CD8+CD103+PD1+TIM3+ T cells in glioblastoma microenvironment correlate with prognosis.

Glioblastoma, isocitrate dehydrogenase-wildtype (GB), is the most common and aggressive primary brain malignancy with poor outcome. Immune checkpoint inhibitors (ICIs) have been tested in GB and, despite disappointing results, the identification of a small subgroup of responders underlies the need to improve our understanding of the tumour microenvironment (TME) immunity. This study aimed to determine whether the expression of selected immune checkpoints on tissue-resident memory T cells (Trm) may predict patient outcome. We conducted a single cohort observational study. Tumour samples were collected from 45 patients with histologically confirmed GB (WHO grade 4) and processed to obtain single-cell suspensions. Patients were assessed for the correlation of Trm phenotype with overall survival (OS) or progression-free survival (PFS) using multiparametric flow cytometry and uni/multivariate analyses. Levels of Trm expressing programmed cell death protein 1 (PD1) and T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) were found to be linked to clinical outcome. Low frequency of Trm expressing PD1 or TIM3 or both markers defined subgroups as independent positive prognostic factors for patient survival. On multivariate analysis, low CD8+CD103+PD1+TIM3+ Trm and Karnofsky performance status (KPS) ≥70 were confirmed to be the most predictive independent factors associated with longer OS (hazard ratios-HR [95%CI]: 0.14 [0.04-0.52] p < 0.001, 0.39 [0.16-0.96] p = 0.04, respectively). The CD8+CD103+ Trm subgroups were also age-related predictors for survival in GB.

Regorafenib and glioblastoma: a literature review of preclinical studies, molecular mechanisms and clinical effectiveness.

Glioblastoma IDH wild type (GBM) is a very aggressive brain tumour, characterised by an infiltrative growth pattern and by a prominent neoangiogenesis. Its prognosis is unfortunately dismal, and the median overall survival of GBM patients is short (15 months). Clinical management is based on bulk tumour removal and standard chemoradiation with the alkylating drug temozolomide, but the tumour invariably recurs leading to patient's death. Clinical options for GBM patients remained unaltered for almost two decades until the encouraging results obtained by the phase II REGOMA trial allowed the introduction of the multikinase inhibitor regorafenib as a preferred regimen in relapsed GBM treatment by the National Comprehensive Cancer Network (NCCN) 2020 Guideline. Regorafenib, a sorafenib derivative, targets kinases associated with angiogenesis (VEGFR 1-3), as well as oncogenesis (c-KIT, RET, FGFR) and stromal kinases (FGFR, PDGFR-b). It was already approved for metastatic colorectal cancers and hepatocellular carcinomas. The aim of the present review is to focus on both the molecular and clinical knowledge collected in these first three years of regorafenib use in GBM.

Extracellular vesicles produced by irradiated endothelial or Glioblastoma stem cells promote tumor growth and vascularization modulating tumor microenvironment.

BACKGROUND: Glioblastoma (GBM) is the most lethal primary brain tumor in adult, characterized by highly aggressive and infiltrative growth. The current therapeutic management of GBM includes surgical resection followed by ionizing radiations and chemotherapy. Complex and dynamic interplay between tumor cells and tumor microenvironment drives the progression and contributes to therapeutic resistance. Extracellular vesicles (EVs) play a crucial role in the intercellular communication by delivering bioactive molecules in the surrounding milieu modulating tumor microenvironment. METHODS: In this study, we isolated by ultracentrifugation EVs from GBM stem-like cell (GSC) lines and human microvascular endothelial cells (HMVECs) exposed or not to ionizing irradiation. After counting and characterization, we evaluated the effects of exposure of GSCs to EVs isolated from endothelial cells and vice versa. The RNA content of EVs isolated from GSC lines and HMVECs exposed or not to ionizing irradiation, was analyzed by RNA-Seq. Periostin (POSTN) and Filamin-B (FLNB) emerged in gene set enrichment analysis as the most interesting transcripts enriched after irradiation in endothelial cell-derived EVs and GSC-derived EVs, respectively. POSTN and FLNB expression was modulated and the effects were analyzed by in vitro assays. RESULTS: We confirmed that ionizing radiations increased EV secretion by GSCs and normal endothelial cells, affected the contents of and response to cellular secreted EVs. Particularly, GSC-derived EVs decreased radiation-induced senescence and promoted migration in HMVECs whereas, endothelial cell-derived EVs promoted tumorigenic properties and endothelial differentiation of GSCs. RNA-Seq analysis of EV content, identified FLNB and POSTN as transcripts enriched in EVs isolated after irradiation from GSCs and HMVECs, respectively. Assays performed on POSTN overexpressing GSCs confirmed the ability of POSTN to mimic the effects of endothelial cell-derived EVs on GSC migration and clonogenic abilities and transdifferentiation potential. Functional assays performed on HMVECs after silencing of FLNB supported its role as mediator of the effects of GSC-derived EVs on senescence and migration. CONCLUSION: In this study, we identified POSTN and FLNB as potential mediators of the effects of EVs on GSC and HMVEC behavior confirming that EVs play a crucial role in the intercellular communication by delivering bioactive molecules in the surrounding milieu modulating tumor microenvironment.

A systematic review on the efficacy of adjunctive surgical strategies during microvascular decompression for trigeminal neuralgia without intraoperative evidence of neurovascular conflict.

Aim of the present study was to conduct a comprehensive review of surgical strategies that can be offered to patients with trigeminal neuralgia undergoing microvascular decompression (MVD) surgery and without intraoperative evidence of neurovascular conflict, with a high pre-operative suspicion of conflict lacking intraoperative confirmation, or individuals experiencing recurrence after previous treatment. This systematic review followed established guidelines (PRISMA) to identify and critically appraise relevant studies. The review question was formulated according to the PICO (P: patients; I: intervention; C: comparison; O: outcomes) framework as follows. For patients with trigeminal neuralgia (P) undergoing MVD surgery (I) without demonstrable preoperative neurovascular conflict, high suspicion of conflict but no intraoperative confirmation or recurrence after previous treatment (C), do additional surgical techniques (nerve combing, neurapraxia, arachnoid lysis) (O) improve pain relief outcomes (O)? The search of the literature yielded a total of 221 results. Duplicate records were then removed (n = [76]). A total of 143 papers was screened, and 117 records were excluded via title and abstract screening; 26 studies were found to be relevant to our research question and were assessed for eligibility. Upon full-text review, 17 articles were included in the review, describing the following techniques; (1) internal neurolysis (n = 6) (2) arachnoid lysis/adhesiolysis (n = 2) (3) neurapraxia (n = 3) (4) partial rhizotomy of the sensory root (n = 4) (5) pontine descending tractotomy (n = 2). The risk of bias was assessed using the ROBINS-I (Risk of Bias in Non-randomized Studies - of Interventions) assessment tool. While the described techniques hold promise, further research is warranted to establish standardized protocols, refine surgical approaches, and comprehensively evaluate long-term outcomes.

Telomerase inhibition in malignant gliomas: a systematic review.

Glioblastoma (GBM) is the most frequent adult malignant brain tumour and despite different therapeutic efforts, the median overall survival still ranges from 14 to 18 months. Thus, new therapeutic strategies are urgently needed. However, the identification of cancer-specific targets is particularly challenging in GBM, due to the high heterogeneity of this tumour in terms of histopathological, molecular, genetic and epigenetic features. Telomerase reactivation is a hallmark of malignant glioma. An activating mutation of the hTERT gene, encoding for the active subunit of telomerase, is one of the molecular criteria to establish a diagnosis of GBM, IDH-wildtype, in the 2021 WHO classification of central nervous system tumours. Telomerase inhibition therefore represents, at least theoretically, a promising strategy for GBM therapy: pharmacological compounds, as well as direct gene expression modulation therapies, have been successfully employed in in vitro and in vivo settings. Unfortunately, the clinical applications of telomerase inhibition in GBM are currently scarce. The aim of the present systematic review is to provide an up-to-date report on the studies investigating telomerase inhibition as a therapeutic strategy for malignant glioma in order to foster the future translational and clinical research on this topic.

Magnetic susceptibility as a 1-year predictor of outcome in familial cerebral cavernous malformations: a pilot study.

OBJECTIVES: To test whether quantitative susceptibility mapping (QSM) of cerebral cavernous malformations (CCMs) assessed at baseline may predict the presence or absence of haemorrhagic signs at 1-year follow-up. METHODS: Familial CCM patients were enrolled in the longitudinal multicentre study Treat-CCM. The 3-T MRI scan allowed performing a semi-automatic segmentation of CCMs and computing the maximum susceptibility in each segmented CCM (QSMmax) at baseline. CCMs were classified as haemorrhagic and non-haemorrhagic at baseline and then subclassified according to the 1-year (t1) evolution. Between-group differences were tested, and the diagnostic accuracy of QSMmax in predicting the presence or absence of haemorrhagic signs in CCMs was calculated with ROC analyses. RESULTS: Thirty-three patients were included in the analysis, and a total of 1126 CCMs were segmented. QSMmax was higher in haemorrhagic CCMs than in non-haemorrhagic CCMs (p < 0.001). In haemorrhagic CCMs at baseline, the accuracy of QSMmax in differentiating CCMs that were still haemorrhagic from CCMs that recovered from haemorrhage at t1 calculated as area under the curve (AUC) was 0.78 with sensitivity 62.69%, specificity 82.35%, positive predictive value (PPV) 93.3% and negative predictive value (NPV) 35.9% (QSMmax cut-off ≥ 1462.95 ppb). In non-haemorrhagic CCMs at baseline, AUC was 0.91 in differentiating CCMs that bled at t1 from stable CCMs with sensitivity 100%, specificity 81.9%, PPV 5.1%, and NPV 100% (QSMmax cut-off ≥ 776.29 ppb). CONCLUSIONS: The QSMmax in CCMs at baseline showed high accuracy in predicting the presence or absence of haemorrhagic signs at 1-year follow-up. Further effort is required to test the role of QSM in follow-up assessment and therapeutic trials in multicentre CCM studies. KEY POINTS: • QSM in semi-automatically segmented CCM was feasible. • The maximum magnetic susceptibility in a single CCM at baseline may predict the presence or absence of haemorrhagic signs at 1-year follow-up. • Multicentric studies are needed to enforce the role of QSM in predicting the CCMs' haemorrhagic evolution in patients affected by familial and sporadic forms.

MRI and Trouillas' grading system of pituitary tumors: the usefulness of T2 signal intensity volumetric values.

PURPOSE: To classify pituitary macroadenomas according to the Trouillas' grading system; to compare this grading system with T2 values of volumetric signal intensity to determine T2 values able to predict the final grade. METHODS: A total of 106 patients with macroadenomas were grouped according to the grading system score combining proliferation and invasiveness criteria of Trouillas' classification. Normalized volumetric signal intensity values were extracted from coronal T2-weighted images (nT2mean, nT2Max, nT2min) and were compared with the final grading score system. RESULTS: Thirty-three patients were in grade 1a (non-invasive, non-proliferative tumors), 17 patients in grade 1b (non-invasive, proliferative tumors), 36 patients in grade 2a (invasive, non-proliferative tumors), and 20 patients in grade 2b (invasive, proliferative tumors). No patient was in grade 3 (metastatic tumors). nT2Max and nT2min were the best quantitative values to discriminate invasive from non-invasive grades; in invasive grades, nT2Max intensity values were higher, and nT2min intensity values were lower than in non-invasive grades. Receiver operating characteristic analysis of nT2 values showed that nT2min values had a better diagnostic performance than nT2Max values because they allowed differentiating with a moderate accuracy invasive tumors (2a or 2b grades) from both non-invasive proliferative tumors (1b) and non-invasive-non proliferative tumors (1a) (2a vs 1b: AUCnT2min = 0.78, 2b vs 1b: AUCnT2min = 0.72, 2a vs 1a: AUCnT2min = 0.72, 2b vs 1a AUCnT2min = 0.69). CONCLUSION: Volumetric nT2Max and nT2min values of MRI might be practical and non-invasive markers for assessing tumor invasiveness although nT2 min signal intensity values have more effects in discriminating tumor's invasive behavior.

Magnetic resonance imaging-derived parameters to predict response to regorafenib in recurrent glioblastoma.

PURPOSE: Regorafenib is a multikinase inhibitor, approved as a preferred regimen for recurrent glioblastoma (rGB). Although its effects on prolonging survival could seem modest, it is still unclear whether a subset of patients, potentially identifiable by imaging biomarkers, might experience a more substantial positive effect. Our aim was to evaluate the potential value of magnetic resonance imaging-derived parameters as non-invasive biomarkers to predict response to regorafenib in patients with rGB. METHODS: 20 patients with rGB underwent conventional and advanced MRI at diagnosis (before surgery), at recurrence and at first follow-up (3 months) during regorafenib. Maximum relative cerebral blood volume (rCBVmax) value, intra-tumoral susceptibility signals (ITSS), apparent diffusion coefficient (ADC) values, and contrast-enhancing tumor volumes were tested for correlation with response to treatment, progression-free survival (PFS), and overall survival (OS). Response at first follow-up was assessed according to Response Assessment in Neuro-Oncology (RANO) criteria. RESULTS: 8/20 patients showed stable disease at first follow-up. rCBVmax values of the primary glioblastoma (before surgery) significantly correlated to treatment response; specifically, patients with stable disease displayed higher rCBVmax compared to progressive disease (p = 0.04, 2-group t test). Moreover, patients with stable disease showed longer PFS (p = 0.02, 2-group t test) and OS (p = 0.04, 2-group t test). ITSS, ADC values, and contrast-enhancing tumor volumes showed no correlation with treatment response, PFS nor OS. CONCLUSION: Our results suggest that rCBVmax of the glioblastoma at diagnosis could serve as a non-invasive biomarker of treatment response to regorafenib in patients with rGB.

Resection versus biopsy for management of primary central nervous system lymphoma: a meta-analysis.

The role of surgery in the management of primary central nervous system lymphomas (PCNSL) is currently confined to diagnosis. However, over recent years, an increasing number of papers have suggested a possible positive prognostic impact of surgery in selected cases. The present work aims to perform a meta-analysis of the available literature evidence. A meta-analysis with meta-regression on the role of surgical resection compared to biopsy in the management of PCNSL was conducted according to the PRISMA statement, searching MEDLINE via PubMed and Embase. The random effect model was used. The quality of evidence was assessed using the GRADE framework. After screening 1395 records, we included 11 papers in our analysis. Patients who underwent surgical resection harbored superficial and single-lesion tumors. At 1-, 2-, and 5-year follow-up, progression-free survival did not differ between the two groups, while overall survival favored resection, even if in a non-significant fashion. Meta-regression analysis showed that the overall survival rate at 2 years, but not at 1 or 5 years, was significantly influenced by tumor location. There were no differences in terms of age, sex, Karnofsky performance status, adjuvant therapy, or procedure-related complications. Overall, the quality of evidence is low. The results of the present meta-analysis do not change the current standard of care for PCNSL. However, surgery could be non-inferior to biopsy with an acceptable risk profile in selected patients harboring single and superficial lesions. The low quality of evidence prompts future randomized studies.

Reliability of intraoperative visual evoked potentials (iVEPs) in monitoring visual function during endoscopic transsphenoidal surgery.

OBJECTIVE: To refine a reliable and reproducible intraoperative visual evoked potentials (iVEPs) monitoring protocol during endoscopic transsphenoidal surgery. To assess the reliability of baseline iVEPs in predicting preoperative visual status and perioperative iVEP variation in predicting postoperative visual outcome. METHODS: Sixty-four patients harboring tumors of the pituitary region were included. All patients underwent endoscopic endonasal approach (EEA) with iVEPs monitoring, using a totally intravenous anesthetic protocol. Ophthalmological evaluation included visual acuity and visual field studies. RESULTS: Preoperatively, visual acuity was reduced in 86% and visual field in 76.5% of cases. Baseline iVEPs amplitude was significantly correlated with preoperative visual acuity and visual field (p = 0.001 and p = 0.0004, respectively), confirming the reliability of the neurophysiological/anesthetic protocol implemented. Importantly, perioperatively the variation in iVEPs amplitude was significantly correlated with the changes in visual acuity (p < 0.0001) and visual field (p = 0.0013). ROC analysis confirmed that iVEPs are an accurate predictor of perioperiative visual acuity improvement, with a 100% positive predictive value in patients with preoperative vision loss. CONCLUSIONS: iVEPs during EEA is highly reliable in describing preoperative visual function and can accurately predict postoperative vision improvement. SIGNIFICANCE: iVEPs represent a promising resource for carrying out a more effective and safe endoscopic transsphenoidal surgery.

An Overview of Recent Advances in Anterior Cervical Decompression and Fusion Surgery.

Anterior cervical diskectomy and fusion (ACDF) has evolved significantly in the last few years with the aim of enhancing effectiveness and safety while reducing hospitalization and healthcare-related costs. Transitioning from iliac crest autografts to allografts minimizes donor-site complications like pain, infections, and hematoma. Allograft options, such as polyetheretherketone (PEEK) and tantalum, vary in their osteoinductive properties and elastic modulus, influencing fusion rates, time, and the rate of subsidence. Recently introduced zero-profile cages offer bone fixation through screws, resulting in reduced blood loss, improved spinal alignment, and decreased complications like dysphagia and adjacent segment disease. Intraoperative neuromonitoring (IONM) has gained widespread use. The North American Spine Society (NASS) 2023 recommendations endorse IONM in cervical deformity corrections and myelopathy cases. Insufficient studies hinder clear radiculopathy recommendations, but emerging research supports IONM for patients at greater risk of C5 nerve root injury or positional injury. Advancements in hemostatic agents, such as gelatin sponges, oxidized cellulose, and fibrin sealants, contribute to safety by reducing postoperative hematoma rates and eliminating the need for drainage. Innovations like the exoscope, endoscope, and computed-tomography (CT) navigation have transformed surgical practices. Exoscopes are emerging as an alternative to microscopes, offering benefits like a smaller footprint, adjustable positioning, lower costs, and shared intraoperative views for educational purposes. The use of endoscope offers the possibility of performing a minimally invasive technique with improved results in terms of cosmesis and patient-perceived outcome. CT navigation can be useful in high-risk procedures, such as cervical plate placement for major instability. This paper provides an overview of cutting-edge technologies in ACDF surgery, emphasizing cage materials and designs, safety measures, and operating room advancements. It also highlights areas for future research, underlining the procedure's continuous evolution.

Neuromodulation for Brain Tumors: Myth or Reality? A Narrative Review.

In recent years, research on brain cancers has turned towards the study of the interplay between the tumor and its host, the normal brain. Starting from the establishment of a parallelism between neurogenesis and gliomagenesis, the influence of neuronal activity on the development of brain tumors, particularly gliomas, has been partially unveiled. Notably, direct electrochemical synapses between neurons and glioma cells have been identified, paving the way for new approaches for the cure of brain cancers. Since this novel field of study has been defined "cancer neuroscience", anticancer therapeutic approaches exploiting these discoveries can be referred to as "cancer neuromodulation". In the present review, we provide an up-to-date description of the novel findings and of the therapeutic neuromodulation perspectives in cancer neuroscience. We focus both on more traditional oncologic approaches, aimed at modulating the major pathways involved in cancer neuroscience through drugs or genetic engineering techniques, and on electric stimulation proposals; the latter is at the cutting-edge of neuro-oncology.

Comparison of combined anterior-posterior and posterior-only approaches for lumbosacral chordomas: a systematic review and meta-analysis of surgical and clinical outcomes.

Lumbosacral chordoma is a slow-growing but locally aggressive tumor, resistant to adjuvant treatments and endowed with dismal prognosis. Surgery is the mainstay of treatment but the choice of surgical approach (the posterior-only approach or the combined anterior-posterior approach) remains an open question due to the need of both pursuing a surgical radicality and preserving the neurologic function. The aim of the study was to compare the surgical and clinical outcomes of these approaches in the management of lumbosacral chordomas. A systematic review and meta-analysis in agreement with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines of papers comparing the outcomes of the two approaches was performed. Ten papers met the inclusion criteria. The combined anterior-posterior approach was more frequently performed for tumors with an upper level beyond S2 (p = 0.012). The 5-year progression-free survival was significantly higher in posterior-only approach compared with the combined anterior-posterior approach (44.7% vs 27.1%, p = 0.049). Adjuvant radiotherapy was added more frequently after a posterior-only approach (p = 0.036) and the rate of complications was significantly lower after a posterior-only approach (p = 0.040). No significant differences in sex, age, tumor diameter, entity of resection, and overall survival were observed. Posterior-only surgical approach may be a reasonable option for lumbosacral chordoma, being associated with comparable entity of surgical resection, reduced complication rate and increased 5-year progression-free survival rate as compared with combined anterior-posterior approach.

Dissecting Stemness in Aggressive Intracranial Meningiomas: Prognostic Role of SOX2 Expression.

Meningiomas are mostly benign tumors that, at times, can behave aggressively, displaying recurrence despite gross-total resection (GTR) and progression to overt malignancy. Such cases represent a clinical challenge, particularly because they are difficult to recognize at first diagnosis. SOX2 (Sex-determining region Y-box2) is a transcription factor with a key role in stem cell maintenance and has been associated with tumorigenesis in a variety of cancers. The purpose of the present work was to dissect the role of SOX2 in predicting the aggressiveness of meningioma. We analyzed progressive/recurrent WHO grade 1−2 meningiomas and WHO grade 3 meningiomas; as controls, non-recurring WHO grade 1 and grade 2 meningioma patients were enrolled. SOX2 expression was evaluated using both immunohistochemistry (IHC) and RT-PCR. The final analysis included 87 patients. IHC was able to reliably assess SOX2 expression, as shown by the good correlation with mRNA levels (Spearman R = 0.0398, p = 0.001, AUC 0.87). SOX2 expression was an intrinsic characteristic of any single tumor and did not change following recurrence or progression. Importantly, SOX2 expression at first surgery was strongly related to meningioma clinical behavior, histological grade and risk of recurrence. Finally, survival data suggest a prognostic role of SOX2 expression in the whole series, both for overall and for recurrence-free survival (p < 0.0001 and p = 0.0001, respectively). Thus, SOX2 assessment could be of great help to clinicians in informing adjuvant treatments during follow-up.

Short tandem repeat profiling for the authentication of cancer stem-like cells.

Colorectal and glioblastoma cancer stem-like cells (CSCs) are essential for translational research. Cell line authentication by short tandem repeat (STR) profiling ensures reproducibility of results in oncology research. This technique enables to identify mislabeling or cross-contamination of cell lines. In our study, we provide a reference dataset for a panel of colorectal and glioblastoma CSCs that allows authentication. Each cell line was entered into the cell Line Integrated Molecular Authentication database 2.1 to be compared to the STR profiles of 4485 tumor cell lines. This article also provides clinical data of patients from whom CSCs arose and data on the parent tumor stage and mutations. STR profiles and information of our CSCs are also available in the Cellosaurus database (ExPASy) as identified by unique research resource identifier codes.

Effects of the Combined Treatment with a G-Quadruplex-Stabilizing Ligand and Photon Beams on Glioblastoma Stem-like Cells: A Magnetic Resonance Study.

Glioblastoma multiforme is a malignant primary brain tumor with a poor prognosis and high rates of chemo-radiotherapy failure, mainly due to a small cell fraction with stem-like properties (GSCs). The mechanisms underlying GSC response to radiation need to be elucidated to enhance sensitivity to treatments and to develop new therapeutic strategies. In a previous study, two GSC lines, named line #1 and line #83, responded differently to carbon ions and photon beams, with the differences likely attributable to their own different metabolic fingerprint rather than to radiation type. Data from the literature showed the capability of RHPS4, a G-quadruplex stabilizing ligand, to sensitize the glioblastoma radioresistant U251MG cells to X-rays. The combined metabolic effect of ligand #190, a new RHPS4-derivative showing reduced cardiotoxicity, and a photon beam has been monitored by magnetic resonance (MR) spectroscopy for the two GSC lines, #1 and #83, to reveal whether a synergistic response occurs. MR spectra from both lines were affected by single and combined treatments, but the variations of the analysed metabolites were statistically significant mainly in line #1, without synergistic effects due to combination. The multivariate analysis of ten metabolites shows a separation between control and treated samples in line #1 regardless of treatment type, while separation was not detected in line #83.

Combining Magnetic Resonance Imaging with Systemic Monocyte Evaluation for the Implementation of GBM Management.

Magnetic resonance imaging (MRI) is the gold standard for glioblastoma (GBM) patient evaluation. Additional non-invasive diagnostic modalities are needed. GBM is heavily infiltrated with tumor-associated macrophages (TAMs) that can be found in peripheral blood. FKBP51s supports alternative-macrophage polarization. Herein, we assessed FKBP51s expression in circulating monocytes from 14 GBM patients. The M2 monocyte phenotype was investigated by qPCR and flow cytometry using antibodies against PD-L1, CD163, FKBP51s, and CD14. MRI assessed morphologic features of the tumors that were aligned to flow cytometry data. PD-L1 expression on circulating monocytes correlated with MRI tumor necrosis score. A wider expansion in circulating CD163/monocytes was measured. These monocytes resulted in a dramatic decrease in patients with an MRI diagnosis of complete but not partial surgical removal of the tumor. Importantly, in patients with residual tumor, most of the peripheral monocytes that in the preoperative stage were CD163/FKBP51s- had turned into CD163/FKBP51s+. After Stupp therapy, CD163/FKBP51s+ monocytes were almost absent in a case of pseudoprogression, while two patients with stable or true disease progression showed sustained levels in such circulating monocytes. Our work provides preliminary but meaningful and novel results that deserve to be confirmed in a larger patient cohort, in support of potential usefulness in GBM monitoring of CD163/FKBP51s/CD14 immunophenotype in adjunct to MRI.

Mir-370-3p Impairs Glioblastoma Stem-Like Cell Malignancy Regulating a Complex Interplay between HMGA2/HIF1A and the Oncogenic Long Non-Coding RNA (lncRNA) NEAT1.

Glioblastoma (GBM) is the most aggressive and prevalent form of a human brain tumor in adults. Several data have demonstrated the implication of microRNAs (miRNAs) in tumorigenicity of GBM stem-like cells (GSCs). The regulatory functions of miRNAs in GSCs have emerged as potential therapeutic candidates for glioma treatment. The current study aimed at investigating the function of miR-370-3p in glioma progression, as aberrant expression of miR-370-3p, is involved in various human cancers, including glioma. Analyzing our collection of GBM samples and patient-derived GSC lines, we found the expression of miR-370-3p significantly downregulated compared to normal brain tissues and normal neural stem cells. Restoration of miR-370-3p expression in GSCs significantly decreased proliferation, migration, and clonogenic abilities of GSCs, in vitro, and tumor growth in vivo. Gene expression analysis performed on miR-370-3p transduced GSCs, identified several transcripts involved in Epithelial to Mesenchymal Transition (EMT), and Hypoxia signaling pathways. Among the genes downregulated by the restored expression of miR-370-3p, we found the EMT-inducer high-mobility group AT-hook 2 (HMGA2), the master transcriptional regulator of the adaptive response to hypoxia, Hypoxia-inducible factor (HIF)1A, and the long non-coding RNAs (lncRNAs) Nuclear Enriched Abundant Transcript (NEAT)1. NEAT1 acts as an oncogene in a series of human cancers including gliomas, where it is regulated by the Epidermal Growth Factor Receptor (EGFR) pathways, and contributes to tumor growth and invasion. Noteworthy, the expression levels of miR-370-3p and NEAT1 were inversely related in both GBM tumor specimens and GSCs, and a dual-luciferase reporter assay proved the direct binding between miR-370-3p and the lncRNAs NEAT1. Our results identify a critical role of miR-370-3p in the regulation of GBM development, indicating that miR-370-3p acts as a tumor-suppressor factor inhibiting glioma cell growth, migration and invasion by targeting the lncRNAs NEAT1, HMGA2, and HIF1A, thus, providing a potential candidate for GBM patient treatment.

Glioblastoma endothelium drives bevacizumab-induced infiltrative growth via modulation of PLXDC1.

Bevacizumab, a VEGF-targeting monoclonal antibody, may trigger an infiltrative growth pattern in glioblastoma. We investigated this pattern using both a human specimen and rat models. In the human specimen, a substantial fraction of infiltrating tumor cells were located along perivascular spaces in close relationship with endothelial cells. Brain xenografts of U87MG cells treated with bevacizumab were smaller than controls (p = 0.0055; Student t-test), however, bands of tumor cells spread through the brain farther than controls (p < 0.001; Student t-test). Infiltrating tumor Cells exhibited tropism for vascular structures and propensity to form tubules and niches with endothelial cells. Molecularly, bevacizumab triggered an epithelial to mesenchymal transition with over-expression of the receptor Plexin Domain Containing 1 (PLXDC1). These results were validated using brain xenografts of patient-derived glioma stem-like cells. Enforced expression of PLXDC1 in U87MG cells promoted brain infiltration along perivascular spaces. Importantly, PLXDC1 inhibition prevented perivascular infiltration and significantly increased the survival of bevacizumab-treated rats. Our study indicates that bevacizumab-induced brain infiltration is driven by vascular endothelium and depends on PLXDC1 activation of tumor cells.

Endothelial trans-differentiation in glioblastoma recurring after radiotherapy.

We hypothesized that in glioblastoma recurring after radiotherapy, a condition whereby the brain endothelium undergoes radiation-induced senescence, tumor cells with endothelial phenotype may be relevant for tumor neovascularization. Matched glioblastoma samples obtained at primary surgery and at surgery for tumor recurrence after radiotherapy, all expressing epidermal growth factor receptor variant III (EGFRvIII), were assessed by a technique that combines fluorescent in situ hybridization (FISH) for the EGFR/CEP7 chromosomal probe with immunostaining for endothelial cells (CD31) and activated pericytes (α Smooth Muscle Actin). Five EGFRvIII-expressing paired primary/recurrent glioblastoma samples, in which the tumor cells showed EGFR/CEP7 amplification, were then assessed by CD31 and α Smooth Muscle Actin immunofluorescence. In glomeruloid bodies, the ratio between CD31+ cells with amplified EGFR/CEP7 signal and the total CD31+ cells was 0.23 ± 0.09 (mean ± sem) and 0.63 ± 0.07 in primary tumors and in recurrent ones, respectively (p < 0.002, Student-t test). In capillaries, the ratio of CD31+ cells with amplified EGFR/CEP7 over the total CD31+ cells lining the capillary lumen was 0.21 ± 0.06 (mean ± sem) and 0.42 ± 0.07 at primary surgery and at recurrence, respectively (p < 0.005, Student-t test). Expression of α Smooth Muscle Actin by cells with EGFR/CEP7 amplification was not observed. Then, in glioblastoma recurring after radiotherapy, where the brain endothelium suffers from radiation-induced cell senescence, tumor-derived endothelium plays a role in neo-vascularization.