Di-n-butyl phthalate epigenetically induces reproductive toxicity via the PTEN/AKT pathway.
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ABSTRACT:
SUBMITTER: Li R
PROVIDER: S-EPMC6450951 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: Di-n-butyl phthalate (DBP), a chemical widely used in many consumer products, is estrogenic and capable of producing seriously reproductive and developmental effects in laboratory animals. However, recent in vitro studies have shown that DBP and mono-n-butyl phthalate (MBP), the major metabolite of DBP, possessed thyroid hormone receptor (TR) antagonist activity. It is therefore important to consider DBP and MBP that may interfere with thyroid hormone system. METHODOLOGY/PRINCIPAL FINDINGS: Nieuwkoop and Faber stage 51 Xenopus laevis were exposed to DBP and MBP (2, 10 or 15 mg/L) separately for 21 days. The two test chemicals decelerated spontaneous metamorphosis in X. laevis at concentrations of 10 and 15 mg/L. Moreover, MBP seemed to possess stronger activity. The effects of DBP and MBP on inducing changes of expression of selected thyroid hormone response genes: thyroid hormone receptor-beta (TR?), retinoid X receptor gamma (RXR?), alpha and beta subunits of thyroid-stimulating hormone (TSH? and TSH?) were detected by qPCR at all concentrations of the compounds. Using mammalian two-hybrid assay in vitro, we found that DBP and MBP enhanced the interactions between co-repressor SMRT (silencing mediator for retinoid and thyroid hormone receptors) and TR in a dose-dependent manner, and MBP displayed more markedly. In addition, MBP at low concentrations (2 and 10 mg/L) caused aberrant methylation of TR? in head tissue. CONCLUSIONS: The current findings highlight potential disruption of thyroid signalling by DBP and MBP and provide data for human risk assessment.
| S-EPMC3081329 | biostudies-literature
Project description:Di-(2-ethylhexyl) phthalate (DEHP) is one of the most commonly used plasticizers, and it is widely applied in various plastic products. DEHP is an endocrine-disrupting chemical (EDC) that has been shown to disrupt the function of reproductive system in females. Although many studies have shown that DEHP potentially causes female reproductive toxicity, including depletion of the primordial follicle and decreased sex hormone production, the specific mechanisms by which DEHP affects female reproduction remain unknown. In recent years, research focused on the intestinal flora has provided an idea to eliminate our confusion, and gut bacterial dysbiosis may contribute to female reproductive toxicity. In the present study, the feces of DEHP-exposed mice were collected and analyzed using 16S rRNA amplicon sequencing and untargeted global metabolite profiling of metabolomics. DEHP obviously causes reproductive toxicity, including the ovarian organ coefficient, estradiol level, histological features of the ovary and estrus. Furthermore, DEHP exposure alters the structure of the intestinal microbiota community and fecal metabolite profile in mice, suggesting that the reproductive toxicity may be caused by gut bacterial dysbiosis and altered metabolites, such as changes in the levels of short-chain fatty acid (SCFA). Additionally, it is well known that changes in gut microbiota and fecal metabolites cause inflammation and tissue oxidative stress, expectedly, we found oxidative stress in the ovary and systemic inflammation in DEHP exposed mice. Thus, based on our findings, DEHP exposure may cause gut bacterial dysbiosis and altered metabolite profiles, particularly SCFA profiles, leading to oxidative stress in the ovary and systemic inflammation to ultimately induce female reproductive toxicity.
| S-EPMC8251547 | biostudies-literature
Project description:Although DBP (di-n-butyl phthalate) is commonly encountered as an artificially-synthesized plasticizer with potential to impair fertility, we confirm that it can also be biosynthesized as microbial secondary metabolites from naturally occurring filamentous fungi strains cultured either in an artificial medium or natural water. Using the excreted crude enzyme from the fungi for catalyzing a variety of substrates, we found that the fungal generation of DBP was largely through shikimic acid pathway, which was assembled by phthalic acid with butyl alcohol through esterification. The DBP production ability of the fungi was primarily influenced by fungal spore density and incubation temperature. This study indicates an important alternative natural waterborne source of DBP in addition to artificial synthesis, which implied fungal contribution must be highlighted for future source control and risk management of DBP.
| S-EPMC4746570 | biostudies-literature
Project description:Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance is a major obstacle in the treatment of non-small cell lung cancer (NSCLC). Epigenetic alterations have been shown to be involved in NSCLC oncogenesis; however, their function in EGFR-TKI resistance remains uncharacterized. Here, we found that an EHMT2 inhibitor, UNC0638, can significantly inhibit cell growth and induce apoptosis in EGFR-TKI-resistant NSCLC cells. Additionally, we also found that EHMT2 expression and enzymatic activity levels were elevated in EGFR-TKI-resistant NSCLC cells. Moreover, we determined that genetic or pharmacological inhibition of EHMT2 expression enhanced TKI sensitivity and suppressed migration and tumor sphere formation in EGFR-TKI-resistant NSCLC cells. Further investigation revealed that EHMT2 contributed to PTEN transcriptional repression and thus facilitated AKT pathway activation. The negative relationship between EHMT2 and PTEN was confirmed by our clinical study. Furthermore, we determined that combination treatment with the EHMT2 inhibitor and Erlotinib resulted in enhanced antitumor effects in a preclinical EGFR-TKI-resistance model. We also found that high EHMT2 expression along with low PTEN expression can predict poor overall survival in patients with NSCLC. In summary, our findings showed that EHMT2 facilitated EGFR-TKI resistance by regulating the PTEN/AKT pathway in NSCLC cells, suggesting that EHMT2 may be a target in the clinical treatment of EGFR-TKI-resistant NSCLC.
| S-EPMC5833639 | biostudies-literature
Project description:Gastric cancer (GC) serves as a common malignancy. Long non-coding RNAs (lncRNAs) have been proven to regulate many cancers, including GC. Long intergenic non-protein-coding RNA 511 (LINC00511) has been poorly studied in GC, but its detailed regulatory mechanism has not been identified. Here, LINC00511 was detected to be highly expressed in GC cells. Functional assays were conducted and uncovered that LINC00511 boosted cell proliferation, migration, stemness and EMT process while inhibiting the apoptosis of GC cells. From a series of mechanism experiments, it was found that at the transcriptional level, LINC00511 recruited EZH2 (enhancer of zeste 2 polycomb repressive complex 2 subunit) to the promoter of PTEN (phosphatase and tensin homolog) and facilitated methylation of PTEN promoter. LINC00511 epigenetically repressed PTEN to activate the PI3K/AKT pathway. Moreover, SRY-box transcription factor 4 (SOX4) activated the transcription of LINC00511. At the post-transcriptional level, LINC00511 sponged miR-195-5p to elevate SOX4 expression in GC cells. On the whole, the present study disclosed that SOX4-induced LINC00511 activated SOX4 via competing endogenous RNA (ceRNA) pattern and epigenetically repressed PTEN to activate PI3K/AKT pathway by recruiting EZH2, thus facilitating GC cell proliferation, migration and stemness while inhibiting GC cell apoptosis.
| S-EPMC8500959 | biostudies-literature
Project description:Endocrine disruptors, such as phthalates, are suspected of affecting reproductive function. The Mesalamine and Reproductive Health Study (MARS) was designed to address the physiological effect of in-vivo phthalate exposure on male reproduction in patients with Inflammatory Bowel Disease (IBD). As part of this effort, sperm RNA profiles as an effect of exposure to DBP were longitudinally assessed using a cross-over cross-back design of binary, high or background, levels of DBP. As the DBP level was altered, numerous sperm RNA elements were differentially expressed, and suggest that exposure to or removal from high DBP produces effects that require longer than one spermatogenic cycle to resolve. In comparison, small RNAs are minimally affected by DBP exposure. While initial study medication (high or background) implicates different biological pathways, initiation on the high-DBP condition activated oxidative stress and DNA damage pathways. Using ejaculated sperm, this work provides insight into the male germline’s response to phthalate exposure.
2019-09-06 | GSE129216 | GEO
Project description:Fundamental considerations indicate that, for certain phthalate esters, dermal absorption from air is an uptake pathway that is comparable to or greater than inhalation. Yet this pathway has not been experimentally evaluated and has been largely overlooked when assessing uptake of phthalate esters.This study investigated transdermal uptake, directly from air, of diethyl phthalate (DEP) and di(n-butyl) phthalate (DnBP) in humans.In a series of experiments, six human participants were exposed for 6 hr in a chamber containing deliberately elevated air concentrations of DEP and DnBP. The participants either wore a hood and breathed air with phthalate concentrations substantially below those in the chamber or did not wear a hood and breathed chamber air. All urinations were collected from initiation of exposure until 54 hr later. Metabolites of DEP and DnBP were measured in these samples and extrapolated to parent phthalate intakes, corrected for background and hood air exposures.For DEP, the median dermal uptake directly from air was 4.0 ?g/(?g/m(3) in air) compared with an inhalation intake of 3.8 ?g/(?g/m(3) in air). For DnBP, the median dermal uptake from air was 3.1 ?g/(?g/m(3) in air) compared with an inhalation intake of 3.9 ?g/(?g/m(3) in air).This study shows that dermal uptake directly from air can be a meaningful exposure pathway for DEP and DnBP. For other semivolatile organic compounds (SVOCs) whose molecular weight and lipid/air partition coefficient are in the appropriate range, direct absorption from air is also anticipated to be significant.
| S-EPMC4590762 | biostudies-other
Project description:A Gram-negative strain (TJ) capable of growing aerobically on mixed phthalate esters (PAEs) as the sole carbon and energy source was isolated from the Haihe estuary, Tianjin, China. It was identified as belonging to the Sphingobium genus on the basis of morphological and physiological characteristics and 16S rRNA and gyrb gene sequencing. The batch tests for biodegradation of di-n-butyl phthalate (DBP) by the Sphingobium sp. TJ showed that the optimum conditions were 30 °C, pH 7.0, and the absence of NaCl. Stain TJ could tolerate up to 4% NaCl in minimal salt medium supplemented with DBP, although the DBP degradation rates slowed as NaCl concentration increased. In addition, substrate tests showed that strain TJ could utilize shorter side-chained PAEs, such as dimethyl phthalate and diethyl phthalate, but could not metabolize long-chained PAEs, such as di-n-octyl phthalate, diisooctyl phthalate, and di-(2-ethyl-hexyl) phthalate. To our knowledge, this is the first report on the biodegradation characteristics of DBP by a member of the Sphingobium genus.
| S-EPMC3876093 | biostudies-literature
Project description:The goal of this study was to determine the effects of a well-characterized anti-androgen, abiraterone acetate, and a suspected human anti-androgen, di-n-butyl phthalate (DBP) on the androgenic function of human fetal testis. Human fetal testis was xenografted into the renal subcapsular space of castrated male athymic nude mice. Hosts were treated with hCG to stimulate testosterone production in the xenografts, and were concurrently treated with either abiraterone acetate or DBP. While abiraterone acetate (14 d, 75 mg/kg/d p.o.) dramatically reduced testosterone and the weights of androgen-sensitive host organs, DBP (14 d, 500 mg/kg/d p.o.) had no effect on androgenic endpoints. Three paired analyses were performed using the LIMMA package in R (commands lmfit and eBayes), with the Benjamini-Hochberg correction for multiple comparisons (Smyth 2005): vehicle-treated xenografts vs. unimplanted testis (n=5), abiraterone-treated xenografts vs. matched control xenografts (n=3), and DBP-treated xenografts vs. matched control xenografts (n=3). There were significant differences in gene expression between grafted and ungrafted samples, including dramatic upregulation of microRNAs. Gene expression analysis also showed that abiraterone decreased expression of genes related to cell differentiation, while DBP induced expression of oxidative stress response genes and decreased expression of factors related to embryonic development. 17 xenograft samples were analyzed, including 5 unimplanted samples, 6 vehicle treated xenografts, 3 abiraterone acetate-treated xenografts, and 3 DBP-treated xenografts. Samples were paired (derived from the same donor tissue) for each comparison: vehicle vs. unimplanted (n=5), abiraterone vs. vehicle (n=3), and DBP vs. vehicle (n=3).
2013-10-31 | E-GEOD-49244 | biostudies-arrayexpress
Project description:The goal of this study was to determine the effects of a well-characterized anti-androgen, abiraterone acetate, and a suspected human anti-androgen, di-n-butyl phthalate (DBP) on the androgenic function of human fetal testis. Human fetal testis was xenografted into the renal subcapsular space of castrated male athymic nude mice. Hosts were treated with hCG to stimulate testosterone production in the xenografts, and were concurrently treated with either abiraterone acetate or DBP. While abiraterone acetate (14 d, 75 mg/kg/d p.o.) dramatically reduced testosterone and the weights of androgen-sensitive host organs, DBP (14 d, 500 mg/kg/d p.o.) had no effect on androgenic endpoints. Three paired analyses were performed using the LIMMA package in R (commands lmfit and eBayes), with the Benjamini-Hochberg correction for multiple comparisons (Smyth 2005): vehicle-treated xenografts vs. unimplanted testis (n=5), abiraterone-treated xenografts vs. matched control xenografts (n=3), and DBP-treated xenografts vs. matched control xenografts (n=3). There were significant differences in gene expression between grafted and ungrafted samples, including dramatic upregulation of microRNAs. Gene expression analysis also showed that abiraterone decreased expression of genes related to cell differentiation, while DBP induced expression of oxidative stress response genes and decreased expression of factors related to embryonic development.
2013-10-31 | GSE49244 | GEO