Expression and prognostic impact of matrix metalloproteinase-2 (MMP-2) in astrocytomas

A case of epithelioid glioblastoma with lung metastases in a young Cane Corso dog

Astrocytomas are relatively common primary brain tumours of humans and companion animals. In dogs, they represent approximately 17-28% of primary central nervous system tumours. However, extracranial metastasis is extremely rare. This case report describes a grade IV astrocytoma (glioblastoma) in the cerebrum of a young Cane Corso dog with pulmonary metastases. The diagnosis was obtained via histopathological morphology and immunophenotyping, which showed strong positivity for glial fibrillary acidic protein, vimentin and connexin-43. The glioblastoma in this Cane Corso had epithelioid morphology with histological features of malignancy including high mitotic count, microvascular proliferation, serpentine necrosis and subventricular zone involvement. Epithelioid glioblastoma is a rare subtype that has only relatively recently been formally acknowledged in human medicine and it can also pose a diagnostic challenge in veterinary medicine.

Multilayer nanodrug delivery system with spatiotemporal drug release improves tumor microenvironment for synergistic anticancer therapy

The inflammatory response is one of the general symptoms that accompany tumorigenesis, the pro-inflammatory factors cyclooxygenase-2 (COX-2) and COX-2-derived prostaglandin-2 (PGE-2) in the inflammatory environment surrounding tumors possess promoting tumor development, metastasis and angiogenesis effects. In addition, the hypoxic environment of tumors severely limits the effectiveness of photodynamic therapy (PDT). In this study, a universal extracellular-intracellular 'on-demand' release nanomedicine DOX@PDA-ICG@MnO2@GN-CEL was developed for the combined fight against malignant tumors using a spatiotemporal controlled gelatin coated polydopamine (PDA@GN) as the carrier and loaded with the chemotherapeutic drug doxorubicin (DOX), the photosensitizer indocyanine green (ICG), the PDT enhancer MnO2and the anti-inflammatory drug celecoxib (CEL) individually. Our results showed that DOX@PDA-ICG@MnO2@GN-CEL could release CEL extracellularly by matrix metalloproteinase-2 response and inhibit the COX-2/PGE-2 pathway, reduce chemotherapy resistance and attenuate the concurrent inflammation. After entering the tumor cells, the remaining DOX@PDA-ICG@MnO2released DOX, ICG and MnO2intracellularly through PDA acid response. MnO2promoted the degradation of endogenous H2O2to generate oxygen under acidic conditions to alleviate the tumor hypoxic environment, enhance PDT triggered by ICG. PDA and ICG exhibited photothermal therapy synergistically, and DOX exerted chemotherapy with reduced chemotherapy resistance. The dual responsive drug release switch enabled the chemotherapeutic, photothermal, photodynamic and anti-inflammatory drugs precisely acted on different sites of tumor tissues and realized a promising multimodal combination therapy.

Proline Metabolism in WHO G4 Gliomas Is Altered as Compared to Unaffected Brain Tissue

Proline metabolism has been identified as a significant player in several neoplasms, but knowledge of its role in gliomas is limited despite it providing a promising line of pursuit. Data on proline metabolism in the brain are somewhat historical. This study aims to investigate alterations of proline metabolism in gliomas of WHO grade 4 (GG4) in the context of the brain. A total of 20 pairs of samples were studied, consisting of excised tumor and unaffected brain tissue, obtained when partial brain resection was required to reach deep-seated lesions. Levels of proline oxidase/proline dehydrogenase (POX/PRODH), Δ1-pyrroline-5-carboxylate reductases (PYCR1/2/3), prolidase (PEPD), and metalloproteinases (MMP-2, MMP-9) were assessed, along with the concentration of proline and proline-related metabolites. In comparison to normal brain tissue, POX/PRODH expression in GG4 was found to be suppressed, while PYCR1 expression and activity of PEPD, MMP-2, and -9 were upregulated. The GG4 proline concentration was 358% higher. Hence, rewiring of the proline metabolism in GG4 was confirmed for the first time, with a low-POX/PRODH/high-PYCR profile. High PEPD and MMPs activity is in keeping with GG4-increased collagen turnover and local aggressiveness. Further studies on the mechanisms of the interplay between altered proline metabolism and the GG4 microenvironment are warranted.

Matrix metalloproteinases are associated with brain atrophy in cognitively unimpaired individuals

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been linked to age-related neurodegeneration and Alzheimer's disease (AD), but their role in normal aging is poorly understood. We used linear mixed models to determine if baseline or rate of yearly change in cerebrospinal fluid (CSF) levels of MMP-2; MMP-3; MMP-10; TIMP-123 (composite of TIMP-1, TIMP-2, and TIMP-3); or TIMP-4 predicted changes in bilateral entorhinal cortex thickness, hippocampal volume, or lateral ventricle volume in cognitively unimpaired individuals. We also assessed effects on the CSF AD biomarkers amyloid-β42 and phosphorylated tau181. Low baseline levels of MMP-3 predicted larger ventricle volumes and more entorhinal cortex thinning. Increased CSF MMP-2 levels over time predicted more entorhinal thinning, hippocampal atrophy, and ventricular expansion, while increased TIMP-123 over time predicted ventricular expansion. No MMP/TIMPs predicted changes in CSF AD biomarkers. Notably, we show for the first time that longitudinal increases in MMP-2 and TIMP-123 levels may predict age-associated brain atrophy. In conclusion, MMPs and TIMPs may play a role in brain atrophy in cognitively unimpaired aging.

Investigating the effect of vandetanib and celecoxib combination on angiogenesis

Objective

Angiogenesis plays an important role in various physiological and pathological conditions and is essential for tumor growth and metastasis. The aim of this study was to evaluate the effect of a combination of vandetanib and celecoxib on angiogenic tube formation and its effect on angiogenic genes (MMP-2 and MMP-9) using an in vitro model of human umbilical vein endothelial cells (HUVECs).

Methods

HUVECs were cultured and verified by flow cytometry. HUVECs were then treated with vandetanib, celecoxib, and the combination of both drugs. Then, we investigated cell viability and cell apoptosis by MTT assays and flow cytometry. The process of angiogenesis was analyzed by tube formation assays, and the effect on angiogenic genes was determined by RT-qPCR.

Results

HUVECs were positive for CD144 and negative for CD14. Vandetanib, celecoxib, and their combination inhibited HUVEC viability in a dose-dependent manner (p < 0.001). The rate of apoptosis was 13.1%, 9%, and 23.7% (p < 0.001) when treated with vandetanib, celecoxib, or the combination of both drugs, respectively. Vandetanib inhibited tube formation by 43.7%, celecoxib by 21%, and their combination by 77.3% (p < 0.001), respectively. RT-qPCR revealed that both vandetanib and celecoxib reduced the expression levels of MMP-2 and MMP-9, and their combination resulted in an even greater extent of reduction in expression levels (p < 0.001).

Conclusion

Celecoxib enhanced the effect of vandetanib in inhibiting in vitro angiogenesis and the combination of these two drugs led to even greater extents of inhibition than vandetanib alone.

Invadopodia associated Thrombospondin-1 contributes to a post-therapy pro-invasive response in glioblastoma cells

A critical challenge in the treatment of glioblastoma (GBM) is its highly invasive nature which promotes cell migration throughout the brain and hinders surgical resection and effective drug delivery. GBM cells demonstrate augmented invasive capabilities following exposure to the current gold standard treatment of radiotherapy (RT) and concomitant and adjuvant temozolomide (TMZ), resulting in rapid disease recurrence. Elucidating the mechanisms employed by post-treatment invasive GBM cells is critical to the development of more effective therapies. In this study, we utilized a Nanostring® Cancer Progression gene expression panel to identify candidate genes that may be involved in enhanced GBM cell invasion after treatment with clinically relevant doses of RT/TMZ. Our findings identified thrombospondin-1 (THBS1) as a pro-invasive gene that is upregulated in these cells. Immunofluorescence staining revealed that THBS1 localised within functional matrix-degrading invadopodia that formed on the surface of GBM cells. Furthermore, overexpression of THBS1 resulted in enhanced GBM cell migration and secretion of MMP-2, which was reduced with silencing of THBS1. The preliminary data demonstrates that THBS1 is associated with invadopodia in GBM cells and is likely involved in the invadopodia-mediated invasive process in GBM cells exposed to RT/TMZ treatment. Therapeutic inhibition of THBS1-mediated invadopodia activity, which facilitates GBM cell invasion, should be further investigated as a treatment for GBM.

Clinical Theranostics Trademark of Exosome in Glioblastoma Metastasis

Glioblastoma (GBM) is an aggressive type of cancer that has led to the death of a large population. The traditional approach fails to develop a solution for GBM's suffering life. Extensive research into tumor microenvironments (TME) indicates that TME extracellular vesicles (EVs) play a vital role in cancer development and progression. EVs are classified into microvacuoles, apoptotic bodies, and exosomes. Exosomes are the most highlighted domains in cancer research. GBM cell-derived exosomes participate in multiple cancer progression events such as immune suppression, angiogenesis, premetastatic niche formation (PMN), ECM (extracellular matrix), EMT (epithelial-to-mesenchymal transition), metastasis, cancer stem cell development and therapeutic and drug resistance. GBM exosomes also carry the signature of a glioblastoma-related status. The exosome-based GBM examination is part of the new generation of liquid biopsy. It also solved early diagnostic limitations in GBM. Traditional therapeutic approaches do not cross the blood-brain barrier (BBB). Exosomes are a game changer in GBM treatment and it is emerging as a potential platform for effective, efficient, and specific therapeutic development. In this review, we have explored the exosome-GBM interlink, the clinical impact of exosomes on GBM biomarkers, the therapeutics signature of exosomes in GBM, exosome-based research challenges, and future directions in GBM. Therefore, the GBM-derived exosomes offer unique therapeutic opportunities, which are currently under preclinical and clinical testing.

Progesterone and its metabolite allopregnanolone promote invasion of human glioblastoma cells through metalloproteinase‑9 and cSrc kinase

Glioblastomas are the most aggressive and common primary brain tumors in adults. Glioblastoma cells have a great capacity to migrate and invade the brain parenchyma, often reaching the contralateral hemisphere. Progesterone (P4) and its metabolite, allopregnanolone (3α-THP), promote the migration and invasion of human glioblastoma-derived cells. P4 induces migration in glioblastoma cells by the activation of the proto-oncogene tyrosine-protein kinase Src (cSrc) and focal adhesion kinase (Fak). In breast cancer cells, cSrc and Fak promote invasion by increasing the expression and activation of extracellular matrix metalloproteinases (MMPs). However, the mechanism of action by which P4 and 3a-THP promote invasion in glioblastoma cells remains unclear. The effects of P4 and 3α-THP on the protein expression levels of MMP-2 and -9 and the participation of cSrc in progestin effects in U251 and U87 human glioblastoma-derived cells were evaluated. It was determined by western blotting that the P4 increased the protein expression level of MMP-9 in U251 and U87 cells, and 3α-THP increased the protein expression level of MMP-9 in U87 cells. None of these progestins modified MMP-2 protein expression levels. The increase in MMP-9 expression was reduced when the intracellular progesterone receptor and cSrc expression were blocked with small interfering RNAs. Cell invasion induced by P4 and 3α-THP was also blocked by inhibiting cSrc activity with PP2 or by cSrc gene silencing. These results suggest that P4 and its metabolite 3α-THP induce the invasion of glioblastoma cells by increasing MMP-9 expression through the cSrc kinase family. The results of this study provide information of interest in the context of targeted therapies against molecular pathways involved in glioblastoma invasion.

High VEGFA Expression Is Associated with Improved Progression-Free Survival after Bevacizumab Treatment in Recurrent Glioblastoma

Glioblastoma (GB) is one of the deadliest human cancers. Many GB patients do not respond to treatment, and inevitably die within a median of 15-18 months post-diagnosis, highlighting the need for reliable biomarkers to aid clinical management and treatment evaluation. The GB microenvironment holds tremendous potential as a source of biomarkers; several proteins such as MMP-2, MMP-9, YKL40, and VEGFA have been identified as being differentially expressed in GB patient samples. Still to date, none of these proteins have been translated into relevant clinical biomarkers. This study evaluated the expression of MMP-2, MMP-9, YKL40, and VEGFA in a series of GBs and their impact on patient outcome. High levels of VEGFA expression were significantly associated with improved progression-free survival after bevacizumab treatment, thus having potential as a tissue biomarker for predicting patients' response to bevacizumab. Noteworthily, VEGFA expression was not associated with patient outcome after temozolomide treatment. To a lesser extent, YKL40 also provided significant information regarding the extent of bevacizumab treatment. This study highlights the importance of studying secretome-associated proteins as GB biomarkers and identifies VEGFA as a promising marker for predicting response to bevacizumab.

Anticancer Mechanism of Flavonoids on High-Grade Adult-Type Diffuse Gliomas

High-grade adult-type diffuse gliomas are the most common and deadliest malignant adult tumors of the central nervous system. Despite the advancements in the multimodality treatment of high-grade adult-type diffuse gliomas, the five-year survival rates still remain poor. The biggest challenge in treating high-grade adult-type diffuse gliomas is the intra-tumor heterogeneity feature of the glioma tumors. Introducing dietary flavonoids to the current high-grade adult-type diffuse glioma treatment strategies is crucial to overcome this challenge, as flavonoids can target several molecular targets. This review discusses the anticancer mechanism of flavonoids (quercetin, rutin, chrysin, apigenin, naringenin, silibinin, EGCG, genistein, biochanin A and C3G) through targeting molecules associated with high-grade adult-type diffuse glioma cell proliferation, apoptosis, oxidative stress, cell cycle arrest, migration, invasion, autophagy and DNA repair. In addition, the common molecules targeted by the flavonoids such as Bax, Bcl-2, MMP-2, MMP-9, caspase-8, caspase-3, p53, p38, Erk, JNK, p38, beclin-1 and LC3B were also discussed. Moreover, the clinical relevance of flavonoid molecular targets in high-grade adult-type diffuse gliomas is discussed with comparison to small molecules inhibitors: ralimetinib, AMG232, marimastat, hydroxychloroquine and chloroquine. Despite the positive pre-clinical results, further investigations in clinical studies are warranted to substantiate the efficacy and safety of the use of flavonoids on high-grade adult-type diffuse glioma patients.

The Regulation of Microglial Cell Polarization in the Tumor Microenvironment: A New Potential Strategy for Auxiliary Treatment of Glioma-A Review

Glioma is the most common primary tumor of the central nervous system and normally should be treated by synthetic therapy, mainly with surgical operation assisted by radiotherapy and chemotherapy; however, the therapeutic effect has not been satisfactory, and the 5-year survival rates of anaplastic glioma and glioblastoma are 29.7% and 5.5%, respectively. To identify a more efficient strategy to treat glioma, in recent years, the influence of the inflammatory microenvironment on the progression of glioma has been studied. Various immunophenotypes exist in microglial cells, each of which has a different functional property. In this review, references about the phenotypic conversion of microglial cell polarity in the microenvironment were briefly summarized, and the differences in polarized state and function, their influences on glioma progression under different physiological and pathological conditions, and the interactive effects between the two were mainly discussed. Certain signaling molecules and regulatory pathways involved in the microglial cell polarization process were investigated, and the feasibility of targeted regulation of microglial cell conversion to an antitumor phenotype was analyzed to provide new clues for the efficient auxiliary treatment of neural glioma.

Anoctamins and Calcium Signalling: An Obstacle to EGFR Targeted Therapy in Glioblastoma?

Glioblastoma is the most common form of high-grade glioma in adults and has a poor survival rate with very limited treatment options. There have been no significant advancements in glioblastoma treatment in over 30 years. Epidermal growth factor receptor is upregulated in most glioblastoma tumours and, therefore, has been a drug target in recent targeted therapy clinical trials. However, while many inhibitors and antibodies for epidermal growth factor receptor have demonstrated promising anti-tumour effects in preclinical models, they have failed to improve outcomes for glioblastoma patients in clinical trials. This is likely due to the highly plastic nature of glioblastoma tumours, which results in therapeutic resistance. Ion channels are instrumental in the development of many cancers and may regulate cellular plasticity in glioblastoma. This review will explore the potential involvement of a class of calcium-activated chloride channels called anoctamins in brain cancer. We will also discuss the integrated role of calcium channels and anoctamins in regulating calcium-mediated signalling pathways, such as epidermal growth factor signalling, to promote brain cancer cell growth and migration.

Altered Extracellular Matrix as an Alternative Risk Factor for Epileptogenicity in Brain Tumors

Seizures are one of the most common symptoms of brain tumors. The incidence of seizures differs among brain tumor type, grade, location and size, but paediatric-type diffuse low-grade gliomas/glioneuronal tumors are often highly epileptogenic. The extracellular matrix (ECM) is known to play a role in epileptogenesis and tumorigenesis because it is involved in the (re)modelling of neuronal connections and cell-cell signaling. In this review, we discuss the epileptogenicity of brain tumors with a focus on tumor type, location, genetics and the role of the extracellular matrix. In addition to functional problems, epileptogenic tumors can lead to increased morbidity and mortality, stigmatization and life-long care. The health advantages can be major if the epileptogenic properties of brain tumors are better understood. Surgical resection is the most common treatment of epilepsy-associated tumors, but post-surgery seizure-freedom is not always achieved. Therefore, we also discuss potential novel therapies aiming to restore ECM function.

GFAPδ: A Promising Biomarker and Therapeutic Target in Glioblastoma

GFAPδ, the delta isoform of the glial fibrillary acidic protein, is mainly expressed in the subventricular zone of the brain, together with other neural stem cell markers like nestin. The authors of this paper were among the first that described in detail the expression of GFAPδ and its correlation with malignancy and invasiveness in cerebral astrocytoma. Later, several papers confirmed these findings, showing that the alternative splice variant GFAPδ is overexpressed in glioblastoma (CNS WHO grade 4) compared with lower grade gliomas. Other studies suggested that a high GFAPδ/α ratio is associated with a more malignant and invasive behavior of glioma cells. Moreover, the changing of GFAPδ/α ratio affects the expression of high-malignant genes. It is now suggested that discriminating between predominant GFAP isoforms, GFAPδ or GFAPα, is useful for assessing the malignancy state of astrocytoma, and may even contribute to the classification of gliomas. Therefore, the purpose of this paper is to review the literature with emphasize on the role of GFAPδ as a potential biomarker, and as a possible therapeutic target in glioblastoma.

Inhibition of ATP hydrolysis as a key regulator of temozolomide resistance and migratory phenotype of glioblastoma cells

Glioblastoma (GBM) is the most lethal among malignant gliomas. The tumor invasiveness and therapy-resistance are important clinical hallmarks. Growing evidence emphasizes the purinergic signaling contributing to tumor growth. Here we exposed a potential role of extracellular ATPase activity as a key regulator of temozolomide cytotoxicity and the migration process in GBM cells. The inhibition of ATP hydrolysis was able to improve the impact of temozolomide, causing arrest mainly in S and G2 phases of the cell cycle, leading M059J and U251 cells to apoptosis. In addition to eradicating GBM cells, ATP hydrolysis exhibited a potential to modulate the invasive phenotype and the expression of proteins involved in cell migration and epithelial-to-mesenchymal-like transition in a 3D culture model. Finally, we suggest the ATPase activity as a key target to decline temozolomide resistance and the migratory phenotype in GBM cells.

Using chimeric antigen receptor T-cell therapy to fight glioblastoma multiforme: past, present and future developments

Introduction

Glioblastoma multiforme (GBM) constitutes one of the deadliest tumors to afflict humans, although it is still considered an orphan disease. Despite testing multiple new and innovative therapies in ongoing clinical trials, the median survival for this type of malignancy is less than two years after initial diagnosis, regardless of therapy. One class of promising new therapies are chimeric antigen receptor T cells or CAR-T which have been shown to be very effective at treating refractory liquid tumors such as B-cell malignancies. However, CAR-T effectivity against solid tumors such as GBM has been limited thus far.

Methods

A Pubmed, Google Scholar, Directory of Open Access Journals, and Web of Science literature search using the terms chimeric antigen receptor or CAR-T, GBM, solid tumor immunotherapy, immunotherapy, and CAR-T combination was performed for publication dates between January 1987 and November 2021.

Results

In the current review, we present a comprehensive list of CAR-T cells developed to treat GBM, we describe new possible T-cell engineering strategies against GBM while presenting a short introductory history to the reader regarding the origin(s) of this cutting-edge therapy. We have also compiled a unique list of anti-GBM CAR-Ts with their specific protein sequences and their functions as well as an inventory of clinical trials involving CAR-T and GBM.

Conclusions

The aim of this review is to introduce the reader to the field of T-cell engineering using CAR-Ts to treat GBM and describe the obstacles that may need to be addressed in order to significantly delay the relentless growth of GBM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11060-021-03902-8.

Netrin-like domain of sFRP4, a Wnt antagonist inhibits stemness, metastatic and invasive properties by specifically blocking MMP-2 in cancer stem cells from human glioma cell line U87MG

Rapid proliferation, high stemness potential, high invasiveness and apoptotic evasion are the distinctive hallmarks of glioma malignancy. The dysregulation of the Wnt/β-catenin pathway is the key factor regulating glioma malignancy. Wnt antagonist, secreted frizzled-related protein 4 (sFRP4), which has a prominent pro-apoptotic role in glioma stem cells, has two functional domains, the netrin-like domain (NLD), and cysteine-rich domain (CRD) both of which contribute to apoptotic properties of the whole protein. However, there are no reports elucidating the specific effects of individual domains of sFRP4 in inhibiting the invasive properties of glioma. This study explores the efficacy of the domains of sFRP4 in inhibiting the key hallmarks of glioblastoma such as invasion, metastasis, and stemness. We overexpressed sFRP4 and its domains in the glioblastoma cell line, U87MG cells and observed that both CRD and NLD domains played prominent roles in attenuating cancer stem cell properties. Significantly, we could demonstrate for the first time that both NLD and CRD domains negatively impacted the key driver of metastasis and migration, the matrix metalloproteinase-2 (MMP-2). Mechanistically, compared to CRD, NLD domain suppressed MMP-2 mediated invasion more effectively in glioma cells as observed in matrigel invasion assay and a function-blocking antibody assay. Fluorescent matrix degradation assay further revealed that NLD reduces matrix degradation. NLD also significantly disrupted fibronectin assembly and decreased cell adhesion in another glioma cell line LN229. In conclusion, the NLD peptide of sFRP4 could be a potent short peptide therapeutic candidate for targeting MMP-2-mediated invasion in the highly malignant glioblastoma multiforme.

Caveolin-1, a Key Mediator Across Multiple Pathways in Glioblastoma and an Independent Negative Biomarker of Patient Survival

Glioblastoma (GB) remains an aggressive malignancy with an extremely poor prognosis. Discovering new candidate drug targets for GB remains an unmet medical need. Caveolin-1 (Cav-1) has been shown to act variously as both a tumour suppressor and tumour promoter in many cancers. The implications of Cav-1 expression in GB remains poorly understood. Using clinical and genomic databases we examined the relationship between tumour Cav-1 gene expression (including its spatial distribution) and clinical pathological parameters of the GB tumour and survival probability in a TCGA cohort (n=155) and CGGA cohort (n=220) of GB patients. High expression of Cav-1 represented a significant independent predictor of shortened survival (HR = 2.985, 5.1 vs 14.9 months) with a greater statistically significant impact in female patients and in the Proneural and Mesenchymal GB subtypes. High Cav-1 expression correlated with other factors associated with poor prognosis: IDH w/t status, high histological tumour grade and low KPS score. A total of 4879 differentially expressed genes (DEGs) in the GB tumour were found to correlate with Cav-1 expression (either positively or negatively). Pathway enrichment analysis highlighted an over-representation of these DEGs to certain biological pathways. Focusing on those that lie within a framework of epithelial to mesenchymal transition and tumour cell migration and invasion we identified 27 of these DEGs. We then examined the prognostic value of Cav-1 when used in combination with any of these 27 genes and identified a subset of combinations (with Cav-1) indicative of co-operative synergistic mechanisms of action. Overall, the work has confirmed Cav-1 can serve as an independent prognostic marker in GB, but also augment prognosis when used in combination with a panel of biomarkers or clinicopathologic parameters. Moreover, Cav-1 appears to be linked to many signalling entities within the GB tumour and as such this work begins to substantiate Cav-1 or its associated signalling partners as candidate target for GB new drug discovery.

Captopril inhibits Matrix Metalloproteinase-2 and extends survival as a temozolomide adjuvant in an intracranial gliosarcoma model

BACKGROUND

Captopril is a well-characterized, FDA-approved drug that has demonstrated promise as a repurposed oncology therapeutic. Captopril's known anti-cancer effects include inhibition of Matrix Metalloproteinase-2 (MMP-2), an endopeptidase which selectively breaks down the extracellular matrix to promote cell migration. MMP-2 is a known therapeutic target in gliomas, tumors with significant clinical need. Using an aggressive gliosarcoma model, we assessed captopril's effects on MMP-2 expression in vitro and in vivo as well as its efficacy as an adjuvant in combination therapy regimens in vivo.

METHODS

Following captopril treatment, MMP-2 protein expression and migratory capabilities of 9 L gliosarcoma cells were assessed in vitro via western blots and scratch wound assays, respectively. Rats were intracranially implanted with 9 L gliosarcoma tumors, and survival was assessed in the following groups: control; captopril (30 mg/kg/day); temozolomide (TMZ) (50 mg/kg/day), and captopril+TMZ. In vivo experiments were accompanied by immunohistochemistry for MMP-2 from brain tissue.

RESULTS

In vitro, captopril decreased MMP-2 protein expression and reduced migratory capacity in 9 L gliosarcoma cells. In a gliosarcoma animal model, captopril decreased MMP-2 protein expression and extended survival as a TMZ adjuvant relative to untreated controls, captopril monotherapy, and TMZ monotherapy groups (27.5 versus 14 (p < 0.001), 16 (p < 0.001), and 23 (p = 0.018) days, respectively).

CONCLUSIONS

Captopril decreases gliosarcoma cell migration, which may be mediated by reduction in MMP-2 protein expression. Captopril provided a survival advantage as a TMZ adjuvant in a rat intracranial gliosarcoma model. Captopril may represent a promising potential adjuvant to TMZ therapy in gliosarcoma as a modulator of the MMP-2 pathway.

miR-1258 Attenuates Tumorigenesis Through Targeting E2F1 to Inhibit PCNA and MMP2 Transcription in Glioblastoma

MicroRNAs are a group of endogenous small non-coding RNAs commonly dysregulated in tumorigenesis, including glioblastoma (GBM), the most malignant brain tumor with rapid proliferation, diffuse invasion, and therapeutic resistance. Accumulating evidence has manifested that miR-1258 exerts an inhibitory role in many human cancers. However, the expression pattern of miR-1258 and its potential function in GBM tumorigenesis remain unclear. In this study, we reported that miR-1258 expression decreased with the ascending pathological grade of glioma, which indicated an unfavorable prognosis of patients. Functional assays revealed an inhibitory effect of miR-1258 on malignant proliferation, therapeutic resistance, migration, and invasion of GBM in vitro. Moreover, xenograft models also suggested a repression effect of miR-1258 on gliomagenesis. Mechanistically, miR-1258 directly targeted E2F1 in 3’-untranslated regions and attenuated E2F1-mediated downstream gene PCNA and MMP2 transcriptions. Furthermore, restoration of E2F1 expression in GBM cells effectively rescued the tumor-suppressive effect of miR-1258. Our studies illustrated that miR-1258 functioned as a tumor suppressor in GBM by directly targeting E2F1, subsequently inhibiting PCNA and MMP2 transcriptions, which contributed to new potential targets for GBM therapy and other E2F1-driven cancers.

Dichotomy in Growth and Invasion from Low- to High-Grade Glioma Cellular Variants

Glial dysfunction outraging CNS plasticity and integrity results in one of the most dangerous cancers, namely glioma, featuring little median survival period and high recurrence. The hallmark properties of proliferation, invasion and angiogenesis with the infiltrated macrophages in glioma are expected to be tightly coupled or cross-linked, but not properly related so far. The present study is aimed to find a relationship between this featured quadrangle from lower to higher grades (HG) of post-operative glioma tissues and their invading subsets. Elevated Ki67-associated proliferation in lower grades (LG) was supported with VEGF dependent angiogenic maintenance which found a decrease unlikely in HG. In contrast, MMP 2 and 9-associated invasions augmented high in HG with the dominant presence of CD204⁺ M2 polarized macrophages and a general increase in global DNMT1-associated methylation. Marked differences found in ECM invading cellular subsets of HG showing high proliferative capacity indicating rationally for recurrence, contrasting the nature of gross tumor tissue of the same grade. Thus in LG, the neoplastic lesion is more inclined to its growth while in higher grade more disposed towards tissue wreckage in support with cellular environmental milieu whereas the cellular variants and subsets of invaded cells showed different trends. Therefore, some operational dichotomy or coupling among cellular variants in glioma is active in determining its low- to high-grade transition and aggressive progression.

Casein kinase 1 (CK1) promotes the proliferation and metastasis of glioma cells via the phosphatidylinositol 3 kinase-matrix metalloproteinase 2 (AKT-MMP2) pathway

Background

Glioma is a type of tumor that usually occurs in the adult central nervous system. Protein kinases have become important targets for oncotherapy since they are closely correlated with signal transduction. The role of the casein kinase 1 (CK1) gene in glioma remains to be fully elucidated.

Methods

The mRNA and protein expression of CK1 were analyzed by Realtime PCR, Western blot and immunohistochemistry. The cell behavior was assayed by MTT, Transwell and cell scratch methods. Cell cycle and cell apoptosis were performed by flow cytometer. Construction of stable cell line was completed by lentivirus infection. The nude mouse model was used for in vivo analysis on the role of CK1 by injecting the cells into subcutaneous tissue, tail vein and cerebral cortex. The prognostic role of CK1 in glioma was evaluated using Kaplan-Meier and Cox regression analyses.

Results

immunohistochemical staining demonstrated that the expression of CK1 in glioma samples was correlated with the grade of glioma. Survival analysis using Kaplan-Meier and multivariate analysis by Cox regression indicated that CK1 could be used as an independent prognostic marker for glioma. The methyl thiazolyl tetrazolium (MTT), transwell, and cell scratch assays demonstrated that the CK1 gene promoted cell proliferation and invasion through the phosphatidylinositol 3 kinase/matrix metalloproteinase 2 (AKT-MMP2) signaling pathway. In vivo experiments in mice also confirmed the ability of CK1 to enhance tumor proliferation and metastasis, with the metastatic site being the small intestine.

Conclusions

the expression of CK1 was correlated with glioma grade and patient survival and it may enhance glioma proliferation and metastasis via AKT-MMP2 pathway.

Nidogen-1 expression is associated with overall survival and temozolomide sensitivity in low-grade glioma patients

We investigated the prognostic significance of nidogen-1 (NID1) in glioma. Oncomine, GEPIA, UALCAN, CCGA database analyses showed that NID1 transcript levels were significantly upregulated in multiple cancer types, including gliomas. Quantitative RT-PCR analyses confirmed that NID1 expression was significantly upregulated in glioma tissues compared to paired adjacent normal brain tissue samples (n=9). NID1 silencing enhanced in vitro apoptosis and the temozolomide sensitivity of U251 and U87-MG glioma cells. Protein-protein interaction network analysis using the STRING and GeneMANIA databases showed that NID1 interacts with several extracellular matrix proteins. TIMER database analysis showed that NID1 expression in low-grade gliomas was associated with tumor infiltration of B cells, CD4⁺ and CD8⁺ T cells, macrophages, neutrophils, and dendritic cells. Kaplan-Meier survival curve analysis showed that low-grade gliomas patients with high NID1 expression were associated with shorter overall survival. However, NID1 expression was not associated with overall survival in glioblastoma multiforme patients. These findings demonstrate that NID1 expression in glioma tissues is associated with overall survival of low-grade glioma patients and temozolomide sensitivity. NID1 is thus a potential prognostic biomarker and therapeutic target in low-grade glioma patients.

miR-338-3p inhibits cell growth, invasion, and EMT process in neuroblastoma through targeting MMP-2

This study aimed to explore the regulatory mechanisms of miR-338-3p and matrix metalloproteinase-2 (MMP-2) in neuroblastoma. Putative target interaction regions of miR-338-3p on MMP-2 were predicted by miRcode and miRbase bioinformatics tools. Relative expression of miRNA-338-3p and MMP-2 in neuroblastoma tissues and GI-LI-N and SK-N-SH cells was determined by reverse transcription polymerase chain reaction experiment. Furthermore, the cell proliferation was determined by Cell Counting Kit-8 assay, the cell apoptosis rate was analyzed by flow cytometry assay, and the cell invasion was evaluated by transwell assay. miR-338-3p expression was downregulated, whereas MMP-2 expression was upregulated in metastasis tissue site compared to that in primary tissue site in total. Furthermore, miR-338-3p overexpression suppressed proliferation, invasion, and epithelial-mesenchymal transition (EMT) of neuroblastoma cells but promoted apoptosis, and the knockdown of MMP-2 triggered similar effects. Furthermore, MMP-2 was directly targeted by miR-338-3p, and overexpression of MMP-2 rescued the inhibitory effects of miR-338-3p on human neuroblastoma cell progression. Collectively, these data demonstrated that miR-338-3p could suppress cell growth, invasion, and EMT pathway and induce apoptosis in neuroblastoma cells by targeting MMP-2. MiR-338-3p sponged MMP-2 to regulate the PI3K/AKT pathway in human neuroblastoma cells.

The effects of chitosan-based materials on glioma: Recent advances in its applications for diagnosis and treatment

Glioma is known as the most common primary brain tumor occurring in adolescents and is considered as a lethal disease worldwide. Despite the advancements in presently available therapeutic approaches (i.e. radiation therapy and chemotherapy), the rate of amelioration in glioma patients is still low. In this regard, it seems that there is a need for reconsidering and enhancing current therapies and/or discovering novel therapeutic platforms. Chitosan is a natural polysaccharide with several beneficial characteristics, including biocompatibility, biodegradability, and low toxicity. Without causing toxic effects on healthy cells, chitosan nanoparticles are attractive targets in cancer therapy which lead to the sustained release and enhanced internalization of chemotherapeutic drugs as well as higher cytotoxicity for cancer cells. Hence, these properties turn it into a suitable candidate for the treatment of various cancers, including glioma. In the viewpoint of glioma, cancer inhibition is possible through targeting glioma-associated signaling pathways and molecules such as MMP-9, VEGF, TRAIL and nuclear factor-κB by chitosan and its derivatives. Moreover, it has been acknowledged that chitosan and its derivatives can be applied as a delivery system for carrying a diverse range of therapeutic agents to the tumor site. Besides the anti-glioma effects of chitosan and its derivatives, these molecules can be utilized for culturing glioma cancer cells; providing a better understanding of glioma pathogenesis. Furthermore, it is documented that 3D chitosan scaffolds are potential targets that offer advantageous drug screening platforms. Herein, we summarized the anti-glioma effects of chitosan and also its utilization as drug delivery systems in the treatment of glioma.

Dysregulation of the MMP/TIMP Proteolytic System in Subependymal Giant Cell Astrocytomas in Patients With Tuberous Sclerosis Complex: Modulation of MMP by MicroRNA-320d In Vitro

Tuberous sclerosis complex (TSC), a rare genetic disorder caused by a mutation in the TSC1 or TSC2 gene, is characterized by the growth of hamartomas in several organs. This includes the growth of low-grade brain tumors, known as subependymal giant cell astrocytomas (SEGA). Previous studies have shown differential expression of genes related to the extracellular matrix in SEGA. Matrix metalloproteinases (MMPs), and their tissue inhibitors (TIMPs) are responsible for remodeling the extracellular matrix and are associated with tumorigenesis. This study aimed to investigate the MMP/TIMP proteolytic system in SEGA and the regulation of MMPs by microRNAs, which are important post-transcriptional regulators of gene expression. We investigated the expression of MMPs and TIMPs using previously produced RNA-Sequencing data, real-time quantitative PCR and immunohistochemistry in TSC-SEGA samples and controls. We found altered expression of several MMPs and TIMPs in SEGA compared to controls. We identified the lowly expressed miR-320d in SEGA as a potential regulator of MMPs, which can decrease MMP2 expression in human fetal astrocyte cultures. This study provides evidence of a dysregulated MMP/TIMP proteolytic system in SEGA of which MMP2 could be rescued by microRNA-320d. Therefore, further elucidating microRNA-mediated MMP regulation may provide insights into SEGA pathogenesis and identify novel therapeutic targets.

The Evaluation of AREG, MMP-2, CHI3L1, GFAP, and OPN Serum Combined Value in Astrocytic Glioma Patients' Diagnosis and Prognosis

Gliomas account for approximately 70% of primary brain tumors in adults. Of all gliomas, grade IV astrocytoma, also called glioblastoma, has the poorest overall survival, with <5% of patients surviving five years after diagnosis. Due to the aggressiveness, lethal nature, and impaired surgical accessibility of the tumor, early diagnosis of the tumor and, in addition, prediction of the patient's survival time are important. We hypothesize that combining the protein level values of highly recognizable glioblastoma serum biomarkers could help to achieve higher specificity and sensitivity in predicting glioma patient outcome as compared to single markers. The aim of this study was to select the most promising astrocytoma patient overall survival prediction variables from five secretory proteins-glial fibrillary acidic protein (GFAP), matrix metalloproteinase-2 (MMP-2), chitinase 3-like 1 (CHI3L1), osteopontin (OPN), and amphiregulin (AREG)-combining them with routinely used tumor markers to create a Patient Survival Score calculation tool. The study group consisted of 70 astrocytoma patients and 31 healthy controls. We demonstrated that integrating serum CHI3L1 and OPN protein level values and tumor isocitrate dehydrogenase 1 IDH1 mutational status into one parameter could predict low-grade astrocytoma patients' two-year survival with 93.8% accuracy.

Nanotherapeutic Modulation of Human Neural Cells and Glioblastoma in Organoids and Monocultures

Inflammatory processes in the brain are orchestrated by microglia and astrocytes in response to activators such as pathogen-associated molecular patterns, danger-associated molecular patterns and some nanostructures. Microglia are the primary immune responders in the brain and initiate responses amplified by astrocytes through intercellular signaling. Intercellular communication between neural cells can be studied in cerebral organoids, co-cultures or in vivo. We used human cerebral organoids and glioblastoma co-cultures to study glia modulation by dendritic polyglycerol sulfate (dPGS). dPGS is an extensively studied nanostructure with inherent anti-inflammatory properties. Under inflammatory conditions, lipocalin-2 levels in astrocytes are markedly increased and indirectly enhanced by soluble factors released from hyperactive microglia. dPGS is an effective anti-inflammatory modulator of these markers. Our results show that dPGS can enter neural cells in cerebral organoids and glial cells in monocultures in a time-dependent manner. dPGS markedly reduces lipocalin-2 abundance in the neural cells. Glioblastoma tumoroids of astrocytic origin respond to activated microglia with enhanced invasiveness, whereas conditioned media from dPGS-treated microglia reduce tumoroid invasiveness. Considering that many nanostructures have only been tested in cancer cells and rodent models, experiments in human 3D cerebral organoids and co-cultures are complementary in vitro models to evaluate nanotherapeutics in the pre-clinical setting. Thoroughly characterized organoids and standardized procedures for their preparation are prerequisites to gain information of translational value in nanomedicine. This study provides data for a well-characterized dendrimer (dPGS) that modulates the activation state of human microglia implicated in brain tumor invasiveness.

Extracellular proteolysis in glioblastoma progression and therapeutics

Gliomas encompass highly invasive primary central nervous system (CNS) tumours of glial cell origin with an often-poor clinical prognosis. Of all gliomas, glioblastoma is the most aggressive form of primary brain cancer. Current treatments in glioblastoma are insufficient due to the invasive nature of brain tumour cells, which typically results in local tumour recurrence following treatment. The latter represents the most important cause of mortality in glioblastoma and underscores the necessity for an in-depth understanding of the underlying mechanisms. Interestingly, increased synthesis and secretion of several proteolytic enzymes within the tumour microenvironment, such as matrix metalloproteinases, lysosomal proteases, cathepsins and kallikreins for extracellular-matrix component degradation may play a major role in the aforementioned glioblastoma invasion mechanisms. These proteolytic networks are key players in establishing and maintaining a tumour microenvironment that promotes tumour cell survival, proliferation, and migration. Indeed, the targeted inhibition of these proteolytic enzymes has been a promisingly useful therapeutic strategy for glioblastoma management in both preclinical and clinical development. We hereby summarize current advances on the biology of the glioblastoma tumour microenvironment, with a particular emphasis on the role of proteolytic enzyme families in glioblastoma invasion and progression, as well as on their subsequent prognostic value as biomarkers and their therapeutic targeting in the era of precision medicine.

Naringenin Sensitizes Resistant C6 Glioma Cells with a Repressive Impact on the Migrating Ability

Background:

Glioma, the most common form of a malignant brain tumour is characterised by a poor prognosis, which is attributable to its resistance against current therapeutic approaches. Temozolomide (TMZ), a DNA alkylating agent, is the first-line drug for glioma treatment. Long-term treatment using TMZ was reported to culminate in the development of resistance with overexpression of multidrug resistance 1 gene coded protein P-glycoprotein, which in turn releases the drugs from the tumour cells.

Purpose:

Thus, to circumvent such resistance issues, the current study attempted to explore the effect of naringenin (a flavanone) with proven antiglial tumour potential, in mitigating the features of TMZ resistance.

Methods:

Colony-forming assay, invasion assay and scratch wound assay were performed among the groups, namely tumour control (C6), vehicle control (V), naringenin (NGEN)-treated, drug-resistant tumour cells (C6R), and drug resistance cells added with NGEN (C6R+NGEN), to examine the impact of NGEN on migration and invasion. The effect of NGEN on filopodia length and density during cell migration was also studied in addition to the matrix metalloproteinases (MMP-2 and MMP-9) and p-ERK levels.

Results and Conclusion:

NGEN and C6R+NGEN groups had shown significant reduction (P < .01) in length and density of filopodia, colony formation, invasion and wound healing. Further, NGEN could also modify the assessed protein levels (P < .001), which were involved in migration and invasion in sensitive and resistant cells. Our study had provided the first evidence on NGEN-induced enhanced sensitivity against TMZ resistance with profound influence as an antimigratory and anti-invasive agent.

Breaking through the glioblastoma micro-environment via extracellular vesicles

Glioblastoma (GBM) is the most common and most aggressive brain tumour. Prognosis remains poor, despite the combined treatment of radio- and chemotherapy following surgical removal. GBM cells coexist with normal non-neoplastic cells, including endothelial cells, astrocytes and immune cells, constituting a complex and dynamic tumour micro-environment (TME). Extracellular vesicles (EVs) provide a critical means of bidirectional inter-cellular communication in the TME. Through delivery of a diverse range of genomic, lipidomic and proteomic cargo to neighbouring and distant cells, EVs can alter the phenotype and function of the recipient cell. As such, EVs have demonstrated their role in promoting angiogenesis, immune suppression, invasion, migration, drug resistance and GBM recurrence. Moreover, EVs can reflect the phenotype of the cells within the TME. Thus, in conjunction with their accessibility in biofluids, they can potentially serve as a biomarker reservoir for patient prognosis, diagnosis and predictive therapeutic response as well as treatment follow-up. Furthermore, together with the ability of EVs to cross the blood-brain barrier undeterred and through the exploitation of their cargo, EVs may provide an effective mean of drug delivery to the target site. Unveiling the mechanisms by which EVs within the GBM TME are secreted and target recipient cells may offer an indispensable understanding of GBM that holds the potential to provide a better prognosis and overall quality of life for GBM patients.

Serglycin activates pro-tumorigenic signaling and controls glioblastoma cell stemness, differentiation and invasive potential

Despite the functional role of serglycin as an intracellular proteoglycan, a variety of malignant cells depends on its expression and constitutive secretion to advance their aggressive behavior. Serglycin arose to be a biomarker for glioblastoma, which is the deadliest and most treatment-resistant form of brain tumor, but its role in this disease is not fully elucidated. In our study we suppressed the endogenous levels of serglycin in LN-18 glioblastoma cells to decipher its involvement in their malignant phenotype. Serglycin suppressed LN-18 (LN-18shSRGN) glioblastoma cells underwent astrocytic differentiation characterized by induced expression of GFAP, SPARCL-1 and SNAIL, with simultaneous loss of their stemness capacity. In particular, LN-18shSRGN cells presented decreased expression of glioma stem cell-related genes and ALDH1 activity, accompanied by reduced colony formation ability. Moreover, the suppression of serglycin in LN-18shSRGN cells retarded the proliferative and migratory rate, the invasive potential in vitro and the tumor burden in vivo. The lack of serglycin in LN-18shSRGN cells was followed by G2 arrest, with subsequent reduction of the expression of cell-cycle regulators. LN-18shSRGN cells also exhibited impaired expression and activity of proteolytic enzymes such as MMPs, TIMPs and uPA, both in vitro and in vivo. Moreover, suppression of serglycin in LN-18shSRGN cells eliminated the activation of pro-tumorigenic signal transduction. Of note, LN-18shSRGN cells displayed lower expression and secretion levels of IL-6, IL-8 and CXCR-2. Concomitant, serglycin suppressed LN-18shSRGN cells demonstrated repressed phosphorylation of ERK1/2, p38, SRC and STAT-3, which together with PI3K/AKT and IL-8/CXCR-2 signaling control LN-18 glioblastoma cell aggressiveness. Collectively, the absence of serglycin favors an astrocytic fate switch and a less aggressive phenotype, characterized by loss of pluripotency, block of the cell cycle, reduced ability for ECM proteolysis and pro-tumorigenic signaling attenuation.

Retinal astrocytes transcriptome reveals Cyp1b1 regulates the expression of genes involved in cell adhesion and migration

Astrocytes (AC) are the most abundant cells in the central nervous system. In the retina, astrocytes play important roles in the development and integrity of the retinal neurovasculature. Astrocytes dysfunction contributes to pathogenesis of a variety of neurovascular diseases including diabetic retinopathy. Recent studies have demonstrated the expression of Cyp1b1 in the neurovascular cells of the central nervous system including AC. We recently showed retinal AC constitutively express Cyp1b1, and global Cyp1b1-deficiency (Cyp1b1-/-) attenuates retinal ischemia-mediated neovascularization in vivo and the pro-angiogenic activity of retinal vascular cells in vitro. We also demonstrated that Cyp1b1 expression is a key regulator of retinal AC function. However, the underlying mechanisms involved need further investigation. Here we determined changes in the transcriptome profiles of Cyp1b1+/+ and Cyp1b1-/- retinal AC by RNA sequencing. We identified 585 differentially expressed genes, whose pathway enrichment analysis revealed the most significant pathways impacted in Cyp1b1-/- AC. These genes included those of axon guidance, extracellular matrix proteins and their receptors, cancer, cell adhesion molecules, TGF-β signaling, and the focal adhesion modulation. The expression of a selected set of differentially expressed genes was confirmed by RT-qPCR analysis. To our knowledge, this is the first report of RNAseq investigation of the retinal AC transcriptome and the molecular pathways impacted by Cyp1b1 expression. These results demonstrated an important role for Cyp1b1 expression in the regulation of various retinal AC functions, which are important in neurovascular development and integrity.

4-Hydroxy-7-oxo-5-heptenoic acid lactone is a potent inducer of brain cancer cell invasiveness that may contribute to the failure of anti-angiogenic therapies

Previously, we discovered that free radical-induced oxidative fragmentation of the docosahexaenoate ester of 2-lysophosphatidylcholine produces 4-hydroxy-7-oxo-5-heptenoic acid (HOHA) lactone that, in turn, promotes the migration and invasion of endothelial cells. This suggested that HOHA lactone might similarly promote migration and invasion of glioblastoma multiformae (GBM) brain cancer stem cells (CSCs). A bioinformatics analysis of clinical cancer genomic data revealed that matrix metalloproteinase (MMP)1 and three markers of oxidative stress - superoxide dismutase 2, NADPH oxidase 4, and carbonic anhydrase 9 - are upregulated in human mesenchymal GBM cancer tissue, and that MMP1 is positively correlated to all three of these oxidative stress markers. In addition, elevated levels of MMP1 are indicative of GBM invasion, while low levels of MMP1 indicate survival. We also explored the hypothesis that the transition from the proneural to the more aggressive mesenchymal phenotype, e.g., after treatment with an anti-angiogenic therapy, is promoted by the effects of lipid oxidation products on GBM CSCs. We found that low micromolar concentrations of HOHA lactone increase the cell migration velocity of cultured GBM CSCs, and induce the expression of MMP1 and two protein biomarkers of the proneural to mesenchymal transition (PMT): p65 NF-κβ and vimentin. Exposure of cultured GBM CSCs to HOHA lactone causes an increase in phosphorylation of mitogen-activated protein kinases and Akt kinases that are dependent on both protease-activated receptor 1 (PAR1) and MMP1 activity. We conclude that HOHA lactone promotes the PMT in GBM through the activation of PAR1 and MMP1. This contributes to a fatal flaw in antiangiogenic, chemo, and radiation therapies: they promote oxidative stress and the generation of HOHA lactone in the tumor that fosters a change from the proliferative proneural to the migratory mesenchymal GBM CSC phenotype that seeds new tumor growth. Inhibition of PAR1 and HOHA lactone are potential new therapeutic targets for impeding GBM tumor recurrence.

The effects of melatonin on signaling pathways and molecules involved in glioma

Glioblastoma is one of the most common brain tumors with high invasion and malignancy. Despite extensive research in this area and the use of new and advanced therapies, the survival rate in this disease is very low. In addition, resistance to treatment has also been observed in this disease. One of the reasons for rapid progression and failure in treatment for this disease is the presence of a class of cells with high proliferation and high differentiation, a class called glioblastoma stem-like cells shown as being the source of glioblastoma tumors. It has been reported that several oncogenes are expressed in this disease. One important issue in recognizing the pathogenesis of this disease, and which could improve the treatment process, is the identification of involved oncogenes as well as molecules that affect the reduction of the expression of these oncogenes. Melatonin regulates the biological rhythm and inhibits the proliferation of malignant glioma cells due to antioxidant and anti-apoptotic effects. Melatonin has been considered in biological processes and in signaling pathways involved in the development of glioma. The aim of this review is to investigate the effects of melatonin on signaling pathways and molecules involved in the progression of glioma.

Increased expression of MMP-2 and MMP-9 indicates poor prognosis in glioma recurrence

The main characteristic of glioma is recurrence, even after intensive multidisciplinary treatment. Studies show that enhanced invasive ability will increase the ability of tumor cells to escape from the primary tumor mass, which is a key factor contributing to tumor relapse and recurrence. In this study, we assessed the expression of MMP-2, MMP-9, two important matrix metallopeptidases that increase the invasive ability of glioma, and their suppressors, TIMP-1, TIMP-2 in glioma tissues from primary and recurrent glioma patients by immunohistochemistry. Glioma cells and nude mice were used for in vitro and in vivo studies. Results showed that the expression of MMP-2 and MMP-9 in recurrent gliomas were significantly higher than those in primary gliomas (P = 3.075 × 10^{-11, P = 1.510 × 10-5}, respectively). We also found that radiotherapy increased the expression of MMP-9, but had no effect on MMP-2 and TIMP-1/2. With glioma cell line U251, we found that irradiation increased the expression of MMP-9 in vitro. Tumor tissues from an orthotopic xenograft model showed that after irradiation treatment, the expression of MMP-9 increased significantly in vivo. We also found that knocking down MMP-9 decreased irradiation-induced invasion obviously. Above all, we concluded that higher expressions of MMP-2/-9 indicate poor prognosis in glioma recurrence. The increased expression of MMP-9 after radiotherapy suggests that MMP-9 might be an important target in the radiosensitization of glioma.

GFAP alternative splicing regulates glioma cell-ECM interaction in a DUSP4-dependent manner

Gliomas are the most common primary brain tumors. Their highly invasive character and the heterogeneity of active oncogenic pathways within single tumors complicate the development of curative therapies and cause poor patient prognosis. Glioma cells express the intermediate filament protein glial fibrillary acidic protein (GFAP), and the level of its alternative splice variant GFAP-δ, relative to its canonical splice variant GFAP-α, is higher in grade IV compared with lower-grade and lower malignant glioma. In this study we show that a high GFAP-δ/α ratio induces the expression of the dual-specificity phosphatase 4 (DUSP4) in focal adhesions. By focusing on pathways up- and downstream of DUSP4 that are involved in the cell-extracellular matrix interaction, we show that a high GFAP-δ/α ratio equips glioma cells to better invade the brain. This study supports the hypothesis that glioma cells with a high GFAP-δ/α ratio are highly invasive and more malignant cells, thus making GFAP alternative splicing a potential therapeutic target.-Van Bodegraven, E. J., van Asperen, J. V., Sluijs, J. A., van Deursen, C. B. J., van Strien, M. E., Stassen, O. M. J. A., Robe, P. A. J., Hol, E. M. GFAP alternative splicing regulates glioma cell-ECM interaction in a DUSP4-dependent manner.

Emerging Pathogenic and Prognostic Significance of Paired Box 3 (PAX3) Protein in Adult Gliomas

Gliomas present the most common type of brain tumors in adults, characterized by high morbidity and mortality. In search of potential molecular targets, members of paired box (PAX) family have been found expressed in neural crest cells, regulating their proliferation, apoptosis, migration and differentiation. Recently, PAX3 overexpression has been implicated in glioma tumorigenesis by enhancing proliferation, increasing invasiveness and inducing resistance to apoptosis of glioma cells, while maintaining brain glioma stem cells (BGSCs) stemness. Although the oncogenic potential of PAX3 in gliomas is still under investigation, experimental evidence suggests that PAX3 function is mainly mediated through the canonical and non-canonical Wnt signaling pathway as well as through its interaction with GFAP and p53 proteins. In addition, PAX3 may contribute to the chemoresistance of glioma cells and modulates the effectiveness of novel experimental therapies. Further evidence indicates that PAX3 may represent a novel diagnostic and prognostic biomarker for gliomas, facilitating personalized treatment. This review addresses the emerging role of PAX3 in glioma diagnosis, prognosis and treatment, aiming to shed more light on the underlying molecular mechanisms that could lead to more effective treatment approaches.

Clinicohistopathological implications of MMP/VEGF expression in retinoblastoma: a combined meta-analysis and bioinformatics analysis

BACKGROUND

No in-depth systematic evidence is available for assessing retinoblastoma malignancy and eligibility for subsequent treatment.

METHODS

The Cochrane Library, EMBASE, PubMed, Web of Science, and China Biology Medicine databases were searched, and 16 studies comprising 718 retinoblastoma patients were included. Pooled odds ratios (ORs) and summary correlation coefficients (r) with 95% confidence intervals (CIs) in random-effects, fixed-effects or quality-effects models were calculated using Review Manager 5.3 and MetaXL. GO functional annotation and KEGG pathway analysis were performed using the GO and STRING databases.

RESULTS

We observed significant associations between high levels of MMP-1 (OR, 4.21; 95% CI 1.86-9.54), MMP-2 (OR, 11.18; 95% CI 4.26-29.30), MMP-9 (OR, 10.41, 95% CI 4.26-25.47), and VEGF (OR, 8.09; 95% CI 4.03-16.20) with tumor invasion; high levels of MMP-1 (OR, 3.58; 95% CI 1.48-8.71), MMP-2 (OR, 2.96; 95% CI 1.32-6.64), MMP-9 (OR, 5.49; 95% CI 3.55-8.48) and VEGF (OR, 5.30; 95% CI 2.93-9.60) with poor differentiation; and overexpression of MMP-9 (OR, 5.17; 95% CI 2.85-9.38) with advanced clinical stages. Moreover, MMP-9 and VEGF expression were positively correlated (r, 0.61; 95% CI 0.38-0.77). Multiple GO terms were enriched associated with MMP-1, MMP-2, MMP-9 and VEGF, and they are closely associated with pathways, proteoglycans and microRNAs related to cancer.

CONCLUSIONS

MMP-1, MMP-2, MMP-9 and VEGF play important roles in the development and progression of retinoblastoma. High levels of MMP-1, MMP-2, MMP-9 and VEGF are credible implications for increased malignancy, thus the need for more aggressive treatments.

[The distribution of matrix metalloproteinases and their tissue inhibitors in the brain vascular bed exposed to chronic tobacco smoke]

AIM

To study the distribution of MMP-2 and MMP-9 and their inhibitors (TIMP-2 and TIMP-1 respectively) in the brain vascular bed of rats exposed to chronic tobacco smoke.

MATERIAL AND METHODS

Localization and expression of MMP-2, MMP-9, TIMP-2 and TIMP-1 in the pial branches (I-V order vessels), intracerebral arteries and capillaries of rats exposed to tobacco smoke were studied for 36 weeks. The level of enzymatic activity was assessed by the relative quantity of enzymopositive arteries and amount of fragments per 1 mm2 and rate of immunohistochemical reaction. Specific capillary density per mm2 of brain tissue and optical density of the immunohistochemical product were calculated.

RESULTS

MMP-2 and TIMP-2 were found in all segments of the arterial course in control animals. In rats exposed to tobacco smoking, the expression of MMP-2 increased only in intracerebral arteries and capillaries while TIMP-2 level decreased. MMP-9 and TIMP-1 were noted only in single vessels, mainly small pial and intracerebral arteries, in intact animals. In rats exposed to tobacco smoke, MMP-9 expression significantly increased in all segments of the arterial course whereas the increase in TIMP-1 was observed mainly in large pial arteries.

CONCLUSION

In physiological conditions, the dynamic balance between MMP-2 and TIMP-2 maintains basic tissue metabolism. Products of tobacco combustion are inductors of the inducible MMP-9 which promotes morphofunctional changes. The imbalance in MMP-9 - TIMP-1 system causes the degradation of extracellular matrix in different segments of the brain arterial course promoting the development of cerebral dysfunction.

Inflammatory activation of microglia by Staphylococcus aureus caused phenotypic alterations and affected glioblastoma growth

As the most common type of tumour in brain, glioma has a high rate of morbidity and mortality and easily penetrates the surrounding normal brain parenchyma. The immunosuppressive microenvironment, which is similar to that in other neoplasms, is believed to participate in the tumorigenesis of glioma. Thus, many experts are seeking to exploit microenvironment as a therapeutic target. In the present study, we focused on microglia polarization to investigate the anti-glioma response of microglia inflammatory activation by Staphylococcus aureus in vitro and in vivo. First, we found that intratumor injection of S. aureus delayed glioma growth in C57/BL6 mice. Then, we showed that inflammatory microglia activated by S. aureus inhibited glioma cell proliferation, migration, and invasion. This inhibition was likely related to the phenotypic switch observed in microglia. In intracranial tumour models, the microglia activated by S. aureus exerted antitumour efficacy and prolonged animal survival. Taken together, our results suggest that microglia activated by S. aureus have antitumour efficacy, which may be a potential therapeutic agent for glioma. SIGNIFICANCE OF THE STUDY: In this study, we mainly demonstrated the antitumour efficacy of microglia after activated by S. aureus. Firstly, we found that intratumor injection of S. aureus inhibited the tumour growth in intracranial orthotopic glioma model. In addition, we found that the microglia around the glioma may exert antitumour efficacy, and its phenotype may be altered by stimulation of S. aureus. Our data manifested that S. aureus did not directly suppress cell proliferative, migration, and invasion capacity, but by activating microglia. And in mice GL261 GBMs, injection of microglia after cocultured with S. aureus inhibited tumour growth and prolonged animal survival.

High filamin-C expression predicts enhanced invasiveness and poor outcome in glioblastoma multiforme

Background

Glioblastoma multiforme (GBM), the most common brain malignancy in adults, is generally aggressive and incurable, even with multiple treatment modalities and agents. Filamins (FLNs) are a group of actin-binding proteins that regulate the actin cytoskeleton in cells. However, the role of FLNs in malignancies—particularly in GBM—is unclear.

Methods

The relation between FLNC expression and overall survival in GBM was evaluated by the Kaplan−Meier analysis using GBM patients from the Kagoshima University Hospital (n = 90) and data from the Cancer Genome Atlas (TCGA) (n = 153). To assess FLNC function in GBM, cell migration and invasion were examined with Transwell and Matrigel invasion assays using FLNC-overexpressing U251MG and LN299 GBM cells, and ShRNA-mediated FLNC knocked-down KNS81 and U87MG cells. The gelatin zymography assay was used to estimate matrix metalloproteinase (MMP) 2 activity.

Results

In silico analysis of GBM patient data from TCGA and immunohistochemical analyses of clinical GBM specimens revealed that increased FLNC expression was associated with poor patient prognosis. FLNC overexpression in GBM cell lines was positively correlated with enhanced invasiveness, but not migration, and was accompanied by upregulation of MMP2.

Conclusions

FLNC is a potential therapeutic target and biomarker for GBM progression.

Naringenin inhibited migration and invasion of glioblastoma cells through multiple mechanisms

Glioblastoma (GBM) is the most mortality brain cancer in the world. Due to high invasion and drug resistance cause the poor prognosis of GBM. Naringenin, an ingredient of citrus, exhibits many cellular functions such as antioxidant, anti-inflammation, and anticancer. Naringenin inhibits the migration of bladder and lung cancer via modulation of MMP-2 and/or MMP-9 activities, Naringenin inhibits migration and trigger apoptosis in gastric cancer cells through downregulation of AKT pathway. However, the effects of naringenin in GBM still remain to be elucidated. In this study, we reveal the molecular mechanisms of naringenin in the inhibition of migration and invasion in GBM. No overt alternation of cell proliferation was found in of GBM 8901 cells treated with different concentration of naringenin. Slight decreased cell viability was found in GBM 8401 cell treated with 200 and 300 μM naringenin. Significant reduction of migration and invasion as assayed by Boyden chamber analysis was found in of GBM cells treated with 100, 200, and 300 μM naringenin. Zymography analysis also revealed that the activities of MMP-2 and MMP-9 of GBM cells were significantly inhibited in response to 100, 200, or 300 μM naringenin treatment. Proteins of MMP-2 and MMP-9 were downregulated in naringenin treated GBM cells. In addition, naringenin also attenuated the activities of ERK and p38. Naringenin decreased mesenchymal markers (snail and slug) expression as revealed by Western blot analysis. Taken together, our findings indicated that naringenin eliminated the migration and invasion of GBM cells through multiple mechanisms including inhibition of MMPs, ERK, and p38 activities and modulation of EMT markers. Our results also suggested that naringenin may be a potential agent to prevent metastasis of GBM.

MMP-2 expression and correlation with pathology and MRI of glioma

The expression of matrix metalloproteinase-2 (MMP-2) in brain glioma and its correlation with patients' clinicopathological characteristics and magnetic resonance imaging (MRI) features were investigated. A total of 104 patients with brain glioma admitted and treated in the First Affiliated Hospital of Anhui Medical University from June 2010 to September 2014 were randomly enrolled. MRI examination was performed before operation. Immunohistochemistry (IHC) was used to detect the expression levels of MMP-2 in brain glioma tissues and paired normal brain tissues after operation and to analyze the associations of MMP-2 expression with the clinicopathological characteristics of brain glioma and survival time of patients. The relationship between MMP-2 expression and preoperative MRI features of glioma was analyzed. The positive rate of MMP-2 expression in brain glioma was 73.08% (76/104), while that in paired normal brain tissues was only 12.5% (13/104), obviously lower than that in brain glioma tissues (P<0.05). The MMP-2 expression in the body of glioma was not related to the patients' sex, age, tumor location and pathological type (P>0.05), but there was a significant correlation with the tumor diameter and pathological grade of the patients (P<0.05). Analysis by Cox model suggested that tumor diameter, pathological grade and MMP-2 were independent prognostic factors for glioma (P<0.05). The overall survival (OS) of patients in the positive MMP-2 expression group was 16.4 months, while the OS in the negative MMP-2 expression group was 20.16 months, and the difference between the two groups was statistically significant (P<0.05). The positive expression of MMP-2 in glioma was closely related to the uniformity of MRI signal for tumor, tumor diameter, severity of peritumoral edema, degree of enhancement and pathological grade of tumor (P<0.05). MMP-2 is highly expressed in brain glioma, and it is a negative factor for prognosis. Therefore, the MRI manifestations of glioma can reflect to some extent the intensity of MMP-2 expression.

Vicenin-2: a potential radiosensitizer of non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is a major form of cancer and is resistant to chemo- and radio-therapy. Vicenin-2 (VCN-2) is a flavonoid obtained from Ocimum sanctum L. and it has been reported to have radioprotective and anti-cancer properties. This study was conducted to check for the radiosensitizing potential of VCN-2 in the NSCLC cell line, NCI-H23. NCI-H23 cells were exposed to VCN-2 singularly, and to X-rays with and without prior VCN-2 treatment. Cytotoxicity assay, cell proliferation assay, caspase-3 activity assay, DNA fragmentation assay and Western blotting for Rad50, MMP-2 and p21 were performed to investigate the radiosensitizing properties of VCN-2. Fibroblast survival assay was performed using HEK293T cells to check for any adverse effects of VCN-2 on normal fibroblast cell line. VCN-2 singularly and in combination with radiation reduced the surviving cancer cells, increased caspase-3 activity, increased DNA fragmentation, increased the levels of Rad50 and lowered levels of MMP-2 and p21 proteins while being non-toxic and radioprotective to the fibroblast cells. VCN-2 showed a potent radiosensitizing property while also showing a chemotherapeutic property against NSCLC cell line NCI-H23.

[High expression of MMP20 may be a potential prognostic factor for poor outcomes of patients with endometrial carcinoma]

OBJECTIVE

To explore the expression of MMP20 in endometrial carcinoma and its clinical significance.

METHODS

Bioinformatics analysis was used to explore the correlation of MMP20 expression with the prognosis of the patients with endometrial carcinoma. We collected 21 pairs of fresh endometrial carcinoma and adjacent endometrial tissues to detect the expression of MMP20 mRNA using real-time PCR. We also examined MMP20 protein expressions in 134 paraffin-embedded endometrial carcinoma tissues and 34 paraffin-embedded endometrial tissues using immunohistochemistry. The correlation of MMP20 expression with the clinicopathological features and prognosis of the patients were analyzed.

RESULTS

Based on TCGA database analysis, the patients with endometrial carcinoma showing an increased MMP20 mRNA expression had a significantly poorer prognosis than those with a low MMP20 mRNA expression (P=0.00065). Real-time PCR analysis and immunohistochemistry confirmed the up-regulated expressions of MMP20 at both the mRNA (P=0.0062) and protein (P=0.005) levels in endometrial carcinoma tissues compared to the adjacent endometrial tissues. An elevated MMP20 protein expression was positively associated with FIGO stage of endometrial carcinoma (P=0.014) and inversely correlated with the survival time of the patients (P=0.019). The Cox regression model analysis showed that an increased MMP20 expression was an independent predictor of a poor prognosis of the patients with endometrial carcinoma (P=0.067).

CONCLUSIONS

High expression of MMP20 is a potential prognostic factor for poor outcomes of patients with endometrial carcinoma.

Fabrication and Characterization of Chitosan-Hyaluronic Acid Scaffolds with Varying Stiffness for Glioblastoma Cell Culture

The invasive and recurrent nature of glioblastoma multiforme (GBM) is linked to a small subpopulation of cancer cells, which are self-renewing, resistant to standard treatment regimens, and induce formation of new tumors. Matrix stiffness is implicated in the regulation of cell proliferation, drug resistance, and reversion to a more invasive phenotype. Therefore, understanding the relationship between matrix stiffness and tumor cell behavior is vital to develop appropriate in vitro tumor models. Here, chitosan-hyaluronic acid (CHA) polyelectrolyte complex scaffolds are fabricated with statistically significant stiffness variances to characterize the effect of scaffold stiffness on morphology, proliferation, drug resistance, and gene expression in human glioblastoma cells (U-87 MG). All scaffolds support GBM proliferation over a 12-day culture period, yet larger spheroids are observed in scaffolds with higher stiffness. Additionally, GBM cells cultured in stiffer CHA scaffolds prove significantly more resistant to the common chemotherapeutic temozolomide. Moreover, the stiffer 8% CHA scaffolds exhibit an increase in expression of drug resistance and invasion related genes compared to 2D culture. CHA scaffolds present a tunable microenvironment for enhanced tumor cell malignancy and may provide a valuable in vitro microenvironment for studying tumor progression and screening anticancer therapies.

MMP2 is associated with glioma malignancy and patient outcome

Gliomas are fast growing and usually manifest in an aggressive infiltrative model. MMP2 overexpression is associated with brain tumor malignancy and metastasis formation. The aim of this study was to investigate the influence of MMP2 on glioma formation and clinical outcomes by performing analysis at the DNA, RNA, and protein levels. Methylation status and mRNA level were evaluated in 162 samples; the MMP2 protein level was analyzed in 28 patient preoperative and postoperative blood samples using protein microarray analysis and conventional ELISA. The MMP2 MSP analysis revealed a gradually increasing gene promoter demethylation frequency, and the Kaplan-Meier analysis showed that the methylated gene promoter is related to longer overall survival (Log-rank test X ² = 12.508, df = 1, P < 0.0001). Relative mRNA expression was significantly downregulated when the promoter was methylated. Pairwise comparison analysis showed statistically significant (Mann-Whitney test, P < 0.05) differences in the MMP2 expression median when comparing different glioma grades. The Kaplan-Meier analysis revealed that low MMP2 expression was associated with better survival (Log-rank test X ² = 7.732, df = 1, P = 0.005). At the protein level, MMP2 expression in patient sera showed no differences between malignancy grades and patient preoperative and postoperative states, while the ELISA assay showed the tendency of accumulating MMP2 protein in higher malignancy patient sera samples. The Kaplan-Meier analysis showed the tendency of having a shorter survival time with a higher MMP2 protein level in patient sera. MMP2 has a significant role in glioma pathogenesis and could be used as a potential molecular marker for tumor progression.

Co-expression of TIMP-1 and its cell surface binding partner CD63 in glioblastomas

Background

We have previously identified tissue inhibitor of metalloproteinases-1 (TIMP-1) as a prognostic marker in glioblastomas. TIMP-1 has been associated with chemotherapy resistance, and CD63, a known TIMP-1-binding protein, has been suggested to be responsible for this effect. The aim of this study was to assess CD63 expression in astrocytomas focusing on the prognostic potential of CD63 alone and in combination with TIMP-1.

Methods

CD63 expression was investigated immunohistochemically in a cohort of 111 astrocytomas and correlated to tumor grade and overall survival by semi-quantitative scoring. CD63 expression in tumor-associated microglia/macrophages was examined by double-immunofluorescence with ionized calcium-binding adapter molecule 1 (Iba1). The association between CD63 and TIMP-1 was investigated using previously obtained TIMP-1 data from our astrocytoma cohort. Cellular co-expression of TIMP-1 and CD63 as well as TIMP-1 and the tumor stem cell-related markers CD133 and Sox2 was investigated with immunofluorescence. TIMP-1 and CD63 protein interaction was detected by an oligonucleotide-based proximity ligation assay and verified using co-immunoprecipitation.

Results

The expression of CD63 was widely distributed in astrocytomas with a significantly increased level in glioblastomas. CD63 levels did not significantly correlate with patient survival at a protein level, and CD63 did not augment the prognostic significance of TIMP-1. Up to 38% of the CD63+ cells expressed Iba1; however, Iba1 did not appear to impact the prognostic value of CD63. A significant correlation was found between TIMP-1 and CD63, and the TIMP-1 and CD63 proteins were co-expressed at the cellular level and located in close molecular proximity, suggesting that TIMP-1 and CD63 could be co-players in glioblastomas. Some TIMP-1+ cells expressed CD133 and Sox2.

Conclusion

The present study suggests that CD63 is highly expressed in glioblastomas and that TIMP-1 and CD63 interact. CD63 does not add to the prognostic value of TIMP-1. Co-expression of TIMP-1 and stem cell markers as well as the wide expression of CD63 might suggest a role for TIMP-1 and CD63 in glioblastoma stemness.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4179-y) contains supplementary material, which is available to authorized users.