Relationships between PTEN gene mutations and prognosis in glioma: a meta-analysis.

We conducted a meta-analysis in order to investigate the relationships between PTEN gene mutations and the prognosis in glioma. The following electronic databases were searched for relevant articles without any language restrictions: Web of Science (1945 ~ 2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966 ~ 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013). Meta-analyses were conducted using the STATA software (Version 12.0, Stata Corporation, College Station, Texas USA). Hazard ratio (HR) with its corresponding 95 % confidence interval (95%CI) was calculated. Six independent cohort studies with a total of 357 glioma patients met our inclusion criteria. Our meta-analysis results indicated that glioma patients with PTEN gene mutations exhibited a significantly shorter overall survival (OS) than those without PTEN gene mutations (HR = 3.66, 95%CI = 2.02 ~ 5.30, P < 0.001). Ethnicity-stratified subgroup analysis demonstrated that PTEN gene mutations were closely linked to poor prognosis in glioma among Americans (HR = 3.72, 95%CI = 1.72 ~ 5.73, P < 0.001), while similar correlations were not observed among populations in Sweden, Italy, and Malaysia (all P > 0.05). Our meta-analysis provides direct and strong evidences for the speculation of PTEN gene mutations' correlation with poor prognosis of glioma patients.

Physiological effects of microgravity on bone cells.

Life on Earth developed under the influence of normal gravity (1g). With evidence from previous studies, scientists have suggested that normal physiological processes, such as the functional integrity of muscles and bone mass, can be affected by microgravity during spaceflight. During the life span, bone not only develops as a structure designed specifically for mechanical tasks but also adapts for efficiency. The lack of weight-bearing forces makes microgravity an ideal physical stimulus to evaluate bone cell responses. One of the most serious problems induced by long-term weightlessness is bone mineral loss. Results from in vitro studies that entailed the use of bone cells in spaceflights showed modification in cell attachment structures and cytoskeletal reorganization, which may be involved in bone loss. Humans exposed to microgravity conditions experience various physiological changes, including loss of bone mass, muscle deterioration, and immunodeficiency. In vitro models can be used to extract valuable information about changes in mechanical stress to ultimately identify the different pathways of mechanotransduction in bone cells. Despite many in vivo and in vitro studies under both real microgravity and simulated conditions, the mechanism of bone loss is still not well defined. The objective of this review is to summarize the recent research on bone cells under microgravity conditions based on advances in the field.

Role of miRNA-146 in proliferation and differentiation of mouse neural stem cells.

Neural stem cells (NSCs) have been defined as neural cells with the potential to self-renew and eventually generate all cell types of the nervous system. NSCs serve as an ideal cell type for nervous system repair. In the present study, miR-146 overexpression and predicted target (notch 1) were used to study proliferation and differentiation of mouse NSCs. shRNA were used to demonstrate the function of Notch 1 in proliferation of mouse NSCs and luciferase reporter assay was used to assess and confirm the binding sequence of 3'-UTR between Notch 1 and miR-146. Results showed that miR-146 overexpression and knockdown of notch 1 inhibited proliferation of mouse NSCs under serum-free cultural conditions and promoted spontaneous differentiation of mouse NSCs under contained serum cultural conditions respectively. Mouse NSCs spontaneously underwent differentiation into neurogenic cells with contained serum medium. However, when miR-146 was overexpressed, differentiation efficiency of glial cells from NSCs was increased, suggesting that Notch1 promoted NSC proliferation and repressed spontaneous differentiation of NSC in serum-free medium. In conclusion, our results demonstrate that miR-146 promoted spontaneous differentiation of NSCs, and this mechanism was influenced by miR-146, as well as its target (notch 1) and downstream gene.

MicroRNA-320 inhibits cell proliferation in glioma by targeting E2F1.

MicroRNAs (miRs) are a class of small non-coding RNAs that are involved in the regulation of gene expression, and in cancer development and progression. In the present study, miR-320 expression was found to be significantly reduced in glioma tissue in comparison with that in adjacent healthy tissues. In the present study, in vitro analyses demonstrated that overexpression of miR-320 inhibited cell proliferation and metastasis, while antisense miR-320 oligonucleotides enhanced cell proliferation and migration in U251 and SHG-44 glioma cell lines, compared with that in negative control cells. Protein expression of E2F1, a cell-cycle regulator, was negatively regulated by miR-320. Therefore, the present study provides novel insights into the association between miR-320 and glioma development.

Role of microRNAs in osteoblasts differentiation and bone disorders.

Advanced studies of single stranded endogenous ~22 nt microRNAs (miRNAs) have demonstrated their diverse biological functions including control of cell differentiation, cell cycle and pathological conditions. Recent studies suggest the potential application of miRNAs in stem cell engineering. miRNAs play a vital role as post-transcriptional regulators of gene expression which controls osteoblasts-mediated bone formation and osteoclasts related bone remodeling. Transcriptional and post-transcriptional mechanisms regulate the differentiation of osteoblasts and osteogenesis. The differentiation of osteoblasts is a key step in the development of skeletal muscles and it is involved in triggering the signaling pathways. Signaling pathways like TGF&#946;, BMP and Wnt are regulated by miRNAs which in turn, are shown to be associated with bone dynamics and bone disorders. This recap highlights the role of miRNAs in osteoblasts differentiation and emphasizes their potential therapeutic role in metabolic bone disorders.

Downregulation of VMP1 confers aggressive properties to colorectal cancer.

Vacuole membrane protein 1 (VMP1) was recently found to be involved in the process of tumor metastasis and is also considered to play a vital role in balancing apoptosis and autophagy. In the present study, the expression of VMP1 in colorectal cancer and matched adjacent non­cancerous tissues was evaluated by immunohistochemistry (IHC) for studying the role of VMP1 in the process of colorectal cancer. Kaplan­Meier analysis and the log-rank test were used to calculate the correlation of classic clinicopathological characteristics related to survival and the expression of VMP1. In vitro, a VMP1 stable gene silencing cell model was constructed using a lentiviral vector. The invasive ability and proliferation of colorectal cancer cells were evaluated by Transwell and MTT assays, respectively, and the underlying signaling pathway was explored by western blotting. Additionally, drug susceptibility to cisplatin, oxaliplatin and 5-FU was tested before and after VMP1 knockout. Finally, an animal model was constructed to explore the role of VMP1 in the physiopathologic process of colorectal cancer. Our results indicated that VMP1 showed increased expression in the adjacent non-cancer tissues compared with that in the colorectal cancer tissues. For different stages of colorectal cancer, expression of VMP1 had a negative correlation with the malignancy of the cancer. In clinical research, we also found that the median survival of patients with low VMP1 expression was much shorter than the survival of patients with high expression. In vitro, after infection with the lentivirus, cells with VMP1 knockout gained significant aggressive properties in regards to invasion and proliferation, and the mechanisms may be related to the activation of the PI3K/Akt/ZO-1/E-cadherin pathway. We also found that shVMP1 cells were more sensitive to 5-FU, but not cisplatin and oxaliplatin. Finally, we found a higher number of formed nodules in nude mice after intraperitoneal injection with shVMP1 cells in the in vivo study.

Surgical stress induces brain-derived neurotrophic factor reduction and postoperative cognitive dysfunction via glucocorticoid receptor phosphorylation in aged mice.

AIMS: This study explored whether surgical stress-induced glucocorticoid receptor (GR) phosphorylation is related to postoperative cognitive dysfunction (POCD) in aged individuals. Inhibition of GR activation could be an effective treatment for POCD. METHODS: A laparotomy was given to C57/BL6 mice in POCD group both 20 and 6 months old. Animals in control group were treated in identical manners except for laparotomy. Cognitive function was evaluated by Morris water maze and elevated plus maze. Western blot and Elisa assay were used to detect related molecules. Mifepristone and roscovitine were treated as inhibitions of GR phosphorylation. RESULTS: The cognitive function was impaired, and brain-derived neurotrophic factor (BDNF) was found reduced in aged POCD group. GR translocation into nucleus and elevated GR phosphorylation were found in prefrontal cortex of aged POCD mice. Cyclin-dependent Kinase 5 (CDK5), kinase for GR phosphorylation also elevated in aged POCD mice. With GR antagonist and CDK5 inhibitor, reduction of BDNF and cognitive dysfunction in aged mice were both rescued. CONCLUSION: These results presented a mechanism that surgical stress-induced GR phosphorylation contributes to POCD in aged individuals. Inhibition of GR activation and phosphorylation might be a potential treatment target of POCD.

Proteome analysis of the sera from Chinese Parkinson's disease patients.

Clinical proteomics is a powerful tool that can be used to identify proteins that are differentially expressed in disease states, leading to greater understanding of the molecular and cellular events that contribute to disease. The aim of this study was to identify protein changes in the sera from Chinese Parkinson's disease (PD) patients, with the goal of finding biomarkers for PD diagnosis, and to elucidate the events occurring at the onset of PD. Using differential display to identify proteins with altered expression in PD patients, we obtained 15 protein spots corresponding to 13 different gene products that were likely to be involved in PD. Two-dimensional gel electrophoresis and mass spectrometry were used to identify differentially expressed proteins, 7 of which have never previously been associated with PD patients. They are likely to be involved in antioxidation, lipid metabolism, intracellular transport, cell proliferation and immunoregulation. The altered levels of these proteins may be related to the pathophysiological mechanisms of PD. As a result, some of these proteins could be considered as candidate biomarkers.