Association of organophosphate flame retardants exposure with liver function and the contrasting mediating roles of inflammatory and oxidative stress pathways

Organophosphate flame retardants (OPFRs) have been widely used as alternatives to traditional halogenated flame retardants, resulting in their pervasive environmental presence and significant human exposure. While animal studies using high doses of individual OPFRs have demonstrated hepatotoxicity, evidence of hepatic effects from chronic and low-dose exposure to OPFRs in humans is scarce, and the underlying mechanisms remain largely unknown. In this study, we evaluated the association between urinary metabolites of OPFRs (mOPFRs) and liver function biomarkers in a population aged 1-79 years from the Guangzhou Human Biomonitoring Program. Urinary concentrations of diphenyl phosphate exhibited a significant decreasing trend with increasing age across four age groups (≤12, 13-17, 17-59, ≥60 years), while bis(1-chloro-2-propyl) phosphate concentrations showed a significant positive association with age. Urinary mOPFRs were positively associated with alanine aminotransferase, gamma-glutamyl transferase, and aspartate aminotransferase, and negatively associated with indirect bilirubin levels. Urinary mOPFRs were significantly correlated with total bilirubin, which was consistent with that observed in the National Health and Nutrition Examination Survey database, while other associations were inconsistent. Moreover, we evaluated the roles of inflammatory and oxidative stress markers in the association between urinary mOPFRs and liver function biomarkers by mediation analysis. The results demonstrated that the mediation effects of inflammatory markers were consistent with the total and direct effects of mOPFRs on liver function biomarkers, whereas the mediation effects of oxidative stress markers were discrepant. Inflammation likely exacerbates the adverse effects of OPFRs on liver function, while oxidative stress may play a protective role. We further searched the comparative toxicogenomics database for genes associated with OPFRs and liver function biomarkers to understand the potential regulatory mechanisms.

Organophosphate flame retardants tris (2-butoxyethyl) phosphate (TBEP) and tris (2-chloroethyl) phosphate (TCEP) disrupt human motor neuron development by differentially affecting their survival and differentiation

Mounting evidence in animal experiments proves that early life stage exposure to organophosphate flame retardants (OPFRs) affects the locomotor behavior and changes the transcriptions of central nervous system genes. Unfortunately, their effect on human motor neuron (MN) development, which is necessary for body locomotion and survival, has not yet characterized. Here, we utilized a spinal cord MN differentiation model from human embryonic stem cells (ESCs) and adopted this model to test the effects of two typical OPFRs tris (2-butoxyethyl) phosphate (TBEP) and tris (2-chloroethyl) phosphate (TCEP), on MN development and the possible mechanisms underlying. Our findings revealed TBEP exerted a much more inhibitory effect on MN survival, while TCEP exhibited a stronger stimulatory effect on ESCs differentiation into MN, and thus TBEP exhibited a stronger inhibition on MN development than TCEP. RNA sequencing analysis identified TBEP and TCEP inhibited MN survival mainly by disrupting extracellular matrix (ECM)-receptor interaction. Focusing on the pathway guided MN differentiation, we found both TBEP and TCEP activated BMP signaling, whereas TCEP simultaneously downregulated Wnt signaling. Collectively, this is the first study demonstrated TBEP and TCEP disrupted human MN development by affecting their survival and differentiation, thereby raising concern about their potential harm in causing MN disorders.

Design, synthesis, biological assessment and molecular modeling studies of novel imidazothiazole-thiazolidinone hybrids as potential anticancer and anti-inflammatory agents

A new series of imidazothiazole derivatives bearing thiazolidinone moiety (4a-g and 5a-d) were designed, synthesized and evaluated for potential epidermal growth factor receptor (EGFR) kinase inhibition, anticancer and anti-inflammatory activity, cardiomyopathy toxicity and hepatotoxicity. Compound 4c inhibited EGFR kinase at a concentration of 18.35 ± 1.25 µM, whereas standard drug erlotinib showed IC50 value of 06.12 ± 0.92 µM. The molecular docking, dynamics simulation and MM-GBSA binding energy calculations revealed strong interaction of compound 4c with binding site of EGFR. The synthesized compounds were evaluated for their anticancer activity by MTT assay against three human cancer cell lines A549 (Lung), MCF-7 (Breast), HCT116 (Colon), one normal human embryonic kidney cell line HEK293 and also for their EGFR kinase inhibitory activity. Few compounds of the series (4a, 4b, 4c) showed promising growth inhibition against all the tested cancer cell lines and against EGFR kinase. Among these, compound 4c was found to be most active and displayed IC50 value of 10.74 ± 0.40, 18.73 ± 0.88 against cancer cell lines A549 and MCF7 respectively whereas it showed an IC50 value of 96.38 ± 1.79 against HEK293 cell line indicating lesser cytotoxicity for healthy cell. Compounds 4a, 4b and 4c were also examined for their apoptosis inducing potential through AO/EB dual staining assay and it was observed that their antiproliferative activity against A549 cells is mediated via induction of apoptosis. Cardiomyopathy studies showed normal cardiomyocytes with no marked sign of pyknotic nucleus of compounds 4b and 4c. Hepatotoxicity studies of compounds 4b and 4c also showed normal architecture of hepatocytes. Compounds 4a-g and 5a-d were also evaluated for their in-vitro anti-inflammatory activity by protein albumin denaturation assay. Among the tested compounds 4a-d and 5a-b showed promising activity and were selected for in-vivo inflammatory activity against carrageenan rat paw edema test. Among these compounds, 4b was found to be most active in the series showing 84.94% inhibition, whereas the standard drug diclofenac sodium showed 84.57% inhibition. Compound 4b also showed low ulcerogenic potential and lipid peroxidation. Thus, compounds 4c and 4b could be a promising lead compounds for developing anticancer and anti-inflammatory agents with low toxicity and selectivity.

New pyrazolyl-thiazolidinone/thiazole derivatives as celecoxib/dasatinib analogues with selective COX-2, HER-2 and EGFR inhibitory effects: design, synthesis, anti-inflammatory/anti-proliferative activities, apoptosis, molecular modelling and ADME studies

Two new series of pyrazolyl-thiazolidinone/thiazole derivatives 16a-b and 18a-j were synthesised, merging the scaffolds of celecoxib and dasatinib. Compounds 16a, 16b and 18f inhibit COX-2 with S.I. 134.6, 26.08 and 42.13 respectively (celecoxib S.I. = 24.09). Compounds 16a, 16b, 18c, 18d and 18f inhibit MCF-7 with IC50 = 0.73-6.25 μM (dasatinib IC50 = 7.99 μM) and (doxorubicin IC50 = 3.1 μM) and inhibit A549 with IC50 = 1.64-14.3 μM (dasatinib IC50 = 11.8 μM and doxorubicin IC50 = 2.42 μM) with S.I. (F180/MCF7) of 33.15, 7.13, 18.72, 13.25 and 8.28 respectively higher than dasatinib (4.03) and doxorubicin (3.02) and S.I. (F180/A549) of 14.75, 12.96, 4.16, 7.07 and 18.88 respectively higher than that of dasatinib (S.I. = 2.72) and doxorubicin (S.I = 3.88). Derivatives 16a, 18c, 18d, 18f inhibit EGFR and HER-2 IC50 for EGFR of 0.043, 0.226, 0.388, 0.19 μM respectively and for HER-2 of 0.032, 0.144, 0.195, 0.201 μM respectively.

Agri-Food By-Products in Cancer: New Targets and Strategies

The globalization and the changes in consumer lifestyles are forcing us to face a deep transformation in food demand and in the organization of the entire food production system. In this new era, the food-loss and food-waste security nexus is relevant in the global debate and avoiding unsustainable waste in agri-food systems as well as the supply chain is a big challenge. "Food waste" is useful for the recovery of its valuable components, thus it can assume the connotation of a "food by-product". Sustainable utilization of agri-food waste by-products provides a great opportunity. Increasing evidence shows that agri-food by-products are a source of different bioactive molecules that lower the inflammatory state and, hence, the aggressiveness of several proliferative diseases. This review aims to summarize the effects of agri-food by-products derivatives, already recognized as promising therapeutics in human diseases, including different cancer types, such as breast, prostate, and colorectal cancer. Here, we examine products modulating or interfering in the signaling mediated by the epidermal growth factor receptor.

Design, synthesis, and biological evaluation of new pyrimidine-5-carbonitrile derivatives bearing 1,3-thiazole moiety as novel anti-inflammatory EGFR inhibitors with cardiac safety profile

A new series of pyrimidine-5-carbonitrile derivatives 8a-p carrying the 1,3-thiazole moiety has been designed and synthesized as novel anti-inflammatory EGFR inhibitors with cardiac and gastric safety profiles. 8a-p have been assessed for their inhibitory activity against COX-1/COX-2 activity. Compounds 8h, 8n, and 8p were found to be potent and selective COX-2 inhibitors (IC₅₀ = 1.03-1.71 μM) relative to celecoxib (IC₅₀ = 0.88 μM). The most potent COX-2 inhibitors have been further investigated for their in-vivo anti-inflammatory effect. Compounds 8h, 8n, and 8p showed anti-inflammatory activity up to 90%, 94% and 86% of meloxicam after 4 h interval. 8h, 8n, and 8p showed higher gastric safety profiles than meloxicam. A substantial reduction in serum concentrations of PGE₂, TNF-α, IL-6, iNO and MDA and a significant induction of TAC was also observed. In vivo experiments on heart rate and blood pressure established the cardiovascular safety profile of 8h, 8n, and 8p. Anti-proliferative and wild-type EGFR inhibitory assays displayed similar results to selective COX-2 inhibition where compounds 8h, 8n, and 8p had a superior inhibition than other tested ones. Molecular docking study demonstrated that these compounds revealed similar orientation and binding interactions as selective COX-2 inhibitors with a higher liability to enter the side pocket selectively. Also, they interacted with EGFR tyrosine kinase main amino acids similar to erlotinib with a strong binding energy score.

Tris(2-chloroethyl) Phosphate (TCEP) Elicits Hepatotoxicity by Activating Human Cancer Pathway Genes in HepG2 Cells

Tris(2-chloroethyl) phosphate (TCEP) is one of the organophosphorus flame retardants (OPFRs) used in consumer commodities and have been detected in human body fluids. Research on TCEP-induced transcriptomic alterations and toxicological consequences in liver cells is still lacking. Herein, human hepatocellular (HepG2) cells were treated with 100, 200, and 400 μM TCEP for 3 days to quantify hepatotoxicity by MTT, NRU, and comet assays. Apoptosis, mitochondrial membrane potential (ΔΨm), oxidative stress, and Ca²⁺ influx were measured by flow cytometry. A qPCR array was employed for transcriptomic analysis. MTT and NRU data showed 70.92% and 75.57% reduction in cell survival at 400 μM. In addition, 20-fold greater DNA damage was recorded at 400 μM. Cell cycle data showed 65.96% subG1 apoptotic peak in 400 μM treated cells. An elevated level of oxidative stress, esterase, Ca²⁺ influx, and ΔΨm dysfunction were recorded in TCEP-treated cells. Out of 84 genes, the qPCR array showed upregulation of 17 genes and downregulation of 10 key genes belonging to human cancer pathways. Our study endorses the fact that TCEP possesses hepatotoxic potential at higher concentrations and prolonged exposure. Hence, TCEP may act as a cancer-inducing entity by provoking the gene network of human cancer pathways.

Joint effect of polycyclic aromatic hydrocarbons and phthalates exposure on telomere length and lung function

Exposure to polycyclic aromatic hydrocarbons and phthalates are linked to lung function decline and altered relative telomere length (RTL) accompanying with oxidative stress and inflammatory events in human body. However, limited data are available about impacts of co-exposure of PAHs and phthalates on lung function and RTL. We conducted a pilot study with repeated measures during the winter of 2014 and summer of 2015 in Wuhan city, China. Participants took part in the measures of lung function, RTL, urinary monohydroxylated-PAHs (OH-PAHs) and phthalate metabolites over three consecutive days in each season. Linear mixed-effect (LME) models and Bayesian kernel machine regression (BKMR) were used to analyze the relations of OH-PAHs or phthalate metabolites with lung function or RTL. LME models showed the negative associations of 3-day average of hydroxyphenanthrene (2 + 3-, 4-OHPhe) or 1-hydroxypyrene with FEV1, 3-day average of 2 + 3-OHPhe with FVC. BKMR models revealed the negative relation of eight OH-PAHs with FEV1, FVC or RTL; nine phthalate metabolites may counteract an overall effect of eight OH-PAHs on FEV1, FVC or RTL. The findings indicated that urinary phthalate metabolites may counteract the negative association of urinary OH-PAHs on FEV1 or FVC, which may be partially linked to shorter RTL regarding biological aging.

Effect of exposure to phthalates on association of polycyclic aromatic hydrocarbons with 8-hydroxy-2'-deoxyguanosine

BACKGROUND

Although polycyclic aromatic hydrocarbons (PAHs) and phthalates separately related to oxidative DNA damage have been reported, the joint effect of them on oxidative DNA damage need to be evaluated.

METHODS

In this pilot study, 106 participants were recruited from the community-dwelling residents (n=1240) of Wuhan city, China. Each individual provided three continuous days of spot urine samples for measuring the urinary monohydroxylated PAHs (OH-PAHs), phthalates metabolites and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in the two seasons. Linear mixed effect model and Bayesian Kernel Machine Regression (BKMR) were used to analyze joint effect of urinary PAHs and phthalates metabolites on urinary 8-OHdG levels. We measured cellular and mitochondrial reactive oxygen species (ROS), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) levels as well as IL-6 and IL-8 secretions by the corresponding commercial kits in HepG2 cells treated with di (2-ethylhexyl) phthalate (DEHP, 62.5, 125.00, 250.00, 500.00 or 1000.00μM) alone, benzo[a]pyrene (BaP, 50.00μM) alone or both DEHP and BaP.

RESULTS

Linear mixed effect model showed that each of urinary PAHs metabolite was positively associated with urinary 8-OHdG levels; urinary level of mono (2-ethylhexyl) phthalate or monoisononyl phthalate was positively associated with urinary 8-OHdG levels; BKMR model indicated that a positive association of eight OH-PAHs with urinary 8-OHdG levels, nine urinary phthalates metabolites enhanced the association. We found that DEHP at the indicated concentration plus 50.00μM BaP increased cellular and mitochondrial ROS levels, IL-6 and IL-8 secretions at 24 and 48h as well as MDA levels and GSH-Px activities at 48h, compared to the solvent control.

CONCLUSIONS

Exposure to certain dose phthalates may attenuate the positive association of PAHs exposure with oxidative DNA damage in the body. DEHP at the certain concentrations enhanced BaP-induced mitochondrial ROS, pro-inflammatory response and the activation of the antioxidant defense system in HepG2 cells.

Bioremediation of triphenyl phosphate in river water microcosms: Proteome alteration of Brevibacillus brevis and cytotoxicity assessments

Triphenyl phosphate (TPHP), an organophosphate flame retardant, was detected in river water samples collected from an electronic waste recycling area in Guiyu, Southern China. The concentrations of TPHP ranged from not detected to 347.2 ng/L, with an average of 138.8 ng/L. The bioaugmentation potential of Brevibacillus brevis on TPHP biodegradation by aerobic microcosms contained in river water from Guiyu was assessed. The results showed that TPHP degradation efficiency was significantly improved to 97.9% by bioaugmentation with B. brevis after 96 h incubation. A total of 182 significantly changed proteins in B. brevis were identified and quantified by isobaric tags for relative and absolute quantification (iTRAQ) in response to TPHP stress. The differentially expressed proteins were mainly associated with energy metabolism, lipid metabolism, cell wall biosynthesis, amino acid transport, and metabolism. The identification that proteins of B. brevis respond to TPHP existence provides novel insights into biodegradation mechanisms of bacteria under environmental stress. Additionally, cytotoxicity assays indicated that the degrading intermediates of TPHP, namely diphenyl phosphate and phenyl phosphate, were less cytotoxic to human HepG2 cells compared with TPHP. Collectively, these findings suggest that aerobic bioaugmentation with degrading microorganisms is a potential strategy for in situ treatment of TPHP-contaminated sites.

EGFR inhibitors from cancer to inflammation: Discovery of 4-fluoro-N-(4-(3-(trifluoromethyl)phenoxy)pyrimidin-5-yl)benzamide as a novel anti-inflammatory EGFR inhibitor

EGFR inhibitors are well-known as anticancer agents. Quite differently, we report our effort to develop EGFR inhibitors as anti-inflammatory agents. Pyrimidinamide EGFR inhibitors eliciting low micromolar IC₅₀ and the structurally close non-EGFR inhibitor urea analog were synthesized. Comparing their nitric oxide (NO) production inhibitory activity in peritoneal macrophages and RAW 246.7 macrophages indicated that their anti-inflammatory activity in peritoneal macrophages might be a sequence of EGFR inhibition. Further evaluations proved that compound 4d significantly and dose-dependently inhibits LPS-induced iNOS expression and IL-1β, IL-6, and TNF-α production via NF-κB inactivation in peritoneal macrophages. Compound 4d might serve as a lead compound for development of a novel class of anti-inflammatory EGFR inhibitors.