17q21.31 duplication causes prominent tau-related dementia with increased MAPT expression.

To assess the role of rare copy number variations in Alzheimer's disease (AD), we conducted a case-control study using whole-exome sequencing data from 522 early-onset cases and 584 controls. The most recurrent rearrangement was a 17q21.31 microduplication, overlapping the CRHR1, MAPT, STH and KANSL1 genes that was found in four cases, including one de novo rearrangement, and was absent in controls. The increased MAPT gene dosage led to a 1.6-1.9-fold expression of the MAPT messenger RNA. Clinical signs, neuroimaging and cerebrospinal fluid biomarker profiles were consistent with an AD diagnosis in MAPT duplication carriers. However, amyloid positon emission tomography (PET) imaging, performed in three patients, was negative. Analysis of an additional case with neuropathological examination confirmed that the MAPT duplication causes a complex tauopathy, including prominent neurofibrillary tangle pathology in the medial temporal lobe without amyloid-ß deposits. 17q21.31 duplication is the genetic basis of a novel entity marked by prominent tauopathy, leading to early-onset dementia with an AD clinical phenotype. This entity could account for a proportion of probable AD cases with negative amyloid PET imaging recently identified in large clinical series.

Extracellular vesicle-mediated suicide mRNA/protein delivery inhibits glioblastoma tumor growth in vivo.

Extracellular vesicles (EVs) are considered as important mediators of intercellular communication, which carry a diverse repertoire of genetic information between cells. This feature of EVs can be used and improved to advance their therapeutic potential. We have previously shown that genetically engineered EVs carrying the suicide gene mRNA and protein-cytosine deaminase (CD) fused to uracil phosphoribosyltransferase (UPRT)-inhibited schwannoma tumor growth in vivo. To further examine whether this approach can be applied to other cancer types, we established a subcutaneous xenograft glioblastoma tumor model in mice, as glioblastoma represents the most common primary brain tumor, which is highly aggressive compared with the original schwannoma tumor model. U87-MG glioblastoma cells were implanted into the flanks of nude SCID mice, and the animals were intratumorally injected with the EVs isolated from the cells expressing EGFP or CD-UPRT. After the intraperitoneal administration of the prodrug 5-fluorocytosine, the tumor growth was assessed by regular caliper measurements. Our data revealed that the treatment with the CD-UPRT-enriched EVs significantly reduced the tumor growth in mice. Taken together, our findings suggest that EVs uploaded with therapeutic CD-UPRT mRNA/protein may be a useful tool for glioblastoma treatment.

The c.65-2A>G splice site mutation is associated with a mild phenotype in Danon disease due to the transcription of normal LAMP2 mRNA.

Danon disease (DD) is a rare X-linked multisystem disorder caused by mutations of the LAMP2 gene and characterized by intellectual disability, skeletal myopathy and cardiomyopathy. The survival time is severely reduced. Contrasting with the usual disease course, we report on a family with an exceptionally mild phenotype of DD despite having two potentially damaging LAMP2 mutations. Using RNA-Seq analysis, we showed that a c.65-2A>G splice site mutation results in the tissue-specific production of four different transcripts including the full-length mRNA in muscle tissue but not in leukocytes. We confirmed our results by immunohistochemistry and immunoblotting, showing the detection of LAMP2 protein only in muscle. The second mutation (c.586A>T, p.T196S) has been reported before to have an uncertain clinical significance. In our patients, however, neither of the two mutations seem to have a high enough functional impact to cause a severe phenotype. Overall, our study reveals that alternative splicing is a potential mechanism in DD with underlying splice site mutations of the LAMP2 gene in order to rescue the full-length mRNA. Moreover, our report of a mild phenotype complements the DD spectrum, which is of great importance for a rare disease suspected to be underdiagnosed.

miR-200a-mediated suppression of non-muscle heavy chain IIb inhibits meningioma cell migration and tumor growth in vivo.

miR-200a has been implicated in the pathogenesis of meningiomas, one of the most common central nervous system tumors in humans. To identify how miR-200a contributes to meningioma pathogenesis at the molecular level, we used a comparative protein profiling approach using Gel-nanoLC-MS/MS and identified approximately 130 dysregulated proteins in miR-200a-overexpressing meningioma cells. Following the bioinformatic analysis to identify potential genes targeted by miR-200a, we focused on the non-muscle heavy chain IIb (NMHCIIb), and showed that miR-200a directly targeted NMHCIIb. Considering the key roles of NMHCIIb in cell division and cell migration, we aimed to identify whether miR-200a regulated these processes through NMHCIIb. We found that NMHCIIb overexpression partially rescued miR-200a-mediated inhibition of cell migration, as well as cell growth in vitro and in vivo. Moreover, siRNA-mediated silencing of NMHCIIb expression resulted in a similar migration phenotype in these cells and inhibited meningioma tumor growth in mice. Taken together, these results suggest that NMHCIIb might serve as a novel therapeutic target in meningiomas.

Depletion of minichromosome maintenance protein 7 inhibits glioblastoma multiforme tumor growth in vivo.

Minichromosome maintenance (MCM) proteins are key elements that function as a part of the pre-replication complex to initiate DNA replication in eukaryotes. Consistent with their roles in initiating DNA replication, overexpression of MCM family members has been observed in several malignancies. Through bioinformatic analysis of The Cancer Genome Atlas's data on glioblastoma multiforme (GBM), we found that the genomic region containing MCM7 gene was amplified in more than 80% of the present cases. To validate this finding and to identify the possible contribution of the remaining members of the MCM family to GBM progression, we used quantitative real-time PCR to analyze the gene expression profiles of all MCM family members in Grade IV (GBM) tissue samples and observed a significant upregulation in GBM samples compared with normal white matter tissues. In addition, we compared the observed gene expression profiles with those of Grade II and Grade III astrocytoma samples and determined that the observed upregulation was restricted and specific to Grade IV. MCM7 was the most upregulated gene in the gene set we analyzed, and therefore we wanted to identify the role of MCM7 in GBM progression. We determined that siRNA-mediated knockdown of MCM7 expression reduced GBM cell proliferation and also inhibited tumor growth in both xenograft and orthotopic mouse models of GBM. Taken together, our data suggest that MCM7 can be a potential prognostic marker and a novel therapeutic target in GBM therapy.

Unclassifiable tauopathy associated with an A152T variation in MAPT exon 7.

Mutations in the microtubule-associated tau (MAPT) gene are associated clinically with frontotemporal dementia with or without supranuclear palsy, corticobasal syndrome or parkinsonism. Here we present clinical, neuropathological, genetic and biochemical data on a patient with an A152T variation in exon 7 of MAPT. A 63-year-old man presented with memory disturbance and later speech disorder, followed by progressive dementia and terminally myoclonus together with periodic sharp waves in EEG. Duration of illness was 5 years. Similar neuropsychiatric symptoms were reported in the patient's father. Neuropathological evaluation revealed neuronal loss mainly in the frontal and temporal cortices and substantia nigra. Abundant phospho-tau immunoreactive thread-like structures and diffuse staining of neuronal cytoplasm predominated in the frontal and temporal cortex, and hippocampus. There was a lack of astrocytic plaques and tufted astrocytes, and only a moderate number of oligodendroglial coiled bodies were seen. Tau pathology was characterized by the 4R tau isoform; immunoblot revealed bands at 64 and 68 kDa, and ultrastructure of filaments was compatible with twisted ribbons. Pathogenic mutations have not been reported in exon 7. Our observation of an apparently familial disorder with a novel neuropathological phenotype suggests a possible pathogenic role of this MAPT gene variation, which might be different from mutations affecting the microtubule binding.

Alzheimer-type neuropathology in a 28 year old patient with iatrogenic Creutzfeldt-Jakob disease after dural grafting.

We report the case of a 28 year old man who had received a cadaverous dura mater graft after a traumatic open skull fracture with tearing of the dura at the age of 5 years. A clinical suspicion of Creutzfeldt-Jakob disease (CJD) was confirmed by a brain biopsy 5 months prior to death and by autopsy, thus warranting the diagnosis of iatrogenic CJD (iCJD) according to WHO criteria. Immunohistochemistry showed widespread cortical depositions of disease associated prion protein (PrP(sc)) in a synaptic pattern, and western blot analysis identified PrP(sc) of type 2A according to Parchi et al. Surprisingly, we found Alzheimer-type senile plaques and cerebral amyloid angiopathy in widespread areas of the brain. Plaque-type and vascular amyloid was immunohistochemically identified as deposits of beta-A4 peptide. CERAD criteria for diagnosis of definite Alzheimer's disease (AD) were met in the absence of neurofibrillar tangles or alpha-synuclein immunoreactive inclusions. There was no family history of AD, CJD, or any other neurological disease, and genetic analysis showed no disease specific mutations of the prion protein, presenilin 1 and 2, or amyloid precursor protein genes. This case represents (a) the iCJD case with the longest incubation time after dural grafting reported so far, (b) the youngest documented patient with concomitant CJD and Alzheimer-type neuropathology to date, (c) the first description of Alzheimer-type changes in iCJD, and (d) the second case of iCJD in Austria. Despite the young patient age, the Alzheimer-type changes may be an incidental finding, possibly related to the childhood trauma.

Increased incidence of genetic human prion disease in Hungary.

The authors performed analysis of the prion protein gene (PRNP) in 27 out of 109 confirmed prion disease patients between 1994 and 2004. E200K mutation was found in 17 cases. Another 10 patients, lacking PRNP analysis, showed positive family history. The mean annual incidence (0.27/million) and proportion (25.6%) of genetic prion disease is unusually high in Hungary and might be related to the migration of ancestors from the Slovakian focus.

Presence of D110 antigen expressing immunocompetent cells in glioblastoma associates with prolonged survival.

Monoclonal antibody D110 has recently been described as a novel marker of hypoxic tissue damage, reacting with a so far unknown antigen with preferential expression in the central nervous system. The aim of the study was to investigate D110 immunoreactivity in glioblastoma, its association with the expression of hypoxia-related proteins and its impact on patient outcome. A total of 114 consecutive adult patients who underwent first operation of primary glioblastoma were included in this study. We evaluated D110 immunoreactivity qualitatively and semi-quantitatively and correlated it with expression of hypoxia inducible factor 1 alpha (HIF-1alpha), expression of vascular endothelial growth factor (VEGF), and with patient survival using univariate and multivariate statistical analysis. We observed D110 immunolabelling in 85.1% of the cases. D110 immunoreactivity was detectable in infiltrating HLA-DR and CD68 expressing cells, most likely microglial cells or haematogenous cells of monocyte/macrophage lineage. In the peripheral lymphoreticular system, immunohistochemistry disclosed selective D110 labelling of Langerhans cells and of dendritic cells of the thymic medulla. Univariate statistical analysis revealed significantly longer survival of patients whose glioblastomas contained D110 immunoreactive infiltrating cells. There was no association between presence of D110 immunoreactive cells and expression of HIF-1alpha and VEGF. We conclude that D110 immunoreactivity in glioblastoma does not seem to be related to tissue hypoxia. D110 identifies immunocompetent cells, which positively influence survival of glioblastoma patients.

Myofibrillar (desmin-related) myopathy: clinico-pathological spectrum in 3 cases and review of the literature.

Myofibrillar or desmin-related myopathies encompass neuromuscular disorders with abnormal deposits of desmin and myofibrillar alterations. We report 3 unrelated patients presenting with proximal and distal myopathy, and, as a unique congenital syndrome, diffusely distributed myopathy, osteoporosis and myopia. Muscle biopsies shared cytoplasmic inclusions, rimmed vacuoles, and ragged-red-like fibers. Sarcoplasmic inclusions, either plaque-like or amorphous, strongly immunoreacted on dystrophin and variably for desmin, alphaB crystallin and ubiquitin. Cyclin-dependent kinases CDK1, CDK2 and CDK5 were overexpressed in affected fibers. Ultrastructurally, focal myofibrillar disruption was accompanied by tubulo-filamentous inclusions in one case and abundant glycogen and enlarged mitochondria displaying respiratory chain dysfunction at biochemistry in another case. Molecular analysis of the alphaB crystallin gene coding sequence and exons 4, 5 and 6 of the desmin gene did not reveal any mutation. The morphologic denominator of hyaline structures and areas of myofibrillar destruction occurs in heterogeneous conditions and may overlap with features of inclusion body myopathy and mitochondrial myopathy.

DNA topoisomerase IIalpha expression in optic pathway gliomas of childhood.

DNA topoisomerase IIalpha (Topo IIalpha) is linked to tumour cell growth and chemoresistance. We examined immunohistochemically Topo IIalpha expression levels in a series of 36 consecutive paediatric optic pathway glioma (OPG) patients. Topo IIalpha labelling index (LI) ranged from 0.0 to 11.6 and was significantly associated with patient age, with higher levels of Topo IIalpha in children < or = 3 years (P=0.031). Topo IIalpha expression did not correlate with patient survival. Topo IIalpha LI was not significantly increased in specimens of repeat surgery. Topo IIalpha LI closely correlated with MIB-1 LI (R=0.781, P<0.001). We conclude that Topo IIalpha expression correlates with tumour cell proliferation in paediatric OPGs. Assessment of cell proliferation, however, does not assist in refining prognostic predictions. Enhanced Topo IIalpha expression in children < or = 3.0 years suggests that Topo IIalpha-interfering anticancer compounds for adjuvant treatment of OPGs may be of particular benefit to young children.

Fibroblasts can express glial fibrillary acidic protein (GFAP) in vivo.

Neuropathologists use anti-glial fibrillary acidic protein (GFAP) antibodies as specific markers for glial cells, and neurobiologists use GFAP for targeting transgenes to glial cells. Since GFAP has also been detected in non-glial cells, we systematically analyzed GFAP expression in human and murine non-CNS tissues using a panel of anti-GFAP antibodies. In human tissues we confirm previously observed GFAP expression in Schwann cells, myoepithelial cells, and chondrocytes, and show for the first time GFAP expression in fibroblasts of epiglottic and auricular perichondrium, ligamentum flavum, and cardiac valves. In mice we show GFAP expression in Schwann cells, bone marrow stromal cells, chondrocytes, and in fibroblasts of dura mater, skull and spinal perichondrium, and periosteum, connective stroma of oral cavity, dental pulp, and cardiac valves. Anti-GFAP immunoblotting of human non-CNS tissues reveals protein bands with a molecular mass ranging between approximately 35 and approximately 42 kDa. In GFAP-v-src transgenic mice, whose oncogenic v-src transgene transforms GFAP expressing cells, non-CNS tumors originate from fibroblasts. We conclude that human and murine fibroblasts can express GFAP in vivo. The somatic distribution of GFAP expressing fibroblasts indicates origin from the neural crest. Development of non-CNS tumors from fibroblasts in GFAP-v-src mice functionally confirms GFAP expression in these cells.

Beta1-integrins partly mediate binding of ovarian cancer cells to peritoneal mesothelium in vitro.

Ovarian cancer cells frequently metastasize by implanting onto the peritoneal mesothelial surface of the abdominal cavity. Although the CD44 molecule expressed by ovarian cancer cells is known to partly mediate this process, the role of other adhesion proteins such as beta1-integrins has been previously difficult to demonstrate using the 4B4 anti-beta1 neutralizing antibody. In view of the widespread expression of beta1-integrins in ovarian cancer, however, we have further examined the potential role of this class of molecules in ovarian cancer cell implantation through the use of an alternative anti-beta1 neutralizing antibody, MAB13. We now report that MAB13 is capable of inhibiting the binding of three separate human ovarian cancer cell lines (36M2, CAOV-3, SKOV-3) to mesothelium (mean 37 +/- 4% inhibition, n = 21, P < 0.001). An additive inhibitory effect was observed when MAB13 was combined with anti-CD44 antibody (clone 515) (mean 63 +/- 3% inhibition, n = 19, P < 0.001), suggesting that binding occurs through two independent pathways involving both beta1-integrins and CD44. Because fibronectin is an extracellular matrix ligand recognized by many types of integrins and is abundantly expressed on mesothelial cells, the inhibitory effects of MAB13 and 4B4 on ovarian cancer cell binding to fibronectin were directly compared. MAB13 inhibited ovarian cancer cell binding to fibronectin to a significantly greater degree than did 4B4, suggesting that the discordant effects of these two antibodies on mesothelial adhesion may be partly related to their differential ability to neutralizing fibronectin-mediated binding. Studies using anti-alpha5 neutralizing antibody demonstrated that the alpha5beta1 fibronectin receptor contributes to approximately 50% of integrin-mediated binding of 36M2 and CAOV-3 cells (which express the alpha5 chain in 54 and 58% of cells, respectively). Since the RGD sequence of fibronectin is a known recognition site for many types of integrins, including alpha5beta1 and alphanubeta3, we performed binding in the continued presence of both anti-alpha5 and RGD peptide in order to exclude other types of fibronectin-integrin interactions. The addition of RGD peptides at concentrations known to be capable of blocking fibronectin binding resulted in no additional inhibitory effect over that observed with anti-alpha5 antibody alone, suggesting that alpha5beta1 was the major receptor responsible for fibronectin-mediated ovarian cancer binding to mesothelium. These data demonstrate that ovarian cancer cell binding to peritoneal mesothelium is mediated by several adhesion pathways and that simultaneous inhibition of both beta1-integrin and CD44 function may be necessary in order to significantly limit the intraabdominal spread of this tumor in vivo.

In vivo cytotoxicity of ovarian cancer cells through tumor-selective expression of the BAX gene.

The BAX proapoptotic protein is capable of inducing cell death either directly, through its effects on mitochondrial function, or indirectly, by lowering the apoptotic threshold in response to certain chemotherapy agents. In this study, we tested the hypothesis that selective expression of BAX in human ovarian cancer through adenoviral gene transfer might represent a novel approach to eradicating tumor cells in vivo. Two constructs were prepared using replication-deficient adenoviral vectors containing either the cDNA for beta-galactosidase (Ad.DF3.betaGAL) or hemagglutinin (HA)-tagged BAX (Ad.DF3.BAX) under the control of the DF3 promoter. The DF3 promoter was used to confer tumor-specific gene expression in view of its restricted pattern of expression in the majority of human ovarian cancers and its limited expression in normal peritoneal mesothelial cells. In vitro infection of up to seven different epithelial cancer cell lines with Ad.DF3.betaGAL or Ad.DF3.BAX resulted in expression of either beta-galactosidase activity or HA-BAX protein, respectively, which was highly correlated with DF3 levels. Furthermore, infection with Ad.DF3.BAX was capable of highly selective cytotoxicity of DF3-positive ovarian cancer clonogenic cells in vitro. The effect of i.p. administration of Ad.DF3.BAX was also assessed in nude mice inoculated with the DF3-positive 36M2 human ovarian cancer cell line. Expression of either beta-galactosidase activity (after Ad.DF3.betaGAL treatment) or HA-BAX transcripts (after Ad.DF3.BAX treatment) was restricted to tumor tissue in vivo. Importantly, administration of Ad.DF3.BAX on days 2 and 3 after tumor inoculation was capable of eradicating >99% of tumor implants. These results demonstrate the feasibility of tumor selective expression of a proapoptotic protein such as BAX through adenoviral gene transfer.

BAD partly reverses paclitaxel resistance in human ovarian cancer cells.

Although paclitaxel is an important chemotherapy agent for the treatment of patients with epithelial ovarian cancer, its utility is significantly limited by the frequent development of drug resistance. Recent evidence suggests that resistance to chemotherapy may be partly related to defects in the apoptotic pathway. In this study we have investigated whether enhancement of apoptotic pathway function through stable expression of the BAD protein is capable of sensitizing human epithelial ovarian cancer cells to the effects of chemotherapy. Expression of HA-BAD in six separate clonal transfectants from two different ovarian cancer cell lines was found to significantly enhance the cytotoxic effects of paclitaxel, vincristine, and, to a lesser extent, etoposide. Enhancement of paclitaxel-induced apoptosis in HA-BAD-expressing clones was demonstrated by trypan blue exclusion, clonogenic cell assay, and flow cytometric evaluation. Importantly, this effect was associated with binding of HA-BAD to BCL-xL and concomitant disruption of BAX:BCL-xL interaction. Taken together, these data suggest that the development of small molecules which mimic the effects of BAD may represent a new class of drugs capable of preventing or reversing resistance to chemotherapy agents such as paclitaxel.

BAX expression is associated with enhanced intracellular accumulation of paclitaxel: a novel role for BAX during chemotherapy-induced cell death.

SW626 cells that overexpress BAX are sensitized to the cytotoxic effects of paclitaxel and vincristine. It has been assumed that BAX mediates these effects through its ability to alter mitochondrial function, specifically by promoting the release of cytochrome c and facilitating the mitochondrial permeability transition. However, we have found that several early paclitaxel-mediated events are enhanced in SW626 transfectants that overexpress BAX, including G2-M-phase arrest, tubulin polymerization, and BCL-2 phosphorylation. We now demonstrate that these seemingly disparate effects are explained by an enhanced accumulation of paclitaxel in BAX-overexpressing cells, an effect due to diminished drug efflux. In contrast, drug efflux is increased in cells that do not overexpress BAX, resulting in low intracellular paclitaxel levels and relative resistance to the effects of this drug. Drug efflux in SW626 cells is mediated by a verapamil-inhibitable, non-MDR-1, non-MRP-1 transporter whose function or expression may be inhibited by BAX. These data suggest that stable transfectants that overexpress BAX may be sensitized to apoptotic cell death through a novel mechanism involving the enhancement of intracellular levels of naturally occurring toxins such as alkaloid derivatives.

BAX protein expression and clinical outcome in epithelial ovarian cancer.

PURPOSE: Expression of the pro-apoptotic protein BAX sensitizes ovarian cancer cell lines to paclitaxel in vitro by enhancing the pathway of programmed cell death. The present study was performed to determine the relationship between BAX expression and clinical outcome in 45 patients with newly diagnosed ovarian cancer. METHODS: BAX protein expression was analyzed by immunohistochemistry, and its relationship with clinical outcome was determined. Assessment of BAX mRNA transcript levels and mutational analysis of the BAX coding region were also performed. RESULTS: BAX protein was expressed at high levels (defined as > or = 50% of tumor cells positive) in tumor tissue from 60% of newly diagnosed patients. All patients whose tumors expressed high levels of BAX achieved a complete response (CR) to first-line chemotherapy that contained paclitaxel plus a platinum analogue, compared with 57% of patients in the low-BAX group (P = .036). After a median follow-up of 1.9 years, the median disease-free survival (DFS) of patients in the high-BAX group has not been reached, compared with a median DFS of 1.1 years for low-BAX expressors (P = .0061). BAX retained independent prognostic significance in multivariate analysis when corrected for stage and histology. BAX mRNA transcripts were easily detected in samples with low BAX protein expression, and no BAX mutations were identified. CONCLUSION: The correlation between high BAX levels and improved clinical outcome suggests that an intact apoptotic pathway is an important determinant of chemoresponsiveness in ovarian cancer patients who receive paclitaxel.

Radiation-induced apoptosis is not enhanced by expression of either p53 or BAX in SW626 ovarian cancer cells.

The p53 protein is known to play a central role in mediating G1 arrest or apoptosis in response to ionizing radiation in some cell types. It has been proposed that the link between p53 and induction of apoptosis is provided in part by p53-mediated upregulation of BAX. In this study, we used the human SW626 ovarian cancer cell line, which lacks functional p53, to further investigate the relationship between wildtype p53, BAX, and apoptosis. SW626 cells expressing a temperature sensitive (ts) p53 mutant did not undergo G1 arrest or apoptosis and did not exhibit enhanced sensitivity to radiation at the permissive temperature of 32 degrees C. The tsp53 protein was functional in these cells as evidenced by rapid induction of p21 at 32 degrees C, but not at 37 degrees C. Interestingly, restoration of wildtype p53 function at 32 degrees C was not associated with BAX upregulation. In addition, stable overexpression of BAX in SW626 cells was not capable of enhancing apoptotic cell death in response to radiation. Thus, failure of p53 to upregulate BAX is not the sole reason for its inability to promote radiation-induced apoptosis in SW626 cells. Taken together, our data suggest that neither p53 nor BAX upregulation is sufficient for the induction of apoptosis in response to genotoxic damage in some cell types.