OBJECTIVETo investigate the changes of gene expression in rat neuron induced by 1.8 GHz radiofrequency electromagnetic fields (RF EMF) to screen for RF EMF-responsive genes and the effect of different exposure times and modes on the gene expression in neuron.

METHODSTotal RNA was extracted immediately and purified from the primary culture of neurons after intermittent exposed or sham-exposed to a frequency of 1.8 GHz RF EMF for 24 hours at an average special absorption rate (SAR) of 2 W/kg. Affymetrix Rat Neurobiology U34 array was applied to investigate the changes of gene expression in rat neuron. Differentially expressed genes (Egr-1, Mbp and Plp) were further confirmed by semi-quantitative revere transcription polymerase chain reaction (RT PCR). The expression levels of Egr-1, Mbp and Plp were observed at different exposure times (6, 24 h) and modes (intermittent and continuous exposure).

RESULTSAmong 1200 candidate genes, 24 up-regulated and 10 down-regulated genes were found by using Affymetrix microarray suite software 5.0 which are associated with multiple cellular functions (cytoskeleton, signal transduction pathway, metabolism, etc.) after functional classification. Under 24 h and 6 h intermittent exposure, Egr-1 and Plp in experiment groups showed statistic significance (P < 0.05) compared with the control groups, while expression of Mbp did not change significantly (P > 0.05). After 24 h continuous exposure, Egr-1 and Mbp in experiment groups showed statistic significance (P < 0.05) compared with the control group, while expression of Plp did not change significantly (P > 0.05). Under the same exposure mode 6 h, expression of all the 3 genes did not change significantly. Different times (6, 24 h) and modes (intermittent and continuous exposure) of exposure exerted remarkable different influences on the expression of Egr-1, Mbp, Plp genes (P < 0.01).

CONCLUSIONThe changes of many genes transcription were involved in the effect of 1.8 GHz RF EMF on rat neurons; Down-regulation of Egr-1 and up-regulation of Mbp, Plp indicated the negative effects of RF EMF on neurons; The effect of RF intermittent exposure on gene expression was more obvious than that of continuous exposure; The effect of 24 h RF exposure (both intermittent and continuous) on gene expression was more obvious than that of 6 h (both intermittent and continuous).

Animals ; Cells, Cultured ; Dose-Response Relationship, Radiation ; Down-Regulation ; radiation effects ; Electromagnetic Fields ; Neurons ; metabolism ; radiation effects ; Rats ; Up-Regulation ; radiation effects

The aim of the present study is to analyze the global research trend of radiation-responsive genes and identify the highly reproducible radiation-responsive genes. Bibliometric methods were applied to analyze the global research trend of radiation-responsive genes. We found 79 publications on radiation-responsive genes from 2000 to 2017. A total of 35 highly reproducible radiation-responsive genes were identified. Most genes are involved in response to DNA damage, cell proliferation, cell cycle regulation, and DNA repair. The p53 signal pathway was the top enriched pathway. The expression levels of 18 genes in human B lymphoblastoid cell line (AHH-1) cells were significantly up-regulated in a dose-dependent manner at 24 h after exposure to 0-5 Gy 60Co γ-ray irradiation. Our results indicate that developing a gene expression panel with the 35 high reproducibility radiation-responsive genes may be necessary for qualitative and quantitative assessment after exposure.
Dose-Response Relationship, Radiation ; Gene Expression Profiling ; Gene Expression Regulation ; radiation effects ; Humans ; Radiometry ; methods ; Reproducibility of Results ; Up-Regulation ; radiation effects

OBJECTIVE: To study the effect of microwave radiation on the levels of malondialdehyde (MDIA) and activity of superoxide dismutase (SOD) of Nasopharyngeal carcinoma cells. METHOD: The experiment were divided into four groups included control, 10, 20 and 30 mW/cm2 groups. The methods, such as TBA colorimetric assay and modified NBT hydroxylamine method, were used to detect the effect of microwave radiation on the levels of MDA and activity of SOD of nasopharyngeal carcinoma cells. RESULT: With increase of microwave radiation, TBA assay showed that the levels of MAD were 1.4 and 3.5 times in 20 mW/cm2 group and 30 mW/cm2 group respectively compared with control group, there were significant differences among them (P < 0.05). NBT method shows that the activity of SOD were 68.2%, 46.2% and 36.0% of 10, 20 and 30 mW/cm2 groups respectively compared with control group, there were significant differences among them too (P < 0.01). CONCLUSION Microwave Radiation could up-regulate the levels of MAD) while down-regulate the SOD activity.
Cell Line, Tumor ; Dose-Response Relationship, Radiation ; Gene Expression Regulation, Neoplastic ; Humans ; Malondialdehyde ; metabolism ; radiation effects ; Microwaves ; Nasopharyngeal Neoplasms ; metabolism ; Superoxide Dismutase ; metabolism ; radiation effects ; Up-Regulation

BACKGROUND AND OBJECTIVEThe mRNA levels of 59 genes, detected by cDNA microarray, were up-regulated in the radioresistant human esophageal cacinoma cell line TE13R120 as compared with its parental cell line TE13 before and after radiation, and the expression of NRAGE gene showed a gradually up-regulating tendency. This study aimed to further detect the differences of NRAGE gene and protein expression and apoptosis between TE13R120 and TE13 cells, and to investigate the relationship between the NRAGE and the radioresistance of TE13R120 cells and its mechanism.

METHODSThe two cell lines were irradiated by ⁶⁰Co γ-ray at different conditions. Reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry were used to detect the expression of NRAGE. Flow cytometry (FCM) was used to detect the cell apoptosis before and after irradiation.

RESULTSThe mRNA level of NRAGE was higher in TE13R120 cells than in TE13 cells before and after irradiation (before radiation: 0.25 ± 0.03 vs. 0.49 ± 0.03; 4 Gy 4 h: 0.31 ± 0.03 vs. 0.53 ± 0.02; 4 Gy 16 h: 0.32 ± 0.04 vs. 0.59 ± 0.04; 4 Gy 24 h: 0.36 ± 0.05 vs. 0.72 ± 0.04; 2 Gy 12 h: 0.32 ± 0.02 vs. 0.64 ± 0.04; 6 Gy 12 h: 0.36 ± 0.02 vs. 0.79 ± 0.05; 10 Gy 12 h: 0.46 ± 0.04 vs. 0.85 ± 0.01; P < 0.01), and the mRNA level of NRAGE was increased gradually with the increase of radiation dose and time in the two cell lines (P < 0.05 and P < 0.01). Western blot results showed no difference of NRAGE protein level in cytoplasm between TE13R120 cells and TE13 cells before and after irradiation, but its level in nuclei was higher in TE13R120 cells than in TE13 cells at different radiation time and dosages. Immunocytochemistry showed similar results as Western blot. FCM showed no significant difference in apoptosis rate between TE13R120 and TE13 cells before and after radiation.

CONCLUSIONNRAGE may play an important role in the radiation responses of the two cell lines, and may participate in the formation of radioresistance of TE13R120 cells by changing its subcellular localization, but its relationship with cell apoptosis has not been confirmed.

Antigens, Neoplasm ; genetics ; metabolism ; radiation effects ; Apoptosis ; radiation effects ; Cell Line, Tumor ; radiation effects ; Cobalt Radioisotopes ; Esophageal Neoplasms ; metabolism ; pathology ; Humans ; Neoplasm Proteins ; genetics ; metabolism ; radiation effects ; RNA, Messenger ; metabolism ; radiation effects ; Radiation Tolerance ; Radiotherapy Dosage ; Time Factors ; Up-Regulation

OBJECTIVETo explore the role of p21 in ionizing radiation-induced changes in protein levels during the G2/M transition and long-term G2 arrest.

METHODSProtein expression levels were assessed by western blot in the human uveal melanoma 92-1 cells after treatment with ionizing radiation. Depletion of p21 was carried out by employing the siRNA technique. Cell cycle distribution was determined by flow cytometry combined with histone H3 phosphorylation at Ser28, an M-phase marker. Senescence was assessed by senescence- associated-β-galactosidase (SA-β-gal) staining combined with Ki67 staining, a cell proliferation marker.

RESULTSAccompanying increased p21, the protein levels of G2/M transition genes declined significantly in 92-1 cells irradiated with 5 Gy of X-rays. Furthermore, these irradiated cells were blocked at the G2 phase followed by cellular senescence. Depletion of p21 rescued radiation-induced G2 arrest as demonstrated by the upregulation of G2/M transition kinases, as well as the high expression of histone H3 phosphorylated at Ser28. Knockdown of p21 resulted in entry into mitosis of irradiated 92-1 cells. However, cells with serious DNA damage failed to undergo cytokinesis, leading to the accumulation of multinucleated cells.

CONCLUSIONOur results indicated that p21 was responsible for the downregulation of G2/M transition regulatory proteins and the bypass of mitosis induced by irradiation. Downregulation of p21 by siRNA resulted in G2-arrested cells entering into mitosis with serious DNA damage. This is the first report on elucidating the role of p21 in the bypass of mitosis.

Cell Cycle Checkpoints ; radiation effects ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; DNA Damage ; Down-Regulation ; Fibroblasts ; metabolism ; radiation effects ; Gene Expression Regulation ; radiation effects ; Humans ; Mitosis ; radiation effects ; RNA Interference ; RNA, Small Interfering ; Radiation, Ionizing ; Up-Regulation

OBJECTIVETo investigate the changes of gene expression in rat neurons induced by 1.8 GHz radiofrequency electromagnetic fields (RF EMF) and to screen for the RF EMF-responsive genes.

METHODSNewly-born SD rats in 24 hours were sacrificed to obtain cortex and hippocampus neurons. The cells were divided randomly into two groups: the experiment group (the irradiation group) and the control group (the false irradiation group). In the irradiation group, after twelve days' culture, neurons were exposed to 1.8 GHz RF EMF modulated by 217 Hz at a specific absorption rate (SAR) of 2 W/kg for 24 hours (5 minutes on/10 minutes off) while in the false control group, the neurons were put in the same waveguide as in the irradiation group, but were not exposed to any irradiation. The total RNA was isolated and purified immediately after exposure. The affymetrix rat neurobiology U34 assay was used for detecting the changes in gene expression profile according to the manufacturer's instruction. RF EMF-responsive candidate gene was confirmed by using ribonuclease protection assay (RPA).

RESULTSAmong 1200 candidate genes, the expression levels of 34 genes were up or down regulated. Microtubule associated protein 2 (Map2) gene was selected as the candidate and subjected to further analysis. RPA data clearly revealed that Map2 was statistically significantly up-regulated after neurons were exposed to the RF EMF (P < 0.05).

CONCLUSIONThe modulation of gene expression and function of Map2 as a neuron specific cytoskeleton protein is crucial to maintain the normal framework and function of neurons. The finding that 1.8 GHz RF EMF exposure increases the expression of Map2 might indicate some unknown effects of RF EMF on neurons.

Animals ; Animals, Newborn ; Cell Phone ; Cells, Cultured ; Dose-Response Relationship, Radiation ; Down-Regulation ; Electromagnetic Fields ; Female ; Gene Expression ; radiation effects ; Male ; Microtubule-Associated Proteins ; biosynthesis ; genetics ; Neurons ; metabolism ; radiation effects ; Radio Waves ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Up-Regulation

The expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF)2 in the irradiated brain was examined to test how a single high dose radiation, similar to that used for intraoperative radiation therapy given to the normal cerebrum, can affect the vascular endothelium. After a burr hole trephination in the rat skull, the cerebral hemisphere was exposed to a single 10 Gy dose of gamma rays, and the radiation effect was assessed at 1, 2, 4, 6, and 8 weeks after irradiation. His-tological changes, such as reactive gliosis, inflammation, vascular proliferation and necrosis, were correlated with the duration after irradiation. Significant VEGF and FGF2 expression in the 2- and 8-week were detected by enzyme-linked immunosorbent assay quantification in the radiation group. Immunohistochemical study for VEGF was done and the number of positive cells gradually increased over time, compared with the sham operation group. In conclusion, the radiation injuries consisted of radiation necrosis associated with the expression of VEGF and FGF2. These findings indicate that VEGF and FGF2 may play a role in the radiation injuries after intraoperative single high-dose irradiation.
Animals ; Brain/metabolism/pathology/radiation effects ; Brain Injuries/etiology/*metabolism/*pathology ; Fibroblast Growth Factor 2/*metabolism ; Necrosis ; Radiation Injuries/*pathology ; Radiosurgery/*adverse effects ; Rats ; Rats, Sprague-Dawley ; Up-Regulation/radiation effects ; Vascular Endothelial Growth Factor A/*metabolism

OBJECTIVETo investigate the effect of knocking-down microRNA-221 (miR-221) expression on the radiosensitivity of human colorectal carcinoma cells.

METHODSHuman colorectal carcinoma-derived cell line Caco2 was transfected with miR-221 antisense oligonucleotides (anti-miR-221) via Lipofectamine 2000. Real-time quantitative PCR was performed to detect the expression of miR-221 and PTEN mRNA in Caco2 cells. The changes in the protein expression of PTEN in the transfected cells were detected by Western blotting. The cell death after transfection and irradiation was detected by flow cytometry.

RESULTSTransfection with anti-miR-221 caused a significant reduction in miR-221 expression (P<0.05) and up-regulated PTEN protein expression (P<0.05) in Caco2 cells. The percentage of cell death was significantly increased in anti-miR-221 group and anti-miR-221 with irradiation group (P<0.01). Anti-miR-221 significantly enhanced the radiosensitivity of Caco2 cells, which was partially reversed by PTEN-siRNA.

CONCLUSIONAnti-miR-221 can enhance the radiosensitivity of colorectal carcinoma cells by up-regulating the expression of PTEN.

Caco-2 Cells ; radiation effects ; Colorectal Neoplasms ; genetics ; metabolism ; Humans ; MicroRNAs ; genetics ; metabolism ; PTEN Phosphohydrolase ; metabolism ; RNA, Messenger ; genetics ; Radiation Tolerance ; Transfection ; Up-Regulation

To evaluate radiosensitivity and the effects of radiation on the expression of vascular endothelial growth factor (VEGF) and VEGF receptors in the canine oral melanoma cell line, TLM 1, cells were irradiated with doses of 0, 2, 4, 6, 8 and 10 Gray (Gy). Survival rates were then determined by a MTT assay, while vascular endothelial growth factor receptor (VEGFR)-1 and -2 expression was measured by flow cytometry and apoptotic cell death rates were investigated using an Annexin assay. Additionally, a commercially available canine VEGF ELISA kit was used to measure VEGF. Radiosensitivity was detected in TLM 1 cells, and mitotic and apoptotic cell death was found to occur in a radiation dose dependent manner. VEGF was secreted constitutively and significant up-regulation was observed in the 8 and 10 Gy irradiated cells. In addition, a minor portion of TLM 1 cells expressed vascular endothelial growth factor receptor (VEGFR)-1 intracellularly. VEGFR-2 was detected in the cytoplasm and was down-regulated following radiation with increasing dosages. In TLM 1 cells, apoptosis plays an important role in radiation induced cell death. It has also been suggested that the significantly higher VEGF production in the 8 and 10 Gy group could lead to tumour resistance.
Animals ; Apoptosis/*radiation effects ; Cell Line, Tumor/radiation effects ; Dogs ; Dose-Response Relationship, Radiation ; Enzyme-Linked Immunosorbent Assay/veterinary ; Melanoma/genetics/metabolism ; Mouth Neoplasms/genetics/metabolism ; Radiation Tolerance ; Tetrazolium Salts/metabolism ; Thiazoles/metabolism ; Up-Regulation/*radiation effects ; Vascular Endothelial Growth Factor A/genetics/metabolism/*radiation effects ; Vascular Endothelial Growth Factor Receptor-1/genetics/metabolism/*radiation effects ; Vascular Endothelial Growth Factor Receptor-2/genetics/metabolism/*radiation effects

OBJECTIVETo study the radiation-sensitizing effect of up-regulating p27(kip1) expression by knocking down miR-221/222 in the U251 human glioblastoma cell line.

METHODSBy bioinformatic analysis, we searched the miRNA-221/222 sequence and found the relationship between p27(kip1) and miRNA-221/222. miRNA-221/222 antisense oligonucleotides were transfected into U251 human glioblastoma cells. Northern blot analysis was conducted to detect the expression of miR-221/222 in control, scrambled oligonucleotide (ODN) transfected and anti-mi-221/222ODNs transfected cell groups. The cell cycle kinetics was detected by flow cytometry. Clonogenic assay was used to measure the mitotic cell death and p27(kip1) expression was examined by Western blot analysis.

RESULTSBased on bioinformatic analysis, we found that the seed sequences of miR-221 and miR-222 coincide with each other, and p27(kip1) is a target for miRNA-221/222. The expression level of miR-221/222 was significantly knocked down in cells transfected with antimiR-221/222 as compared to the parental cells or cells transfected with scrambled ODN. Cell cycle was arrested in G0 or G1 phase in the anti-miR-221/222 group. When combined with irradiation, S phase fraction in the anti-miR-221/222 cell group is lower than that in the other two control groups. Anti-miR-221/222 combined with irradiation could synergistically enhance mitotic cell death. The expression of p27(kip1) was up regulated in the anti-miR-221/222 group revealed by Western blot analysis.

CONCLUSIONAnti-miR-221/222 may enhance the radiosensitivity of U251 human glioblastoma through upregulation of p27(kip1).

Base Sequence ; Cell Cycle ; radiation effects ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p27 ; genetics ; metabolism ; Glioblastoma ; genetics ; metabolism ; Humans ; MicroRNAs ; genetics ; metabolism ; Molecular Sequence Data ; Oligonucleotides, Antisense ; genetics ; metabolism ; Radiation Tolerance ; Sequence Alignment ; Up-Regulation ; radiation effects ; X-Rays