Dongqing Ren

A specific miRNA signature promotes radioresistance of human cervical cancer cells

BackgroundThe mechanisms responsible for cervical cancer radioresistance are still largely unexplored. The present study aimed to identify miRNAs associated with radioresistance of cervical cancer cells.MethodsThe radioresistant cervical cancer cell variants were established by repeated selection with irradiation. The miRNA profiles of radioresistant cells and their corresponding controls were analyzed and compared using microarray. Differentially expressed miRNAs were confirmed by quantitative real-time PCR. Cervical cancer cells were transfected with miRNA-specific mimics or inhibitors. Radiosensitivity of cervical cancer cells were determined using colony-forming assay.ResultsAmong the differentially expressed miRNAs, 20 miRNAs showed the similar pattern of alteration (14 miRNAs were overexpressed whilst 6 were suppressed) in all three radioresistant cervical cancer cell variants compared to their controls. A miRNA signature consisting of 4 miRNAs (miR-630, miR-1246, miR-1290 and miR-3138) exhibited more than 5 folds of increase in radioresistant cells. Subsequent analysis revealed that these four miRNAs could be up-regulated in cervical cancer cells by radiation treatment in both time-dependent and dose-dependent manners. Ectopic expression of each of these 4 miRNAs can dramatically increase the survival fraction of irradiated cervical cancer cells. Moreover, inhibition of miR-630, one miRNA of the specific signature, could reverse radioresistance of cervical cancer cells.ConclusionsThe present study indicated that miRNA is involved in radioresistance of human cervical cancer cells and that a specific miRNA signature consisting of miR-630, miR-1246, miR-1290 and miR-3138 could promote radioresistance of cervical cancer cells.

Effect of Electromagnetic Pulses (EMP) on associative learning in mice and a preliminary study of mechanism

Abstract Purpose: To investigate the effects of electromagnetic pulses (EMP) on associative learning in mice and test a preliminary mechanism for these effects. Materials and methods: A tapered parallel plate gigahertz transverse electromagnetic (GTEM) cell with a flared rectangular coaxial transmission line was used to expose male BALB/c mice to EMP (peak-intensity 400 kV/m, rise-time 10 ns, pulse-width 350 ns, 0.5 Hz and total 200 pulses). Concurrent sham-exposed mice were used as a control. Associative learning, oxidative stress in the brain, serum chemistry and the protective action of tocopherol monoglucoside (TMG) in mice were measured, respectively. Results: (1) Twelve hour and 1 day post EMP exposure associative learning was reduced significantly compared with sham control (p < 0.05) but recovered at 2 d post EMP exposure. (2) Compared with the sham control, lipid peroxidation of brain tissue and chemiluminescence (CL) intensity increased significantly (p < 0.05), while the activity of the antioxidant enzymes Superoxide Dismutase [SOD], Glutathione [GSH], Glutathione Peroxidase [GSH-Px], Catalase [CAT]) decreased significantly (p < 0.05) at 3 h, 6 h, 12 h and 1 d post EMP exposure. All these parameters recovered at 2 d post EMP exposure. (3) No significant differences between the sham control group and EMP exposed group were observed in serum cholesterol and triglycerides. (4) Pretreatment of mice with TMG showed protective effects to EMP exposure. Conclusions: EMP exposure significantly decreased associative learning in mice and TMG acted as an effective protective agent from EMP exposure. This mechanism could involve an increase of oxidative stress in brain by EMP exposure.

Electromagnetic pulses induce fluctuations in blood pressure in rats

Purpose: To investigate the effects of exposure to electromagnetic pulses (EMP) on functional indices of the cardiovascular system in male Sprague-Dawley rats. Materials and methods: A tapered parallel plate Gigahertz Transverse Electromagnetic cell (GTEM cell) with a flared rectangular coaxial transmission line was used to expose the rats to EMP (0.5 pps, total 200 pulses and whole-body averaged specific absorption rate 50 mW/kg at 200 kV/m or 75 mW/kg at 400 kV/m). Concurrent sham-exposed animals were used as controls. Cardiovascular functions, namely, heart rate, and systolic, mean and diastolic blood pressures were measured immediately and up to 4 weeks post-exposure using a non-invasive tail-cuff photoelectric sensor sphygmomanometer. Results: The heart rates in sham- and EMP-exposed rats were not significantly changed. In the exposed rats, increased systolic blood pressure (SBP) occurred at 0 h and decreased SBP occurred at 1 day and 3 days after exposure. Significantly higher diastolic blood pressure (DBP) was found at 0 h and significantly lower DBP was found at 12 h, 1 day, and 1 month after exposure. Significantly higher mean arterial pressure (MAP) was noted at 0 h and significantly lower MAP was noted at 1 day. Conclusions: Significant alterations in arterial blood pressure were observed in rats exposed to EMP exposure while heart rate was not altered.

Effects of PEMF exposure at different pulses on osteogenesis of MC3T3-E1 cells

OBJECTIVE Pulsed electromagnetic fields (PEMFs) were considered to be a factor which may affect osteogenesis of osteoblasts, but the effects were diverse with different PEMF parameters. The aim of the current study is to explore the effects of exposure to PEMFs at different pulse number on osteogenesis of osteoblasts. DESIGN The mouse osteoblast-like MC3T3-E1 cells were exposed to 0, 400 or 2800 pulses 400kV/m PEMF and the proliferation, differentiation and mineralization of cells were observed after PEMF exposure by the methods of MTT, biochemical measurement, real-time PCR and Alizarin Red assay. RESULTS Compared with 0 pulses groups, the growth curve, alkaline phosphatase (ALP) activity, mRNA level of osteocalcin (OCN) and mineralized nodule formation of MC3T3-E1 cells did not change after 400 pulses PEMF exposure, but decreased after 2800 pulses PEMF exposure. It suggested that under our experimental conditions, only 2800 pulses 400kV/m PEMF exposure can suppress the proliferation, differentiation and mineralization of MC3T3-E1 cells, but 400 pulses 400kV/m PEMF exposure cannot. CONCLUSIONS Pulse number is another involved parameter which may influence the effects of PEMF on osteogenesis of osteoblasts.

Effect of EMP on Superoxide Dismutase and Malondialdehyde in K562 cells

AIM To observe effect of EMP on the kinetic equilibrium of produce and elimination of free radicals. METHODS Human erythroleukemia K562 cells were exposed or shamly exposed to EMP before the activity of SOD and the contents of MDA were measured using NBT and TBA methods respectively. RESULTS The activity of SOD decreased 12h after 200kV·m−1EMP exposure, the contents of MDA increased 24h after 200kV·m−1 EMP exposure. The contents of MDA increased and the activity of SOD decreased at 12h and 24h after 400kV·m−1EMP exposure. CONCLUSION Excessive free radicals produced from impact of EMP on the kinetic equilibrium of produce and elimination of free radicals maybe a way through which EMP exposure inducing cell damage.

A novel strategy to tag MMPs-positive cells for in vivo imaging of tumor cells

Matrix metalloproteinases (MMPs) are endopeptidases responsible for degrading the extracellular matrix (ECM) and remodeling tissue in both physiological and pathological processes. MMP2 and membrane-type 1 MMP (MT1-MMP) have been associated with tumor invasion, metastasis and angiogenesis; therefore, a molecular imaging strategy assessing their activity may help to predict the malignancy of tumors. Here, we established a novel method of specifically tagging the surface of MMP2- and MT1-MMP-positive cells, and applied it to the development of an optical imaging probe. We constructed a protein-based probe. In vitro and in vivo experiments demonstrated that the probe was cleaved and specifically remained in tumor xenografts in a MMP-dependent manner.

Effects of EMP irradiation on production of IL-2 in spleen cells of mice

AIM To investigate the bioeffects of EMP irradiation on the mouse immune system. METHODS EMP irradiation (field intensity: 57kV/m, 300000 pulses, at free posture), Concentration of IL-2 in supematants of mouse spleen cells in groups of control and EMP irradiation was examined by ELISA. RESULTS Concentration of lL- 2 was 50.7±24.7 (P = 0.285), 169.6±63.9 (P≪ 0.01), 52.2±12.4 (P = 0.319), 263.9±31.5(P≪0.01) and 85.9±24.3 (pg/ml) in groups of6h, 24h, 48h, 96h after EMP irradiation and control respectively. IL-2 concentration in groups of 24h and 96h after EMP irradiation significantly increased (2 times and 3 times of control group respectively, P≪0.01). While compared with that of control group, IL-2 concentration in groups of 6h and 48h after EMP irradiation decreased (about 40 percent, P≪0.05). In phases, IL-2 concentration went down and up, then down and up again, just like a Cosine wave. CONCLUSION Results demonstrate that the production of IL-2 in spleen cells of mice fluctuates at different time after EMP irradiation under our experimental conditions.

Effects of EMP on bonding ability of insulin and its receptor

AIM To discuss the effects of EMP on bonding ability of insulin and itpsilas receptor. METHODS HL-7702[L-02]GNHu6 cells (5times105 ldr mL-1) were divided into 2 groups: anti-insulin-fluorescent labeling group (including cell-irrad + insulin-irrad group, cell-irrad + normal insulin group, normal cell + insulin-irrad group, normal cell + normal insulin group, total 4 sub-groups) and anti-insulin receptor-fluorescent labeling group (including cell-irrad group, normal cell group, total 2 sub-groups). Some 0.5 mgmiddotmL-1 insulin solution and the groups which need to be irradiated were irradiated by 400 kVmiddotm-1 EMP. After the irradiation, the indirect immuno fluorescent experiment was done, immediately. And then, all the samples were detected by FCM. After EMPpsilas irradiation, the percentage of the L-02 cells which were fluorescent-labelled by FITC on cell membranepsilas insulin receptor increased. After EMPpsilas irradiation, the percentage of the L-02 cells which were fluorescent-labelled by FITC on cell membranepsilas insulin increased than un-irradiated, no matter whether the insulin which was put into the L-02 cells was irradiated or not. Compared with the un-irradiated insulin, no matter the irradiated insulin was put into un-irradiated or irradiated L-02 cells, the percentage of the L-02 cells which were fluorescent-labelled by FITC on cell membranepsilas insulin decreased. CONCLUSION 400 k V ldr m-1 EMP irradiation may probably change insulinpsilas spatial structure, decrease the bonding ability between insulin and its receptor, and show some excitatory effect on L-02 cells.