Cyclic nucleotide phosphodiesterase-1C (PDE1C) drives cell proliferation, migration and invasion in glioblastoma multiforme cells in vitro.

Cyclic nucleotides (cAMP & cGMP) are critical intracellular second messengers involved in the transduction of a diverse array of stimuli and their catabolism is mediated by phosphodiesterases (PDEs). We previously detected focal genomic amplification of PDE1C in >90 glioblastoma multiforme (GBM) cells suggesting a potential as a novel therapeutic target in these cells. In this report, we show that genomic gain of PDE1C was associated with increased expression in low passage GBM-derived cell cultures. We demonstrate that PDE1C is essential in driving cell proliferation, migration and invasion in GBM cultures since silencing of this gene significantly mitigates these functions. We also define the mechanistic basis of this functional effect through whole genome expression analysis by identifying down-stream gene effectors of PDE1C which are involved in cell cycle and cell adhesion regulation. In addition, we also demonstrate that Vinpocetine, a general PDE1 inhibitor, can also attenuate proliferation with no effect on invasion/migration. Up-regulation of at least one of this gene set (IL8, CXCL2, FOSB, NFE2L3, SUB1, SORBS2, WNT5A, and MMP1) in TCGA GBM cohorts is associated with worse outcome and PDE1C silencing down-regulated their expression, thus also indicating potential to influence patient survival. Therefore we conclude that proliferation, migration, and invasion of GBM cells could also be regulated downstream of PDE1C.

Astrocytoma derived short-term cell cultures retain molecular signatures characteristic of the tumour in situ.

The heterogeneity of tumours and uncertainties surrounding derived short-term cell cultures and established cell lines fundamentally challenge the research and understanding of tumour growth and development. When tumour cells are cultured, changes are inevitably induced due to the artificial growth conditions. Several recent studies have questioned how representative established cell lines or derived short-term cell cultures are of the tumour in situ. We have characterised gene expression changes induced by short-term culture in astrocytoma in order to determine whether derived short-term cell cultures are representative of the tumour in situ. In comparison to the majority of studies, paired biopsies and derived short-term cultures were investigated to reduce the effects of long-term culture and inter-tumour variability when comparing biopsies and derived cultures from tumours with the same histology from different individuals. We have used the Affymetrix GeneChip U133A to generate gene expression profiles of 6 paediatric pilocytic astrocytoma (PA) biopsies and derived short-term cell cultures and 3 adult glioblastoma multiforme (GBM) biopsies and derived short-term cultures. Significant differential gene expression is induced by short-term culture. However, when the biopsy and derived short-term cell culture samples were grouped according to tumour type (PA and GBM) a molecular signature of 608 genes showed significant differential expression between the groups. This gene cohort can distinguish PA and GBM tumours, regardless of the sample source, suggesting that astrocytoma derived short-term cultures do retain key aspects of the global tumour expression profile and are representative of the tumour in situ. Furthermore, these genes are involved in pathways and functions characteristic of adult GBM including VEGF signalling, hypoxia and TP53 signalling.

Brain biopsy in dementia.

Brain biopsy has an uncertain role in the diagnosis of dementia. Here we report a retrospective analysis of 90 consecutive cerebral biopsies undertaken for the investigation of dementia in adults at a tertiary referral centre between 1989 and 2003. In most cases (90%), biopsy consisted of a right frontal full thickness resection of cortex, white matter and overlying leptomeninges. Fifty-seven per cent of biopsies were diagnostic: the most frequent diagnoses were Alzheimer's disease (18%), Creutzfeldt-Jakob disease (12%) and inflammatory disorders (9%). Other diagnoses in individual patients included Pick's disease, corticobasal degeneration and other tauopathies, Lewy body dementia, multiple sclerosis, Whipple's disease, progressive multifocal leucoencephalopathy, cerebral autosomal dominant arteriopathy with subcortical ischaemic leucoencephalopathy, vasculopathies and paraneoplastic encephalopathy. The most frequent biopsy finding in the non-diagnostic group and for the series as a whole (37%) was non-specific gliosis variably affecting both cortex and white matter. Complications (11%) included seizures, intracranial and wound infections, and intracranial haemorrhage; there were no deaths or lasting neurological sequelae attributable to the procedure. No trends in diagnostic yield or complication rate over the course of the series were identified. Information obtained at biopsy determined treatment in 11%. A raised cerebrospinal fluid cell count was the only robust predictor of a potentially treatable (inflammatory) process at biopsy. The constellation of behavioural change, raised CSF protein and matched oligoclonal bands in CSF and serum was associated with non-specific gliosis at biopsy. This series underlines the value of cerebral biopsy in the diagnosis of dementia, and suggests that certain clinical and laboratory features may be useful in guiding the decision to proceed to brain biopsy where a treatable disease cannot be excluded by other means.

Evaluation of an MRI-based protocol for cell implantation in four patients with Huntington's disease.

The purpose of this study was to evaluate our surgical protocol for the preparation and delivery of suspensions of fetal tissue into the diseased human brain. We implanted suspensions of human fetal striatal anlage into the right caudate and putamen of four patients with Huntington's disease. Postoperative 3 tesla MR imaging confirmed accurate graft placement. Variability in graft survival was noted and the MR signal changes over 6 months revealed persistent hyperintense signal on T2-weighted images. Our results are consistent with those described by other groups and indicate that our surgical protocol is safe, accurate, and reproducible.

The advantages of frameless stereotactic biopsy over frame-based biopsy.

A comparison study is presented, which examines the outcome, complications and cost of stereotactic brain biopsy performed with a frameless versus a frame-based method. The technique of frameless stereotactic biopsy has been shown previously, in both laboratory and in vivo studies, to achieve a level of accuracy at least equal to frame-based biopsy. The investigators have validated the technique in a large clinical series. The frameless and frame-based series were concurrent, comprising 76 and 79 cases, respectively. The frameless stereotactic technique involved standard needle biopsy, targeted by an image-guidance system and directed by a novel rigid adjustable instrument-holder. Frame-based biopsies were performed with the CRW and Leksell systems. There were no significant differences in the demographics, lesion site, size and pathologies between the groups. Operating theatre occupancy and anaesthetic time were both significantly shorter for the frameless series than the frame-based series (p < 0.0001). In addition, the complication rate in the frameless biopsy series was significantly lower than in the frame-based series (p = 0.018). This resulted in lower ITU bed occupancy (p = 0.02), shorter mean hospital stay (p = 0.0013) and significant cost savings (p = 0.0022) for the frameless stereotactic biopsy group, despite the greater use of more expensive MRI in these cases. This comparison study demonstrates that the superior imaging, target visualization and flexibility of the technique of frameless stereotactic biopsy translates into tangible advantages for safety, time and cost when compared with the current gold-standard of frame-based biopsy. The principles are discussed and the authors propose a definition for the term 'frameless stereotaxy'.

Striatal contribution to cognition: working memory and executive function in Parkinson's disease before and after unilateral posteroventral pallidotomy.

The basal ganglia are intimately connected to the frontal cortex via five fronto-striatal circuits. While the role of the frontal cortex in cognition has been extensively studied, the contribution of the basal ganglia to cognition has remained less clear. In Parkinson's disease, posteroventral pallidotomy (PVP) involves surgical lesioning of the internal section of the globus pallidus (GPi, the final output pathway from the basal ganglia) to relieve the motor symptoms of the disorder. PVP in Parkinson's disease provides a unique opportunity to investigate the impact of disruption of striatal outflow to the frontal cortex on cognition. We assessed executive function and working memory after withdrawal of medication in 13 patients with Parkinson's disease before and 3 months after unilateral PVP compared to 12 age- and IQ-matched normals assessed twice with an interval of 3 months. The tests used were: Wisconsin Card Sorting (WCST), Self-Ordered Random Number Sequences, Missing Digit Test, Paced Visual Serial Addition Test (PVSAT), and Visual Conditional Associative Learning Test (VCALT). After PVP, the patients performed significantly better on the Self-Ordered Random Number Sequences and the WCST, an improvement that was also observed in the normals across the two assessment and is therefore likely to reflect practice effects. Relative to the normals, the patients showed significant differential change following PVP on the Missing Digit Test and PVSAT, on which they performed worse after compared to before surgery, while the controls performed better on the second assessment. For the patients, performance on the VCALT also indicated deterioration after PVP, but the changes approached significance. The side of PVP had no effect on the results. The pattern of change observed 3 months after PVP was maintained at 15-month follow-up. The results suggest that striatal outflow to the frontal cortex may be essential for those aspects of executive function that showed deterioration after PVP.

Unifocal amyloidosis: a rare cause of spinal cord compression.

A 75-year-old man presented with a 3-month history of progressive paraparesis due to an extradural mass causing cord compression at the T7 level of the thoracic spine. He underwent decompressive surgery, and later vertebrectomy and cage fixation. Histologically, the lesion was a localized mass of amyloid associated with a clonal plasma cell infiltrate. Localized 'amyloidomas' of the spine are rare, evolve slowly and often have a good prognosis following surgery.