LGR6 promotes glioblastoma malignancy and chemoresistance by activating the Akt signaling pathway.

Chemoresistance is the primary cause of the poor outcome of glioblastoma multiforme (GBM) therapy. Leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) is involved in the growth and proliferation of several types of cancer, including gastric cancer and ovarian cancer. Therefore, the aim of the present study was to investigate the role of LGR6 in GBM malignancy and chemoresistance. Cell counting kit-8 and Matrigel®-Transwell assays were conducted to assess GBM cell viability and invasion. The effect of LGR6 on cell cycle progression and activation of Akt signaling was analyzed by performing propidium iodide staining and western blotting, respectively. The results demonstrated that LGR6, a microRNA-1236-3p target candidate, promoted GBM cell viability and invasion, and mediated temozolomide sensitivity in SHG-44 and U251 GBM cells. In addition, LGR6 triggered the activation of the Akt signaling pathway during GBM progression. Collectively, the results of the present study suggested that LGR6 promoted GBM malignancy and chemoresistance, at least in part, by activating the Akt signaling pathway. The results may aid with the identification of a novel therapeutic target and strategy for GBM.

Therapeutic effect of exogenous bone marrow­derived mesenchymal stem cell transplantation on silicosis via paracrine mechanisms in rats.

Silicosis is a well-known occupational disease, characterized by epithelial injury, fibroblast proliferation, expansion of the lung matrix and dyspnea. At present, no effective treatment methods for silicosis have been identified. The present study aimed to investigate the protective potential of exogenous bone marrow-derived mesenchymal stem cell (BMSC) transplantation on experimental silica-induced pulmonary fibrosis in rats and analyze the underlying paracrine mechanisms associated with its therapeutic effects. BMSCs were isolated, cultured and passaged from male Sprague-Dawley (SD) rat bone marrow. Third-generation BMSCs were identified by flow cytometry using FITC staining. Following the successful establishment of the silicosis model, exogenous BMSCs were infused into female adult SD rats via the tail vein. Lungs were evaluated using hematoxylin and eosin (H&E) staining. The expression of interleukin-1 receptor antagonist (IL­1RA), interleukin-1 (IL-1) and tumor necrosis factor α (TNF-α) protein was detected by immunohistochemistry and western blot analysis. Co-localization of sex determining region Y (SRY) and IL-1RA expression was determined by double-label immunofluorescence. The distribution of transplanted BMSCs was tracked by monitoring the expression of SRY in rats. Treatment with BMSCs was found to protect the lungs against injury and fibrosis by the suppression of upregulated IL-1 and TNF-α protein, via triggering IL-1RA secretion. This mechanism was hypothesized to be mediated by paracrine signaling. These results indicate that the release of IL­1RA from BMSCs via paracrine mechanisms significantly blocks the production and/or activity of IL-1 and TNF-α. The present study provides an experimental basis for cellular therapy in silicosis.

Attenuation of brain edema and spatial learning deficits by the inhibition of NADPH oxidase activity using apocynin following diffuse traumatic brain injury in rats.

Diffuse brain injury (DBI) is a leading cause of mortality and disability among young individuals and adults worldwide. In specific cases, DBI is associated with permanent spatial learning dysfunction and motor deficits due to primary and secondary brain damage. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) is a major complex that produces reactive oxygen species (ROS) during the ischemic period. The complex aggravates brain damage and cell death following ischemia/reperfusion injury; however, its role in DBI remains unclear. The present study aimed to investigate the hypothesis that levels of NOX2 (a catalytic subunit of NOX) protein expression and the activation of NOX are enhanced following DBI induction in rats and are involved in aggravating secondary brain damage. A rat model of DBI was created using a modified weight-drop device. Our results demonstrated that NOX2 protein expression and NOX activity were enhanced in the CA1 subfield of the hippocampus at 48 and 72 h following DBI induction. Treatment with apocynin (50 mg/kg body weight), a specific inhibitor of NOX, injected intraperitoneally 30 min prior to DBI significantly attenuated NOX2 protein expression and NOX activation. Moreover, treatment with apocynin reduced brain edema and improved spatial learning function assessed using the Morris water maze. These results reveal that treatment with apocynin may provide a new neuroprotective therapeutic strategy against DBI by diminishing the upregulation of NOX2 protein and NOX activity.