ABSTRACT
The present study investigated the enhanced radiosensitivity of U-251 cells induced by sodium butyrate (NaB) and its possible mechanisms. Increased radiosensitivity of U251 cells was examined by clonogenic cell survival assays. The expression of Ku70 mRNA and protein was detected by using RT-PCR and Western blotting respectively. γ-H2AX foci were measured at different time points after ionizing irradiation alone or combined with NaB treatment. The results showed that cell survival rate was significantly reduced, both D0 and Dq values were decreased (D0: 1.43 Gy vs. 1.76 Gy; Dq: 1.22 Gy vs. 2.05 Gy) after the combined treatment as compared with irradiation alone, and sensitivity enhancing ratio (SER) reached 1.23. The average number of γ-H2AX foci per cell receiving the combined treatment was significantly increased at different time points, and the expression levels of Ku70 mRNA and protein were suppressed by NaB in a dose-dependent manner. It was concluded that enhanced radiosensitivity induced by NaB involves an inhibited expression of Ku70 and an increase in γ-H2AX foci, which suggests decreased ability in DSB repair.
ABSTRACT
Recent researches show that follicle stimulating hormone (FSH) plays an important regulatory role in the angiogenesis of ovarian cancer by influencing the level of some factors such as hypoxia inducefactor-1 ( HIF-1 ) ,vascular endothelial growth factor (VEGF). Meanwhile, recent studies report that FSH and FSH receptor(FSHR) may also participate in the angiogenesis of other solid tumors like lung cancer. FSH is closely related to the tumor angiogenesis, which provides a novel therapeutic target for anti-angiogenesis thera-py.
ABSTRACT
Hepatitis B virus (HBV)-induced hepatocellular carcinoma (HCC) is one of the most frequently occurring cancers. Hepadnaviral DNA integrations are considered to be essential agents which can promote the process of the hepatocarcinogenesis. More and more researches were designed to find the relationship of the two. In this study, we investigated whether HBV DNA integration occurred at sites of DNA double-strand breaks (DSBs), one of the most detrimental DNA damage. An 18-bp I-SceI homing endonuclease recognition site was introduced into the DNA of HepG2 cell line by stable DNA transfection, then cells were incubated in patients' serum with high HBV DNA copies and at the same time, DSBs were induced by transient expression of I-SceI after transfection of an I-SceI expression vector. By using nest PCR, the viral DNA was detected at the sites of the break. It appeared that integration occurred between part of HBV x gene and the I-SceI induced breaks. The results suggested that DSBs, as the DNA damages, may serve as potential targets for hepadnaviral DNA insertion and the integrants would lead to widespread host genome changes necessarily. It provided a new site to investigate the integration.
ABSTRACT
Objective To explore the inhibitory effects of Corilagin on the production of proinflammatory cytokines in microglia induced by radiation. Methods The cytotoxicity of Corilagin was measured by MTT assay. Microglia BV-2 cells were irradiated 0 or 32 Gy after pretreated with Corilagin for 12 hours. Realtime-PCR was used to detect the mRNA levels of inflammatory cytokines, such as IL-1β,TNF-α on several time-points. The content of nitric oxide (NO) was determined with nitrate reductase method. The translocation of NF-κB was measured by Western blot and immunocytochemical stain.Confocal microscopy was used to observe the expression of Iba-1 and Nemo. Results No cytotoxicity was detected on BV-2 cells with 1-10 μg/ml Corilagin. Iba-1 expression in microglia cells was activated by irradiation, the expression levels of inflammatory cytokines, such as IL-1β, TNF-α and NO were also elevated. Whereas, the production of IL-1 β, TNF-α in activated microglia cells was significantly inhibited with 5 μg/mL corilagin ( tIL-1β = 6. 341, tTNF-α = 3.41 1, tNO = 3. 134, P ＜ 0. 05 ). Corilagin significantly inhibited the expression of Nemo and the translocation of NF-κB p65. Conclusion Corilagin could inhibit the activation of irradiated microglia cells and down-regulate the expression of inflammatory cytokines, via inhibition of the NF-κB signaling pathway.
ABSTRACT
The effects of PEG10 on hydrogen peroxide (H(2)O(2))-induced apoptosis in human normal liver cell line L0(2) were investigated. The PEG10 gene was transfected into L0(2) cells by lipofectamine, the positive clone was screened by G418 and defined as L0(2)/PEG10, while the cell transfected with empty expression vector (pEGFP-N1) was defined as L0(2)/vector. L0(2)/vector and parental L0(2) cells served as control. RT-PCR and Western blotting were employed to detect the expression of target genes. H(2)O(2) (50-400 mmol/L) was administered to induce the apoptosis of L0(2) cells. Cells viability was measured by MTT and the morphological changes of apoptotic cells were determined by fluorescence microscopy using hoechst33342 nuclei staining. DNA fragmentation was observed by agarose gel electrophoresis. PEG10 mRNA and protein levels in L0(2)/PEG10 cells were significantly increased as compared with those in the control cells. After treatment with 400 mmol/L H(2)O(2) for 24 h, the cellular growth inhibition rate of L0(2)/PEG10 cells was significantly lower (58.2%) than that of L0(2) (92.5%) and L0(2)/vector (88%). Distinct morphological changes characteristic of cell apoptosis such as karyopyknosis and conglomeration were not observed in L0(2)/PEG10. Ladder-like DNA fragmentation in a dose-dependent manner was observed in both L0(2) and L0(2)/vector cell lines, but not in L0(2)/PEG10. PEG10 over-expression significantly inhibited cytotoxicity induced by H2O2 on human normal liver cell line L0(2) by antagonizing H(2)O(2)-induced apoptosis.
ABSTRACT
The relationship between Ala/Ser polymorphism in 133 codon of exon 3 region of the RASSF1 gene and genetic susceptibility of lung cancer in Hubei province Han population was investigated by a case-control study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was adopted to analyze the polymorphism of codon 133 of exon 3 in the RASSF1 gene of 100 pathologically diagnosed lung cancer patients, and 100 healthy controls. The relationship between different genotypes and the susceptibility of lung cancer was analyzed. Among 200 blood samples from Han people in Hubei Province, including 100 from lung cancer patients and 100 from healthy controls, the frequencies of Ala/Ala, Ala/Ser, Ser/Ser genotype of the RASSF1 in lung cancer patients were 83%, 16%, 1%, and those in healthy controls was 93%, 7%, 0% respectively, with the difference being statistically significant between two groups (P<0.05). The individuals with Ala/Ser genotype had higher risk of suffering from lung cancer, with an OR of 2.341, and 95% CI of 1.009-6.393 respectively. It was concluded that RASSF1Ala133Ser was a susceptible genetic factor of lung cancer. Ala/Ser genotype increased the risk of lung cancer.
ABSTRACT
To investigate the RNA interference (RNAi) effect induced by vector-derived small interfering RNA (siRNA) targeting the three gatekeeper genes (Rad52, Ku70, Ku80) and screen the more effective target sites from candidates for further research, by using siRNA design tools online, we selected 2 candidate sequences directed to every gatekeeper gene. According to the sequences, six vector-derived siRNAs (denoted psiRNA1-6) and one mocking psiRNA7 were constructed. Among them, psiRNA1 and psiRNA2 targeted Rad52, psiRNA3 and psiRNA4 to Ku70, psiRNA5 and psiRNA6 to Ku80. The mocking psiRNA7 was used as control. After sequence identification, the seven plasmids were transfected into HepG2 cell line. siRNA-induced silencing of gatekeeper genes was determined by using RT-PCR at RNA level and Western Blot at protein level. The results showed that the six plasmids specifically targeting the coding region of gatekeeper genes were successfully designed and constructed. To some extent, the six plasmids could reduce the expression of target gene. Comparatively, the plasmid-derived siRNA psiRNA1, psiRNA4 and psiRNA5 were more effective than their counterparts. The results suggest that the gene silencing efficiency of siRNA is different, depending on their targeted region, and siRNA may provide us with practical tools for further study on the three gatekeeper genes, i.e. Rad52, Ku70, Ku80.
ABSTRACT
To investigate the RNA interference (RNAi) effect induced by vector-derived small interfering RNA (siRNA) targeting the three gatekeeper genes (Rad52, Ku70, Ku80) and screen the more effective target sites from candidates for further research, by using siRNA design tools online,we selected 2 candidate sequences directed to every gatekeeper gene. According to the sequences, six vector-derived siRNAs (denoted psiRNA1-6) and one mocking psiRNA7 were constructed. Among them, psiRNA1 and psiRNA2 targeted Rad52, psiRNA3 and psiRNA4 to Ku70, psiRNA5 and psiRNA6 to Ku80. The mocking psiRNA7 was used as control. After sequence identification, the seven plasmids were transfected into HepG2 cell line. siRNA-induced silencing of gatekeeper genes was determined by using RT-PCR at RNA level and Western Blot at protein level. The results showed that the six plasmids specifically targeting the coding region of gatekeeper genes were successfully designed and constructed. To some extent, the six plasmids could reduce the expression of target gene.Comparatively, the plasmid-derived siRNA psiRNA1, psiRNA4 and psiRNA5 were more effective than their counterparts. The results suggest that the gene silencing efficiency of siRNA is different,depending on their targeted region, and siRNA may provide us with practical tools for further study on the three gatekeeper genes, i.e. Rad52, Ku70, Ku80.