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Reproductive Toxicology (Elmsford, N.Y.) Jun 2022The compound 3-methylcholanthrene (3-MC) is an environmental pollutant belonging to the PAHs, which reportedly have the potential to disrupt the endocrine systems of...
The compound 3-methylcholanthrene (3-MC) is an environmental pollutant belonging to the PAHs, which reportedly have the potential to disrupt the endocrine systems of animals. In the present study, 4-week-old male and female mice were given 3-MC through their diet at a dose of 0.5 mg/kg of chow for 6 weeks before pregnancy. The first filial (F) generation offspring of exposed or unexposed parental mice were sacrificed at the age of 5 or 10 weeks (F-5 W or F-10 W), and the potential effects on the F and F offspring were evaluated. The results showed that the serum and testicular testosterone (T) levels and the genes involved in T synthesis in F males and male F-5 W individuals born from female mice exposed to 3-MC were significantly decreased. In addition, histological analysis suggested that exposure to 3-MC significantly disrupted testicular morphology in F mice and in the offspring of female mice exposed to 3-MC. Further investigation revealed that genes involved in spermatogenesis, such as Phosphoglycerate kinase 2 (Pgk2), Glial cell derived neurotrophic factor (Gdnf), Myeloblastosis oncogene (Myb), DEAD box helicase 4 (Ddx4) and KIT proto-oncogene receptor tyrosine kinase (Kit), were suppressed in these mice. However, the adverse effects of parental 3-MC exposure on the adolescent mice were mitigated when they grew to adulthood, which was verified by studies on F-10 W mice. Our results suggest that female exposure to 3-MC has the potential to disrupt the endocrine system and spermatogenesis in male offspring; nevertheless, the adverse effects might be mitigated with age.
Topics: Adult; Animals; Endocrine System; Female; Humans; Male; Methylcholanthrene; Mice; Pregnancy; Prenatal Exposure Delayed Effects; Spermatogenesis; Testis
PubMed: 35487396
DOI: 10.1016/j.reprotox.2022.04.007 -
Journal of Toxicology and Environmental... Aug 2022L. is one of the most popular medicinal plants attributed to its beneficial properties on human health. However, few toxicogenetic studies have been carried out....
L. is one of the most popular medicinal plants attributed to its beneficial properties on human health. However, few toxicogenetic studies have been carried out. Therefore, the aim of this study was to examine the potential genotoxic/antigenotoxic and mutagenic/antimutagenic properties of oil, ethyl acetate and ethanolic extracts of L. fruits using the Ames and Umu assays, as well as micronucleus (MN) test. Extracts did not exert any significant mutagenic/genotoxic effects but provided protection against standard mutagenic and genotoxic agents including 2 nitrofluorene (2-NF) at 2.5 and 5 µg/ml; sodium azide at 5 and 10 µg/ml; 3-methylcholanthrene (3-MC) at 25 and 50 μg/ml; cyclophosphamide (CP) at 50 and 100 μg/ml; 4-nitroquinoline 1-oxide (4-NQO) at 0.05 µg/ml and 2-amino-anthracene (AA) at 0.2 µg/ml. Further, cytotoxicity and selectivity were examined on human hepatocarcinoma (HepG2), and MCF-7 breast cancer cell lines as well as a human normal-like fibroblast cell line (TelCOFS02MA) using MTT assay. Among all extracts, PF1 (ethanolic) showed the most significant selectivity index (SI) (HepG2:11.98; MCF7:4.83), which led to further investigations using an animal model. Oral administration of PF1 (125-1000 mg/kg b.w.) significantly decreased the number of micronucleated cells in CP -initiated (50 mg/kg b.w.) mice, while the number of micronucleated reticulocytes (MNRET), micronucleated polychromatic erythrocytes (MNPCE) or mitotic index (MI) were not markedly affected. Further, PF1 significantly enhanced catalase (CAT) and superoxide dismutase (SOD) activities in the livers and kidneys of these animals. The obtained results indicated the beneficial properties of L. fruits for use in therapy against harmful effects of genotoxic and mutagenic agents. However, while promising it should be noted that the obtained results are preliminary and need to be confirmed prior to therapeutic use.
Topics: Animals; Antimutagenic Agents; Cyclophosphamide; Fruit; Humans; Mice; Micronucleus Tests; Mutagens; Pistacia; Plant Extracts
PubMed: 35387576
DOI: 10.1080/15287394.2022.2057885 -
Toxicology Letters May 2022The aryl hydrocarbon receptor (AhR) is a receptor-type transcription factor that is crucial for endocrine disruption and carcinogenesis caused by environment chemicals....
The aryl hydrocarbon receptor (AhR) is a receptor-type transcription factor that is crucial for endocrine disruption and carcinogenesis caused by environment chemicals. Previous studies have indicated that certain intracellular signals are involved in AhR activation by their agonists, but the detailed mechanism remains unclear. In this study, we screened for important molecules for AhR activation using SCAD inhibitor kits. Among 164 kinase inhibitors listed in these kits, tyrphostin AG1024, commonly used as an inhibitor of insulin-like growth factor receptor (IGF1R) and insulin receptor (IR), was identified as a potent inhibitor of 3-methylcholanthrene (MC)-mediated AhR activation. We further investigated the mechanism by which AG1024 suppresses MC-mediated AhR activation. AG1024 decreased AhR-dependent luciferase activity, CYP1A1 gene expression, and its protein expression. However, when IGF1R siRNA and IR siRNA were used, AhR activation was slightly increased, in contrast to AG1024 treatment. In addition, AG1024 treatment downregulated the expression of AhR protein but not AhR gene, and decreased both nucleic and cytosolic AhR proteins. Therefore, AG1024 suppressed AhR activation by downregulating AhR protein expression. The molecular target of AG1024 remains unclear, and should be an important target for the regulation of AhR-dependent toxicity.
Topics: Cytochrome P-450 CYP1A1; Receptor, Insulin; Receptors, Aryl Hydrocarbon; Tyrphostins
PubMed: 35149128
DOI: 10.1016/j.toxlet.2022.02.003 -
International Journal of Molecular... Dec 2021Cutaneous squamous cell carcinoma (cSCC) accounts for 25% of cutaneous malignancies diagnosed in Caucasian populations. Surgical removal in combination with radiation...
Cutaneous squamous cell carcinoma (cSCC) accounts for 25% of cutaneous malignancies diagnosed in Caucasian populations. Surgical removal in combination with radiation and chemotherapy are effective treatments for cSCC. Nevertheless, the aggressive metastatic forms of cSCC still have a relatively poor patient outcome. Studies have linked actin cytoskeletal dynamics and the Wnt/β-catenin signaling pathway as important modulators of cSCC pathogenesis. Previous studies have also shown that the actin-remodeling protein Flightless (Flii) is a negative regulator of cSCC. The aim of this study was to investigate if the functional effects of Flii on cSCC involve the Wnt/β-catenin signaling pathway. Flii knockdown was performed using siRNA in a human late stage aggressive metastatic cSCC cell line (MET-1) alongside analysis of genetic murine models of 3-methylcholanthrene induced cSCC. Flii was increased in a MET-1 cSCC cell line and reducing Flii expression led to fewer PCNA positive cells and a concomitant reduction in cellular proliferation and symmetrical division. Knockdown of Flii led to decreased β-catenin and a decrease in the expression of the downstream effector of β-catenin signaling protein SOX9. 3-Methylcholanthrene (MCA)-induced cSCC in overexpressing mice showed increased markers of cancer metastasis including talin and keratin-14 and a significant increase in SOX9 alongside a reduction in Flii associated protein (Flap-1). Taken together, this study demonstrates a role for Flii in regulating proteins involved in cSCC proliferation and tumor progression and suggests a potential role for Flii in aggressive metastatic cSCC.
Topics: Animals; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Female; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Methylcholanthrene; Mice; Microfilament Proteins; Skin Neoplasms; Trans-Activators; Up-Regulation; Wnt Signaling Pathway
PubMed: 34948000
DOI: 10.3390/ijms222413203 -
Frontiers in Cellular and Infection... 2021The opportunistic pathogen is one of the few intestinal bacteria that has been consistently linked to colorectal cancer (CRC). This study aimed to identify novel...
OBJECTIVE
The opportunistic pathogen is one of the few intestinal bacteria that has been consistently linked to colorectal cancer (CRC). This study aimed to identify novel -induced pathways in colon epithelial cells that could further explain how contributes to CRC development.
DESIGN AND RESULTS
Transcription profiling of cultured CRC cells that were exposed to revealed the specific induction of oxidoreductase pathways. Most prominently, and genes that encode phase I biotransformation enzymes were responsible for the detoxification or bio-activation of toxic compounds. A common feature is that these enzymes are induced through the Aryl hydrocarbon receptor (AhR). Using the specific inhibitor CH223191, we showed that the induction of was dependent on the AhR both using multiple CRC cell lines as using wild-type C57bl6 mice colonized with . Furthermore, we showed that CYP1 could also be induced by other intestinal bacteria and that a yet unidentified diffusible factor from the secretome (SGS) induces CYP1A enzyme activity in an AhR-dependent manner. Importantly, priming CRC cells with SGS increased the DNA damaging effect of the polycyclic aromatic hydrocarbon 3-methylcholanthrene.
CONCLUSION
This study shows that gut bacteria have the potential to modulate the expression of biotransformation pathways in colonic epithelial cells in an AhR-dependent manner. This offers a novel theory on the contribution of intestinal bacteria to the etiology of CRC by modifying the capacity of intestinal epithelial or (pre-)cancerous cells to (de)toxify dietary components, which could alter intestinal susceptibility to DNA damaging events.
Topics: Animals; Biotransformation; Colorectal Neoplasms; Cytochrome P-450 CYP1A1; Epithelial Cells; Mice; Mice, Inbred C57BL; Receptors, Aryl Hydrocarbon; Streptococcus gallolyticus
PubMed: 34778104
DOI: 10.3389/fcimb.2021.740704 -
Archives of Toxicology Jan 2022Error-corrected sequences (ECSs) that utilize double-stranded DNA sequences are useful in detecting mutagen-induced mutations. However, relatively higher frequencies of...
Error-corrected sequences (ECSs) that utilize double-stranded DNA sequences are useful in detecting mutagen-induced mutations. However, relatively higher frequencies of G:C > T:A (1 × 10 bp) and G:C > C:G (2 × 10 bp) errors decrease the accuracy of detection of rare G:C mutations (approximately 10 bp). Oxidized guanines in single-strand (SS) overhangs generated after shearing could serve as the source of these errors. To remove these errors, we first computationally discarded up to 20 read bases corresponding to the ends of the DNA fragments. Error frequencies decreased proportionately with trimming length; however, the results indicated that they were not sufficiently removed. To efficiently remove SS overhangs, we evaluated three mechanistically distinct SS-specific nucleases (S1 Nuclease, mung bean nuclease, and RecJf exonuclease) and found that they were more efficient than computational trimming. Consequently, we established Jade-Seq™, an ECS protocol with S1 Nuclease treatment, which reduced G:C > T:A and G:C > C:G errors to 0.50 × 10 bp and 0.12 × 10 bp, respectively. This was probably because S1 Nuclease removed SS regions, such as gaps and nicks, depending on its wide substrate specificity. Subsequently, we evaluated the mutation-detection sensitivity of Jade-Seq™ using DNA samples from TA100 cells exposed to 3-methylcholanthrene and 7,12-dimethylbenz[a]anthracene, which contained the rare G:C > T:A mutation (i.e., 2 × 10 bp). Fold changes of G:C > T:A compared to the vehicle control were 1.2- and 1.3-times higher than those of samples without S1 Nuclease treatment, respectively. These findings indicate the potential of Jade-Seq™ for detecting rare mutations and determining the mutagenicity of environmental mutagens.
Topics: DNA; DNA Repair; High-Throughput Nucleotide Sequencing; Mutagens; Mutation
PubMed: 34767040
DOI: 10.1007/s00204-021-03185-y -
Journal of the American Heart... Oct 2021Background Hyperglycemia is associated with greater hematoma expansion (HE) and worse clinical prognosis after intracerebral hemorrhage (ICH). However, the clinical...
Background Hyperglycemia is associated with greater hematoma expansion (HE) and worse clinical prognosis after intracerebral hemorrhage (ICH). However, the clinical benefits of intensive glucose normalization remain controversial, and there are no approved therapies for reducing HE. The aryl hydrocarbon receptor (AHR) has been shown to participate in hyperglycemia-induced blood-brain barrier (BBB) dysfunction and brain injury after stroke. Herein, we investigated the role of AHR in hyperglycemia-induced HE in a male mouse model of ICH. Methods and Results CD1 mice (n=387) were used in this study. Mice were subjected to ICH by collagenase injection. Fifty percent dextrose was injected intraperitoneally 3 hours after ICH. AHR knockout clustered regularly interspaced short palindromic repeat was administered intracerebroventricularly to evaluate the role of AHR after ICH. A selective AHR inhibitor, 6,2',4'-trimethoxyflavone, was administered intraperitoneally 2 hours or 6 hours after ICH for outcome study. To evaluate the effect of AHR on HE, 3-methylcholanthrene, an AHR agonist, was injected intraperitoneally 2 hours after ICH. The results showed hyperglycemic ICH upregulated AHR accompanied by greater HE. AHR inhibition provided neurological benefits by restricting HE and preserving BBB function after hyperglycemic ICH. In vivo knockdown of AHR further limited HE and enhanced the BBB integrity. Hyperglycemia directly activated AHR as a physiological stimulus in vivo. The thrombospondin-1/transforming growth factor-β/vascular endothelial growth factor axis partly participated in AHR signaling after ICH, which inhibited the expressions of BBB-related proteins, ZO-1 and Claudin-5. Conclusions AHR may serve as a potential therapeutic target to attenuate hyperglycemia-induced hematoma expansion and to preserve the BBB in patients with ICH.
Topics: Animals; Cerebral Hemorrhage; Disease Models, Animal; Hematoma; Hyperglycemia; Male; Mice; Receptors, Aryl Hydrocarbon
PubMed: 34622690
DOI: 10.1161/JAHA.121.022701 -
Oncogene Nov 2021Cancer metastasis accounts for nearly 90% of all cancer deaths. Metastatic cancer progression requires both cancer cell migration to the site of the metastasis and...
Cancer metastasis accounts for nearly 90% of all cancer deaths. Metastatic cancer progression requires both cancer cell migration to the site of the metastasis and subsequent proliferation after colonization. However, it has long been recognized that cancer cell migration and proliferation can be uncoupled; but the mechanism underlying this paradox is not well understood. Here we report that TNFAIP8 (tumor necrosis factor-α-induced protein 8), a "professional" transfer protein of phosphoinositide second messengers, promotes cancer cell migration or metastasis but inhibits its proliferation or cancer growth. TNFAIP8-deficient mice developed larger tumors, but TNFAIP8-deficient tumor cells completely lost their ability to migrate toward chemoattractants and were defective in colonizing lung tissues as compared to wild-type counterparts. Mechanistically, TNFAIP8 served as a cellular "pilot" of tumor cell migration by locally amplifying PI3K-AKT and Rac signals on the cell membrane facing chemoattractant; at the same time, TNFAIP8 also acted as a global inhibitor of tumor cell growth and proliferation by regulating Hippo signaling pathway. These findings help explain the migration-proliferation paradox of cancer cells that characterizes many cancers.
Topics: Animals; Apoptosis Regulatory Proteins; Cell Line, Tumor; Cell Movement; Cell Proliferation; Diethylnitrosamine; Female; Fibrosarcoma; Gene Expression Regulation, Neoplastic; Hippo Signaling Pathway; Humans; Lung Neoplasms; Male; Methylcholanthrene; Mice; Phosphatidylinositol 3-Kinases; Skin Neoplasms
PubMed: 34608264
DOI: 10.1038/s41388-021-02035-6 -
Acta Pharmaceutica Sinica. B Sep 2021Aberrant activation of NLRP3 inflammasome in colonic macrophages strongly associates with the occurrence and progression of ulcerative colitis. Although targeting NLRP3...
Aberrant activation of NLRP3 inflammasome in colonic macrophages strongly associates with the occurrence and progression of ulcerative colitis. Although targeting NLRP3 inflammasome has been considered to be a potential therapy, the underlying mechanism through which pathway the intestinal inflammation is modulated remains controversial. By focusing on the flavonoid lonicerin, one of the most abundant constituents existed in a long historical anti-inflammatory and anti-infectious herb Thunb., here we report its therapeutic effect on intestinal inflammation by binding directly to enhancer of zeste homolog 2 (EZH2) histone methyltransferase. EZH2-mediated modification of H3K27me3 promotes the expression of autophagy-related protein 5, which in turn leads to enhanced autophagy and accelerates autolysosome-mediated NLRP3 degradation. Mutations of EZH2 residues (His129 and Arg685) indicated by the dynamic simulation study have found to greatly diminish the protective effect of lonicerin. More importantly, studies verify that lonicerin dose-dependently disrupts the NLRP3-ASC-pro-caspase-1 complex assembly and alleviates colitis, which is compromised by administration of EZH2 overexpression plasmid. Thus, these findings together put forth the stage for further considering lonicerin as an anti-inflammatory epigenetic agent and suggesting EZH2/ATG5/NLRP3 axis may serve as a novel strategy to prevent ulcerative colitis as well as other inflammatory diseases.
PubMed: 34589402
DOI: 10.1016/j.apsb.2021.03.011 -
Nature Cancer Feb 2021Complement has emerged as a component of tumor promoting inflammation. We conducted a systematic assessment of the role of complement activation and effector pathways in...
Complement has emerged as a component of tumor promoting inflammation. We conducted a systematic assessment of the role of complement activation and effector pathways in sarcomas. , and mice showed reduced susceptibility to 3-methylcholanthrene sarcomagenesis and transplanted sarcomas, whereas C1q and factor B deficiency had marginal effects. Complement 3a receptor (C3aR), but not C5aR1 and C5aR2, deficiency mirrored the phenotype of mice. C3 and C3aR deficiency were associated with reduced accumulation and functional skewing of tumor-associated macrophages, increased T cell activation and response to anti-PD-1 therapy. Transcriptional profiling of sarcoma infiltrating macrophages and monocytes revealed the enrichment of MHC II-dependent antigen presentation pathway in C3-deficient cells. In patients, C3aR expression correlated with a macrophage population signature and C3 deficiency-associated signatures predicted better clinical outcome. These results suggest that the lectin pathway and C3a/C3aR axis are key components of complement and macrophage-mediated sarcoma promotion and immunosuppression.
Topics: Animals; Complement Activation; Humans; Immunosuppression Therapy; Lectins; Mice; Monocytes; Receptor, Anaphylatoxin C5a; Receptors, Complement; Sarcoma
PubMed: 34505065
DOI: 10.1038/s43018-021-00173-0