Effects of different doses of lithium on the central nervous system in the rat valproic acid model of autism.

Epidemiological studies have shown that low doses of lithium in the environment can have beneficial effects on mental health. Autism spectrum disorder, a neurodevelopmental disorder in which patients exhibit abnormal behaviors, pharmacological interventions usually relied on a range of psychotropic medications. However, such medications often produce severe side effects or are ineffective in symptoms. Finding alternative ways to improve abnormal behaviors in individuals with autism are warranted, in which case lithium may be a relatively safe and effective medication. Lithium salt therapy is used to treat a variety of neuropsychiatric disorders and has neuroprotective effects. In this study, we investigated the effects of different doses of lithium on neurobehavioural disorders using the rat model of autism established by valproic acid (VPA) injection. Lithium was observed to have an ameliorative effect on the social cognitive, social memory and anxiety levels in the rat model of autism. Immunofluorescence staining showed that subchronic LiCl administration (1.0 mmol/kg) significantly reduced the number of Iba-1 positive cells in the CA1 region of the hippocampus in VPA group and brought it close to the levels of control group. Significantly lower levels of the pro-inflammatory marker IL-6 were observed in the hippocampus and serum after lithium treatment. In addition, the lithium treatment increased the levels of H3K9 acetylation in the hippocampus of VPA-exposed rats. The results showed a defensive effect of environment-related lithium exposure doses on neurobehavioural deficits in the rat valproic acid model of autism, suggesting that it may be a potential drug for the treatment of autism.

Exposure to a real traffic environment impairs brain cognition in aged mice.

Traffic-related air pollution (TRAP) has been a common public health problem, which is associated with central nervous system dysfunction according to large-scale epidemiological studies. Current studies are mostly limited to artificial laboratory exposure environments and specific genetic mechanisms remain unclear. Therefore, we chose a real-world transportation environment to expose aged mice, transporting them from the laboratory to a 1-m-high dry platform inside the campus and tunnel, and the mice were exposed daily from 7 a.m. to 7 p.m. for 2, 4 and 12 weeks respectively. Compared with the control group (in campus), the memory function of mice in the experimental group (in tunnel) was significantly impaired in the Morris water maze test. TRAP exposure increased the number of activated microglia in the hippocampal DG, CA1, CA3 regions and dorsolateral prefrontal cortex (dPFC). And neuroinflammation and oxidative stress levels were up-regulated in both hippocampus and dPFC of aged mice. By screening the risk genes of Alzheimer's disease, we found the mRNA and protein levels of ABCA7 were down-regulated and those of PYK2 were up-regulated. The DNA methylation ratios increased in four CpG sites of abca7 promoter region and decreased in one CpG site of pyk2 promoter region, which were consistent with the altered expression of ABCA7 and PYK2. In conclusion, exposure to the real traffic environment impaired memory function and enhanced neuroinflammation and oxidative stress responses, which could be relevant to the altered expression and DNA methylation levels of ABCA7 and PYK2. Our work provides a new and promising understanding of the pathological mechanisms of cognitive impairment caused by traffic-related air pollution.

Prenatal and postnatal traffic pollution exposure, DNA methylation in Shank3 and MeCP2 promoter regions, H3K4me3 and H3K27me3 and sociability in rats' offspring.

BACKGROUND: Road traffic air pollution is linked with an increased risk of autistic spectrum disorder (ASD). The aim of this study is to assess the effect of exposure to prenatal or postnatal traffic-related air pollution combining concomitant noise pollution on ASD-related epigenetic and behavioral alternations on offspring. METHODS: A 2 × 2 factorial analysis experiment was designed. Wistar rats were exposed at different sites (L group: green space; H group: crossroads) and timings (E group: full gestation; P group: 21 days after birth) at the same time, and air pollutants of nitrogen dioxide (NO2) and fine particles (PM2.5) were meanwhile sampled. On postnatal day 25, brains from offspring of each group were extracted to determine the levels of DNA methylation in Shank3 (three parts: Shank3_01, Shank3_02, Shank3_03) and MeCP2 (two parts: MeCP2_01, MeCP2_02) promoter regions, H3K4me3 and H3K27me3 after three-chamber social test. Meanwhile, the Shank3 and MeCP2 levels were quantified. RESULTS: The concentrations of PM2.5 (L: 58.33 µg/m3; H: 88.33 µg/m3, P < 0.05) and NO2 (L: 52.76 µg/m3; H: 146.03 µg/m3, P < 0.01) as well as the intensity of noise pollution (L: 44.4 dB (A); H: 70.1 dB (A), P < 0.001) differed significantly from 18:00 to 19:00 between experimental sites. Traffic pollution exposure (P = 0.006) and neonatal exposure (P = 0.001) led to lower weight of male pups on PND25. Male rats under early-life exposure had increased levels of Shank3 (Shank3_02: timing P < 0.001; site P < 0.05, Shank3_03: timing P < 0.001) and MeCP2 (MeCP2_01: timing P < 0.001, MeCP2_02: timing P < 0.001) methylation and H3K4me3 (EL: 11.94 µg/mg; EH: 11.98; PL: 17.14; PH: 14.78, timing P < 0.05), and reduced levels of H3K27me3 (EL: 71.07 µg/mg; EH: 44.76; PL: 29.15; PH: 28.67, timing P < 0.001; site P < 0.05) in brain compared to those under prenatal exposure. There was, for female pups, a same pattern of Shank3 (Shank3_02: timing P < 0.001; site P < 0.05, Shank3_03: timing P < 0.001) and MeCP2 (MeCP2_01: timing P < 0.05, MeCP2_02: timing P < 0.001) methylation and H3K4me3 (EL: 11.27 µg/mg; EH: 11.55; PL: 16.11; PH: 15.44, timing P < 0.001), but the levels of H3K27me3 exhibited an inverse trend concerning exposure timing. Hypermethylation at the MeCP2 and Shank3 promoter was correlated with the less content of MeCP2 (female: EL: 32.23 ng/mg; EH: 29.58; PL: 25.01; PH: 23.03, timing P < 0.001; site P < 0.05; male: EL: 31.05 ng/mg; EH: 32.75; PL: 23.40; PH: 25.91, timing P < 0.001) and Shank3 (female: EL: 5.10 ng/mg; EH: 5.31; PL: 4.63; PH: 4.82, timing P < 0.001; male: EL: 5.40 ng/mg; EH: 5.48; PL: 4.82; PH: 4.87, timing P < 0.001). Rats with traffic pollution exposure showed aberrant sociability preference and social novelty, while those without it behaved normally. CONCLUSIONS: Our findings suggest early life under environmental risks is a crucial window for epigenetic perturbations and then abnormalities in protein expression, and traffic pollution impairs behaviors either during pregnancy or after birth.

Hair levels of heavy metals and essential elements in Chinese children with autism spectrum disorder.

BACKGROUND: Disproportional heavy metals and essential elements were reported in children with autism spectrum disorder (ASD) that is obscure in etiology. Inevitably, the association is biased by diet and environmental factors. METHODS: Fifty pairs, one with ASD and the other living together from the same special school with cerebral palsy (CP), were recruited in Hangzhou (China), aged from 2 to 11 years old (74.0 % male). All samples were divided into two subgroups: preschool-aged (2-5 years old) and school-aged (6-10 years old). Heavy metals (As, Hg, Pb) and essential elements (Al, Ca, Cu, Mg, Mn, Zn) in hair were quantified by inductively coupled plasma mass spectrometry analysis and flame atomic absorption spectroscopy. RESULTS: The children with ASD generally had lower hair levels of Mn (ASD 0.124 µg/g, CP 0.332 µg/g, P = 0.001) compared to the children with CP. After stratification for age, there were no significant differences detected in preschool-aged group. In school-aged group, the results exhibited the children with ASD had higher hair Pb (1.485 µg/g, 0.690 µg/g, P = 0.007) and Cu/Zn ratio (0.092, 0.060, P = 0.003), while hair Hg (0.254 µg/g, 0.353 µg/g, P = 0.016)、Mn (0.089 µg/g, 0.385 µg/g, P = 0.002)、Mg (17.81 µg/g, 24.53 µg/g, P = 0.014) and Zn (100.15 µg/g, 135.83 µg/g, P = 0.007) showed an opposite pattern. CONCLUSIONS: These results suggest an imbalance of Mn in Chinese children with ASD.

Dose- and time- effect responses of DNA methylation and histone H3K9 acetylation changes induced by traffic-related air pollution.

As an important risk factor of respiratory disorders, traffic-related air pollution (TRAP) has caused extensive concerns. Epigenetic change has been considered a link between TRAP and respiratory diseases. However, the exact effects of TRAP on epigenetic changes are still unclear. Here we investigated the dose- and time- effect responses of TRAP on DNA methylations and H3K9 acetylation (H3K9ac) in both blood and lung tissues of rats. The findings showed that every 1 µg/m3 increase of TRAP components were associated with changes in %5 mC (95% CI) in LINE-1, iNOS, p16CDKN2A, and APC ranging from -0.088% (-0.150, -0.026) to 0.102 (0.049, 0.154), as well as 0.276 (0.053, 0.498) to 0.475 (0.103, 0.848) ng/mg increase of H3K9ac. In addition, every 1 more day exposure at high level of TRAP (in tunnel) also significantly changed the levels of DNA methylation (ranging from -0.842% to 0.248%) and H3K9ac (16.033 and 15.718 ng/mg pro in PBMC and lung tissue, respectively) changes. Season and/or sex could interact with air pollutants in affecting DNA methylation and H3K9ac. The findings showed that TRAP exposure is dose- and time- dependently associated with the changes of DNA methylation and H3K9ac.

[Effects of Traffic-related Air Pollution Exposure on DNA Methylation].

The goal of the present study was to explore the effects of traffic-related air pollution exposure on DNA methylation. Into five groups of 6, 30 healthy Wistar rats were randomly divided. Three groups of rats were then exposed to traffic-related air pollution at high (tunnel), moderate (crossroad), and low (control) pollution levels for 7 d, whereas the two other groups were exposed in the tunnel for 14 d/28 d. The levels of PM10 and NO2 were measured during the exposure. The study was performed in spring and autumn, and lung tissue and blood were collected after the exposure. Promoter methylation levels of p 53 , MGMT, and MAGE-A 4 were quantified via pyrosequencing. The levels of PM10 and NO2 in the crossroad and tunnel groups were significantly higher than those in the control group. After 7 d exposure in autumn, promoter methylation levels of p 53 and MGMT in lung tissue significantly decreased, and the methylation status continued to decrease with increasing exposure time; MAGE-A 4 was highly methylated and showed no difference among the three groups. DNA methylation in lung tissue was more likely to be changed compared with that in blood during 7 d exposure. As the exposure time increased, DNA methylation changes between blood and lung tissue started to coincide. In lung tissue, PM10 exposure was significantly associated with decreased p 53 promoter methylation (r=-0.347, P=0.038) and NO2 exposure was significantly associated with decreased promoter methylation of p 53, MGMT, and MAGE-A 4 (r=-0.482, -0.444, and -0.346, respectively; P< 0.05). In blood, PM10 and NO2 were significantly and positively associated with MAGE-A 4 promoter methylation (r=0.395 and 0.431, respectively; P< 0.05). Traffic-related air pollution exposure may induce promoter hypomethylation of p 53 and MGMT.

Cigarette Smoking, BPDE-DNA Adducts, and Aberrant Promoter Methylations of Tumor Suppressor Genes (TSGs) in NSCLC from Chinese Population.

Non-small cell lung cancer (NSCLC) is related to the genetic and epigenetic factors. The goal of this study was to determine association of cigarette smoking and BPDE-DNA adducts with promoter methylations of several genes in NSCLC. Methylation of the promoters of p16, RARß, DAPK, MGMT, and TIMP-3 genes of tumor tissues from 199 lung cancer patients was analyzed with methylation-specific PCR (MSP), and BPDE-DNA adduct level in lung cancer tissue was obtained by ELISA. Level of BPDE-DNA adduct increased significantly in males, aged people (over 60 years), and smokers; however, no significant difference was found while comparing the BPDE-DNA adduct levels among different tumor types, locations, and stages. Cigarette smoking was also associated with increased BPDE-DNA adducts level (OR = 2.43, p > .05) and increased methylation level in at least 1 gene (OR = 5.22, p < .01), both in dose-response manner. Similarly, cigarette smoking also significantly increase the risk of p16 or DAPK methylation (OR = 3.02, p < .05 for p16, and 3.66, p < .05 for DAPK). The highest risk of BPDE-DNA adducts was detected among individuals with cigarette smoking for more than 40 pack-years (OR = 4.21, p < .01). Furthermore, the present study did not show that BPDE-DNA adducts are significantly associated with abnormal TSGs methylations in NSCLC, including SCC and AdO, respectively. Conclusively, cigarette smoking is significantly associated with the increase of BPDE-DNA adduct level, promoter hypermethylation of p16 and DAPK genes, while BPDE-DNA adduct was not significantly related to abnormal promoter hypermethylation in TSGs, suggesting that BPDE-DNA adducts and TSGs methylations play independent roles in NSCLC.

H3K9 acetylation change patterns in rats after exposure to traffic-related air pollution.

Traffic-related air pollution (TRAP) has been acknowledged as a potential risk factor for numerous respiratory disorders including lung cancer; however, the exact mechanisms involved are still unclear. Here we investigated the effects of TRAP exposure on the H3K9 acetylation in rats. The exposure was performed in both spring and autumn with identical study procedures. In each season, 48 healthy Wistar rats were exposed to different levels of TRAP for 4 h, 7 d, 14 d, and 28 d, respectively. H3K9 acetylation levels in both the peripheral blood mononuclear cells (PBMCs) and lung tissues were quantified. Multiple linear regression was applied to assess the influence of air pollutants on H3K9 acetylation levels. The levels of PM2.5, PM10, and NO2 in the tunnel and crossroad groups were significantly higher than in the control group. The H3K9 acetylation levels were not significantly different between spring and autumn. When spring and autumn data were analyzed together, no significant association between the TRAP and H3K9 acetylation was found in 4h exposure window. However, in the 7 d exposure window, PM2.5 and PM10 exposures were associated with changes in H3K9 acetylation ranging from 0.276 (0.053, 0.498) to 0.475 (0.103, 0.848) per 1 µg/m(3) increase in the pollutant concentration. In addition, prolonged exposure of the rats in the tunnel showed that both PM2.5 and PM10 concentrations were positively associated with H3k9 acetylation in both PBMCs and lung tissues. The findings showed that 7-d and prolonged TRAP exposure could effectively increase the H3K9 acetylation level in both PBMCs and lung tissues of rats.

Characteristics of DNA methylation changes induced by traffic-related air pollution.

Traffic-related air pollution (TRAP) is a potential risk factor for numerous respiratory disorders, including lung cancer, while alteration of DNA methylation may be one of the underlying mechanisms. However, the effects of TRAP mixtures on DNA methylation have not been investigated. We have studied the effects of brief or prolonged TRAP exposures on DNA methylation in the rat. The exposures were performed in spring and autumn, with identical study procedures. In each season, healthy Wistar rats were exposed to TRAP at for 4 h, 7 d, 14 d, or 28 d. Global DNA methylation (LINE-1 and Alu) and specific gene methylation (p16(CDKN2A), APC, and iNOS) in the DNA from blood and lung tissues were quantified by pyrosequencing. Multiple linear regression was applied to assess the influence of air pollutants on DNA methylation levels. The levels of PM2.5, PM10, and NO2 in the high and moderate groups were significantly higher than in the control group. The DNA methylation levels were not significantly different between spring and autumn. When spring and autumn data were analyzed together, PM2.5, PM10, and NO2 exposures were associated with changes in%5mC (95% CI) in LINE-1, iNOS, p16(CDKN2A), and APC ranging from -0.088 (-0.150, -0.026) to 0.102 (0.049, 0.154) per 1 µg/m(3) increase in the pollutant concentration. Prolonged exposure to a high level of TRAP was negatively associated with LINE-1 and iNOS methylation, and positively associated with APC methylations in the DNA from lung tissues but not blood. These findings show that TRAP exposure is associated with decreased methylation of LINE-1 and iNOS, and increased methylation of p16(CDKN2A) and APC.

[Relationship between Line 1 methylation and clinical data of non-small cell lung cancer].

OBJECTIVE: To explore the impact of Line-1 methylation on clinical features of non-small cell lung cancer and its connection with smoking and other living habits. METHODS: Pyrosequencing was used to determine the extent of Line-1 methylation in cancer and adjacent tissues derived from 197 patients with primary non-small cell lung cancer. Non-conditional logistic regression analysis was performed to correlate the level of Line-1 methylation with clinical features and living habits of the patients. RESULTS: Line-1 methylation for cancer tissue and adjacent tissue has measured 68.20±11.63 and 78.90±2.09, respectively (P < 0.01), and has been associated with TNM staging, smoking history and histopathological types. CONCLUSION: Lung cancer tissue Line-1 methylation level is closely related with clinical features and smoking. There is also a correlation between histopathological types of lung cancer and relative hypomethylation of Line-1.

Aberrant promoter methylation of cell adhesion-related genes associated with clinicopathologic features in non-small cell lung cancer in China.

PURPOSE: The aim of this study was to investigate the methylation status of three cell adhesion-related genes including CDH1, TSLC1 and TIMP3 in non-small cell lung cancer and explore its association with clinicopathologic features and various environmental risk factors. METHODS: We detected the aberrant methylation presence of these genes by methylation-specific polymerase chain reaction and analyzed the potential correlations with multivariate logistic regression model as well as stepwise logistic regression. RESULTS: For CDH1, promoter methylation was less frequent in adenosquamous carcinomas than adenocarcinomas (OR=0.35, 95%CI=0.13-0.96); pickled food increased the methylation frequency (OR=2.23, 95%CI=1.09-4.54) while light smoking and fruit intake decreased that (OR=0.43, 95%CI=0.19-0.97; OR=0.37, 95%CI=0.15-0.95). For TSLC1, males and toxin exposure increased methylation frequency (OR=6.25, 95%CI=1.05-37.13; OR=2.42, 95%CI=1.01-5.77) while light smoking and radiation exposure decreased that (OR=0.14, 95%CI=0.03-0.60; OR=0.17, 95%CI=0.04-0.87). For TIMP3, males showed lower methylation frequency than females (OR=0.18, 95%CI=0.04-0.88) while central lung cancer, heavy smoking and radiation exposure presented higher aberrant DNA methylation status (OR=2.19, 95%CI=1.07-4.52; OR=6.99, 95%CI=1.32-37.14; OR=2.30, 95%CI=1.04-5.08). CONCLUSIONS: Aberrant promoter methylation of cell adhesion-related tumor suppressor genes in lung cancer displayed varieties of gene-specific correlations with clinicopathologic features and various environmental risk factors.

[Lung cancer and its epigenetics association with chronic obstructive pulmonary disease].

Lung cancer and chronic obstructive pulmonary disease (COPD) are the leading causes of morbidity and mortality worldwide. Development of lung cancer involves both genetic and environment factors. In addition to genetic alterations, epigenetic mechanism is closely involved in pathogenesis of lung cancer. Characterized by an abnormal persistent inflammatory response to noxious environmental stimulation, COPD has shown to increase the susceptibility for lung tumorigenesis in previous research. Current research on epigenetics of lung cancer and COPD has focused on aberrant DNA methylation, histone acetylation and non-coding RNAs regulation. The aberrant DNA methylation associated with lung cancer and COPD has included overexpression of DNA methyltransferase, global DNA hypomethylation and DNA hypermethylation in promoter regions, while histone acetylation and histone methylation are the major changes for histone modification, in which histone acetyltransferases, histone deacetylases, histone methyltransferases and histone demethylases play the most important roles. RNA interference and microRNAs are both hot topics of research on non-coding RNAs regulation. Understanding of concurrent epigenetic alterations in the pathogenesis of lung cancer and COPD may facilitate identification of specific therapeutic targets and development of effective treatment.

[Effects of 5-Aza-2-deoxycytidine on DNA methylation of anti-oncogenes in non-small cell lung cancer cells].

OBJECTIVE: To observe the expression of SFRP1 gene methylation in non-small cell lung cancer (NSCLC), and study the effect of 5-Aza-2-deoxycytidine (5-Aza-CdR) on DNA methylation and expression of SFRP1, p16 and MGMT genes in the human lung cancer cell line SPC-A-1 cells. METHODS: SP immunohistochemistry and methylation-specific PCR were used to detect the SFRP1 methylation in 60 NSCLC cases, and 21 cases of benign lung diseases were used as control group. SPC-A-1 cells were cultured and treated with 5-Aza-CdR. The promoter methylation status of SFRP1, p16 and MGMT genes were detected by methylation-specific polymerase (MSP) chain reaction, and mRNAs were detected by real-time PCR. RESULTS: The positive rate of SFRP1 gene methylation in NSCLC was significantly higher than that in normal lung tissue (58.3% vs. 14.3%; χ(2) = 12.118, P = 0.001). SFRP1 gene methylation was closely correlated with lymph node metastasis and degree of differentiation in NSCLC (P < 0.05). SFRP1 protein expression was correlated with clinical stage, degree of differentiation and lymph node metastasis in NSCLC (P < 0.05). The positive expression of SFRP1 protein in 30 cases of NSCLC tissue containing SFRP1 gene methylation was significantly higher than that in non-methylated NSCLC (68.6% vs. 24.0%; χ(2) = 9.613, P = 0.002). SFRP1 gene methylation was closely correlated with SFRP1 gene protein expression in NSCLC (P < 0.05). Negative expression of SFRP1 protein was correlated with the differentiation, clinical stage, and lymph node metastasis in NSCLC (all P < 0.05). Without 5-Aza-CdR treatment, the expressions of methylation of SFRP1, p16 and MGMT genes and their mRNA were low. After 5-Aza-CdR treatment at different concentrations, their expressions were significantly elevated (all P < 0.05). CONCLUSIONS: SFRP1 gene methylation is closely associated with carcinogenesis and development of NSCLC. 5-Aza-CdR may reverse the methylation of SFRP1, p16 and MGMT genes, and facilitate the re-expression of the anti-oncogenes.

[Correlation between RARbeta gene promoter methylation and P53 gene mutations in non-small cell lung cancer].

OBJECTIVE: To investigate the correlation between RARbeta gene promoter methylation and P53 gene mutations in non-small cell lung cancer (NSCLC). METHODS: Promoter methylation of RARbeta and P53 mutations of exons 5 through 9 in 198 resected primary NSCLC tissues were determined by methylation-specific PCR and direct sequencing. RESULTS: RARbeta gene promoter methylation and P53 mutation were detected in 58.1% and 36.4% of tumors, respectively. Both were higher in males than in females and in smokers than in nonsmokers. A higher prevalence of RARbeta promoter methylation was found in patients with advanced stage tumors than those with TNM stage I. P53 gene mutations were more frequent in squamous cell carcinoma and adeno-squamous carcinoma than adenocarcinoma. All such differences were statistically significant (P< 0.05). Frequencies of P53 mutations, including G:C>T:A mutations, transversions and missense mutations were significantly higher in tumors with RARbeta methylation than in those without (P< 0.05). A significantly higher prevalence of RARbeta methylation was found in tumors with only G:C>T:A mutation in P53 gene than those without P53 mutations (P< 0.05). This difference (OR=3.737, 95%CI: 1.414-9.873) was still statistically significant (P< 0.05) in smokers (OR=4.020, 95%CI: 1.263-12.800), squamous cell carcinomas (OR=5.480, 95%CI: 1.400-21.446) or patients with advanced tumors (OR=3.446, 95%CI: 1.054-11.267) after adjusting for age and sex. CONCLUSION: RARbeta methylation is associated with G:C>T:A mutations in P53 gene in NSCLC.

[Effects of CYP1A1 and GSTM1 gene polymorphisms and BPDE-DNA adducts on lung cancer].

OBJECTIVE: To investigate the effect of CYP1A1 and GSTM1 genetic polymorphisms and BPDE-DNA adducts on lung tumorigenesis. METHODS: The case control study has included 200 cases of lung cancer and 200 controls. DNA was extracted from blood samples of all subjects. The genotype of both CYP1A1 and GSTM1 were detected with PCR-based restriction fragment length polymorphisms (PCR-RELP). BPDE-DNA adducts were detected with competitive ELISA. RESULTS: CYP1A1 mutant genotype and GSTM1 null genotype with smoke has increased the risk of lung cancer, with OR being 2.406(1.321-4.382), 2.755(1.470-5.163), respectively. The level of BPDE-DNA adducts in patients was greater than control, and the adduct level in ever smokers was higher than never smokers, the difference was statistically significant (P= 0.0252). GSTM1 null genotype individuals with BPDE-DNA level higher than 5 adducts/10(8) nucleotide have increased risk of lung cancer (OR= 1.988, 95%CI: 1.011-3.912). Compared with never smokers with CYP1A1 wild genotype, smokers with CYP1A1 mutation genotype had an increased risk of forming a higher level of DNA adducts (P= 0.0459). Smokers with GSTM1 null genotype formed more DNA adducts compared with never smokers with GSTM1 functional genotype (OR = 2.432, 95% CI: 1.072-4.517). CONCLUSION: GSTM1 null genotype with higher level DNA adducts may increase the risk of lung cancer. DNA adducts form easier in smokers with CYP1A1 mutation genotype and GSTM1 null genotype, which in turn may influence lung tumorigenesis.

Effect of CYP1A1 MSPI polymorphism on the relationship between TP53 mutation and CDKN2A hypermethylation in non-small cell lung cancer.

BACKGROUND AND AIMS: The molecular mechanisms of lung cancer susceptibility have not been fully understood. Although it has been described that germline polymorphisms are associated with either mutation or methylation of genes, the link between gene polymorphisms and gene-gene interactions has not been investigated. Therefore, we conducted this study to determine whether CYP1A1/GSTM1 polymorphisms can affect the relationship between TP53 mutation and CDKN2A hypermethylation in lung cancer. METHODS: This study included 196 primary non-small cell lung cancer (NSCLC) patients. CYP1A1 MSPI and GSTM1 polymorphisms were characterized through PCR-RFLP on DNA isolated from peripheral lymphocytes. TP53 mutations of exons 5 through 9 and CDKN2A promoter hypermethylation in both cancer tissues and corresponding normal tissues were analyzed by direct sequencing and methylation-specific PCR (MSP) respectively. RESULTS: TP53 mutation in the tumor was associated with squamous cell histology and CDKN2A methylation was associated with older age (≥60 years), heavy smoking (>30 pack-years), squamous cell histology and advanced stage (stage II-IV). After adjusting for age, sex, smoking degree, histology type and TNM stage, the correlation between TP53 mutation and CDKN2A methylation was significant in patients with CYP1A1 risk genotype (p = 0.038), but not in those with CYP1A1 homogeneity wild genotype (p = 0.151). CONCLUSIONS: This may suggest that TP53 mutation and CDKN2A methylation specifically interact to promote lung tumorigenesis in subjects with CYP1A1 risk genotype but not in those with CYP1A1 wild-type homozygotes, implying different pathways for the development of lung carcinoma with respect to CYP1A1 polymorphism.

[Current progress in research on epigenetic effects of air pollution].

Air pollution is associated with numerous diseases. In recent years,researches have increasingly showed that epigenetic modifications usually occur at the early stage of diseases, and make greater contributions to the occurrence and development of diseases compared to genetic abnormalities. Thus, researches on epigenetic effects of air pollution would serve for better understanding the interaction between air pollutants and genome in the pathogenesis of disease. Meanwhile, in order to reduce the exposure to air pollution and diminish the adverse effects related, further studies are needed to identify epigenetic biomarkers of air pollution so that we can take timely and effective measures in disease prevention.

[Relationship between promoter methylation of p16, DAPK and RAR beta genes and the clinical data of non-small cell lung cancer].

OBJECTIVE: To investigate the effects of promoter methylation of p16, death-associated protein kinase (DAPK) and retinoic acid receptor-beta (RAR beta) genes on clinical data in non-small cell lung cancers, and to study the effect of smoking on the risk of gene methylation. METHODS: The promoter methylation of p16, DAPK and RAR beta genes in 200 primary non-small cell lung cancers and the corresponding nonmalignant lung tissues were determined by methylation-specific PCR. RESULTS: Methylation in the tumor tissues was detected in 51.0% for p16, 60.0% for DAPK, and 58.0% for RAR beta gene, with significant differences (P < 0.05) when compared with those in the corresponding nonmalignant tissues(12.5%, 11.5% and 15.0%) respectively. p16 gene methylation in tumor tissue was associated with age significantly in unconditional logistic regression analysis (P < 0.01) and histologic type (P < 0.05). DAPK gene methylation in tumor tissue was associated significantly with age (P < 0.05), gender (P < 0.05) and clinical type (P < 0.05). RAR beta gene methylation in tumor tissue was associated with clinical type (P < 0.05) and tumor stage (P < 0.05) significantly. The interaction odds ratio (OR) for the gene-gene interaction in tumor tissue between p16 and DAPK was 1.987 (95%CI:1.055-3.743). The results of the gene-smoking analyses revealed that a relationship existed between cigarette smoking and p16 gene methylation (OR = 3.139, 95%CI: 1.046-9.419), the OR for the relationship of DAPK gene methylation and cigarette smoking was 3.585(95%CI: 1.270-10.123) in tumor tissue. The RAR beta gene methylation did not differ based on the smoking status of patients in tumor tissue. CONCLUSION: The p16, DAPK and RAR beta genes methylation are strongly associated with clinical data of non-small cell lung cancer, and methylation of p16 and DAPK genes are associated with tobacco smoking.

Combined effects of serum trace metals and polymorphisms of CYP1A1 or GSTM1 on non-small cell lung cancer: a hospital based case-control study in China.

INTRODUCTION: The limited information for effects of serum trace elements and genetic polymorphisms on lung cancer is available. Based on a hospital based case-control study, the epidemiological questionnaires were completed by face to face interview, and the gene polymorphisms were tested by RFLP-PCR, and serum trace metals were measured by atomic absorption spectrophotometer, and the data was analyzed by the logistic regressive models. RESULTS: The high serum copper level (>1500 ng/ml) or serum copper/zinc ratio (>1) was the risk factors of NSCLC (OR=3.10, 11.03, respectively), but the ORs of the higher serum Zn (>1200 ng/ml), Se (>50 ng/ml) or Cr(3+) (>600 ng/ml) for NSCLC were all significantly less than 0.20 (all p<0.01) indicating strong protection against NSCLC. While the OR of CYP 1A1 variants carriers with a higher serum Cu or Cu/Zn ratio level was around 3.38 and 12.59, respectively, the risk of CYP1A1 variants carriers with a higher serum Zn is 0.18, Se 0.04 or Cr(3+) 0.28. Similarly, compared with the carriers of GSTM1 power with a lower serum Zn, Se or Cr(3+), the OR of the carriers of GSTM1 null with a higher serum Zn, Se and Cr(3+) was separately 0.16, 0.07 and 0.26, highlighting the protection against NSCLC. CONCLUSIONS: Our findings suggested that CYP1A1 or GSTM1 variants may significantly modify the associations between level of serum trace metals (Cu, Zn, Se or Cr) and NSCLC, indicating the intriguing pathogenesis of lung cancer.

[Some research development on non-small cell lung cancer genetics and genetic expression].

Non-small cell lung cancer is the major cancer causing death among the malignant tumors. Early detection non-small cell lung cancer can detect the patients in time and get the treatment in time, to obtain the relative good therapy results. So, it is necessary to develop a method being able to accurately determine the non-small cell lung cancer at the early stage. Currently, the lung cancer marker detection is of certain importance in the non-small cell lung cancer diagnosis. Large volume of molecular biology research demonstrate that gene polymorphism is the important factor of the lung cancer occurrence. Furthermore, the importance of genetic expression changes that occur during lung cancer development has been realized gradually. In the future non-small lung cancer research, a comprehensive method combing epidemiological, genetic and genetic expression research seems very important.