Loss of AP-2 results in downregulation of c-KIT and enhancement of melanoma tumorigenicity and metastasis

Expression of the tyrosine kinase receptor, c-KIT, progressively decreases during local tumor growth and invasion of human melanomas. We have previously shown that enforced c-KIT expression in highly metastatic cells inhibited tumor growth and metastasis in nude mice. Furthermore, the ligand for c-KIT, SCF, induces apoptosis in human melanoma cells expressing c-KIT under both in vitro and in vivo conditions. Here we show that loss of c-KIT expression in highly metastatic cells correlates with loss of expression of the transcription factor AP-2. The c-KIT promoter contains three binding sites for AP-2 and EMSA gels demonstrated that AP-2 protein binds directly to the c-KIT promoter. Transfection of wild-type AP-2 into c-KIT-negative A375SM melanoma cells activated a c-KIT promoter-driven luciferase reporter gene, while expression of a dominant-negative AP-2B in c-KIT-positive Mel-501 cells inhibited its activation. Endogenous c-KIT mRNA and expression of proteins were upregulated in AP-2-transfected cells, but not in control cells. In addition, re-expression of AP-2 in A375SM cells suppressed their tumorigenicity and metastatic potential in nude mice. These results indicate that the expression of c-KIT is highly regulated by AP-2 and that enforced AP-2 expression suppresses tumorigenicity and metastatic potential of human melanoma cells, possibly through c-KIT transactivation and SCF-induced apoptosis. Therefore, loss of AP-2 expression might be a crucial event in the development of malignant melanoma.

Loss of AP-2 results in up-regulation of MCAM/MUC18 and an increase in tumor growth and metastasis of human melanoma cells

MCAM/MUC18 is a cell-surface glycoprotein of 113 kDa, originally identified as a melanoma antigen, whose expression is associated with tumor progression and the development of metastatic potential. We have previously shown that enforced expression of MCAM/MUC18 in primary cutaneous melanoma led to increased tumor growth and metastatic potential in nude mice. The mechanism for up-regulation of MCAM/MUC18 during melanoma progression is unknown. Here we show that up-regulation of MCAM/MUC18 expression in highly metastatic cells correlates with loss of expression of the transcription factor AP-2. The MCAM/MUC18 promoter contains four binding sites for AP-2, and electrophoretic mobility shift assay gels demonstrated that the AP-2 protein bound directly to the MCAM/MUC18 promoter. Transfection of AP-2 into highly metastatic A375SM melanoma cells (AP-2-negative and MCAM/MUC18-positive) inhibited MCAM/MUC18 promoter-driven chloramphenicol acetyltransferase reporter gene in a dose-dependent manner. MCAM/MUC18 mRNA and protein expression were down-regulated in AP-2-transfected but not in control cells. In addition, re-expression of AP-2 in A375SM cells inhibited their tumorigenicity and metastatic potential in nude mice. These results indicate that the expression of MCAM/MUC18 is regulated by AP-2 and that enforced AP-2 expression suppresses tumorigenicity and metastatic potential of human melanoma cells, possibly by down-regulating MCAM/MUC18 gene expression. Since AP-2 also regulates other genes that are involved in the progression of human melanoma such as c-KIT, E-cadherin, MMP-2, and p21(WAF-1), we propose that loss of AP-2 is a crucial event in the development of malignant melanoma.

Dominant-negative CREB inhibits tumor growth and metastasis of human melanoma cells

The ATF/CREB family of eukaryotic transcription factors contain the bZIP structural motif and mediate their transcriptional activities via heterodimerization with ATF and AP-1 family members. Quenching of CREB-associated proteins by a dominant-negative CREB (KCREB) that is mutated within its DNA-binding domain decreases radiation resistance of human melanoma cells. The purpose of this study was to determine the role of CREB in tumor growth and metastasis of human melanoma using KCREB. Highly metastatic MeWo human melanoma cells were transfected with the KCREB expression vector and subsequently analysed for changes in their tumorigenic and metastatic potential. Expression of KCREB in MeWo human cells decreased their tumorigenic and metastatic potential in nude mice compared with parental and control transfected cells. The KCREB-transfected cells displayed downregulation of 72 kDa collagenase type IV (MMP-2) mRNA expression and activity and decreased invasiveness through Matrigel-coated filters. Moreover, transcriptional activities mediated by the CAT gene driven by the MMP-2 promoter were decreased by 14-45-fold in KCREB-transfected cells. In addition, the cell-surface adhesion molecule MCAM/MUC18 that is involved in metastasis of human melanoma was downregulated in the KCREB-transfected cells. These data indicate that, through their transcriptional activities, CREB and its associated proteins play an important role in the acquisition of the metastatic phenotype of human melanoma cells.

Direct correlation between MUC18 expression and metastatic potential of human melanoma cells

The expression of the glycoprotein MUC18 in melanoma biopsies has previously been shown to increase with increasing tumour thickness, and thus to correlate with the probability of metastasis development. We have examined the expression of this molecule by nine human melanoma cell lines with known metastatic ability (both spontaneous and experimental) in nude mice. Examination of the expression of both the MUC18 mRNA and of the glycoprotein on the cell surface revealed a statistically significant correlation (P = 0.040) between its expression and the ability to form metastases in vivo. Although MUC18 shows sequence similarity to neural cell adhesion molecules, no correlation was observed between the site of origin of the metastatic lesions (brain, lymph node) and MUC18 expression.

Oxidative stress, redox homeostasis and cellular stress response in Ménière's disease: role of vitagenes

Ménière's disease (MD) is characterized by the triad of fluctuating hearing loss, episodic vertigo and tinnitus, and by endolymphatic hydrops found on post-mortem examination. Increasing evidence suggests that oxidative stress is involved in the development of endolymphatic hydrops and that cellular damage and apoptotic cell death might contribute to the sensorineural hearing loss found in later stages of MD. While excess reactive oxygen species (ROS) are toxic, regulated ROS, however, play an important role in cellular signaling. The ability of a cell to counteract stressful conditions, known as cellular stress response, requires the activation of pro-survival pathways and the production of molecules with anti-oxidant, anti-apoptotic or pro-apoptotic activities. Among the cellular pathways conferring protection against oxidative stress, a key role is played by vitagenes, which include heat shock proteins (Hsps) as well as the thioredoxin/thioredoxin reductase system. In this study we tested the hypothesis that in MD patients measurable increases in markers of cellular stress response and oxidative stress in peripheral blood are present. This study also explores the hypothesis that changes in the redox status of glutathione, the major endogenous antioxidant, associated with abnormal expression and activity of carbonic anhydrase can contribute to increase oxidative stress and to disruption of systemic redox homeostasis which can be associated to possible alterations on vulnerable neurons such as spiral ganglion neurons and consequent cellular degeneration. We therefore evaluated systemic oxidative stress and cellular stress response in patients suffering from Meniere's disease (MD) and in age-matched healthy subjects. Systemic oxidative stress was estimated by measuring protein oxidation, such as protein carbonyls (PC) and 4-hydroxynonenal (HNE) in lymphocytes of MD patients, as well as ultraweak luminescence (UCL) as end-stable products of lipid oxidation in MD plasma and lymphocytes, as compared to age-matched controls, whereas heat shock proteins Hsp70 and thioredoxin (Trx) expression were measured in lymphocytes to evaluate the systemic cellular stress response. Increased levels of PC (P < 0.01) and HNE (P < 0.05) have been found in lymphocytes from MD patients with respect to control group. This was paralleled by a significant induction of Hsp70, and a decreased expression of Trx (P < 0.01), whereas a significant decrease in both plasma and lymphocyte ratio reduced glutathione GSH) vs. oxidized glutathione (GSSG) (P < 0.05) were also observed. In conclusion, patients affected by MD are under condition of systemic oxidative stress and the induction of vitagenes Hsp70 is a maintained response in counteracting the intracellular pro-oxidant status generated by decreased content of GSH as well as expression of Trx. The search for novel and more potent inducers of vitagenes will facilitate the development of pharmacological strategies to increase the intrinsic capacity of vulnerable ganglion cells to maximize antidegenerative mechanisms, such as stress response and thus cytoprotection.

Redox modulation of cellular stress response and lipoxin A4 expression by Coriolus versicolor in rat brain: Relevance to Alzheimer's disease pathogenesis

Increasing evidence supports the notion that oxidative stress-driven neuroinflammation is an early pathological feature in neurodegenerative diseases. As a prominent intracellular redox system involved in neuroprotection, the vitagene system is emerging as a potential neurohormetic target for novel cytoprotective interventions. Vitagenes encode for cytoprotective heat shock proteins 70, heme oxygenase-1, thioredoxin and lipoxin A4. Emerging interest is now focusing on molecules capable of activating the vitagene system as novel therapeutic targets to minimize deleterious consequences associated with free radical-induced cell damage, such as in neurodegeneration. Mushroom-derived lipoxin A4 (LXA4) is an emerging endogenous eicosanoid able to promote resolution of inflammation, acting as an endogenous "braking signal" in the inflammatory process. Mushrooms have long been used in traditional medicine for thousands of years, being now increasingly recognized as rich source of polysaccharopeptides endowed with significant antitumor, antioxidant, antiviral, antibacterial and cytoprotective effects, thereby capable of stimulating host immune responses. Here we provide evidence of a neuroprotective action of the Coriolus mushroom when administered orally to rat. Expression of LXA4 was measured in different brain regions after oral administration of a Coriolus biomass preparation, given for 30 days. LXA4 up-regulation was associated with an increased content of redox sensitive proteins involved in cellular stress response, such as Hsp72, heme oxygenase-1 and thioredoxin. In the brain of rats receiving Coriolus, maximum induction of LXA4 was observed in cortex and hippocampus. Hsps induction was associated with no significant changes in IkBα, NFkB and COX-2 brain levels. Conceivably, activation of LXA4 signaling and modulation of stress-responsive vitagene proteins could serve as a potential therapeutic target for AD-related inflammation and neurodegenerative damage.

Neurological complications of celiac disease and autoimmune mechanisms: preliminary data of a prospective study in adult patients

Antibodies to gangliosides and Purkinje cells have been reported in patients with celiac disease (CD) with neuropathy and ataxia, respectively. Whether these antibodies are pathogenic is not clear. The response of neurological symptoms and antibody titers to a gluten-free diet is still controversial. The objective of our study was to assess whether neurological manifestations in CD patients correlate with antibody titers and a gluten-free diet.Thirty-five CD patients (9 males, 26 females, mean age 37.1 +/- 12.6 yrs) were followed prospectively. At initial evaluation, 23 were on a gluten-free diet, 12 were not. At recruitment and during follow-up, patients underwent neurological and electrophysiological evaluation. IgG, IgM, and IgA anti-ganglioside antibodies were assayed by ELISA; anti-neuronal antibodies were assessed by immunohistochemistry and Western blot. Four patients, all males, had electrophysiological evidence of neuropathy; three had been on a gluten-free diet for several months, and one was newly diagnosed. One had reduced tendon reflexes; another complained of distal paresthesias. With regard to anti-ganglioside antibodies, three patients had a moderate increase in antibodies without symptoms or signs of neuropathy. No patients had ataxia or cerebellar dysfunction, although in four patients reactivity to neuronal antigens was found. In 17 patients, an electrophysiological follow-up (mean duration of follow-up, 9 months) showed no changes. In conclusion, the preliminary results of this prospective study indicate that neuropathy, usually subclinical, may accompany CD. Antibody titers do not seem to correlate with neurological symptoms/signs or diet. Ongoing follow-up will help confirm these data and clarify the role, if any, of antibodies in neurological involvement in CD.

Pulmonary alveolar macrophages in patients with sarcoidosis and hypersensitivity pneumonitis: characterization by monoclonal antibodies

Using a panel of monoclonal antibodies (MoAbs), the frequency of cells bearing Class I and Class II major histocompatibility complex (MHC) determinants, transferrin receptor (TR) sites, and interleukin-2 receptors (IL-2R) has been evaluated on pulmonary alveolar macrophages (PAM) recovered from the bronchoalveolar lavage (BAL) fluid of 21 patients with pulmonary sarcoidosis (including 11 cases with active sarcoidosis and 10 cases with inactive disease), 8 patients with hypersensitivity pneumonitis (HP), and 6 normal non-smoking volunteers. When the frequency of Class II DR-positive cells was considered, 64.3% of control PAM expressed HLA-DR products. No statistically significant differences were observed between controls and sarcoid patients, while HP patients showed an enhanced proportion of DR+ PAM with respect to normal PAM (P less than 0.05). On the contrary, the frequency of PAM expressing HLA-DQ molecules was higher in both active sarcoidosis and HP patients with respect to patients with inactive sarcoidosis and normal subjects (P less than 0.001). A statistically significant increase in Class I antigen-positive PAM has been demonstrated in HP patients as compared to controls (P less than 0.05). Active sarcoid patients showed a higher number of PAM-bearing TR sites than controls and other groups of patients considered (P less than 0.001). An increase in the percentage of IL-2R-positive PAM has been demonstrated in active sarcoidosis (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Dementia, delusions and seizures: storage disease or genetic AD?

We describe a case of a young patient suffering from a rapidly progressive cognitive decline, associated with delusions, myoclonus and seizures and with no family history for dementia. Clinical features, along with skin biopsy findings were overlapping storage disease; the genetic analysis, however, demonstrated a de novo presenilin 1 mutation. The present report suggests the usefulness of genetic determinations in early-onset cases of dementia, even without an autosomal dominant trait of inheritance; for these cases and their relatives an extensive genetic counselling should be recommended.

Phenotypical and functional analysis of natural killer cells in sarcoidosis

The frequency of cells reactive with natural killer (NK)-related monoclonal antibodies (MoAbs) HNK-1, NKP-15, B73.1, VEP-13, Ab8.28 has been evaluated in the peripheral blood and bronchoalveolar lavage (BAL) fluid of 39 patients with pulmonary sarcoidosis (including 19 cases with active sarcoidosis and 20 cases with inactive disease). This phenotypic analysis was carried out together with the NK in vitro functional evaluation of cell populations from peripheral blood and BAL fluid. In addition, inhibition studies were performed in order to evaluate the ability of alveolar macrophages (M phi) to modulate NK activity. Data from peripheral blood showed an increased number of mononuclear cells bearing HNK-1, NKP-15, Ab8.28, VEP-13, and B73.1 determinants in patients with active sarcoidosis with respect to patients with inactive disease and controls. The majority of HNK-1-positive cells lacked both Leu2 and Leu3 antigens when investigated in a double marker system. A parallel increase in the in vitro cytotoxicity assay has been demonstrated. On the other hand, only a few mononuclear cells recovered from BAL fluid displayed a surface pattern of NK cells. This small population of HNK-1-positive cells expresses the HNK-1/Leu3 phenotype and does not exhibit NK activity. The alveolar M phi from sarcoid patients, as well as alveolar M phi from controls, have the property of inhibiting the NK activity of autologous peripheral blood lymphocytes. The lack of lung NK function in patients with active sarcoidosis may be related to the presence of immature forms of NK cells and/or to the release of soluble factors by alveolar macrophages.

Alexithymia, more than depression, influences glycaemic control of type 2 diabetic patients

PURPOSE

Psychiatric disorders could affect the patients' abilities to cope with diabetes. The objectives of this study were to assess the prevalence of depression and alexithymia among type 2 diabetic patients and investigate the possible correlations between these psychopathological phenomena and glycaemic control assessed through glycated hemoglobin (HbA1c).

METHODS

All the patients were evaluated through 20-item Toronto Alexithymia Scale (TAS-20), Hamilton rating scale for depression and Quality of Life Index. HbA1c values, diabetes duration, therapy and socio-demographic characteristics were recorded.

RESULTS

One hundred and twenty-eight patients (75 males and 53 female, mean age 64.7 ± 11.2 years) were enrolled. Alexithymic patients, compared to non-alexithymic ones, presented a significantly higher HbA1c (7.7 ± 1.5 vs. 7 ± 1.5, p = 0.016). No statistically significant difference was found when comparing the HbA1c of depressed versus non-depressed patients. Considering the raw values of HbA1c, the higher percentage was recorded among patients suffering from depression plus alexithymia (comorbidity group) followed by patients presenting alexithymia only, patients with neither depression nor alexithymia (control group) and, finally, those presenting depression only. The comorbidity group presented a significantly higher value of HbA1c (7.7 ± 1.2) than the control group (7 ± 1.6, p < 0.04) and the depressed patients (6.9 ± 1.3, p = 0.04). At the logistic regression, the HbA1c was found to be significantly associated only with alexithymia (TAS-20 total score) and insulin therapy.

CONCLUSIONS

Alexithymia more than depression influences glycaemic control. When evaluating a diabetic patient, a rapid screening for psychopathological alterations would guarantee a more accurate management. The treatment of any associated psychiatric disorders would improve the patients' quality of life.

Obsessive compulsive personality disorder in Progressive Supranuclear Palsy, Multiple System Atrophy and Essential Tremor

INTRODUCTION

aim of the study was to evaluate the presence of the Obsessive Compulsive Personality Disorder (OCPeD) in Multiple System Atrophy (MSA), Progressive Supranuclear Palsy (PSP) and Essential Tremor (ET) and in a group of healthy subjects.

METHODS

patients affected by MSA, PSP and ET diagnosed according to currently accepted diagnostic criteria and a group of healthy controls were enrolled in the study. Patients with cognitive impairment were excluded from the study. The Structured Clinical Interview for Personality Disorders-II (SCID-II) has been performed to evaluate the presence of personality disorders (PeDs). The diagnosis of OCPeD was confirmed by a psychiatric interview.

RESULTS

fifteen MSA patients (8 men and 7 women; aged 62.9 ± 7.6 years), 14 PSP patients (8 men and 6 women; aged 69.8 ± 4.4 years), 16 ET patients (10 men and 6 women; aged 70.4 ± 6.4 years) and 20 healthy subjects (10 men and 10 women; aged 65.5 ± 6.0 years) were enrolled. OCPeD was recorded in 5 (35.7%) PSP patients, 2 (13.3%) MSA patients, 2 (12.5%) ET patient and 2 (10%) controls.

CONCLUSION

a low frequency of OCPeD, close to those recorded in healthy subjects, was recorded in both MSA and ET patients. Conversely an higher frequency of OCPeD, similar to PD was found among PSP patients, supporting the possibility of an impairment of common basal ganglia network possibly involving the orbito-frontal circuits.

Effects of lead and manganese on the release of lysosomal enzymes in vitro and in vivo

In this study we evaluated the effects of two heavy metals, lead and manganese, on the release of some glycohydrolases of lysosomal origin. N-acetyl-beta-D-glucosaminidase and its major isoenzymes, beta-D-glucuronidase and alpha-D-galactosidase. We have studied release of these enzymes in vitro from peripheral mitogen-activated lymphocytes from healthy subjects after addition of Pb or Mn to the medium and their plasma levels in individuals exposed at work to Pb (31 subjects) or to manganese (36 subjects), versus matched controls. We also determined the plasma levels in a general population (417 subjects). The enzymatic activities were assayed fluorimetrically with 4-methylumbelliferyl-glycosides as substrates. Particular attention was given to some technical aspects: enzymatic activity was preserved by addition of ethylene glycol and stable liquid material was employed for calibration purposes. N-acetyl-beta-D-glucosaminidase isoenzymes were separated by a routine chromatofocusing procedure on PBE 94. The addition of both metals to lymphocytes inhibits lysosomal enzyme release. These data were supported by the plasma levels for the exposed subjects, in which enzyme levels were significantly decreased after either type of exposure. In the general population of subjects not professionally exposed, the effect of lead appears to be masked by concomitant effects of alcohol consumption. Undoubtedly, some heavy metals can alter distribution of glycohydrolases of lysosomal origin between the intra- and extracellular environment, probably interfering with membrane mechanisms. Lysosomal enzymes seem to behave as sensitive biomarkers for early subclinical changes that might later lead to clinical disease.

Rearrangement for the T-cell receptor gene and co-expression of immature T-cell markers and natural killer cell phenotype, in a patient with acute lymphoblastic leukaemia

We describe a patient with acute lymphoblastic leukaemia whose blasts co-expressed immature T-cell markers and nearly the entire phenotypic repertoire of NK cells. The T-cell nature of the proliferating blasts was proven by the demonstration of the rearrangement for the beta-chain of the T-cell antigen receptor. Although an abnormal phenotypic expression related to the neoplastic proliferation cannot be formally excluded, it is possible that the cells in this patient may represent the clonal expansion of a normal subpopulation of T-cell lineage NK-related cells frozen at an early stage of differentiation. These features provide arguments for discussing the controversial issue of the ontogeny of NK cells and their relationship to the T-cell lineage.

A COMPARISON BETWEEN PREDICTION POWER OF ARTIFICIAL NEURAL NETWORKS AND MULTIVARIATE ANALYSIS IN ROAD SAFETY MANAGEMENT

This paper presents a methodology for the management of road safety on two-lane highways. The methodology is based on an experimental investigation carried out on a stretch of road located in southern Italy (the two-lane highway SS106). The study analyses accidents occurring between 2000 and 2005 and the data concerning the accidents that were acquired from police reports. The geometric data were acquired from the official cartography, while the traffic and environmental data were provided by the regional agency for roadway management. The data, organized and stored in a specific designed Geographic Information System (GIS), were processed using a series of statistical procedures, in particular, the results took out the following two models: Model 1 was produced by MultiVariate Analysis (MVA) and the Model 2 was obtained using the Artificial Neural Network (ANN) technique. Comparing the two models, it emerged that Model 2 is better than Model 1 because the total sum of the residual is lower. However, Model 1 is more efficient in estimating the more dangerous black spots.

Sea urchin harvest inside marine protected areas: an opportunity to investigate the effects of exploitation where trophic upgrading is achieved

Background

Marine protected areas (MPAs) usually have both positive effects of protection for the fisheries' target species and indirect negative effects for sea urchins. Moreover, often in MPAs sea urchin human harvest is restricted, but allowed. This study is aimed at estimating the effect of human harvest of the sea urchin Paracentrotus lividus within MPAs, where fish exploitation is restricted and its density is already controlled by a higher natural predation risk. The prediction we formulated was that the lowest densities of commercial sea urchins would be found where human harvest is allowed and where the harvest is restricted, compared to where the harvest is forbidden.

Methods

At this aim, a collaborative database gained across five MPAs in Sardinia (Western Mediterranean, Italy) and areas outside was gathered collecting sea urchin abundance and size data in a total of 106 sites at different degrees of sea urchin exploitation: no, restricted and unrestricted harvest sites (NH, RH and UH, respectively). Furthermore, as estimates made in past monitoring efforts (since 2005) were available for 75 of the sampled sites, for each of the different levels of exploitation, the rate of variation in the total sea urchin density was also estimated.

Results

Results have highlighted that the lowest sea urchin total and commercial density was found in RH sites, likely for the cumulative effects of human harvest and natural predation. The overall rate of change in sea urchin density over time indicates that only NH conditions promoted the increase of sea urchin abundance and that current local management of the MPAs has driven towards an important regression of populations, by allowing the harvest. Overall, results suggest that complex mechanisms, including synergistic effects between natural biotic interactions and human pressures, may occur on sea urchin populations and the assessment of MPA effects on P. lividus populations would be crucial to guide management decisions on regulating harvest permits. Overall, the need to ban sea urchin harvest in the MPAs to avoid extreme reductions is encouraged, as inside the MPAs sea urchin populations are likely under natural predation pressures for the trophic upgrading.