoxanide is commonly used as anti-helminthic medicine in veterinary medicine, a main compound of salicylanilide. Previous studies have reported that rafoxanide, as an inhibitor of BRAF V600E mutant protein, inhibits the growth of colorectal cancer, multiple myeloma, and skin cancer. However, its therapeutic effect on gastric cancer (GC) and the potential mechanism has not been investigated. Here, we have found that rafoxanide inhibited the proliferation of GC cells in vitro, arrested the cell cycle in the G0/G1 phase, and promoted apoptosis and autophagy in GC cells. Treatment with specific autophagy inhibitor 3-methyladenine drastically inhibited the apoptotic cell death effect by suppressing the switch from autophagy to apoptosis. Mechanistically, we found that rafoxanide inhibited the growth of GC cells in vitro by inhibiting the activity of the PI3K/Akt/mTOR signaling pathway. This process induced autophagy, which essentially resulted in the apoptosis of GC cells. Results from subcutaneous implanted tumor models in nude mice also indicated that rafoxanide inhibited the growth of GC cells in vivo. Taken together, our findings revealed that rafoxanide inhibited the growth of GC cells both in vitro and vivo, indicating a potential drug candidate for the treatment of GC.

Estrogen receptor subtype agonist activation in human cutaneous squamous cell carcinoma cells modulates expression of CD55 and Cyclin D1

Clinical studies indicate gender bias in cutaneous squamous cell carcinoma (cSCC) incidence with worse prognosis observed in males than in females, suggesting estrogen-mediated protection. In contrast, recent clinical population studies show risk of cSCC by use of oral contraceptives, thus raising controversy. However, animal studies indicate a protective role of estrogen and estrogen receptor (ER)s in cSCC. Currently we have a poor understanding of ERs that are expressed in human cSCC cells and their possible role in malignant transformation. The focus of current study was to determine ER subtype specific expression on cSCC A431 cells and investigate if ER agonist based activation modulates tumor markers CD55 and Cyclin D1 in the cells. ERα, ERβ and G protein-coupled receptor (GPR30) subtype expression at mRNA and protein level was determined in human cSCC A431 cells by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting, respectively. The localization of ER subtypes was determined by confocal microscopy. ER subtype agonist based activation on A431 cells was performed to investigate their role in modulating mRNA and protein expression of tumor markers CD55 and Cyclin D1. A431 cells differentially expressed all three ER subtypes- ERα, ERβ and GPR30 with GPR30 expression being the highest. Confocal studies confirmed that all three ER subtypes were expressed in the cytoplasm and ERα and ERβ lacked nuclear expression. Agonist based activation of both ERα and GPR30 significantly upregulated Cyclin D1 and CD55 expression. Blocking of GPR30 led to significantly downregulation of both Cyclin D1 and CD55 expression. In contrast to ERα and GPR30, ERβ activation significantly downregulated CD55 expression. Taken together, here we demonstrate for the first time that all three ERs- ERα, ERβ and GPR30 are expressed in human A431 cSCC cells and further ER agonist based activation modulates the expression of tumor markers CD55 and Cyclin D1.

Mechanism of Rapid Nuclear Factor-E2-Related Factor 2 (Nrf2) Activation via Membrane-Associated Estrogen Receptors: Roles of NADPH Oxidase 1, Neutral Sphingomyelinase 2 and Epidermal Growth Factor Receptor (EGFR)

Membrane-associated estrogen receptors (ER)-α36 and G protein-coupled estrogen receptor (GPER) play important roles in the estrogen’s rapid non-genomic actions including stimulation of cell proliferation. Estrogen via these receptors induces rapid activation of transcription factor nuclear factor-E2-related factor 2 (Nrf2), a master regulator of detoxification and antioxidant systems, playing a key role in the metabolic reprogramming to support cell proliferation. This review highlights the possible mechanism underlying rapid Nrf2 activation via membrane-associated estrogen receptors by estrogen and phytoestrogens. Stimulation of ER-α36-GPER signaling complex rapidly induces Src-mediated transactivation of epidermal growth factor receptor (EGFR) leading to a kinase-mediated signaling cascade. We propose a novel hypothesis that ER-α36-GPER signaling initially induces rapid and temporal activation of NADPH oxidase 1 to generate superoxide, which subsequently activates redox-sensitive neutral sphingomyelinase 2 generating the lipid signaling mediator ceramide. Generation of ceramide is required for Ras activation and ceramide-protein kinase C ζ-casein kinase 2 (CK2) signaling. Notably, CK2 enhances chaperone activity of the Cdc37-Hsp90 complex supporting activation of various signaling kinases including Src, Raf and Akt (protein kinase B). Activation of Nrf2 may be induced by cooperation of two signaling pathways, (i) Nrf2 stabilization by direct phosphorylation by CK2 and (ii) EGFR-Ras-PI 3 kinase (PI3K)-Akt axis which inhibits glycogen synthase kinase 3β leading to enhanced nuclear transport and stability of Nrf2.