Glioblastomas with copy number gains in EGFR and RNF139 show increased expressions of carbonic anhydrase genes transformed by ENO1

RNF149 confers cisplatin resistance in esophageal squamous cell carcinoma via destabilization of PHLPP2 and activating PI3K/AKT signalling

Chemo-resistance has been identified as a crucial factor contributing to tumor recurrence and a leading cause of worse prognosis in patients with ESCC. Therefore, unravel the critical regulators and effective strategies to overcome drug resistance will have a significant clinical impact on the disease. In our study we found that RNF149 was upregulated in ESCC and high RNF149 expression was associated with poor prognosis with ESCC patients. Functionally, we have demonstrated that overexpression of RNF149 confers CDDP resistance to ESCC; however, inhibition of RNF149 reversed this phenomenon both in vitro and in vivo. Mechanistically, we demonstrated that RNF149 interacts with PH domain and leucine rich repeat protein phosphatase 2 (PHLPP2) and induces E3 ligase-dependent protein degradation of PHLPP2, substantially activating the PI3K/AKT signalling pathway in ESCC. Additionally, we found that inhibition of PI3K/AKT signalling pathway by AKT siRNA or small molecule inhibitor significantly suppressed RNF149-induced CDDP resistance. Importantly, RNF149 locus was also found to be amplified not only in ESCC but also in various human cancer types. Our data suggest that RNF149 might function as an oncogenic gene. Targeting the RNF149/PHLPP2/PI3K/Akt axis may be a promising prognostic factor and valuable therapeutic target for malignant tumours.

Distribution of Monocarboxylate Transporters in Brain and Choroid Plexus Epithelium

The choroid plexus (CP) plays central roles in regulating the microenvironment of the central nervous system by secreting the majority of cerebrospinal fluid (CSF) and controlling its composition. A monolayer of epithelial cells of CP plays a significant role in forming the blood-CSF barrier to restrict the movement of substances between the blood and ventricles. CP epithelial cells are equipped with transporters for glucose and lactate that are used as energy sources. There are many review papers on glucose transporters in CP epithelial cells. On the other hand, distribution of monocarboxylate transporters (MCTs) in CP epithelial cells has received less attention compared with glucose transporters. Some MCTs are known to transport lactate, pyruvate, and ketone bodies, whereas others transport thyroid hormones. Since CP epithelial cells have significant carrier functions as well as the barrier function, a decline in the expression and function of these transporters leads to a poor supply of thyroid hormones as well as lactate and can contribute to the process of age-associated brain impairment and pathophysiology of neurodegenerative diseases. In this review paper, recent findings regarding the distribution and significance of MCTs in the brain, especially in CP epithelial cells, are summarized.

Early maternal deprivation impairs learning and memory and alters hippocampal gene expression in adult male rats

Maternal deprivation (MD) in early life severely disrupts hippocampal development, leading to persistent cognitive and behavior deficits. The current study uncovered that early MD (P1-P21) impaired spatial learning and memory capacity detected by Morris water maze (MWM) tests from juvenile (P31) to adult (P81) rats compared to age-matched controls. And the protein expression in hippocampus were detected by two-dimensional gel electrophoresis (2-DE) before MWM, respectively. Protein changes in hippocampal were examined to identify the molecular pathways underlying MD-induced hippocampal dysfunction. There were 11 differentially expressed proteins analyzed between adult MD and control male rats, while the 8 proteins were then identified by UPLC-ESI-Q-TOF-MS. Gene Ontology (GO) annotations of the identified proteins were related to neuronal and glial cytoskeletal dynamics, membrane signaling, stress responses, biosynthesis, and metabolism. The different expression proteins spectrin alpha chain, non-erythrocytic 1 (Sptan1), ATP-citrate synthase (Acly), and heat shock protein 90-alpha (Hsp90aa1) have been verified by western blot analysis, and their expression levels showed consistent with 2-DE analysis. In addition, glial fibrillary acidic protein (GFAP) was also found reduced in adult hippocampus of MD rats. This study identifies candidate proteins encompassing a range of functional categories that may contribute to persistent learning and memory deficits due to early life MD.

A molecular signature associated with prolonged survival in glioblastoma patients treated with regorafenib

BACKGROUND

Patients with glioblastoma (GBM) have a dramatically poor prognosis. The recent REGOMA trial suggested an overall survival (OS) benefit of regorafenib in recurrent GBM patients. Considering the extreme genetic heterogeneity of GBMs, we aimed to identify molecular biomarkers predictive of differential response to the drug.

METHODS

Total RNA was extracted from tumor samples of patients enrolled in the REGOMA trial. Genome-wide transcriptome and micro (mi)RNA profiles were associated with patients' OS and progression-free survival.

RESULTS

In the first step, a set of 11 gene transcripts (HIF1A, CTSK, SLC2A1, KLHL12, CDKN1A, CA12, WDR1, CD53, CBR4, NIFK-AS1, RAB30-DT) and 10 miRNAs (miR-93-5p, miR-203a-3p, miR-17-5p, let-7c-3p, miR-101-3p, miR-3607-3p, miR-6516-3p, miR-301a-3p, miR-23b-3p, miR-222-3p) was filtered by comparing survival between regorafenib and lomustine arms. In the second step, a mini-signature of 2 gene transcripts (HIF1A, CDKN1A) and 3 miRNAs (miR-3607-3p, miR-301a-3p, miR-93-5p) identified a subgroup of patients showing prolonged survival after regorafenib administration (median OS range, 10.6-20.8 mo).

CONCLUSIONS

The study provides evidence that a signature based on the expression of 5 biomarkers could help identify a subgroup of GBM patients exhibiting a striking survival advantage when treated with regorafenib. Although the presented results must be confirmed in larger replication cohorts, the study highlights potential biomarker options to help guide the clinical decision among regorafenib and other treatments in patients with relapsing GBM.

Carbonic Anhydrase XII is a Clinically Significant, Molecular Tumor-Subtype Specific Therapeutic Target in Glioma with the Potential to Combat Invasion of Brain Tumor Cells

Background

The metabolic enzyme carbonic anhydrase 12 (CA12/CAXII) emerges as a promising cancer therapeutic target with drug development projects underway. Previous reports proposed the relevance of CA12 in the context of glioma but are limited in patient data quantity, ignore ethnic diversity of patients or rely on semi-quantitative, thereby out of date, methodology. Moreover, little is known on the association of CA12 to brain tumor stemness or on the effect of anti-CAXII-directed monotherapies on glioma stem cells (GSCs), in particular their response regarding mesenchymal differentiation status.

Methods

We performed in silico analysis on three independent, large-scale patient datasets interrogating state of the art molecular diagnostics alongside clinical outcomes. We analyzed CAXII abundance on a collection of GSCs and functionally tested their response to exposure to CAXII blocking antibody 6A10.

Results

CA12 is highly expressed in glial tumors compared with normal tissue and predicts for poor clinical course of tumor patients. CA12 expression in glioblastoma significantly correlates with clinically established, molecular markers of IDH1^WT DNA, WHO grade IV or absence of 1p/19q chromosome arm co-deletion. Furthermore, tumors with elevated CA12 cluster into the mesenchymal transcription subclass of the disease. CAXII abundance in different GSCs ranges from almost absent to high levels and does not correlate to stem cell marker CD133/AC133 cell surface expression. Moreover, aiming to pharmacologically block CAXII in our cells with antibody 6A10 caused significant functional response only in one of the tested GSCs models, featuring suppression of cell invasion accompanied by reduction of ZEB1 protein and other stem cell markers.

Conclusion

CA12 represents a clinically relevant and molecular brain tumor-subtype specific therapeutic target. Our correlative data from experimental and clinical samples does not support CA12/CAXII to be GSC specific. 6A10 possesses promising potential to impede the invasive capacity of glioma cells and supports the emerging concept that CAXII interacts with cancer EMT programs. However, further mechanistic studies are required to comprehensively assess the therapeutic potential of 6A10 and to identify different resistance mechanisms of GSCs.

A Novel RNF139 Mutation in Hemangioblastomas: Case Report

Hemangioblastomas (HBs) are classified as grade I tumors with uncertain origin according to the World Health Organization's classification system. HBs are characterized by rich mesenchymal cells and abundant capillaries. It has been shown that tumorigenesis of HBs depends on mutational inactivation of Von Hippel-Lindau (VHL) tumor suppressor gene. Therefore, the majority of patients will undergo VHL single gene test, and sequencing scheme is rarely used in clinic. In this study, we described a girl and her father successively found to have HBs within half a year. The results of next-generation sequencing (NGS) and Sanger sequencing analysis showed that both of them carried heterozygous mutation of RNF139 p.Q650R. This mutation was interpreted as Pathogenic variation based on the American College of Medical Genetics and Genomics (ACMG) guideline. Sanger sequencing was performed with other family members. No mutation on rs118184842 locus of RNF139 gene was found in the samples from the girl's mother, uncle and aunt. This report supports that the novel mutation of RNF139 p.Q650R probably serve as a key role in HBs progression.

A RNA sequencing-based six-gene signature for survival prediction in patients with glioblastoma

Glioblastoma (GBM) is an aggressive tumor of the central nervous system that has poor prognosis despite extensive therapy. Therefore, it is essential to identify a gene expression-based signature for predicting GBM prognosis. The RNA sequencing data of GBM patients from the Chinese Glioma Genome Atlas (CGGA) and The Cancer Genome Atlas (TCGA) databases were employed in our study. The univariate and multivariate regression models were utilized to assess the relative contribution of each gene to survival prediction in both cohorts, and the common genes in two cohorts were identified as a final prognostic model. A prognostic risk score was calculated based on the prognostic gene signature. This prognostic signature stratified the patients into the low- and high-risk groups. Multivariate regression and stratification analyses were implemented to determine whether the gene signature was an independent prognostic factor. We identified a 6-gene signature through univariate and multivariate regression models. This prognostic signature stratified the patients into the low- and high-risk groups, implying improved and poor outcomes respectively. Multivariate regression and stratification analyses demonstrated that the predictive value of the 6-gene signature was independent of other clinical factors. This study highlights the significant implications of having a gene signature as a prognostic predictor in GBM, and its potential application in personalized therapy.

Computational identification of specific genes for glioblastoma stem-like cells identity

Glioblastoma, the most malignant brain cancer, contains self-renewing, stem-like cells that sustain tumor growth and therapeutic resistance. Identifying genes promoting stem-like cell differentiation might unveil targets for novel treatments. To detect them, here we apply SWIM - a software able to unveil genes (named switch genes) involved in drastic changes of cell phenotype - to public datasets of gene expression profiles from human glioblastoma cells. By analyzing matched pairs of stem-like and differentiated glioblastoma cells, SWIM identified 336 switch genes, potentially involved in the transition from stem-like to differentiated state. A subset of them was significantly related to focal adhesion and extracellular matrix and strongly down-regulated in stem-like cells, suggesting that they may promote differentiation and restrain tumor growth. Their expression in differentiated cells strongly correlated with the down-regulation of transcription factors like OLIG2, POU3F2, SALL2, SOX2, capable of reprogramming differentiated glioblastoma cells into stem-like cells. These findings were corroborated by the analysis of expression profiles from glioblastoma stem-like cell lines, the corresponding primary tumors, and conventional glioma cell lines. Switch genes represent a distinguishing feature of stem-like cells and we are persuaded that they may reveal novel potential therapeutic targets worthy of further investigation.

Group 3 medulloblastoma in a patient with a GYS2 germline mutation and glycogen storage disease 0a

Glycogen storage disease (GSD) 0a is a rare congenital metabolic disease with symptoms in infancy and childhood caused by biallelic GYS2 germline variants. A predisposition to cancer has not been described yet. We report here a boy with GSD 0a, who developed a malignant brain tumor at the age of 4.5 years. The tumor was classified as a group 3 medulloblastoma, and the patient died from cancer 27 months after initial tumor diagnosis. This case appears interesting as group 3 medulloblastoma is so far not known to arise in hereditary syndromes and the biology of sporadic group 3 medulloblastoma is largely unknown.