Polycyclic Aromatic Hydrocarbon-induced Pulmonary Carcinogenesis in Cytochrome P450 (CYP)1A1- and 1A2-Null Mice: Roles of CYP1A1 and CYP1A2

Polycyclic Aromatic Hydrocarbons Regulate the Occurrence and Development of Nasopharyngeal Carcinoma by Regulating Aryl Hydrocarbon Receptor

Nasopharyngeal carcinoma (NPC) has hidden onset, low rate of early diagnosis, and most of them have metastases at the time of diagnosis. The specific pathogenesis of NPC is still unclear. Polycyclic aromatic hydrocarbons (PAHs) are a large group of contaminants produced by the incomplete combustion of organic matter and widespread in the air. Many of these compounds are mutagenic and carcinogenic. PAHs plays an important role in mutagenic and carcinogenic, while its role in NPC still needs further elucidation. In this study, CNE-2 cells were stimulated by PAHs, then the expression of aryl hydrocarbon receptor (AhR) and CYP1A2 were respectively examined using Real-Time fluorescence quantitative PCR (qRT-PCR) and Western Blot. CNE-2 cells proliferation, migration, invasion and apoptosis were examined by CCK-8, Wound-Healing Assay, Transwell, Flow Cytometry, respectively. We found that AhR expression was increased while the level of apoptosis was inhibited by PAHs. While the ability of cell invasion was weakened, proliferation and migration were not significantly different. After treated by PAHs and ITE, the effect of PAHs on promoting AhR expression was significantly inhibited and apoptosis was up-regulated. The present study found that, PAHs inhibit apoptosis of NPC cells and promote the expression of AhR. Besides, PAHs participates in NPC occurrence and development by regulating AhR expression. Collectively, these findings may provide a possible strategy for the clinical treatment of NPC.

MiR-222-3p loaded stem cell nanovesicles repair myocardial ischemia damage via inhibiting mitochondrial oxidative stress

AIMS

Mitochondrial oxidative stress (MOS) is a key contributor to poor cardiac function and a major driver of myocardial ischemia-reperfusion injury (MIRI). Our previous research demonstrated that stem cell-derived nanovesicles (NVs) enhanced cardiac function following ischemia-reperfusion (I/R) injury, although the underlying mechanisms remain unclear. We constructed and characterized miR-222-3p-loaded NVs.

MATERIALS AND METHODS

An in vitro hypoxia-reoxygenation (H/R) model was established using H9C2 cardiomyocytes. Mitochondrial oxidative respiratory function was assessed using Seahorse XF technology, while mitochondrial reactive oxygen species (mtROS) levels were quantified via flow cytometry. Additional assessments included mitochondrial permeability transition pore (mPTP) status, mitochondrial membrane potential, and mitochondrial DNA (mtDNA) integrity. An in vivo H/R model was developed using C57BL/6 mice. The therapeutic effects of NVs on MOS reduction and cardiac function improvement were evaluated through Masson's staining, immunofluorescence, echocardiography, transmission electron microscopy (TEM), and positron emission tomography/computed tomography (PET/CT).

KEY FINDINGS

RNA immunoprecipitation (RIP) confirmed that miR-222-3p directly targets cyp1a1. Overexpression of miR-222-3p or knockdown of cyp1a1 significantly improved mitochondrial activity in cardiomyocytes and conferred protection against I/R injury. Conversely, overexpression of cyp1a1 abrogated the protective effects of miR-222-3p. In vivo, NV treatment enhanced cardiac function, reduced MOS, and improved mitochondrial respiratory capacity in MIRI model mice. NV treatment, via miR-222-3p-mediated suppression of cyp1a1, mitigates MOS, enhances mitochondrial respiratory function, and improves cardiac outcomes in MIRI models.

SIGNIFICANCE

These findings provide a foundational basis for the clinical translation of NV-based therapies.

KCNJ15 inhibits chemical-induced lung carcinogenesis and progression through GNB1 mediated Hippo pathway

Polycyclic aromatic hydrocarbons (PAHs) are important environmental carcinogens that can cause lung cancer. However, the underlying epigenetic mechanism during PAHs-induced lung carcinogenesis has remained largely unknown. Previously, we screened some novel epigenetic regulatory genes during 3-methylcholanthrene (3-MCA)-induced lung carcinogenesis, including the potassium inwardly rectifying channel subfamily J member 15 (KCNJ15) gene. This study aimed to investigate the expression regulation, function, and mechanism of KCNJ15 through database analysis, malignant transformed cell model, and xenograft tumor models. We found that KCNJ15 was remarkably under-expressed during lung carcinogenesis and progression. High levels of DNA methylation led to low KCNJ15 expression in 3-MCA-induced malignantly transformed HBE cells. High expression of KCNJ15 was positively correlated with good survival prognosis in lung cancer patients. KCNJ15 overexpression significantly inhibited the growth, invasion, and migration of lung cancer cells both in vitro and in vivo. Knockdown of KCNJ15 resulted in an opposite phenotype. KCNJ15 regulated the Hippo pathway by activating YAP phosphorylation and inhibiting YAP expression. There was a significant protein-protein interaction between KCNJ15 and the G protein subunit beta 1 (GNB1). GNB1 overexpression effectively reduced the effect of KCNJ15 on Hippo pathway. Our data demonstrated that KCNJ15, as a novel epigenetic silencing tumor suppressor, regulates cell growth, invasion, and migration by interaction with GNB1 protein mediating the Hippo-YAP signaling pathway during chemical-induced lung carcinogenesis and progression. It provides novel insights into epigenetic regulation mechanism during carcinogenesis induced by environmental pollutants.

An epigenetic memory at the CYP1A gene in cancer-resistant, pollution-adapted killifish

Human exposure to polycyclic aromatic hydrocarbons (PAH) is a significant public health problem that will worsen with a warming climate and increased large-scale wildfires. Here, we characterize an epigenetic memory at the cytochrome P450 1 A (CYP1A) gene in wild Fundulus heteroclitus that have adapted to chronic, extreme PAH pollution. In wild-type fish, CYP1A is highly induced by PAH. In PAH-tolerant fish, CYP1A induction is blunted. Since CYP1A metabolically activates PAH, this memory protects these fish from PAH-mediated cancer. However, PAH-tolerant fish reared in clean water recover CYP1A inducibility, indicating a non-genetic effect. We observed epigenetic control of this reversible memory of generational PAH stress in F1 PAH-tolerant embryos. We detected a bivalent domain in the CYP1A promoter enhancer comprising both activating and repressive histone post-translational modifications. Activating modifications, relative to repressive ones, showed greater increases in response to PAH in sensitive embryos, relative to tolerant, consistent with greater gene activation. PAH-tolerant adult fish showed persistent induction of CYP1A long after exposure cessation, which is consistent with defective CYP1A shutoff. These results indicate that PAH-tolerant fish have epigenetic protection against PAH-induced cancer in early life that degrades in response to continuous gene activation.

Prediction of the Survival Status, Immunotherapy Response, and Medication of Lung Adenocarcinoma Patients Based on Hypoxia- and Apoptosis-Related Genes

To predict patient survival prognosis, we aimed to establish a novel set of gene features associated with hypoxia and apoptosis. RNA-seq and clinical data of LUAD were sourced from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, while hypoxia and apoptosis-related genes were obtained from the Molecular Signatures Database (MsigDB). A 13-gene-prognostic model incorporating hypoxia and apoptosis genes was developed using univariate/multivariate Cox regression, Nonnegative Matrix Factorization (NMF) clustering, and LASSO regression. Patients were divided into high-risk (HR) and low-risk (LR) groups according to the median risk score. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed distinct biological processes between HR and LR groups, including hormone regulation and lipid metabolism pathways. Single sample gene set enrichment analysis (ssGSEA) indicated elevated cell infiltration levels of Neutrophils and T_helper_cells in the LR group, while NK cells and Th1cells were higher in the HR group. Immunophenoscore (IPS) and tumor immune dysfunction and exclusion (TIDE) analyses suggested potential benefits of immunotherapy for LR group patients. In conclusion, this prognostic feature integrating hypoxia- and apoptosis-related genes offers insights into predicting survival, immune status, and treatment response in LUAD patients, paving the way for personalized treatment strategies.

Rewiring the nexus between urban traffic pollution-derived polycyclic aromatic hydrocarbon exposure and DNA injury via urinary metabolomics

Urban road traffic environmental stress impacts outdoor population health, with oxidative damage serving as an early indicator of xenobiotic exposure. Polycyclic aromatic hydrocarbons (PAHs) as priority carcinogens pose significant public health burden, yet knowledge remains limited regarding the endogenous metabolic alternations associated with oxidative DNA injury. This cross-sectional study focused on the cohort consisting of 109 sanitation workers ("traffic exposure group") and 112 demographics-matched common residents ("controls") in South China. The goal was to elucidate the occurrence of internal exposure to nine hydroxyl PAHs, and the interrelations with oxidative DNA damage (indicated by 8-hydroxy-2'-deoxyguanosine, 8-OHdG) by linear mixed-effect regression model. T-test and orthogonal partial least squares discriminant analysis were used to determine differential metabolites in non-targeted metabolomics. Results revealed outdoor workers suffered from the heavier PAH exposure burden and exhibited a stronger dose-dependent correlation with 8-OHdG, evidenced by the higher regression coefficient (0.244, 95% CI: 0.154-0.334) than controls (0.203, 95% CI: 0.079-0.328). In total 42 differential endogenous metabolites witnessed significant expression under traffic emission scenario, mainly implicated in phenylalanine, tyrosine and tryptophan biosynthesis. The down-expressed uric acid was the unique metabolite that inversely correlated with the increased intake of ∑8PAH especially in cases. Partially attributed to the traffic-derived PAHs, the dysregulated amino acid, nicotinamide, purine, and steroid hormones metabolic pathways encompassing 11 metabolites were determined as underlying biomarkers in mediating DNA damage. Notably, our findings proposed uric acid may act as a potential antioxidant, as evidenced by the negative correlation with 8-OHdG. The study illustrates outcomes of metabolomics can collaboratively indicate DNA oxidative damage caused by PAHs linked to urban traffic exposure, which holds significant implications for future toxicological research.

A Natural Chalcone Cardamonin Inhibited Transformation of Aryl Hydrocarbon Receptor Through Binding to the Receptor Competitively

SCOPE

Chalcones are widely present in most plants and have various health beneficial functions. This study investigates the suppressive effect of 13 natural and synthetic chalcones on transformation of aryl hydrocarbon receptor (AhR) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3-methylcholanthrene (3-MC) in a cell-free system, Hepa-1c1c7 cells, and liver of ICR mice.

METHODS AND RESULTS

In the cell-free system, cardamonin dose-dependently inhibits AhR transformation. Chalcones with substitution on 2' and/or 6' position is important for the suppressive effect, while the substitution on 4' position is negatively for the effect. Moreover, cardamonin and 2'-hydroxychalcone competitively inhibit the binding of [3H]-3-MC to the AhR. In Hepa-1c1c7 cells, cardamonin inhibits AhR transformation and expression of cytochrome P4501A1 (CYP1A1) in a dose-dependent manner through suppressing TCDD-induced phosphorylation of both AhR and AhR nuclear translocator, heterodimerization of them, and nuclear translocation of AhR. In the liver of mice, oral administered cardamonin also inhibits 3-MC-induced AhR translocation and expression of CYP1A1.

CONCLUSION

Among used chalcones, a natural chalcone cardamonin competitively binds to AhR and suppresses its transformation. Thus, cardamonin is an effective food factor for suppression of the dioxin-caused biochemical alterations and toxicities.

An epigenetic memory at the CYP1A gene in cancer-resistant, pollution-adapted killifish

Human exposure to polycyclic aromatic hydrocarbons (PAH) is a significant and growing public health problem. Frequent, high dose exposures are likely to increase due to a warming climate and increased frequency of large-scale wildfires. Here, we characterize an epigenetic memory at the cytochrome P450 1A (CYP1A) gene in a population of wild Fundulus heteroclitus that has adapted to chronic, extreme PAH pollution. In wild-type fish, CYP1A is highly induced by PAH. In PAH-tolerant fish, CYP1A induction is blunted. Since CYP1A metabolically activates PAH, this memory protects these fish from PAH-mediated cancer. However, PAH-tolerant fish reared in clean water recover CYP1A inducibility, indicating that blunted induction is a non-genetic memory of prior exposure. To explore this possibility, we bred depurated wild fish from PAH-sensitive and - tolerant populations, manually fertilized exposure-naïve embryos, and challenged them with PAH. We observed epigenetic control of the reversible memory of generational PAH stress in F1 PAH-tolerant embryos. Specifically, we observed a bivalent domain in the CYP1A promoter enhancer comprising both activating and repressive histone post-translational modifications. Activating modifications, relative to repressive ones, showed greater increases in response to PAH in sensitive embryos, relative to tolerant, consistent with greater gene activation. Also, PAH-tolerant adult fish showed persistent induction of CYP1A long after exposure cessation, which is consistent with defective CYP1A shutoff and recovery to baseline. Since CYP1A expression is inversely correlated with cancer risk, these results indicate that PAH-tolerant fish have epigenetic protection against PAH-induced cancer in early life that degrades in response to continuous gene activation.

Polycyclic aromatic hydrocarbon and its adducts in peripheral blood: Gene and environment interaction among Chinese population

BACKGROUND

Benzo(a)pyrene (B[a]P) is the most widely concerned polycyclic aromatic hydrocarbons (PAHs), which metabolizes benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) in vivo to produce carcinogenic effect on the body. Currently, there is limited research on the role of the variation of metabolic enzymes in this process.

METHODS

We carried out a study including 752 participants, measured the concentrations of 16 kinds PAHs in both particle and gaseous phases, urinary PAHs metabolites, leukocyte BPDE-DNA adduct and serum BPDE- Albumin (BPDE-Alb) adduct, and calculated daily intake dose (DID) to assess the cumulative exposure of PAHs. We conducted single nucleotide polymorphism sites (SNPs) of metabolic enzymes, explored the exposure-response relationship between the levels of exposure and BPDE adducts using multiple linear regression models.

RESULT

Our results indicated that an interquartile range (IQR) increase in B[a]P, PAHs, BaPeq, 1-hydroxypyrene (1-OHP), 1-hydroxynaphthalene (1-OHNap) and 2-hydroxynaphthalene (2-OHNap) were associated with 26.53 %, 24.24 %, 28.15 %, 39.15 %, 12.85 % and 14.09 % increase in leukocyte BPDE-DNA adduct (all P < 0.05). However, there was no significant correlation between exposure with serum BPDE-Alb adduct (P > 0.05). Besides, we also found the polymorphism of CYP1A1(Gly45Asp), CYP2C9 (Ile359Leu), and UGT1A1(downstream) may affect BPDE adducts level.

CONCLUSION

Our results indicated that leukocyte BPDE-DNA adduct could better reflect the exposure to PAHs. Furthermore, the polymorphism of CYP1A1, CYP2C9 and UGT1A1affected the content of BPDE adducts.

Genotoxic effects of marine pollutants on coastal meso-zooplankton populations - A mini-review

Meso-zooplankton plays a vital role in maintaining healthy marine ecosystems, and some of the taxa provide biological indications for the monitoring of environmental and climate change. Recently, several newly emerging stressors were shown to impact marine and coastal meso-zooplankton in some ways. Marine organisms' genomic core, tightly packed with high-level integrity, can be damaged by anthropogenic activities in coastal zones worldwide and impact their integrity. Genomic integrity loss leads to a cascade of effects on the destruction of the food chain sequences, from primary producers to higher invertebrates. Therefore, monitoring genomic integrity loss using ecotoxicological approaches that focus on genetic changes appears to be a suitable approach. A literature review shows that different stressors severely impact genomic integrity through DNA damage at different concentrations and exposure times. Contaminated sediments also strongly impact the genomic integrity of estuaries and adjacent coastal meso-zooplankton communities.

Attenuation of Polycyclic Aromatic Hydrocarbon (PAH)-Induced Carcinogenesis and Tumorigenesis by Omega-3 Fatty Acids in Mice In Vivo

Lung cancer is the leading cause of cancer death worldwide. Polycyclic aromatic hydrocarbons (PAHs) are metabolized by the cytochrome P450 (CYP)1A and 1B1 to DNA-reactive metabolites, which could lead to mutations in critical genes, eventually resulting in cancer. Omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are beneficial against cancers. In this investigation, we elucidated the mechanisms by which omega-3 fatty acids EPA and DHA will attenuate PAH-DNA adducts and lung carcinogenesis and tumorigenesis mediated by the PAHs BP and MC. Adult wild-type (WT) (A/J) mice, Cyp1a1-null, Cyp1a2-null, or Cyp1b1-null mice were exposed to PAHs benzo[a]pyrene (BP) or 3-methylcholanthrene (MC), and the effects of omega-3 fatty acid on PAH-mediated lung carcinogenesis and tumorigenesis were studied. The major findings were as follows: (i) omega-3 fatty acids significantly decreased PAH-DNA adducts in the lungs of each of the genotypes studied; (ii) decreases in PAH-DNA adduct levels by EPA/DHA was in part due to inhibition of CYP1B1; (iii) inhibition of soluble epoxide hydrolase (sEH) enhanced the EPA/DHA-mediated prevention of pulmonary carcinogenesis; and (iv) EPA/DHA attenuated PAH-mediated carcinogenesis in part by epigenetic mechanisms. Taken together, our results suggest that omega-3 fatty acids have the potential to be developed as cancer chemo-preventive agents in people.

Particulate polycyclic aromatic hydrocarbons in rural households burning solid fuels in Xuanwei County, Southwest China: occurrence, size distribution, and health risks

The study is about the size distribution and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor environment of Xuanwei, Southwest China particle samples were collected by Anderson 8-stage impactor which was used to gather particle samples to nine size ranges. Size-segregated samples were collected in indoor from a rural village in Xuanwei during the non-heating and heating seasons. The results showed that the total concentrations of the indoor particulate matter (PM) were 757 ± 60 and 990 ± 78 μg/m3 in non-heating and heating seasons, respectively. The total concentration of indoor PAHs reached to 8.42 ± 0.53 μg/m3 in the heating season, which was considerably greater than the concentration in the non-heating season (2.85 ± 1.72 μg/m3). The size distribution of PAHs showed that PAHs were mainly enriched in PMs with the diameter <1.1 μm. The diagnostic ratios (DR) and principal component analysis (PCA) showed that coal and wood for residential heating and cooking were the main sources of indoor PAHs. The results of the health risk showed that the total deposition concentration (DC) in the alveolar region (AR) was 0.25 and 0.68 μg/m3 in the non-heating and heating seasons respectively. Throughout the entire sampling periods, the lifetime cancer risk (R) based on DC of children and adults varied between 3.53 ×10-5 to 1.79 ×10-4. During the heating season, the potential cancer risk of PAHs in adults was significant, exceeding 10-4, with a rate of 96%.

PM2.5 leads to adverse pregnancy outcomes by inducing trophoblast oxidative stress and mitochondrial apoptosis via KLF9/CYP1A1 transcriptional axis

Epidemiological studies have demonstrated that fine particulate matter (PM2.5) is associated with adverse obstetric and postnatal metabolic health outcomes, but the mechanism remains unclear. This study aimed to investigate the toxicological pathways by which PM2.5 damaged placental trophoblasts in vivo and in vitro. We confirmed that PM2.5 induced adverse gestational outcomes such as increased fetal mortality rates, decreased fetal numbers and weight, damaged placental structure, and increased apoptosis of trophoblasts. Additionally, PM2.5 induced dysfunction of the trophoblast cell line HTR8/SVneo, including in its proliferation, apoptosis, invasion, migration and angiogenesis. Moreover, we comprehensively analyzed the transcriptional landscape of HTR8/SVneo cells exposed to PM2.5 through RNA-Seq and observed that PM2.5 triggered overexpression of pathways involved in oxidative stress and mitochondrial apoptosis to damage HTR8/SVneo cell biological functions through CYP1A1. Mechanistically, PM2.5 stimulated KLF9, a transcription factor identified as binding to CYP1A1 promoter region, which further modulated the CYP1A1-driven downstream phenotypes. Together, this study demonstrated that the KLF9/CYP1A1 axis played a crucial role in the toxic progression of PM2.5 induced adverse pregnancy outcomes, suggesting adverse effects of environmental pollution on pregnant females and putative targeted therapeutic strategies.

Protective Effects of Piceatannol on DNA Damage in Benzo[a]pyrene-Induced Human Colon Epithelial Cells

Evidence shows that the dietary intake of polycyclic aromatic hydrocarbons (PAHs) from food processing induces the cellular DNA damage response and leads to the development of colorectal cancer (CRC). Therefore, protecting from cellular DNA damage might be an effective strategy in preventing CRC. Benzo[a]pyrene (B[a]P) was used as a CRC initiator in the present study. Compared with other stilbenoids, piceatannol (PIC) showed the most effective inhibition of B[a]P-induced cytochrome P450 1B1 (CYP1B1) protein expression in NCM460 normal human colon epithelial cells. PIC treatment alleviated DNA migration and enhanced the expression of DNA-repair-related proteins, including histone 2AX (H2AX), checkpoint kinase 1 (Chk1), and p53, in B[a]P-induced NCM460 cells. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA) revealed that PIC exerted antioxidative effects on NCM460 cells by increasing the glutathione (GSH) content and scavenging the excess intracellular reactive oxygen species (ROS) induced by B[a]P. Furthermore, PIC suppressed B[a]P-induced CYP1B1 protein expression and stimulated miR-27b-3p expression. The upregulation of phase II detoxification enzymes, such as nicotinamide adenine dinucleotide phosphate (NADPH) and quinone oxidoreductase 1 (NQO1), and the antioxidative enzyme, heme oxygenase 1 (HO-1), via the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was observed in the PIC-treated group. Our results suggest that PIC is a potential CRC-blocking agent due to its ability to alleviate DNA damage, decrease intracellular ROS production, modulate the metabolism and detoxification of B[a]P, and activate the Nrf2 signaling pathway in B[a]P-induced NCM460 cells.

Network pharmacology-based analysis of heat clearing and detoxifying drug JC724 on the treatment of colorectal cancer

BACKGROUND

Heat-clearing and detoxifying drugs has protective effect on colorectal cancer (CRC). Given the complicated features of Traditional Chinese medicine formulas, network pharmacology is an effective approach for studying the multiple interactions between drugs and diseases.

AIM

To systematically explore the anticancer mechanism of heat-clearing and detoxifying drug JC724.

METHODS

This study obtained the active compounds and their targets in JC724 from Traditional Chinese Medicine System Pharmacology Database. In addition, the CRC targets were obtained from Drugbank, TTD, DisGeNET and GeneCards databases. We performed transcriptome analysis of differentially expressed genes in CRC treated with JC724. Venn diagram was used to screen the JC724-CRC intersection targets as candidate targets. Core targets were selected by protein-protein interaction network and herb ingredient-target-disease network analysis. The functional and pathway of core targets were analysed by enrichment analysis.

RESULTS

We found 174 active ingredients and 283 compound targets from JC724. 940 CRC-related targets were reserved from the four databases and 304 CRC differentially expressed genes were obtained by transcriptome analysis. We constructed the network and found that the five core ingredients were quercetin, β Beta sitosterol, wogonin, kaempferol and baicalein. The core JC724-CRC targets were CYP1A1, HMOX1, CXCL8, NQO1 and FOSL1. JC724 acts on multiple signaling pathways associated with CRC, including the Nrf2 signaling pathway, oxidative stress, and the IL-17 signaling pathway.

CONCLUSION

In this study, we systematically analyzed the active ingredients, core targets and main mechanisms of JC724 in the treatment of CRC. This study could bring a new perspective to the heat-clearing and detoxifying therapy of CRC.

Butyrate Enhances γ-H2AX Induced by Benzo[a]pyrene

Benzo[a]pyrene (BaP) is known to form DNA adduct following metabolic activation, which causes phosphorylation of histone H2AX (γ-H2AX). Recent studies have shown that histone deacetylase (HDAC) inhibitors enhanced BaP-induced CYP1A1 gene expression. In this study, we examined the relationship between the HDAC inhibitor-augmented metabolic activation and BaP-induced γ-H2AX. Sodium butyrate (SB), a typical HDAC inhibitor, enhanced BaP-induced γ-H2AX. The enhanced DNA damage was further confirmed by biased sinusoidal field gel electrophoresis, which detects DNA double-strand breaks. SB remarkably augmented BaP-induced CYP1A1 gene expression, and CYP1A1-overexpressing cells showed elevated generation of γ-H2AX. Furthermore, SB enhanced intracellular oxidation after treatment with BaP. These results suggested that SB-induced CYP1A1 upregulation facilitated BaP metabolism, which might result in excess DNA adducts or oxidative DNA damages, leading to augmentation of γ-H2AX.

Metabolomics coupled with network pharmacology study on the protective effect of Keguan-1 granules in LPS-induced acute lung injury

CONTEXT

Keguan-1 (KG-1) plays a vital role in enhancing the curative effects, improving quality of life, and reducing the development of acute lung injury (ALI).

OBJECTIVE

To unravel the protective effect and underlying mechanism of KG-1 against ALI.

MATERIALS AND METHODS

C57BL/6J mice were intratracheally instilled with lipopolysaccharide to establish the ALI model. Then, mice in the KG-1 group received a dose of 5.04 g/kg for 12 h. The levels of proinflammatory cytokines, chemokines, and pathological characteristics were determined to explore the effects of KG-1. Next, untargeted metabolomics was used to identify the differential metabolites and involved pathways for KG-1 anti-ALI. Network pharmacology was carried out to predict the putative active components and drug targets of KG-1 anti-ALI.

RESULTS

KG-1 significantly improved the levels of TNF-α (from 2295.92 ± 529.87 pg/mL to 1167.64 ± 318.91 pg/mL), IL-6 (from 4688.80 ± 481.68 pg/mL to 3604.43 ± 382.00 pg/mL), CXCL1 (from 4361.76 ± 505.73 pg/mL to 2981.04 ± 526.18 pg/mL), CXCL2 (from 5034.09 ± 809.28 pg/mL to 2980.30 ± 747.63 pg/mL), and impaired lung histological damage. Untargeted metabolomics revealed that KG-1 significantly regulated 12 different metabolites, which mainly related to lipid, amino acid, and vitamin metabolism. Network pharmacology showed that KG-1 exhibited anti-ALI effects through 17 potentially active components acting on seven putative drug targets to regulate four metabolites.

DISCUSSION AND CONCLUSIONS

This work elucidated the therapeutic effect and underlying mechanism by which KG-1 protects against ALI from the view of the metabolome, thus providing a scientific basis for the usage of KG-1.

Impact of e-cigarette aerosol on primary human alveolar epithelial type 2 cells

Electronic cigarettes (e-cigarettes) are designed to simulate combustible cigarette smoking and to aid in smoking cessation. Although the number of e-cigarette users has been increasing, the potential health impacts and biological effects of e-cigarettes are still not fully understood. Previous research has focused on the biological effects of e-cigarettes on lung cancer cell lines and distal airway epithelial cells; however, there have been few published studies on the effect of e-cigarettes on primary lung alveolar epithelial cells. The primary purpose of this study was to investigate the direct effect of e-cigarette aerosol on primary human lung alveolar epithelial type 2 (AT2) cells, both alone and in the presence of viral infection. The Melo-3 atomizer caused direct AT2 cell toxicity, whereas the more popular Juul pod's aerosol did not have a detectable cytotoxic effect on AT2 cells. Juul nicotine aerosol also did not increase short-term susceptibility to viral infection. However, 3 days of exposure upregulated genes central to the generation of reactive oxygen species, lipid peroxidation, and carcinogen metabolism and downregulated key innate immune system genes related to cytokine and chemokine signaling. These findings have implications for the potentially injurious impact of long-term use of popular low-power e-cigarette pods on the human alveolar epithelium. Gene expression data might be an important endpoint for evaluating the potential harmful effects of vaping devices that do not cause overt toxicity.

Establishment of cytochrome P450 1a gene-knockout Javanese medaka, Oryzias javanicus, which distinguishes toxicity modes of the polycyclic aromatic hydrocarbons, pyrene and phenanthrene

Cytochrome P450 1a (Cyp1a) is an important enzyme for metabolism of organic pollutants. To understand its reaction to polycyclic aromatic hydrocarbons (PAHs), we knocked out this gene in a marine model fish, Javanese medaka, Oryzias javanicus, using the CRISPR/Cas 9 system. A homozygous mutant (KO) strain with a four-base deletion was established using an environmental DNA (eDNA)-based genotyping technique. Subsequently, KO, heterozygous mutant (HT), and wild-type (WT) fish were exposed to model pollutants, pyrene and phenanthrene, and survivorship and swimming behavior were analyzed. Compared to WT, KO fish were more sensitive to pyrene, suggesting that Cyp1a transforms pyrene into less toxic metabolites. Conversely, WT fish were sensitive to phenanthrene, suggesting that metabolites transformed by Cyp1a are more toxic than the original compound. HT fish showed intermediate results. Thus, comparative use of KO and WT fish can distinguish modes of pollutant toxicity, providing a deeper understanding of fish catabolism of environmental pollutants.

Alterations of DNA methylation and mRNA levels of CYP1A1, GSTP1, and GSTM1 in human bronchial epithelial cells induced by benzo[a]pyrene

Benzo[a]pyrene (B[a]P) is a known human carcinogen and plays a major function in the initiation of lung cancer at its first proximity. However, the underlying molecular mechanisms are less well understood. In this study, we investigated the impact of B[a]P treatment on the DNA methylation and mRNA levels of CYP1A1, GSTP1, and GSTM1 in human bronchial epithelial cells (16HBEs), and provide scientific evidence for the mechanism study on the carcinogenesis of B[a]P. We treated 16HBEs with DMSO or concentrations of B[a]P at 1, 2, and 5 mmol/L for 24 h, observed the morphological changes, determined the cell viability, DNA methylation, and mRNA levels of CYP1A1, GSTP1, and GSTM1. Compared to the DMSO controls, B[a]P treatment had significantly increased the neoplastic cell number and cell viability in 16HBEs at all three doses (1, 2, and 5 mmol/L), and had significantly reduced the CYP1A1 and GSTP1 DNA promoter methylation levels. Following B[a]P treatment, the GSTM1 promoter methylation level in 16HBEs was profoundly reduced at low dose group compared to the DMSO controls, yet it was significantly increased at both middle and high dose groups. The mRNA levels of CYP1A1, GSTP1, and GSTM1 were significantly decreased in 16HBEs following B[a]P treatment at all three doses. The findings demonstrate that B[a]P promoted cell proliferation in 16HBEs, which was possibly related to the altered DNA methylations and the inhibited mRNA levels in CYP1A1, GSTP1, and GSTM1.

MOF-74/polystyrene-derived Ni-doped hierarchical porous carbon for structure-oriented extraction of polycyclic aromatic hydrocarbons and their metabolites from human biofluids

Polycyclic aromatic hydrocarbons (PAHs), as a major source that significantly increase the risk of developing lung cancer, severely jeopardize public health in modern society. The analysis of PAHs and their metabolites (hydroxylated PAHs, OH-PAHs) is important for biomonitoring and exposure assessment. However, due to the difference in their physico-chemical properties and matrix interference, realizing high-performance extraction of both PAHs and OH-PAHs is still a challenge. Herein, a nickel-doped hierarchical porous carbon (Ni/HPC) is synthesized by carbonizing the polystyrene (PS) infiltrated metal-organic frameworks (MOF-74(Ni)). The obtained Ni/HPC exhibits hierarchical pores and evenly distributed Ni atoms, providing efficient diffusion pathways and adsorption sites. The custom Ni/HPC-coated solid-phase microextraction (SPME) fiber shows superior enrichment capabilities for PAHs and their metabolites under various interfering conditions, verifying its practicability in real sample analysis. The proposed method provides a new strategy to synthesize carbon-based adsorbents that achieves matrix-resistant enrichment of PAHs and OH-PAHs, which simplifies the related sample preparation process for environmental analysis and clinical diagnosis.

Attenuation of Polycyclic Aromatic Hydrocarbon (PAH)-Mediated Pulmonary DNA Adducts and Cytochrome P450 (CYP)1B1 by Dietary Antioxidants, Omega-3 Fatty Acids, in Mice

Numerous human and animal studies have reported positive correlation between carcinogen-DNA adduct levels and cancer occurrence. Therefore, attenuation of DNA adduct levels would be expected to suppress tumorigenesis. In this investigation, we report that the antioxidants omega 3-fatty acids, which are constituents of fish oil (FO), significantly decreased DNA adduct formation by polycyclic aromatic hydrocarbons (PAHs). B6C3F1 male mice were fed an FO or corn oil (CO) diet, or A/J male mice were pre-fed with omega-3 fatty acids eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA). While the B6C3F1 mice were administered two doses of a mixture of seven carcinogenic PAHs including benzo(a)pyrene (BP), the A/J mice were treated i.p. with pure benzo[a]pyrene (BP). Animals were euthanized after 1, 3, or 7 d after PAH treatment. DNA adduct levels were measured by the ³²P-postlabeling assay. Our results showed that DNA adduct levels in the lungs of mice 7 d after treatment were significantly decreased in the FO or EPA/DHA groups compared with the CO group. Interestingly, both qPCR and Western blot analyses revealed that FO, DHA and EPA/DHA significantly decreased the expression of cytochrome P450 (CYP) 1B1. CYP1B1 plays a critical role in the metabolic activation of BP to DNA-reactive metabolites. qPCR also showed that the expression of some metabolic and DNA repair genes was induced by BP and inhibited by FO or omega-3 fatty acids in liver, but not lung. Our results suggest that a combination of mechanism entailing CYP1B1 inhibition and the modulation of DNA repair genes contribute to the attenuation of PAH-mediated carcinogenesis by omega 3 fatty acids.

Mutagenicity risk prediction of PAH and derivative mixtures by in silico simulations oriented from CYP compound I-mediated metabolic activation

PAHs and their derivatives are the main sources of mutagenicity and carcinogenicity in airborne particular matter and cause serious public health and environmental problems. Risk assessment is challenging due to the mixed nature and deficiency of toxicity data of most PAHs and their derivatives. Cytochrome P450 enzymes (CYPs) play important roles in PAH-induced carcinogenicity via metabolic activation, and CYP conformations with compound I structures strongly influence metabolic sites and metabolite species. In this study, complexes of BaP with CYP1A1, CYP1B1 or CYP2C19 compound I were successfully simulated by QM/MM methods and verified by metabolic clearance, and the mutagenicity of chemicals was then predicted by the BaP-7,8-epoxide-related metabolic conformation fitness (MCF) approach, which was validated by Ames tests, showing satisfying accuracy (R² = 0.46-0.66). Furthermore, a prediction model of the mutagenicity risk of PAH and derivative mixtures was established based on the relative potential factor (RPF) approach and the RPF calculated from the mathematical relationship between the minimum MCF (MCF_min) and RPF, which was successfully validated by the mutagenesis of PAH and derivative mixture mimic-simulating PM2.5 samples collected in eastern China. This study provides fast reliable tools for assessing risk of the complex components of environmental PAHs and their derivatives.

Molecular mechanisms of pulmonary carcinogenesis by polycyclic aromatic hydrocarbons (PAHs): Implications for human lung cancer

Lung cancer has the second highest incidence and highest mortality compared to all other cancers. Polycyclic aromatic hydrocarbon (PAH) molecules belong to a class of compounds that are present in tobacco smoke, diesel exhausts, smoked foods, as well as particulate matter (PM). PAH-derived reactive metabolites are significant contributors to lung cancer development. The formation of these reactive metabolites entails metabolism of the parent PAHs by cytochrome P4501A1/1B1 (CYP1A1/1B1) and epoxide hydrolase enzymes. These reactive metabolites then react with DNA to form DNA adducts, which contribute to key gene mutations, such as the tumor suppressor gene, p53 and are linked to pulmonary carcinogenesis. PAH exposure also leads to upregulation of CYP1A1 transcription by binding to the aryl hydrocarbon receptor (AHR) and eliciting transcription of the CYP1A1 promoter, which comprises specific xenobiotic-responsive element (XREs). While hepatic and pulmonary CYP1A1/1B1 metabolize PAHs to DNA-reactive metabolites, the hepatic CYP1A2, however, may protect against lung tumor development by suppressing both liver and lung CYP1A1 enzymes. Further analysis of these enzymes has shown that PAH-exposure also induces sustained transcription of CYP1A1, which is independent of the persistence of the parent PAH. CYP1A2 enzyme plays an important role in the sustained induction of hepatic CYP1A1. PAH exposure may further contribute to pulmonary carcinogenesis by producing epigenetic alterations. DNA methylation, histone modification, long interspersed nuclear element (LINE-1) activation, and non-coding RNA, specifically microRNA (miRNA) alterations may all be induced by PAH exposure. The relationship between PAH-induced enzymatic reactive metabolite formation and epigenetic alterations is a key area of research that warrants further exploration. Investigation into the potential interplay between these two mechanisms may lead to further understanding of the mechanisms of PAH carcinogenesis. These mechanisms will be crucial for the development of effective targeted therapies and early diagnostic tools.

Biological roles of cytochrome P450 1A1, 1A2, and 1B1 enzymes

Human cytochrome P450 enzymes (CYPs) play a critical role in various biological processes and human diseases. CYP1 family members, including CYP1A1, CYP1A2, and CYP1B1, are induced by aryl hydrocarbon receptors (AhRs). The binding of ligands such as polycyclic aromatic hydrocarbons activates the AhRs, which are involved in the metabolism (including oxidation) of various endogenous or exogenous substrates. The ligands that induce CYP1 expression are reported to be carcinogenic xenobiotics. Hence, CYP1 enzymes are correlated with the pathogenesis of cancers. Various endogenous substrates are involved in the metabolism of steroid hormones, eicosanoids, and other biological molecules that mediate the pathogenesis of several human diseases. Additionally, CYP1s metabolize and activate/inactivate therapeutic drugs, especially, anti-cancer agents. As the metabolism of drugs determines their therapeutic efficacy, CYP1s can determine the susceptibility of patients to some drugs. Thus, understanding the role of CYP1s in diseases and establishing novel and efficient therapeutic strategies based on CYP1s have piqued the interest of the scientific community.

A green analytical method for the analysis of polycyclic aromatic hydrocarbons in oral fluids from crack smokers

Aim: Develop and validate a method of solid-phase microextraction (SPME) and liquid chromatography to investigate three major polycyclic aromatic hydrocarbons (PAHs) in oral fluid. Results/Methodology: The extraction phase was exposed to 1.5 ml of diluted oral fluid under stirring at 1000 rpm for 60 min, at 70°C. Then, it was immersed in 200 μl of acetonitrile for 10 min at 25°C for desorption of the analytes. Linearity, absolute recovery, and inter- and intra-assay relative standard deviations and relative errors were 50-300 ng.ml^-1, ≥24% and ≤15% for all analytes, respectively. A full factorial design was used to SPME optimization. Discussion/Conclusion: The method is suitable for the exploratory analysis of some PAHs in the oral fluid of crack smokers.