Microwave ablation combined with PD-L1 blockade synergistically promotes Cxcl9-mediated antitumor immunity.

Although microwave ablation (MWA) is an important curative therapy in colorectal cancer liver metastasis, recurrence still occurs clinically. Our previous studies have shown that the expression of programmed cell death 1 ligand 1 (PD-L1) is upregulated following MWA, suggesting that MWA combined with anti-PD-L1 treatment can serve as a promising clinical therapeutic strategy against cancer. Using MWA-treated preclinical mice models, MWA combined with αPD-L1 treatment decreased tumor growth and prolonged overall survival (OS). Furthermore, through flow cytometry and single-cell RNA sequencing analysis, we determined that the MWA plus αPD-L1 therapy significantly suppressed CD8+ T cell exhaustion and enhanced their effector function. A significant increase in γ-interferon (IFN-γ) stimulated transcription factors, specifically Irf8, was observed. This enhancement facilitated the polarization of tumor-associated macrophages (TAM1s and TAM2s) through the nuclear factor-κB/JAK-STAT1 signaling pathway. Furthermore, the combination therapy stimulated the production of CXC motif chemokine ligand (CXCL9) by TAM1s and tumor cells, potentially increasing the chemotaxis of CD8 T cells and Th1 cells. Knocking out Cxcl9 in MC38 tumor cells or using CXCL9 blockade enhanced tumor growth of untreated tumors and shortened OS. Taken together, our study showed that blocking the IFN-γ-Cxcl9-CD8+ T axis promoted tumor progression and discovered a potential involvement of IRF8-regulated TAMs in preventing T cell exhaustion. Collectively, we identified that the combination of MWA with anti-PD-L1 treatment holds promise as a therapeutic strategy to rejuvenate the immune response against tumors. This merits further exploration in clinical studies.

Impact of Extended and Combined Exposure of Bisphenol Compounds on Their Chromosome-Damaging Effect─Increased Potency and Shifted Mode of Action.

Bisphenol (BP) compounds are important environmental pollutants and endocrine disruptors. BPs are capable of inducing DNA/chromosome breaks (clastogenesis, involved in carcinogenesis), which requires activation by human CYP1A1. We hypothesized that combined BPs and extended (from the standard two-cell cycle) exposure may enhance their genotoxicity via modulating CYP enzymes. In this study, individual and combined BPA/BPF/BPS/BPAF and a human hepatoma (HepG2) cell line were used for testing several genotoxicity end points. Exposing for a two-cell cycle period (48 h), each BP alone (0.625-10 µM) was negative in the micronucleus test, while micronucleus was formed under three- (72 h) and four-cell cycle (96 h) exposure; BP combinations further elevated the potency (with nanomolar thresholds). Immunofluorescence analysis of the centromere with formed micronucleus indicated that 48 h exposure produced centromere-negative micronucleus and phosphorylated histone H2AX (γ-H2AX) (evidencing clastogenesis), while extended (72 and 96 h) exposure formed centromere-positive micronucleus and phosphorylated histone H3 (p-H3) (indicating chromosome loss, i.e., aneugenesis); moreover, 1-aminotriabenzotriazole (CYP inhibitor) selectively blocked the formation of centromere-negative micronucleus and γ-H2AX, without affecting that of centromere-positive micronucleus and p-H3. This study suggests that the genotoxicity of BPs is potentiated by combined and extended exposure, the latter being specific for aneuploidy formation, a CYP activity-independent effect.

Induction of clastogenesis and gene mutations by carbamazepine (at its therapeutically effective serum levels) in mammalian cells and the dependence on human CYP2B6 enzyme activity.

Carbamazepine (CBZ, an antiepileptic) is metabolized by multiple CYP enzymes to its epoxide and hydroxides; however, whether it is genotoxic remains unclear. In this study, molecular docking (CBZ to CYPs) and cytogenotoxic toxicity assays were employed to investigate the activation of CBZ for mutagenic effects, in various mammalian cell models. Docking results indicated that CBZ was valid as a substrate of human CYP2B6 and 2E1, while not for CYP1A1, 1A2, 1B1 or 3A4. In the Chinese hamster (V79) cell line and its derivatives genetically engineered for the expression of human CYP1A1, 1A2, 1B1, 2E1 or 3A4 CBZ (2.5 ~ 40 µM) did not induce micronucleus, while in human CYP2B6-expressing cells CBZ significantly induced micronucleus formation. In a human hepatoma C3A cell line, which endogenously expressed CYP2B6 twofold higher than in HepG2 cells, CBZ induced micronucleus potently, which was blocked by 1-aminobenzotriazole (inhibitor of CYPs) and ticlopidine (specific CYP2B6 inhibitor). In HepG2 cells CBZ did not induce micronucleus; however, pretreatment of the cells with CICTO (CYP2B6 inducer) led to micronucleus formation by CBZ, while rifampicin (CYP3A4 inducer) or PCB126 (CYP1A inducer) did not change the negative results. Immunofluorescent assay showed that CBZ selectively induced centromere-free micronucleus. Moreover, CBZ induced double-strand DNA breaks (γ-H2AX elevation, by Western blot) and PIG-A gene mutations (by flowcytometry) in C3A (threshold being 5 µM, lower than its therapeutic serum concentrations, 17 ~ 51 µM), with no effects in HepG2 cells. Clearly, CBZ may induce clastogenesis and gene mutations at its therapeutic concentrations, human CYP2B6 being a major activating enzyme.

Long term exposure of saxitoxin induced cognitive deficits and YAP1 cytoplasmic retention.

While most studies assessed the acute toxicity of saxitoxin (STX), fewer studies focus on the long-term degenerative effects of STX on the central nervous system. We investigated the cognitive impairment and hippocampal damages of 6 months' exposure of low-dose STX to C57BL/6NJ mice with behavioral tests, H&E staining, and Western blots, and the possible mechanism (Ppp1C, YAP1, tau-phosphorylation) underlies the pathological changes. Furthermore, we discussed the specific localization of YAP1 in N2a cells induced by STX and the effect of inactivated Ppp1C on its downstream protein YAP1 in the Hippo signal pathway. We found STX intoxicated mice showed declined cognitive performance in both NOR test and MWM test, degenerations in the CA1 area of hippocampi. STX induced up-regulation expression of Ppp1C and YAP1 in hippocampus and N2a cells. Meanwhile, STX treatment induced cell apoptosis and Tau protein hyperphosphorylation. In addition, STX treatment promoted YAP1 cytoplasmic retention that indicates the activation of Hippo pathway, while depletion of Ppp1C inactivate YAP1 during the treatment of STX. Our results highlight the role of Ppp1C and YAP1 cytoplasmic retention in chronic low-dose STX intoxication.

Event-Triggered Bounded Consensus Tracking for Second-Order Nonlinear Multi-Agent Systems with Uncertainties.

This paper is concerned with event-triggered bounded consensus tracking for a class of second-order nonlinear multi-agent systems with uncertainties (MASs). Remarkably, the considered MASs allow multiple uncertainties, including unknown control coefficients, parameterized unknown nonlinearities, uncertain external disturbances, and the leader's control input being unknown. In this context, a new estimate-based adaptive control protocol with a triggering mechanism is proposed. We rule out Zeno behavior by testifying that the lower bound on the interval between two consecutive events is positive. It is shown that under the designed protocol, all signals caused by the closed-loop systems are bounded globally uniformly and tracking errors ultimately converge to a bounded set. The effectiveness of the devised control protocol is demonstrated through a simulation example.

Alleviation of doxorubicin-induced cardiomyocyte death through miR-147-y-mediated mitophagy.

Doxorubicin (DOX) is a commonly used antitumor drug. However, it may cause severe cardiotoxicity, apoptosis being a major change. A recent report indicates that miR-147 expression is decreased in the myocardium of a myocardial infarction model, suggesting a potential role of this miRNA in DOX-induced cardiomyocyte toxicity. In this study, freshly isolated neonatal pig cardiomyocytes were used; following transfection of a miR-147-y mimic, the cell death induced by DOX was alleviated, represented by augmented mitophagy [indicated by a decrease in P62, and increases in LC3, PINK1, parkin mRNA, LC3Ⅱ/Ⅰ, beclin-1, PINK1, and parkin including p-parkin (Ser65) protein expression], prohibited cell apoptosis as determined by TUNEL staining, and the suppression of caspase-3 transcription and cleaved caspase-3 translation. In cells transfected with an miR-147-y inhibitor, DOX-induced mitophagy was decreased, while apoptosis was increased. Additionally, RAPTOR gene silencing in cardiomyocytes exposed to DOX increased the rate of mitophagy and decreased that of apoptosis as compared with the treatment with DOX alone. Moreover, RAPTOR overexpression downregulated the rate of mitophagy and increased that of apoptosis in cells exposed to DOX. RAPTOR was confirmed as the target gene of miR-147-y based on the results of luciferase reporter gene assays and the opposite effects of the miR-147-y mimic and miR-147-y inhibitor on RAPTOR expression. In summary, our study suggests that miR-147-y mediates DOX-induced cardiomyocyte mitophagy while suppresses apoptosis by targeting RAPTOR, thus playing a protective role in DOX-induced cardiomyocyte damage.

Bisphenol F suppresses insulin-stimulated glucose metabolism in adipocytes by inhibiting IRS-1/PI3K/AKT pathway.

Obesity is one of the risk factors of metabolic diseases. Decreased sensitivity to insulin or impairment of the insulin signaling pathway may affect the metabolism of adipose tissue. Bisphenol F (BPF) has been widely used in various products as a substitute for bisphenol A (BPA). BPA has been defined as "obesogen". However, knowledge about the correlation between BPF and obesity is very limited. This study was aimed to explore the effects of BPF on glucose metabolism and insulin sensitivity in mammalian tissues, using a mouse 3T3-L1 adipocyte line as the model. Differentiated 3T3-L1 adipocytes were treated with BPF at various concentrations for 24 h or 48 h, followed by the measurement of cell viability, lipid accumulation, expression levels of adipocytokines, glucose consumption, and impairment of the insulin signaling pathway. The results indicated that BPF had no effect on the size of 3T3-L1 adipocytes, but the expression of leptin, adiponectin and apelin was decreased, while that of chemerin and resistin was increased after 48 h of BPF treatment. Moreover, BPF inhibited the glucose consumption, the expression of GLUT4, and its translocation to the plasma membranes in 3T3-L1 adipocytes. Western blot analysis indicated that the activation of IRS-1/PI3K/AKT signaling pathway was inhibited by BPF, which resulted in reduced GLUT4 translocation. In conclusion, our data suggest that exposure of adipocytes to BPF may alter the expression of calorie metabolism-related adipokines and suppress insulin-stimulated glucose metabolism by impairing the insulin signaling (IRS-1/PI3K/AKT) pathway.

Fixed-Time Leader-Following Consensus Tracking Control for Nonliear Multi-Agent Systems under Jointly Connected Graph.

This paper researches the fixed-time leader-following consensus problem for nonlinear multi-agent systems (MASs) affected by unknown disturbances under the jointly connected graph. In order to achieve control goal, this paper designs a fixed-time consensus protocol, which can offset the unknown disturbances and the nonlinear item under the jointly connected graph, simultaneously. In this paper, the states of multiple followers can converge to the state of the leader within a fixed time regardless of the initial conditions rather than just converging to a small neighborhood near the leader state. Finally, a simulation example is given to illustrate the theoretical result.

Influence of Bisphenol Compounds at Nanomolar Concentrations on Chromosome Damage Induced by Metabolically Activated Carcinogens in HepG2 Cells.

Bisphenol (BP) compounds are endocrine-disrupting organic pollutants. BPs may increase the messenger RNA (mRNA) transcripts of nuclear receptors (NRs) regulating the expression of xenobiotic-metabolizing cytochrome P450 (CYP) enzymes. Their impact on the genotoxicity of metabolically activated carcinogens, however, remains unknown. In this study, effects of the bisphenols A, F, S, and AF on the expression of the aryl hydrocarbon receptor (AhR), the pregnane X receptor (PXR), the constitutive androstane receptor, and individual xenobiotic-metabolizing CYP enzymes in a human hepatoma (HepG2) cell line were investigated, along with in silico binding studies of BPs to each receptor. The results indicated that each BP at 1 to 100 nM concentrations increased the mRNA transcripts and protein levels of AhR, PXR, CYP1A1, 1A2, 1B1, 2E1, and 3A4. The predicted affinities of the BPs for binding AhR were comparable to those of potent agonists. Pretreatment of HepG2 cells with each BP potentiated the induction of micronuclei by benzo[a]pyrene, aflatoxin B1, benzene, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; this effect was abolished/reduced by inhibitors of NRs and/or CYPs. Our study suggests that BPs at human exposure levels may aggravate chromosome damage by several impactful carcinogens in human cells by inducing relevant CYP enzymes, mostly via NR modulation.

Potent aneugenicity of 1-methylpyrene in human cells dependent on metabolic activation by endogenous enzymes.

1-Methylpyrene (1-MP) is a common environmental pollutant and animal carcinogen. After sequential activation by cytochromes P450 and sulfotransferases, it induced gene mutations and micronuclei in mammalian cells. The type of micronuclei formed, entire chromosomes or fragments, was not analysed. In this study, 1-MP and its primary metabolite, 1-hydroxymethylpyrene (1-HMP), were investigated for the induction of centromere-positive and -negative micronuclei in the human hepatoma cell line HepG2 and its derivative C3A, expressing relevant enzymes at higher levels. Under a short-exposure (9 h)/long-recovery regime (2 cell cycles in total), 1-MP and 1-HMP provided negative test results in HepG2 cells. However, they induced micronuclei in C3A cells, the effect being blocked by 1-aminobenzotriazole (inhibitor of cytochromes P450s) and reduced by pentachlorophenol (inhibitor of sulfotransferases). Immunofluorescence staining of centromere protein B in the micronuclei revealed purely clastogenic effects under this regime. Unexpectedly, 1-MP and 1-HMP at concentrations 1/5-1/4 of that required for micronuclei formation led to mitotic arrest and spindle aberrations, as detected by immunofluorescence staining of ß- and γ-tubulin. Following extended exposure (72 h, 2 cell cycles, no recovery), damage to the spindle apparatus and centrosomes was detected at even lower concentrations, with concurrent formation of micronuclei. At low concentrations (1-8 µM 1-MP, 0.25-0.5 µM 1-HMP), the micronuclei induced were unexceptionally centromere-positive. Thus, the chromosome-damaging mechanism of 1-MP was regime and concentration dependent: potently aneugenic under persistent exposure, while clastogenic at higher concentrations following a short-exposure/long-recovery regime. This is a convincing evidence for the existence of metabolic activation-dependent aneugens.

Potent Clastogenicity of Bisphenol Compounds in Mammalian Cells-Human CYP1A1 Being a Major Activating Enzyme.

Bisphenols (BPs) are environmental pollutants with relevant DNA damage in human population; however, they are generally inactive in standard mutagenicity assays, possibly due to insufficient metabolic activation. In this study, induction of micronuclei and double-strand DNA breaks by BPA, BPF, and BPS in Chinese hamster V79-derived cell lines expressing various human CYP enzymes and a human hepatoma (C3A) (metabolism-proficient) cell line were investigated. Molecular docking of BPs to human CYPs indicated some substrate-enzyme potentials, including CYP1A1 for each compound, which did not induce micronuclei in V79-derived cell lines expressing human CYP1A2, 2E1, or 3A4 but became positive in human CYP1A1-expressing (V79-hCYP1A1) cells. In V79-hCYP1A1 and C3A cells, all compounds induced double-strand DNA breaks and micronuclei formation, which were blocked/significantly attenuated by 1-aminobenzotriazole (CYP inhibitor) or 7-hydroxyflavone (selective CYP1A1 inhibitor). Coexposure of C3A cells to pentachlorophenol (sulfotransferase 1 inhibitor) or ketoconazole (UDP-glucuronosyltransferase 1A inhibitor) potentiated micronuclei induction by each compound, with thresholds lowered from 2.5-5.0 to 0.6-1.2 µM. Immunofluorescence staining of centromere protein B with micronuclei formed in C3A cells by each compound indicated pure clastogenic effects. In conclusion, BPs are potently clastogenic in mammalian cells, which require activation primarily by human CYP1A1 and are negatively modulated by phase II metabolism.

Impact of some social and clinical factors on the development of postpartum depression in Chinese women.

BACKGROUND: Postpartum depression (PPD) is prevalent and may present major adverse impacts on mother and child health. According to previous studies, mostly from the western society, PPD may have complicated etiologies, such as genetic, social and psychological factors. The aim of this study was to explore the associations of some social and clinical factors, particularly those unique in Chinese, with significant PPD symptoms. METHODS: A sample of 556 pregnant women in their 36th to 40th gestational week were randomly recruited in a cross-sectional study using a self-reported questionnaire, which collected maternal sociodemographic and clinical information. During their 2nd to 4th postpartum months, 522 participants responded to our screening of significant PPD symptoms, based on a score of Edinburgh Postnatal Depression Scale ≥9. RESULTS: A total of 90 (17.3%) participants were identified with significant PPD symptoms, and the following factors were observed more frequently in women with significant PPD symptoms (PPD+) than with fewer symptoms (PPD-): intensive involvement of parents-in-law in a participant's life (living together with her, taking care of her, or discriminating against a female baby), lack of support from husband, cesarean delivery, and breast milk insufficiency (supplemented with formula). After multiple logistic regression analysis, parents-in-law's preference to baby boy while devaluing baby girl, dissatisfaction with husband's support, cesarean delivery, and mixed feeding were strongly associated with significant PPD symptoms. CONCLUSION: The potential risk factors for significant PPD symptoms, i.e., "son preference" custom, cesarean delivery and mixed feeding, deserve confirmation in continued, especially clinical diagnosis-based longitudinal studies.

Trichloroethylene-induced downregulation of miR-199b-5p contributes to SET-mediated apoptosis in hepatocytes.

Trichloroethylene (TCE) is a ubiquitous toxicant widespread in our environment. Exposure to TCE can cause severe liver damage. In previous studies, we detected an abnormal elevation of SET (a protein encoded by the SETgene in humans) which was observed in human HL-7702 cells (L-02 hepatocytes) under the treatment of TCE. Moreover, further study indicated that SET acts as an important mediator in TCE-induced hepatocyte apoptosis. The major functions of SET have been elucidated, while the regulatory mechanism responsible for modulation of SET remains unclear. In this study, four major microRNA-related databases were used to screen and identify 6 candidate microRNAs involved in the regulation of SET. Subsequent verification indicated that miR-21 and miR-199b-5p were decreased in TCE-treated L-02 cells, suggesting that miR-21 and miR-199b-5p (miR199b for short) miR199b potentially regulate SET expression. Additionally, the dual-luciferase system revealed that only miR199b could directly bind to untranslated region (3'-UTR) of the SETgene. Modulation of SET by miR199b was verified through overexpression and knockdown of miR199b in L-02 cells. Assessment of apoptosis indicated that elevated miR199b attenuated TCE-induced apoptosis, while reduced miR199b enhanced it. In summary, this study suggests that in cultured hepatocytes, TCE-induced suppression of miR199b drives SET induction, which further mediates the response to TCE.

Potent mutagenicity of some non-planar tri- and tetrachlorinated biphenyls in mammalian cells, human CYP2E1 being a major activating enzyme.

Polychlorinated biphenyls (PCBs) have been classified as human carcinogens. Mutagenicity of lower chlorinated biphenyls as well as activation of transcription factors by some other congeners may contribute to the carcinogenicity of PCBs. Recently, we reported that human CYP2E1 activates mono- and dichlorobiphenyls to mutagens. However, mutagenicity of other PCBs and the involvement of other CYPs remained unknown. In this study, Chinese hamster V79-derived cell lines genetically engineered for expression of individual human CYP enzymes and a human hepatocyte (L-02) line endogenously expressing various CYPs were used to determine the activities of several tri- and tetrachlorobiphenyls to induce micronuclei and gene mutations. 2,3,4'-Trichlorobiphenyl, 2,3,3'-trichlorobiphenyl, 2,4,4',5-tetrachlorobiphenyl and 2,2',5,5'-tetrachlorobiphenyl efficiently induced micronuclei and/or gene mutations in V79-derived cells at low micromolar concentrations, depending on human CYP2E1, while they were inactive in parental V79-Mz cells and weakly positive or inactive in V79-derived cells expressing human CYP1A1, 1A2, 1B1 or 3A4. The induction of gene mutations in human CYP2E1-expressing V79 cells by 2,3,4'-trichlorobiphenyl and 2,4,4',5-tetrachlorobiphenyl was more potent than that of N-nitrosodimethylamine, a strong carcinogen activated by CYP2E1. As representative PCB compounds, 2,3,3'-trichlorobiphenyl and 2,3,4'-trichlorobiphenyl induced micronuclei in L-02 cells, and this effect was blocked by specific CYP2E1 inhibition, wherein the effects of benzo[a]pyrene and aflatoxin B1 (activated by some CYPs other than CYP2E1) were unaffected. This study demonstrates that some non-planar tri- and tetrachlorobiphenyls are potent mutagens in mammalian cells-more potent than previously tested mono- and dichlorobiphenyls-and that among several human CYP enzymes, CYP2E1 is most efficient in activating these environmental contaminants.

Associations of dietary habits, physical activity and cognitive views with gestational diabetes mellitus among Chinese women.

OBJECTIVE: To evaluate the relationship between dietary habits, physical activity and cognitive views and the risk of gestational diabetes mellitus (GDM) in Chinese women. DESIGN: A cross-sectional study to explore the potential risk factors of GMD through the International Physical Activity Questionnaire, an FFQ and a self-designed structured questionnaire, respectively. SETTING: Guangzhou, Guangdong Province, China. SUBJECTS: Chinese pregnant women (n 571) who underwent a 75-g oral glucose tolerance test at their 24th to 28th gestational week. RESULTS: Thirteen per cent of the investigated women were identified as having GDM, and an increased intake of local featured foods and lower physical activity were observed in the GDM-positive group v. the GDM-negative group. Women who regarded early-pregnancy morning sickness as relevant to fetal abnormalities and those with unlimited dietary intake after the ending of morning sickness both had an increased risk for GDM (P = 0·018 and P = 0·038, respectively). After multiple logistic regression analysis, cognitive views for unlimited food intake subsequent to morning sickness, increased consumption of energy-dense snack foods and high-glycaemic-index fruits were strongly associated with the risk of GDM (OR = 1·911, P = 0·032; OR = 1·050, P = 0·001; and OR = 1·002, P = 0·017, respectively). CONCLUSIONS: Local featured foods and incorrect cognitive views on pregnancy-related health were closely related to the risk of GDM in Chinese women. Intensive health education about pregnancy physiology and reasonable dietary and physical exercise behaviours should be strengthened for the control of GDM.

Hydrogen peroxide induces adaptive response and differential gene expression in human embryo lung fibroblast cells.

Hydrogen peroxide (H2 O2 ), a substance involved in cellular oxidative stress, has been observed to induce an adaptive response, which is characterized by a protection against the toxic effect of H2 O2 at higher concentrations. However, the molecular mechanism for the adaptive response remains unclear. In particular, the existing reports on H2 O2 -induced adaptive response are limited to animal cells and human tumor cells, and relatively normal human cells have never been observed for an adaptive response to H2 O2 . In this study, a human embryo lung fibroblast (MRC-5) cell line was used to model an adaptive response to H2 O2 , and the relevant differential gene expressions by using fluoro mRNA differential display RT-PCR. The results showed significant suppression of cytotoxicity of H2 O2 (1100 µM, 1 h) after pretreatment of the cells with H2 O2 at lower concentrations (0.088-8.8 µM, 24 h), as indicated by cell survival, lactate dehydrogenase release, and the rate of apoptotic cells. Totally 60 mRNA components were differentially expressed compared to untreated cells, and five of them (sizing 400-600 bp) which demonstrated the greatest increase in expression were cloned and sequenced. They showed identity with known genes, such as BCL-2, eIF3S5, NDUFS4, and RPS10. Real time RT-PCR analysis of the five genes displayed a pattern of differential expression consistent with that by the last method. These five genes may be involved in the induction of adaptive response by H2 O2 in human cells, at least in this particular cell type.

Specific human CYP enzymes-dependent mutagenicity of tris(2-butoxyethyl) phosphate (an organophosphorus flame retardant) in human and hamster cell lines.

Tris(2-butoxyethyl) phosphate (TBOEP) is an organophosphorus flame retardant ubiquitously present in the environment and even the human body. TBOEP is toxic in multiple tissues, which forms dealkylated and hydroxylated metabolites under incubation with human hepatic microsomes; however, the impact of TBOEP metabolism on its toxicity, particularly mutagenicity (typically requiring metabolic activation), is left unidentified. In this study, the mutagenicity of TBOEP in human hepatoma cell lines (HepG2 and C3A) and the role of specific CYPs were studied. Through molecular docking, TBOEP bound to human CYP1A1, 1B1, 2B6 and 3A4 with energies and conformations favorable for catalyzing reactions, while the conformations of its binding with human CYP1A2 and 2E1 appeared unfavorable. In C3A cells (endogenous CYPs being substantial), TBOEP exposing for 72 h (2-cell cycle) at low micromolar levels induced micronucleus, which was abolished by 1-aminobenzotriazole (inhibitor of CYPs); in HepG2 cells (CYPs being insufficient) TBOEP did not induce micronucleus, whose effect was however potentiated by pretreating the cells with PCB126 (CYP1A1 inducer) or rifampicin (CYP3A4 inducer). TBOEP induced micronucleus in Chinese hamster V79-derived cell lines genetically engineered for stably expressing human CYP1A1 and 3A4, but not in cells expressing the other CYPs. In C3A cells, TBOEP selectively induced centromere protein B-free micronucleus (visualized by immunofluorescence) and PIG-A gene mutations, and elevated γ-H2AX rather than p-H3 (by Western blot) which indicated specific double-strand DNA breaks. Therefore, this study suggests that TBOEP may induce DNA/chromosome breaks and gene mutations in human cells, which requires metabolic activation by CYPs, primarily CYP1A1 and 3A4.

Metabolism-dependent mutagenicity of two structurally similar tobacco-specific nitrosamines (N-nitrosonornicotine and N-nitrosoanabasine) in human cells, partially different CYPs being activating enzymes.

N-nitrosonornicotine (NNN) and N-nitrosoanabasine (NAB) are both tobacco-specific nitrosamines bearing two heterocyclic amino groups, NAB bearing an extra -CH2- group (conferring a hexa- rather than penta-membered cycle) but with significantly decreased carcinogenicity. However, their activating enzymes and related mutagenicity remain unclear. In this study, the chemical-CYP interaction was analyzed by molecular docking, thus the binding energies and conformations of NNN for human CYP2A6, 2A13, 2B6, 2E1 and 3A4 appeared appropriate as a substrate, so did NAB for human CYP1B1, 2A6, 2A13 and 2E1. The micronucleus test in human hepatoma (HepG2) cells with each compound (62.5-1000 µM) exposing for 48 h (two-cell cycle) was negative, however, pretreatment with bisphenol AF (0.1-100 nM, CYPs inducer) and ethanol (0.2% v:v, CYP2E1 inducer) potentiated micronucleus formation by both compounds, while CITCO (1 µM, CYP2B6 inducer) selectively potentiated that by NNN. In C3A cells (endogenous CYPs enhanced over HepG2) both compounds induced micronucleus, which was abolished by 1-aminobenzotriazole (60 µM, CYPs inhibitor) while unaffected by 8-methoxypsoralen (1 µM, CYP2A inhibitor). Consistently, NNN and NAB induced micronucleus in V79-derived recombinant cell lines expressing human CYP2B6/2E1 and CYP1B1/2E1, respectively, while negative in those expressing other CYPs. By immunofluorescent assay both compounds selectively induced centromere-free micronucleus in C3A cells. In PIG-A assays in HepG2 cells NNN and NAB were weakly positive and simply negative, respectively; however, in C3A cells both compounds significantly induced gene mutations, NNN being slight more potent. Conclusively, both NNN and NAB are mutagenic and clastogenic, depending on metabolic activation by partially different CYP enzymes.

Human CYP1A1-activated aneugenicity of aflatoxin B1 in mammalian cells and its combined effect with benzo(a)pyrene.

Aflatoxin B1 (AFB1) is the most toxic mycotoxin and a proven human carcinogen that requires metabolic activation, known by cytochrome P450 (CYP) 1A2 and 3A4. Previous evidence showed that AFB1 is activated by human recombinant CYP1A1 expressed in budding yeast. Yet, the toxicity, in particular the genotoxicity of the reactive metabolites formed from AFB1 remains unclear. Humans could be exposed to both AFB1 and benzo(a)pyrene (BaP) simultaneously, thus we were interested in their combined genotoxic effects subsequent to metabolic activation by CYP1A1. In this study, molecular docking of AFB1 to human CYP1A1 indicated that AFB1 is valid as a substrate. In the incubations with AFB1 in human CYP1A1-expressed microsomes, AFM1 as a marking metabolite of AFB1 was detected. Moreover, AFB1 induced micronucleus formation in a Chinese hamster V79-derived cell line and in a human lung epithelial BEAS-2B cell line, both expressing recombinant human CYP1A1, V79-hCYP1A1 and 2B-hCYP1A1 cells, respectively. Immunofluorescence of centromere protein B stained micronuclei was dominant in AFB1-treated BEAS-2B cells exposed to AFB1, suggesting an aneugenic effect. Moreover, AFB1 elevated the levels of ROS, 8-OHdG, AFB1-DNA adduct, and DNA breaks in 2B-hCYP1A1 cells, compared with those in the parental BEAS-2B cells. Meanwhile, AFB1 increased CYP1A1, RAD51, and γ-H2AX protein levels in 2B-hCYP1A1 cells, which were attenuated by the CYP1A1 inhibitor bergamottin. Co-exposure of AFB1 with BaP increased 8-OHdG, RAD51, and γ-H2AX levels (indicating DNA damage). In conclusion, AFB1 could be activated by human CYP1A1 for potent aneugenicity, which may be further enhanced by co-exposure to BaP.

The expression and function of microRNA-203 in lung cancer.

We aimed to determine the expression of microRNA-203 (miR-203) in human lung cancer cell lines and to evaluate the effects of miR-203 by targeting survivin, on the lung cancer cell line 95-D to provide potential new strategies for treating lung cancer. The expression of miR-203 was detected using quantitative real-time PCR (qRT-PCR) in the in vitro cultured lung cancer cells A549, HCC827, NCI-H1299, and 95-D as well as in normal human bronchial epithelial cells. Following a 72-h transfection with the miR-203 precursor in 95-D lung cancer cells, the change in miR-203 expression was detected using qRT-PCR and the resulting effect on survivin protein expression was ascertained by Western blot analysis. The influence of miR-203 on the viability of 95-D lung cancer cells was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The effect of miR-203 on 95-D cell proliferation was analyzed using flow cytometry. The consequences of miR-203 expression on 95-D cell apoptosis were analyzed by Annexin V/propidium iodide double staining coupled with flow cytometry. The role of miR-203 in the invasive potential of 95-D cells was studied using a transwell chamber assay. A luciferase reporter gene system was used to verify that survivin is a target gene for miR-203. By qRT-PCR, the expression of miR-203 was lower in lung cancer cells than in normal bronchial epithelial cells (p < 0.01), and the expression of miR-203 in 95-D lung cancer cells was significantly higher after a 72-h transfection with the miR-203 precursor (p < 0.01). After a 72-h transfection with the miR-203 precursor, survivin protein levels in 95-D cells were significantly decreased (p < 0.01). Cell viability, as assessed with an MTT assay, decreased following an increase in miR-203 expression (p < 0.05). The flow cytometry results indicated that after miR-203 expression increased, the cell proliferation index decreased (p < 0.05) and the number of apoptotic cells increased (p < 0.01). Increased miR-203 expression led to a significant decrease in the number of cells that migrated through a transwell chamber membrane (p < 0.01). The luciferase reporter gene system demonstrated that the relative luciferase activity significantly decreased after transfection with the miR-203 precursor (p < 0.05). The expression of miR-203 is downregulated in lung cancer cells. miR-203 negatively regulates survivin protein expression and inhibits the proliferation and invasion of lung cancer cells. Therapeutic strategies that enhance miR-203 expression or silence survivin could potentially benefit lung cancer patients.