Concurrent Expression of VEGF-C and Neuropilin-2 Is Correlated with Poor Prognosis in Glioblastoma

Vascular endothelial growth factor-C modulates cortical NMDA receptor activity in cortical lesions of young patients and rat model with focal cortical dysplasia

Emergence of dysmorphic neurons is the primary pathology in focal cortical dysplasia (FCD) associated pediatric intractable epilepsy; however, the etiologies related to the development and function of dysmorphic neurons are not fully understood. Our previous studies revealed that the expression of vascular endothelial growth factor-C (VEGF-C) and corresponding receptors VEGFR-2, VEGFR-3 was increased in the epileptic lesions of patients with tuberous sclerosis complex or mesial temporal lobe epilepsy. Here, we showed that the expression of VEGF-C, VEGFR-2, and VEGFR-3 was increased at both mRNA and protein levels in patients with cortical lesions of type I, IIa, and IIb FCD. The immunoreactivity of VEGF-C, VEGFR-2 and VEGFR-3 was located in the micro-columnar neurons in FCD type I lesions, dysplastic neurons (DNs) in FCD type IIa lesions, balloon cells (BCs) and astrocytes in FCD type IIb lesions. Additionally, the amplitude of evoked-EPSCs (eEPSC) mediated by NMDA receptor, the ratio of NMDA receptor- and AMPA receptor-mediated eEPSC were increased in the dysmorphic neurons of FCD rats established by prenatal X-ray radiation. Furthermore, NMDA receptor mediated current in dysmorphic neurons was further potentiated by exogenous administration of VEGF-C, however, could be antagonized by ki8751, the blocker of VEGFR-2. These results suggest that VEGF-C system participate in the pathogenesis of cortical lesions in patients with FCD in association with modulating NMDA receptor-mediated currents.

Role of Neuropilin-2-mediated signaling axis in cancer progression and therapy resistance

Neuropilins (NRPs) are transmembrane proteins involved in vascular and nervous system development by regulating angiogenesis and axon guidance cues. Several published reports have established their role in tumorigenesis. NRPs are detectable in tumor cells of several cancer types and participate in cancer progression. NRP2 is also expressed in endothelial and immune cells in the tumor microenvironment and promotes functions such as lymphangiogenesis and immune suppression important for cancer progression. In this review, we have taken a comprehensive approach to discussing various aspects of NRP2-signaling in cancer, including its regulation, functional significance in cancer progression, and how we could utilize our current knowledge to advance the studies and target NRP2 to develop effective cancer therapies.

Neuropilin-1: A Key Protein to Consider in the Progression of Pediatric Brain Tumors

Neuropilins are transmembrane glycoproteins that play important roles in cardiovascular and neuronal development, as well as in immunological system regulations. NRP1 functions as a co-receptor, binding numerous ligands, such as SEMA 3 or VEGF and, by doing so, reinforcing their signaling pathways and can also interface with the cytoplasmic protein synectin. NRP1 is expressed in many cancers, such as brain cancers, and is associated with poor prognosis. The challenge today for patients with pediatric brain tumors is to improve their survival rate while minimizing the toxicity of current treatments. The aim of this review is to highlight the involvement of NRP1 in pediatric brain cancers, focusing essentially on the roles of NRP1 in cancer stem cells and in the regulation of the immune system. For this purpose, recent literature and tumor databases were analyzed to show correlations between NRP1 and CD15 (a stem cancer cells marker), and between NRP1 and PDL1, for various pediatric brain tumors, such as high- and low-grade gliomas, medulloblastomas, and ependymomas. Finally, this review suggests a relevant role for NRP1 in pediatric brain tumors progression and identifies it as a potential diagnostic or therapeutic target to improve survival and life quality of these young patients.

Semaphorin 3F Serves as a Tumor Suppressor in Esophageal Squamous Cell Carcinoma and is Associated With Lymph Node Metastasis in Disease Progression

Background:

Esophageal squamous cell carcinoma is one of the leading aggressive malignancies with high mortality. Semaphorin 3F has been reported to be involved in lymphangiogenesis by interacting the vascular endothelial growth factor C/neuropilin 2 axis. This study aimed to assess the clinical and functional role of semaphorin 3F and preliminarily evaluate the relationship between semaphorin 3F and lymph node metastasis in esophageal squamous cell carcinoma.

Methods:

The messenger RNA expression of semaphorin 3F was analyzed using quantitative real-time polymerase chain reaction. The expression differences of semaphorin 3F between patients having esophageal squamous cell carcinoma with and without lymph node metastasis were assessed, and the correlation of semaphorin 3F with vascular endothelial growth factor C and neuropilin 2 was estimated. The prognostic value of semaphorin 3F was evaluated using Kaplan-Meier survival curves and Cox regression analysis. Gain- and loss-functional cell experiments were performed to explore the biological function of semaphorin 3F, vascular endothelial growth factor C, and neuropilin 2.

Results:

The messenger RNA expression of semaphorin 3F was reduced in esophageal squamous cell carcinoma tissues compared with normal tissues, and lower semaphorin 3F expression was observed in patients having esophageal squamous cell carcinoma with positive lymph node metastasis. Semaphorin 3F expression was associated with lymph node metastasis and negatively correlated with vascular endothelial growth factor C and neuropilin 2. Lower semaphorin 3F expression was related to a poor overall survival of esophageal squamous cell carcinoma and served as an independent prognostic indicator. In esophageal squamous cell carcinoma cells, semaphorin 3F messenger RNA expression was also decreased compared with normal cells, and the overexpression of semaphorin 3F could significantly inhibit cell proliferation, migration, and invasion. The downregulation of vascular endothelial growth factor C and neuropilin 2 could inhibit cell proliferation, migration, and invasion of esophageal squamous cell carcinoma cells.

Conclusion:

All data indicate that semaphorin 3F serves as a potential prognostic biomarker and tumor suppressor of esophageal squamous cell carcinoma and may be involved in the lymph node metastasis development through regulating neuropilin 2.

New insights into the role of co-receptor neuropilins in tumour angiogenesis and lymphangiogenesis and targeted therapy strategies

Local tumour sites lead to pathological angiogenesis and lymphangiogenesis due to malignant conditions such as hypoxia. Although VEGF and VEGFR are considered to be the main anti-tumour treatment targets, the problems of limited efficacy and observable side effects of some drugs relevant to this target still remain to be solved. Therefore, it is necessary to identify new therapeutic targets for angiogenesis or lymphangiogenesis. The neuropilin family is a class of single transmembrane glycoprotein receptors, including neuropilin1 (NRP1) and neuropilin2 (NRP2), which could act as co-receptors of VEGFA-165 and VEGFC and play a key role in promoting tumour proliferation, invasion and metastasis. In this review, we introduced the schematic diagram to visually reveal the function of NRP1 and NRP2 in enhancing the binding affinity of VEGFR2 to VEGFA-165 and VEGFR3 to VEGFC, respectively. We also discussed the signalling pathways that depend on the co-receptors NRP1 and NRP2 and some existing targeted therapeutic strategies, such as monoclonal antibodies, targeted peptides, microRNAs and small molecule inhibitors. It will contribute a vital foundation for the future research and development of new drugs targeting NRPs. HIGHLIGHTS NRP1 acts as a co-receptor with VEGFR2 and the pro-angiogenic factor VEGFA-165 to up-regulate tumour angiogenesis by promoting endothelial cells proliferation, survival, migration, invasion and by preventing of apoptosis. NRP2 acts as a co-receptor with VEGFR3 and the pro-lymphogenic factor VEGFC to facilitate tumour metastasis by promoting lymphangiogenesis. Although NRP1 and NRP2 do not have enzymatic signalling activity, the affinity of VEGFR2 for VEGFA-165 and VEGFR3 for VEGFC can increase in a co-receptor manner, as detailed in the schematic. The exclusive roles of NRP1 and NRP2 in signalling pathways are specifically described to emphasise the molecular regulatory mechanisms involved in co-receptors. Various studies have shown that the co-receptors NRP1 and NRP2 can be directly or indirectly targeted by different methods to prevent tumour angiogenesis and lymphangiogenesis. Therapeutic strategies targeting NRPs look promising soon as evidenced by preclinical and clinical studies.

The immunohistochemical landscape of the VEGF family and its receptors in glioblastomas

Background

Angiogenesis is one of the hallmarks of cancer. This complex mechanism of tumor progression provides tumors cells with essential nutrients. There have been a limited number of investigations of markers of angiogenesis in Glioblastomas (GBMs), and most previous studies have focused on VEGF-A. Recent evidence suggests that there is a complex lymphatic system in central nervous system (CNS), which suggests VEGF-C and VEGF–D as interesting biomarker candidates. This study was designed to evaluate the expressions of VEGF-A, −C, −D and their co-receptors, VEGFR-1, VEGFR-2, and VEGFR-3 by immunohistochemistry (IHC) using a series of GBMs. In addition, we evaluate any putative correlations between IHC expression levels of VEGF and clinical data of patients.

Methods

Tumor samples of 70 GBM patients (64 isocitrate dehydrogenase-1 wildtype (wtIDH-1) and 6 mutant (mutIDH-1)) were assessed by IHC using tissue microarray platforms for VEGF subunits and their co-receptors. The medical records were reviewed for clinical and therapeutic data.

Results

All VEGF subunits and receptors were highly expressed in GBMs: 57 out of 62 (91.9%), 53 out of 56 (94.6%) and 55 out of 63 cases (87.3%) showed VEGF-A, VEGF-C and -D imunoexpression, respectively. Interestingly, we had found both nuclear and cytoplasmic localization of VEGF-C staining in GBM tumor cells. The frequency of immunoexpression of VEGF receptors was the following: VEGFR-1, 65 out of 66 cases (98.5%); VEGFR-2, 63 out of 64 cases (98.4%); VEGFR-3, 49 out of 50 cases (90.0%). There were no significant differences in the patient overall survival (OS) related to the VEGF staining. A weak and monotonous correlation was observed between VEGF and its cognate receptors. The pattern of VEGF IHC was found to be similar when GBM mutIDH-1 subtypes were compared to wtIDH-1.

Conclusion

Both VEGF-C and –D, together with their receptors, were found to be overexpressed in the majority GBMs, and the IHC expression levels did not correlate with OS or IDH status. To understand the significance of the interactions and increased expression of VEGF-C, VEGF-D, VEGFR-2, and VEGFR-3 axis in GBM requires more extensive studies. Also, functional assays using a larger series of GBM is also necessary to better address the biological meaning of nuclear VEGF-C expression in tumor cells.

A review of predictive, prognostic and diagnostic biomarkers for brain tumours: towards personalised and targeted cancer therapy

Background:

Brain tumours are relatively rare disease but present a large medical challenge as there is currently no method for early detection of the tumour and are typically not diagnosed until patients have progressed to symptomatic stage which significantly decreases chances of survival and also minimises treatment efficacy. However, if brain cancers can be diagnosed at early stages and also if clinicians have the potential to prospectively identify patients likely to respond to specific treatments, then there is a very high potential to increase patients’ treatment efficacy and survival. In recent years, there have been several investigations to identify biomarkers for brain cancer risk assessment, early detection and diagnosis, the likelihood of identifying which group of patients will benefit from a particular treatment and monitoring patient response to treatment.

Materials and methods:

This paper reports on a review of 21 current clinical and emerging biomarkers used in risk assessment, screening for early detection and diagnosis, and monitoring the response of treatment of brain cancers.

Conclusion:

Understanding biomarkers, molecular mechanisms and signalling pathways can potentially lead to personalised and targeted treatment via therapeutic targeting of specific genetic aberrant pathways which play key roles in malignant brain tumour formation. The future holds promising for the use of biomarker analysis as a major factor for personalised and targeted brain cancer treatment, since biomarkers have the potential to measure early disease detection and diagnosis, the risk of disease development and progression, improved patient stratification for various treatment paradigms, provide accurate information of patient response to a specific treatment and inform clinicians about the likely outcome of a brain cancer diagnosis independent of the treatment received.

VEGF-C sustains VEGFR2 activation under bevacizumab therapy and promotes glioblastoma maintenance

Background

Glioblastoma ranks among the most lethal cancers, with current therapies offering only palliation. Paracrine vascular endothelial growth factor (VEGF) signaling has been targeted using anti-angiogenic agents, whereas autocrine VEGF/VEGF receptor 2 (VEGFR2) signaling is poorly understood. Bevacizumab resistance of VEGFR2-expressing glioblastoma cells prompted interrogation of autocrine VEGF-C/VEGFR2 signaling in glioblastoma.

Methods

Autocrine VEGF-C/VEGFR2 signaling was functionally investigated using RNA interference and exogenous ligands in patient-derived xenograft lines and primary glioblastoma cell cultures in vitro and in vivo. VEGF-C expression and interaction with VEGFR2 in a matched pre- and post-bevacizumab treatment cohort were analyzed by immunohistochemistry and proximity ligation assay.

Results

VEGF-C was expressed by patient-derived xenograft glioblastoma lines, primary cells, and matched surgical specimens before and after bevacizumab treatment. VEGF-C activated autocrine VEGFR2 signaling to promote cell survival, whereas targeting VEGF-C expression reprogrammed cellular transcription to attenuate survival and cell cycle progression. Supporting potential translational significance, targeting VEGF-C impaired tumor growth in vivo, with superiority to bevacizumab treatment.

Conclusions

Our results demonstrate VEGF-C serves as both a paracrine and an autocrine pro-survival cytokine in glioblastoma, promoting tumor cell survival and tumorigenesis. VEGF-C permits sustained VEGFR2 activation and tumor growth, where its inhibition appears superior to bevacizumab therapy in improving tumor control.

Neuropilins in the Context of Tumor Vasculature

Neuropilin-1 and Neuropilin-2 form a small family of plasma membrane spanning receptors originally identified by the binding of semaphorin and vascular endothelial growth factor. Having no cytosolic protein kinase domain, they function predominantly as co-receptors of other receptors for various ligands. As such, they critically modulate the signaling of various receptor tyrosine kinases, integrins, and other molecules involved in the regulation of physiological and pathological angiogenic processes. This review highlights the diverse neuropilin ligands and interacting partners on endothelial cells, which are relevant in the context of the tumor vasculature and the tumor microenvironment. In addition to tumor cells, the latter contains cancer-associated fibroblasts, immune cells, and endothelial cells. Based on the prevalent neuropilin-mediated interactions, the suitability of various neuropilin-targeted substances for influencing tumor angiogenesis as a possible building block of a tumor therapy is discussed.

Current Challenges and Opportunities in Treating Glioblastoma

Glioblastoma multiforme (GBM), the most common and aggressive primary brain tumor, has a high mortality rate despite extensive efforts to develop new treatments. GBM exhibits both intra- and intertumor heterogeneity, lending to resistance and eventual tumor recurrence. Large-scale genomic and proteomic analysis of GBM tumors has uncovered potential drug targets. Effective and “druggable” targets must be validated to embark on a robust medicinal chemistry campaign culminating in the discovery of clinical candidates. Here, we review recent developments in GBM drug discovery and delivery. To identify GBM drug targets, we performed extensive bioinformatics analysis using data from The Cancer Genome Atlas project. We discovered 20 genes, BOC, CLEC4GP1, ELOVL6, EREG, ESR2, FDCSP, FURIN, FUT8-AS1, GZMB, IRX3, LITAF, NDEL1, NKX3-1, PODNL1, PTPRN, QSOX1, SEMA4F, TH, VEGFC, and C20orf166AS1 that are overexpressed in a subpopulation of GBM patients and correlate with poor survival outcomes. Importantly, nine of these genes exhibit higher expression in GBM versus low-grade glioma and may be involved in disease progression. In this review, we discuss these proteins in the context of GBM disease progression. We also conducted computational multi-parameter optimization to assess the blood-brain barrier (BBB) permeability of small molecules in clinical trials for GBM treatment. Drug delivery in the context of GBM is particularly challenging because the BBB hinders small molecule transport. Therefore, we discuss novel drug delivery methods, including nanoparticles and prodrugs. Given the aggressive nature of GBM and the complexity of targeting the central nervous system, effective treatment options are a major unmet medical need. Identification and validation of biomarkers and drug targets associated with GBM disease progression present an exciting opportunity to improve treatment of this devastating disease.

Semaphorin 3C and Its Receptors in Cancer and Cancer Stem-Like Cells

Neurodevelopmental programs are frequently dysregulated in cancer. Semaphorins are a large family of guidance cues that direct neuronal network formation and are also implicated in cancer. Semaphorins have two kinds of receptors, neuropilins and plexins. Besides their role in development, semaphorin signaling may promote or suppress tumors depending on their context. Sema3C is a secreted semaphorin that plays an important role in the maintenance of cancer stem-like cells, promotes migration and invasion, and may facilitate angiogenesis. Therapeutic strategies that inhibit Sema3C signaling may improve cancer control. This review will summarize the current research on the Sema3C pathway and its potential as a therapeutic target.

NRP-2 in tumor lymphangiogenesis and lymphatic metastasis

Neuropilin-2 (NRP-2) not only functions as a receptor for semaphorins, a family of neural axon guidance factors, but also interacts with VEGFs, a family of vascular endothelial growth factors. As an independent receptor or a co-receptor, NRP-2 binds to ligands VEGF-C/D, activates the VEGF-C/D-NRP-2 signaling axis, and further regulates lymphangiogenesis-associated factors in both lymphatic endothelial cells (LECs) and some tumor cells during tumor progression. Via VEGF-C/D-NRP-2 axis, NRP-2 induces LEC proliferation, reconstruction and lymphangiogenesis and subsequently promotes tumor cell migration, invasion and lymphatic metastasis. There are similarities and differences among NRP-1, NRP-2 and VEGFR-3 in chemical structure, ligand specificity, chromosomal location, soluble protein forms, cellular functions and expression profiles. High expression of NRP-2 in LECs and tumor cells has been observed in different anatomic sites, histological patterns and progression stages of various tumors, especially during tumor lymphangiogenesis and lymphatic metastasis, and therefore the NRP-2 and VEGF-C/D-NRP-2 axis are closely related to tumor development, progression, invasion, and metastasis. In addition, it is important for prognosis of tumor. The studies on NRP-2 targeted therapy have recently achieved some successes, utilizing NRP-2 blocking antibodies, NRP-2 inhibitory peptides, soluble NRP-2 antagonists, small molecule inhibitors and various NRP-2 gene therapeutic strategies.

Overcoming blood–brain barrier by HER2-targeted nanosystem to suppress glioblastoma cell migration, invasion and tumor growth

Herein we synthesize an HER2 antibody-conjugated selenium nanoparticle platform can efficiently deliver both therapeutic agents and diagnostic agents (superparamagnetic iron oxide nanoparticles) across the BBB into the tumor tissues and enhances their effects on brain tumor treatment and MR imaging.

Prognostic value of preoperative von Willebrand factor plasma levels in patients with Glioblastoma

Circulating biomarker for malignant gliomas could improve both differential diagnosis and clinical management of brain tumor patients. Among all gliomas, glioblastoma (GBM) is considered the most hypervascularized tumor with activation of multiple proangiogenic signaling pathways that enhance tumor growth. To investigate whether preoperative antigen plasma level of von Willebrand Factor (VWF:Ag) might be possible marker for GBM onset, progression, and prognosis, we retrospectively examined 57 patients with histological diagnosis for GBM and 23 meningiomas (MNGs), benign intracranial expansive lesions, enrolled as controls. Blood samples were collected from all the patients before tumor resection. Plasma von Willebrand Factor (VWF):Ag levels were determined by using a latex particle‐enhanced immunoturbidimetric assay. The median levels of vWF:Ag were significantly higher in GBMs than in meningiomas (MNGs) (183 vs. 133 IU/dL, P = 0.01). The cumulative 1‐year survival was significantly shorter in patients with VWF:Ag levels >200 IU/dL than in those with levels <200 IU/dL and increased VWF levels were associated with a threefold higher risk of death in GBM patients. Our data suggest that VWF:Ag could be a circulating biomarker of disease malignancy, that could be considered, in association with other genetic and epigenetic factors, currently available in the GBM management. Future studies should investigate whether plasma VWF:Ag levels could also be used to monitor therapeutic effects and whether it may have a prognostic value.