BCR expression is decreased in meningiomas showing loss of heterozygosity of 22q within a new minimal deletion region

Neurofibromin 2 (NF2), located on chromosome arm 22q, has been established as a tumor suppressor gene involved in meningioma pathogenesis. In our study, we investigated 149 meningiomas to determine whether there are additional tumor suppressor genes localized on chromosome 22q, apart from NF2, that might be involved in meningioma pathogenesis. The LOH analysis on chromosome 22q identified two regions of deletion: the first one, which is limited to the NF2 gene locus, and the second one, which is outside this location. The new minimal deletion region (MDR) included the following genes: BCR (breakpoint cluster region), RAB36 (a member of RAS oncogene family), GNAZ [guanine nucleotide binding protein (G protein), alpha-z polypeptide], and RTDR1 (rhabdoid tumor deletion region gene 1). The expression levels of all these genes, including NF2, were subsequently analyzed by quantitative real-time polymerase chain reaction. We observed a significantly lowered expression level of NF2 in meningiomas with 22q loss of heterozygosity (LOH) within NF2 region compared to the one in meningiomas with 22q retention of heterozygosity (ROH, P<0.05). Similarly, BCR showed a significantly lowered expression in meningiomas with 22q LOH within the new MDR compared to cases with 22q ROH (P<0.05). Our data, together with the already published information considering BCR function suggest that BCR can be considered as a candidate tumor suppressor gene localized on chromosome 22q which may be involved in meningioma pathogenesis.

Amifostine can differentially modulate DNA double-strand breaks and apoptosis induced by idarubicin in normal and cancer cells

We have previously shown that amifostine differentially modulated the DNA-damaging action of idarubicin in normal and cancer cells and that the presence of p53 protein and oncogenic tyrosine kinases might play a role in this diversity.

AIM

To investigate further this effect we have studied the influence of amifostine on idarubicin-induced DNA double-strand breaks (DSBs) and apoptosis.

METHODS

We employed pulse-field gel electrophoresis () for the detection of DSBs and assessment of their repair in human normal lymphocytes and chronic myelogenous leukaemia K562 cells lacking p53 activity and expressing the BCR/ABL tyrosine kinase. Apoptosis was evaluated by caspase-3 activity assay assisted by the alkaline comet assay and DAPI staining.

RESULTS

Idarubicin induced DSBs in a dose-independent manner in normal and cancer cells. Both types of the cells did not repair these lesions in 120 min and amifostine differentially modulated their level - decreased it in the lymphocytes and increased in K562 cells. In contrast to control cells, amifostine potentated apoptotic DNA fragmentation, chromatin condensation and the activity of caspase-3 in leukaemia cells.

CONCLUSION

Amifostine can differentially modulate DSBs and apoptosis induced by idarubicin in normal and cancer cells. It can protect normal cells against drug-induced DNA damage and it can potentate the action of the drug in leukaemic cells. Further studies on link between amifostine-induced modulation of DSBs and apoptosis of cancer cells will bring a deeper insight into molecular mechanism of amifostine action.

Augeninnendruckmessungen im Tages- und Nachtverlauf bei Glaukompatienten und Normalprobanden mittels Goldmann- und Perkins-Applanationstonometrie

OBJECTIVE

Our aim was to evaluate intraocular pressure (IOP) levels in primary open angle glaucoma (POAG) patients and healthy controls during both the day and night while measuring in an upright as well as in a supine position.

METHODS

In a prospective clinical trial, 30 glaucoma patients on topical treatment and 50 healthy controls received IOP measurements every 4 h for a 24 h period starting at 8 am. Additionally, blood pressure and heart rate were measured and perfusion pressures were calculated. At 12 am IOP was initially measured in a sitting position and then, after 20 min, in a supine position. At midnight this was carried out conversely. At 4 am IOP was measured in a supine position; all other measurements were performed in a sitting position. Measurements in the sitting position were performed by Goldmann and Perkins tonometry and in a supine position by Perkins tonometry.

RESULTS

IOP was 1 mmHg lower in Perkins tonometry measurements compared to Goldmann tonometry. There was no difference between the two patient groups. In a supine position, IOP measured by Perkins tonometry was higher than in an upright position. At 12 am the difference was 1.8 mmHg+/-2.7 mmHg (p=0.001) in healthy subjects and 1.3+/-2.7 mmHg (p=0.013) in the POAG patients. At 12 pm the increase of IOP in the supine position was even more pronounced with 2.4+/-3.4 mmHg in healthy subjects and 5.6+/-3.2 mmHg in the POAG patients (p=0.001). The blood pressure and the perfusion pressure were lowest during night measurements.

CONCLUSIONS

During diurnal IOP measurements in an upright position there were no statistically significant differences in IOP changes between groups. However, in a supine position IOP was significantly higher than in a sitting position and increased more in the glaucoma patients than in healthy controls. This observation might be due to a faulty regulation of the fluid shift in glaucoma patients and could cause progression of glaucomatous damage.

Molecular analysis of chromosome 1, 10 and 19 abnormalities in human oligodendroglial tumors: relationship between frequency of LOH grade, age and gender

BACKGROUND

Loss of heterozygosity (LOH) on 1p and 19q is observed in most oligodendroglial tumors. LOH on 10q appears to be less common in these tumors as compared to other gliomas.

PATIENTS AND METHODS

We reviewed 14 patients with oligodendroglial tumors (10 low-grade and 4 anaplastic oligodendroglioma) to evaluate the frequency of LOH on 1p, 10q and 19q and correlate it with tumor grade and patients' age and gender; 5 loci on 1p and 5 on 19q as well as 4 on 10q were analyzed for LOH using PCR techniques.

RESULTS

LOH on 1p together with 19q was detected in 6 tumors, 1 tumor showed deletion of 19q accompanied with deletion on 10q. Deletion on 1p was associated with deletion of 19q (p < 0.005) and mutual associations among deletions at loci on 19q (p < 0.05) were found. Patients with LOH on 1p were younger on average than patients with retained heterozygosity (p = 0.05). Grade II oligodendrogliomas predominated among younger patients (p < 0.01) while grade III oligodendrogliomas predominated among women (p < 0.005). No association between LOH on 1p nor 19q and tumor grade or patients' gender was found.

CONCLUSION

Our study provides several clinically interesting findings and further supports the hypothesis of chromosome 1p and 19q involvement in the oligodendroglial cancerogenesis.

GADD45A and EPB41 as tumor suppressor genes in meningioma pathogenesis

Deletions of 1p occur in approximately 30% of meningiomas. Based on loss of heterozygosity (LOH) analysis, two regions on 1p have been suspected to be carriers of tumor suppressor genes. We chose the GADD45A and EPB41 genes as tumor suppressor candidates based on their function and chromosomal localization. We analyzed 19 cases of meningioma with LOH of 1p by means of sequencing of the GADD45A gene and Western blotting of the GADD45a protein. Twenty cases of meningioma without 1p LOH were also analyzed by Western blotting to find out if changes of the GADD45a protein expression occurred. Nineteen samples with 1p LOH (12 grade I; 7 grade II, WHO classification) and 20 samples without 1p LOH (18 grade I; 2 grade II) were also analyzed by means of real-time polymerase chain reaction to find abnormalities in EPB41 mRNA levels in meningioma. LOH analysis was performed using seven microsatellite markers: D1S508 (1p36.2), D1S199 (1p36.1) D1S2734 (1p36.1), D1S2720 (1p34), D1S197 (1p32), D1S162 (1p32), D1S429 (1p11). LOH analysis confirmed previously described localization of putative tumor suppressor genes on 1p and involvement in meningioma pathogenesis (1p36 and 1p32). The open reading frame of GADD45A and intron splicing sites showed neither mutations nor polymorphisms. GADD45a protein molecular weight and expression level were unaltered in meningiomas with and without 1p LOH. We conclude that the GADD45A gene is not involved in meningioma tumorigenesis. EPB41 gene expression was unchanged in all analyzed meningiomas. This suggests that involvement of the EPB41 gene (4.1R protein) in meningioma pathogenesis should be reconsidered.

Genotoxicity of streptozotocin in normal and cancer cells and its modulation by free radical scavengers

Streptozotocin (STZ) is an antibiotic which can be used to induce diabetes in experimental animals in order to have an insight into pathogenesis of this disease. To use STZ as a diabetogenic substance, its molecular mode of action should be elucidated. Using the alkaline comet assay, we showed that STZ at concentrations in the range 0.01-100 micromol/L induced DNA damage in normal human lymphocytes and HeLa cancer cells in a dose-dependent manner. Lymphocytes were able to remove damage to their DNA within a 30-min repair incubation, whereas HeLa cells completed the repair in 60 min. Vitamins C and E at 10 and 50 micromol/L diminished the extent of DNA damage induced by 50 micromol/L STZ. Pretreatment of the lymphocytes with the nitrone spin trap, alpha-(4-pyridil-1-oxide)-N-tert-butylnitrone (POBN) or ebselen, which mimics glutathione peroxidase, or pyrrolidine dithiocarbamate (PDTC) reduced the extent of DNA damage evoked by STZ. The cells exposed to STZ and treated with endonuclease III (Endo III), formamidopyrimidine-DNA glycosylase (Fpg) and 3-methyladenine-DNA glycosylase II (AlkA), the enzymes recognizing oxidized and alkylated bases, displayed greater extent of DNA damage than those not treated with these enzymes. These results suggest that free radicals may be involved in the formation of DNA lesions induced by streptozotocin. The drug can also alkylate DNA bases. This broad range of DNA damage induced by STZ indicates that the drug may seriously affect genomic stability in normal and pathological cells.

Reduced isolation-induced aggressiveness in mice following NAALADase inhibition

RATIONALE

Long-term individual housing increases aggressive behavior in mice, a condition termed isolation-induced aggression; this aggressiveness is reduced by some antidepressants and anxiolytics. NMDA antagonists also inhibit isolation-induced aggression in mice. The enzyme N-acetylated-alpha-linked acidic dipeptidase (NAALADase) hydrolyzes the neurotransmitter N-acetylaspartylglutamate (NAAG) to form glutamate and N-acetylaspartate; NAAG acts as a partial NMDA agonist as well as a full agonist at the presynaptic metabotropic glutamate receptor 3 (mGluR3), where it acts to reduce glutamate release.

OBJECTIVE

We postulated that NAALADase inhibition would reduce isolation-induced aggression in mice.

METHODS

We tested whether acute exposure to the NAALADase inhibitor 2-[[hydroxy[2,3,4,5,6-pentafluorophenyl)methyl]phosphinyl]methyl] pentanedioic acid (GPI-5232), administered 30 min prior to a social interaction test, would inhibit aggressive behavior in SJL mice that had been individually housed long term.

RESULTS

Administration of GPI-5232 (30 mg/kg, IP) inhibited initiation of aggressive behavior, indicated by greater latencies to display tail-rattling, attack and biting, and by fewer mice initiating aggressive behavior, compared to mice that received vehicle. In addition, GPI-5232 treated mice had fewer tail-rattling responses to a non-aggressive conspecific.

CONCLUSIONS

The effectiveness of GPI-5232 in this animal model suggests that NAALADase inhibition may be a novel therapeutic approach to reduce or inhibit heightened aggressiveness, and possibly to treat aggressive behavior associated with psychiatric disorders.

Influence of periodontal disease on Th1/Th2-type cytokines in saliva of HIV-positive individuals

Cytokines present during immune responses have a tremendous influence on resistance/susceptibility to oral diseases including periodontal disease and oral opportunistic infections in the immunocompromised individual, as seen by altered Th cytokines in saliva with human immunodeficiency virus (HIV) disease progression and oropharyngeal candidiasis. This study was designed to evaluate whether the presence of severe periodontal disease has any influence on Th cytokines in saliva of HIV-positive persons. For this, saliva from a cohort of HIV-positive persons with mild or severe periodontitis was evaluated for Th cytokines. A dominant Th2-type cytokine profile in saliva was validated in HIV-positive subjects with considerable immune suppression, irrespective of periodontal disease status. However, no significant differences in concentrations of Th1- or Th2-type cytokines in saliva were observed when stratified by periodontal status. Thus, the lack of salivary influences by periodontitis eliminates periodontal disease as a variable in interpretations regarding correlates of local cytokines during oral manifestations of HIV.

Design and pharmacological activity of phosphinic acid based NAALADase inhibitors

A novel series of phosphinic acid based inhibitors of the neuropeptidase NAALADase are described in this work. This series of compounds is the most potent series of inhibitors of the enzyme described to date. In addition, we have shown that these compounds are protective in animal models of neurodegeneration. Compound 34 significantly prevented neurodegeneration in a middle cerebral artery occlusion model of cerebral ischemia. In addition, in the chronic constrictive model of neuropathic pain, compound 34 significantly attenuated the hypersensitivity observed with saline-treated animals. These data suggest that NAALADase inhibition may provide a new approach for the treatment of both neurodegenerative disorders and peripheral neuropathies.

Resistance of T-cell receptor delta-chain-deficient mice to experimental Candida albicans vaginitis

Conditions consistent with tolerance or immunoregulation have been observed in experimental Candida albicans vaginal infections. The present study investigated the role of gamma/delta T cells in experimental vaginal candidiasis. Results showed that T-cell receptor delta-chain-knockout mice had significantly less vaginal fungal burden when compared to wild-type mice, suggesting an immunoregulatory role for gamma/delta T cells in Candida vaginitis.

In vivo virulence of Candida albicans isolates causing mucosal infections in people infected with the human immunodeficiency virus

Mucosal candidiasis is common in human immunodeficiency virus (HIV) infection. Susceptibility to such infections may be attributed to reduced host defense mechanisms and/or virulence of the organism. In the present study, we compared the virulence of mucosal Candida albicans isolates from HIV-infected people, with and without fluconazole-refractory infection, in established murine models of systemic and vaginal candidiasis. Compared with the mortality rate ( approximately 70%) after intravenous challenge with 2 virulent reference isolates, challenge with most clinical isolates (66%-77%) resulted in prolonged survival. In contrast, fungal burden induced by intravaginal challenge of nearly all (97%) isolates was similar to that of the virulent controls. There were no differences in in vitro growth rates for any of the isolates, and there was no association between reduced mortality and clinical failure to fluconazole, in vitro antifungal susceptibility, site of infection, or other host factors. These results suggest that virulence of C. albicans is tissue specific and is not a factor in the development of fluconazole-refractory infections in advanced HIV disease.

Blockade of NAALADase: a novel neuroprotective strategy based on limiting glutamate and elevating NAAG

Excessive glutamate receptor activation is thought to be involved in the neuronal injury caused by stroke. Based on the hypothesis that N-acetyl-aspartyl-glutamate (NAAG) is a modulatory neurotransmitter or storage form of glutamate, we have pursued a novel strategy of therapeutic intervention, blockade of N-acetylated alpha-linked acidic dipeptidase (NAALADase), the enzyme that hydrolyzes NAAG to liberate glutamate. Using the suture model of transient middle cerebral artery occlusion (MCAO) in rats, the prototype NAALADase inhibitor 2-(phosphonomethyl)pentanedioic acid (2-PMPA) dramatically reduced extracellular glutamate accumulation measured by microdialysis both during a 2-hour occlusion and during reperfusion, consistent with an effect on glutamate supply. During reperfusion, the decrease in glutamate was accompanied by an equimolar, reciprocal rise in extracellular NAAG. NAALADase inhibition may prove to be a well tolerated therapy for cerebral ischemia. In addition, NAALADase inhibitors should prove to be important tools in understanding the physiological role of NAAG in the brain.