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Objective To explore the effects of HAVCR2 siRNA on apoptosis and cell cycle in the radiation-caused genomic instable liver cells.Methods RNAi was used to inhibit HAVCR2 gene transcription.Cellular apoptosis and cell cycle distribution were detected by flow cytometry (FCM).Expression of p53 gene was assayed by real time fluorescence quantitative PCR.Results HAVCR2 gene was effectively inhibited by RNAi (t =19.21,P ＜ 0.05).After siRNA transferring,cell apoptosis (t =3.65,P ＜ 0.05) and p53 gene expression (t =4.82,P ＜ 0.05) were decreased,and G2-phase arrest was induced(t =-3.41,P ＜ 0.05).Conclusion HAVCR2 siRNA can decrease the generation of apoptosis in the genomic instable liver cells and blocks the cells at G2 phase.

Objective To investigate the effect of CDT1 gene over-expression on the apoptosis and cell cycle distribution in liver cells with a characteristic of genomic instability induced by radiation(GIR).Methods Lentivirus particles were transferred into liver cells of GIR to up-regulate the expression of CDT1 gene.The apoptosis and the cell cycle were detected by flow cytometry (FCM).The expression changes of p53,ATM,ATR,Bcl-2,and Caspase-3 genes were analyzed by real-time fluorescence quantitative PCR.Results CDT1 gene was efficiently increased by the gene transfection(t =15.56,P ＜ 0.05).In the CDT1 over-expressed cells,while the apoptosis ratio was increased (t =4.19,P ＜ 0.05),the expressions of p53 and Bcl-2 gene were decreased (t =-4.21,-2.06,P ＜ 0.05),but the expression of ATM,ATR and Caspase-3 changed with no significant difference compared with control.Conclusions Over-expression of CDT1 could regulate genomic instability through apoptosis pathway and checkpoint independent of p53.

Objective To investigate the differential expression profile in the progeny of human liver cells surviving from ionizing radiation.Methods Complemental DNA gene chip was used to measure the transcriptional profile in progeny of HL-7702 cells exposed to 0, 2, 4, and 6 Gy of 60Co γ-rays, and the differentially expressed genes HAVCR2 and RAN were further identified by real-time PCR.Results The transcription level of 262 genes, 2746 genes and 3406 genes changed in the progeny of survival cells at 2, 4 and 6 Gy, respectively.A total of 71 common differentially expressed genes were screened, most of which were associated with transduction, cell cycle regulation, cellular immunity, cytoskeleton and movement, cell replication and repair mechanism.Conclusions Ionizing radiation could induce the expression changes of many genes, which might reveal the molecular mechanisms of gene expression in radiation induced genomic instability.

Objective To investigate the changes of proteomics in serum of Sprague-Dawley(SD) rats after accumulated irradiation with 137Cs γ-rays.Methods A total of thirty mature SD rats were randomly divided into three groups:0.2 Gy group,2 Gy group and healthy control group.Rats were irradiated at a dose rate of 0.336 mGy/min for 10 d and 20 d continuously.Isobaric tags for relative and absolute quantitation (iTRAQ) was used to analyze the different protein expression in serum of irradiated rats.Gene Ontology,KEGG pathway and protein-protein interaction network analysis were conducted using softwares.Results In total,363 protein spots were identified.Twenty nine proteins were differentially expressed in both groups compared with control,of which 10 proteins were up-regulated and 19 proteins were down-regulated.Based on the information of GO categories,these differentially expressed proteins were mainly located in the cytoplasm and membrane concerning the function of binding and catalytic activity.Analysis with the PAJEK software demonstrated that 16 differentially expressed proteins could form a complicated interaction network where glutathione S-transferase P1 (GSTP1),phosphoglycerate kinase 1 (PGK1) and protein disulfide-isomerase (PDI) might be key nodes.Conclusions Accumulated irradiation can induce differentially expressed proteins in serum of irradiated rats.Analysis on functional roles of the screened proteins GSTP1,PGK1 and PDI may provide insight into further mechanistic investigations and underlying molecular biomarkers induced by accumulated irradiation.

Objective To characterize the differential protein expression in the progeny of human liver ceils surviving from ionizing radiation by the proteomic analysis.Methods Two-dimensional electrophoresis gel coupled with mass spectrometry was used to explore the specific protein expression in the progeny of 7702 human liver cells surviving from ionizing radiation.Alterations in expression level of protein spots between the control and the progeny groups were statistically analyzed by ImageMaster 2D Platinum software and mass spectrometry was used to identify the protein spots with significantly altered expression-level.Results The progeny of irradiated ceils were derived from human liver cell line exposed to 0,2,4,6 Gy of 60Co γ-irradiatian.A total of 42 differentially expressed proteins between the control and the progeny of the irradiated cells groups were screened,of which 17 were identified by matrix assistant laser desorption ion-top off light-mass spectrometry(MALDI-TOF MS)analysis,including 4 up-regulated and 13 down-regnlated proteins.Conclusions The differentially expressed proteins profile could be significantly altered in the progeny of irradiated cells.The proteomics approach has the potential to detect the protein changes relevant to radiatian-induced genomic instability(RIGI).Further study of differentially expressed proteins would likely reveal the molecular mechanisms of gene expression in RIGI.

Objective To explore the effects of accumulated 60CD,γ-ray irradiation on small molecular metabolites in rats urine.Methods Ten healthy male SD rats were irradiated by 60Co γ-rays in 5 days and the accumulated doses were 0,0.2,0.4,0.6,0.8,1.0 Gy,respectively.The metabolites in urine of different groups were measured with 1 H-NMR combined with principal components analysis (PCA) and partial least square discriminate analysis (PLS-DA). Results The metabolites in rat urine were obviously changed after irradiation. Compared with control group,the amount of acetoacetate decreased after irradiation(t =29.7 -30.7,P ＜ 0.05 ),but its relative level was stable when the dose increased ( P ＞ 0.05 ).Meanwhile,the relative level of hippuric acid increased ( t =4.4 - 21.6,P ＜ 0.05 ) especially when the accumulated dose was higher than 1 Gy (t =21.6,P＜0.05). The relative level of proline,taurine and trimethylamine-N-oxide increased after irradiation with the same trend( t =3.5 - 13.4,4.7 - 11.5,2.9- 12.7,P＜0.05). Conclusions The acetoacetate,hippuric acid,proline,taurine,and trimethylamine-N-oxide may be applicable for biomarkers of accumulative irradiation on rat.

OBJECTIVE: To compare the effects of ~(56)Fe~(17+),~(12)C~(6+)ion beams and~(60)Co γ rays on chromosome aberration in human lymphoblastoid cells. METHODS: The human lymphoblastoid cells were divided into 0. 1,0. 3,0. 5,0. 7,1. 0,2. 0 Gy irradiated groups and 0. 0 Gy control group. They were separately exposed to ~(56)Fe~(17+)ion beams( linear energy transfer was 400. 0 ke V/μm),~(12)C~(6+)ion beams( linear energy transfer was 26. 0 ke V/μm) and~(60)C γ rays. Chromosome specimens were harvested 48 hours after irradiation. The effects of different radiation on dicentric plus centric ring( “d + r”) aberration rate and chromosome aberration in human lymphoblastoid cells were detected by light microscope with artificial counting. RESULTS: The “d + r”aberration rates induced by 0. 3-2. 0 Gy ~(12)C~(6+)ion beams were significantly higher than those of ~(56)Fe~(17+)ion beams and~(60)Co γ rays at the same dose( P < 0. 017). Chromosome aberration cell rates of 0. 1-2. 0 Gy ~(12)C~(6+)ion beams were significantly higher than those of ~(56)Fe~(17+)ion beams and~(60)C γ rays at the same dose( P < 0. 017). At the dose range of 0. 0-2. 0 Gy,chromosome aberration effects of three kinds of radiations were gradually increased( P < 0. 01). The relative biological effectiveness of ~(56)Fe~(17+)ion beams was lower than that of ~(12)C~(6+)ion beams.CONCLUSION: The chromosome aberration induced by ~(12)C~(6+)ion beams was more serious than that of~(60)Co γ rays and ~(56)Fe~(17+)ion beams.