Effect of Functional Inhibition of BACE1 on Sensitization to γ-Irradiation in Cancer Cells.

Developing strategies for the radiosensitization of cancer cells by the inhibition of genes, which harbor low toxicity to normal cells, will be useful for improving cancer radiotherapy. Here, we focused on a ß-site of amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1; ß-secretase, memapsin-2). By functional inhibition of this peptidase by siRNA, it has also recently been shown that the DNA strand break marker, γH2AX foci, increased, suggesting its involvement in DNA damage response. To investigate this possibility, we knocked down BACE1 with siRNA in cancer cell lines, and sensitization to γ-irradiation was examined by a colony formation assay, γH2AX foci and level analysis, and flow cytometry. BACE1 knockdown resulted in the sensitization of HeLa, MDA-MB-231, U2OS, and SAOS cells to γ-irradiation in a diverse range. BACE1 knockdown showed a weak radiosensitization effect in osteosarcoma U2OS cells, which has a normal p53 function. HeLa and SAOS cells, which harbor p53 dysfunction, exhibited a greater level of radiosensitization. These results suggest that BACE1 may be a potential target for the radiosensitization in particular cancer cells.

Enhanced removal of I- on hierarchically structured layered double hydroxides by in suit growth of Cu/Cu2O.

To further improve the removal ability of layered double hydroxide (LDH) for iodide (I-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on its surface, forming Cu/Cu2O-LDH, which was characterized and applied as an adsorbent. Results displayed high I- saturation uptake capability (137.8 mg/g) of Cu/Cu2O-LDH compared with Cu5Mg10Al5-LDH (26.4 mg/g) even thermal activated LDH (76.1 mg/g). Thermodynamic analysis showed that the reaction between I- anions and Cu/Cu2O-LDH is a spontaneous and exothermic. Uptake kinetics analysis exhibited that adsorption equilibrium can be reached after 265 min. Additionally, the adsorbent showed satisfactory selectivity in the presence of competitive anions (e.g., SO42-), and could achieve good adsorption performance in a wide pH range of 3-8. A cooperative adsorption mechanism was proposed on the basis of the following two aspects: (1) ion exchange between iodide and interlayer anions; (2) the adsorption performance of Cu, Cu(II) and Cu2O for I-. Meanwhile, the difference between the adsorption mechanism of Cu/Cu2O-LDH, Cu5Mg10Al5-LDH and Cu5Mg10Al5-CLDH adsorbents was also elaborated and verified.

MiR-103a-3p Contributes to the Progression of Colorectal Cancer by Regulating GREM2 Expression.

PURPOSE: Our research aimed to investigate the influence of miR-103a-3p on the growth and apoptosis of colorectal cancer (CRC) cells. MATERIALS AND METHODS: Bioinformatics was employed to analyze differentially expressed microRNAs and predict target genes. qRT-PCR was applied to detect the expression of miR-103a-3p in CRC and normal cells. HCT116 and Caco-2 were chosen, and miR-103a-3p mimics, miR-103a-3p inhibitor, as well as specific siRNAs targeting GREM2, were constructed. We subsequently evaluated alternations in cell proliferation, cell cycle and cell cycle regulators, apoptosis, and related proteins (Bcl-2 and Bax) by CCK-8 testing, Western blotting, luciferase reporter, colony formation, and Annexin V-FITC/PI. Possible binding sites for miR-103a-3p on the 3'UTR of GREM2 were checked with luciferase assay, and the impact of GREM2 on miR-103a-3p activity was also validated with above biological function testing. Additionally, the effect of miR-103a-3p knockdown in CRC cells and the molecular mechanism of miR-103a-3p targeting GREM2 were also studied. RESULTS: Bioinformatics analysis revealed that miR-103a-3p expression increased remarkably in CRC, and targeted regulatory correlation existed between miR-103a-3p and GREM2. MiR-103a-3p inhibitor significantly impeded proliferative capacity and caused cell cycle arrest, as well as apoptosis, in HCT116 and Caco-2 cells. Consistent with this finding, overexpression of GREM2 showed similar effects to miR-103a-3p inhibition. Moreover, we demonstrated that miR-103a-3p connected target GREM2 and GREM2 knockdown reversed the effects of miR-103a-3p inhibitor on HCT116 and Caco-2 cell proliferation, cell cycle, and apoptosis. Further study showed that miR-103a-3p targeting GREM2 appeared to affect CRC progression via the transforming growth factor-ß pathway. CONCLUSION: MiR-103a-3p could augment CRC progression by targeting GREM2 and that miR-103a-3p/GREM2 could be potential novel targets for CRC therapy.

[Protective effect of low-dose hydrocortisone on myocardium in early septic shock].

OBJECTIVE: To investigate the effects and mechanisms of low-dose hydrocortisone on myocardial injury in early septic shock rats. METHODS: Seventy-two healthy male Sprague-Dawley (SD) rats were divided into Sham group, lipopolysaccharide (LPS) model group (LPS group) and low dose hydrocortisone intervention group (LD group) according to the random number table method, with 24 rats in each group. The rat model of septic shock was produced by intravenous injection of LPS at 20 mg/kg. Sham group was injected with an equal amount of physiological saline. The LD group was injected 5 mg/kg of hydrocortisone via right femoral vein after model establishment. Sham group and LPS group were injected with an equal amount of physiological saline. Blood pressure and heart rate (HR) of rats in each group were continuously monitored. In each group, 8 rats were sacrificed for arterial blood gas analysis at 0, 3 and 6 hours after model establishment, and the level of plasma N-terminal B-type brain natriuretic peptide precursor (NT-proBNP) was detected by enzyme linked immunosorbent assay (ELISA). The expressions of cleaved-caspase-3 and nuclear factor-κB p65 (NF-κB p65) were detected by Western Blot. Myocardial tissue was harvested 6 hours after model establishment, the histopathological changes were observed by hematoxylin eosin (HE) staining, and the apoptosis rate of myocardial cells was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL). RESULTS: After LPS injection, mean arterial pressure (MAP) decreased significantly at 1 hour, then gradually increased, and was significantly higher than Sham group at 6 hours. There was no significant change in HR, and the difference was not statistically significant compared with Sham group. Blood lactic acid (Lac), base excess (BE), plasma NT-proBNP level, myocardial tissue caspase-3 and NF-κB p65 expression increased with the extension of time, all reach the peak in 6 hours, and significantly higher than Sham group. After early treatment with low-dose hydrocortisone in septic shock, MAP showed an increasing trend and Lac, BE decreased slowly. At 6 hours, MAP, Lac and BE were significantly lower than those in the LPS group [MAP (mmHg, 1 mmHg = 0.133 kPa): 98.6±7.5 vs. 106.1±8.5, Lac (mmol/L): 1.29±0.08 vs. 2.42±0.37, BE (mmol/L): 4.45±0.57 vs. 8.18±1.03, all P < 0.05]. The level of plasma NT-proBNP, and the expressions of caspase-3 and NF-κB p65 in myocardial tissue were significantly lower than those in LPS group at 3 hours and 6 hours after low-dose hydrocortisol treatment [NT-proBNP (ng/L): 2 740.56±97.31 vs. 4 425.60±743.32 at 3 hours, 2 638.81±205.12 vs. 4 993.01±373.78 at 6 hours; caspase-3/GAPDH: 0.567±0.045 vs. 0.841±0.162 at 3 hours, 0.496±0.071 vs. 1.116±0.172 at 6 hours; NF-κB p65/GAPDH: 0.852±0.734 vs. 1.232±0.115 at 3 hours, 0.783±0.047 vs. 1.383±0.215 at 6 hours, all P < 0.05]. HE staining results showed that myocardial cells in the LPS group were broken and inflammatory cells infiltrated. The myocardial histopathological changes in LD group were significantly less than those in LPS group. TUNEL staining showed that the apoptosis of myocardial cells in LPS group increased, and the apoptosis rate was significantly higher than that in Sham group [(82.41±1.57)% vs. (5.77±0.69)%, P < 0.05]. The apoptosis rate in LD group was significantly lower than that in LPS group [(27.82±1.77)% vs. (82.41±1.57)%, P < 0.05]. CONCLUSIONS: Low-dose hydrocortisone plays a protective role in the myocardial injury of early septic shock, and its mechanism may be related to the inhibition of caspase-3 and NF-κB p65 expression, the reduction of apoptosis rate and myocardial inhibition.

The Association Between XPG Gene Polymorphism and Gastric Cancer Risk.

PURPOSE: Studies exploring the association between the Xeroderma pigmentosum group G (XPG) gene polymorphisms and gastric cancer (GC) risk provide conflicting findings. Thus, this meta-analysis was performed. MATERIALS AND METHODS: The PubMed and EMBASE databases were comprehensively searched to identify studies for the inclusion in the meta-analysis. The strength of the association was evaluated by calculating pooled odds ratios and 95% confidence intervals. RESULTS: Nine case-control studies involving 3540 cases and 3953 controls were included in the meta-analysis, which revealed that the XPG rs751402 polymorphism is positively associated with GC risk and could be viewed as a risk factor of GC in three genetic models. CONCLUSION: The XPG gene rs751402 polymorphism is associated with an increased risk of GC in Chinese Han populations. This finding should be verified by larger studies that include additional ethnic groups.