Inhibition of epidermal growth factor receptor-associated tyrosine kinase blocks glioblastoma invasion of the brain

Triple therapy versus dual-antiplatelet therapy for dolichoectatic vertebrobasilar fusiform aneurysms treated with flow diverters

Background

Dolichoectatic vertebrobasilar fusiform aneurysms (DVBFAs) have poor natural history when left untreated and high morbimortality when treated with microsurgery. Flow diversion (FD) with dual-antiplatelet therapy (DAPT) is feasible but carries high risk of perforator occlusion and progression of brainstem compression. Elaborate antithrombotic strategies are needed to preserve perforator patency while vessel remodeling occurs. We compared triple therapy (TT (DAPT plus oral anticoagulation)) and DAPT alone in patients with DVBFAs treated with FD.

Methods

Retrospective comparison of DAPT and TT in patients with DVBFAs treated with FD at eight US centers.

Results

The groups (DAPT=13, TT=14) were similar in age, sex, clinical presentation, baseline disability, and aneurysm characteristics. Radial access use was significantly higher in the TT group (71.4% vs 15.3%; P=0.006). Median number of flow diverters and adjunctive coiling use were non-different between groups. Acute ischemic stroke rate during the oral anticoagulation period was lower in the TT group than the DAPT group (7.1% vs 30.8%; P=0.167). Modified Rankin Scale score decline was significantly lower in the TT group (7.1% vs 69.2%; P=0.001). Overall rates of hemorrhagic complications (TT, 28.6% vs DAPT, 7.7%; P=0.162) and complete occlusion (TT, 25% vs DAPT, 54.4%; P=0.213) were non-different between the groups. Rate of moderate-to-severe disability at last follow-up was significantly lower in the TT group (21.4% vs 76.9%; P=0.007).

Conclusions

Patients with DVBFAs treated with FD in the TT group had fewer ischemic strokes, less symptom progression, and overall better outcomes at last follow-up than similar patients in the DAPT group.

Flow Diversion of Posterior Circulation Aneurysms: Systematic Review of Disaggregated Individual Patient Data

BACKGROUND

Experience with endoluminal flow diversion for the treatment of posterior circulation aneurysms is limited.

PURPOSE

We sought to investigate factors associated with the safety and efficacy of this treatment by collecting disaggregated patient-level data from the literature.

DATA SOURCES

PubMed, EMBASE, and Ovid were searched up through 2019 for articles reporting flow diversion of posterior circulation aneurysms.

STUDY SELECTION

Eighty-four studies reported disaggregated data for 301 separate posterior circulation aneurysms.

DATA ANALYSIS

Patient, aneurysm, and treatment factors were collected for each patient. Outcomes included the occurrence of major complications, angiographic occlusion, and functional outcomes based on the mRS.

DATA SYNTHESIS

Significant differences in aneurysm and treatment characteristics were seen among different locations. Major complications occurred in 22%, angiographic occlusion was reported in 65% (11.3 months of mean follow-up), and good functional outcomes (mRS 0-2) were achieved in 67% (13.3 months of mean follow-up). Multivariate analysis identified age, number of flow diverters used, size, and prior treatment to be associated with outcome measures. Meta-analysis combining the current study with prior large nondisaggregated series of posterior circulation aneurysms treated with flow diversion found a pooled incidence of 20% (n = 712 patients) major complications and 75% (n = 581 patients) angiographic occlusions.

LIMITATIONS

This study design is susceptible to publication bias. Use of antiplatelet therapy was not uniformly reported.

CONCLUSIONS

Endoluminal flow diversion is an important tool in the treatment of posterior circulation aneurysms. Patient age, aneurysm size, prior treatment, and the number of flow diverters used are important factors associated with complications and outcomes.

The multifaceted NF-kB: are there still prospects of its inhibition for clinical intervention in pediatric central nervous system tumors?

Despite advances in the understanding of the molecular mechanisms underlying the basic biology and pathogenesis of pediatric central nervous system (CNS) malignancies, patients still have an extremely unfavorable prognosis. Over the years, a plethora of natural and synthetic compounds has emerged for the pharmacologic intervention of the NF-kB pathway, one of the most frequently dysregulated signaling cascades in human cancer with key roles in cell growth, survival, and therapy resistance. Here, we provide a review about the state-of-the-art concerning the dysregulation of this hub transcription factor in the most prevalent pediatric CNS tumors: glioma, medulloblastoma, and ependymoma. Moreover, we compile the available literature on the anti-proliferative effects of varied NF-kB inhibitors acting alone or in combination with other therapies in vitro, in vivo, and clinical trials. As the wealth of basic research data continues to accumulate, recognizing NF-kB as a therapeutic target may provide important insights to treat these diseases, hopefully contributing to increase cure rates and lower side effects related to therapy.

Combined standard bypass and parent artery occlusion for management of giant and complex internal carotid artery aneurysms

BACKGROUND

Complex aneurysms do not have a standard protocol for treatment. In this study, we investigate the safety and efficacy of microsurgical revascularization combined with parent artery occlusion (PAO) in giant and complex internal carotid artery (ICA) aneurysms.

METHODS

Between 1998 and 2017, 41 patients with 47 giant and complex ICA aneurysms were treated by an a priori planned combined treatment strategy. Clinical and radiological outcomes were stratified according to mRS and Raymond classification. Bypass patency was assessed. Median follow-up time was 3.9 years.

RESULTS

After successful STA-MCA bypass, staged endovascular (n=37) or surgical (n=1) PAO was executed in 38 patients following a negative balloon occlusion test. Intolerance to PAO led to stent/coil treatments in two patients. Perioperative bypass patency was confirmed in 100% of completed STA-MCA bypass procedures. Long-term overall bypass patency rate was 99%. Raymond 1 occlusion and good outcome were achieved in 95% and 97% (mRS 0-2) of cases, respectively. No procedure-related mortality was encountered. Eighty-four percent of patients with preoperative cranial nerve compression syndromes improved during follow-up.

CONCLUSIONS

The combined approach of STA-MCA bypass surgery followed by parent artery occlusion achieves high aneurysm occlusion and low morbidity rates in the management of giant and complex ICA aneurysms. This combined indirect approach represents a viable alternative to flow diversion in patients with cranial nerve compression syndromes or matricidal aneurysms, and may serve as a backup strategy in cases of peri-interventional complications or lack of suitable endovascular access.

Intracranial Metastases Originating From Pediatric Primary Spinal Cord Glioblastoma Multiforme: A Case Report and Literature Review

Primary spinal cord glioblastoma multiforme (scGBM) is an uncommon entity in pediatrics, and intracranial metastasis originating in spinal cord gliomas is very rare. A 7-year-old female presented with weakness in the limbs, paralysis of the lower limbs and incontinence. The initial MRI of the spinal cord revealed expansion and abnormal signals from T2 to T5. She was initially diagnosed with Neuromyelitis optica spectrum disorders and treated with high-dose glucocorticoid and gamma globulin. Four months later, her symptoms worsened and follow-up imaging showed multiple intracranial mass lesions. We performed a subtotal resection of the right thalamic basal ganglia tumor and gross total resection of the right frontal lobe tumor under microscopic examination. Histopathology revealed scGBM with intracranial metastasis and the molecular pathology diagnosis suggested H3K27M mutant diffuse midline glioma WHO grade IV, which had previously been misdiagnosed as a Neuromyelitis optica spectrum disorders. We review the literature of intracranial metastases originating from pediatric primary spinal cord glioblastoma multiforme and summarize possible methods of differentiation, including changes in muscle strength or tone, intramedullary heterogeneously enhancing solitary mass lesions and cord expansion in MRI. Finally, we emphasize that in unexpected radiological changes or disadvantageous response to the treatment, a biopsy to achieve a pathological diagnosis is necessary to discard other diseases, especially neoplasms.

The Fate of Unruptured Intracranial Vertebrobasilar Dissecting Aneurysm with Brain Stem Compression According to Different Treatment Modalities

BACKGROUND AND PURPOSE

Unruptured intracranial vertebrobasilar dissecting aneurysms with brain stem compression are difficult to treat. In the present study, the clinical and radiologic outcomes of unruptured intracranial vertebrobasilar dissecting aneurysms with brain stem compression based on different treatment modalities were evaluated.

MATERIALS AND METHODS

This study included 28 patients with unruptured intracranial vertebrobasilar dissecting aneurysms with brain stem compression treated from January 2009 to December 2017. Treatment methods were observation (n = 6), stent-assisted coil embolization (n = 9), parent artery occlusion (n = 6), and flow diversion (n = 7). The data of baseline characteristics, change of aneurysm size, retreatment rate, stroke occurrence, and alteration of the mRS score were obtained from retrospective chart review.

RESULTS

The initial size of dissecting aneurysms was largest in the flow diversion group (22.5 ± 7.7 mm), followed by parent artery occlusion (20.3 ± 8.4 mm), stent-assisted coil embolization (11.7 ± 2.2 mm), and observation (17.8 ± 5.5 mm; P = .01) groups. The reduction rate of aneurysm size was highest in the parent artery occlusion group (26.7 ± 32.1%), followed by flow diversion (14.1% ± 28.7%), stent-assisted coil embolization (-17.9 ± 30.3%), and observation (-31.5 ± 30.8%; P = .007) groups. Additional treatment was needed in the observation (4/6, 66.7%) and stent-assisted coil embolization (3/9, 33.3%; P = .017) groups. Improvement of the mRS score on follow-up was observed in the flow diversion (6/7, 85.7%) and parent artery occlusion (4/6, 66.7%) groups but not in the stent-assisted coil embolization and observation groups. A worsened mRS score was most common in the observation group (4/6, 66.7%), followed by stent-assisted coil embolization (3/9, 33.3%), parent artery occlusion (2/6, 33.3%), and flow diversion (0/7, 0%) groups.

CONCLUSIONS

When treating intracranial vertebrobasilar dissecting aneurysms with brain stem compression, parent artery occlusion and flow diversion should be considered to reduce aneurysm size and improve the mRS score.

CXCR2-Expressing Tumor Cells Drive Vascular Mimicry in Antiangiogenic Therapy-Resistant Glioblastoma

BACKGROUND: Glioblastoma (GBM) was shown to relapse faster and displayed therapeutic resistance to antiangiogenic therapies (AATs) through an alternative tumor cell-driven mechanism of neovascularization called vascular mimicry (VM). We identified highly upregulated interleukin 8 (IL-8)-CXCR2 axis in tumor cells in high-grade human glioma and AAT-treated orthotopic GBM tumors. METHODS: Human GBM tissue sections and tissue array were used to ascertain the clinical relevance of CXCR2-positive tumor cells in the formation of VM. We utilized U251 and U87 human tumor cells to understand VM in an orthotopic GBM model and AAT-mediated enhancement in VM was modeled using vatalanib (anti-VEGFR2) and avastin (anti-VEGF). Later, VM was inhibited by SB225002 (CXCR2 inhibitor) in a preclinical study. RESULTS: Overexpression of IL8 and CXCR2 in human datasets and histological analysis was identified as a bonafide candidate to validate VM through in vitro and animal model studies. AAT-treated tumors displayed a higher number of CXCR2-positive GBM-stem cells with endothelial-like phenotypes. Stable knockdown of CXCR2 expression in tumor cells led to decreased tumor growth as well as incomplete VM structures in the animal models. Similar data were obtained following SB225002 treatment. CONCLUSIONS: The present study suggests that tumor cell autonomous IL-8-CXCR2 pathway is instrumental in AAT-mediated resistance and VM formation in GBM. Therefore, CXCR2 can be targeted through SB225002 and can be combined with standard therapies to improve the therapeutic outcomes in clinical trials.

Cell cycle-dependent force transmission in cancer cells

The generation of traction forces and their transmission to the extracellular environment supports the disseminative migration of cells from a primary tumor. In cancer cells, the periodic variation of nuclear stiffness during the cell cycle provides a functional link between efficient translocation and proliferation. However, the mechanical framework completing this picture remains unexplored. Here, the Fucci2 reporter was expressed in various human epithelial cancer cells to resolve their cell cycle phase transition. The corresponding tractions were captured by a recently developed reference-free confocal traction-force microscopy platform. The combined approach was conducive to the analysis of phase-dependent force variation at the level of individual integrin contacts. Detected forces were invariably higher in the G1 and early S phases than in the ensuing late S/G2, and locally colocalized with high levels of paxillin phosphorylation. Perturbation of paxillin phosphorylation at focal adhesions, obtained through the biochemical inhibition of focal adhesion kinase (FAK) or the transfection of nonphosphorylatable or phosphomimetic paxillin mutants, significantly diminished the force transmitted to the substrate. These data demonstrate a reproducible modulation of force transmission during the cell cycle progression of cancer cells, instrumental to their invasion of dense environments. In addition, they delineate a model in which paxillin phosphorylation supports the mechanical maturation of adhesions relaying forces to the substrate.

Connexin 43 C-terminus directly inhibits the hyperphosphorylation of Akt/ERK through protein-protein interactions in glioblastoma

Although the deregulation of epidermal growth factor receptor (EGFR) is one of the most common molecular mechanisms of glioblastoma (GBM) pathogenesis, the efficacy of anti-EGFR therapy is limited. Additionally, response to anti-EGFR therapy is not solely dependent on EGFR expression and is more promising in patients with reduced activity of EGFR downstream signaling pathways. Thus, there is considerable interest in identifying the compensatory regulatory factors of the EGFR signaling pathway to improve the efficacy of anti-EGFR therapies for GBM. In this study, we confirmed the low efficacy of EGFR inhibitors in GBM patients by meta-analysis. We then identified a negative correlation between connexin 43 (Cx43) expression and Akt/ERK activation, which was caused by the direct interactions between Akt/ERK and Cx43. By comparing the interactions between Akt/ERK and Cx43 using a series of truncated and mutated Cx43 variants, we revealed that the residues T286/A305/Q308/Y313 and S272/S273 at the carboxy terminus of Cx43 are critical for its binding with Akt and ERK, respectively. In addition, Kaplan-Meier survival analysis using data from The Cancer Genome Atlas datasets indicated that the expression of Cx43 significantly improved the prognosis of GBM patients who express EGFR. Together, our results suggested that Cx43 acts as an inhibitory regulator of the activation of growth factor receptor downstream signaling pathways, indicating the potential of Cx43 as a marker for predicting the efficacy of EGFR inhibitor treatments for GBM. Targeting the interaction between the carboxy terminus of Cx43 and Akt/ERK could be an effective therapeutic strategy against GBM.

Hemodynamic Changes Caused by Multiple Stenting in Vertebral Artery Fusiform Aneurysms: A Patient-Specific Computational Fluid Dynamics Study

BACKGROUND AND PURPOSE

The multiple stent placement technique has largely improved the long-term outcomes of intracranial fusiform aneurysms, but the hemodynamic mechanisms remain unclear. In this study, we analyzed the hemodynamic changes caused by different stent-placement strategies in patient-specific models using the computational fluid dynamics technique, aiming to provide evidence for clinical decision-making.

MATERIALS AND METHODS

Ten vertebral artery fusiform aneurysms were included, and their patient-specific computational fluid dynamics models were reconstructed. A fast virtual stent placement technique was used to simulate sequential multiple stent placements (from a single stent to triple stents) in the vertebral artery fusiform aneurysm models. Hemodynamic parameters, including wall shear stress, pressure, oscillatory shear index, relative residence time, and flow pattern, were calculated and compared among groups with different numbers of stents.

RESULTS

Virtual stents were deployed in all 10 cases successfully, consistent with the real stent configuration. Wall shear stress decreased progressively by 7.2%, 20.6%, and 25.8% as the number of stents increased. Meanwhile, relative residence time and pressure increased on average by 11.3%, 15.4%, and 45.0% and by 15.7%, 21.5%, and 28.2%. The oscillatory shear index showed no stable variation trend. Flow patterns improved by weakening the intensity of the vortices and displacing the vortex center from the aneurysmal wall.

CONCLUSIONS

Stent placement modifies hemodynamic patterns in vertebral artery fusiform aneurysms, which might favor thrombosis formation in the aneurysmal sac. This effect is amplified with the number of stents deployed. However, a potential risk of rupture or recanalization exists and should be considered when planning to use the multiple stent placement technique in vertebral artery fusiform aneurysms.

Meta-analysis of treatment outcomes of posterior circulation non-saccular aneurysms by flow diverters

INTRODUCTION

Non-saccular aneurysms of the posterior circulation are uncommon but highly dangerous lesions. Flow diverter stents have been demonstrated to be effective treatments of various anterior circulation aneurysms, particularly large and giant proximal internal carotid artery aneurysms. However, evidence regarding the treatment of non-saccular posterior circulation aneurysms with flow diverters is lacking.

METHODS

A systematic literature review of the English language literature since 2007 was conducted using PubMed, MEDLINE, and Embase. Keywords and MeSH terms included flow diversion, flow diverter, pipeline, surpass, intracranial aneurysm, vertebrobasilar, and non-saccular. Case reports were excluded. Angiographic and clinical outcomes were pooled using a random effects meta-analysis.

RESULTS

13 retrospective non-comparative studies reporting 129 patients and 131 aneurysm treatments were included. The average number of flow diverters per aneurysm was 4.33. Immediate complete or near complete occlusion of the aneurysm occurred in 25% (95% CI 1% to 60%), and long term occlusion in 52% (29-76%). Periprocedural stroke occurred in 23% of cases. Good long term neurologic outcome (modified Rankin Scale score ≤2) was achieved in 51% (95% CI 31% to 71%). Overall mortality was 21% (95% CI 7% to 38%) and morbidity was 26% (12%-42%). Retreatment was required in 5% (95% CI 0% to 14%). Good neurologic outcome rate was higher in vertebral artery aneurysms (83%) than other locations (18-33%).

CONCLUSIONS

Flow diversion is a feasible and efficacious treatment for non-saccular aneurysms in the posterior circulation. However, the intervention carries a significant risk of periprocedural stroke, and is still associated with high overall mortality. Further studies are needed to identify significant treatment risk factors and optimize patient selection.

EGFR and EGFRvIII Promote Angiogenesis and Cell Invasion in Glioblastoma: Combination Therapies for an Effective Treatment

Epidermal growth factor receptor (EGFR) and the mutant EGFRvIII are major focal points in current concepts of targeted cancer therapy for glioblastoma multiforme (GBM), the most malignant primary brain tumor. The receptors participate in the key processes of tumor cell invasion and tumor-related angiogenesis and their upregulation correlates with the poor prognosis of glioma patients. Glioma cell invasion and increased angiogenesis share mechanisms of the degradation of the extracellular matrix (ECM) through upregulation of ECM-degrading proteases as well as the activation of aberrant signaling pathways. This review describes the role of EGFR and EGFRvIII in those mechanisms which might offer new combined therapeutic approaches targeting EGFR or EGFRvIII together with drug treatments against proteases of the ECM or downstream signaling to increase the inhibitory effects of mono-therapies.

Clinical and Imaging Characteristics of Diffuse Intracranial Dolichoectasia

BACKGROUND AND PURPOSE

Among patients with vertebrobasilar dolichoectasia is a subset of patients with disease affecting the anterior circulation as well. We hypothesized that multivessel intracranial dolichoectasia may represent a distinct phenotype from single-territory vertebrobasilar dolichoectasia. The purpose of this study was to characterize clinical characteristics and angiographic features of this proposed distinct phenotype termed "diffuse intracranial dolichoectasia" and compare them with those in patients with isolated vertebrobasilar dolichoectasia.

MATERIALS AND METHODS

We retrospectively reviewed a consecutive series of patients with diffuse intracranial dolichoectasia and compared their demographics, vascular risk factors, additional aneurysm prevalence, and clinical outcomes with a group of patients with vertebrobasilar dolichoectasia. "Diffuse intracranial dolichoectasia" was defined as aneurysmal dilation of entire vascular segments involving ≥2 intracranial vascular beds. Categoric and continuous variables were compared by using χ² and Student t tests, respectively.

RESULTS

Twenty-five patients had diffuse intracranial dolichoectasia, and 139 had vertebrobasilar dolichoectasia. Patients with diffuse intracranial dolichoectasia were older than those with vertebrobasilar dolichoectasia (70.9 ± 14.2 years versus 60.4 ± 12.5 years, P = .0002) and had a higher prevalence of abdominal aortic aneurysms (62.5% versus 14.3%, P = .01), other visceral aneurysms (25.0% versus 0%, P < .0001), and smoking (68.0% versus 15.9%, P < .0001). Patients with diffuse intracranial dolichoectasia were more likely to have aneurysm growth (46.2% versus 21.5%, P = .09) and rupture (20% versus 3.5%, P = .007) at follow-up. Patients with diffuse intracranial dolichoectasia were less likely to have good neurologic function at follow-up (24.0% versus 57.6%, P = .004) and were more likely to have aneurysm-related death (24.0% versus 7.2%, P = .02).

CONCLUSIONS

The natural history of patients with diffuse intracranial dolichoectasia is significantly worse than that in those with isolated vertebrobasilar dolichoectasia. Many patients with diffuse intracranial dolichoectasia had additional saccular and abdominal aortic aneurysms. These findings suggest that diffuse intracranial dolichoectasia may be a distinct vascular phenotype secondary to a systemic arteriopathy affecting multiple vascular beds.

Brain Tumor Genetic Modification Yields Increased Resistance to Paclitaxel in Physical Confinement

Brain tumor cells remain highly resistant to radiation and chemotherapy, particularly malignant and secondary cancers. In this study, we utilized microchannel devices to examine the effect of a confined environment on the viability and drug resistance of the following brain cancer cell lines: primary cancers (glioblastoma multiforme and neuroblastoma), human brain cancer cell lines (D54 and D54-EGFRvIII), and genetically modified mouse astrocytes (wild type, p53-/-, p53-/- PTEN-/-, p53-/- Braf, and p53-/- PTEN-/- Braf). We found that loss of PTEN combined with Braf activation resulted in higher viability in narrow microchannels. In addition, Braf conferred increased resistance to the microtubule-stabilizing drug Taxol in narrow confinement. Similarly, survival of D54-EGFRvIII cells was unaffected following treatment with Taxol, whereas the viability of D54 cells was reduced by 75% under these conditions. Taken together, our data suggests key targets for anticancer drugs based on cellular genotypes and their specific survival phenotypes during confined migration.

Evolution of Flow-Diverter Endothelialization and Thrombus Organization in Giant Fusiform Aneurysms after Flow Diversion: A Histopathologic Study

BACKGROUND AND PURPOSE

Treatment of giant fusiform aneurysms with flow diverters has been associated with a relatively high rate of complications. Our goal was to study the evolution of flow-diverter endothelialization and thrombus organization at different time points after flow-diverter treatment in giant fusiform aneurysms to better understand reasons for flow-diverter thrombosis and delayed aneurysm ruptures.

MATERIALS AND METHODS

Two giant anterior and 2 posterior circulation aneurysms, all of which had partially thrombosed before treatment, were studied. An unruptured, untreated posterior circulation aneurysm was used as a control. Each specimen was removed at 7 days or at 6, 9, or 13 months after flow-diverter treatment. The 3 patients who survived longer than 7 days were followed up by angiography and MR imaging. Formaldehyde-fixed paraffin-embedded sections were stained by using H&E, Van Gieson elastic, CD34, h-Caldesmon, and Picrosirius stains and studied by light microscopy.

RESULTS

According to angiography, aneurysms were found to be obliterated partially at 6 and 9 months and completely at 13 months. MR imaging revealed that mass effect remained unchanged in each case. Sections of the flow diverter within the normal parent artery were covered by an endothelialized fibrous layer as early as 6 months, but there was no tissue coverage or endothelialization seen even at 13 months inside the aneurysm itself. Each treated aneurysm had a thin wall with complete lack of smooth muscle cells. No signs of thrombus organization were found at any of the time points studied.

CONCLUSIONS

Endothelialization of the flow diverter in giant fusiform aneurysms may not occur and thrombus organization may not be initiated inside these aneurysms for as long as 1 year, which explains delayed flow-diverter thrombosis and the possibility of delayed ruptures.

Ranking adverse drug reactions with crowdsourcing

BACKGROUND

There is no publicly available resource that provides the relative severity of adverse drug reactions (ADRs). Such a resource would be useful for several applications, including assessment of the risks and benefits of drugs and improvement of patient-centered care. It could also be used to triage predictions of drug adverse events.

OBJECTIVE

The intent of the study was to rank ADRs according to severity.

METHODS

We used Internet-based crowdsourcing to rank ADRs according to severity. We assigned 126,512 pairwise comparisons of ADRs to 2589 Amazon Mechanical Turk workers and used these comparisons to rank order 2929 ADRs.

RESULTS

There is good correlation (rho=.53) between the mortality rates associated with ADRs and their rank. Our ranking highlights severe drug-ADR predictions, such as cardiovascular ADRs for raloxifene and celecoxib. It also triages genes associated with severe ADRs such as epidermal growth-factor receptor (EGFR), associated with glioblastoma multiforme, and SCN1A, associated with epilepsy.

CONCLUSIONS

ADR ranking lays a first stepping stone in personalized drug risk assessment. Ranking of ADRs using crowdsourcing may have useful clinical and financial implications, and should be further investigated in the context of health care decision making.

Endoluminal Reconstruction for Nonsaccular Aneurysms of the Proximal Posterior Cerebral Artery with the Pipeline Embolization Device

BACKGROUND AND PURPOSE

Treatment options for nonsaccular posterior cerebral artery aneurysms include a range of surgical and endovascular reconstructive and deconstructive methods. However, no truly satisfactory treatment option is available to date for lesions arising from the P1 and P2 segments. The purpose of the present case series is to investigate both the efficacy and safety of the Pipeline Embolization Device in treating these challenging aneurysms.

MATERIALS AND METHODS

We present a series of 6 consecutive patients who underwent endoluminal reconstruction with the Pipeline Embolization Device for nonsaccular P1 or P2 segment aneurysms between January 2009 and June 2013.

RESULTS

Aneurysm location included the P1 segment in 2 patients and the P2 segment in 4 patients. Mean aneurysm diameter was 23 mm (range, 5-44 mm). Mean length of the arterial segment involved was 10 mm (range, 6-19 mm). Clinical presentation included mass effect in 4 patients and perforator stroke and subacute aneurysmal subarachnoid hemorrhage in 1 patient each. Endovascular reconstruction was performed by using 1 Pipeline Embolization Device in 5 patients and 2 overlapping Pipeline Embolization Devices in the remaining patient. Angiographic aneurysm occlusion was immediate in 1 patient, within 6 months in 4 patients, and within 1 year in the remaining patient. Index symptoms resolved in 4 patients and stabilized in the remaining 2. No new permanent neurologic sequelae and no aneurysm recurrence were recorded during the mean follow-up period of 613 days (range, 540-725 days).

CONCLUSIONS

Endovascular reconstruction with the Pipeline Embolization Device for nonsaccular aneurysms arising from the P1 and P2 segments compares favorably with historical treatment options in terms of occlusion rate, margin of safety, and neurologic outcome.

Use of flow-diverting devices in fusiform vertebrobasilar giant aneurysms: a report on periprocedural course and long-term follow-up

BACKGROUND AND PURPOSE

Fusiform vertebrobasilar giant aneurysms are a rare (<1% of all intracranial aneurysms) but challenging aneurysm subtype. Little data are available on the natural history of this aneurysm subtype and the impact of the use of flow-diverting stents on the long-term clinical and imaging follow-up. In this article, we present our experience with the treatment of fusiform vertebrobasilar giant aneurysms by flow diverting stents. We aim to stimulate a discussion of the best management paradigm for this challenging aneurysm subtype.

MATERIALS AND METHODS

We retrospectively identified 6 patients with fusiform vertebrobasilar giant aneurysms who had been treated with flow-diverting stents between October 2009 and March 2012 in our center. The available data were re-evaluated. The modified Rankin Scale score was assessed before intervention, during the stay in hospital, and at discharge.

RESULTS

Six patients were identified (all male; age range, 49-71 years; median age, 60 years). Handling of material was successful in all cases. No primary periprocedural complications occurred. The mean follow-up was 13 months (15 days to 29 months). During follow-up, 3 of 6 patients had recurrent cerebral infarctions, but no patient experienced SAH. Two patients presented with acute thrombotic stent occlusion. The modified Rankin Scale score was not higher than 3 in any of the cases before intervention, whereas the best mRS score at the last follow-up was 5. Four of 6 patients died during follow-up.

CONCLUSIONS

Endovascular treatment of fusiform vertebrobasilar giant aneurysms with flow-diverting devices is feasible from a technical point of view; however, changes in hemodynamics with secondary thrombosis are not predictable. We currently do not intend to treat fusiform vertebrobasilar giant aneurysms with flow-diverting devices until we have further understanding of the pathophysiology, natural history, and hemodynamic effects of flow diversion.

Cells with intense EGFR staining and a high nuclear to cytoplasmic ratio are specific for infiltrative glioma: a useful marker in neuropathological practice

BACKGROUND

The differential diagnosis between infiltrative glioma (IG) and benign or curable glial lesions, such as gliosis, pilocytic astrocytoma, dysembryoplastic neuroepithelial tumor, ganglioglioma, or demyelinating disease, may be challenging for the pathologist because specific markers are lacking. Recently, we described a strong EGFR immunolabelling pattern in cells with a high nuclear to cytoplasmic ratio that enables the discrimination of low-grade IG from gliosis. The aim of this study was to extend our observation to high-grade glioma to assess whether EGFR expression pattern is of value in the discrimination of all IG from noninfiltrative glial lesions (NIG), including gliosis, benign tumors, and demyelinating disease.

METHODS

One hundred one IG and 58 NIG were compared for immunohistochemical expression of EGFR with use of an antibody that recognizes an epitope in the extracellular domain of both EGFRwt and EGFRvIII. Highly EGFR-positive cells with a high nuclear to cytoplasmic ratio were isolated and further characterized.

RESULTS

Cells with intense EGFR staining and a high nuclear to cytoplasmic ratio were significantly associated with the diagnosis of IG (P < .0001). The sensitivity and specificity of this staining pattern for the diagnosis of IG were 95% and 100%, respectively. EGFR expression was independent of IDH1 mutations and EGFR amplification. Finally, we showed that these particular cells displayed the phenotype and properties of glial progenitors and coexpressed CXCR4, a marker of invasiveness.

CONCLUSIONS

We demonstrate that cells with intense EGFR staining and a high nuclear to cytoplasmic ratio are specific criteria for the diagnosis of IG, irrespective of grade, histological subtype, and progression pathway, and their identification represents a tool to discriminate IG from benign or curable glial lesions.

Reconstructive endovascular treatment of fusiform and dissecting basilar trunk aneurysms with flow diverters, stents, and coils

BACKGROUND AND PURPOSE

Patients with fusiform basilar trunk aneurysms have a poor prognosis. Reconstructive endovascular therapy is possible with modern devices. We describe the clinical presentation, radiologic features, and clinical outcome of 13 patients with fusiform basilar trunk aneurysms treated with flow diverters, stents, and coils.

MATERIALS AND METHODS

Of the 13 patients, 7 were men and 6 were women with a mean age of 59.7 years. Clinical presentation was SAH in 3 patients, mass effect on the brain stem in 4 patients, vertebral artery dissection in 1 patient, and the aneurysm was an incidental finding in 5 patients. Mean aneurysm size was 21 mm. All except 1 were large or giant aneurysms. Nine aneurysms were partially thrombosed.

RESULTS

Stents were used in all 13 patients, in 2 patients with additional flow diverters and in 11 patients with additional coils. In 4 patients, 1 vertebral artery was subsequently occluded with coils to decrease flow into the aneurysm. Of 13 patients, 9 had a good outcome with adequate aneurysm occlusion and stable size on follow-up of 6-72 months. One of 3 patients who presented with SAH died of a rebleed 1 month later. One other patient died soon after treatment of in-stent thrombosis, and another patient became mute after treatment. In 2 of 3 patients who presented with symptoms of mass effect, there was improvement at a follow-up of 6-24 months.

CONCLUSIONS

Reconstructive endovascular therapy of fusiform and dissecting basilar trunk aneurysms is feasible but carries substantial risks. The safety and effectiveness in relation to natural history has not yet been elucidated.

Intracranial metastasis of spinal intramedullary anaplastic astrocytoma

Meningeal spread of spinal intramedullary astrocytoma into the cranium is rare. Only few case reports are available so far in the literature. We report a case of intramedullary high grade astrocytoma of the conus, developing intracranial metastasis after three months of partial excision of the spinal mass. The need for radical surgery, entire neuroaxis radiation, and adjuvant chemotherapy is suggested in the management of malignant spinal cord astrocytoma to prevent dissemination.

MR imaging of partially thrombosed cerebral aneurysms: characteristics and evolution

BACKGROUND AND PURPOSE

A comprehensive evaluation of aneurysmal morphometry requires appreciation of both the vascular lumen and the intraluminal thrombus. MR imaging methods can both evaluate the lumen and directly image the vessel wall. We investigated the ability of T1-weighted, T2-weighted, and steady-state MR imaging techniques to delineate thrombus morphology and reveal changes with time.

MATERIALS AND METHODS

Nine patients with fusiform basilar or intracranial vertebral artery aneurysms that contained intraluminal thrombus were studied with MR imaging. All patients underwent at least 2 imaging sessions, which were separated by 4-22 months. Analysis of signal intensity to determine the mean signal intensity from thrombus, blood, CSF, and brain in matched regions was performed. Aneurysm maximal diameter and cross-sectional area were determined with and without thrombus.

RESULTS

Thrombus was identified on all image sequences, and its general appearance was consistent between imaging sessions. Thrombus produced the highest and most consistent signal intensities with T1-weighted and steady-state techniques, though the latter showed superior contrast between luminal blood and thrombus. Heterogeneity within clot was evident in 4/9 of patients, with peripheral hyperintensity being a common feature.

CONCLUSIONS

Steady-state imaging was found to be superior to T1- and T2-weighted imaging for delineating and characterizing intraluminal thrombus within aneurysms. The imaging characteristics of intraluminal thrombus proved to be very consistent for long periods. Assessment of overall aneurysm size, including thrombosed portions, permits more accurate evaluation of aneurysm growth and concomitantly may permit more informed clinical decision-making with regard to the timing and need for aneurysm treatment.

Effect of combination treatment of rapamycin and isoflavones on mTOR pathway in human glioblastoma (U87) cells

Glioblastoma Multiforme (GBM) is a malignant primary brain tumor associated with poor survival rate. PI3K/Akt pathway is highly upregulated in gliomas due to deletion or mutation of PTEN and its activation is associated with tumor grade. mTOR is downstream from PI3K/Akt pathway and it initiates translation through its action on S6K and 4E-BP1. mTOR is an important therapeutic target in many cancers, including glioblastomas. Rapamycin and its analogues are known to inhibit mTOR pathway; however, they also show simultaneous upregulation of Akt and eIF4E survival pathways on inhibition of mTOR, rendering cells more resistant to rapamycin treatment. In this study we investigated the effect of combination treatment of rapamycin with isoflavones such as genistein and biochanin A on mTOR pathway and activation of Akt and eIF4E in human glioblastoma (U87) cells. Our results show that combination treatment of rapamycin with isoflavones, especially biochanin A at 50 muM, decreased the phosphorylation of Akt and eIF4E proteins and rendered U87 cells more sensitive to rapamycin treatment when compared to cells treated with rapamycin alone. These results suggest the importance of combining chemopreventive with chemotherapeutic agents in order to increase the efficacy of chemotherapeutic drugs.

Genistein reduces glycosaminoglycan levels in a mouse model of mucopolysaccharidosis type II

BACKGROUND AND PURPOSE

Mucopolysaccharidoses (MPS) are lysosomal storage disorders resulting from a deficit of specific lysosomal enzymes catalysing glycosaminoglycan (GAG) degradation. The typical pathology involves most of the organ systems, including the brain, in its severe forms. The soy isoflavone genistein has recently attracted considerable attention as it can reduce GAG synthesis in vitro. Furthermore, genistein is able to cross the blood-brain barrier in the rat. The present study was undertaken to assess the ability of genistein to reduce urinary and tissue GAG levels in vivo.

EXPERIMENTAL APPROACH

We used mice with genetic deletion of iduronate-2-sulphatase (one of the GAG catabolizing enzymes) which provide a model of MPS type II. Two doses of genistein, 5 or 25 mg.kg(-1).day(-1), were given, in the diet for 10 or 20 weeks. Urinary and tissue GAG content was evaluated by biochemical and histochemical procedures.

KEY RESULTS

Urinary GAG levels were reduced after 10 weeks' treatment with genistein at either 5 or 25 mg.kg(-1).day(-1). In tissue samples from liver, spleen, kidney and heart, a reduction in GAG content was observed with both dosages, after 10 weeks' treatment. Decreased GAG deposits in brain were observed after genistein treatment in some animals.

CONCLUSIONS AND IMPLICATIONS

There was decreased GAG storage in the MPSII mouse model following genistein administration. Our results would support the use of this plant-derived isoflavone in a combined therapeutic protocol for treatment of MPS.

A phase II trial of erlotinib in patients with recurrent malignant gliomas and nonprogressive glioblastoma multiforme postradiation therapy

Patients with (a) recurrent malignant glioma (MG): glioblastoma (GBM) or recurrent anaplastic glioma (AG), and (b) nonprogressive (NP) GBM following radiation therapy (RT) were eligible. Primary objective for recurrent MG was progression-free survival at 6 months (PFS-6) and overall survival at 12 months for NP GBM post-RT. Secondary objectives for recurrent MGs were response, survival, assessment of toxicity, and pharmacokinetics (PKs). Treatment with enzyme-inducing antiepileptic drugs was not allowed. Patients received 150 mg/day erlotinib. Patients requiring surgery were treated 7 days prior to tumor removal for PK analysis and effects of erlotinib on epidermal growth factor receptor (EGFR) and intracellular signaling pathways. Ninety-six patients were evaluable (53 recurrent MG and 43 NP GBM); 5 patients were not evaluable for response. PFS-6 in recurrent GBM was 3% with a median PFS of 2 months; PFS-6 in recurrent AG was 27% with a median PFS of 2 months. Twelve-month survival was 57% in NP GBMs post-RT. Primary toxicity was dermatologic. The tissue-to-plasma ratio normalized to nanograms per gram dry weight for erlotinib and OSI-420 ranged from 25% to 44% and 30% to 59%, respectively, for pretreated surgical patients. No effect on EGFR or intratumoral signaling was seen. Patients with NP GBM post-RT who developed rash in cycle 1 had improved survival (P < .001). Single-agent activity of erlotinib is minimal for recurrent MGs and marginally beneficial following RT for NP GBM patients. Development of rash in cycle 1 correlates with survival in patients with NP GBM after RT.

Reconstructive endovascular treatment of intracranial fusiform aneurysms: a 1-stage procedure with stent and balloon

BACKGROUND AND PURPOSE

Intracranial fusiform aneurysms, which incorporate the branch vessel and require salvaging of the parent vessel, are difficult to manage. The goal of this study was to evaluate the efficacy of reconstructive endovascular treatment of intracranial fusiform aneurysms by using a 1-stage procedure with a stent and balloon.

MATERIALS AND METHODS

During a 3-year period, 20 patients with 20 intracranial fusiform aneurysms were treated by using a 1-stage procedure involving a balloon and stent. Subarachnoid hemorrhage was present in 15 patients. Five aneurysms were located in the anterior circulation and 15, in the posterior circulation. Clinical outcomes and periprocedural complications were evaluated in all patients. The extent of coil packing was evaluated by control angiography after embolization and classified as either complete occlusion or partial occlusion. Angiography was performed 6, 12, and 24 months after embolization to evaluate stent patency and coil packing.

RESULTS

The 1-stage procedure by using a combination of balloon and stent was technically successful in all patients. There were no complications related to the procedure, complete occlusion was obtained in 16 patients, and partial occlusion, in 4 patients. All patients recovered well except for 2 who died due to causes unrelated to the procedure. Clinical follow-up was performed in all surviving patients at a mean of 12.3 months (range, 7-24 months), and angiography showed that the patent parent arteries were free of aneurysm recanalization or in-stent stenosis.

CONCLUSIONS

This 1-stage procedure may provide a feasible and safe treatment strategy for the management of intracranial fusiform aneurysms that are not amenable to deconstructive embolization.

Fyn and SRC are effectors of oncogenic epidermal growth factor receptor signaling in glioblastoma patients

Activating epidermal growth factor receptor (EGFR) mutations are common in many cancers including glioblastoma. However, clinical responses to EGFR inhibitors are infrequent and short-lived. We show that the Src family kinases (SFK) Fyn and Src are effectors of oncogenic EGFR signaling, enhancing invasion and tumor cell survival in vivo. Expression of a constitutively active EGFR mutant, EGFRvIII, resulted in activating phosphorylation and physical association with Src and Fyn, promoting tumor growth and motility. Gene silencing of Fyn and Src limited EGFR- and EGFRvIII-dependent tumor cell motility. The SFK inhibitor dasatinib inhibited invasion, promoted tumor regression, and induced apoptosis in vivo, significantly prolonging survival of an orthotopic glioblastoma model expressing endogenous EGFRvIII. Dasatinib enhanced the efficacy of an anti-EGFR monoclonal antibody (mAb 806) in vivo, further limiting tumor growth and extending survival. Examination of a large cohort of clinical samples showed frequent coactivation of EGFR and SFKs in glioblastoma patients. These results establish a mechanism linking EGFR signaling with Fyn and Src activation to promote tumor progression and invasion in vivo and provide rationale for combined anti-EGFR and anti-SFK targeted therapies.

Intracranial Metastases of Cervical Intramedullary Low-Grade Astrocytoma without Malignant Transformation in Adult

The first case of intracranial metastases of a cervical intramedullary low-grade astrocytoma without malignant transformation in adult is presented in this report. Seven years ago, a 45 year-old male patient underwent biopsy to confirm pathologic characteristics and received craniocervical radiation and chemotherapy for a grade II astrocytoma in the cervical spinal cord. Two years later, posterior fusion was necessary for progressive kyphosis in the cervical spine. He was well for approximately 7 years after the primary surgery. Two months ago, he presented with partial weakness and incoordination with gait difficulty. MRI Scan demonstrated multiple small lesions in the cerebellar vermis and left hemisphere. After suboccipital craniectomy and posterior cervical exposure, the small masses in the cerebellar vermis and hemispheres were excised to a large extent by guidance of an intraoperative navigation system. The tumor at the cervical and brain lesions was classified as an astrocytoma (WHO grade II). When a patient with low-grade astrocytoma in the spinal cord has new cranial symptoms after surgery, radiaton, and chemotherapy, the possibility of its metastasis should be suspected because it can spread to the intracranial cavity even without malignant transformation as shown in this case.

Radiosensitisation of U87MG brain tumours by anti-epidermal growth factor receptor monoclonal antibodies

As epidermal growth factor receptor (EGFR) has been reported to be a radiation response modulator, HER inhibitors are regarded to act as potential radiosensitisers. Our study examined the role of nimotuzumab and cetuximab both, the two monoclonal antibodies (mAbs) to EGFR, as radiosensitisers in a murine glioma model in vivo. Co-administration of both the antibodies with radiation increased the radiosensitivity of U87MG, resulting in a significant delay of subcutaneous (s.c.) tumour growth. Furthermore, the addition of antibodies to the radiation decreased brain tumour sizes and is inhibited by 40–80% the increased tumour cell invasion provoked by radiotherapy, although promoted tumour cell apoptosis. Whereas nimotuzumab led to a reduction in the size of tumour blood vessels and proliferating cells in s.c. tumours, cetuximab had no significant antiangiogenic nor antiproliferative activity. In contrast, cetuximab induced a more marked inhibition of EGFR downstream signalling compared with nimotuzumab. Moreover, both antibodies reduced the total number of radioresistant CD133+ cancer stem cells (CSCs). These results were encouraging, and showed the superiority of combined treatment of mAbs to EGFR and radiation over each single therapy against glioblastoma multiforme (GBM), confirming the role of these drugs as radiosensitisers in human GBM. In addition, we first showed the ability of mAb specifics against EGFR to target radioresistant glioma CSC, supporting the potential use in patients.

Spinal cord pilocytic astrocytoma with leptomeningeal dissemination to the brain. Case report and review of the literature

Leptomeningeal dissemination of low-grade spinal cord gliomas is an uncommon event. The authors report a unique case of leptomeningeal dissemination of a spinal cord pilocytic astrocytoma (PCA) to the intracranial cerebral subarachnoid spaces in a child. A 2-year-old boy presented with a loss of balance and the inability to walk or stand. An intradural intramedullary spinal cord tumor was identified, and the lesion was subtotally resected and diagnosed by the pathology department to be a PCA. Subsequently, the patient had recurrences of the intradural intramedullary tumor at 6 months and 2 years after his original presentation. He underwent a repeated resection of the recurrent tumor and fenestration of an associated syrinx on both occasions. The pathological characteristics of the reresected tumor remained consistent with those of a PCA. Postoperative imaging after his last surgery revealed diffuse intracranial leptomeningeal dissemination into the cisternal space surrounding the midbrain, the suprasellar region, and the internal auditory canal, as well as nodular subarachnoid disease in the upper cervical region. The patient then underwent chemotherapy, and total spine magnetic resonance (MR) imaging 2 months later demonstrated stability in the size of the spinal cord tumor and a decrease in the associated syrinx. However, an MR image of the head demonstrated two new areas of supratentorial subarachnoid leptomeningeal spread of the primary spinal cord tumor at the 2-month follow-up examination. At the 6-month follow-up examination, MR imaging of the head and spine demonstrated stable metastatic disease. This case illustrates a unique instance of supratentorial leptomeningeal dissemination of an intramedullary spinal cord PCA in a child.

A mathematical model of glioblastoma tumor spheroid invasion in a three-dimensional in vitro experiment

Glioblastoma, the most malignant form of brain cancer, is responsible for 23% of primary brain tumors and has extremely poor outcome. Confounding the clinical management of glioblastomas is the extreme local invasiveness of these cancer cells. The mechanisms that govern invasion are poorly understood. To gain insight into glioblastoma invasion, we conducted experiments on the patterns of growth and dispersion of U87 glioblastoma tumor spheroids in a three-dimensional collagen gel. We studied two different cell lines, one with a mutation to the EGFR (U87DeltaEGFR) that is associated with increased malignancy, and one with an endogenous (wild-type) receptor (U87WT). We developed a continuum mathematical model of the dispersion behaviors with the aim of identifying and characterizing discrete cellular mechanisms underlying invasive cell motility. The mathematical model quantitatively reproduces the experimental data, and indicates that the U87WT invasive cells have a stronger directional motility bias away from the spheroid center as well as a faster rate of cell shedding compared to the U87DeltaEGFR cells. The model suggests that differences in tumor cell dispersion may be due to differences in the chemical factors produced by cells, differences in how the two cell lines remodel the gel, or different cell-cell adhesion characteristics.

Inhibition of matrix degrading enzymes and invasion in human glioblastoma (U87MG) cells by isoflavones

Glioblastoma multiforme is a primary brain tumor associated with extensive invasion into surrounding brain tissue. Matrix metalloproteinases (MMPs) and urokinase plasminogen activation (uPA) system are shown to be involved in tumor invasion as they help in degradation of extracellular matrix (ECM) proteins and thus assist in the movement of cells. MMP-2 and 9 were shown to be upregulated in gliomas, suggesting their involvement in invasion. Genistein and biochanin A are isoflavones commonly known as phytoestrogens and have some anticancer properties. We hypothesize that these two isoflavones can induce a lowering of tumor invasion by decreasing the activity of matrix degrading enzymes. In this study we investigated the effects of genistein and biochanin A on invasive activity of U87MG cells using the Calbiochem in vitro invasion assay system. Our results suggest that genistein and biochanin A induced a decrease in invasive activity of U87MG cells in a dose-related manner. Genistein also induced a decrease in EGF-stimulated invasion thereby implicating an involvement of EGF-mediated signaling in invasion. Our results also show that treatment of U87MG cells with the two isoflavones induced decreases in the enzymatic activity of MMP-9 and the protein levels of MT1-MMP and uPAR.

Inhibition of glioblastoma angiogenesis and invasion by combined treatments directed against vascular endothelial growth factor receptor-2, epidermal growth factor receptor, and vascular endothelial-cadherin

PURPOSE

Inhibition of angiogenesis can influence tumor cell invasion and metastasis. We previously showed that blockade of vascular endothelial growth factor receptor-2 (VEGFR-2) with the monoclonal antibody DC101 inhibited intracerebral glioblastoma growth but caused increased tumor cell invasion along the preexistent vasculature. In the present study, we attempted to inhibit glioma cell invasion using a monoclonal antibody against the epidermal growth factor receptor (EGFR), which in the context of human glioblastomas, has been implicated in tumor cell invasion. In addition, we analyzed whether blockade of vascular endothelial (VE)-cadherin as a different antiangiogenic target could also inhibit glioblastoma angiogenesis and growth.

EXPERIMENTAL DESIGNS

Nude mice who received intracerebral glioblastoma xenografts were treated using monoclonal antibodies against VEGFR-2 (DC101), EGFR (C225), and VE-cadherin (E4G10) either alone or in different combinations.

RESULTS

Increased tumor cell invasion provoked by DC101 monotherapy was inhibited by 50% to 66% by combined treatment with C225 and DC101. C225 inhibited glioblastoma cell migration in vitro, but had no effect on the volume of the main tumor mass or on tumor cell proliferation or apoptosis in vivo, either alone or in combination with DC101. The anti-VE-cadherin monoclonal antibody E4G10 was a weaker inhibitor of tumor angiogenesis and growth than DC101, and also caused a weaker increase in tumor cell invasion.

CONCLUSIONS

Inhibition of angiogenesis achieved by blocking either VEGFR-2 or VE-cadherin can cause increased glioma cell invasion in an orthotopic model. Increased tumor cell invasion induced by potent inhibition of angiogenesis with DC101 could be inhibited by simultaneous blockade of EGFR.

Genistein inhibits p38 map kinase activation, matrix metalloproteinase type 2, and cell invasion in human prostate epithelial cells

Epidemiologic studies associate consumption of genistein, in the form of dietary soy, with lower rates of metastatic prostate cancer. We have previously shown that genistein inhibits prostate cancer cell detachment in vitro, that it is well tolerated in an older cohort of men with prostate cancer, and that it alters cell signaling in that same cohort. We have also shown that p38 mitogen-activated protein kinase (MAPK) is necessary for transforming growth factor beta (TGF-beta)-mediated increases in prostate cancer adhesion. Although cell invasion is closely linked to metastatic behavior, little is known about how this process is regulated in prostate cancer or what effect, if any, genistein has on associated processes. We now show that genistein inhibits matrix metalloproteinase type 2 (MMP-2) activity in six of seven prostate cell lines tested, blocks MMP-2 induction by TGF-beta, and inhibits cell invasion. Efficacy was seen at low nanomolar concentrations, corresponding to blood concentrations of free genistein attained after dietary consumption. Inhibition of p38 MAPK by either SB203580 or dominant-negative construct blocked induction of MMP-2 and cell invasion by TGF-beta. Genistein exerted similar effects and was found to block activation of p38 MAPK by TGF-beta. This study shows that p38 MAPK is necessary for TGF-beta-mediated induction of MMP-2 and cell invasion in prostate cancer and that genistein blocks activation of p38 MAPK, thereby inhibiting processes closely linked to metastasis, and does so at concentrations associated with dietary consumption. Any potential causal link to epidemiologic findings will require further investigation.

DARP-36aa selectively promotes survival and morphological development of cultured mesencephalic neurons

We examined the effects of DARP-36aa on the survival and morphological development of embryonic rat mesencephalic neurons. Treatment of mesencephalic cultures with DARP-36aa, a synthetic peptide corresponding to the N terminal of dopamine-releasing protein (DARP), resulted in a 1.8-fold increase in neuron survival. Morphological analysis revealed that DARP-36aa-treated neurons contained 48% more branching points per neuron compared with controls. DARP-36aa selectively affected mesencephalic cultures; diencephalic and C6 glioma cells were not affected by DARP-36aa treatments. Mesencephalic cultures were also incubated with polyclonal antibodies against DARP-36aa (anti-DARP-36aa) to assess the effect of immunoneutralization of endogenous DARP on these cells. Mesencephalic cultures treated with anti-DARP-36aa contained 43% fewer neurons, and the number of branching points per neuron was decreased by nearly twofold compared with cultures grown with medium alone. Similar to cultures treated with DARP-36aa, immunoneutralization of DARP had no effect on any parameters examined in primary diencephalic and C6 glioma cultures. Mesencephalic cultures maintained in the presence of DARP-36aa had a 3.2-fold increase in the number of tyrosine hydroxylase (TH)-immunoreactive neurons, whereas anti-DARP-36aa incubations decreased TH-immunoreactive neurons by 40% compared with control cultures. Finally, coincubation of the specific tyrosine kinase inhibitor genistein with DARP-36aa resulted in a complete attenuation of DARP-36aa-mediated neuron survival and development in mesencephalic cultures. The findings indicate that DARP-36aa is a novel neurotrophic peptide that selectively promotes the survival and development of mesencephalic neurons.

Synergistic effect of genistein and BCNU on growth inhibition and cytotoxicity of glioblastoma cells

OBJECTIVE

Recent experiments have shown that dietary soy isoflavones such as genistein can significantly suppress invasiveness and growth of a number of human malignancies. This study examined whether genistein, at a concentration typical of plasma levels following soy diet intake, in combination with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) exhibited an additive or synergistic inhibitory effect on the growth of glioma cells.

METHODS

The human glioblastoma multiforme (GBM) cell line U87 and the rodent C6 glioma were treated with genistein at 4 microM, combined with BCNU (0-50 microM). Monolayer cell growth and cytotoxicity, as measured by colonigenic survival in soft agarose, were then compared in control and drug-treated cultures. Presence of apoptosis, using the DNA ladder assay and laser scanning cytometry (LSC), was investigated in all cell lines at those concentrations where an enhancement of antiproliferative effect of BCNU in presence of genistein was observed.

RESULTS

A 32-41% increase in monolayer growth inhibition and a 28-42% increase in colony cytotoxicity in the U87 cell line were observed when genistein (4 microM) was added to BCNU in the 0-10 microM dose range. In the C6 cell line, a 30-36% increase in monolayer growth inhibition and a 39-54% increase in colony cytotoxicity were observed with the BCNU dose range of 0-50 microM. All experiments showed a significant increase in growth inhibition and a decrease in colonogenic survival (P < 0.05). We were unable to detect apoptosis in any of the lines when genistein was combined with BCNU.

CONCLUSION

These results indicate that genistein at typical adult dietary plasma levels can significantly enhance the antiproliferative and cytotoxic action of BCNU. The implication for treatment of GBM may be a reduction in the chemotherapeutic dose recommendations of these agents and subsequently a decrease in the risk of treatment sequelae for these patients.

What role(s) for TGFalpha in the central nervous system?

Transforming growth factor alpha (TGFalpha) is a member of the epidermal growth factor (EGF) family with which it shares the same receptor, the EGF receptor (EGFR or erbB1). Identified since 1985 in the central nervous system (CNS), its functions in this organ have started to be determined during the past decade although numerous questions remain unanswered. TGFalpha is widely distributed in the nervous system, both glial and neuronal cells contributing to its synthesis. Although astrocytes appear as its main targets, mediating in part TGFalpha effects on different neuronal populations, results from different studies have raised the possibility for a direct action of this growth factor on neurons. A large array of experimental data have thus pointed to TGFalpha as a multifunctional factor in the CNS. This review is an attempt to present, in a comprehensive manner, the very diverse works performed in vitro and in vivo which have provided evidences for (i) an intervention of TGFalpha in the control of developmental events such as neural progenitors proliferation/cell fate choice, neuronal survival/differentiation, and neuronal control of female puberty onset, (ii) its role as a potent regulator of astroglial metabolism including astrocytic reactivity, (iii) its neuroprotective potential, and (iv) its participation to neuropathological processes as exemplified by astroglial neoplasia. In addition, informations regarding the complex modes of TGFalpha action at the molecular level are provided, and its place within the large EGF family is precised with regard to the potential interactions and substitutions which may take place between TGFalpha and its kindred.

Tumor biology and experimental therapeutics

Recent research using multicellular tumor spheroids has resulted in new insights in the regulation of invasion and metastasis, angiogenesis and cell cycle kinetics. The onset and expansion of central necrosis in tumor spheroids has been characterized to be a complex interaction of several mechanisms; in a number of cases, necrosis is not a consequence of hypoxia or anoxia, but emerges as secondary necrosis following an accumulation of apoptosis in spheroids. Recent therapeutically oriented studies have been directed towards novel hypoxic markers, targeted therapy, multicellular-mediated drug resistance, and heavy ion irradiation of spheroids. Research efforts should be enhanced mainly in the fields of tumor tissue modeling by heterotypic three-dimensional (3D) cultures and of apoptotic versus necrotic cell death. Based on the fundamental differences between monolayer and 3D cultures, spheroids should become mandatory test systems in therapeutic screening programs.

Brain tumor invasion rate measured in vitro does not correlate with Ki-67 expression

The need for more accurate prediction of the biological behavior of brain tumors has lead to the use of immunohistochemical methods for assessment of proliferating cell nuclear antigens such as Ki-67. There is a variable association of glioma Ki-67 labeling index with patient survival. Brain invasion by individual tumor cells also defines biological aggressiveness, and can be assessed in vitro. Further, proliferation and migration seem to be mutually exclusive behaviors for a given cell at a point in time. We studied the relationship between Ki-67 labeling index and invasion rate in a group of 10 gliomas, and 2 meningiomas. Human tumor spheroids obtained from operative specimen were co-cultured with fetal rat brain aggregates, and invasion rate was measured by confocal microscopic observation. There was no correlation between two measures of invasion and Ki-67 labeling. This finding supports the dichotomous nature of glioma proliferation and invasion, and may in part explain the limited usefulness of proliferation marker labeling.

Four-dimensional analysis of human brain tumor spheroid invasion into fetal rat brain aggregates using confocal scanning laser microscopy

The advent of confocal microscopy and fluorescence probes has made possible the routine visualization of the complex three-dimensional structures of thick fixed or live specimens. Four-dimensional (4-D) imaging of biological specimens (three-dimensional image reconstruction of the same living sample at different time points), remains a seldom-used application of confocal microscopy. In the present study we used 4-D imaging techniques to quantitate the invasion of human brain tumor spheroids into fetal rat brain aggregates (FRBAs), using the vital fluorescence membrane dyes, 3, 3'-Dioctadecyloxacarbocyanine perchlorate (DiO) and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) as visualization probes. We found invasion patterns similar to the in vivo behavior of these tumors in the brain. Glioblastoma spheroids showed diffuse and circumscribed infiltration accompanied by cystic degeneration or necrosis of FRBAs. Spheroids from cerebral metastasis, however, showed a sharp delimitation of the invasive margin, and did not penetrate the FRBA beyond a depth of 55 microns. Measured rates of glioblastoma invasion varied with the tumor specimens examined. The slopes of the mid-portions of plots of % infiltration vs. time (hours) for four glioblastoma cell lines were 1.7 +/- 0.21 (SD), 0.67 +/- 0.11, 1.4 +/- 0.22 and 1.3 +/- 0.18. We conclude that confocal microscopy with vital fluorescence probes is a practical method that allows for close monitoring and quantitation of the process of invasion in live tissue preparations, and may be used for assessing the in vitro effects of various tumor treatments.