Immune checkpoint molecule herpes virus entry mediator is overexpressed and associated with poor prognosis in human glioblastoma.

BACKGROUND: Dysregulation of immune checkpoint molecules leads to immune evasion in human tumours but has become a viable target for tumour therapy. Here, we examined expression of Herpes virus entry mediator (HVEM), an immune checkpoint molecule, in human glioblastoma (GBM) to assess its potential as a molecular target for treatment. METHODS: Molecular and clinical data from publicly available genomic databases containing WHO grade II-IV human glioma cases (n = 1866) were analyzed. Immunohistochemistry was applied to assess HVEM protein levels in primary tumour sections. Statistical analysis was performed using Matlab and R language. FINDINGS: HVEM was found to be elevated in aggressive gliomas, particularly in the mesenchymal and isocitrate dehydrogenase (IDH) wild-type molecular subtypes of GBM. HVEMhigh tumours tended to be associated with amplification of EGFR and loss of PTEN, while HVEMlow tumours harbored mutations in IDH1 (93%). HVEM exhibited potential as a prognostic marker based on Cox regression and nomogram models. HVEM displayed intra-tumour heterogeneity and was more highly expressed in peri-necrotic and microvascular regions. Gene ontology and pathway analysis revealed enrichment of HVEM in multiple immune regulatory processes, such as suppression of T cell mediated immunity in GBM. Finally, in cell lineage analysis, HVEM was found to be tightly associated with several infiltrating immune and stromal cell types which localized to the tumour microenvironment. INTERPRETATION: Our data highlights the importance of HVEM in the development of GBM and as a potential molecular target in combination with current immune checkpoint blockades for treatment of GBM.

TAGLN2 is a candidate prognostic biomarker promoting tumorigenesis in human gliomas.

BACKGROUND: Transgelin-2 (TAGLN2) is a member of the calponin family of actin-bundling proteins that is involved in the regulation of cell morphology, motility, and cell transformation. Here, the clinical significance and potential function of TAGLN2 in malignant gliomas were investigated. METHODS: Molecular and clinical data was obtained from The Cancer Genome Atlas (TCGA) database. Gene ontology and pathway analysis was used to predict potential functions of TAGLN2. RNA knockdown was performed using siRNA or lentiviral contructs in U87MG and U251 glioma cell lines. Cells were characterized in vitro or implanted in vivo to generate orthotopic xenografts in order to assess molecular status, cell proliferation/survival, and invasion by Western blotting, flow cytometry, and 3D tumor spheroid invasion assay, respectively. RESULTS: Increased TAGLN2 expression was associated with increasing tumor grade (P < 0.001), the mesenchymal molecular glioma subtype and worse prognosis in patients (P < 0.001). Immunohistochemistry performed with anti-TAGLN2 on an independent cohort of patients (n = 46) confirmed these results. Gene silencing of TAGLN2 in U87MG and U251 significantly inhibited invasion and tumor growth in vitro and in vivo. Western blot analysis revealed that epithelial-mesenchymal transition (EMT) molecular markers, such as N-cadherin, E-cadherin, and Snail, were regulated in a manner corresponding to suppression of the EMT phenotype in knockdown experiments. Finally, TAGLN2 was induced ~ 2 to 3-fold in U87MG and U251 cells by TGFß2, which was also elevated in GBM and highly correlated with TAGLN2 mRNA levels (P < 0.001). CONCLUSIONS: Our findings indicate that TAGLN2 exerts a role in promoting the development of human glioma. The regulation and function of TAGLN2 therefore renders it as a candidate molecular target for the treatment of GBM.

High expression of RAB43 predicts poor prognosis and is associated with epithelial-mesenchymal transition in gliomas.

The Ras-related GTP-binding protein (RAB) family plays an important role in regulating signal transduction and cellular processes including vesicle transport, cytoskeleton formation and membrane trafficking. More recently, several RAB members have been reported to promote tumorigenesis in many types of cancers. However, the clinical significance and potential function of RAB43 in gliomas remain unclear. Herein, we found that RAB43 was upregulated and positively correlated with the grade of progression in glioma patients by in silico analysis and immunohistochemistry (IHC). Patients with high RAB43 displayed worse clinical outcomes in comparison to those with low RAB43. RAB43 was also highly expressed in mesenchymal and G3 subtypes, and isocitrate dehydrogenase 1 (IDH1) wild-type gliomas. Moreover, transcriptomic analyses via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed that RAB43­related gene sets were mainly involved in the regulation of cell adhesion and cell migration processes. Further investigation indicated that RAB43 downregulation significantly suppressed the migratory and invasive ability of glioma cells, as well as decreased the expression of epithelial-mesenchymal transition (EMT) markers (N-cadherin, vimentin and Snail). In conclusion, a high level of RAB43 was significantly associated with the malignant phenotypes of gliomas, which suggests that RAB43 may serve as a novel biomarker and a potential therapeutic target for gliomas.

Blockage of GSK3ß-mediated Drp1 phosphorylation provides neuroprotection in neuronal and mouse models of Alzheimer's disease.

It is well established that mitochondrial fragmentation plays a key role in the pathogenesis of Alzheimer's disease (AD). Mitochondrial fission is mediated by dynamin-related protein 1 (Drp1), which is highly expressed in nervous system and regulated by various posttranslational modifications including phosphorylation. We identified glycogen synthase kinase (GSK)3ß-dependent Drp1 phosphorylation at Ser(40) and Ser(44), which increases Drp1 GTPase activity and its mitochondrial distribution and could induce mitochondrial fragmentation. Moreover, neurons transfected with Ser(40)Ser(44) phosphomimic Drp1 showed increased mitochondria fragmentation and were more vulnerable to amyloid-ß (Aß)-induced apoptosis. Therefore, blocking GSK3ß-induced Drp1 phosphorylation may be an effective way to protect neurons from Aß toxicity. To address this, we designed and synthesized an artificial polypeptide named TAT-Drp1-SpS, which could specifically block GSK3ß-induced Drp1 phosphorylation. Our results demonstrated that TAT-Drp1-SpS treatment could significantly reduce Aß-induced neuronal apoptosis in cultured neurons. Notably, TAT-Drp1-SpS administration in hippocampus Cornu Ammonis 1 (CA1) region significantly reduced Aß burden and rescued the memory deficits in AD transgenic mice. Although Aß has multiple targets to exert its neurotoxicity, our findings suggested that GSK3ß-induced mitochondrial fragmentation was, at least partially, mediated by Aß toxicity and contribute to the pathogenesis of AD. Taken together, GSK3ß-induced Drp1 phosphorylation provides a novel mechanism for mitochondrial fragmentation in AD, and our findings suggested a novel therapeutic strategy for AD.