Different Concentrations Of Benzo(a)pyrene Research Articles

Impacts of benzo(a)pyrene exposure on scallop (Chlamys farreri) gut health and gut microbiota composition

The gut tissue interacts with nutrients and pollutants which can impact gut health. Gut microbiota is essential to the host health, but is also easily affected by external environment. However, little is known about the toxicological assessment of environmental contaminants on gut health and microbiota, especially in marine invertebrates. In this study, we first explored the effect of benzo(a)pyrene (BaP) on the gut health and gut microbiota of scallops (Chlamys farreri). The scallops were exposed to different concentrations (0, 0.4, 2 and 10 μg/L) of BaP for 21 days. The histological morphology, immune- and oxidative enzyme-related gene expression, and lipid peroxidation of the scallops were analyzed at 7, 14 and 21 days. The results revealed that BaP could impair intestinal barrier function, increasing the intestinal permeability of scallops. Moreover, immune and antioxidant responses were induced in the gut tissue. After a 21-day exposure to different concentrations of BaP, the intestinal microbial community was analyzed based on 16S rRNA sequencing. Our results suggested that BaP exposure altered the gut microbial diversity and composition in scallops. Many beneficial genera declined after BaP treatment, while the potential pathogens were increased, such as Mycoplasma and Tenacibaculum. A series of hydrocarbon-degrading bacteria were recognized in BaP-treated groups, such as Pseudomonas, Polaribacter, Amphritea and Kordiimonas. Interestingly, the degrading bacteria present varied after exposure to different concentrations of BaP. Overall, this study provides new insights into gut health and gut microbiota in marine invertebrates following exposure to persistent organic pollutants.

Induction of proliferative and mutagenic activity by benzo(a)pyrene in PC-3 cells via JAK2/STAT3 pathway

Environmental carcinogen benzo(a)pyrene (BaP) is a representative compound of polycyclic aromatic hydrocarbons (PAHs). BaP is strongly associated with prostate carcinogenesis. However, the molecular mechanism of BaP in development of prostate carcinoma remains largely unknown. The aim of this study was to investigate the effect and mechanism of BaP on the development in prostate cancer. PC-3 cells were exposed to different concentrations of BaP for 24, 48, 72 h, respectively. We analyzed the effect of BaP on PC-3 cell viability, cell cycle, DNA strand breaks, mutagenic activity, and migration. The expression of associated regulatory genes and the effect of JAK2/STAT3 signaling were also measured to explore the relationships among BaP metabolism, the JAK2/STAT3 pathway and proliferative activity in PC-3 cells. We observed significant effects on proliferation, DNA strand breaks and mutagenic activity after BaP exposure in PC-3 cells, and inhibitors of CYP1 and the AhR transcription factor α -naphthoflavone (ANF) and CH223191 treatment clearly reduced both cell survival and mutagenesis associated with BaP exposure. Reduction in G0-G1 phase population and elevation in S phase were observed after BaP exposure. Migratory cells for PC-3 were significantly increased. The results were further confirmed by the expression of mRNA levels in the significant increments of Snail, Slug, MMP-9, CYP1A1, CYP1B1, CycilnD1, CDK4 and significant reduction of E-cadherin. Significant enhancements were found in the expression of JAK2, STAT3 after BaP treatment. Additionally, activator IL-6 significantly enhanced the effect of BaP on cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression in PC-3 cells. Significant reductions in cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression were found after inhibitor AG490, ANF and CHJ223191 treatment. These findings reveal that BaP enhances the proliferative and mutagenic activity via JAK2-STAT3 pathway in PC-3 cells, and provide the additional evidence to understand the crucial role of BaP in prostate cancer carcinogenesis.

Using ovarian and brain cell culture from the Mullet, Liza klunzingeri, to assess the inhibitory effects of benzo[a]pyrene on aromatase activity.

We assessed the toxic effects of benzo[a]pyrene (BaP) on cell viability, aromatase (Aro) activity and steroid production using ovarian and brain cell cultures obtained from Mullet, Liza klunzingeri. The brain and ovary were minced and digested, and the cells were suspended in Leibovitz's L-15 medium supplemented with 15% and 20% fetal bovine serum. The cell suspensions were seeded on 25-cm2 cell-culture flasks at 1 × 106 cells/mL and incubated at 25 °C for 2 weeks. A BaP concentration of 10-5 mol/L was accepted as the half-maximal inhibitory concentration. Ovarian and brain cells were exposed to different concentrations of BaP [0 (control), 10-6 , 2 × 10-6 , 3 × 10-6 mol/L] and incubated at 30 °C. At different sampling times (0, 12, 24 and 48 h) 40 ng/105 cells of 1,4,6-androstatriene-3,17-dione (ATD) was added to each well. Aro activity, 17β-estradiol (E2) and ATD production were determined. The sensitivity of the cultivated ovarian and brain cells to BaP increased dose dependently. BaP was a potent inhibitor of Aro activity at 2 × 10-6 and 3 × 10-6 mol/L, both in the cultivated brain and ovarian cells at different sampling times, with 10-6 mol/L BaP found to be the least potent Aro inhibitor. E2 production decreased from cultivated ovarian and brain cells treated by different concentrations of BaP. In conclusion, BaP is able to change the activity of Aro and disrupt the biosynthesis of estrogens, and thus affects reproduction in fish.

Benzo(a)pyrene inhibits endometrial cell apoptosis in early pregnant mice via the WNT5A pathway.

Benzo(a)pyrene (BaP) is an endocrine-disrupting pollutant present in various aspects of daily life, and studies have demonstrated that BaP exerts reproductive toxicity. We previously showed that BaP damages endometrial morphology and decreases the number of implantation sites in early pregnant mice, but the mechanisms underlying these effects remain unclear. The endometrial function is crucial for implantation, which is associated with endometrial cell apoptosis. In this study, we focused on the effect of BaP on endometrial cell apoptosis and the role of WNT signaling during this process. Pregnant mice were gavaged with corn oil (control group) or 0.2 mg·kg-1 ·day -1 BaP (treatment group) from Days 1 to 6 of pregnancy. BaP impaired endometrial function by decreasing the expression of HOXA10 and BMP2, two markers of receptivity and decidualization. WNT5A and β-catenin were activated in the BaP group. BaP affected the expression of apoptosis-related proteins and inhibited the apoptosis of endometrial stromal cells. In vitro, human endometrial stromal cells (HESCs) were treated with different concentrations of BaP (dimethyl sulfoxide (DMSO); 5, 10 µM). WNT5A and β-catenin were also upregulated in the BaP treatment group. HESC apoptosis was restrained by BaP. Inhibiting WNT5A by SFRP5 partially restored the effect of BaP on apoptosis. In summary, these results suggested that BaP exposure during early pregnancy activates WNT5A/β-catenin signaling pathway, which inhibits the endometrial cell apoptosis and potentially destroys endometrial function.

Benzo(a)pyrene promotes migration, invasion and metastasis of lung adenocarcinoma cells by upregulating TGIF

This study aimed to investigate the potential roles of TG-interacting factor (TGIF) in benzo(a)pyrene (BaP)-induced migration, invasion, and metastasis of lung adenocarcinoma cells. Cells were treated with different concentrations of BaP. MTT assays were used to measure cell proliferation. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunoblots were applied to measure the TGIF expression. A dual-luciferase reporter gene assay was performed to assess the effects of BaP on TGIF promoter-driven reporter gene expression. Wound-healing, transwell, and tail vein metastasis assays were performed to evaluate migratory, invasive, and metastatic capacity. Our results showed that BaP treatment increased the expression of TGIF mRNA and protein. Additionally, BaP treatment enhanced TGIF promoter-driven reporter gene expression. We observed that BaP treatment promoted the migration, invasion, and metastasis of H157 cells, which could be blocked by silencing TGIF. The expression of TGIF mRNA was significantly higher in metastatic lung adenocarcinoma samples than in non-metastatic lung adenocarcinoma samples, and higher levels of TGIF mRNA expression were observed in metastatic lung adenocarcinoma samples from patients with a smoking history than in those from patients with a non-smoking history. Our findings suggest that BaP treatment promotes the migration, invasion, and metastasis of human lung adenocarcinoma cells by upregulating TGIF.

Effects of benzo[a]pyrene, aromatic amines, and a combination of both on CYP1A1 activities in RT-4 human bladder papilloma cells

ABSTRACTThe interaction of arylamines and polycyclic aromatic hydrocarbons (PAH) is of particular interest in the etiology of bladder cancer. The aim of this study was to (1) examine the metabolic capacity of RT-4 human bladder papilloma cells and (2) investigate the influence of aromatic amines on the induction of cytochrome P-450 1A1 (CYP1A1) activity and their effects on benzo[a]pyrene (BaP)-induced CYP1A1 activities. Cells were incubated for 24 h with different concentrations of BaP, 1- or 2-naphthylamine (NA), 2-, 3-, or 4-aminobiphenyl (ABP), and binary mixtures consisting of 1 µM BaP and different concentrations of each arylamine. Changes in CYP1A1 activities were measured at concentrations with no or only low cytotoxicity and accompanied by specific protein detection. Several phase I and II enzymes relevant to metabolism of PAH and arylamines were present in RT-4 cells. Concentration-dependent elevation in CYP1A1 activities accompanied by increasing protein levels was found after treating cells with BaP and 1- or 2-NA. The majority of synergistic effects in binary mixtures were less than additive. In contrast, concentration-dependent inhibition was observed for 2-, 3-, and 4-ABP and in both the presence and absence of BaP. Our results suggest that RT-4 cells represent a reliable model cell line to study arylamine- and PAH-induced effects in vitro and that BaP-induced CYP1A1 activities are modulated by aromatic amines. In general, the direction of the effect depends upon the aromatic amine, rather than being unidirectional for aromatic amines.

SAT0058 Slug is induced by benzo(a)pyrene and egf through PI3K/AKT/MTOR pathway and is closely involved in the regulation of the invasive properties of FLS in rheumatoid arthritis

BackgroundSlug, a Snail family of zinc finger transcription factor, plays a critical role in tumor proliferation, invasion and metastasis. We have previously shown that Slug is overexpressed in RA synovial...

Benzo[a]pyrene modulation of acute immunologic responses in red Sea bream pretreated with lipopolysaccharide

The effects of polycyclic aromatic hydrocarbons (PAHs) have been reported to modulate the immune response in aquatic animals, but the collected information of their effects on fish immunity is so far ambiguous. This study demonstrated that Benzo[a]pyrene (BaP) exposure altered the expression pattern of an antimicrobial peptide hepcidin (PM-hepc) gene and the activities of some immune-associated parameters in the lipopolysaccharide (LPS)-challenged red sea bream (Pagrus major). It was observed that LPS could increase respiratory burst, lysozyme and antibacterial activity in P. major. However when the P. major was exposed to different concentrations of BaP (1, 4, or 8 μg L(-1) ) for 14 days and then challenged with LPS there was no significant change in the lysozyme and antibacterial activity. It was further observed that LPS could induce the PM-hepc mRNA expression at 3, 6, and 12-h post-LPS challenge. However, when P. major was exposed first to BaP for 14 days and then challenged with LPS, the expression of PM-hepc mRNA was delayed in the liver until 24 h and not significantly induced until 48 and 96 h. The mRNA expression pattern was completely different from that only with LPS challenge, showing that BaP exposure changed the PM-hepc mRNA expression pattern of fish with LPS challenge. This study demonstrated that BaP exposure can weaken or inhibit the induction of lysozyme and antibacterial activity in the LPS-challenged P. major; conversely BaP exposure could enhance the mRNA expression of PM-hepc gene, indicating that the effect of BaP has different modulatory mechanism on hepcidin genes and immune-associated parameters.

Nuclear proteome analysis of benzo(a)pyrene-treated HeLa cells

Previously, we employed a proteomics-based 2-D gel electrophoresis assay to show that exposure to 10μM benzo(a)pyrene (BaP) during a 24 h frame can lead to changes in nuclear protein expression and alternative splicing. To further expand our knowledge about the DNA damage response (DDR) induced by BaP, we investigated the nuclear protein expression profiles in HeLa cells treated with different concentrations of BaP (0.1, 1, and 10μM) using this proteomics-based 2-D gel electrophoresis assay. We found 125 differentially expressed proteins in BaP-treated cells compared to control cells. Among them, 79 (63.2%) were down-regulated, 46 (36.8%) were up-regulated; 8 showed changes in the 1μM and 10μM BaP-treated groups, 2 in the 0.1μM and 10μM BaP-treated groups, 4 in the 0.1μM and 1μM BaP-treated groups, and only one showed changes in all three groups. Fifty protein spots were chosen for liquid chromatography–tandem mass spectrometry (LC–MS/MS) identification, and of these, 39 were identified, including subunits of the 26S proteasome and Annexin A1. The functions of some identified proteins were further examined and the results showed that they might be involved in BaP-induced DDR. Taken together, these data indicate that proteomics is a valuable approach in the study of environmental chemical–host interactions, and the identified proteins could provide new leads for better understanding BaP-induced mutagenesis and carcinogenesis.

Cytotoxic effect of benzo(a)pyrene on development and protein pattern of sunflower pollen grains

Benzo(a)pyrene (BaP) is an important part of diesel exhaust particles (DEP). The overall objective of this research was to elucidate some microscopic effects of BaP on the formation, development, and structure of pollen grains and its proteins in sunflower (Helianthus annuus L). Sunflower plants were grown in experimental pots and treated with the different concentrations of BaP. Flowers and young buds were removed, fixed in FAA70 (formalin:acetic acid:ethanol, 2 : 1 : 17) and subjected to developmental studies. Our results show that BaP-treatment causes abnormalities during pollen development. Shape of microspore tetrads changed from spherical to polygonal or irregular. Pollen grains in normal plants are spherical in both equatorial and polar views; in BaP-treated plants, they changed into irregular shapes in equatorial view and triangular shape in polar view. Delay in degeneration of the tapetum layer in anther, and formation of giant, irregular, and non-fertile pollen grains are other results of BaP treatment. Gel electrophoretic studies revealed that a band with a molecular mass of 30 kDa disappeared in the BaP-treated group and two new proteins with molecular masses of 15 and 20 kDa were formed. Some pollen proteins may act as allergens, considering the fact that pollen allergy frequency is increased in polluted areas, especially DEP-polluted ones; the possibility arises that BaP, as an important part of DEP, could be an effective agent entailing formation of detoxifying proteins which, on the other hand, can also act as allergens.

Correlations and co-localizations of Hsp70 with XPA, XPG in human bronchial epithelia cells exposed to benzo[a]pyrene

Benzo[a]pyrene (BaP) is a ubiquitously distributed environmental pollutant known to cause DNA damage, which may be repaired through nucleotide excision repair (NER). The significantly negative correlation between Hsp70 levels and the level of DNA damage in workers exposed to coke oven emission had been found. However, little is known about how Hsp70 modulate the DNA repair process. In a series of experiments using the human bronchial epithelia cells (16HBE) exposed to different concentrations of BaP for 24 h, we measured expression of NER subunit xeroderma pigmentosum (XP) group A, C, F, G (XPA, XPC, XPF, XPG), excision repair cross-complementing 1 (ERCC1) and Hsp70, and analyzed their possible correlations. Co-localizations of Hsp70 with NER subunit were detected by confocal microscope. We found that in vitro exposure to BaP reduced cell viability in a dose-dependent manner ranging from 2 to 64 μM. Our results showed that levels of XPA, XPG and Hsp70 significantly increased at cells exposed to 1 or 2 μM BaP. In addition, curve estimation showed there was a significant correlation between relative ratios of Hsp70 and XPA, XPG in cells exposed to different concentrations of BaP. Moreover, confocal microscopy demonstrated increased co-localization of Hsp70 with XPA, XPG in nuclei of cells exposed to BaP. These results suggested that Hsp70 might play a role in nucleotide excision repair. However, the mechanisms underlying this observation need further investigation.

Dynamic changes of XPA, XPC, XPF, XPG and ERCC1 protein expression and their correlations with levels of DNA damage in human bronchial epithelia cells exposed to benzo[a]pyrene

Benzo[a]pyrene (BaP) is a ubiquitously distributed environmental pollutant known to cause DNA damage, which may be repaired through nucleotide excision repair (NER). However, little is known about dynamic changes in levels of DNA damage and their correlations with levels of NER proteins in cells exposed to BaP. In a series of experiments using the human bronchial epithelia cells (16HBE) exposed to different concentrations of BaP for different times, we measured dynamic changes in levels of DNA damage and expression of NER subunit xeroderma pigmentosum (XP) groups A, C, F, G (XPA, XPC, XPF, XPG) and excision repair cross-complementing 1 (ERCC1), and analyzed their possible correlations. We found that in vitro exposure to BaP reduced cell viability in a dose-dependent manner ranging from 2 to 64 μM and increased DNA damage in a dose- and time-dependent manner. Our results showed that levels of these NER proteins significantly increased and peaked at 12th or 24th, 8th or 12th and 4th or 8th hours in cells exposed to 2, 8 and 16 μM BaP, respectively. ERCC1 expression increased by 2.4-, 4.2- and 19.3-fold for exposure to 2, 8 and 16 μM BaP, respectively, compared with control group. Moreover, levels of ERCC1 in cells exposed 16 μM BaP significantly higher than those in 2 and 8 μM BaP from 2nd to 48th hours. In addition, there was a significant positive correlation between Olive tail moments and relative ratios of ERCC1 in cells exposed to BaP. Our results suggested ERCC1 may be an important limiting factor for NER, but the mechanisms underlying this observation needs further investigation.

Role of heat shock protein 70 expression in DNA damage induced by benzo(a)pyrene

To explore heat shock protein 70 (HSP70) expression of A549 cells and its role in DNA damage caused by benzo(a)pyrene (BaP). Human adenocarcinoma A549 cells were cultured in vitro, exposed by different concentrations of BaP (0, 1.25, 2.50, 5.00, 10.00 micro mol/L) for 6 hours, or 10 micro mol/L of BaP for different time (0, 4, 8, 12, 16, 24 and 48 h). Then HSP70 expression and DNA damage were detected using Western-blot and single cell gel electrophoresis (SCGE) assay respectively, and the relationship between HSP70 expression and DNA damage was further analyzed. The integral optical densities of HSP70 in A549 cells treated with 1.25, 2.50, 5.00 and 10.00 micro mol/L BaP for 6 h (49.63 +/- 1.30, 45.72 +/- 1.03, 40.53 +/- 0.95, 37.50 +/- 1.20 respectively) were lower than that of the control cells (59.43 +/- 1.17) (P < 0.05). When A549 cells were exposed to 10 micro mol/L BaP for 4, 8, 12, 16 h, the integral optical densities of HSP70 were 33.33 +/- 0.80, 29.23 +/- 0.91, 12.51 +/- 0.96, 9.50 +/- 1.25 respectively, and there was an increasing tendency of the expression of HSP70 for 24 - 48 h (20.06 +/- 1.38, 24.51 +/- 1.39), however, all were different from that in control group (56.59 +/- 0.85) (P < 0.05). DNA damage scores in 10(6) A549 cells treated with 2.50, 5.00 and 10.00 micro mol/L BaP for 6 h (23,718 +/- 2,938, 30,128 +/- 2,937, 44,231 +/- 3,846) were significantly higher than that of the control cell (9,615 +/- 1,923) (P < 0.05). When A549 cells were exposed to 10 micro mol/L BaP for 4, 8, 12, 16, 24, 48 h, DNA damage scores (16,667 +/- 4,003, 38,461 +/- 1,924, 5,615 +/- 3,847, 76,282 +/- 2,937, 7,513 +/- 1,110 and 58,975 +/- 9,487) were also higher than that of control group (P < 0.05). There was a negative correlation between DNA damage and the expression of HSP70 when A549 cells were exposed to different concentrations of BaP. HSP70 might enhance intracellular defenses against DNA damage induced by BaP.