Biological activities of a recombinant adenovirus p53 (SCH 58500) administered by hepatic arterial infusion in a Phase 1 colorectal cancer trial

The major focus of intrahepatic arterial (IHA) administration of adenoviruses (Ad) has been on safety. Currently, there is little published data on the biological responses to Ad when administered via this route. As part of a Phase I study, we evaluated biological responses to a replication-defective adenovirus encoding the p53 transgene (SCH 58500) when administered by hepatic arterial infusion to patients with primarily colorectal cancer metastatic to the liver. In analyzing biological responses to the Ad vector, we found that both total and neutralizing Ad antibodies increased weeks after SCH 58500 infusion. The fold increase in antibody titers was not dependent on SCH 58500 dosage. The proinflammatory cytokine interleukin-6 (IL-6) transiently peaked within 6 h of dosing. The cytokine sTNF-R2 showed elevation by 24 h post-treatment, and fold increases were directly related to SCH 58500 doses. Cytokines TNF-alpha, IL-1beta, and sTNF-R1 showed no increased levels over 24 h. Predose antibody levels did not appear to predict transduction, nor did serum Ad neutralizing factor (SNF). Delivery of SCH 58500 to tumor tissue occurred, though we found distribution more predominantly in liver tissues, as opposed to tumors. RT-PCR showed significantly higher expression levels (P<0.0001, ANOVA) for adenovirus type 2 and 5 receptor (CAR) in liver tissues, suggesting a correlation with transduction. Evidence of tumor-specific apoptotic activity was provided by laser scanning cytometry, which determined a coincidence of elevated nuclear p53 protein expression with apoptosis in patient tissue. IHA administration of a replication defective adenovirus is a feasible mode of delivery, allowing for exogenous transfer of the p53 gene into target tissues, with evidence of functional p53. Limited and transient inflammatory responses to the drug occurred, but pre-existing immunity to Ad did not preclude SCH 58500 delivery.

Relationship between regional cerebral metabolism and consciousness disturbance in traumatic diffuse brain injury without large focal lesions: an FDG-PET study with statistical parametric mapping analysis

BACKGROUND

The cerebral metabolism of patients in the chronic stage of traumatic diffuse brain injury (TDBI) has not been fully investigated.

AIM

To study the relationship between regional cerebral metabolism (rCM) and consciousness disturbance in patients with TDBI.

METHODS

52 patients with TDBI in the chronic stage without large focal lesions were enrolled, and rCM was evaluated by fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) with statistical parametric mapping (SPM). All the patients were found to have disturbed consciousness or cognitive function and were divided into the following three groups: group A (n = 22), patients in a state with higher brain dysfunction; group B (n = 13), patients in a minimally conscious state; and group C (n = 17), patients in a vegetative state. rCM patterns on FDG-PET among these groups were evaluated and compared with those of normal control subjects on statistical parametric maps.

RESULTS

Hypometabolism was consistently indicated bilaterally in the medial prefrontal regions, the medial frontobasal regions, the cingulate gyrus and the thalamus. Hypometabolism in these regions was the most widespread and prominent in group C, and that in group B was more widespread and prominent than that in group A.

CONCLUSIONS

Bilateral hypometabolism in the medial prefrontal regions, the medial frontobasal regions, the cingulate gyrus and the thalamus may reflect the clinical deterioration of TDBI, which is due to functional and structural disconnections of neural networks rather than due to direct cerebral focal contusion.

Evidence for white matter disruption in traumatic brain injury without macroscopic lesions

BACKGROUND

Non-missile traumatic brain injury (nmTBI) without macroscopically detectable lesions often results in cognitive impairments that negatively affect daily life.

AIM

To identify abnormal white matter projections in patients with nmTBI with cognitive impairments using diffusion tensor magnetic resonance imaging (DTI).

METHODS

DTI scans of healthy controls were compared with those of 23 patients with nmTBI who manifested cognitive impairments but no obvious neuroradiological lesions. DTI was comprised of fractional anisotropy analysis, which included voxel-based analysis and confirmatory study using regions of interest (ROI) techniques, and magnetic resonance tractography of the corpus callosum and fornix.

RESULTS

A decline in fractional anisotropy around the genu, stem and splenium of the corpus callosum was shown by voxel-based analysis. Fractional anisotropy values of the genu (0.47), stem (0.48), and splenium of the corpus callosum (0.52), and the column of the fornix (0.51) were lower in patients with nmTBI than in healthy controls (0.58, 0.61, 0.62 and 0.61, respectively) according to the confirmatory study of ROIs. The white matter architecture in the corpus callosum and fornix of patients with nmTBI were seen to be coarser than in the controls in the individual magnetic resonance tractography.

CONCLUSIONS

Disruption of the corpus callosum and fornix in patients with nmTBI without macroscopically detectable lesions is shown. DTI is sensitive enough to detect abnormal neural fibres related to cognitive dysfunction after nmTBI.

p53-Independent ceramide formation in human glioma cells during gamma-radiation-induced apoptosis

Although the p53 tumor-suppressor gene product plays a critical role in apoptotic cell death induced by DNA-damaging chemotherapeutic agents, human glioma cells with functional p53 were more resistant to gamma-radiation than those with mutant p53. U-87 MG cells with wild-type p53 were resistant to gamma-radiation. U87-W E6 cells that lost functional p53, by the expression of type 16 human papillomavirus E6 oncoprotein, became susceptible to radiation-induced apoptosis. The formation of ceramide by acid sphingomyelinase (A-SMase), but not by neutral sphingomyelinase, was associated with p53-independent apoptosis. SR33557 (2-isopropyl-1-(4-[3-N-methyl-N-(3,4-dimethoxybphenethyl)amino]propyloxy)benzene-sulfonyl) indolizine, an inhibitor of A-SMase, suppressed radiation-induced apoptotic cell death. In contrast, radiation-induced A-SMase activation was blocked in glioma cells with endogenous functional p53. The expression of acid ceramidase was induced by gamma-radiation, and was more evident in cells with functional p53. N-oleoylethanolamine, which is known to inhibit ceramidase activity, unexpectedly downregulated acid ceramidase and accelerated radiation-induced apoptosis in U87-W E6 cells. Moreover, cells with functional p53 could be sensitized to gamma-radiation by N-oleoylethanolamine, which suppressed radiation-induced acid ceramidase expression and then enhanced ceramide formation. Sensitization to gamma-radiation was also observed in U87-MG cells depleted of functional p53 by retroviral expression of small interfering RNA. These results indicate that ceramide may function as a mediator of p53-independent apoptosis in human glioma cells in response to gamma-radiation, and suggest that p53-dependent expression of acid ceramidase and blockage of A-SMase activation play pivotal roles in protection from gamma-radiation of cells with endogenous functional p53.

Discrepancy between lesion distributions on methionine PET and MR images in patients with glioblastoma multiforme: insight from a PET and MR fusion image study

OBJECTIVE

To examine (11)C-methyl methionine (MET) accumulation on positron emission tomographic (PET) imaging of glioblastoma multiforme to determine the distribution of metabolic abnormality compared with magnetic resonance imaging (MRI).

METHODS

Contemporaneous MRI was superimposed on corresponding MET-PET images in 10 patients with newly diagnosed glioblastoma multiforme before treatment. Differences between the extended area of MET accumulation on PET imaging (MET area), the gadolinium (Gd) enhanced area on T1 weighted images (Gd area), and the abnormal high signal intensity area on T2 weighted images (T2-high area) were assessed.

RESULTS

The MET area was larger than the Gd area and included the entire Gd area. The discrepancy in volume between the MET and Gd areas became greater with increasing tumour diameter. On average, 58.6% of the MET area was located within the Gd area, 90.1% within 10 mm outside the Gd area, 98.1% within 20 mm, and 99.8% within 30 mm. A newly developed Gd area had emerged in five of the 10 cases up to the time of study. In three of the five cases this was in the MET area even after complete surgical resection of the Gd area on the initial MRI; in the remaining two it originated in the residual Gd area after surgery. In all cases, the T2-high area was larger than the MET area. The MET area extended partly beyond the T2-high area in nine cases, and was completely within it in one.

CONCLUSIONS

Glioblastoma multiforme cells may extend over the Gd area and more widely with increasing tumour size on Gd-MRI. The T2-high area includes the greater part of the tumour but not its entire area. The methods reported may be useful in planning surgical resection, biopsy, or radiosurgery.

Molecular mechanisms of TNF-α-induced ceramide formation in human glioma cells:P53-mediated oxidant stress-dependent and -independent pathways

The present study was designed to examine the roles of p53, reactive oxygen species (ROS), and ceramide, and to determine their mutual relationships during tumor necrosis factor (TNF)-alpha-induced apoptosis of human glioma cells. In cells possessing wild-type p53, TNF-alpha stimulated ceramide formation via the activation of both neutral and acid sphingomyelinases (SMases), accompanied by superoxide anion (O2-*) production, and induced mitochondrial depolarization and cytochrome c release, whereas p53-deficient cells were partially resistant to TNF-alpha and lacked O2-* generation and neutral SMase activation. Restoration of functional p53 sensitized glioma cells expressing mutant p53 to TNF-alpha by accumulation of O2-*. z-IETD-fmk (benzyloxycarbonyl-Ile-Glu-Thr-Asp fluoromethyl ketone), but not z-DEVD-fmk (benzyloxycarbonyl-Asp-Glu-Val-Asp fluoromethyl ketone), blocked TNF-alpha-induced ceramide formation through both SMases as well as O2-* generation. Caspase-8 was processed by TNF-alpha regardless of p53 status of cells or the presence of antioxidants. Two separate signaling cascades, p53-mediated ROS-dependent and -independent pathways, both of which are initiated by caspase-8 activation, thus contribute to ceramide formation in TNF-alpha-induced apoptosis of human glioma cells.

Glioma tumourgenicity is decreased by iNOS knockout: experimental studies using the C6 striatal implantation glioma model

Nitric oxide synthase (NOS) has recently been shown to be an important pathophysiological regulator in experimental implantation glioma since manipulation of NOS can significantly alter tumoural blood flow and inhibit tumour growth. In this study we investigated the role of iNOS (inducible NOS) in glioma tumourogenisis using the rodent C6 striatal implantation model. We produced genetically engineered C6 clones that do not express iNOS activity even after stimulation with a mixture of lipopolysaccaride (LPS) and tumour necrosis factor (TNF)-alpha. These iNOS knockout cells showed a similar growth rate to control cells in vivo at 5 days. We then performed an in vivo implantation glioma study using either the iNOS knockout clone or two genetically engineered control C6 clones. There was a significant reduction (p < 0.01) of tumour mass with the iNOS knockout clone 28 days after the implantation. Immunocytochemistry indicated infiltrates of CD3 positive T cells and macrophages in the controls and the iNOS knockout group. These studies indicate that iNOS expression by tumour parenchymal cells is a critical factor for tumour growth with this model. The mechanisms that cause failure of tumour growth need clarification prior to considering that specific iNOS inhibitors might be candidates for adjuvant treatment of malignant glioma.

Expression of hepatocyte growth factor and matrix metalloproteinase-2 in human glioma

Hepatocyte growth factor (HGF) has a stimulatory effect on the synthesis of matrix metalloproteinase-2 (MMP-2), which is involved in glioma invasion. In this study, to clarify the correlation between the expression of HGF and MMP-2 in glioma tissues, immunohistochemical analysis of HGF and MMP-2 was performed in 11 cases of astrocytoma, 10 cases of anaplastic astrocytoma, and 9 cases of glioblastoma. As a result, expression of HGF and MMP-2 was correlated with the grade of malignancy (P = 0.0181 and 0.0001, respectively), and a significant correlation between the immunoreactivity of HGF and that of MMP-2 was observed (P < 0.05). Immunofluorescence study revealed the concomitant expression of HGF and MMP-2 in glioma tissue. In cultured glioma cell lines (SNB-19, U87MG, and U373MG), exogenous recombinant HGF effectively acted on the production of the active and latent forms of MMP-2 protein in a dose-dependent manner. Active MMP-2 increased more effectively than the latent form. Taken together, these results suggest that HGF may promote glioma invasion in vivo by production of MMP-2.

Interferon alpha2b gene delivery using adenoviral vector causes inhibition of tumor growth in xenograft models from a variety of cancers

A recombinant adenovirus expressing human interferon alpha2b driven by the cytomegalovirus promoter, IACB, was shown to produce and secrete biologically active protein in vitro and in vivo. Intravenous administration of IACB in Buffalo rats resulted in circulating levels of biologically active human interferon at 70,000 international units/mL for up to 15 days. Distribution of interferon protein after IACB administration was different from that seen with the subcutaneous delivery of interferon protein. Higher levels of interferon protein were observed in liver and spleen after IACB delivery compared to protein delivery. The antitumor efficacy of IACB, as measured by suppression of tumor growth, was tested in athymic nude mice bearing established human tumor xenografts from different types of human cancer. Subcutaneous tumors most responsive to the intratumoral administration of IACB ranked as U87MG (glioblastoma) and K562 (chronic myelogenous leukemia), followed by Hep 3B (hepatocellular carcinoma) and LN229 cells (glioblastoma). Intravenous administration of IACB in animals bearing U87MG or Hep 3B xenografts was also effective in suppressing tumor growth, although to a lesser extent than the intratumoral administration. IACB was also tested in a metastatic model in beige/SCID mice generated with H69 (small cell lung carcinoma) cells and was found to prolong survival in tumor-bearing animals. This suggested that interferon gene delivery can be effective in suppressing tumor growth in a wide variety of cells.

Adenoviral delivery of human and viral IL-10 in murine sepsis

Adenovirus (Ad) gene therapy has been proposed as a drug-delivery system for the targeted administration of protein-based therapies, including growth factors and biological response modifiers. However, inflammation associated with Ad transduction has raised concern about its safety and efficacy in acute inflammatory diseases. In the present report, intratracheal and i.v. administration of a first-generation adenoviral recombinant (E1,E3 deleted) either containing an empty cassette or expressing the anti-inflammatory cytokines viral or human IL-10 (IL-10) was administered to mice subjected to zymosan-induced multisystem organ failure or to acute necrotizing pancreatitis. Pretreatment of mice with the intratracheal instillation of Ad expressing human IL-10 or viral IL-10 reduced weight loss, attenuated the proinflammatory cytokine response, and reduced mortality in the zymosan-induced model, whereas pretreatment with a control adenoviral recombinant did not significantly exacerbate the response. Pretreatment of mice with pancreatitis using adenoviral vectors expressing IL-10 significantly reduced the degree of pancreatic and liver injury and liver inflammation when administered systemically, but not intratracheally. We conclude that adenoviral vectors can be administered prophylactically in acute inflammatory syndromes, and expression of the anti-inflammatory protein IL-10 can be used to suppress the underlying inflammatory process.

Chordoid meningioma

Chordoid meningioma is a relatively rare variant that is often associated with peritumoral lymphoplasmacellular infiltration causing Castleman syndrome (CS). We present a 44-year-old woman with chordoid meningioma not associated with CS. The patient presented with epilepsy and right hemiparesis (Todd's palsy) on admission. The radiological findings revealed an extraaxial mass lesion in the premotor cortex. They were compatible with a preoperative diagnosis of meningioma. No physical abnormalities related to CS were detected. A left frontal craniotomy was performed. The tumor surface was gelatinous, and it was totally resected with the attached dura mater (Simpson grade I). The patient had an uneventful recovery, and her seizures subsided. The pathological findings of the specimens revealed nests and cords of spindle and epithelioid cells with abundant myxoid matrix, mimicking the features of chordoma. On the basis of radiological, immunohistochemical, and electron microscopic findings, chordoid meningioma was verified, and a review of the literature was performed.

Nitric oxide and glioma: a target for novel therapy?

The biological activities of nitric oxide (NO) include vasodilatation, inhibition of platelet aggregation, neurotransmission, neural plasticity, and modulation of inflammatory and immunological functions. NO synthase (NOS), which is the enzyme that produces NO, has been detected in resected human glioma specimens, and both human and rodent glioma cell lines. NO production in gliomas can alter several important pathophysiological processes, such as local host immune response, tumour cell apoptosis, tumour invasion/metastasis, free radical injury to tumour cells and adjacent normal brain tissues, tonic vasodilatation of tumour vessels, vascular permeability and neovascularization. Recently, some therapeutic strategies for gliomas using NO manipulation have been proposed, and evaluated both experimentally and indirectly in preliminary clinical trials. These include NO manipulation designed to modify tumour cell oncogenesis, tumour blood flow and disposition of anti-cancer drugs in tumour tissue. This review will discuss the biological role of NO in the central nervous system and gliomas and its current and future possibilities in neuro-oncology.

Selection of eligible patients with supratentorial glioblastoma multiforme for gross total resection

The purpose of this study is to clarify whether gross total tumor resection can prolong the survival in adult patients with supratentorial glioblastoma multiforme (GBM), and to clarify what subset of these patients obtains a survival advantage by gross total tumor resection without postoperative neurological deterioration. Eighty-two adult patients with supratentorial GBM were retrospectively reviewed. Overall, the median survival time was 13 months, and the 1- and 2-year survival rates were 53.7% and 14.6%, respectively. In a univariate analysis for survival rate by log-rank test, age (< 40 years), Karnofsky performance scale (KPS) score (70-100%) and extent of surgery (gross total resection) were revealed to be significant good prognostic factors. A Cox proportional hazard multivariate regression analysis confirmed that the KPS and extent of surgery were independent, significant good prognostic factors. Nine patients (11%) suffered postoperative neurological deterioration. A topographical GBM staging system (Stages I, II and III) with the integration of tumor location, size and eloquence of adjacent brain based on MRI (for explanation of Stages see text) was originally proposed. In Stage I, gross total resection had a strong tendency toward a better prognostic factor in a univariate analysis and was revealed to be a significant independent good prognostic factor in a multivariate analysis. In also Stage II, the survival of patients who underwent gross total resection was better than that of patients with less than gross total resection, although not significant. In Stage III, there were no patients who underwent gross total tumor resection. Risk probabilities of postoperative neurological deterioration, overall, were 0%, 22.2%, and 20% in Stages I, II, and III, respectively, and those after gross total resection were 0% and 16.7% in Stages I and II, respectively. Although gross total tumor resection is associated with prolongation of the survival time of patients with GBM, the risk of postoperative neurological deficit increases with radical tumor resection. To select an eligible subset of patients that benefit in survival from gross total tumor resection without postoperative risk, the following surgical policy for GBM resection is suggested. GBM in Stage I should be resected as radically as possible. Regarding Stage II, risky surgical resection extending to the area adjacent to the critical zone should be avoided and more meticulous and careful surgical planning is needed than that in Stage I. In Stage III, radical gross total tumor resection is not recommended at present.

p53 regulates ceramide formation by neutral sphingomyelinase through reactive oxygen species in human glioma cells

The present study was designed to elucidate the relationship between p53 and ceramide, both of which are involved in apoptotic signaling. Treatment of human glioma cells with etoposide caused apoptosis only in cells expressing functional p53. p53 activation was followed by the formation of reactive oxygen species (ROS), superoxide anion (O2-*) measured by hydroethidium oxidation into ethidium and hydrogen peroxide (H2O2) measured by oxidation of 2',7'-dichlorofluorescin (DCFH) into 2',7'-dichlorofluorescein (DCF), which was accompanied with ceramide generation through the activation of neutral, but not acid, sphingomyelinase. Superoxide dismutase (SOD), a selective antioxidant for O2-*, had no effects on p53 expression but inhibited ceramide generation and apoptotic cell death caused by etoposide. However, catalase, a specific antioxidant for H2O2, only weakly inhibited and sodium formate, a hydroxyl radical (* OH) scavenger, unaffected etoposide-induced apoptosis. Like etoposide-induced cell death, treatment of glioma cells with the O2-*-releasing agent, pyrogallol, induced typical apoptosis and ceramide generation even in the presence of catalase. In contrast, human glioma cells lacking functional p53, either due to mutation or the expression of E6 protein of human papillomavirus, were highly resistant to etoposide and exhibited no significant change in the ceramide level. Moreover, expression of functional p53 protein in glioma cells expressing mutant p53 using a temperature-sensitive human p53(Val138) induced ceramide accumulation by the activation of neutral sphingomyelinase which was dependent on the generation of O2-*. Taken together, these results suggest that p53 may modulate ceramide generation by activation of neutral sphingomyelinase through the formation of O2-*, but not its downstream compounds H2O2 or * OH.

Effects of risperidone on event-related potentials in schizophrenic patients

In order to examine the effects of risperidone on cognitive impairment in schizophrenia, event-related potentials (ERPs) were recorded before and after switching from conventional neuroleptics to risperidone in schizophrenic patients. ERPs were recorded during two auditory discrimination tasks (an oddball task and a distraction task) in 10 medicated schizophrenic patients during conventional neuroleptic and risperidone treatments. The amplitudes and latencies of N 100 and P300 component were measured in ERPs for target stimuli in the oddball task and in ERPs for target and novel stimuli in the distraction task. Although N 100 amplitude and latency and P 300 amplitude did not change significantly after switching the drug compared to that during conventional neuroleptic treatment, P 300 latency for target stimuli shortened significantly during risperidone treatment in both tasks, accompanied by the shortening of the reaction time in the distraction task. The P 300 latency change did not correlate with the change of the severity of psychopathology. These findings suggest that risperidone may speed the information processing in schizophrenic patients, contributing to the improvement of cognitive functions.

The effects of dexamethasone therapy on permeability, blood flow and iNOS expression in experimental glioma

Most studies of dexamethasone (DXN) effects on experimental glioma have used doses 10-500 higher (on mg/kg basis) than those used for patients with brain tumour. The relevance of findings to patients with glioma are therefore uncertain. In order to evaluate the effects of clinical doses of DXN (0.22 mg kg(-1)day(-1)) on the pathophysiology of an experimental glioma we have treated rodents with established C6 gliomas for 3 days. The effects of therapy on local cerebral blood flow (LCBF), tumour blood flow (TBF), tumour capillary permeability (TCP), and inducible nit ric oxide synthase (iNOS) mRNA expression were evaluated. DXN caused a significant reduction in TCP (21 +/- 1.9 to 7.7 +/- 2.2 ml.gm(-1)min(-1)10(-3)) and iNOS mRNA production within and around tumour, but no significant change in either TBF or LCBF. The reduction in TCP was identical to that reported after higher doses of DXN and is probably mediated by glucocorticoid receptors. Further in vivo stud ies using either behavioural or neuropathological paradigms in rodents with established cerebral glioma should be treated with similar doses of DXN to optimise clinical relevance.

The effects of chronic nitric oxide synthase suppression on glioma pathophysiology

Nitric oxide synthase (NOS) is strongly expressed in glioma and has an important role in tumour blood flow (TBF) regulation. Whether manipulation of NOS function within a tumour can have any therapeutic effect is unknown. This study therefore evaluated the pathophysiological effects of chronic systemic NOS inhibition on experimental rodent glioma blood flow, growth and necrosis. To determine the duration and pathophysiological effects of systemic NOS inhibition, Ng-nitro-L-arginine methyl ester (L-NAME) was given to rats bearing C6 glioma acutely (single dose i.v., 30 mg kg) or for either 4 or 7 days (i.p. 75 mg kg day) prior to study. TBF and local cerebral blood flow (LCBF) were measured using C14-iodoantipyrine quantitative autoradiography. Tumour volume, tumoural necrosis and tumoural NOS were measured using conventional neuropathology and immunocytochemistry. Acute and 4-day L-NAME administration produced significant TBF reductions (-48 and -39%, respectively) with less marked changes in LCBF (-35 and -15%, respectively). Seven-day L-NAME administration reduced tumour volume (p = 0.12), increased tumoural necrosis (p < 0.05), but immunohistochemistry showed no difference in tumoural NOS expression. These results confirm that NOS has a significant role in the pathophysiology of experimental glioma, and that in this glioma model the effects of chronic systemic NOS inhibition are, for the period under study, predominately anti-tumoural. Whether chronic NOS inhibition is useful as an adjunct in glioma therapy or provides the opportunity for novel therapeutic approaches requires further study.

Differential expression of beta-catenin in human glioblastoma multiforme and normal brain tissue

Angiogenesis is considered to play an important role in the development of malignant brain tumors, especially glioblastoma multiforme (GBM). Abnormal vascular construction with a glomeruloid appearance is characteristic of GBM. beta-catenin is known as one of the adhesive molecules associated not only with cell adhesion and cell polarity, but also with carcinogenesis. We postulated the relevance of beta-catenin to vigorous endothelial proliferation in human GBM because the vascular cells (VCs) are apt to lose their cell polarity. The object of this study is to compare the immunohistochemical localization of beta-catenin in VCs between GBMs and normal brain tissues. Immunohistochemical analysis of beta-catenin for VCs in 32 GBMs and 10 normal brain tissues was performed. beta-catenin was found concentrated in the areas of vascular cell-cell junction and internal surface of the vascular lumen in all normal brains. In contrast, beta-catenin, in proliferating VCs in GBMs, was stained homogeneously and intensely in the cytoplasms of 26 cases (81.3%), in which nuclear staining of beta-catenin was also recognized in four cases (12.5%). In conclusion, the intracellular localization of beta-catenin in VCs of GBMs was found to be different from that of normal brain tissues. The changes of expression of beta-catenin may be associated with the angiogenesis or transformation of the VCs in human GBM.

Influence of Bax or Bcl-2 overexpression on the ceramide-dependent apoptotic pathway in glioma cells

Ceramide has recently been regarded as a potential mediator of apoptosis. In the present study, the effects of Bcl-2 and Bax on the ceramide-mediated apoptotic pathways were examined in glioma cells overexpressing Bcl-2 or Bax. Etoposide, cisplatin and tumor necrosis factor-alpha induced apoptosis of C6 rat glioma cells which was associated with ceramide formation due to activation of neutral sphingomyelinase, followed by release of mitochondrial cytochrome c into the cytosol and activation of caspases-9 and -3. The growth of C6 cells stably overexpressing either Bcl-2 or Bax was almost equal to that of the vector-transfected cells. Bax overexpression enhanced etoposide-induced apoptosis through acceleration of cytochrome c release and caspases activation. However, Bax had no effect on ceramide formation. Similar findings were obtained in C6 cells and U87-MG human glioblastoma cells which were transiently overexpressed with Bax. In contrast, Bcl-2 overexpression resulted in a retardation of the apoptotic process via prevention of cytochrome c release and caspases activation, and ceramide formation was also blocked when Bcl-2 was highly overexpressed in glioma cells. In addition, transient overexpression of Bcl-xL also exerted inhibitory effects on ceramide formation and apoptotic cell death induced by etoposide. These results indicate that Bax promotes apoptosis regardless of ceramide formation and that Bcl-2 or Bcl-xL prevents ceramide formation by repressing neutral sphingomyelinase as well as ceramide-induced cytochrome c release. Oncogene (2000) 19, 3508 - 3520

Immunohistochemical analysis of beta-catenin in N-ethyl-N-nitrosourea-induced rat gliomas: implications in regulation of angiogenesis

Angiogenesis plays an important role in the development of malignant brain tumors. We postulated the involvement of beta-catenin, which is associated with not only cell adhesion but also tumorigenesis in some neoplasms, in angiogenesis in brain tumors. We performed an immunohistochemical analysis of beta-catenin for vascular cells (VC) in 45 N-ethyl-N-nitrosourea (ENU)-induced rat gliomas and rat normal brain tissues. As a result, beta-catenin was found concentrated in the vascular cell-cell junction and internal surface of the vascular lumen in all normal brains. In contrast, proliferating VC in tumors were stained homogeneously in the cytoplasms of 35 cases (77.8%), among which nuclear staining was also recognized in 12 cases (26.7%). The proliferative potential of VC, which was evaluated by nucleolar organizer region-associated argyrophilic protein (AgNOR), was higher in all types of tumors than in normal brains, and was basically in parallel with the degree of malignancy of the tumors. Thus, it was suggested that the tumor vessels proliferate under a relationship with the proliferative potential of the tumors, and the intracellular localization of beta-catenin is changed under the influence of proliferative potentials of VC. beta-catenin in normal VC is considered to maintain the polarity of the vascular structure, and thus aberrant localization of beta-catenin may result in the loss of structural polarity of the tumor vessels.

Diagnostic utility of CSF soluble CD27 for primary central nervous system lymphoma in immunocompetent patients

The aim of this study is to determine the diagnostic utility of cerebrospinal fluid (CSF) soluble CD27 (sCD27) as a tumor marker for primary central nervous system lymphoma (PCNSL) in immunocompetent patients. A total of 93 CSF samples were collected from the following four patient groups: the PCNSL group, 13 patients (26 samples) with PCNSL, 12 samples obtained at initial diagnosis, 10 during therapy, four at complete remission; the other brain tumors (OBT) group, 30 patients (30 samples) with other brain tumors; the other neurological diseases (OND) group, 25 (25 samples) with other neurological diseases; the inflammatory neurological diseases (IND) group, 12 patients (12 samples) with inflammatory neurological diseases. sCD27 levels were determined by sandwich enzyme-linked immunosorbent assay. The optimal cut-off value was found to be 15 U ml-1. The CSF sCD27 levels were over 15 U ml-1 in 23 of the 26 PCNSL samples and were significantly higher than those in the OBT and OND groups in which all samples were below 15 U ml-1. Elevated CSF sCD27 levels were also observed in 11 of 12 IND samples. In the two PCNSL patients whose CSF sCD27 levels were studied longitudinally, the sCD27 levels correlated very well with remission and relapse of the disease. CSF sCD27 is useful as a tumor marker for PCNSL in immunocompetent patients, and is also useful to evaluate the effect of various types of treatment. Although there was a large cross-reactivity in the CSF sCD27 levels between PCNSL and IND group, white blood cell count in the CSF is helpful to distinguish these two diseases.

Intra-operative optical method using intrinsic signals for localization of sensorimotor area in patients with brain tumor

The purpose of this study is intra-operatively to localize the sensorimotor area by intrinsic optical method detecting the changes in regional cerebral blood flow (rCBF) and cortical temperature following neuronal activity during median nerve stimulation. In 18 patients with brain tumors located around the sensorimotor cortex, cortical recording of somatosensory evoked potentials (SEPs) was performed and localized changes in rCBF during median nerve stimulation were measured by a laser-Doppler flowmeter on the locations of SEPs and around the activation area obtained by functional magnetic resonance imaging (fMRI). In two patients, cortical thermomapping was also performed during median nerve stimulation. In fMRI study, the significant activation area of sensorimotor could be obtained in 17 of 18 patients. In cortical recording of SEPs, the polarity reversal of N20 and P20 was observed in 14 of the 18 patients. In 9 of the 14 patients in whom SEPs could be recorded, the localized changes in rCBF, corresponding to the stimulation, were detected in the N20 area. In 2 of the 4 patients in whom N20 could not be recorded successfully, the localized changes in rCBF could be detected. The increase in rCBF during the stimulation was 18.3% +/- 5.3% (mean +/- SD, n = 11). Thermomapping could demonstrate the localized area, where the increase in rCBF was also detected, by observation of the changes in cortical temperature during the stimulation. The intra-operative intrinsic optical method detecting rCBF and cortical temperature in combination with recording of SEPs may be considered useful for brain functional localization related to neurosurgical disorders.

Effect of ceramide on interleukin-6 synthesis in osteoblast-like cells

We previously showed that prostaglandin (PG) E1 stimulates the synthesis of interleukin-6 (IL-6) through activation of protein kinase (PK) A in osteoblast-like MC3T3-E1 cells and that PGF2alpha induces IL-6 synthesis through PKC activation. In other studies, we demonstrated that thrombin stimulates IL-6 synthesis, which depends on intracellular Ca2+ mobilisation in these cells and that tumour necrosis factor-alpha (TNF) induces IL-6 synthesis through sphingosine 1-phosphate, a product of sphingomyelin turnover. In the present study, among sphingomyelin metabolites, we examined the effect of ceramide on the IL-6 synthesis induced by various agonists in MC3T3-E1 cells. C2-ceramide, a cell-permeable ceramide analogue, suppressed the PGE1-induced IL-6 synthesis. C2-ceramide inhibited the IL-6 synthesis induced by PGF2alpha or 12-O-tetradecanoylphorbol-13-acetate, an activator of PKC. C2-ceramide reduced the IL-6 synthesis induced by cholera toxin, forskolin or dibutyryl cAMP. C2-ceramide inhibited the IL-6 synthesis induced by thrombin. The IL-6 synthesis stimulated by thapsigargin, which is known to stimulate Ca2+ mobilisation from intracellular Ca2+ stores, or A23187, a Ca-ionophore, was also inhibited by C2-ceramide. C2-ceramide did not affect the IL-6 synthesis induced by interleukin-1. On the contrary, C2-ceramide enhanced the TNF-induced IL-6 synthesis. D,L-threo-dihydrosphingosine, an inhibitor of sphingosine kinase, inhibited the enhancement by C2-ceramide as well as the TNF-effect. These results strongly suggest that ceramide modulates the IL-6 synthesis stimulated by various agonists in osteoblasts.