Angiogenesis in brain tumours

Tertiary lymphoid structures achieve 'cold' to 'hot' transition by remodeling the cold tumor microenvironment

Immune checkpoint blockade (ICB) therapies have demonstrated significant clinical efficacy in immune-infiltrated tumors such as melanoma and non-small cell lung cancer. However, "cold tumors"-including ovarian cancer, pancreatic cancer, and gliomas-exhibit insufficient immune infiltration, leading to poor therapeutic responses to ICBs and limited improvement in patient prognosis. Recent studies have shown that tumor-associated tertiary lymphoid structures (TLSs) can induce strong local immune responses within the tumor microenvironment (TME), serving as important biological markers for predicting ICB therapy efficacy. Notably, preclinical and clinical studies on cold tumors have confirmed that TLSs can potently enhance ICB efficacy through TME remodeling-a breakthrough that has attracted considerable attention. Here, we systematically examine the immunological profile of cold tumors and decipher the mechanistic basis for their impaired immune cell infiltration. We further delineate the distinctive features of tumor-associated TLSs in generating antitumor immunity and establish criteria for their identification. Significantly, we emphasize the unique capability of TLSs to reprogram the immunosuppressive tumor microenvironment characteristic of cold tumors. Based on these insights, we evaluate clinical evidence supporting TLS-mediated enhancement of ICB efficacy and discuss emerging strategies for exogenous TLSs induction.

Blood-oxygenation-level-dependent (BOLD) MRI responses to CO2 and O2 inhalation in brain gliomas

PURPOSE

Cerebrovascular abnormalities are intricately involved in gliomas. While static cerebrovascular properties such as cerebral blood flow, volume, and permeability have been extensively studied, dynamic vascular parameters have not been fully understood. This study aimed to characterize the vascular responses to CO2 and O2 inhalation in brain gliomas.

METHODS

In 15 glioma patients, concomitant CO2 and O2 inhalation was applied while BOLD MR images were continuously acquired for nine minutes, resulting in the measurement of O2-reactivity, CO2-reactivity, and bolus arrival time (BAT). Vascular parameters were compared between the tumor regions and contralateral healthy tissue using Student t-tests. The dependence of vascular parameters on glioma grade, glioma subtypes, and molecular biomarkers were assessed using a multiple linear regression.

RESULTS

Visual inspection suggested that reliable O2-reactivity, CO2-reactivity, and BAT maps could be obtained in every patient. Compared to the contralateral healthy tissue, glioma regions on average revealed a diminished O2-reactivity (p < 0.001) and CO2-reactivity (p < 0.001), but a lengthened BAT (p < 0.001). Intra-tumoral heterogeneity in the vascular parameters between core and periphery was also observed. Astrocytomas had a lower CO2-reactivity (p = 0.014) and a longer BAT (p = 0.012) relative to oligodendrogliomas. Glioma grade had no association with O2-reactivity, CO2-reactivity, or BAT. Patients who lost ATRX expression had a lower CO2- and O2-reactivity (p = 0.005 and p = 0.035) compared to patients who retained ATRX expression.

CONCLUSIONS

Gliomas are associated with abnormal CO2- and O2-reactivity measured with MRI. These dynamic parameters may provide new insights into the vascular pathophysiology in gliomas.

Immune cell infiltration into brain tumor microenvironment is mediated by Rab27-regulated vascular wall integrity

Aggressive brain tumors often exhibit immunologically 'cold' microenvironment, where the vascular barrier impedes effective immunotherapy in poorly understood ways. Tumor vasculature also plays a pivotal role in immunoregulation and antitumor immunity. Here, we show that small GTPase Rab27 controls the vascular morphogenesis and permeability for blood content and immune effectors. Thus, in Rab27a/b double knock out (Rab27-dKO) mice, the brain vasculature is abnormally scarce, while the blood vessels become dysmorphic and hyperpermeable in the context of brain tumors, including syngeneic glioblastoma. These defects are reflected in rearrangements of endothelial cell subpopulations with underlying diminution of venous endothelial subtype along with changes in gene and protein expression. Notably, Rab27-dKO brain endothelial cells exhibit deficient tight junctions, whereby they enable large-scale extravasation of cytotoxic T cells into the tumor mass. We show that Rab27-regulated vascular T cell infiltration can be exploited to enhance adoptive T cell therapy in syngeneic brain tumors.

Intraoperative superb microvascular ultrasound imaging in glioma: novel quantitative analysis correlates with tumour grade

BACKGROUND

Accurate grading of gliomas is critical to guide therapy and predict prognosis. The presence of microvascular proliferation is a hallmark feature of high grade gliomas which to directly visualise traditionally requires targeted surgical biopsy of representative tissue. Superb microvascular imaging (SMI) is a novel high resolution Doppler ultrasound technique which can uniquely define the microvascular architecture of whole tumours.

METHODS

We examined both qualitative and quantitative vascular features of 32 gliomas captured with SMI, analysing flow signal density, vessel number, branching points, curvature, vessel angle deviation, fractal dimension, and entropy.

RESULTS

High-grade gliomas exhibit significantly greater vascular complexity and disorganisation, with increased fractal dimension and entropy, correlating with known histopathological markers of aggressive angiogenesis. The integrated ROC model achieved high accuracy (AUC = 0.95).

CONCLUSIONS

This study leveraged SMI to provide further insights into the microvascular architecture of gliomas which is not resolvable by magnetic resonance imaging. Applying novel quantitative analysis the study demonstrated that there are quantifiable differences in vascular morphology between high grade and low-grade gliomas. This unique in vivo imaging of glioma vascularity and quantification warrants further exploration as a potential new diagnostic and prognostic tool that may support glioma management, intraoperative decision-making and informing future prognosis.

A Positive Feedback DNA-PK/MYT1L-CXCR1-ERK1/2 Proliferative Signaling Loop in Glioblastoma

Glioblastoma is the most common primary brain tumor in adults. Our previous studies revealed a functional interplay of myelin transcription factor 1-like (MYT1L) with the DNA-dependent protein kinase (DNA-PK) in the regulation of p21 transcription. However, the contributing role of this functional interplay in glioblastoma remains largely unknown. Here, we used cell lines with normal DNA-PK (HEK293 and M059K) or deficient DNA-PK (M059J) as a model system to demonstrate the importance of the DNA-PK-dependent activation of MYT1L in controlling the transcription of CXC chemokine receptor 1 (CXCR1) in a positive-feedback proliferative signaling loop in glioblastoma with numerous conventional techniques. In normal DNA-PK cells, MYT1L acted as an oncogene by promoting cell proliferation, inhibiting apoptosis, and shortening a cell cycle S phase. However, in DNA-PK-deficient cells, MYT1L functioned as a tumor suppressor by inhibiting cell proliferation and inducing a G1 arrest. The enforced expression of MYT1L promoted CXCR1 transcription in DNA-PK-normal cells but attenuated transcription in DNA-PK-deficient cells. Bioinformatics analysis predicted a MYT1L-binding sequence at the CXCR1 promoter. The functional dependence of MYT1L on DNA-PK in CXCR1 transcription was validated by luciferase assay. Although the expression of CXCR1 was lower in M059J cells as compared to M059K cells, it was higher than in normal brain tissue. The CXCR1 ligands interleukin 8 (IL-8) and GRO protein alpha (GROα) expressed in M059J and M059K cells may signal through the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway that can be blocked by CXCR1 siRNA. Our findings demonstrate the existence of a positive feedback DNA-PK/MYT1L-CXCR1-ERK1/2 proliferation loop in glioblastoma cells that may represent a pharmacological target loop for therapeutic intervention.

Glioblastoma targeting by water-soluble hypericin derivate HHL-PVP and photodynamic tumour killing

Hypericin, a tumour-selective photosensitizer, has shown potential in cancer therapy, but its poor water solubility has limited clinical use. To address this, we developed a water-soluble variant called high hypericin-loaded polyvinylpyrrolidone (HHL-PVP) to enhance hypericin's applicability, particularly for treating glioblastoma, a typically terminal disease. We tested HHL-PVP in both in vitro and in vivo models, first confirming its fluorescent properties in the lab and then assessing its efficacy in more complex animal models. Using subcutaneous and orthotopic tumour mouse models, we combined HHL-PVP administration with fluorescence-guided surgery and photodynamic therapy (PDT) to target residual tumour cells. Histological analysis of both healthy and tumour tissue showed HHL-PVP's over 97 % sensitivity and 100 % specificity in distinguishing tumour tissue. In subcutaneous glioblastoma models, significant tumour necrosis and remission occurred after HHL-PVP administration and a 20-minute white light application through the skin. These results highlight HHL-PVP's effectiveness in targeting and eradicating glioblastoma cells. Our findings provide strong evidence that HHL-PVP is a promising therapeutic option for glioblastoma, with its high sensitivity, specificity, and potential for tumour remission through PDT. This approach warrants further investigation in clinical trials and could improve outcomes for a disease that has been difficult to treat.

Noninvasive blood-brain barrier integrity mapping in patients with high-grade glioma and metastasis by multi-echo time-encoded arterial spin labeling

PURPOSE

In brain tumors, disruption of the blood-brain barrier (BBB) indicates malignancy. Clinical assessment is qualitative; quantitative evaluation is feasible using the K2 leakage parameter from dynamic susceptibility contrast MRI. However, contrast agent-based techniques are limited in patients with renal dysfunction and insensitive to subtle impairments. Assessing water transport times across the BBB (Tex) by multi-echo arterial spin labeling promises to detect BBB impairments noninvasively and potentially more sensitively. We hypothesized that reduced Tex indicates impaired BBB. Furthermore, we assumed higher sensitivity for Tex than dynamic susceptibility contrast-based K2, because arterial spin labeling uses water as a freely diffusible tracer.

METHODS

We acquired 3T MRI data from 28 patients with intraparenchymal brain tumors (World Health Organization Grade 3 & 4 gliomas [n = 17] or metastases [n = 11]) and 17 age-matched healthy controls. The protocol included multi-echo and single-echo Hadamard-encoded arterial spin labeling, dynamic susceptibility contrast, and conventional clinical imaging. Tex was calculated using a T2-dependent multi-compartment model. Areas of contrast-enhancing tissue, edema, and normal-appearing tissue were automatically segmented, and parameter values were compared across volumes of interest and between patients and healthy controls.

RESULTS

Tex was significantly reduced (-20.3%) in contrast-enhancing tissue compared with normal-appearing gray matter and correlated well with |K2| (r = -0.347). Compared with healthy controls, Tex was significantly lower in tumor patients' normal-appearing gray matter (Tex,tumor = 0.141 ± 0.032 s vs. Tex,HC = 0.172 ± 0.036 s) and normal-appearing white matter (Tex,tumor = 0.116 ± 0.015 vs. Tex,HC = 0.127 ± 0.017 s), whereas |K2| did not differ significantly. Receiver operating characteristic analysis showed a larger area under the curve for Tex (0.784) than K2 (0.604).

CONCLUSION

Tex is sensitive to pathophysiologically impaired BBB. It agrees with contrast agent-based K2 in contrast-enhancing tissue and indicates sensitivity to subtle leakage.

Advances in stem cell-based therapeutic transfers for glioblastoma treatment

INTRODUCTION

Glioblastoma (GBM), a highly malignant brain tumor, has a poor prognosis despite standard treatments like surgery, chemotherapy, and radiation. Glioblastoma stem cells (GSCs) play a critical role in recurrence and therapy resistance. Stem cell-based therapies have emerged as innovative approaches, leveraging the tumor-targeting abilities of stem cells to deliver treatments directly to GBM.

AREAS COVERED

This review focuses on using intact stem cells or subtypes for GBM therapy, excluding antigenic characteristics. The stem cell-based therapies explored include neural, mesenchymal, glioblastoma, hematopoietic and adipose-derived stem cells that have been investigated in both clinical and preclinical settings. A systematic search in PubMed, EMBASE, ClinicalTrials.gov, and Scopus had identified research up until January 2024. Key mechanisms reviewed include immune modulation, angiogenesis inhibition, and apoptosis induction. Discussion of completed and ongoing trials include emphasis on safety, efficacy, challenges, and study design limitations.

EXPERT OPINION

Stem cell-based therapies hold promise for treating GBM by targeting GSCs and improving treatment outcomes. Despite some potential advantages, challenges such as tumorigenesis risks, delivery complexities, and sustained therapeutic effects persist. Future research should prioritize optimizing stem cell modifications, combining them with current treatments, and conducting large-scale trials to ensure safety and efficacy. Integrating stem cell therapies into GBM treatment could provide more effective and less invasive options for patients.

Multi-transcriptomics reveals niche-specific expression programs and endothelial cells in glioblastoma

BACKGROUND

Glioblastoma (GBM) is a highly lethal malignant intracranial tumor, distinguished from low-grade glioma by histopathological hallmarks such as pseudopalisading cells around necrosis (PAN) and microvascular proliferation (MVP). To date the spatial organization of the molecular and cellular components of these specific histopathological features has not been fully elucidated.

METHODS

Here, using bulk RNA sequencing, spatial transcriptomic and single cell RNA sequencing (scRNA-seq) data of GBM patients, we identified niche-specific transcriptional programs and characterized the differences in molecular expression and cellular organization between PAN and MVP.

RESULTS

Notably, we discovered spatially distinct domains within the tumor core and identified niche-specific signatures: NDRG1 and EPAS1, specifically expressed in the PAN and MVP regions. The clustering results showed two distinct phenotypes of endothelial cells (ECs) were enriched in the MVP and PAN regions, respectively. PAN-associated endothelial cells exhibit copy number variations similar to those in GBM cells. Single cell trajectory analysis reveals a pseudotime trajectory, indicating the differentiation of glioblastoma stem cells (GSCs) toward ECs.

CONCLUSIONS

Necrosis cores which are surrounded by hypoxic and perivascular niches and microvascular proliferation area within the glioblastoma tumor microenvironment, have been considered as standardized morphological indicators of aggressive GBM. Our findings provide a cellular and molecular insights into GBM progression.

Roles of selenium-containing glutathione peroxidases and thioredoxin reductases in the regulation of processes associated with glioblastoma progression

Glioblastoma remains the most common and aggressive primary tumor of the central nervous system in adults. Current treatment options include standard surgical resection combined with radiation/chemotherapy, but such protocol most likely only delays the inevitable. Therefore, the problem of finding therapeutic targets to prevent the occurrence and development of this severe oncological disease is currently acute. It is known that the functions of selenoproteins in the regulation of carcinogenesis processes are not unambiguous. Either they exhibit cytotoxic activity on cancer cells, or cytoprotective. A special place in the progression of oncological diseases of various etiologies is occupied by proteins of the thioredoxin and glutathione systems. These are two cellular antioxidant systems that regulate redox homeostasis, counteracting the increased production of reactive oxygen species in cells. The review reflects the latest data on the role of key enzymes of these redox systems in the regulation of processes associated with the progression of glioblastoma. A thorough consideration of these issues will expand fundamental knowledge about the functions of selenium-containing thioredoxin reductases and glutathione peroxidases in the therapy of glioblastomas and provide an understanding of the prospects for the treatment of this aggressive oncological disease.

Adenoid glioblastoma: Stromal hypovascularity and secretion of chondromodulin-I by tumor cells

The case of a 75-year-old man with a glioblastoma of the right frontal lobe showing features of adenoid glioblastoma is reported. The tumor consisted of two components: the adenoid component, in which large, cohesive, polygonal cells with vesicular nuclei and abundant basophilic cytoplasm showed nest-like, trabecular, or tubular growth on the myxoid matrix and formed a multinodular configuration; and the subsidiary component, in which short spindle cells showed compact fascicular growth. The features of ordinary glioblastoma were also found in a small area. Tumor cells were immunoreactive for S-100 protein, glial fibrillary acidic protein, and Olig2, and some tumor cells in the adenoid component showed immunoreactivity for cytokeratins and E-cadherin. A marked regional decrease in microvascular density, approaching almost complete absence of microvessels, was demonstrated in the adenoid component. In contrast, microvascular density was well preserved in the spindle cell component and the area of ordinary glioblastoma. Tumor cells in the adenoid component showed cytoplasmic expression of chondromodulin-I, one of the cytokines that strongly inhibit angiogenesis, whereas the expression of this protein was very weak or only faint in the spindle cell component and the area of ordinary glioblastoma. A marked regional decrease in microvascular density was associated with myxoid change of the stroma and considered to be caused by the secretion of chondromodulin-I by tumor cells. Stromal hypovascularity with myxoid change might play an important role in the morphogenesis of adenoid features.

LncRNA BDNF-AS binds to DNMT1 to suppress angiogenesis in glioma by promoting NEDD4L-mediated YAP1 ubiquitination

Glioma, a highly aggressive brain tumor, is characterized by high mortality and frequent recurrence rates. Angiogenesis is a critical hallmark of glioma progression. However, the regulatory role and underlying mechanism of lncRNA brain-derived neurotrophic factor-antisense (BDNF-AS) in glioma angiogenesis remain poorly understood and warrant further investigation. Malignant characteristics of glioma cells were evaluated using CCK-8, colony formation, scratch, transwell, flow cytometry, and tube formation assays. The expression levels of genes and proteins were detected by RT-qPCR, western blot, and IHC assays. The methylation level of NEDD4-like E3 ubiquitin protein ligase (NEDD4L) was determined using MSP. The interactions among molecules were validated using RIP, ChIP, and Co-IP. Our study revealed significantly downregulated BDNF-AS expression in glioma cells. BDNF-AS overexpression markedly attenuated the malignant characteristics of glioma cells, as evidenced by decreased viability, proliferation, migration, invasion, and angiogenesis, along with increased apoptosis. These tumor-suppressive effects were significantly abrogated by NEDD4L knockdown. Mechanistically, BDNF-AS could interact with DNA methyltransferase 1 (DNMT1) expression, leading to reduced NEDD4L promoter methylation and upregulation of NEDD4L expression. Additionally, NEDD4L-mediated promotion of YAP1 ubiquitination to decline YAP1 and VEGFA expression. Finally, BDNF-AS exerted potent anti-tumor effects by mediating NEDD4L/YAP1/VEGFA axis, as demonstrated by suppressed tumor growth in glioma-bearing mice and attenuated malignant features in glioma cells. BDNF-AS suppressed cell viability, proliferation, migration, and invasion, and promoted cell apoptosis of glioma cells, attenuated angiogenesis of human umbilical vein endothelial cells (HUVECs), and tumor growth via regulating NEDD4L/YAP1/VEGFA axis.

Hunting glioblastoma recurrence: glioma stem cells as retrospective targets

Glioblastoma (GBM) remains one of the most aggressive and treatment-resistant brain malignancies in adults. Standard approaches, including surgical resection followed by adjuvant radio- and chemotherapy with temozolomide (TMZ), provide only transient control, as GBM frequently recurs due to its infiltrative nature and the presence of therapy-resistant subpopulations such as glioma stem cells (GSCs). GSCs, with their quiescent state and robust resistance mechanisms, evade conventional therapies, contributing significantly to relapse. Consequently, current treatment methods for GBM face significant limitations in effectively targeting GSCs. In this review, we emphasize the relationship between GBM recurrence and GSCs, discuss the current limitations, and provide future perspectives to overwhelm the challenges associated with targeting GSCs. Eliminating GSCs may suppress recurrence, achieve durable responses, and improve therapeutic outcomes for patients with GBM.

Modulating the blood-brain barrier in CNS disorders: A review of the therapeutic implications of secreted protein acidic and rich in cysteine (SPARC)

Secreted protein acidic and rich in cysteine (SPARC), an essential stromal cell protein, plays a crucial role in angiogenesis and maintaining endothelial barrier function. This protein is expressed by diverse cell types, including endothelial cells, fibroblasts, and macrophages, with increased expression found in regions of tissues undergoing active remodeling, repair, and proliferation. The role of SPARC in non-neural tissues is of significant interest. In the central nervous system (CNS), SPARC is highly expressed in blood vessels during early development. It becomes down-regulated as the brain matures, a pattern consistent with its role in angiogenesis and blood-brain barrier (BBB) establishment. In this review, we explore the multifaceted roles of SPARC in regulating CNS disorders, particularly its action in angiogenesis, inflammatory responses, neural system development and repair, barrier establishment, maintenance of BBB function, and the pathogenesis of CNS disorders triggered by BBB dysfunction.

Bridging the gap between tumor and disease: Innovating cancer and glioma models

Recent advances in cancer biology and therapeutics have underscored the importance of preclinical models in understanding and treating cancer. Nevertheless, current models often fail to capture the complexity and patient-specific nature of human tumors, particularly gliomas. This review examines the strengths and weaknesses of such models, highlighting the need for a new generation of models. Emphasizing the critical role of the tumor microenvironment, tumor, and patient heterogeneity, we propose integrating our advanced understanding of glioma biology with innovative bioengineering and AI technologies to create more clinically relevant, patient-specific models. These innovations are essential for improving therapeutic development and patient outcomes.

Revolutionizing Cancer Treatment: Harnessing the Power of Mesenchymal Stem Cells for Precise Targeted Therapy in the Tumor Microenvironment

In recent years, mesenchymal stem cells (MSCs) have emerged as promising anti-- cancer mediators with the potential to treat several cancers. MSCs have been modified to produce anti-proliferative, pro-apoptotic, and anti-angiogenic molecules that could be effective against a variety of malignancies. Additionally, customizing MSCs with cytokines that stimulate pro-tumorigenic immunity or using them as vehicles for traditional chemical molecules with anti-cancer characteristics. Even though the specific function of MSCs in tumors is still challenged, promising outcomes from preclinical investigations of MSC-based gene therapy for a variety of cancers inspire the beginning of clinical trials. In addition, the tumor microenvironment (TME) could have a substantial influence on normal tissue stem cells, which can affect the treatment outcomes. To overcome the complications of TME in cancer development, MSCs could provide some signs of hope for converting TME into unequivocal therapeutic tools. Hence, this review focuses on engineered MSCs (En-MSCs) as a promising approach to overcoming the complications of TME.

Design and in silico analysis of a novel peptide-based multiepitope vaccine against glioblastoma multiforme by targeting tumor-associated macrophage

CD204 is a distinct indicator for tumor-associated macrophages (TAMs) in glioma. Evidence indicates that CD204-positive TAMs are involved in the aggressive behavior of various types of cancers. This study was conducted to develop a new and effective peptide-based vaccine for GBM, specifically targeting CD204. Epitopes of the target protein were identified using NetMHCpan 4.1a, NetMHCIIpan-4.0, and ABCpred tools. Subsequently, the predicted epitopes were evaluated using bioinformatics tools to assess their antigenicity, non-allergenicity, immunogenicity, non-toxicity, and potential to stimulate the production of IL-4 and IFN-γ in HTL epitopes. Selected T-cell epitopes demonstrated a robust binding affinity with the particular HLA alleles. Finally, four HTL epitopes, three CTL epitopes, and two B-cell epitopes, jointed via linkers and adjuvant, were used for the final vaccine construct design. Analysis disclosed that the developed vaccine demonstrated robust antigenic properties while proving soluble, stable, non-toxic, and non-allergenic. Additionally, molecular docking studies and molecular dynamics simulations confirmed a robust correlation between the designed vaccine and TLR-2 and TLR-4 immune receptors. The molecular docking results demonstrated a strong interaction between the newly developed vaccine and TLR2 (-895.1 kcal/mol) and TLR4 (-881.0 kcal/mol) receptors. During the simulation, the vaccine-TLR2 and vaccine-TLR4 complexes exhibited binding energies of -113.41 and -106.61 kcal/mol, respectively. Analysis by different bioinformatic tools indicated the potential of the designed vaccine in immune stimulation and a significant elevation in IgG and IgM antibodies, T-helper cells, T-cytotoxic cells, INF-γ, IL-2, and IL-4. Research findings show that the newly designed multi-epitope vaccine is promising in providing long-term immunity against GBM and offers a promising therapeutic alternative.

Regorafenib Treatment for Recurrent Glioblastoma Beyond Bevacizumab-Based Therapy: A Large, Multicenter, Real-Life Study

BACKGROUND/OBJECTIVES

In the REGOMA trial, regorafenib demonstrated an overall survival advantage over lomustine, and it has become a recommended treatment for recurrent glioblastoma in guidelines. This study aimed to evaluate the effectiveness and safety of regorafenib as a third-line treatment for patients with recurrent glioblastoma who progressed while taking bevacizumab-based therapy.

METHODS

This retrospective, multicenter study in Turkey included 65 patients treated between 2021 and 2023 across 19 oncology centers. The main inclusion criteria were histologically confirmed isocitrate dehydrogenase (IDH)-wildtype glioblastoma, progression after second-line bevacizumab-based treatment, and an Eastern Cooperative Oncology Group (ECOG) performance status score of ≤2. Patients received regorafenib 160 mg once daily for the first 3 weeks of each 4-week cycle.

RESULTS

The median age of the patients was 53 years (18-67 years), with a median progression-free survival of 2.5 months (95% Confidence Interval: 2.23-2.75) and a median overall survival of 4.1 months (95% CI: 3.52-4.68). The median overall survival was improved in patients who received subsequent therapy after regorafenib treatment compared with those who did not (p = 0.022). Progression-free survival was longer in patients with ECOG 0-1 than in those with ECOG 2 (p = 0.042). The safety profile was consistent with that of the REGOMA trial, with no drug-related deaths observed.

CONCLUSIONS

Regorafenib shows good efficacy and safety as a third-line treatment for recurrent glioblastoma after bevacizumab-based therapy. This study supports the use of regorafenib and emphasizes the need for further randomized studies to validate its role and optimize treatment strategies.

Intraoperative superb microvascular ultrasound imaging in glioma: novel quantitative analysis correlates with tumour grade

Accurate grading of gliomas is critical to guide therapy and predict prognosis. The presence of microvascular proliferation is a hallmark feature of high grade gliomas which traditionally requires targeted surgical biopsy of representative tissue. Superb microvascular imaging (SMI) is a novel high resolution Doppler ultrasound technique which can uniquely define the microvascular architecture of whole tumours. We examined both qualitative and quantitative vascular features of gliomas captured with SMI, analysing flow signal density, vessel number, branching points, curvature, vessel angle deviation, fractal dimension, and entropy. Results indicate that high-grade gliomas exhibit significantly greater vascular complexity and disorganisation, with increased fractal dimension and entropy, correlating with known histopathological markers of aggressive angiogenesis. The integrated ROC model achieved high accuracy (AUC = 0.95), highlighting SMI's potential as a non-invasive diagnostic and prognostic tool. While further validation with larger datasets is required, this study opens avenues for SMI in glioma management, supporting intraoperative decision-making and informing future prognosis.

Hybrid-integrated devices for mimicking malignant brain tumors ("tumor-on-a-chip") for in vitro development of targeted drug delivery and personalized therapy approaches

Acute and requiring attention problem of oncotheranostics is a necessity for the urgent development of operative and precise diagnostics methods, followed by efficient therapy, to significantly reduce disability and mortality of citizens. A perspective way to achieve efficient personalized treatment is to use methods for operative evaluation of the individual drug load, properties of specific tumors and the effectiveness of selected therapy, and other actual features of pathology. Among the vast diversity of tumor types-brain tumors are the most invasive and malignant in humans with poor survival after diagnosis. Among brain tumors glioblastoma shows exceptionally high mortality. More studies are urgently needed to understand the risk factors and improve therapy approaches. One of the actively developing approaches is the tumor-on-a-chip (ToC) concept. This review examines the achievements of recent years in the field of ToC system developments. The basics of microfluidic chips technologies are considered in the context of their applications in solving oncological problems. Then the basic principles of tumors cultivation are considered to evaluate the main challengers in implementation of microfluidic devices, for growing cell cultures and possibilities of their treatment and observation. The main achievements in the culture types diversity approaches and their advantages are being analyzed. The modeling of angiogenesis and blood-brain barrier (BBB) on a chip, being a principally important elements of the life system, were considered in detail. The most interesting examples and achievements in the field of tumor-on-a-chip developments have been presented.

MicroRNA-382 as a tumor suppressor during tumor progression

Despite the recent progresses in therapeutic and diagnostic methods, there is still a significantly high rate of mortality among cancer patients. One of the main reasons for the high mortality rate in cancer patients is late diagnosis, which leads to the failure of therapeutic strategies. Therefore, investigation of cancer biology can lead to the introduction of early diagnostic markers in these patients. MicroRNAs (miRNAs) play an important role in regulation of cellular processes associated with tumor progression. Due to the high stability of miRNAs in body fluids, these factors can be considered as the non-invasive tumor markers. Deregulation of miR-382 has been widely reported in different cancers. Therefore, in this review, we investigated the role of miR-382 during tumor development. It has shown that miR-382 has mainly a tumor suppressive, which inhibits the growth of tumor cells through the regulation of signaling pathways, RNA-binding proteins, and transcription factors. Therefore, miR-382 can be suggested as a diagnostic and therapeutic marker in cancer patients.

Biomimetic Nanosensitizer Potentiates Efficient Glioblastoma Gene-Radiotherapy through Synergistic Hypoxia Mitigation and PLK1 Silencing

Postoperative radiotherapy currently stands as the cornerstone of glioblastoma (GBM) treatment. Nevertheless, low-dose radiotherapy has been proven ineffective for GBM, due to hypoxia in the GBM microenvironment, which renders the resistance to radiation-induced cell death. Moreover, the overexpression of the PLK1 gene in glioma cells enhances GBM proliferation, invasion, metastasis, and resistance to radiation. This study introduced a hybrid membrane-camouflaged biomimetic lipid nanosensitizer (CNL@miPA), which efficiently encapsulated gold nanoclusters (PA) and miR-593-5p by a chimeric membrane derived from lipids, cancer cells, and natural killer cells. CNL@miPA exhibited exceptional blood-brain barrier and tumor tissue penetration, effectively ameliorating hypoxia and synergizing with radiotherapy. By enabling prolonged miRNA circulation in the bloodstream and achieving high enrichment at the tumor site, CNL@miPA significantly suppressed tumor growth in combination treatment, thereby significantly extending the survival period of treated mice. Overall, the developed biomimetic nanosensitizer represented an efficient and multifunctional targeted delivery system, offering a novel strategy for gene-radiotherapy of GBM.

Structural and dynamical insights revealed the anti-glioblastoma potential of withanolides from Withania coagulans against vascular endothelial growth factor receptor (VEGFR)

CONTEXT

Glioblastoma (GBM), well known as grade 4 tumors due to its progressive malignant features such as vascular proliferation and necrosis, is the most aggressive form of primary brain tumor found in adults. Mutations and amplifications in the vascular endothelial growth factor receptor (VEGFR) contribute to almost 25% of GBM tumors. And thus, VEGFR has been declared the primary target in glioblastoma therapeutic strategies. However, many studies have been previously reported that include GBM as global therapeutics challenge, but they lack the molecular level insights that could help in understanding the biological function of a therapeutically important protein playing a major role in the disease and design the best strategies to develop the potential drugs.

METHODS

Therefore, to the best of our knowledge, the present study is the first time of kind, which involves multi-in silico approaches to predict the inhibition potential of withanolides from Withania coagulan against VEGFR. The study is actually based on determining the mode of action of five isolates: withanolide J, withaperuvin, 27-hydroxywithanolide I, coagule E, and coagule E, along with their respective binding energies. Molecular docking simulations revealed primarily four ligands, withanolide J (- 7.33 kJ/mol), 27-withanolide (- 7.01 kJ/mol), ajugine, withaperuvin (- 6.89 kJ/mol), and ajugine E (- 6.39 kJ/mol), to have significant binding potencies against the protein. Ligand binding was found to enhance the confirmational stability of the protein revealed through RMSD analysis, and RMSF assessment revealed the protein residues especially from 900-1000 surrounding the binding of the protein. Structural and dynamics of the protein via dynamics cross-correlation movement (DCCM) and principal component analysis (PCA) in both the unbound form and complexed with most potent ligand, withanolide J, reveal the ligand binding affecting the entire conformational integrity of the protein stabilized by hydrogen bonds and electrostatic attractions. Free energy of binding estimations by means of molecular mechanics Poisson-Boltzmann surface area (MMPBSA) method further revealed the withanolide J to have maximum binding potency of the all ligands. Withanolide J in final was also found to have suitable molecular characterizations to cross the blood-brain barrier (BBB +) and reasonable human intestinal absorption ability determined by ADMET profiling via admetSAR tools.

Laminin Beta 2 Is Localized at the Sites of Blood-Brain Barrier and Its Disruption Is Associated With Increased Vascular Permeability, Histochemical, and Transcriptomic Study

Heterotrimeric extracellular matrix proteins laminins are mostly deposited at basal membranes and are important in repair and neoplasia. Here, we localize laminin beta 2 (LAMB2) at the sites of blood-brain barrier (BBB). Microvasculature (MV) of normal brain is endowed with complete LAMB2 coverage. In contrast, its cognate protein laminin beta 1 (LAMB1) is absent in MV of normal brain but emerges at the sprouting tip of a growing vessels. Similarly, vascular proliferation in high-grade gliomas (HGG) is accompanied by marked overexpression of LAMB1, whereas LAMB2 shows deficient deposition. We find that many brain pathologies with presence of post-gadolinium enhancement (PGE) on magnetic resonance imaging (MRI) show disruption of LAMB2 vascular ensheathment. Inhibition of vascular endothelial growth factor signaling in HGG blocks angiogenesis, suppresses PGE in HGG, prevents expression of LAMB1, and restores LAMB2 vascular coverage. Analysis of single-cell RNA sequencing (scRNA-seq) databases shows that in quiescent brain LAMB2 is predominantly expressed by BBB-associated pericytes (PCs) and endothelial cells (ECs), whereas neither cell types produce LAMB1. In contrast, in HGG, both LAMB1 and 2 are overexpressed by endothelial precursor cells, a phenotypically unique immature group, specific to proliferating hyperplastic MV.

Early Impact of Bevacizumab on the 99m Tc-HYNIC-PSMA-11 Uptake in a Case of Recurrent Glioblastoma Multiforme

ABSTRACT

Glioblastoma multiforme (GBM) is a highly vascularized tumor with reported high prostate-specific membrane antigen (PSMA) expression. On the other hand, bevacizumab as an antiangiogenesis drug is increasingly used in the treatment of GBM recurrence. We present a case of GBM recurrence with significant reduction of 99m Tc-HYNIC-PSMA-11 uptake in her tumor 1 week after administration of 2 doses of bevacizumab with 2 weeks' interval. This case emphasizes the main mechanism of PSMA uptake in GBM secondary to angiogenesis and also implies a potential interaction of bevacizumab with PSMA uptake that should be especially considered during diagnostic and therapeutic application of PSMA radiotracers in GBM.

Spinal and cervical nodal metastases in a patient with glioblastoma

This article presents the rare case of a 54-year-old gentleman with primary glioblastoma developing multiple extracranial metastases 7 months after diagnosis. Initially, the patient complained of progressive headaches, confusion, and weakness of the left arm. Magnetic resonance imaging of the brain showed a right temporoparietal tumor with substantial surrounding subcortical edema and midline shift to the left. Two consecutive craniotomies resulted in complete microsurgical resection of the lesion. Histology was consistent with a World Health Organization grade IV, IDH-wildtype glioblastoma. Further treatment was standard chemoradiation including intensity-modulated radiotherapy with oral temozolomide chemotherapy. Seven months after diagnosis, the cranial lesion progressed, and the patient developed painful metastases in multiple bones and suspicious right-sided cervical lymph nodes. Immunohistochemistry and molecular signature supported the case of a metastatic glioblastoma. Further treatment was palliative radiotherapy of the spinal lesions along with symptomatic pain management. Extracranial metastasis of glioblastoma is a rare complication of which only a few cases have been reported in the literature. Little is known about the precise mechanisms of tumor dissemination and the appropriate treatment.

Brain Stem Glioma Recurrence: Exploring the Therapeutic Frontiers

Gliomas of the brainstem represent a small percentage of central nervous system gliomas in adults. Due to the proximity of the tumor to critical structures, radical surgery is highly challenging and limited to selected cases. In addition, postoperative treatments, which become exclusive to non-operable patients, do not guarantee satisfactory disease control, making the progression of the disease inevitable. Currently, there is a lack of therapeutic options to control tumor growth after the diagnosis of recurrence. The rarity of these tumors, their distinct behavioral characteristics, and the limited availability of tumor tissue necessary for the development of prognostic and predictive biomarkers contribute to the absence of a standardized approach for treating recurrent brainstem gliomas. A salvage radiotherapy (RT) retreatment could represent a promising approach for recurrent brainstem gliomas. However, to date, it has been mainly evaluated in pediatric cases, with few experiences available to assess the most appropriate RT dose, safety, and clinical responses in adult patients. This comprehensive review aims to identify instances of adult patients with recurrent brainstem gliomas subjected to a secondary course of RT, with a specific focus on the analysis of treatment-related toxicity and outcomes. Through this investigation, we endeavor to contribute valuable insights into the viability and efficacy of salvage RT retreatment in managing recurrent brainstem gliomas in the adult population.

Myeloid cells coordinately induce glioma cell-intrinsic and cell-extrinsic pathways for chemoresistance via GP130 signaling

The DNA damage response (DDR) and the blood-tumor barrier (BTB) restrict chemotherapeutic success for primary brain tumors like glioblastomas (GBMs). Coherently, GBMs almost invariably relapse with fatal outcomes. Here, we show that the interaction of GBM and myeloid cells simultaneously induces chemoresistance on the genetic and vascular levels by activating GP130 receptor signaling, which can be addressed therapeutically. We provide data from transcriptomic and immunohistochemical screens with human brain material and pharmacological experiments with a humanized organotypic GBM model, proteomics, transcriptomics, and cell-based assays and report that nanomolar concentrations of the signaling peptide humanin promote temozolomide (TMZ) resistance through DDR activation. GBM mouse models recapitulating intratumoral humanin release show accelerated BTB formation. GP130 blockade attenuates both DDR activity and BTB formation, resulting in improved preclinical chemotherapeutic efficacy. Altogether, we describe an overarching mechanism for TMZ resistance and outline a translatable strategy with predictive markers to improve chemotherapy for GBMs.

Autophagy in glioblastoma: A mechanistic perspective

Glioblastoma (GBM) is one of the most lethal malignancies in humans. Even after surgical resection and aggressive radio- or chemotherapies, patients with GBM can survive for less than 14 months. Extreme inter-tumor and intra-tumor heterogeneity of GBM poses a challenge for resolving recalcitrant GBM pathophysiology. GBM tumor microenvironment (TME) exhibits diverse heterogeneity in cellular composition and processes contributing to tumor progression and therapeutic resistance. Autophagy is such a cellular process; that demonstrates a cell-specific and TME context-dependent role in GBM progression, leading to either the promotion or suppression of GBM progression. Autophagy can regulate GBM cell function directly via regulation of survival, migration, and invasion, or indirectly by affecting GBM TME composition such as immune cell population, tumor metabolism, and glioma stem cells. This review comprehensively investigates the role of autophagy in GBM pathophysiology.

Ultrahigh-Resolution Visualization of Vascular Heterogeneity in Brain Tumors via Magnetic Nanoparticles-Enhanced Susceptibility-Weighted Imaging

The precise assessment of vascular heterogeneity in brain tumors is vital for diagnosing, grading, predicting progression, and guiding treatment decisions. However, currently, there is a significant shortage of high-resolution imaging approaches. Herein, we propose a contrast-enhanced susceptibility-weighted imaging (CE-SWI) utilizing the minimalist dextran-modified Fe3O4 nanoparticles (Dextran@Fe3O4 NPs) for ultrahigh-resolution mapping of vasculature in brain tumors. The Dextran@Fe3O4 NPs are prepared via a facile coprecipitation method under room temperature, and exhibit small hydrodynamic size (28 nm), good solubility, excellent biocompatibility, and high transverse relaxivity (r2*, 159.7 mM-1 s-1) under 9.4 T magnetic field. The Dextran@Fe3O4 NPs-enhanced SWI can increase the contrast-to-noise ratio (CNR) of cerebral vessels to 2.5 times that before injection and achieves ultrahigh-spatial-resolution visualization of microvessels as small as 0.1 mm in diameter. This advanced imaging capability not only allows for the detailed mapping of both enlarged peritumoral drainage vessels and the intratumoral microvessels, but also facilitates the sensitive imaging detection of vascular permeability deterioration in a C6 cells-bearing rat glioblastoma model. Our proposed Dextran@Fe3O4 NPs-enhanced SWI provides a powerful imaging technique with great clinical translation potential for the precise theranostics of brain tumors.

Tumour vasculature at single-cell resolution

Tumours can obtain nutrients and oxygen required to progress and metastasize through the blood supply1. Inducing angiogenesis involves the sprouting of established vessel beds and their maturation into an organized network2,3. Here we generate a comprehensive atlas of tumour vasculature at single-cell resolution, encompassing approximately 200,000 cells from 372 donors representing 31 cancer types. Trajectory inference suggested that tumour angiogenesis was initiated from venous endothelial cells and extended towards arterial endothelial cells. As neovascularization elongates (through angiogenic stages SI, SII and SIII), APLN+ tip cells at the SI stage (APLN+ TipSI) advanced to TipSIII cells with increased Notch signalling. Meanwhile, stalk cells, following tip cells, transitioned from high chemokine expression to elevated TEK (also known as Tie2) expression. Moreover, APLN+ TipSI cells not only were associated with disease progression and poor prognosis but also hold promise for predicting response to anti-VEGF therapy. Lymphatic endothelial cells demonstrated two distinct differentiation lineages: one responsible for lymphangiogenesis and the other involved in antigen presentation. In pericytes, endoplasmic reticulum stress was associated with the proangiogenic BASP1+ matrix-producing pericytes. Furthermore, intercellular communication analysis showed that neovascular endothelial cells could shape an immunosuppressive microenvironment conducive to angiogenesis. This study depicts the complexity of tumour vasculature and has potential clinical significance for anti-angiogenic therapy.

Low-rank prior-based Fast-RPCA for clutter filtering and noise suppression in non-contrast ultrasound microvascular imaging

Accurate and real-time separation of blood signal from clutter and noise signals is a critical step in clinical non-contrast ultrasound microvascular imaging. Despite the widespread adoption of singular value decomposition (SVD) and robust principal component analysis (RPCA) for clutter filtering and noise suppression, the SVD's sensitivity to threshold selection, along with the RPCA's limitations in undersampling conditions and heavy computational burden often result in suboptimal performance in complex clinical applications. To address those challenges, this study presents a novel low-rank prior-based fast RPCA (LP-fRPCA) approach to enhance the adaptability and robustness of clutter filtering and noise suppression with reduced computational cost. A low-rank prior constraint is integrated into the non-convex RPCA model to achieve a robust and efficient approximation of clutter subspace, while an accelerated alternating projection iterative algorithm is developed to improve convergence speed and computational efficiency. The performance of the LP-fRPCA method was evaluated against SVD with a tissue/blood threshold (SVD1), SVD with both tissue/blood and blood/noise thresholds (SVD2), and the classical RPCA based on the alternating direction method of multipliers algorithm through phantom and in vivo non-contrast experiments on rabbit kidneys. In the slow flow phantom experiment of 0.2 mm/s, LP-fRPCA achieved an average increase in contrast ratio (CR) of 10.68 dB, 9.37 dB, and 8.66 dB compared to SVD1, SVD2, and RPCA, respectively. In the in vivo rabbit kidney experiment, the power Doppler results demonstrate that the LP-fRPCA method achieved a superior balance in the trade-off between insufficient clutter filtering and excessive suppression of blood flow. Additionally, LP-fRPCA significantly reduced the runtime of RPCA by up to 94-fold. Consequently, the LP-fRPCA method promises to be a potential tool for clinical non-contrast ultrasound microvascular imaging.

Single-cell atlas of the human brain vasculature across development, adulthood and disease

A broad range of brain pathologies critically relies on the vasculature, and cerebrovascular disease is a leading cause of death worldwide. However, the cellular and molecular architecture of the human brain vasculature remains incompletely understood1. Here we performed single-cell RNA sequencing analysis of 606,380 freshly isolated endothelial cells, perivascular cells and other tissue-derived cells from 117 samples, from 68 human fetuses and adult patients to construct a molecular atlas of the developing fetal, adult control and diseased human brain vasculature. We identify extensive molecular heterogeneity of the vasculature of healthy fetal and adult human brains and across five vascular-dependent central nervous system (CNS) pathologies, including brain tumours and brain vascular malformations. We identify alteration of arteriovenous differentiation and reactivated fetal as well as conserved dysregulated genes and pathways in the diseased vasculature. Pathological endothelial cells display a loss of CNS-specific properties and reveal an upregulation of MHC class II molecules, indicating atypical features of CNS endothelial cells. Cell-cell interaction analyses predict substantial endothelial-to-perivascular cell ligand-receptor cross-talk, including immune-related and angiogenic pathways, thereby revealing a central role for the endothelium within brain neurovascular unit signalling networks. Our single-cell brain atlas provides insights into the molecular architecture and heterogeneity of the developing, adult/control and diseased human brain vasculature and serves as a powerful reference for future studies.

Tumor Dormancy and Reactivation: The Role of Heat Shock Proteins

Tumors are a heterogeneous group of cell masses originating in various organs or tissues. The cellular composition of the tumor cell mass interacts in an intricate manner, influenced by humoral, genetic, molecular, and tumor microenvironment cues that dictate tumor growth or suppression. As a result, tumors undergo a period of a dormant state before their clinically discernible stage, which surpasses the clinical dormancy threshold. Moreover, as a genetically imprinted strategy, early-seeder cells, a distinct population of tumor cells, break off to dock nearby or extravasate into blood vessels to secondary tissues, where they form disseminated solitary dormant tumor cells with reversible capacity. Among the various mechanisms underlying the dormant tumor mass and dormant tumor cell formation, heat shock proteins (HSPs) might play one of the most important roles in how the dormancy program plays out. It is known that numerous aberrant cellular processes, such as malignant transformation, cancer cell stemness, tumor invasion, metastasis, angiogenesis, and signaling pathway maintenance, are influenced by the HSPs. An accumulating body of knowledge suggests that HSPs may be involved in the angiogenic switch, immune editing, and extracellular matrix (ECM) remodeling cascades, crucial genetically imprinted strategies important to the tumor dormancy initiation and dormancy maintenance program. In this review, we highlight the biological events that orchestrate the dormancy state and the body of work that has been conducted on the dynamics of HSPs in a tumor mass, as well as tumor cell dormancy and reactivation. Additionally, we propose a conceptual framework that could possibly underlie dormant tumor reactivation in metastatic relapse.

In situ brain tumor detection using a Raman spectroscopy system-results of a multicenter study

Safe and effective brain tumor surgery aims to remove tumor tissue, not non-tumoral brain. This is a challenge since tumor cells are often not visually distinguishable from peritumoral brain during surgery. To address this, we conducted a multicenter study testing whether the Sentry System could distinguish the three most common types of brain tumors from brain tissue in a label-free manner. The Sentry System is a new real time, in situ brain tumor detection device that merges Raman spectroscopy with machine learning tissue classifiers. Nine hundred and seventy-six in situ spectroscopy measurements and colocalized tissue specimens were acquired from 67 patients undergoing surgery for glioblastoma, brain metastases, or meningioma to assess tumor classification. The device achieved diagnostic accuracies of 91% for glioblastoma, 97% for brain metastases, and 96% for meningiomas. These data show that the Sentry System discriminated tumor containing tissue from non-tumoral brain in real time and prior to resection.

Predicting glioblastoma recurrence using multiparametric MR imaging of non-enhancing peritumoral regions at baseline

Background

To assess the feasibility of multiparametric magnetic resonance imaging in predicting tumor recurrence in nonenhancing peritumoral regions in patients with glioblastoma at baseline.

Methods

Fifty-eight patients with recurrent glioblastoma underwent multiparametric magnetic resonance imaging, including T2-weighted fluid-attenuated inversion recovery, diffusion-weighted imaging, and dynamic susceptibility contrast perfusion-weighted imaging. Nonenhancing peritumoral regions with glioblastoma recurrence were identified by coregistering preoperative and post-recurrent magnetic resonance images. Regions of interest were placed in nonenhancing peritumoral regions with and without tumor recurrence to calculate the apparent diffusion coefficient value, and relative ratios of T2-weighted fluid-attenuated inversion recovery signal intensity, apparent diffusion coefficient, and cerebral blood volume values.

Results

Significant lower relative T2-weighted fluid-attenuated inversion recovery signal intensity, apparent diffusion coefficient, and relative apparent diffusion coefficient but higher relative cerebral blood volume values were found in the nonenhancing peritumoral regions with tumor recurrence than without recurrence (all P < 0.05). The threshold values ≥ 0.89 for relative cerebral blood volume provide the optimal performance for predicting the nonenhancing peritumoral regions with future tumor recurrence, with the sensitivity, specificity, and accuracy of 84.7%, 83.6%, and 85.8%, respectively. The combination of relative T2-weighted fluid-attenuated inversion recovery signal intensity, apparent diffusion coefficient, and relative cerebral blood volume can provide better predictive performance than relative cerebral blood volume (P = 0.015).

Conclusion

The combined use of T2-weighted fluid-attenuated inversion recovery, diffusion-weighted imaging, and dynamic susceptibility contrast perfusion-weighted imaging can effectively estimate the risk of future tumor recurrence at baseline.

Mesenchymal glioma stem cells trigger vasectasia-distinct neovascularization process stimulated by extracellular vesicles carrying EGFR

Targeting neovascularization in glioblastoma (GBM) is hampered by poor understanding of the underlying mechanisms and unclear linkages to tumour molecular landscapes. Here we report that different molecular subtypes of human glioma stem cells (GSC) trigger distinct endothelial responses involving either angiogenic or circumferential vascular growth (vasectasia). The latter process is selectively triggered by mesenchymal (but not proneural) GSCs and is mediated by a subset of extracellular vesicles (EVs) able to transfer EGFR/EGFRvIII transcript to endothelial cells. Inhibition of the expression and phosphorylation of EGFR in endothelial cells, either pharmacologically (Dacomitinib) or genetically (gene editing), abolishes their EV responses in vitro and disrupts vasectasia in vivo. Therapeutic inhibition of EGFR markedly extends anticancer effects of VEGF blockade in mice, coupled with abrogation of vasectasia and prolonged survival. Thus, vasectasia driven by intercellular transfer of oncogenic EGFR may represent a new therapeutic target in a subset of GBMs.

Whole brain morphologic features improve the predictive accuracy of IDH status and VEGF expression levels in gliomas

Glioma is a systemic disease that can induce micro and macro alternations of whole brain. Isocitrate dehydrogenase and vascular endothelial growth factor are proven prognostic markers and antiangiogenic therapy targets in glioma. The aim of this study was to determine the ability of whole brain morphologic features and radiomics to predict isocitrate dehydrogenase status and vascular endothelial growth factor expression levels. This study recruited 80 glioma patients with isocitrate dehydrogenase wildtype and high vascular endothelial growth factor expression levels, and 102 patients with isocitrate dehydrogenase mutation and low vascular endothelial growth factor expression levels. Virtual brain grafting, combined with Freesurfer, was used to compute morphologic features including cortical thickness, LGI, and subcortical volume in glioma patient. Radiomics features were extracted from multiregional tumor. Pycaret was used to construct the machine learning pipeline. Among the radiomics models, the whole tumor model achieved the best performance (accuracy 0.80, Area Under the Curve 0.86), while, after incorporating whole brain morphologic features, the model had a superior predictive performance (accuracy 0.82, Area Under the Curve 0.88). The features contributed most in predicting model including the right caudate volume, left middle temporal cortical thickness, first-order statistics, shape, and gray-level cooccurrence matrix. Pycaret, based on morphologic features, combined with radiomics, yielded highest accuracy in predicting isocitrate dehydrogenase mutation and vascular endothelial growth factor levels, indicating that morphologic abnormalities induced by glioma were associated with tumor biology.

Spatial analysis of tissue immunity and vascularity by light sheet fluorescence microscopy

The pathogenesis of cancer and cardiovascular diseases is subjected to spatiotemporal regulation by the tissue microenvironment. Multiplex visualization of the microenvironmental components, including immune cells, vasculature and tissue hypoxia, provides critical information underlying the disease progression and therapy resistance, which is often limited by imaging depth and resolution in large-volume tissues. To this end, light sheet fluorescence microscopy, following tissue clarification and immunostaining, may generate three-dimensional high-resolution images at a whole-organ level. Here we provide a detailed description of light sheet fluorescence microscopy imaging analysis of immune cell composition, vascularization, tissue perfusion and hypoxia in mouse normal brains and hearts, as well as brain tumors. We describe a procedure for visualizing tissue vascularization, perfusion and hypoxia with a transgenic vascular labeling system. We provide the procedures for tissue collection, tissue semi-clearing and immunostaining. We further describe standard methods for analyzing tissue immunity and vascularity. We anticipate that this method will facilitate the spatial illustration of structure and function of the tissue microenvironmental components in cancer and cardiovascular diseases. The procedure requires 1-2 weeks and can be performed by users with expertise in general molecular biology.

Antibiotics treatment promotes vasculogenesis in the brain of glioma-bearing mice

In recent years, several studies described the close relationship between the composition of gut microbiota and brain functions, highlighting the importance of gut-derived metabolites in mediating neuronal and glial cells cross-talk in physiological and pathological condition. Gut dysbiosis may affects cerebral tumors growth and progression, but the specific metabolites involved in this modulation have not been identified yet. Using a syngeneic mouse model of glioma, we have investigated the role of dysbiosis induced by the administration of non-absorbable antibiotics on mouse metabolome and on tumor microenvironment. We report that antibiotics treatment induced: (1) alteration of the gut and brain metabolome profiles; (2) modeling of tumor microenvironment toward a pro-angiogenic phenotype in which microglia and glioma cells are actively involved; (3) increased glioma stemness; (4) trans-differentiation of glioma cells into endothelial precursor cells, thus increasing vasculogenesis. We propose glycine as a metabolite that, in ABX-induced dysbiosis, shapes brain microenvironment and contributes to glioma growth and progression.

Insights into the glioblastoma tumor microenvironment: current and emerging therapeutic approaches

Glioblastoma (GB) is an intrusive and recurrent primary brain tumor with low survivability. The heterogeneity of the tumor microenvironment plays a crucial role in the stemness and proliferation of GB. The tumor microenvironment induces tumor heterogeneity of cancer cells by facilitating clonal evolution and promoting multidrug resistance, leading to cancer cell progression and metastasis. It also plays an important role in angiogenesis to nourish the hypoxic tumor environment. There is a strong interaction of neoplastic cells with their surrounding microenvironment that comprise several immune and non-immune cellular components. The tumor microenvironment is a complex network of immune components like microglia, macrophages, T cells, B cells, natural killer (NK) cells, dendritic cells and myeloid-derived suppressor cells, and non-immune components such as extracellular matrix, endothelial cells, astrocytes and neurons. The prognosis of GB is thus challenging, making it a difficult target for therapeutic interventions. The current therapeutic approaches target these regulators of tumor micro-environment through both generalized and personalized approaches. The review provides a summary of important milestones in GB research, factors regulating tumor microenvironment and promoting angiogenesis and potential therapeutic agents widely used for the treatment of GB patients.

The VEGFs/VEGFRs system in Alzheimer's and Parkinson's diseases: Pathophysiological roles and therapeutic implications

The vascular endothelial growth factors (VEGFs) and their cognate receptors (VEGFRs), besides their well-known involvement in physiological angiogenesis/lymphangiogenesis and in diseases associated to pathological vessel formation, play multifaceted functions in the central nervous system (CNS). In addition to shaping brain development, by controlling cerebral vasculogenesis and regulating neurogenesis as well as astrocyte differentiation, the VEGFs/VEGFRs axis exerts essential functions in the adult brain both in physiological and pathological contexts. In this article, after describing the physiological VEGFs/VEGFRs functions in the CNS, we focus on the VEGFs/VEGFRs involvement in neurodegenerative diseases by reviewing the current literature on the rather complex VEGFs/VEGFRs contribution to the pathogenic mechanisms of Alzheimer's (AD) and Parkinson's (PD) diseases. Thereafter, based on the outcome of VEGFs/VEGFRs targeting in animal models of AD and PD, we discuss the factual relevance of pharmacological VEGFs/VEGFRs modulation as a novel and potential disease-modifying approach for these neurodegenerative pathologies. Specific VEGFRs targeting, aimed at selective VEGFR-1 inhibition, while preserving VEGFR-2 signal transduction, appears as a promising strategy to hit the molecular mechanisms underlying AD pathology. Moreover, therapeutic VEGFs-based approaches can be proposed for PD treatment, with the aim of fine-tuning their brain levels to amplify neurotrophic/neuroprotective effects while limiting an excessive impact on vascular permeability.

Radiomics Multifactorial in Silico Model for Spatial Prediction of Glioblastoma Progression and Recurrence: A Proof-of-Concept

BACKGROUND

Radiomics-based prediction of glioblastoma spatial progression and recurrence may improve personalized strategies. However, most prototypes are based on limited monofactorial Gompertzian models of tumor growth. The present study consists of a proof of concept on the accuracy of a radiomics multifactorial in silico model in predicting short-term spatial growth and recurrence of glioblastoma.

METHODS

A radiomics-based biomathematical multifactorial in silico model was developed using magnetic resonance imaging (MRI) data from a 53-year-old patient with newly diagnosed glioblastoma of the right supramarginal gyrus. Raw and optimized models were derived from the MRI at diagnosis and matched to the preoperative MRI obtained 28 days after diagnosis to test the accuracy in predicting the short-term spatial growth of the tumor. An additional optimized model was derived from the early postoperative MRI and matched to the MRI documenting tumor recurrence to test spatial accuracy in predicting the location of recurrence. The spatial prediction accuracy of the model was reported as an average Jaccard index.

RESULTS

Optimized models yielded an average Jaccard index of 0.69 and 0.26 for short-term tumor growth and long-term recurrence site, respectively.

CONCLUSIONS

The present radiomics-based multifactorial in silico model was feasible, reliable, and accurate for short-term spatial prediction of glioblastoma progression. The predictive value for the spatial location of recurrence was still low, and refinements in the description of tissue reorganization in the peritumoral and resected areas may be critical to optimize accuracy further.

Engineered smart materials for RNA based molecular therapy to treat Glioblastoma

Glioblastoma (GBM) is an aggressive malignancy of the central nervous system (CNS) that remains incurable despite the multitude of improvements in cancer therapeutics. The conventional chemo and radiotherapy post-surgery have only been able to improve the prognosis slightly; however, the development of resistance and/or tumor recurrence is almost inevitable. There is a pressing need for adjuvant molecular therapies that can successfully and efficiently block tumor progression. During the last few decades, non-coding RNAs (ncRNAs) have emerged as key players in regulating various hallmarks of cancer including that of GBM. The levels of many ncRNAs are dysregulated in cancer, and ectopic modulation of their levels by delivering antagonists or overexpression constructs could serve as an attractive option for cancer therapy. The therapeutic potential of several types of ncRNAs, including miRNAs, lncRNAs, and circRNAs, has been validated in both in vitro and in vivo models of GBM. However, the delivery of these RNA-based therapeutics is highly challenging, especially to the tumors of the brain as the blood-brain barrier (BBB) poses as a major obstacle, among others. Also, since RNA is extremely fragile in nature, careful considerations must be met while designing a delivery agent. In this review we have shed light on how ncRNA therapy can overcome the limitations of its predecessor conventional therapy with an emphasis on smart nanomaterials that can aide in the safe and targeted delivery of nucleic acids to treat GBM. Additionally, critical gaps that currently exist for successful transition from viral to non-viral vector delivery systems have been identified. Finally, we have provided a perspective on the future directions, potential pathways, and target areas for achieving rapid clinical translation of, RNA-based macromolecular therapy to advance the effective treatment of GBM and other related diseases.

The therapeutic effect of MSCs and their extracellular vesicles on neuroblastoma

Neuroblastoma is a common inflammatory-related cancer during infancy. Standard treatment modalities including surgical interventions, high-dose chemotherapy, radiotherapy, and immunotherapy are not able to increase survival rate and reduce tumor relapse in high-risk patients. Mesenchymal stem cells (MSCs) are known for their tumor-targeting and immunomodulating properties. MSCs could be engineered to express anticancer agents (i.e., growth factors, cytokines, pro-apoptotic agents) or deliver oncolytic viruses in the tumor microenvironment. As many functions of MSCs are mediated through their secretome, researchers have tried to use extracellular vesicles (EVs) from MSCs for targeted therapy of neuroblastoma. Here, we reviewed the studies to figure out whether the use of MSCs could be worthwhile in neuroblastoma therapy or not. Native MSCs have shown a promoting or inhibiting role in cancers including neuroblastoma. Therefore, MSCs are proposed as a vehicle to deliver anticancer agents such as oncolytic viruses to the neuroblastoma tumor microenvironment. Although modified MSCs or their EVs have been shown to suppress the tumorigenesis of neuroblastoma, further pre-clinical and clinical studies are required to come to a conclusion.

Exploring the association of glioma tumor residuals from incongruent [18F]FET PET/MR imaging with tumor proliferation using a multiparametric MRI radiomics nomogram

PURPOSE

The study aimed to using multiparametric MRI radiomics to predict glioma tumor residuals (TRFET over MR) derived from incongruent [18F]fluoroethyl-L-tyrosine ([18F]FET) PET/MR imaging.

METHODS

One hundred ten patients with gliomas who underwent [18F]FET PET/MR scanning were retrospectively analyzed. The TRFET over MR was identified by the discrepancy-PET that the extent of resection (EOR) based on MRI subtracted the biological tumor volume on PET images. The MRI parameters and radiomics features were extracted based on EOR and selected by the least absolute shrinkage and selection operator to construct radiomics score (Rad-score). The correlation network analysis of all features was analyzed by Spearman's correlation tests. The methods for evaluating the clinical usefulness consisted of the receiver operating characteristic curve, the calibration curve, and decision curve analysis.

RESULTS

The Rad-score of the patients with the TRFET over MR was significantly higher than those with the non TRFET over MR (p < 0.001). The Rad-score was significantly correlated with the discrepancy-PET (r = 0.72, p < 0.001), Ki-67 level (r = 0.76, p < 0.001), and epidermal growth factor receptor (EGFR) of gliomas (r = 0.75, p < 0.001), respectively. Moreover, there was a difference of the correlation network analysis between the TRPET over MR group and non TRFET over MR group. The nomogram combing Rad-score and clinical features had the greatest performance in predicting TRFET over MR (AUC = 0.90/0.87, training/testing). There was a significant difference in prognosis (median OS, 17 m vs. 43 m) between patients with TRFET over MR and non TRFET over MR based on nomogram prediction (p < 0.001).

CONCLUSION

The nomogram based on MRI radiomics would predict gliomas tumor residuals caused by the absence of 18F-PET PET examination and adjust EOR to improve prognosis.

Potent in vivo efficacy of oral gallium maltolate in treatment-resistant glioblastoma

Background

Treatment-resistant glioblastoma (trGBM) is an aggressive brain tumor with a dismal prognosis, underscoring the need for better treatment options. Emerging data indicate that trGBM iron metabolism is an attractive therapeutic target. The novel iron mimetic, gallium maltolate (GaM), inhibits mitochondrial function via iron-dependent and -independent pathways.

Methods

In vitro irradiated adult GBM U-87 MG cells were tested for cell viability and allowed to reach confluence prior to stereotactic implantation into the right striatum of male and female athymic rats. Advanced MRI at 9.4T was carried out weekly starting two weeks after implantation. Daily oral GaM (50mg/kg) or vehicle were provided on tumor confirmation. Longitudinal MRI parameters were processed for enhancing tumor ROIs in OsiriX 8.5.1 (lite) with Imaging Biometrics Software (Imaging Biometrics LLC). Statistical analyses included Cox proportional hazards regression models, Kaplan-Meier survival plots, linear mixed model comparisons, and t-statistic for slopes comparison as indicator of tumor growth rate.

Results

In this study we demonstrate non-invasively, using longitudinal MRI surveillance, the potent antineoplastic effects of GaM in a novel rat xenograft model of trGBM, as evidenced by extended suppression of tumor growth (23.56 mm3/week untreated, 5.76 mm3/week treated, P < 0.001), a blunting of tumor perfusion, and a significant survival benefit (median overall survival: 30 days untreated, 56 days treated; P < 0.001). The therapeutic effect was confirmed histologically by the presence of abundant cytotoxic cellular swelling, a significant reduction in proliferation markers (P < 0.01), and vessel normalization characterized by prominent vessel pruning, loss of branching, and uniformity of vessel lumina. Xenograft tumors in the treatment group were further characterized by an absence of an invasive edge and a significant reduction in both, MIB-1% and mitotic index (P < 0.01 each). Transferrin receptor and ferroportin expression in GaM-treated tumors illustrated cellular iron deprivation. Additionally, treatment with GaM decreased the expression of pro-angiogenic markers (von Willebrand Factor and VEGF) and increased the expression of anti-angiogenic markers, such as Angiopoietin-2.

Conclusion

Monotherapy with the iron-mimetic GaM profoundly inhibits trGBM growth and significantly extends disease-specific survival in vivo.

Targeted Glioma Therapy-Clinical Trials and Future Directions

Glioblastoma multiforme (GBM) is the most common type of glioma, with a median survival of 14.6 months post-diagnosis. Understanding the molecular profile of such tumors allowed the development of specific targeted therapies toward GBM, with a major role attributed to tyrosine kinase receptor inhibitors and immune checkpoint inhibitors. Targeted therapeutics are drugs that work by specific binding to GBM-specific or overexpressed markers on the tumor cellular surface and therefore contain a recognition moiety linked to a cytotoxic agent, which produces an antiproliferative effect. In this review, we have summarized the available information on the targeted therapeutics used in clinical trials of GBM and summarized current obstacles and advances in targeted therapy concerning specific targets present in GBM tumor cells, outlined efficacy endpoints for major classes of investigational drugs, and discussed promising strategies towards an increase in drug efficacy in GBM.

Treatment evaluation by volumetric segmentation in pediatric optic pathway glioma: evaluation of the effect of bevacizumab on intra-tumor components

PURPOSE

Progressive pediatric optic pathway gliomas (OPGs) are treated by diverse systemic antitumor modalities. Refined insights on the course of intra-tumoral components are limited.

METHODS

We performed an exploratory study on the longitudinal volumetric course of different (intra-)tumor components by manual segmentation of MRI at the start and after 3, 6 and 12 months of bevacizumab (BVZ) treatment.

RESULTS

Thirty-one patients were treated with BVZ (median 12 months, range: 2-39 months). During treatment the total tumor volume decreased with median 19.9% (range: - 62.3 to + 29.7%; n = 30) within the first 3 months, decreased 19.0% (range: - 68.8 to + 96.1%; n = 28) between start and 6 months and 27.2% (range: -73.4 to + 36.0%; n = 21) between start and 12 months. Intra-tumoral cysts were present in 12 OPGs, all showed a decrease of volume during treatment. The relative contrast enhanced volume of NF1 associated OPG (n = 11) showed an significant reduction compared to OPG with a KIAA1549-BRAF fusion (p < 0.01). Three OPGs progressed during treatment, but were not preceded by an increase of relative contrast enhancement.

CONCLUSION

Treatment with BVZ of progressive pediatric OPGs leads to a decrease of both total tumor volume and cystic volume for the majority of OPGs with emphasis on the first three months. NF1 and KIAA1549-BRAF fusion related OPGs showed a different (early) treatment effect regarding the tumor enhancing component on MRI, which did not correlate with tumor volume changes. Future research is necessary to further evaluate these findings and its relevance to clinical outcome parameters.

Computational Fractal-Based Analysis of Brain Tumor Microvascular Networks

Brain parenchyma microvasculature is set in disarray in the presence of tumors, and malignant brain tumors are among the most vascularized neoplasms in humans. As microvessels can be easily identified in histologic specimens, quantification of microvascularity can be used alone or in combination with other histological features to increase the understanding of the dynamic behavior, diagnosis, and prognosis of brain tumors. Different brain tumors, and even subtypes of the same tumor, show specific microvascular patterns, as a kind of "microvascular fingerprint," which is particular to each histotype. Reliable morphometric parameters are required for the qualitative and quantitative characterization of the neoplastic angioarchitecture, although the lack of standardization of a technique able to quantify the microvascular patterns in an objective way has limited the "morphometric approach" in neuro-oncology.In this chapter, we focus on the importance of computational-based morphometrics, for the objective description of tumoral microvascular fingerprinting. By also introducing the concept of "angio-space," which is the tumoral space occupied by the microvessels, we here present fractal analysis as the most reliable computational tool able to offer objective parameters for the description of the microvascular networks.The spectrum of different angioarchitectural configurations can be quantified by means of Euclidean and fractal-based parameters in a multiparametric analysis, aimed to offer surrogate biomarkers of cancer. Such parameters are here described from the methodological point of view (i.e., feature extraction) as well as from the clinical perspective (i.e., relation to underlying physiology), in order to offer new computational parameters to the clinicians with the final goal of improving diagnostic and prognostic power of patients affected by brain tumors.