Mechanistic insight into glioma through spatially multidimensional proteomics.

Characterizing the tumor microenvironment at the molecular level is essential for understanding the mechanisms of tumorigenesis and evolution. However, the specificity of the blood proteome in localized region of the tumor and its linkages with other systems is difficult to investigate. Here, we propose a spatially multidimensional comparative proteomics strategy using glioma as an example. The blood proteome signature of tumor microenvironment was specifically identified by in situ collection of arterial and venous blood from the glioma region of the brain for comparison with peripheral blood. Also, by integrating with different dimensions of tissue and peripheral blood proteomics, the information on the genesis, migration, and exchange of glioma-associated proteins was revealed, which provided a powerful method for tumor mechanism research and biomarker discovery. The study recruited multidimensional clinical cohorts, allowing the proteomic results to corroborate each other, reliably revealing biological processes specific to gliomas, and identifying highly accurate biomarkers.

Intracerebral hemorrhage cadaver model for training in hematoma evacuation under endoscopy.

Neuroendoscopic surgery has been performed as an effective method for intracerebral hemorrhage (ICH). This study describes the know-how of constructing the ICH cadaver model and the training on the main neuroendoscopic procedures for ICH. During the training, operation time of twenty trainees in main stages of craniotomy and corticotomy (stage 2), and hematoma evacuation under endoscopy (stage 3) was recorded. To distinguish factors influencing trainees' surgical proficiency, operation time was calculated according to seniority, experience in neuroendoscopic surgery and training sequence. Questionnaire about validity of model was conducted eventually. Ten ICH cadaver models with bilateral hematoma were constructed. Seven trainees worked with seniority >5 years and eleven had experience in neuroendoscopic surgery. Operation time ranged from 20.6 to 33.4 min in stage 2 and 18.5 to 24.9 min in stage 3. In stage 2, less operation time was needed for trainees with seniority >5 years comparing to trainees with seniority ≦5 years (22.56 ±â€¯1.29 vs 29.25 ±â€¯3.02 min, p < 0.01). In stage 3, significant difference of operation time was found between trainees with experience in neuroendoscopic surgery and trainees without the experience (20.08 ±â€¯1.22 vs 22.02 ±â€¯1.82 min, p = 0.014), and the same between trainees in latter group and in former group (19.75 ±â€¯0.80 vs 22.54 ±â€¯1.45 min, p < 0.01). Questionnaire feedback proved high degree of satisfaction about the training model. Therefore, the ICH cadaver model can assist neurosurgeons with neuroendoscopic treatment learning sessions. Simulation and improvement in neuroendoscopic surgical techniques for ICH treatment were possible with the help of ICH cadaver model.

Giant Serpentine Aneurysm of the Middle Cerebral Artery.

BACKGROUND: Giant serpentine aneurysms (GSAs) are a subgroup of giant intracranial aneurysms, distinct from saccular and fusiform varieties, that are defined as partially thrombosed giant aneurysms with tortuous internal vascular channel. Clinicopathologic characteristics of middle cerebral artery GSAs have been rarely reported in the literature, with discussion of radiologic characteristics only. We clarify patient clinical and neuroradiologic features and discuss the mechanism of formation and progression. CASE DESCRIPTION: A 43-year-old woman presented with a GSA arising from the middle cerebral artery. There was a separate inflow and outflow channel of the aneurysm, with the outflow channel feeding the distal branches of the parent artery and supplying normal brain parenchyma. The GSA was treated successfully by aneurysmectomy and superficial temporal artery-middle cerebral artery bypass followed by proximal occlusion and vascular reconstruction. An aneurysm specimen was examined to correlate pathologic findings and morphologic characteristics. RESULT: Pathologic results showed that thickness of the aneurysmal wall was typically increased and varied, and no internal elastic lamina or endothelial lining could be identified. The sac contained thrombi of various ages with recanalizing vessel formation and chronic inflammation infiltration. Intimal hyperplasia and neoangiogenesis in the wall and hyaline degeneration of the media were observed. Vessels coursing in their adventitia showed mucoid changes, which are responsible for the contrast enhancement of the aneurysmal rim on computed tomography scan. CONCLUSIONS: GSAs are a specific pathologic entity with unique morphologic and pathologic characteristics that can affect intracranial blood vessels. The pathogenic mechanisms are unclear; this report suggests that GSAs may be associated with degeneration of the vascular wall.

The Clinical Significance of O6-Methylguanine-DNA Methyltransferase Promoter Methylation Status in Adult Patients With Glioblastoma: A Meta-analysis.

BACKGROUND AND OBJECTIVE: Promoter status of O6-methylguanine-DNA methyltransferase (MGMT) has been widely established as a clinically relevant factor in glioblastoma (GBM) patients. However, in addition to varied therapy schedule, the prognosis of GBM patients is also affected by variations of age, race, primary or recurrent tumor. This study comprehensively investigated the association between MGMT promoter status and prognosis in overall GBM patients and in different GBM subtype including new diagnosed patients, recurrent patients and elderly patients. METHODS: A comprehensive search was performed using PubMed, EMBASE, Cochrane databases to identify literatures (published from January 1, 2005 to April 1, 2017) that evaluated the associations between MGMT promoter methylation and prognosis of GBM patients. RESULTS: Totally, 66 studies including 7,886 patients met the inclusion criteria. Overall GBM patients with a methylated status of MGMT receiving temozolomide (TMZ)-containing treatment had better overall survival (OS) and progression-free survival (PFS) [OS: hazard ratio (HR) = 0.46, 95% confidence interval (CI): 0.41-0.52, p < 0.001, Bon = 0.017; PFS: HR = 0.48, 95% CI 0.40-0.57, p < 0.001, Bon = 0.014], but no significant advantage on OS or PFS in GBM patients with TMZ-free treatment was observed (OS: HR = 0.97, 95% CI 0.91-1.03, p = 0.08, Bon = 1; PFS: HR = 0.76, 95% CI 0.57-1.02, p = 0.068, Bon = 0.748). These different impacts of MGMT status on OS were similar in newly diagnosed GBM patients, elderly GBM patients and recurrent GBM. Among patients receiving TMZ-free treatment, survival benefit in Asian patients was not observed anymore after Bonferroni correction (Asian OS: HR = 0.78, 95% CI 0.64-0.95, p = 0.02, Bon = 0.24, I2 = 0%; PFS: HR = 0.69, 95% CI 0.50-0.94, p = 0.02, Bon = 0.24). No benefit was observed in Caucasian receiving TMZ-free therapy regardless of Bonferroni adjustment. CONCLUSION: The meta-analysis highlights the universal predictive value of MGMT methylation in newly diagnosed GBM patients, elderly GBM patients and recurrent GBM patients. For elderly methylated GBM patients, TMZ alone therapy might be a more suitable option than radiotherapy alone therapy. Future clinical trials should be designed in order to optimize therapeutics in different GBM subpopulation.

Clustering of self-organizing map identifies five distinct medulloblastoma subgroups.

BACKGROUND: Medulloblastoma is one the most malignant paediatric brain tumours. Molecular subgrouping these medulloblastomas will not only help identify specific cohorts for certain treatment but also improve confidence in prognostic prediction. OBJECTIVE: Currently, there is a consensus of the existences of four distinct subtypes of medulloblastoma. We proposed a novel bioinformatics method, clustering of self-organizing map, to determine the subgroups and their molecular diversity. METHODS: Microarray expression profiles of 46 medulloblastoma samples were analysed and five clusters with distinct demographics, clinical outcome and transcriptional profiles were identified. RESULTS: The previously reported Wnt subgroup was identified as expected. Three other novel subgroups were proposed for later investigation. CONCLUSIONS: Our findings underscore the value of SOM clustering for discovering the medulloblastoma subgroups. When the suggested subdivision has been confirmed in large cohorts, this method should serve as a part of routine classification of clinical samples.

Involvement of ROS-alpha v beta 3 integrin-FAK/Pyk2 in the inhibitory effect of melatonin on U251 glioma cell migration and invasion under hypoxia.

BACKGROUND: Melatonin, a well-known antioxidant, has been shown to possess anti-invasive properties for glioma. However, little is known about the effect of melatonin on glioma cell migration and invasion under hypoxia, which is a crucial microenvironment for tumor progress. In addition, focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (Pyk2) are closely associated with cell migration and invasion. Therefore, we investigated the possible role of these kinases and its related signaling in the regulation of human U251 glioma cells behavior by melatonin under hypoxia. METHODS: The abilities of migration and invasion of U251 glioma cells were determined by wound healing and transwell assay in vitro. The intracellular production of reactive oxygen species (ROS) was measured by using the fluorescent probe 6-carboxy-2', 7'-dichorodihydrofluorescein diacetate (DCFH-DA). Immunofluorescence experiments and western blotting analysis were used to detect the expression level of protein. Small interfering RNAs (siRNA) was used to silence specific gene expression. RESULTS: The pharmacologic concentration (1 mM) of melatonin significantly inhibited the migration and invasion of human U251 glioma cells under hypoxia. The inhibitory effect of melatonin was accompanied with the reduced phosphorylation of FAK and Pyk2, and decreased expression of alpha v beta 3 (αvß3) integrin. Additionally, inhibition of αvß3 integrin by siRNA reduced the phosphorylation of FAK/Pyk2 and demonstrated the similar anti-tumor effects as melatonin, suggesting the involvement of αvß3 integrin- FAK/Pyk2 pathway in the anti-migratory and anti-invasive effect of melatonin. It was also found that melatonin treatment decreased the ROS levels in U251 glioma cells cultured under hypoxia. ROS inhibitor apocynin not only inhibited αvß3 integrin expression and the phosphorylation levels of FAK and Pyk2, but also suppressed the migratory and invasive capacity of U251 glioma cells under hypoxia. CONCLUSIONS: These results suggest that melatonin exerts anti-migratory and anti-invasive effects on glioma cells in response to hypoxia via ROS-αvß3 integrin-FAK/Pyk2 signaling pathways. This provides evidence that melatonin may be a potential therapeutic molecule targeting the hypoxic microenvironment of glioma.

Computational analysis identifies invasion-associated genes in pituitary adenomas.

Pituitary adenomas are considered to be benign tumours. However, they can infiltrate surrounding tissues, which may cause a failure of complete removal during surgical resection. Thus far, no molecular biomarkers have been identified, which are able to reliably predict the behaviour of this type of tumour. In the present study, a list of differentially expressed genes in invasive pituitary adenomas was obtained using a computational bioinformatics analysis on the DNA microarray expression profiles. The gene expression datasets of a total of 16 samples were retrieved from the National Center for Biotechnology Information Gene Expression Omnibus database. The gene set enrichment analysis was later conducted on the significantly (FDR<0.05) differentially expressed genes. A total of 194 genes were identified as differentially expressed. The pathway impact analysis revealed that cell adhesion molecules may be vital in the progression of pituitary adenoma invasion. A total of six genes, claudin 7, contactin associated protein-like 2, integrin α6, junctional adhesion molecule 3, protein tyrosine phosphatase, receptor type C and cadherin-associated protein α1 were identified as molecular biomarkers for pituitary adenoma invasion. The present study identified six novel molecular biomarkers, which may be used for diagnostic or therapeutic purposes. However, further experimental investigations are required to validate the present findings.

[The expression of hepatocyte growth factor and its receptor in brain astrocytomas].

OBJECTIVE: To investigate the expression of hepatocyte growth factor (HGF) mRNA and its receptor (c-Met) mRNA in brain astrocytomas and their relationships with tumor proliferation, angiogenesis, clinical pathology and prognosis. METHODS: The expression of HGF mRNA, c-Met mRNA in the resected tumor tissues of 76 patients with brain astrocytomas, 43 males and 33 females, aged 20 - 71, were detected by in situ hybridization. Immunohistochemistry technique was used to test the expression of proliferating cell nuclear antigen (PCNA) protein and the microvessel density (MVD) was determined by immunohistochemistry with monoclonal antibody against CD34. RESULTS: The positive rates of expression of HGF, c-Met and PCNA in low pathologic grades of brain astrocytoma were 34.5%, 44.8% and 15% +/- 9% respectively, and in high pathologic grades of brain astrocytoma were 34.5%, 44.8% and 48% +/- 12% respectively (P < 0.05). MVD in low and high pathologic grades of brain astrocytoma were 17 +/- 7 and 31 +/- 13 respectively (P < 0.05). The expression of HGF, c-Met, PCNA and CD34 was not related to sex, age, position of tumor and diameter of tumor. The expression of c-Met was related to the expression of HGF, PCNA and the MVD in the tumor tissues of these patients. The pathological grade, position of tumor, HGF, c-Met, PCNA, MVD had a significant influence on the survival time. CONCLUSION: HGF/c-Met plays an important role in the formation and progression of the brain astrocytoma and can promote tumor proliferation and intratumoral microvascular formation, and is closely related to the prognosis of the patients.