Complex role of connexin 43 in astrocytic tumors and possible promotion of glioma­associated epileptic discharge (Review).

Connexin (Cx)43 is a multifunction protein which forms gap junction channels and hemi­channels. It also contains abundant binding domains which possess the ability to interact with certain Cx43­associated proteins and therefore serve a fundamental role in various physiological and pathological functions. However, the understanding of the association between cancer and Cx43 along with Cx43­gap junctions (GJ) remains unclear. All available data illustrate that Cx43 and its associated GJ serve important functions in cancers. The expression levels of Cx43 demonstrate a downward trend and an increase in the levels of malignancy, particularly in astrocytomas. The GJ intercellular communication activity in glioma cells can be adjusted via Cx43 phosphorylation and through the combination of Cx43 and its associated protein. Available evidence reveals Cx43 as a tumor­inhibiting factor that suppresses glioma growth and proliferation. However, its mechanism is also regarded as complicated and ambiguous. Furthermore, it is apparent that Cx43­GJ and the carboxyl tail may contribute to glioma growth and proliferation too. However, this valuable role could be weakened by its effects on migration and invasiveness. The detailed mechanism remains unclear and full of controversies. Cx43 can enhance the motor ability and invasiveness of astrocytic glioma cells. It is also able to influence glioma cells to detach from the tumor core to the peritumoral neocortex. This peritumoral region has recently been regarded as the basic focus of glioma­associated seizure. Thus, Cx43 may take part in the onset and development of glioma­associated epileptic discharge. In addition, change and increase of Cx43 expression in GJs has been observed in seizure perilesional tissue, which is associated with brain tumors. Cx43 or GJ/hemi­channels exert enduring effects in the promotion of glioma­associated epileptic release through direct mass effects and change of the tumor microenvironment. However, there are still a number of issues concerning this aspect that require further exploration. Cx43, as a potential treatment target against this incurable disease and its common symptom of epilepsy, requires further investigation.

Biomarkers related with seizure risk in glioma patients: A systematic review.

Increasing evidence indicates that genetic biomarkers play important roles in the development of glioma-associated seizures. Thus, we performed a systematic review to summarise biomarkers that are associated with seizures in glioma patients. An electronic literature search of public databases (PubMed, Embase and Medline) was performed using the keywords glioma, seizure and epilepsy. A totall of 26 eligible studies with 2224 cases were included in this systematic review of publications to 20 June, 2016. Genetic biomarkers such as isocitrate dehydrogenase 1 (IDH1) mutations, low expression of excitatory amino acid transporter 2 (EAAT2), high xCT expression, overexpression of adenosine kinase (ADK) and low expression of very large G-protein-coupled receptor-1 (VLGR1) are primarily involved in synaptic transmission, whereas BRAF mutations, epidermal growth factor receptor (EGFR) amplification, miR-196b expression and low ki-67 expression are associated with regulation of cell proliferation. However, there is limited evidence regarding the roles of RAD50 interactor 1 (RINT1) and olig2 in epileptogenesis among glioma patients. Glioma-related seizure was related to the dysfunction of tumor microenvironment. Our findings may provide new mechanistic insights into targeted therapy for glioma-related seizures and may result in the development of multi-target therapies.

Significance of the prognostic nutritional index in patients with glioblastoma: A retrospective study.

OBJECTIVE: Accumulating evidence demonstrates that prognostic nutritional index(PNI) is linked to the clinical outcome of patients with malignant tumors, but few studies had investigated the clinical significance of PNI in glioblastoma multiforme(GBM). This study aimed to clarify the association between PNI and the clinical outcome of patients with GBM. METHODS: The clinical data of 84 patients with GBM were retrospectively analyzed. PNI was calculated from the following formula: 10×serum albumin (g/dL)+0.005×total lymphocyte count (per mm3). X-tile software was used to determine the cut-off of PNI and other hematological parameters. GBM patients were dichotomized as two groups based on the PNI cut-off. RESULTS: The optimal PNI cut-off level was 44.4. There were 14 patients with a PNI<44.4 and 70 patients with a PNI≥44.4. The results showed that PNI score was associated with gender, serum albumin, and hemoglobin level. Univariate analysis suggested that age, extent of resection, adjuvant treatment, platelet count and PNI score were predictors of overall survival in patients with GBM. The 1- and 2-survival rates of patients with a PNI<44.4 were 28.60 and 0%, respectively, while the corresponding values for patients with a PNI≥44.4 were 52.90 and 5.70%, respectively. Based on multivariate analysis, a PNI≥44.4 (HR:0.479, 95% CI:0.235-0.975,p=0.042) remained an independent prognostic indicator for a favorable outcome of patients with GBM. Furthermore, patients with a PNI≥44.4 may have a better efficacy of adjuvant treatment than patients with a PNI<44.4 (HR:0.259, 95% CI:0.096-0.700, p=0.008). CONCLUSION: A PNI>44.4 was an independent prognostic parameter of overall survival in patients with GBM and the efficacy of adjuvant treatment. Interventions aimed at correcting the nutritional and immune status of patients with GBM may, therefore, promote the effectiveness of adjuvant treatment and improve the survival outcomes.