Effect of nano-SiO_2 on the survival and PARP-1 expression in 16HBE cells / 中国职业医学

OBJECTIVE: To explore the effects of nano-silicon dioxide( SiO_2) on the survival and poly( ADP-ribose)polymerase-1( PARP-1) expression in human bronchial epithelial cells( 16 HBE cells). METHODS: i) The 16 HBE cells were treated with nano-SiO_2 at concentrations ranging from 0 to 100 mg/L for 24. 0 hours,and CCK-8 assay was used to examine cell viability. ii) The 16 HBE cells were divided into 6 groups: solvent control group( equal volume solvent treatment),micro-SiO_2 control group( treated with 20 mg/L micro-SiO_2),5,10,and 20 mg/L nano-SiO_2 groups( treated with the corresponding final dose of nano-SiO_2),and curcumin group. The curcumin group was given pretreatment with curcumin at a final concentration of 10 μmol/L for 2. 0 hours followed by treatment with a final concentration of 20 mg/L of nano-SiO_2. Cells in each group were harvested at time points of 4. 0,12. 0 and 24. 0 hours after treatment. The relative expression of PARP-1 mRNA and protein in 16 HBE cells was detected by quantitative real-time polymerase chain reaction and Western blotting respectively. RESULTS: i) The survival of 16 HBE cells decreased with increasing nano-SiO_2 treatment dose,showing a dose-effect relationship( P < 0. 01). ii) The expression of PARP-1 mRNA and protein in 16 HBE cells were dose-dependently decreased after nano-SiO_2 stimulation at the 12. 0 and 24. 0 hours time points( P < 0. 01). The expression of PARP-1 mRNA and protein in 5,10,and 20 mg/L nano-SiO_2 groups decreased at the above mentioned time points( P < 0. 05),compared with the solvent control group at the same time points. The expression of PARP-1 mRNA and protein in 20 mg/L nano-SiO_2 group was lower than that in the micro-SiO_2 control group at the same 12. 0 and 24. 0 hours time point( P < 0. 05). The above two indexes of cells were higher in curcumin group than that of 20 mg/L nano-SiO_2 group at the 12. 0 hours time point( P < 0. 05). CONCLUSION: Nano-SiO_2 stimulation can lead to decrease survival of 16 HBE cells in a dose-dependent manner and down-regulation of PARP-1 expression may be one of the mechanisms of proliferation and inhibition of 16 HBE cells induced by nano-SiO_2. Curcumin has certain protective effect on nano-SiO_2-induced 16 HBE cell injury.

Changes of the expression for genes related with senescence and the telomerase activity during cellular replicative and premature senescence in human embryonic lung fibroblasts / 中华劳动卫生职业病杂志

Objective@#To detect the alterations of telomerase activity and the expression for oxidative stress responsive genes related with senescence during cellular replicative senescence and hydrogen peroxide-induced premature senescence in human embryonic lung fibroblasts (HELFs) in vitro.@*Methods@#The HELFs were divided into young cells (22 population doubling levels, 22PDL) , mid-aged cells (35PDL) and replicative senes-cent cells (49PDL) and premature senescent cells induced by H2O2(premature senescence, PS). The telomerase activity was detected by ELISA assay during cellular replicative and premature senescence. The mRNA level of oxidative stress responsive genes related with senescence for Foxo1, Foxo3, Pdx1, apoA-I and MMP1 was per-formed by RT-Q-PCR separately.@*Results@#The mRNA level for Foxo1, Foxo3, apoA-I and Pdx1 was decreased separately during cellular replicative senescence compared to that in the young-stage cells with statistical signifi-cance (P<0.05). The expression of MMP1 was up-regulated 5.1-fold obviously (P<0.05). In premature senes-cence, the mRNA level was only decreased for Foxo1, Foxo3 and apoA-I, but up-regulated 2.3-fold and 6.2-fold for Pdx1 and MMP1 respcetively vs 22PDL significantly (P<0.05). The telomerase activity in young cells was not detected, and it increased in mid-aged cells and replicative senescence stages during cellular replicative se-nescence as compared to 22PDL with statistical significance (P<0.05). The telomerase activity in premature se-nescence was highly active.@*Conclusion@#The expression for genes related with senescence has differences be-tween replicative and premature senescence and hydrogen peroxide modifies their expression levels. The telomer-ase activity has been going up with increased PDLs.

Effect of silicon dioxide nanoparticles on expression and DNA methylation of PARP-1 gene in HaCaT cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effect of silicon dioxide nanoparticles on the expression and promoter region CpG islands methylation of (Poly [ADP-ribose] polymerase 1, PARP-1) gene in human HaCaT Cell.</p><p><b>METHODS</b>HaCaT Cells were treated with nm-SiO₂at 0, 2.5, 5 and 10 µg/mL and micro-SiO₂at 10 µg/ml for 24 h and DAC treatment was given at 10 µg/ml group for 48 h. Real-time PCR and western blot assay was used to detect the expression of PARP-1 mRNA and protein. BSP (Bisulfite Pyrosequence, BSP) assay was used to detect the promoter region CpG islands methylation status of PARP-1 gene.</p><p><b>RESULTS</b>After exposure to nano-SiO₂particles, compared to CTRL group, the mRNA and protein expression of PARP-1 in micro-SiO₂and 2.5 µg/ml group unchanged, but he mRNA and protein expression of PARP-1 in 5, 10 µg/ml as well as DAC group was down-regulated and there are statistical significance between CTRL group and 5, 10 µg/ml as well as DAC group and the PARP-1 promoter region CpG islands showed methylation.</p><p><b>CONCLUSION</b>nano-SiO₂can down-regulate PARP-1 expression in HaCaT Cell and this is associated with the change in the methylation of PARP-1 gene promoter region CpG islands induced by nano-SiO₂particles.</p>

Investigation of trichloroethylene-induced effects on subcellular proteomes in L-02 hepatic cells / 中华预防医学杂志

<p><b>OBJECTIVE</b>To put the insight into the trichloroethylene (TCE)-induced effect on the differential expression of subcellular proteins in human normal liver cell line (L-02).</p><p><b>METHODS</b>The membrane proteins and nuclear proteins of TCE-treated (8.0 mmol/L) group and controls were extracted by subcellular proteome extraction kit, respectively. The TCE-induced differentially expressions were analyzed by a two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization tandem time-of-flight spectrometry (MALDI-TOF-MS). Bioinformatics analysis was used to reveal the biological processes and predict transmembrane domains of differential expressed proteins. The expression of ATP synthase subunit beta (ATP5B), heterogeneous nuclear ribonucleoprotein H2 (hnRNP H2) and far up steam element-binding protein 1 (FUBP1) were measured under TCE treatment by Western blot.</p><p><b>RESULTS</b>After TCE treatment for 24 h in L-02 cells, 14 membrane proteins and 18 nuclear proteins were identified as differential expression. After treated with TCE in concentrations of 0, 2.0, 4.0 and 8.0 mmol/L for 24 h, the relative levels of ATP5B expression were 1.00±0.03, 1.21±0.14, 1.25±0.12 and 1.48±0.17 (F = 8.51, P = 0.007), the relative levels of hnRNP H2 expression were 1.00±0.09, 1.22±0.15, 1.43±0.21, 1.53±0.17 (F = 6.57, P = 0.015), respectively; the relative levels of FUBP1 expression were 1.00±0.11, 0.91±0.07, 0.73±0.04 and 0.67±0.03 (F = 15.81, P = 0.001), respectively, which were consistent with the results in proteomics. The bioinformatics analysis showed that the most dominant biological process were involved in RNA processing (10 proteins, P = 2.46×10(-6)), especially in RNA splicing (9 proteins, P = 1.77×10(-7)).</p><p><b>CONCLUSION</b>The exposure of TCE could alter the expression of membrane proteins and nuclear proteins in L-02 cells. These abnormal expressed proteins involved in RNA splicing would provide novel clues for further understanding of TCE-induced hepatotoxicity.</p>

Effect of bisphenol A on differentiation potential of mouse embryonic stem cells / 中国药理学与毒理学杂志

OBJECTIVE To explore the effect of bisphenol A (BPA) on the differentiation potential of embryonic stem cells, and provide an experimental basis for evaluation of safety of BPA. METHODS Mouse embryonic fibroblasts (MEFs) and embryonic stem cells (ESCs) were treated with BPA 0.1, 1, 10, 100 and 1000 μmol.L-1 for 8 d respectively. The viability of MEFs and ESCs was measured by CCK-8 and lC50 was calculated. The mRNA expression of α-myosin heavy chain in ESCs was tested by RT-PCR to determine lD50 . The embryonic body cultured by suspension method was treated with BPA 0.001, 0.01, 0.1 and 1 μmol.L-1 for 10 d respectively. The changes of marked genes in each blastoderm were detected by RT-PCR. RESULTS lC50 of BPA to mouse ESCs was 5.22×10-4 mol.L-1 , and to MEFs was 6. 25 × 10-4 mol.L-1 . lD50 of BPA to mouse ESCs differentiating to cardiomyocytes was 7.0×10-7 mol.L-1 . BPA 0.001 and 0.01 μmol.L-1 upregulated the expression of the marked genes of mesoderm, fetal liver kinase-1 and globin transcription factor 1. CONCLUSION BPA is a strong embry-otoxic compound. BPA of low concentration can promote the differentiation of mouse ESCs to mesoderm.

Hedgehog signaling pathway in chemocarcinogenesis and progression of breast cancer / 中国药理学与毒理学杂志

The controversial results of several studies suggest that certain everyday-use chemicals may be linked to breast cancer. ln recent years, extensive researches have been carried out to under-stand breast carcinogenesis and the hedgehog(Hh) signaling pathway has emerged as a critical determi-nant of human breast cancer. Aberrant Hh signaling in adults results in carcinogenesis, angiogenesis, and metastasis. This review is focused on the Hh signaling pathway and chemicals in the regulation of breast cancer development and provide an updated survey of pre-clinical and clinical trials of novel strategies to target them.

Effect of poly-ADP-ribosylation on the alteration of DNA methylation level of human bronchial epithelial cells induced by Cr (VI) / 中华预防医学杂志

<p><b>OBJECTIVE</b>To reveal the role of poly-ADP-ribosylation and DNA methylation in carcinogenic process induced induced by Cr (VI), and to discuss the relations between them.</p><p><b>METHODS</b>The pre-established Poly (ADP-ribose) glycohydrolase (PARG) deficient cells and 16HBE cells were treated with different concentrations of Cr (VI), and the changes of total genomic DNA methylation level in different groups were detected by methylation immunofluorescent detection, as well as the changes of the activity of methyltransferases. Moreover, RT-PCR and western blotting method were applied to analyze the changes of expression of DNMT1, DNMT3a, DNMT3b and MBD2, upon the protein level.</p><p><b>RESULTS</b>After treated by Cr(VI) for 24 h, the healthy 16HBE cells showed a significant lower level of genomic DNA methylation; however, there was no significant changes (P > 0.05) found in PARG deficient cells by immunofluorescence assay. When the dose of Cr (VI) reached 5.0 µmol/L, the activity of methyltransferases in 16HBE cells and PARG deficient cells (49.33 ± 2.65, 80.05 ± 2.05) decreased by 20% and 50% comparing with contrast group (99.27 ± 1.10, 99.30 ± 0.60) . After treated by Cr (VI) for 24 h, the expression of mRNA and protein level among DNMT1, DNMT3a, DNMT3b and MBD2 decreased significantly in healthy 16HBE cells; and the expression of DNMT1 and DNMT3a decreased in PARG deficiency cells. The relevant expression levels of mRNA of DNMT1 were separately (0.99 ± 0.09), (0.79 ± 0.10), (0.59 ± 0.13) and (0.39 ± 0.02) (F = 247.17, P < 0.01), the expression levels of protein were separately (1.00 ± 0.03), (0.69 ± 0.15), (0.65 ± 0.10) and (0.55 ± 0.13) (F = 214.12, P < 0.01), the expression levels of DNMT3a mRNA were separately (1.00 ± 0.04) , (0.93 ± 0.11) , (0.79 ± 0.07) , (0.59 ± 0.05) (F = 498.16, P < 0.01) , and the expression levels of protein were separately (1.00 ± 0.14) , (0.97 ± 0.11) , (0.79 ± 0.17) , (0.57 ± 0.15) (F = 390.11, P < 0.01) when the dose of Cr (VI) at 0, 0.3, 1.2 and 5.0 µmol/L. However, there were no significant changes of expression found in DNMT3b and MBD2.</p><p><b>CONCLUSION</b>Poly-ADP-ribosylation could regulate the activity of DNMT3b and MBD2, protect cells against the DNA methylation alteration induced by Cr(VI) and maintain the global genomic DNA methylation level.</p>

Investigation of the action mechanisms of poly-ADP-ribosylation in hexavalent chromium induced cell damage / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of poly-ADP-ribosylation in hexavalent chromium Cr(VI) induced cell damage.</p><p><b>METHODS</b>The study object, poly (ADP-ribose) glycohydrolase (PARG) deficient human bronchial epithelial cells (16HBE cells), was constructed previously by our research group. Normal 16HBE cells and PARG-deficient cells were treated with different doses of Cr (VI) for 24 h to compare the differences to Cr (VI) toxicity, meanwhile set up the solvent control group. On this basis, 5.0 µmol/L of Cr (VI) was selected as the exposure dose, after the exposure treatment, total proteins of both cells were extracted for two dimension fluorescence difference gel electrophoresis (2D-DIGE) separation, statistically significant differential protein spots were screened and identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS/MS), and further validated by Western blot.</p><p><b>RESULTS</b>After Cr (VI) treatment, the survival rate of PARG-deficient cells was higher than normal 16HBE cells. When the doses reached up to 5.0 µmol/L, the survival rate of 16HBE cells and PARG-deficient cells were respectively (59.67 ± 6.43)% and (82.00 ± 6.25)%, the difference between which was significant (t = -4.32, P < 0.05). 18 protein spots were selected and successfully identified after 2D-DIGE comparison of differential proteins between normal 16HBE cells and PARG-deficient cells before and after exposure. The function of those proteins was involved in the maintenance of cell shape, energy metabolism, DNA damage repair and regulation of gene expression. The differential expression of cofilin-1 was successfully validated by Western blot. The expression level of cofilin-1 in the 16HBE cells increased after Cr (VI) exposure with the relative expression quantity of 1.41 ± 0.04 in treated group and 1.00 ± 0.01 in control group, the difference of which was statistically significant (t = -18.00, P < 0.05), while the expression level in PARG-deficient cells had no statistically significant difference (t = -8.61, P > 0.05).</p><p><b>CONCLUSION</b>Most of the identified differential proteins are closely related to tumorigenesis, suggesting that poly-ADP-ribosylation reaction may resist the cytotoxicity of Cr(VI) by inhibiting Cr (VI) induced tumorigenesis, which provides important reference data to clarify the mechanisms of poly-ADP-ribosylation in Cr (VI) induced cell damage.</p>

X-ray repair cross complementing group 1 protects human bronchial epithelial cells from hydroquinone-induced DNA damage / 中国药理学与毒理学杂志

AIM To explore the molecular mechanism of hydroquinone genotoxicity in human bronchial epithelial cells and investigate whether human X-ray repair cross complementing group 1 (XRCC1)was involved in protecting cells from the damage caused by hydroquinone. METHODS XRCC1 gene was knocked down by RNA interference and XRCC1-deficient cell was established by transfected recombinant plasmid pEGFP-C1-pU6-dsRNA. Normal human bronchial epithelial cells (normal cells) and cells transfected with the empty vector of pEGFP-C1 (vector cells) were used as the normal control and vector control. All cells were treated with different concentrations of hydroquinone (10-100 μmol·L-1) for 4 h. MTT assay was used to test cell viability and comet assay was used to detect the DNA damage and repairment. RESULTS MTT assay showed that hydroquinone inhibited the growth of cells in a concentration-dependant manner and the survival number of XRCC1-deficient cell was less than that of the two control groups. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in XRCC1-deficient cell line than in control cells and there were no significant difference in the two control groups. CONCLUSION The results suggest XRCC1 be involved in preventing cells from damage caused by hydroquinone.

Distribution of poly(ADP-ribose) polymerase pseudogene polymorphism and association with susceptibility to lung cancer in Chinese people / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the distribution of poly(ADP-ribose) polymerase(PARP) pseudogene polymorphism and the association with susceptibility to lung cancer in Chinese people.</p><p><b>METHODS</b>The subjects of this study included 63 patients with lung cancer and 82 healthy controls matched in gender and age. Genome DNA was extracted from white blood cells. Products from PCR with a pair of specific primer were electrophoresized in agarose including EB. Under ultraviolet, observation and imaging were performed.</p><p><b>RESULTS</b>There was no significant difference in genotype between the cases and controls. The frequencies of B allele in cases and controls were 0.095 and 0.116 respectively. Whether there was B allele or not, smoking was a risk factor of lung cancer (P<0.05). As the genotype was AA and AB or BB, smoking OR was 2.28 and 4.83 respectively. Among non-smokers, the risk at lung cancer did not increase in AB or BB genotypes(P=0.202).</p><p><b>CONCLUSION</b>Frequency of B allele is relatively lower in Chinese people than in other races. In smokers, B allele may be a susceptible marker of lung cancer, and there is synergistic function between B allele and smoking.</p>

Detection of hMSH2 gene mutations in gynecologic tumor population by multiple PCR-SSCP / 中国癌症杂志

Purpose:To set up a new method to screen hMSH2 gene mutations, to detect hMSH2 gene mutations in gynecologic tumor population and to find molecular biomarkers of tumor. Methods:The basic data and blood samples from 42 gynecologic tumor patients werre collected. The genetic mutations of the sixth exon and seventh exon of hMSH2 gene were investigated by multiple polymerase chain reaction single strand conformation polymorphism (PCR SSCP),followed by DNA sequencing. Results:The successes in setting up the multiple PCR SSCP method made it possible to detect hMSH2 gene mutations more quickly and more economically. Two samples of the seventh exon mutation was detected in the tumor population. The mutation is Leu→Phe missense mutation. No mutation of the sixth exon was detected by SSCP.Conclusions:The multiple PCR SSCP method is effective in detecting genetic mutations. There is a mutation site in the seventh exon of hMSH2 gene. It is probably a biomarker of gynecologic tumor. This discovery might offer the basis for further investigation of mutations in large amount population and studies of the function of the mutation.

Effects of HQ on DNA and Cell Cycle of L-02 Hepatic Cells / 环境与健康杂志

0.05),whereas the survival rate in each group of 160 and 320 ?mol/L was significantly higher than that in the control(P