Quantitative proteomic analysis of oligodendrogliomas with and without 1p/19q deletion.

Approximately 50-80% of oligodendrogliomas demonstrate a combined loss of chromosome 1p and 19q. Chromosome 1p/19q deletion, appearing early in tumorigenesis, is associated with improved clinical outcomes, including response to chemotherapy and radiation. Although many hypotheses have been proposed, the molecular mechanisms underlying improved clinical outcomes with 1p/19q deletion in oligodendrogliomas have not been characterized fully. To investigate the molecular differences between oligodendrogliomas, we employed an unbiased proteomic approach using microcapillary liquid chromatography mass spectrometry, along with a quantitative technique called isotope-coded affinity tags, on patient samples of grade II oligodendrogliomas. Following conventional biochemical separation of pooled tumor tissue from five samples of undeleted and 1p/19q deleted grade II oligodendrogliomas into nuclei-, mitochondria-, and cytosol-enriched fractions, relative changes in protein abundance were quantified. Among the 442 total proteins identified, 163 nonredundant proteins displayed significant changes in relative abundance in at least one of the three fractions between oligodendroglioma with and without 1p/19q deletion. Bioinformatic analyses of differentially regulated proteins supported the potential importance of metabolism and invasion/migration to the codeleted phenotype. A subset of altered proteins, including the pro-invasive extracellular matrix protein BCAN, was further validated by Western blotting as candidate markers for the more aggressive undeleted phenotype. These studies demonstrate the utility of proteomic analysis to identify candidate biological motifs and molecular mechanisms that drive differential malignancy related to 1p19q phenotypes. Future analysis of larger patient samples are warranted to further refine biomarker panels to predict biological behavior and assist in the identification of deleted gene products that define the 1p/19q phenotype.

TWIST1 promotes invasion through mesenchymal change in human glioblastoma.

BACKGROUND: Tumor cell invasion into adjacent normal brain is a mesenchymal feature of GBM and a major factor contributing to their dismal outcomes. Therefore, better understandings of mechanisms that promote mesenchymal change in GBM are of great clinical importance to address invasion. We previously showed that the bHLH transcription factor TWIST1 which orchestrates carcinoma metastasis through an epithelial mesenchymal transition (EMT) is upregulated in GBM and promotes invasion of the SF767 GBM cell line in vitro. RESULTS: To further define TWIST1 functions in GBM we tested the impact of TWIST1 over-expression on invasion in vivo and its impact on gene expression. We found that TWIST1 significantly increased SNB19 and T98G cell line invasion in orthotopic xenotransplants and increased expression of genes in functional categories associated with adhesion, extracellular matrix proteins, cell motility and locomotion, cell migration and actin cytoskeleton organization. Consistent with this TWIST1 reduced cell aggregation, promoted actin cytoskeletal re-organization and enhanced migration and adhesion to fibronectin substrates. Individual genes upregulated by TWIST1 known to promote EMT and/or GBM invasion included SNAI2, MMP2, HGF, FAP and FN1. Distinct from carcinoma EMT, TWIST1 did not generate an E- to N-cadherin "switch" in GBM cell lines. The clinical relevance of putative TWIST target genes SNAI2 and fibroblast activation protein alpha (FAP) identified in vitro was confirmed by their highly correlated expression with TWIST1 in 39 human tumors. The potential therapeutic importance of inhibiting TWIST1 was also shown through a decrease in cell invasion in vitro and growth of GBM stem cells. CONCLUSIONS: Together these studies demonstrated that TWIST1 enhances GBM invasion in concert with mesenchymal change not involving the canonical cadherin switch of carcinoma EMT. Given the recent recognition that mesenchymal change in GBMs is associated with increased malignancy, these findings support the potential therapeutic importance of strategies to subvert TWIST1-mediated mesenchymal change.

Syndromic craniosynostosis associated with microdeletion of chromosome 19p13.12-19p13.2.

Craniosynostosis, a condition in which the cranial sutures prematurely fuse, can lead to elevated intracranial pressure and craniofacial abnormalities in young children. Currently surgical intervention is the only therapeutic option for patients with this condition. Craniosynostosis has been associated with a variety of different gene mutations and chromosome anomalies. Here we describe three cases of partial deletion of chromosome 19p. Two of the cases present with syndromic craniosynostosis while one has metopic ridging. A review of the genes involved in the rearrangements between the three cases suggests several gene candidates for craniosynostosis. CALR and DAND5, BMP regulators involved in osteoblast differentiation, and MORG1, a mediator of osteoclast dysregulation may play a role in abnormal cranial vault development. Additionally, CACNA1A, a gene that when mutated is associated with epilepsy and CC2D1A, a gene associated with nonsyndromic mental retardation may contribute to additional phenotypic features seen in the patients we describe. In addition, these findings further support the need for genetic testing in cases of syndromic craniosynostosis.

Lumbar CSF shunting preferentially drains the cerebral subarachnoid over the ventricular spaces: implications for the treatment of slit ventricle syndrome.

Based on a proposed pathophysiology of slit ventricle syndrome (SVS), we have hypothesized that lumboperitoneal shunting exerts effects in SVS patients by increasing the buffering capacity for raised intracranial pressure (ICP) via an increase in cerebrospinal fluid drainage from the cerebral subarachnoid space (SAS). We describe 3 SVS patients with patent lumbar subarachnoid drainage but under-functioning ventriculoperitoneal shunts (VPS) who presented with ventriculomegaly (not SVS), and persistence of shunt malfunction like symptoms. Revision of the VPS resulted in complete resolution of symptoms despite a finding of low pressure in the ventricular space. This supports the hypothesis that lumboperitoneal shunting preferentially drains the SAS over the intraventricular space and in these cases allows the 'SVS' ventricles to enlarge by creating a pressure gradient from ventricles to SAS through the cortical mantle.

Noninvasive identification of human central sulcus: a comparison of gyral morphology, functional MRI, dipole localization, and direct cortical mapping.

The locations of the human primary hand cortical somatosensory and motor areas were estimated using structural and functional MRI, scalp-recorded somatosensory-evoked potential dipole localization, expert judgments based on cortical anatomy, and direct cortical stimulation and recording studies. The within-subject reliability of localization (across 3 separate days) was studied for eight normal subjects. Intraoperative validation was obtained from five neurosurgical patients. The mean discrepancy between the different noninvasive functional imaging methods ranged from 6 to 26 mm. Quantitative comparison of the noninvasive methods with direct intraoperative stimulation and recording studies did not reveal a significant mean difference in accuracy. However, the expert judgments of the location of the sensory hand areas were significantly more variable (maximum error, 39 mm) than the dipole or functional MRI techniques. It is concluded that because expert judgments are less reliable for identifying the cortical hand area, consideration of the findings of noninvasive functional MRI and dipole localization studies is desirable for preoperative surgical planning.