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Perfluorooctane sulfonate (PFOS) is a widespread persistent organic pollutant. Both epidemiological survey and our previous in vivo study have revealed the associations between PFOS exposure and spermatogenesis disorder, while the underlying mechanisms are far from clear. In the present study, GC-2 cells, a mouse spermatocyte-derived cell line, was used to investigate the toxic effects of PFOS and its hypothetical mechanism of action. GC-2 cells were treated with PFOS (0, 50, 100 and 150 μM) for 24 h or 48 h. Results demonstrated that PFOS dose-dependently inhibited cell viability, induced G0/G1 cell cycle arrest and triggered apoptosis, which might be partly explained by the decrease in cyclin D1, PCNA and Bcl-2 protein expression; increase in Bax protein expression; and activation of caspase-9, -3. In addition, PFOS did not directly transactivate or repress estrogen receptors (ERs) in gene reporter assays, whereas the protein levels of both ERα and ERβ were significantly altered and the downstream ERK1/2 phosphorylation was inhibited by PFOS. Furthermore, pretreatment with specific ERα agonist PPT (1 μM) significantly attenuated the above PFOS-induced effects while specific ERβ agonist DPN (1 μM) accelerated them. These results suggest that PFOS may induce growth inhibition and apoptosis via non-genomic estrogen receptor/ERK1/2 signaling pathway in GC-2 cells, which provides a novel insight regarding the potential role of ERs in mediating PFOS-triggered spermatocyte toxicity., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Recently, celastrol has shown great potential for inducing apoptosis in acute myeloid leukemia cells, especially acute promyelocytic leukaemia cells. However, the mechanism is poorly understood. Metabolomics provides an overall understanding of metabolic mechanisms to illustrate celastrol's mechanism of action. We treated both nude mice bearing HL-60 cell xenografts in vivo and HL-60 cells as well as NB-4 cells in vitro with celastrol. Ultra-performance liquid chromatography coupled with mass spectrometry was used for metabolomics analysis of HL-60 cells in vivo and for targeted L-cysteine analysis in HL-60 and NB-4 cells in vitro. Flow cytometric analysis was performed to assess mitochondrial membrane potential, reactive oxygen species and apoptosis. Western blotting was conducted to detect the p53, Bax, cleaved caspase 9 and cleaved caspase 3 proteins. Celastrol inhibited tumour growth, induced apoptosis, and upregulated pro-apoptotic proteins in the xenograft tumour mouse model. Metabolomics showed that cysteine metabolism was the key metabolic alteration after celastrol treatment in HL-60 cells in vivo. Celastrol decreased L-cysteine in HL-60 cells. Acetylcysteine supplementation reversed reactive oxygen species accumulation and apoptosis induced by celastrol and reversed the dramatic decrease in the mitochondrial membrane potential and upregulation of pro-apoptotic proteins in HL-60 cells. In NB-4 cells, celastrol decreased L-cysteine, and acetylcysteine reversed celastrol-induced reactive oxygen species accumulation and apoptosis. We are the first to identify the involvement of a cysteine metabolism/reactive oxygen species/p53/Bax/caspase 9/caspase 3 pathway in celastrol-triggered mitochondrial apoptosis in HL-60 and NB-4 cells, providing a novel underlying mechanism through which celastrol could be used to treat acute myeloid leukaemia, especially acute promyelocytic leukaemia.

Male factor infertility affects one-sixth of couples worldwide, and non-obstructive azoospermia (NOA) is one of the most severe forms. In recent years there has been increasing evidence to implicate the participation of X chromosome in the process of spermatogenesis. To uncover the roles of X-linked multi-copy genes in spermatogenesis, we performed systematic analysis of X-linked gene copy number variations (CNVs) and Y chromosome haplogrouping in 447 idiopathic NOA patients and 485 healthy controls. Interestingly, the frequency of individuals with abnormal level copy of Variable charge, X-linked (VCX) was significantly different between cases and controls after multiple test correction (p = 5.10 × 10-5). To discriminate the effect of gain/loss copies in these genes, we analyzed the frequency of X-linked multi-copy genes in subjects among subdivided groups. Our results demonstrated that individuals with increased copy numbers of Nuclear RNA export factor 2 (NXF2) (p = 9.21 × 10-8) and VCX (p = 1.97 × 10-4) conferred the risk of NOA. In vitro analysis demonstrated that increasing copy number of VCX could upregulate the gene expression and regulate cell proliferation and apoptosis. Our study establishes a robust association between the VCX CNVs and NOA risk.

Polychlorinated biphenyls (PCBs) are widespread persistent environmental contaminants which have been shown to have reproductive toxicity and to disturb spermatogenesis. But the precise mechanism is not clear. A mouse pachytene spermatocyte-derived cell line, GC-2 cells were used in the present study to investigate the toxic effect of PCBs (Aroclor 1254) and explore the underlying molecular mechanism. Results showed that Aroclor 1254 inhibited cell proliferation, caused the arrest of cells in G0/G1 phase and induced apoptosis which might be partly explained by the decreased expression of Bcl-2 and cell cycle regulator cyclin D1 together with the activation of caspase-3. Besides, the treatment of Aroclor 1254 decreased the protein expression of estrogen receptor (ER)-α while increasing that of ERβ. Then the administration of selective ERα agonist PPT partly reversed Aroclor 1254-induced alteration in Bcl-2, caspase-3 and cyclin D1 protein expression while selective ERβ agonist DPN accelerated it. These results suggest that Aroclor 1254, working through ERα and ERβ, interferes with the expression of proteins involved in the balance between cellular apoptosis and proliferation., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Cytochrome P450 (CYP) 2A13 is mainly expressed in the respiratory system and has the ability to metabolize aflatoxin B(1) (AFB(1)). However, the role of CYP2A13-mediated AFB(1) metabolism and its consequences in human lung epithelial cell is not clear. Therefore, the objectives of this study were to investigate the significance of CYP2A13 in AFB(1)-induced cytotoxicity, DNA adducts, and apoptosis. To achieve these objectives, CYP2A13 was stably over-expressed in immortalized human bronchial epithelial BEAS-2B cells (B-2A13) and its significance in AFB(1)-induced cytotoxicity, DNA adducts, and apoptosis was compared to cells with stably expression of CYP1A2 (B-1A2), the predominant AFB(1) metabolizing enzyme in liver, as well as CYP2A6 (B-2A6) as controls. AFB(1) induced B-2A13 cytotoxicity and apoptosis in a dose- and time-dependent manner. The cytotoxic and apoptotic effects of AFB(1) were significantly remarkable in B-2A13 cells than those of B-1A2 and B-2A6 cells. The increased expression of pro-apoptotic proteins, such as C-PARP, C-caspase-3, and Bax, and decreased expression of anti-apoptotic proteins, such as caspase-3, Bcl-2, and p-Bad further confirmed the data of AFB(1)-induced cytotoxicity and apoptosis. Furthermore, increased DNA adduct was observed in B-2A13 after AFB(1) treatment as compared to B-1A2 cells and B-2A6 cells. Finally, treatment with nicotine, a competitor of AFB(1), and 8-methoxypsoralen (8-MOP), an inhibitor of CYP enzyme, further confirm the critical role of CYP2A13 in AFB(1)-induced cytotoxicity and apoptosis. Collectively, these findings suggest adverse effects of AFB(1) in respiratory diseases mediated by CYP2A13., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Biphasic dose-response relationship induced by environmental agents is often characterized with the effect of low-dose stimulation and high dose inhibition. Some studies showed that arsenite may induce cell proliferation and apoptosis via biphasic dose-response relationship in human cells; however, mechanisms underlying this phenomenon are not well understood. Our present study shows that, for human keratinocytes (HaCaT) cells, a low concentration of arsenite activates extracellular signal-regulated kinases (ERKs), which leads to up-regulation of nuclear factor κB (NF-κB) binding to DNA and to elevated, NF-κB-dependent expression of mot-2 (a p53 inhibitor) and survivin (an inhibitor of apoptosis). Activation of p53 is blocked, and neoplastic transformation is enhanced. Inhibition of ERKs reduces cell proliferation and neoplastic transformation. In contrast, a high concentration of arsenite activates c-Jun N-terminal kinases (JNKs), positive regulators of p53, by binding to p53 and preventing its murine double minute 2 (mdm2)-mediated degradation. The elevated levels of p53 lead to repair of DNA damage and apoptosis. Inhibition of JNKs increases DNA damage but decreases apoptosis. By identifying a mechanism whereby ERKs and JNKs-mediated regulation of the p53-survivin signal pathway is involved in the biphasic effects of arsenite on human keratinocytes, our data expand understanding of arsenite-induced cell proliferation, neoplastic transformation, DNA damage, and apoptosis., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

When cells encounter genotoxic stress, sensors for DNA lesions stabilize and activate p53; the signals involved, however, are largely unclear. Inorganic arsenite is a ubiquitous environmental contaminant associated with an increased risk of lung and skin damage and cancer. Although DNA double-strand breaks and apoptosis may relate to arsenite-induced damage and carcinogenesis, the mechanism of action remains obscure. Here, we find that, in human embryo lung fibroblast (HELF) cells, arsenite induces the activation of dependent protein kinase catalytic subunit (DNA-PKcs), which then phosphorylates and activates c-Jun N-terminal kinases 2 (JNK2), but not JNK1. As a positive regulator of p53, JNK2 binds to p53 and prevents p53 from murine double minute 2 (mdm2)-mediated, ubiquitin-proteasome-dependent degradation. Knockdown of DNA-PKcs/JNK2 signal pathway or p53 reduces apoptosis but elevates the DNA damage induced by a high level of arsenite. These results suggest that DNA-PKcs-mediated stabilization of p53 by JNK2 is involved in arsenite-induced DNA damage and apoptosis., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Objectives: To study the roles of heat shock proteins10 (HSP10) in the regulation of mouse ovarian granulose cell (GC) apoptosis, and to further define the possible roles of HSP10 in the development of polycystic ovary syndrome (PCOS)., Methods: Mouse HSP10 small interfering RNA (siRNA) and recombinant adenoviruses overexpressing HSP10 were constructed and subsequently transfected into cultured mouse ovarian GCs. After an infection period of 48 h, the expression levels of the HSP10 gene in mouse GCs were confirmed by Western blot. The GCs were also assessed for apoptosis using flow cytometry and the TUNEL assay. Apoptosis of GCs overexpressing HSP10 was assessed by flow cytometry after cisplatin treatment., Results: Compared with control group, the expression of HSP10 was decreased in mouse GCs infected with AdCMV-siRNA/HSP10, whereas mouse GCs infected with AdCMV-HSP10 showed increased HSP10 expression p < 0.05. Knock-down of HSP10 in mouse GCs significantly increased apoptosis (p < 0.05), whereas overexpression of HSP10 significantly suppressed apoptosis induced by cisplatin (p < 0.05)., Conclusion: In the present primary study, we have successfully employed recombinant adenovirus technologies to modulate HSP10 gene expression in mouse GCs, and examined the effects on apoptosis. Our experiments have demonstrated that knock-down of HSP10 induces apoptosis of mouse ovarian GCs, whereas overexpression of HSP10 suppresses apoptosis. These findings suggested that HSP10 may play a role in the regulation of apoptosis of mouse ovarian GCs.

Background: The FAS/FASLG system has been proposed to play a key role in germ cell apoptosis. To elucidate the role of the genetic variants of cell death pathway genes in male infertility, we genotyped the polymorphisms of FAS, FASLG and caspase-8 (CASP8) genes and evaluated their effects on sperm apoptosis and semen quality in infertile men., Methods: The genotypes of FAS, FASLG and CASP8 were determined in 620 infertile men. Sperm apoptosis rates were measured by terminal deoxynucleotidyl transferase (Tdt)-mediated dUTP nick end labelling (TUNEL) assay, and the semen quality analysis was performed using computer assisted sperm analysis., Results: We found that polymorphisms of FAS-670A/G (rs1800682: A>G) and CASP8-652 6N ins/del (rs3834129: -/CTTACT) were associated with sperm apoptosis and semen quality. Individuals with FAS-670GG showed low apoptosis rate and decreased sperm concentration, compared with the FAS-670AA genotype. Similarly, in comparison with the CASP8-652 6N ins/ins genotype, the CASP8-652 6N (ins/del+del/del) genotypes also showed significantly decreased sperm apoptosis rate and poor sperm motility. Other polymorphisms investigated did not appear to affect sperm apoptosis and semen quality., Conclusions: This study showed for the first time that functional variants of FAS and CASP8 might contribute to the dysfunctional apoptotic mechanism in germ cells, which could result in poor semen quality of ejaculated sperm.

In this study, the effects of 4-tert-octylphenol (OP) were examined on the viability of rat cultured Sertoli cells using the MTT assay and OP-induced apoptosis was detected by transmission electron microscope (TEM), flow cytometric analysis and Hoechst staining. In addition, RT-PCR was used to analyze the levels of Bcl-2 and Bax mRNA. Bcl-2, Bax and caspase-3 protein expressions were determined by Western blot analysis. Sertoli cells were treated with OP from 30 to 60microM for 6-24h. Decreased viability of Sertoli cells and increased apoptosis occurred in a concentration- and a time-dependent manner. The expression of Bcl-2 was down-regulated, while the expression of Bax up-regulated. OP also down-regulated the expression of 32kDa procaspase-3, which was cleaved to generate active subunit (17kDa). These results suggest that OP may induce Sertoli cell apoptosis by regulation of Bcl-2/Bax and caspase-3 activation.

Clinical trials have explored the use of natural and synthetic retinoids for the prevention of bladder cancer recurrence. Natural retinoids have been shown to inhibit bladder cancer growth. Here, we compared the effects of natural and synthetic retinoids in bladder cancer cells. Bladder cancer cell lines were treated with all-trans-retinoid acid (ATRA), N-4-hydroxyphenyl-retinamide (4-HPR) and 6-[3-(1-adamantyl)-4 hydroxyphenyl]-2-naphthalene carboxylic acid (CD437). Their effects on cell growth, apoptosis, cell cycle, gene expression, and retinoid acid receptors (RARs) and the JWA-retinoid response gene were assessed. Most of the bladder cancer cells were resistant to ATRA (1 and 10 microM). 4-HPR inhibited cell growth by 90% at 10 microM; however, CD437 showed the same effect at 1 microM. 4-HPR and CD437 increased G1 and decreased S phase. The three retinoids differentially affected p53, RARs, and JWA. Only CD437 increased Caspase 3 expression. The results demonstrated that 4-HPR and CD437 were more potent growth inhibitors and apoptosis inducers than ATRA. However, 4-HPR was effective at a concentration at least 10 microM. The in vitro results suggested the higher dose of 4-HPR in chemoprevention trial be considered.

The objective of this study was to evaluate the intravesical application of N-(4-hydroxyphenyl) retinamide (4-HPR) and adriamycin (ADM), as a treatment modality in a an animal model of chemically-induced bladder cancer. Bladder cancer developed in 50.0% of female Wistar rats, 4-6 weeks after intravesical application of the chemical carcinogen, N-methyl-N-nitrosourea (MNU). There was no significant difference in side effects induced by local versus systemic 4-HPR. Although tumor growth was inhibited by 4-HPR and ADM alone, tumor size was lower when both agents were used together. Apoptosis occurred at a higher rate in the combination group than when 4-HPR or ADM was used alone. The results suggest that intravesical use of 4-HPR and ADM may increase their efficacy in treatment of bladder cancer.

Arsenic trioxide (As2O3) has recently been used to treat acute promyelocytic leukaemia and has activity in vitro against several solid tumour cell lines where the induction of differentiation and apoptosis are the prime effects. The mechanism of As2O3-induced cell death has yet to be clarified, especially in solid cancers. In the present study, the human breast cancer cell line MCF-7 was examined as a cellular model for As2O3 treatment. The involvement of extracellular signal-regulated kinase (ERK), p38 and c-Jun N-terminal kinase (JNK) was investigated in As2O3-induced cell death. 3. It was found that As2O3 activates the prosurvival mitogen-activated protein kinase kinase (MEK)/ERK pathway in MCF-7 cells, which, conversely, may compromise the efficacy of As2O3. Hence, a combination treatment of As2O3 and MEK inhibitors was investigated to determine whether this treatment could lead to enhanced growth inhibition and apoptosis in MCF-7 cells. 4. Inhibition of MEK/ERK with the pharmacological inhibitors U0126 (10 micromol/L) or PD98059 (20 micromol/L) together with As2O3 (2 and 5 micromol/L) resulted in a significant enhancement of growth inhibition in breast cancer MCF-7 cells as determined by the 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide assay and [Methyl-3H]-thymidine incorporation. Furthermore, the results demonstrated that combined treatment with As2O3 and the MEK1/2 inhibitor U0126 could augment breast cancer MCF-7 cell apoptosis approximately twofold compared with the effects of the two drugs alone, as determined by Hoechst 33258 or annexin V/propidium iodide (PI) staining and flow cytometry. 5. In addition, As2O3 activated p38 in a dose-dependent manner, but had no effect on JNK1/2. Treatment with a p38 inhibitor did not prevent As2O3-induced apoptosis. 6. In conclusion, the results of the present study showed that enhanced apoptosis is detected in breast cancer MCF-7 cells in the presence of As2O3 and an MEK inhibitor, which may be a new promising adjuvant to current breast cancer treatments.

Triclosan (TCS) poses potential risks to reproduction and development due to its endocrine-disrupting properties. However, the mechanism of TCS's effects on early embryonic development is little known. Embryonic stem cells (ESC) and zebrafish embryos provide valuable models for testing the toxic effects of environmental chemicals on early embryogenesis. In this study, mouse embryonic stem cells (mESC) were acutely exposed to TCS for 24 h, and general cytotoxicity and the effect of TCS on pluripotency were then evaluated. In addition, zebrafish embryos were exposed to TCS from 2- to 24-h post-fertilization (hpf), and their morphology was evaluated. In mESC, alkaline phosphatase staining was significantly decreased after treatment with the highest concentration of TCS (50 μM). Although the expression levels of Sox2 mRNA were not changed, the mRNA levels of Oct4 and Nanog in TCS-treated groups were significantly decreased compared to controls. In addition, the protein levels of Oct4, Sox2 and Nanog were significantly reduced in response to TCS treatment. MicroRNA (miR)-134, an expression inhibitor of pluripotency markers, was significantly increased in TCS-treated mESC. In zebrafish experiments, after 24 hpf of treatment, the controls had developed to the late stage of somitogenesis, while embryos exposed to 300 μg/L of TCS were still at the early stage of somitogenesis, and three genes (Oct4, Sox2 and Nanog) were upregulated in treated groups when compared with the controls. The two models demonstrated that TCS may affect early embryonic development by disturbing the expression of the pluripotency markers (Oct4, Sox2 and Nanog).

Perfluorooctane sulfonate (PFOS) poses potential risks to reproduction and development. Mouse embryonic stem cells (mESCs) are ideal models for developmental toxicity testing of environmental contaminants in vitro. However, the mechanism by which PFOS affects early embryonic development is still unclear. In this study, mESCs were exposed to PFOS for 24 h, and then general cytotoxicity and pluripotency were evaluated. MTT assay showed that neither PFOS (0.2 µM, 2 µM, 20 µM, and 200 µM) nor control medium (0.1% DMSO) treatments affected cell viability. Furthermore, there were no significant differences in cell cycle and apoptosis between the PFOS treatment and control groups. However, we found that the mRNA and protein levels of pluripotency markers (Sox2, Nanog) in mESCs were significantly decreased following exposure to PFOS for 24 h, while there were no significant changes in the mRNA and protein levels of Oct4. Accordingly, the expression levels of miR-145 and miR-490-3p, which can regulate Sox2 and Nanog expressions were significantly increased. Chrm2, the host gene of miR-490-3p, was positively associated with miR-490-3p expression after PFOS exposure. Dual luciferase reporter assay suggests that miR-490-3p directly targets Nanog. These results suggest that PFOS can disturb the expression of pluripotency factors in mESCs, while miR-145 and miR-490-3p play key roles in modulating this effect.

Chemoresistance is the leading cause of breast cancer therapy failure, and studies of the mechanisms underlying chemoresistance and the treatment of drug-resistant tumors remain challenging. In the present study, we discovered a novel microRNA, miR3609, that influences the malignancy of breast cancer. Our results showed miR-3609 expression was lower in resistant breast cancer cells than in sensitive breast cancer cells (MCF-7), while PD-L1 expression was higher in resistant breast cancer cells than in sensitive breast cancer cells. Co-transfection of a miR-3609 plasmid with a luciferase construct containing the PD-L1 3′-untranslated region suppressed luciferase activity. Transfection of a miR-3609 mimic markedly suppressed PD-L1 protein expression in MDA-MB-231 and MDA-MB-468 cells in a dose-dependent manner and increased the sensitivity of MCF7/ADR cells to adriamycin, whereas transfection of a miR-3609 inhibitor enhanced PD-L1 protein expression in HBL-100 and MCF-7 cells. In addition, knockdown of PD-L1 by siRNA restored the sensitivity of MCF7/ADR cells to adriamycin. Mice injected with breast cancer cells stably overexpressing miR3609 survived markedly longer and had fewer tumors than mice injected with control miRNA (miR-sc)-transfected cells. Treatment with a CD8+ blocking antibody (anti-CD8) eliminated these effects, suggesting that CD8+ T cells are required for the efficacy of miR3609 in breast cancer. Further, low miR-3609 expression and high PD-L1 expression were correlated with poor prognosis in breast cancer patients. Therefore, restoration of miR-3609 expression may sensitize breast cancer to adriamycin by blocking PD-L1 expression. • miR-3609 is inversely correlated with PD-L1 level in human breast cancer tissue. • Restoration of miR-3609 expression sensitized breast cancer cell to adriamycin. • Knockdown of PD-L1 could restore breast cancer cell to adriamycin. [ABSTRACT FROM AUTHOR]

Cytochrome P450 2A13 (CYP2A13) is an extrahepatic enzyme that mainly expresses in human respiratory system, and it is reported to mediate the metabolic activation of aflatoxin B1. Due to the structural similarity, AFG1 is predicted to be metabolized by CYP2A13. However, the role of CYP2A13 in metabolic activation of AFG1 is unclear. In present study, human bronchial epithelial cells that stably express CYP2A13 (B-2A13) were used to conduct the effects of AFG1 on cytotoxicity, apoptosis, DNA damages, and their response protein expression. Low concentrations of AFG1 induced significant cytotoxicity and apoptosis, which was consistent with the increased expressions of pro-apoptotic proteins, such as C-PARP and C-caspase-3. In addition, AFG1 increased 8-OHdG and γH2AX in the nuclies and induced S phase arrest and DNA damage in B-2A13 cells, and the proteins related to DNA damage responses, such as ATM, ATR, Chk2, p53, BRCA1, and γH2AX, were activated. All the above effects were inhibited by nicotine (a substrate of CYP2A13) or 8-MOP (an inhibitor of CYP enzymes), confirming that CYP2A13 mediated the AFG1-induced cytotoxicity and DNA damages. Collectively, our findings first demonstrate that CYP2A13 might be an efficient enzyme in metabolic activation of AFG1 and helps provide a new insight into adverse effects of AFG1 in human respiratory system. [ABSTRACT FROM AUTHOR]

Background: 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) is the dominant PBDE congener in humans, wildlife, and the environment. It has been reported to be metabolized by cytochrome P450 (CYP) enzymes. Still, the effects of BDE47 on spermatogenesis failure are attracting an increasing amount of attention. However, it is unclear whether CYP-mediated metabolism contributes to BDE47-induced reproductive toxicity. Methodology and Principal Findings: The role of cytochrome P450 3A1 (CYP3A1) in the formation of oxidative metabolites of BDE47 and its induced spermatogenesis failure was investigated in SD rats. BDE47 significantly increased the expression and activity of CYP3A1 in rat liver, and 3-OH-BDE47, the major oxidative metabolite of BDE47, dose-dependently increased in rat liver, serum, and testis, which was aggravated by dexamethasone (DEX), an inducer of CYP3A1. Additionally, testicular 3-OH-BDE47 and reactive oxygen species (ROS) in seminiferous tubules increased especially when BDE47 was administered in combination with DEX, which was confirmed in GC-1 and GC-2 cells that 3-OH-BDE47 induced more ROS production and cell apoptosis via the upregulation of FAS/FASL, p-p53 and caspase 3. As a result, daily sperm production dose-dependently decreased, consistent with histological observations in giant cells and vacuolar spaces and increase in TUNEL-positive apoptotic germ cells. Conclusion: CYP3A1-mediated metabolic activation of BDE47 and the active metabolite 3-OH-BDE47 and consequent ROS played an important role in reduction of spermatogenesis by germ cell apoptosis. Our study helps provide new insights into the mechanism of reproductive toxicity of environmental chemicals. [ABSTRACT FROM AUTHOR]

Abstract: Caspase-8 (CASP8) plays a key role in apoptosis. We examined by genotyping whether the −652 six-nucleotide insertion-deletion (6N ins/del) polymorphism in the CASP8 promoter region was associated with prostate cancer risk in a hospital-based case-control study of 406 Chinese prostate cancer patients and 408 age-matched cancerfree controls. Additionally, 23 prostate cancer tissues were analyzed for CASP8 mRNA expression. We found a significantly decreased prostate cancer risk for the 6N ins/del genotype [adjusted odds ratio (OR)=0.68; 95% confidence interval (CI)=0.51-0.92] and del/del genotype (OR=0.34; 95%CI=0.19-0.63) compared with the ins/ins genotype. The 6N del allele was associated dose-dependently with decreased prostate cancer risk (P trend = 0.001). RT-PCR showed that individuals with the 6N del allele had lower CASP8 mRNA levels than those with the ins/ins genotype (P = 0.024). These findings suggested that the CASP8-652 6N ins/del polymorphism may affect the susceptibility to prostate cancer and reduce prostate cancer risk among Chinese men. [Copyright &y& Elsevier]

Humans are exposed to disinfection by-products (DBPs) mainly through drinking water ingestion and dermal contact. As an emerging class of nitrogenous DBPs (N-DBPs), haloacetamides (HAcAms) have been found to have significantly higher cytotoxicity than regulated DBPs. In this study, we investigated the cytotoxicity of HAcAms on two exposure pathway-related cell lines: human gastric epithelial GES-1 cells and immortalized keratinocytes HaCaT. Our results showed that the ranking order of cytotoxicity of 13 HAcAms was different between HaCaT and GES-1 cells. In addition, the 50% inhibitive concentration in HaCaT was 1.01–3.29 times that in GES-1. Further comparison among GES-1, HaCaT and CHO cell lines confirmed that different cell lines exhibited different sensitivity to the same compound. Importantly, HAcAms showed 5.83–7.13 × 104 times higher toxicity than the well-clarified DBP chloroform, clearly demonstrating the increased toxicity of HAcAms. Finally, using a novel high-content screening (HCS) analysis, we found that 39.29% of chlorinated HAcAms, 42.86% of brominated HAcAms and 16.07% of iodinated HAcAms significantly affected at least one of the cell-health parameters, such as nuclear size, membrane permeability, mitochondrial membrane potential, or cytochrome c release, in GES-1 or HaCaT cells. Thus, brominated HAcAms appear to have stronger effects under the sublethal exposure dose, possibly causing cytotoxicity via apoptosis. Together, our study provides new insights to the toxicity of HAcAms and a comprehensive toxicology dataset for health risk assessment. Unlabelled Image • Haloacetamides (HAcAms) showed higher cytotoxicity to GES-1 cells than HaCaT cells • Different cell lines exhibited different sensitivity to the same compound of HAcAms • HAcAms showed thousands times higher toxicity than the well-clarified DBP chloroform • Sublethal dosed Brominated HAcAms have stronger effects on cell health • HAcAms possibly cause cytotoxicity via apoptosis. [ABSTRACT FROM AUTHOR]

Our objective was to explore molecular markers and mechanism of BDE47 on spermatogenesis in mammals. Adult male SD rats were gavaged daily with corn oil containing 0, 0.001, 0.03, 1 or 20 mg BDE47/kg bw for eight weeks. Testes morphology was analyzed using electron microscopy, TUNEL, immunohistochemistry and morphometry. Differential proteome profile and western blotting were applied to determine molecular markers and protein expression. GC1-spg cells (mouse spermatogonial cells) were used to verify mechanism of BDE47. Data showed BDE47 reduced tubular epithelial thickness, impaired mitochondrial function and induced apoptosis in early leptotene spermatocytes. Proteomic study identified 70 differential spots corresponding to 64 proteins. 20 proteins related to apoptosis, 15 located in mitochondria. Exposure of GC1-spg cells showed BDE47 induced apoptosis, impaired mitochondria and decreased Bcl-2 in cells. Data indicate that BDE47 disrupts spermatogenesis, impairs mitochondrial function and induces apoptosis of early leptotene spermatocytes in rats probably via mitochondrial pathway. [ABSTRACT FROM AUTHOR]

Abstract: The activation of homeobox A10 (HOXA10) has been proved to be an important event in epithelial ovarian carcinogenesis, yet its regulation in epithelial ovarian cancer (EOC) is still not fully understood. Here, we aimed to reveal the mechanism that a predicted target miRNA regulates HOXA10 expression and the association of its expression with progression of EOC. Here, by using computer-assisted algorithms from PicTar, TargetScan, and miRBase, we identified that the predicted target miRNA of HOXA10 was miR-135a. MiR-135a expression in EOC tissues and controls was measured with quantitative RT-PCR. The role of miR-135a and HOXA10 in the growth and survival of several EOC cell lines was determined with several in vitro approaches. We found that miR-135a expression was downregulated in an EOC patient cohort. Also, patients with low miR-135a expression had shorter overall survival and progression-free survival durations than those with high expression. Functional analysis of three EOC-derived cell lines (SKOV-3, HEY, and OVCAR-3) demonstrated that miR-135a directly regulated HOXA10 expression by targeting its 3′-UTR. Inhibition of HOXA10 expression with miR-135a mimics and HOXA10 siRNA consistently resulted in cell apoptosis with concomitant enhancement of caspase-3, increase of p53 expression and reduction of Bcl-2 expression, and also suppressed cell growth and adhesion. These findings suggest that ubiquitous loss of miR-135a expression is a critical mechanism for the overexpression of HOXA10 in EOC cells, which is implicated in epithelial ovarian carcinogenesis. Furthermore, miR-135a may be predictive of EOC prognosis. [Copyright &y& Elsevier]

Abstract: Cypermethrin, a type II pyrethroid insecticide, is widely used throughout the world in agriculture, forestry, horticulture and homes. Though the neurotoxicity of cypermethrin has been thoroughly studied in adult rodents, little is so far available regarding the developmental toxicity of cypermethrin to fish in early life stages. To explore the potential developmental toxicity of cypermethrin, 4-h post-fertilization (hpf) zebrafish embryos were exposed to various concentrations of cypermethrin (0, 25, 50, 100, 200 and 400μgL−1) until 96h. Among a suite of morphological abnormalities, the unique phenotype curvature was observed at concentrations as low as 25μgL−1. Studies revealed that 400μgL−1 cypermethrin significantly increased malondialdehyde production. In addition, activity of antioxidative enzymes including superoxide dismutase and catalase were significantly induced in zebrafish larvae in a concentration-dependent manner. To further investigate the toxic effects of cypermethrin on fish, acridine orange (AO) staining was performed at 400μgL−1 cypermethrin and the result showed notable signs of apoptosis mainly in the nervous system. Cypermethrin also down-regulated ogg1 and increased p53 gene expression as well as the caspase-3 activity. Our results demonstrate that cypermethrin was able to induce oxidative stress and produce apoptosis through the involvement of caspases in zebrafish embryos. In this study, we investigated the developmental toxicity of cypermethrin using zebrafish embryos, which could be helpful in fully understanding the potential mechanisms of cypermethrin exposure during embryogenesis and also suggested that zebrafish could serve as an ideal model for studying developmental toxicity of environmental contaminants. [Copyright &y& Elsevier]

Abstract: Compared with increasing evidence suggesting that fenvalerate is neurotoxic to adults, further information regarding developmental toxicity of this compound attracts more attention. In this study, we used zebrafish as an environmental monitoring model to further explore the potential toxicity of fenvalerate. Our results demonstrated that larvae exposed to fenvalerate for 24–96h displayed obvious morphological abnormalities, and the LC50 concentrations were 131.95μg/L (LC50-24h), 107.18μg/L (LC50-48h), 21.76μg/L (LC50-72h), and 6.25μg/L (LC50-96h). To further investigate the effects of fenvalerate on embryos and larvae, acridine orange staining was performed at a 50μg/L concentration. Staining showed notable signs of apoptosis mainly in the brain. Further studies revealed that fenvalerate induced alterations in SOD activity in larvae were concentration dependent and also related to the length of exposure. Fenvalerate also down-regulated the expression of ogg1 and dlx2 genes in a concentration dependent manner, which indicated that the oxidative-DNA repair system as well as neurogenesis were impaired. In this study, we investigated the toxicity of fenvalerate using zebrafish, that provided new evidence of observable brain impairment during embryogenesis due to fenvalerate exposure and discussed their implications for the development of fenvalerate induced neurotoxicity. [Copyright &y& Elsevier]

Abstract: Genistein, an isoflavonoid present in soybeans, exhibits anti-carcinogenic effects. Several studies have shown that genistein inhibits cell proliferation and triggers apoptosis in human breast cancer cells. In this study, we assessed the role of the MEK-ERK cascade in the regulation of genistein-mediated cell apoptosis in MDA-MB-231 cells. The results indicate that genistein, in a concentration-dependent manner, suppresses the protein levels of MEK5, total ERK5, and phospho-ERK5, effects that are consistent with inhibition of cell growth and induction of apoptosis. Exposure of these cells to genistein results in a concentration-dependent decrease in NF-κB/p65 protein levels and DNA-binding activity of NF-κB. Genistein down-regulates Bcl-2 and up-regulates Bax. NF-κB binding sites are present in the promoter of Bcl-2, suggesting that genistein might inhibit the expression of Bcl-2 through down-regulation of NF-κB. Exposure of MDA-MB-231 cells to genistein results in cleavage of caspase-3 and induction of caspase-3 activity in a concentration-dependent manner. Genistein inhibits NF-κB activity via the MEK5/ERK5 pathway; it also inhibits cell growth and induces apoptosis. In conclusion, inhibition of the MEK5/ERK5/NF-κB pathway may be an important mechanism by which genistein suppresses cell growth and induces apoptosis. [Copyright &y& Elsevier]

Reagent potassium bisperoxo (1,10-phenanthroline) oxovanadate [bpV(phen)] was evaluated as a new apoptotic drug by employing a ratiometric two-photon fluorescent pH probe Lyso-PCE , and the real-time visualization of bpV(phen)-induced apoptosis was realized under two-photon excitation. • A ratiometric pH fluorescent probe was designed with a dual-function group. • Probe has the ability of quantitative testing pH in both solution and living cells. • Probe can be used to real time monitor drug-induced apoptosis in living cells. • Probe works as a new and promising tool for evaluating apoptosis-related drugs. The level of apoptosis is directly related to the occurrence of cancer and other diseases. Real-time continuous monitoring of apoptotic process of living cells has great potential for early diagnosis of related diseases, as well as evaluation of therapeutic effect and screening of apoptotic drugs. This work proposed a ratiometric two-photon fluorescent probe Lyso-PCE equipped with a dual-function pyridine, as a pH-sensitive and specific lysosome-targeted group. A clear linearity relationship between two-channel fluorescence intensity ratios of Lyso-PCE and pH values was established in both solutions and living cells. Thanks to its ability of quantitative detection of pH, probe Lyso-PCE can detect the dynamic pH changes of lysosomes treated by chloroquine, and also can be used to in situ monitor dexamethasone-induced apoptosis. More importantly, reagent potassium bisperoxo (1,10-phenanthroline) oxovanadate (bpV(phen)) was evaluated and testified as a new apoptotic drug by Lyso-PCE , and the real-time visualization of bpV(phen)-induced apoptosis was realized under two-photon excitation. Our results provide a new and promising strategy for evaluating and screening apoptosis-related drugs. [ABSTRACT FROM AUTHOR]