Objective: The effect of whole body irradiation (WBI) on B7-1 and B7-2 express ion in peritoneal macrophages in mice was observed.Methods:Immunohistochemistry (ABC method) was used. Results: The upregulation of B7-2 expression induced by WBI X-rays appeared ea r lier than that of B7-1.The study on the dose-effect relationship showed that t he ex pression of both B7-1 and B7-2 reached its peak at 0.075 Gy after WBI X-rays. Th e doses inducing a second peak of B7-1 and B7-2 upregulation were higher in th e case of WBI in comparison with in vitro irradiation. Conclusion: The results suggested that the upregulation of expression of B7 mole cules after irradiation might be an important factor involved in the enhancing e ffect of low dose radiation on immunity.

Objective To study whether or not CD40 gene is a target of miR-503 in U937 cells,and to observe the regulatory effects of miR-503 on expression of CD40 induced by irradiation in U937cells.Methods The miR-503 sequence was inserted into pcDNA-DEST-47 plasmid to construct the eukaryotic expression vector (pcDNA-DEST-miR-503) and to construct the CD40 gene 3′-UTR luciferase reporter plasmid (psiCHECK2-CD40) at the same time.They were used to transfect U937 cells together for analysis of the regulatory effects of miR-503 on the expression of CD40.Meanwhile the miR-203 and miR-29b were used as controls to observe whether or not CD40 gene was a target of miR-503.The expression change of CD40 after irradiation,and the inhibitory effect of miR-503 on the expression of CD40 was confirmed by Western blot assay.The expression of miR-503 was detected by real-time RT-PCR (qPCR) after irradiation with doses of 5.0 Gy.Results The expression of luciferase in the group of transfected with pcDNA-DEST-miR-503 and psiCHECK2-CD40 plasmids was significantly lower than that in the group transfected with empty plasmid and CD40 gene (t =3.16,P ＜ 0.05).And the miR-203 and miR-29b could not inhibit the activity of CD40 luciferase,but the miR-503 could significantly inhibit the activity of it (t =5.25,P ＜ 0.01 ).The expression of CD40 protein in U937 cells was decreased after the cells were transfected with pcDNA-DEST-miR-503.After irradiation with dose of 5.0 Gy,the expression of miR-503 were increased (t =3.63 - 17.00,P ＜0.01 ) and the expression of CD40 protein decreased.Conclusions The CD40 gene might be the target of miR-503,and miR-503 could regulate the expression of CD40 gene.Irradiation could up-regulate the expression of miR-503 and inhibit the expression of CD40 protein in U937 cells.miR-503 might play a role in the process of regulation of irradiation on expression of CD40 protein in tumor cells.

Objective To study the effect of small heterocyclic compound 8-oxo-3-thiomorpholino-8H-acenaphtho pyrrole-9-carbonitrile(S1) on apoptosis of human androgen independent prostatic carcinoma cells line(PC3) and its mechanism.Methods PC3 cells were cultivated,and divided into different groups: 10.00,5.00,1.00,0.50,0.10,0.05 and 0.01 ?mol?L-1 S1 groups,meanwhile,PC3 control group and cyclophosphamide group were set up.MTT was used to detect the inhibitory rate of PC3 cell proliferation.Flow cytometry was used to detect the inducing effect of S1 on apoptosis of PC3 cells.Caspase 3,8,9 kits were used to detect apoptosis route.Results The inhibitory rates of PC3 cells induced by 0.10-10.00 ?mol?L-1 S1 were significantly higher than that in cyclophosphamide group(P

Objective To investigate the effects of TLR4 on the radiosensitivity of tumor cells.Methods The cell lines of RAW264.7,Lewis,MFC,Hepal-6,Bl6,and NIH3T3 were irradiated with 5 Gy X-rays or sham-irradiated.24 h after irradiation,the expression of TLR4 was detected by flow cytometry.According to the TKR4 level,cells were divided into three groups:without treatment,LPS stimulation and TAK242 block.CCK-8 kit and Annexin-V Apoptosis Kit were used to detect cell proliferation,apoptosis and cell cycle distribution of each group.Results After 24 h of 5 Gy ionizing radiation,TLR4 was significantly increased in Lewis cells (t =-8.68,P ＜0.01) but decreased in MFC cells (t =25.8,P ＜ 0.01) and had no significant changes in Hepal-6,B16 and RAW264.7 cells.In addition,the proliferation vitality (t =57.62,-6.23,P ＜ 0.01) and survival fraction (t =13.37,19.24,P ＜ 0.01) of the Lewis and MFC cells were reduced especially for the TLR4-blocked cells,and the apoptosis rates of both Lewis (t=-167.85,P＜0.01) and MFC cells (t=-26.45,P＜0.01) were elevated.The percentages of G0/G1 phase and S phase Lewis cells were significant increased (t =8.68,14.89,P ＜ 0.01) but its G2/M phase were reduced (t =-37.48,P ＜ 0.01).However,the percentages of G0/G1 phase and S phase MFC cells were obviously reduced (t =20.31,4.48,P ＜ 0.01) and G2/M phase increased (t =-13.06,P ＜ 0.01).For both cell lines of Lewis and MFC,the cycle distribution of TAK242 and LPS groups didn't change significantly.Conclusions High expression TLR4 in the Lewis cells is related to cell proliferation and apoptosis but not cell cycle distribution,and hence TLR4 could influence the radiosensitivity of tumor cells.

Objective To detect the expression of DNA damage response genes induced by radiation in human peripheral blood lymphocyte,and to explore the new biomarkers of radiation.Methods The human peripheral blood cells were irradiated to X-rays at different doses of 0,1,2,3,4,and 5 Gy.The quantitative real.time qPCR wag used to detect the expressions of cyclin-dependent kinase inhibitor l a gene(Cdknl a)and growth arrest and DNA damage inducible gene(Gadd45a)in lymphoeytes at 4 and 24 h post-irradiation,respectively.The method of CB mieronucleus was used to determine the change of micronucleus ratio.Results The expression of Cdknl a in peripheral blood lymphocytes wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy.reached the peak at 4 Gy and began to decrease at 5 Gy,which showed a dose-dependent manner(r=0.946,0.975,P<0.05).Similarly,the expression of Gadd45α in human peripheral blood lymphocytes was also increased significantly at 4 and 24 h post-irradiation to 0-5 Gy in a dose-dependent manner,while the expression of Gadd45a at 4 h wag higher than that at 24 h(r=0.936,0.797,P<0.05).The ratio of micronuclei wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy(r=0.990,0.984,P<0.05).Conciusions Cdknl a and Gadd45α expression could be increaged significandy at 4 and 24 h post-irradiation to 0-5 Gy,showing a good linear relationship.which might be candidate for radiation biological dosimeter.

Objective To investigate the effects of ionizing radiation on the expression of P21 protein in Jurkat cell line and p21 gene in thymocytes and splenocytes of mice.Methods Flow cytometry (FCM)was used to analyze the expression of P21 protein in Jurkat cells at 12 and 24 h after irradiation to 0,0.5,1.0,2.0,4.0,and 6.0 Gy.Real-time PCR was used to detect the expression of p21 gene in thymocytes and splenocytes of mice at4 and 24 h after irradiation to 0,0.5,1.0,2.0,4.0,and 6.0 Gy.Multi-staining was used to analyze the micronucleus rates of Rct in bone marrow.Results The expressions of P21 protein were increased in a dose-dependent manner during 0.5-4.0 Gy(t=-24.23--3.96,P<0.05),but decreased at 6.0 Gy at 12 and 24 h post-irradiation(t=-11.19,-14.50,P<0.05).The expressions of p2 1 gene in both thymocytes and splenocytes of mice were increased in dose-dependent manner in the range of 0-6.0 Gy(including 6.0 Gy)(t=-29.96-8.80,P<0.05),and reached to the peak at 6.0 Gy at 4 and 24 h post-irradiation(t=-11.84--3.42,P<0.05),except thymocytes at 4 h and 1.0 Gy post-irradiation(t=-3.42,P>0.05).Conclusions The expressions of P21 protein and p21 gene could be increased by X-ray irradiation.which shows good dosedependent manners in certain range of dose.

0.05).The apoptotic percentage was increased significantly after X-rays irradiation with the dose of 6 Gy(P

Objective To observe the changes in expressions of spleen regulatory T cells (Tregs)and the related factor forkhead box protein-3 (Foxp3) after irradiation with different doses of X-ray in mice at different times,and to elaborate the effects of X-rays on regulatory T cells and Foxp3.Methods 112male ICR mice were randomly divided into 2 groups and irradiated by X-rays at the doses of 0.075 and 2 Gy,respectively.The mice were killed at 0,4,8,16,24,48,and 72 h post-irradiation and the spleens removed.Flow cytometry was used to detect the percentage of CD4 + CD25 + Treg and protein expression of (Foxp3),and RT-PCR was used to exmiamine the mRNA expression of Fox3.Results Compared with those before irradiation,the CD4 + CD25 + Treg positive rates began to increase and peaked at 8 h post-irradiation with 0.075 Gy at 8,16,24,72 h(t = 8.73,10.55,4.21,4.65 ,P ＜ 0.05) and 2 Gy at 8,16,48,72 h(t = 4.65,4.28,3.71,2.88,P ＜ 0.05),and then slightly decreased,but still remained at high levels.The mRNA protein levels of Fox3 did not change significantly after exposure to the dose of 0.075 Gy,but began to significantly increase at 8 h after exposure to the dose of 2 Gy.However,the Foxp3 protein level began to increase 4 h post-irradiation,peaked at 16 h,and then slightly decreased,but still ramained at high levels (t =2.59,3.37,3.70,3.20,P＜0.05).Conclusions The changes in expressions of Tregs and Foxp3 after high- and low-dose X-ray irradiation may be used to explain the differences in immune effects induced by ionizing radiation at different doses.

Objective To study the effects of whole-body irradiation(WBI)with different doses of X-rays on apoptosis in mouse splenocytes and peritoneal macrophages.Methods The apoptosis percentages of mouse splenocytes and peritoneal macrophages were detected with flow cytometry(FCM)at different time after the whole-body X-irradiation using the staining of Annexin-V and PI.Results As compared with the control,the percentage of apoptosis in mouse splenocytes began to increase gradually 24 h after WBI with 2 Gy X-rays(P

N 6-methyladenosine (m 6A) is the most abundant RNA base modification in mammals, especially in eukaryotic messenger RNA (mRNA). N 6-methyladenosine modification can regulate RNA splicing, translocation, stability and ultimately affect protein synthesis. m 6A modification is catalyzed by RNA writers, reduced by erasers and also be recognized by readers. Abnormal changes ofm 6A levels are closely related to tumor occurrence and development, including proliferation, growth, invasion and metastasis. In the process of tumor radiotherapy, m 6A modification affects the efficacy of radiotherapy by affecting DNA damage, tumor stem cell generation and tumor cell radiation sensitivity. This article reviews the role of m 6A-modified epigenetic regulation in malignant tumors and the research progress of its mechanism in tumor radiotherapy, in order to provide new ideas for the development of clinical tumor molecular targeted therapies and radiosensitizers.