Management of Glioblastoma, Present and Future

Effects of the Use of Neuronavigation in Patients with Supratentorial Brain Gliomas: A Cohort Study

OBJECTIVE

Despite the growing acceptance of neuronavigation in the field of neurosurgery, there is limited comparative research with contradictory results. This study aimed to compare the effectiveness (tumor resection rate and survival) and safety (frequency of neurological complications) of surgery for brain gliomas with or without neuronavigation.

METHODS

This retrospective cohort study evaluated data obtained from electronic records of patients who underwent surgery for gliomas at Dr. Alejandro Dávila Bolaños Military Hospital and the Clinic Hospital of Barcelona between July 2016 and September 2022. The preoperative and postoperative clinical and radiologic characteristics were analyzed and compared according to the use of neuronavigation.

RESULTS

This study included 110 patients, of whom 79 underwent surgery with neuronavigation. Neuronavigation increased gross total resection by 57% in patients in whom it was used; gross total resection was performed in 56% of patients who underwent surgery with neuronavigation as compared with 35.5% in those who underwent surgery without neuronavigation (risk ratio [RR], 1.57; P=0.056). The incidence of postoperative neurologic deficits (transient and permanent) decreased by 79% with the use of neuronavigation, (12% vs. 33.3%; RR, 0.21; P=0.0003). Neuronavigation improved survival in patients with grade IV gliomas (15 months vs. 13.8 months), but it was not statistically significant (odds ratio (OR), 0.19; P=0.13).

CONCLUSIONS

Neuronavigation improved the effectiveness (greater gross total resection of tumors) and safety (fewer neurological deficits) of brain glioma surgery. However, neuronavigation does not significantly influence the survival of patients with grade IV gliomas.

The T1/T2 Ratio is Associated With Resectability in Patients With Isocitrate Dehydrogenase-Mutant Astrocytomas Central Nervous System World Health Organization Grades 2 and 3

BACKGROUND AND OBJECTIVES

Isocitrate dehydrogenase (IDH)-mutant astrocytomas central nervous system World Health Organization grade 2 and 3 show heterogeneous appearance on MRI. In the premolecular era, the discrepancy between T1 hypointense and T2 hyperintense tumor volume in absolute values has been proposed as a marker for diffuse tumor growth. We set out to investigate if a ratio of T1 to T2 tumor volume (T1/T2 ratio) is associated with resectability and overall survival (OS) in patients with IDH-mutant astrocytomas.

METHODS

Patient data from 2 centers (Sahlgrenska University Hospital, Center A; LMU University Hospital, Center B) were collected retrospectively. Inclusion criteria were as follows: pre and postoperative MRI scans available for volumetric analysis (I), diagnosis of an IDH-mutant astrocytoma between 2003 and 2021 (II), and tumor resection at initial diagnosis (III). Tumor volumes were manually segmented. The T1/T2 ratio was calculated and correlated with extent of resection, residual T2 tumor volume, and OS.

RESULTS

The study comprised 134 patients with 65 patients included from Center A and 69 patients from Center B. The median OS was 134 months and did not differ between the cohorts (P = .29). Overall, the median T1/T2 ratio was 0.79 (range 0.15-1.0). Tumors displaying a T1/T2 ratio of 0.33 or lower showed significantly larger residual tumor volumes postoperatively (median 17.9 cm3 vs 4.6 cm3, P = .03). The median extent of resection in these patients was 65% vs 90% (P = .03). The ratio itself did not correlate with OS. In multivariable analyses, larger postoperative tumor volumes were associated with shorter survival times (hazard ratio 1.02, 95% CI 1.01-1.03, P < .01).

CONCLUSION

The T1/T2 ratio might be a good indicator for diffuse tumor growth on MRI and is associated with resectability in patients with IDH-mutant astrocytoma. This ratio might aid to identify patients in which an oncologically relevant tumor volume reduction cannot be safely achieved.

Electrochemical biosensors for early diagnosis of glioblastoma

Glioblastoma (GBM) is a highly aggressive and life-threatening neurological malignancy of predominant astrocyte origin. This type of neoplasm can develop in either the brain or the spine and is also known as glioblastoma multiforme. Although current diagnostic methods such as magnetic resonance imaging (MRI) and positron emission tomography (PET) facilitate tumor location, these approaches are unable to assess disease severity. Furthermore, interpretation of imaging studies requires significant expertise which can have substantial inter-observer variability, thus challenging diagnosis and potentially delaying treatment. In contrast, biosensing systems offer a promising alternative to these traditional approaches. These technologies can continuously monitor specific molecules, providing valuable real-time data on treatment response, and could significantly improve patient outcomes. Among various types of biosensors, electrochemical systems are preferred over other types, as they do not require expensive or complex equipment or procedures and can be made with readily available materials and methods. Moreover, electrochemical biosensors can detect very small amounts of analytes with high accuracy and specificity by using various signal amplification strategies and recognition elements. Considering the advantages of electrochemical biosensors compared to other biosensing methods, we aim to highlight the potential application(s) of these sensors for GBM theranostics. The review's innovative insights are expected to antecede the development of novel biosensors and associated diagnostic platforms, ultimately restructuring GBM detection strategies.

Impact of Preoperative Mapping and Intraoperative Neuromonitoring in Minimally Invasive Parafascicular Surgery for Deep-Seated Lesions

BACKGROUND

Transsulcal tubular retractor-assisted minimally invasive parafascicular surgery changes the surgical strategy for deep-seated lesions by promoting a deficit-sparing approach. When integrated with preoperative brain mapping and intraoperative neuromonitoring (IONM), this approach may potentially improve patient outcomes. In this study, we assessed the impact of preoperative brain mapping and IONM in tubular retractor-assisted neuro-oncological surgery.

METHODS

This retrospective single-center cohort study included patients who underwent transsulcal tubular retractor-assisted minimally invasive parafascicular surgery for resection of deep-seated brain tumors from 2016 to 2022. The cohort was divided into 3 groups: group 1, no preoperative mapping or IONM (17 patients); group 2, IONM only (25 patients); group 3, both preoperative mapping and IONM (38 patients).

RESULTS

We analyzed 80 patients (33 males and 47 females) with a median age of 46.5 years (range: 1-81 years). There was no significant difference in mean tumor volume (26.2 cm3 [range 1.07-97.4 cm3]; P = 0.740) and mean preoperative depth of the tumor (31 mm [range 3-65 mm], P = 0.449) between the groups. A higher proportion of high-grade gliomas and metastases was present within group 3 (P = 0.003). IONM was related to fewer motor (P = 0.041) and language (P = 0.032) deficits at hospital discharge. Preoperative mapping and IONM were also related to shorter length of stay (P = 0.008).

CONCLUSIONS

Preoperative and intraoperative brain mapping and monitoring enhance transsulcal tubular retractor-assisted minimally invasive parafascicular surgery in neuro-oncology. Patients had a reduced length of stay and prolonged overall survival. IONM alone reduces postoperative neurological deficit.

Multi-omics approaches establishing histone modification based prognostic model in glioma patients and further verification of the carcinogenesis mechanism

Glioblastoma (GBM) emerges as the most common malignant brain tumor. Histone modifications, as an epigenetic regulatory mechanism of gene expression, are closely associated with malignant tumors. Gene set related to histone modification was extracted from the MSigDB database, and scored by the function of AddModuleScore. Pearson correlation analysis was utilized using the "rcorr" function of "Hmisc" R package. Genes were screened out using the LASSO Cox analysis. TCGA-GBM and CGGA_array_301 cohorts were employed for constructing model and validation. We calculated immune infiltration scores using microenvironment cell populations counter (MCPcounter), single-sample gene set enrichment analysis (ssGSEA), and xCell algorithms. U87-MG and CHG-5 cell lines were utilized to evaluate expression level of TMEM176A by western blot (WB). Transwell, EDU, colony formation analysis (CFA), and CKK-8 assays were conducted to investigate cell proliferation and migration rate. The malignant cells in GBM patients exhibited notable activation in the TGF-β and hypoxia pathway. Histone modifications were associated with adhesion and neuron development in GBM. We identified a model with five significant genes, namely NBEAL1, AEBP1, TMEM176A, FASTK, and CD81, with prognostic efficacy. Additionally, we observed increased infiltration of T cells and CD8+ T cells in the high-risk (HR) group. 5-Fluorouracil_1073 and Taselisib_1561 were predicted as potential treatment options for GBM patients, while ABT737_1910 and Wnt_C59-1622 exhibited superior response in GBM patients of the HR group. A spike in the TP53 mutation rate was observed in the HR group. TMEM176A played a role in regulating cell proliferation and migration in vitro. We presented a novel prognostic model for patients with GBM, based on histone modification-related genes. In addition, we identified the crucial role of the TMEM176A in the regulation of GBM carcinogenic phenotypes for the first time.

Diffusion Weighted Imaging in Neuro-Oncology: Diagnosis, Post-Treatment Changes, and Advanced Sequences-An Updated Review

DWI is an imaging technique commonly used for the assessment of acute ischemia, inflammatory disorders, and CNS neoplasia. It has several benefits since it is a quick, easily replicable sequence that is widely used on many standard scanners. In addition to its normal clinical purpose, DWI offers crucial functional and physiological information regarding brain neoplasia and the surrounding milieu. A narrative review of the literature was conducted based on the PubMed database with the purpose of investigating the potential role of DWI in the neuro-oncology field. A total of 179 articles were included in the study.

Glioma is associated with exposure to legacy and alternative per- and polyfluoroalkyl substances

Data on the occurrences of legacy and alternative per- and polyfluoroalkyl substances (PFASs) in glioma are scarce. It remains unclear if PFASs exposure is related to the prevalence of glioma. A total of 137 glioma and 40 non-glioma brain tissue samples from patients recruited from the Nanfang Hospital, South China were analyzed for 17 PFAS compounds. Perfluorohexanoic acid, perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorooctane sulfonamide (FOSA), and 6:2 chlorinated polyfluorinated ether sulfonate were frequently detected (> 60 %) in glioma. The total concentrations (range; median) of 17 PFASs in glioma (0.20-140; 3.1 ng g^-1) were slightly higher than those in non-glioma (0.35-32; 2.2 ng g^-1), but without statistical significance. The PFAS concentrations in males were statistically higher (p < 0.05) than those in females. Elevated glioma grades were associated with higher concentrations of PFOA, PFOS, and FOSA. Positive correlations were observed between PFAS concentrations (especially for PFOA) and Ki-67 or P53 expression, pathological molecular markers of glioma. Our findings suggested that exposure to PFASs might increase the probability to develop glioma. This is the first case study demonstrating associations between PFASs exposure and brain cancer. More evidences and potential pathogenic mechanisms warranted further investigations.

Unplanned intensive care unit readmission after surgical treatment in patients with newly diagnosed glioblastoma - forfeiture of surgically achieved advantages?

Postoperative intensive care unit (ICU) monitoring is an established option to ensure patient safety after resection of newly diagnosed glioblastoma. In contrast, secondary unplanned ICU readmission following complicating events during the initial postoperative course might be associated with severe morbidity and impair initially intended surgical benefit. In the present study, we assessed the prognostic impact of secondary ICU readmission and aimed to identify preoperatively ascertainable risk factors for the development of such adverse events in patients treated surgically for newly diagnosed glioblastoma. Between 2013 and 2018, 240 patients were surgically treated for newly diagnosed glioblastoma at the authors' neuro-oncological center. Secondary ICU readmission was defined as any unplanned admission to the ICU during initial hospital stay. A multivariable logistic regression analysis was performed to identify preoperatively measurable risk factors for unplanned ICU readmission. Nineteen of 240 glioblastoma patients (8%) were readmitted to the ICU. Median overall survival of patients with unplanned ICU readmission was 9 months compared to 17 months for patients without secondary ICU readmission (p=0.008). Multivariable analysis identified "preoperative administration of dexamethasone > 7 days" (p=0.002) as a significant and independent predictor of secondary unplanned ICU admission. Secondary ICU readmission following surgery for newly diagnosed glioblastoma is significantly associated with poor survival and thus may negate surgically achieved prerequisites for further treatment. This underlines the indispensability of precise patient selection as well as the importance of further scientific debate on these highly relevant aspects for patient safety.

Unveiling the Mechanism of the Traditional Korean Medicinal Formula FDY003 on Glioblastoma Through a Computational Network Pharmacology Approach

Glioblastoma (GBM) is the most common type of primary malignant tumor that develops in the brain, with 0.21 million new cases per year globally and a median survival period of less than 2 years after diagnosis. Traditional Korean medicines have been increasingly suggested as effective and safe therapeutic strategies for GBM. However, their pharmacological effects and mechanistic characteristics remain to be studied. In this study, we employed a computational network pharmacological approach to determine the effects and mechanisms of the traditional Korean medicinal formula FDY003 on GBM. We found that FDY003 treatment decreased the viability of human GBM cells and increased their response to chemotherapeutics. We identified 10 potential active pharmacological compounds of FDY003 and 67 potential GBM-related target genes and proteins. The GBM-related targets of FDY003 were signaling components of various crucial GBM-associated pathways, such as PI3K-Akt, focal adhesion, MAPK, HIF-1, FoxO, Ras, and TNF. These pathways are functional regulators for the determination of cell growth and proliferation, survival and death, and cell division cycle of GBM cells. Together, the overall analyses contribute to the pharmacological basis for the anti-GBM roles of FDY003 and its systematic mechanisms.

Manganese Dioxide-Based Nanocarrier Delivers Paclitaxel to Enhance Chemotherapy against Orthotopic Glioma through Hypoxia Relief

Chemotherapy plays an important role in treating cancers in clinic. Hypoxia-mediated chemoresistance remains a major hurdle for effective tumor chemotherapy. Herein, a new class of tLyP-1-modified dopamine (DOPA)-β-cyclodextrin (CD)-coated paclitaxel (PTX)- and manganese dioxide (MnO₂ )-loaded nanoparticles (tLyP-1-CD-DOPA-MnO₂ @PTX) is developed to enhance glioma chemotherapy. The nanomedicine delivered to the tumor site decomposes in response to the weak acidity and high hydrogen peroxide in the tumor microenvironment (TME), resulting in collapse of the system to release PTX and generates Mn²⁺ and O₂ . In a rat model of intracranial glioma, tLyP-1-CD-DOPA-MnO₂ @PTX can efficiently pass through the blood-brain-barrier to accumulate in tumor sites. The hypoxia in TME can be relieved via O₂ generated by MnO₂ and the reactive oxygen species produced by Mn²⁺ can kill tumor cells. The tLyP-1-CD-DOPA-MnO₂ @PTX nanoparticles exert a remarkable antitumor effect by promoting apoptosis and inhibiting proliferation of tumor cells in addition to enabling real-time tumor monitoring with magnetic resonance imaging. This MnO₂ -based theranostic medicine will offer a novel strategy to simultaneously enhance chemotherapy and achieve real-time imaging of therapeutic process in glioma treatment.

LncRNA PELATON, a Ferroptosis Suppressor and Prognositic Signature for GBM

PELATON is a long noncoding RNA also known as long intergenic nonprotein coding RNA 1272 (LINC01272). The known reports showed that PELATON functions as an onco-lncRNA or a suppressor lncRNA by suppressing miRNA in colorectal cancer, gastric cancer and lung cancer. In this study, we first found that PELATON, as an onco-lncRNA, alleviates the ferroptosis driven by mutant p53 and promotes mutant p53-mediated GBM proliferation. We also first confirmed that PELATON is a new ferroptosis suppressor lncRNA that functions as a ferroptosis inhibitor mainly by mutant P53 mediating the ROS ferroptosis pathway, which inhibits the production of ROS, reduces the levels of divalent iron ions, promotes the expression of SLC7A11, and inhibits the expression of ACSL4 and COX2.PELATON can inhibit the expression of p53 in p53 wild-type GBM cells and regulate the expression of BACH1 and CD44, but it has no effect on p53, BACH1 and CD44 in p53 mutant GBM cells. PELATON and p53 can form a complex through the RNA binding protein EIF4A3. Knockdown of PELATON resulted in smaller mitochondria, increased mitochondrial membrane density, and enhanced sensitivity to ferroptosis inducers to inhibit GBM cell proliferation and invasion. In addition, we established a favourite prognostic model with NCOA4 and PELATON. PELATON is a promising target for the prognosis and treatment of GBM.

Class I HDAC overexpression promotes temozolomide resistance in glioma cells by regulating RAD18 expression

Overexpression of histone deacetylases (HDACs) in cancer commonly causes resistance to genotoxic-based therapies. Here, we report on the novel mechanism whereby overexpressed class I HDACs increase the resistance of glioblastoma cells to the S_N1 methylating agent temozolomide (TMZ). The chemotherapeutic TMZ triggers the activation of the DNA damage response (DDR) in resistant glioma cells, leading to DNA lesion bypass and cellular survival. Mass spectrometry analysis revealed that the catalytic activity of class I HDACs stimulates the expression of the E3 ubiquitin ligase RAD18. Furthermore, the data showed that RAD18 is part of the O⁶-methylguanine-induced DDR as TMZ induces the formation of RAD18 foci at sites of DNA damage. Downregulation of RAD18 by HDAC inhibition prevented glioma cells from activating the DDR upon TMZ exposure. Lastly, RAD18 or O⁶-methylguanine-DNA methyltransferase (MGMT) overexpression abolished the sensitization effect of HDAC inhibition on TMZ-exposed glioma cells. Our study describes a mechanism whereby class I HDAC overexpression in glioma cells causes resistance to TMZ treatment. HDACs accomplish this by promoting the bypass of O⁶-methylguanine DNA lesions via enhancing RAD18 expression. It also provides a treatment option with HDAC inhibition to undermine this mechanism.

Use of glioma to assess the distribution patterns of perfluoroalkyl and polyfluoroalkyl substances in human brain

Human brain has a complex structure and is able to perform powerful functions. Blood-brain barrier blocks the entry of foreign substances and maintains the homeostasis of the brain. However, some exogenous substances are still able to pass through the blood-brain barrier, with distribution patterns yet to be clarified. Perfluoroalkyl and polyfluoroalkyl substances (PFASs), including perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs), a precursor (perfluorooctane sulfonamide that can be degraded to other substances), and emerging PFASs, were analyzed for the first time in living human brain glioma. The target compounds were detected and quantified in 25 out of 26 glioma samples. The concentration range of ∑PFAS was < RL-51 ng g^-1 wet weight (applied to all reported concentrations), with a median of 2.9 ng g^-1. The most abundant compound was PFCAs (40%), followed by PFSAs (28%), emerging PFASs (22%), and perfluorooctane sulfonamide (10%). Abundant alternatives PFASs, including short-chain PFCAs, short-chain PFSAs, and emerging PFASs (52% of ∑PFAS), were found in the glioma samples, supporting the notion that low molecular weight exogenous compounds have high permeability to cross the blood-brain barrier and accumulate in brain tissue. Gender difference was not significant (p > 0.05) in the concentrations of PFASs in the glioma samples. Concentrations of PFASs increased with increasing age, from 0.61 ng g^-1 (0-14 years old) to 1.6 ng g^-1 (>48 years old), with no significant linear correlation with age. The present study suggested that glioma is an effective indicator for monitoring exogenous contaminants in brain tissues.

Outcome of glioblastoma resection in patients 80 years of age and older

OBJECTIVE

To evaluate the role and possible complications of tumor resection in the management of glioblastoma (GBM) in a series of patients 80 years of age and older with review of literature.

METHODS

The authors retrospectively analyzed cases involving patients 80 years or older who underwent biopsy or initial resection of GBM at their hospital between 2007 and 2018. A total of 117 patients (mean age 82 years) met the inclusion criteria; 57 had resection (group A) and 60 had biopsy (group B). Functional outcomes and survival at follow-up were analyzed.

RESULTS

Group A differed significantly from group B at baseline in having better WHO performance status, better ASA scores, more right-sided tumors, and no basal ganglia or "butterfly" gliomas. Nevertheless, 56% of group A patients had an ASA score of 3. Median survival was 9.5 months (95% CI 8-17 months) in group A, 4 months (95% CI 3.5-6 months) in group B, and 17.5 months (95% CI 12-24 months) in the 56% of group A patients treated with resection and Stupp protocol. Rates of postoperative neurologic and medical complications were almost identical in the 2 groups, but the rate of surgical site complications was substantially greater in group A (12% vs 5%). There was no significant difference in mean preoperative and postoperative KPS scores (group A).

CONCLUSIONS

In selected patients 80 years or older, radical removal of GBM was associated with acceptable survival and a low perioperative complication rate which is comparable to that of a biopsy. Although the median survival of the whole group was lower than reported for younger patients, a subgroup amenable to radical surgery and Stupp protocol achieved a median survival of 17.5 months.

Strengthening Anti-Glioblastoma Effect by Multi-Branched Dendrimers Design of a Scorpion Venom Tetrapeptide

Glioblastoma is the most aggressive and invasive form of central nervous system tumors due to the complexity of the intracellular mechanisms and molecular alterations involved in its progression. Unfortunately, current therapies are unable to stop its neoplastic development. In this context, we previously identified and characterized AaTs-1, a tetrapeptide (IWKS) from Androctonus autralis scorpion venom, which displayed an anti-proliferative effect against U87 cells with an IC₅₀ value of 0.57 mM. This peptide affects the MAPK pathway, enhancing the expression of p53 and altering the cytosolic calcium concentration balance, likely via FPRL-1 receptor modulation. In this work, we designed and synthesized new dendrimers multi-branched molecules based on the sequence of AaTs-1 and showed that the di-branched (AaTs-1-2B), tetra-branched (AaTs-1-4B) and octo-branched (AaTs-1-8B) dendrimers displayed 10- to 25-fold higher effects on the proliferation of U87 cells than AaTs-1. We also found that the effects of the newly designed molecules are mediated by the enhancement of the ERK1/2 and AKT phosphorylated forms and by the increase in p53 expression. Unlike AaTs-1, AaTs-1-8B and especially AaTs-1-4B affected the migration of the U87 cells. Thus, the multi-branched peptide synthesis strategy allowed us to make molecules more active than the linear peptide against the proliferation of U87 glioblastoma cells.

Relationship between molecular characteristics of glioblastoma multiforme and the subventricular zone

OBJECTIVE

This study aims to assess the relationship between the molecular characteristics of glioblastoma multiforme (GBM) and the subventricular zone (SVZ).

MATERIAL AND METHODS

Eligible patients had their data anonymously collected from an institutional database, including age, sex, preoperative performance status, the extent of tumour resection, anatomical location, IDH mutation and MGMT methylation status. An Institutional picture archiving and communications system was used for volumetric and morphometric analysis. All measurements were made on T1-weighted magnetic resonance images with gadolinium contrast enhancement. IDH wild-type and mutant GBMs were stratified by MGMT methylation status. The relationship between tumour volume, distance from the tumour's enhancing edge and the tumour's geometric centre to the SVZ and their molecular characteristics were assessed.

RESULTS

Fifty IDH wild-type GBMs were studied. Twenty-three were MGMT methylated, Twenty-seven were unmethylated. IDH wild-type MGMT methylated GBMs were significantly associated with a tumour's enhancing boundary being contiguous to the SVZ (P < 0.001). Ninety percent of tumours contiguous to the SVZ were wild-type methylated (n = 18) and 10% were unmethylated (n = 2). Mean GBM geometric centre distance to SVZ was significantly less for methylated wild-type GBMs compared to unmethylated (P = 0.025) and median GBM distance from the tumour's edge of enhancement to the SVZ was significantly shorter in methylated tumours compared to unmethylated (P < 0.001). Mean and median distances to SVZ from the edge of enhancement was 3.8 millimetres (mm) and 0 mm, respectively, for wild-type methylated GBMs, while for unmethylated wild-types, 14.6 mm, and 12.5 mm. There was no anatomical localisation of IDH wild-type GBMs by MGMT methylation status to a cerebral hemisphere or lobe.

CONCLUSION

IDH wild-type GBMs contiguous to the SVZ are highly likely to be MGMT methylated. Replication by further studies is required to affirm our results and conclusion.

SPAG5 Is Involved in Human Gliomagenesis Through the Regulation of Cell Proliferation and Apoptosis

Background

Glioma is the most frequent malignant primary brain tumor in adults.

Objective

To explore the role of sperm-associated antigen 5 (SPAG5) in glioma.

Methods

The association between SPAG5 expression and clinical features was investigated based on The Cancer Genome Atlas (TCGA) datasets. The function of SPAG5 in glioma was analyzed using U87 and U251 cells. Knockdown glioma cells were constructed by shRNA interference. qRT-PCR and Western blotting were used to measure the expression of SPAG5 and Cadherin 2 (CDH2). Cell proliferation and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, caspase 3/7 assay, and high-content screening (HCS) proliferation analysis and colony formation assay. Transwell assays and wound-healing assays were used to investigate cell migration and invasion.

Results

The increased expression of SPAG5 was correlated with poor outcomes in glioma patients. Knocking down SPAG5 could inhibit the proliferation and colony formation and promoted the apoptosis of glioma cells. Knocking down SPAG5 could also inhibit cell migration and invasion and the expression of CDH2. Overexpression of CDH2 with SPAG5 depletion could restore the proliferation and inhibit the apoptosis of glioma cells, which also promoted cell migration and invasion.

Conclusions

SPAG5 is a promising prognostic factor and potential therapeutic target for clinical intervention in glioma.

Novel Concepts of Glioblastoma Therapy Concerning Its Heterogeneity

Although treatment outcomes of glioblastoma, the most malignant central nervous system (CNS) tumor, has improved in the past decades, it is still incurable, and survival has only slightly improved. Advances in molecular biology and genetics have completely transformed our understanding of glioblastoma. Multiple classifications and different diagnostic methods were made according to novel molecular markers. Discovering tumor heterogeneity only partially explains the ineffectiveness of current anti-proliferative therapies. Dynamic heterogeneity secures resistance to combined oncotherapy. As tumor growth proceeds, new therapy-resistant sub clones emerge. Liquid biopsy is a new and promising diagnostic tool that can step up with the dynamic genetic change. Getting a 'real-time' picture of a specific tumor, anti-invasion and multi-target treatment can be designed. During invasion to the peri-tumoral brain tissue, glioma cells interact with the extracellular matrix components. The expressional levels of these matrix molecules give a characteristic pattern, the invasion spectrum, which possess vast diagnostical, predictive and prognostic information. It is a huge leap forward combating tumor heterogeneity and searching for novel therapies. Using the invasion spectrum of a tumor sample is a novel tool to distinguish between histological subtypes, specifying the tumor grades or different prognostic groups. Moreover, new therapeutic methods and their combinations are under trial. These are crucial steps towards personalized oncotherapy.

Supratentorial Extraventricular Ependymomas: Imaging Features and the Added Value of Apparent Diffusion Coefficient

OBJECTIVE

To improve the understanding and the diagnosis of intracranial ependymal tumors.

METHODS

The clinical, radiological and prognostic features of 48 supratentorial extraventricular ependymomas and 74 intraventricular ependymomas were summarized and compared.

RESULTS

Supratentorial extraventricular ependymomas, most often located in the frontal lobe (33.3%) and classified as grade III (75.0%), had relatively large eccentric cysts (3.07 ± 2.03 cm), significant enhancement (84.8%), low apparent diffusion coefficient (ADC) values, and associated with higher mortality (41.3%). The majority of intraventricular lesions occurred in the fourth ventricle (86.5%) and classified as grade II (78.4%), had relatively small and multiple cystic changes (1.04 ± 0.87 cm), slight or moderate enhancement (76.9%), high ADC values and associated with lower mortality (20.7%). There were few significant differences between grade II and grade III tumors in these 2 groups, respectively. Young age, high grade and low ADC values are worse prognostic indicators for patients with supratentorial extraventricular ependymomas, but not for those with intraventricular ependymomas.

CONCLUSIONS

Conventional radiological features, combined with clinical manifestations and quantitative information provided by diffusion-weighted imaging, may not only enhance the diagnosis and assist in determining prognosis but also provide a better pathophysiological understanding of intracranial ependymal tumors.

Patient specific, imaging-informed modeling of rhenium-186 nanoliposome delivery via convection-enhanced delivery in glioblastoma multiforme

Convection-enhanced delivery of rhenium-186 (¹⁸⁶Re)-nanoliposomes is a promising approach to provide precise delivery of large localized doses of radiation for patients with recurrent glioblastoma multiforme. Current approaches for treatment planning utilizing convection-enhanced delivery are designed for small molecule drugs and not for larger particles such as¹⁸⁶Re-nanoliposomes. To enable the treatment planning for¹⁸⁶Re-nanoliposomes delivery, we have developed a computational fluid dynamics approach to predict the distribution of nanoliposomes for individual patients. In this work, we construct, calibrate, and validate a family of computational fluid dynamics models to predict the spatio-temporal distribution of¹⁸⁶Re-nanoliposomes within the brain, utilizing patient-specific pre-operative magnetic resonance imaging (MRI) to assign material properties for an advection-diffusion transport model. The model family is calibrated to single photon emission computed tomography (SPECT) images acquired during and after the infusion of¹⁸⁶Re-nanoliposomes for five patients enrolled in a Phase I/II trial (NCT Number NCT01906385), and is validated using a leave-one-out bootstrapping methodology for predicting the final distribution of the particles. After calibration, our models are capable of predicting the mid-delivery and final spatial distribution of¹⁸⁶Re-nanoliposomes with a Dice value of 0.69 ± 0.18 and a concordance correlation coefficient of 0.88 ± 0.12 (mean ± 95% confidence interval), using only the patient-specific, pre-operative MRI data, and calibrated model parameters from prior patients. These results demonstrate a proof-of-concept for a patient-specific modeling framework, which predicts the spatial distribution of nanoparticles. Further development of this approach could enable optimizing catheter placement for future studies employing convection-enhanced delivery.

IRDye800CW labeled uPAR-targeting peptide for fluorescence-guided glioblastoma surgery: Preclinical studies in orthotopic xenografts

Glioblastoma (GBM) is a devastating cancer with basically no curative treatment. Even with aggressive treatment, the median survival is disappointing 14 months. Surgery remains the key treatment and the postoperative survival is determined by the extent of resection. Unfortunately, the invasive growth with irregular infiltrating margins complicates an optimal surgical resection. Precise intraoperative tumor visualization is therefore highly needed and molecular targeted near-infrared (NIR) fluorescence imaging potentially constitutes such a tool. The urokinase-type Plasminogen Activator Receptor (uPAR) is expressed in most solid cancers primarily at the invading front and the adjacent activated peritumoral stroma making it an attractive target for targeted fluorescence imaging. The purpose of this study was to develop and evaluate a new uPAR-targeted optical probe, IRDye800CW-AE344, for fluorescence guided surgery (FGS).

Methods: In the present study we characterized the fluorescent probe with regard to binding affinity, optical properties, and plasma stability. Further, in vivo imaging characterization was performed in nude mice with orthotopic human patient derived glioblastoma xenografts, and we performed head-to-head comparison within FGS between our probe and the traditional procedure using 5-ALA. Finally, the blood-brain barrier (BBB) penetration was characterized in a 3D BBB spheroid model.

Results: The probe effectively visualized GBM in vivo with a tumor-to-background ratio (TBR) above 4.5 between 1 to 12 h post injection and could be used for FGS of orthotopic human glioblastoma xenografts in mice where it was superior to 5-ALA. The probe showed a favorable safety profile with no evidence of any acute toxicity. Finally, the 3D BBB model showed uptake of the probe into the spheroids indicating that the probe crosses the BBB.

Conclusion: IRDye800CW-AE344 is a promising uPAR-targeted optical probe for FGS and a candidate for translation into human use.

Nanotechnology for Cancer Imaging: Advances, Challenges, and Clinical Opportunities

Nanoparticle (NP) imaging applications have the potential to improve cancer diagnostics, therapeutics, and treatment management. In biomedical research and clinical practice, NPs can serve as labels or labeled carriers for monitoring drug delivery or serve as imaging agents for enhanced imaging contrast, as well as providing improved signal sensitivity and specificity for in vivo imaging of molecular and cellular processes. These qualities offer exciting opportunities for NP-based imaging agents to address current limitations in oncologic imaging. Despite substantial advancements in NP design and development, very few NP-based imaging agents have translated into clinics within the past 5 years. This review highlights some promising NP-enabled imaging techniques and their potential to address current clinical cancer imaging limitations. Although most examples provided herein are from the preclinical space, discussed imaging solutions could offer unique in vivo tools to solve biologic questions, improve cancer treatment effectiveness, and inspire clinical translation innovation to improve patient care. Keywords: Molecular Imaging-Cancer, Molecular Imaging-Nanoparticles, Molecular Imaging-Optical Imaging, Metastases, Oncology, Surgery, Treatment Effects.

PSMA Expression in Glioblastoma as a Basis for Theranostic Approaches: A Retrospective, Correlational Panel Study Including Immunohistochemistry, Clinical Parameters and PET Imaging

Aim

The aim of the current study was to enlighten the evolution of prostate-specific membrane antigen (PSMA) expression in glioblastoma between initial diagnosis and recurrence in order to provide preliminary insight for further clinical investigations into innovative PSMA-directed treatment concepts in neuro-oncology.

Methods

Patients who underwent resection for de-novo glioblastoma (GBM) and had a re-resection in case of a recurrent tumor following radiochemotherapy and subsequent chemotherapy were included (n = 16). Histological and immunohistochemical stainings were performed at initial diagnosis and at recurrence (n = 96 tissue specimens). Levels of PSMA expression both in endothelial and non-endothelial cells as well as vascular density (CD34) were quantified via immunohistochemistry and changes between initial diagnosis and recurrence were determined. Immunohistochemical findings were correlated with survival and established clinical parameters.

Results

PSMA expression was found to be present in all GBM tissue samples at initial diagnosis as well as in all but one case of recurrent tumor samples. The level of PSMA expression in glioblastoma varied inter-individually both in endothelial and non-endothelial cells. Likewise, the temporal evolution of PSMA expression highly varied in between patients. The level of vascular PSMA expression at recurrence and its change between initial diagnosis and recurrence was associated with post recurrence survival time: Patients with high vascular PSMA expression at recurrence as well as patients with increasing PSMA expression throughout the disease course survived shorter than patients with low vascular PSMA expression or decreasing vascular PSMA expression. There was no significant correlation of PSMA expression with MGMT promoter methylation status or Ki-67 labelling index.

Conclusion

PSMA is expressed in glioblastoma both at initial diagnosis and at recurrence. High vascular PSMA expression at recurrence seems to be a negative prognostic marker. Thus, PSMA expression in GBM might present a promising target for theranostic approaches in recurrent glioblastoma. Especially PSMA PET imaging and PSMA-directed radioligand therapy warrant further studies in brain tumor patients.

Therapeutic Delivery to Central Nervous System

Therapies for glioblastoma face several physiologic hurdles. The blood-brain barrier (BBB) and blood-brain-tumor barrier (BTB) present impediments to therapeutic delivery of drugs to the central nervous system. Strategies to disrupt or bypass the native BBB are necessary to deliver therapeutic agents. Techniques to bypass the BBB/BTB include implantable controlled-release polymer systems, intracavitary drug delivery, direct injection of viral vectors, and infusion via convection-enhanced delivery. Ideal methods and agents to accomplish the goal providing survival benefit are yet to be determined. Further development of methods to break down or bypass the BBB and BTB is necessary for patients with glioblastoma.

Advanced imaging techniques for neuro-oncologic tumor diagnosis, with an emphasis on PET-MRI imaging of malignant brain tumors

PURPOSE OF REVIEW

This review will explore the latest in advanced imaging techniques, with a focus on the complementary nature of multiparametric, multimodality imaging using magnetic resonance imaging (MRI) and positron emission tomography (PET).

RECENT FINDINGS

Advanced MRI techniques including perfusion-weighted imaging (PWI), MR spectroscopy (MRS), diffusion-weighted imaging (DWI), and MR chemical exchange saturation transfer (CEST) offer significant advantages over conventional MR imaging when evaluating tumor extent, predicting grade, and assessing treatment response. PET performed in addition to advanced MRI provides complementary information regarding tumor metabolic properties, particularly when performed simultaneously. 18F-fluoroethyltyrosine (FET) PET improves the specificity of tumor diagnosis and evaluation of post-treatment changes. Incorporation of radiogenomics and machine learning methods further improve advanced imaging. The complementary nature of combining advanced imaging techniques across modalities for brain tumor imaging and incorporating technologies such as radiogenomics has the potential to reshape the landscape in neuro-oncology.

Kinesin Family Member C1 Increases Temozolomide Resistance of Glioblastoma Through Promoting DNA Damage Repair

Glioblastoma (GBM) is one of the most frequent primary malignant brain tumors with a poor prognosis. Unfortunately, due to the intrinsic or acquired chemoresistance of GBM cells, it easily becomes refractory disease and tumors are easy to recur. Therefore, it is critical to elucidate the molecular mechanisms underlying the chemoresistance of GBM cells to discover more efficient therapeutic treatments. Kinesin family member C1 (KIFC1) is a normal nonessential kinesin motor that affects the progression of multiple types of cancers. However, whether KIFC1 have a function in GBM is still unexplored. Here we found that KIFC1 was upregulated in human temozolomide (TMZ)-resistant GBM tissues. KIFC1 silencing is sufficient to inhibit GBM cell proliferation and amplify TMZ-induced repression of cell proliferation. Mechanistically, KIFC1 silencing contributed to DNA damage, cell cycle arrest, and apoptosis through regulating Rad51, Akt, and DNA-PKcs phosphorylation. We also noticed that KIFC1 silencing also inhibited tumor formation and increased TMZ sensitivity through regulating Ki67, Rad51, γ-H2AX, and phosphorylation of AKT in vivo. Our findings therefore confirm the involvement of KIFC1 in GBM progression and provide a novel understanding of KIFC1-Akt axis in the sensitivity of GBM to chemotherapy.

A Hematological-Related Prognostic Scoring System for Patients With Newly Diagnosed Glioblastoma

Background

Glioblastoma is the most common primary malignant brain tumor. Recent studies have shown that hematological biomarkers have become a powerful tool for predicting the prognosis of patients with cancer. However, most studies have only investigated the prognostic value of unilateral hematological markers. Therefore, we aimed to establish a comprehensive prognostic scoring system containing hematological markers to improve the prognostic prediction in patients with glioblastoma.

Patients and Methods

A total of 326 patients with glioblastoma were randomly divided into a training set and external validation set to develop and validate a hematological-related prognostic scoring system (HRPSS). The least absolute shrinkage and selection operator Cox proportional hazards regression analysis was used to determine the optimal covariates that constructed the scoring system. Furthermore, a quantitative survival-predicting nomogram was constructed based on the hematological risk score (HRS) derived from the HRPSS. The results of the nomogram were validated using bootstrap resampling and the external validation set. Finally, we further explored the relationship between the HRS and clinical prognostic factors.

Results

The optimal cutoff value for the HRS was 0.839. The patients were successfully classified into different prognostic groups based on their HRSs (P < 0.001). The areas under the curve (AUCs) of the HRS were 0.67, 0.73, and 0.78 at 0.5, 1, and 2 years, respectively. Additionally, the 0.5-, 1-y, and 2-y AUCs of the HRS were 0.51, 0.70, and 0.79, respectively, which validated the robust prognostic performance of the HRS in the external validation set. Based on both univariate and multivariate analyses, the HRS possessed a strong ability to predict overall survival in both the training set and validation set. The nomogram based on the HRS displayed good discrimination with a C-index of 0.81 and good calibration. In the validation cohort, a high C-index value of 0.82 could still be achieved. In all the data, the HRS showed specific correlations with age, first presenting symptoms, isocitrate dehydrogenase mutation status and tumor location, and successfully stratified them into different risk subgroups.

Conclusions

The HRPSS is a powerful tool for accurate prognostic prediction in patients with newly diagnosed glioblastoma.

Deficiency of G9a Inhibits Cell Proliferation and Activates Autophagy via Transcriptionally Regulating c-Myc Expression in Glioblastoma

Glioblastoma is an aggressive and difficult to treat cancer. Recent data have emerged implicating that histone modification level may play a crucial role in glioma genesis. The histone lysine methyltransferase G9a is mainly responsible for the mono- and di-methylation of histone H3 lysine 9 (H3K9), whose overexpression is associated with a more aggressive phenotype in cancer. However, the detailed correlations between G9a and glioblastoma genesis remain to be further elucidated. Here, we show that G9a is essential for glioblastoma carcinogenesis and reveal a probable mechanism of it in cell proliferation control. We found that G9a was highly expressed in glioblastoma cells, and knockdown or inhibition of G9a significantly repressed cell proliferation and tumorigenesis ability both in vitro and in vivo. Besides, knockdown or inhibition of G9a led to a cell cycle arrest in G2 phase, as well as decreased the expression of CDK1, CDK2, Cyclin A2, and Cyclin B1, while it induced the activation of autophagy. Further investigation showed that G9a deficiency induced cell proliferation suppression, and activation of autophagy was rescued by overexpression of the full-length c-Myc. Chromatin immunoprecipitation (ChIP) assay showed that G9a was enriched on the −2267 to −1949 region of the c-Myc promoter in LN-229 cells and the −1949 to −1630 region of the c-Myc promoter in U-87 MG cells. Dual-luciferase reporter assay showed that c-Myc promoter activity was significantly reduced after knockdown or inhibition of G9a. Our study shows that G9a controls glioblastoma cell proliferation by transcriptionally modulating oncogene c-Myc and provides insight into the capabilities of G9a working as a potential therapeutic target in glioblastoma.