Jenny Kan-Suen Pu

Long non-coding RNA expression profiles predict clinical phenotypes in glioma.

Glioma is the commonest form of primary brain tumor in adults with varying malignancy grades and histological subtypes. Long non-coding RNAs (lncRNAs) are a novel class of non-protein-coding transcripts that have been shown to play important roles in cancer development. To discover novel tumor-related lncRNAs and determine their associations with glioma subtypes, we first applied a lncRNA classification pipeline to identify 1970 lncRNAs that were represented on Affymetrix HG-U133 Plus 2.0 array. We then analyzed the lncRNA expression patterns in a set of previously published glioma gene expression profiles of 268 clinical specimens, and identified sets of lncRNAs that were unique to different histological subtypes (astrocytic versus oligodendroglial tumors) and malignancy grades. These lncRNAs signatures were then subject to validation in another non-overlapping, independent data set that contained 157 glioma samples. This is the first reported study that correlates lncRNA expression profiles with malignancy grade and histological differentiation in human gliomas. Our findings indicate the potential roles of lncRNAs in the biogenesis, development and differentiation of gliomas, and provide an important platform for future studies.

Self-assembling peptide nanofiber scaffold promotes the reconstruction of acutely injured brain.

UNLABELLED Traumatic brain injury (TBI) or brain surgery may cause extensive loss of cerebral parenchyma. However, no strategy for reconstruction has been clinically effective. Our previous study had shown that self-assembling peptide nanofiber scaffold (SAPNS) can bridge the injured spinal cord, elicit axon regeneration, and eventually promote locomotor functional recovery. In the present study we investigated the effect of SAPNS for the reconstruction of acutely injured brain. The lesion cavity of the injured cortex was filled with SAPNS or saline immediately after surgically induced TBI, and the rats were killed 2 days, 2 weeks, or 6 weeks after the surgery for histology, immunohistochemistry, and TUNEL studies. Saline treatment in the control animals resulted in a large cavity in the injured brain, whereas no cavity of any significant size was found in the SAPNS-treated animals. Around the lesion site in control animals were many macrophages (ED1 positive) but few TUNEL-positive cells, indicating that the TBI caused secondary tissue loss mainly by means of necrosis, not apoptosis. In the SAPNS-treated animals the graft of SAPNS integrated well with the host tissue with no obvious gaps. Moreover, there were fewer astrocytes (GFAP positive) and macrophages (ED1 positive) around the lesion site in the SAPNS-treated animals than were found in the controls. Thus, SAPNS may help to reconstruct the acutely injured brain and reduce the glial reaction and inflammation in the surrounding brain tissue. FROM THE CLINICAL EDITOR Self-assembling peptide nanofiber scaffold (SAPNS) was reported earlier to bridge the injured spinal cord, elicit axon regeneration, and promote locomotor recovery. In this study the effect of SAPNS for the reconstruction of acutely injured brain was investigated. In SAPNS-treated animals the graft integrated well with the host tissue with no obvious gaps. SAPNS may help to reconstruct the acutely injured brain and reduced the glial reaction and inflammation in the surrounding brain tissue.

A long non-coding RNA signature in glioblastoma multiforme predicts survival

Long non-coding RNAs (lncRNAs) represent the leading edge of cancer research, and have been implicated in cancer biogenesis and prognosis. We aimed to identify lncRNA signatures that have prognostic values in glioblastoma multiforme (GBM). Using a lncRNA-mining approach, we performed lncRNA expression profiling in 213 GBM tumors from The Cancer Genome Atlas (TCGA), randomly divided into a training (n=107) and a testing set (n=106). We analyzed the associations between lncRNA signatures and clinical outcome in the training set, and validated the findings in the testing set. We also validated the identified lncRNA signature in another two independent GBM data sets from Gene Expression Omnibus (GEO), which contained specimens from 68 and 101 patients, respectively. We identified a set of six lncRNAs that were significantly associated with the overall survival in the training set (P≤0.01). Based on this six-lncRNA signature, the training-set patients could be classified into high-risk and low-risk subgroups with significantly different survival (HR=2.13, 95% CI=1.38-3.29; P=0.001). The prognostic value of this six-lncRNA signature was confirmed in the testing set and the two independent data sets. Further analysis revealed that the prognostic value of this signature was independent of age and O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. The identification of the prognostic lncRNAs indicates the potential roles of lncRNAs in GBM pathogenesis. This six-lncRNA signature may have clinical implications in the subclassification of GBM.

The cerebellum's involvement in the judgment of spatial orientation: A functional magnetic resonance imaging study

A functional magnetic resonance imaging (fMRI) study was conducted to integrate the clinical observations of the impaired judgment of spatial orientation of cerebellar patients with recent theoretical discoveries about the role of the cerebellum in cognitive functions. Ten normal healthy male right-handed Chinese postgraduates consented to participate in this study. The experimental task employed was a modified version of Bentons Judgment of Line Orientation Test, administered in a blocked fMRI study. The findings indicated activation of the cerebellar regions, the Hemisphere Lobules IV, VI and Crus I, while the subjects were performing the experimental task of the judgment of the orientation of lines. Furthermore, cortical regions were activated, including the bilateral precuneus (BA 7), the extrastriate regions (BA 19), and the bilateral prefrontal regions (BA 9, 10, 44, 46). The imaging data confirmed that the activity of the cerebellum is associated with judging spatial orientation. The theoretical and clinical implications of the findings are discussed.

Inhibition of prolyl 4-hydroxylase, beta polypeptide (P4HB) attenuates temozolomide resistance in malignant glioma via the endoplasmic reticulum stress response (ERSR) pathways

BACKGROUND Glioblastoma multiforme (GBM), the most aggressive malignant primary brain tumor of the central nervous system, is characterized by a relentless disease recurrence despite continued advancement in surgery, radiotherapy, and chemotherapy. Resistance to temozolomide (TMZ), a standard chemotherapeutic agent for GBM, remains a major challenge. Understanding the mechanisms behind TMZ resistance can direct the development of novel strategies for the prevention, monitoring, and treatment of tumor relapse. METHODS AND RESULTS Our research platform, based on the establishment of 2 pairs of TMZ-sensitive/resistant GBM cells (D54-S and D54-R; U87-S and U87-R), has successfully identified prolyl 4-hydroxylase, beta polypeptide (P4HB) over-expression to be associated with an increased IC50 of TMZ. Elevated P4HB expression was verified using in vivo xenografts developed from U87-R cells. Clinically, we found that P4HB was relatively up-regulated in the recurrent GBM specimens that were initially responsive to TMZ but later developed acquired resistance, when compared with treatment-naive tumors. Functionally, P4HB inhibition by RNAi knockdown and bacitracin inhibition could sensitize D54-R and U87-R cells to TMZ in vitro and in vivo, whereas over-expression of P4HB in vitro conferred resistance to TMZ in both D54-S and U87-S cells. Moreover, targeting P4HB blocked its protective function and sensitized glioma cells to TMZ through the PERK arm of the endoplasmic reticulum stress response. CONCLUSIONS Our study identified a novel target together with its functional pathway in the development of TMZ resistance. P4HB inhibition may be used alone or in combination with TMZ for the treatment of TMZ-resistant GBM.

Use of aspirin in Chinese after recovery from primary intracranial haemorrhage

Intracranial haemorrhage (ICH) accounts for ~35% of all strokes in Chinese. Anti-platelet agent is often avoided after an index event due to the possibility of recurrent ICH. This single-centered observational study included 440 consecutive Chinese patients with a first spontaneous ICH surviving the first month performed during 1996-2010. The subjects were identified, and their clinical characteristics, anti-platelet therapy after ICH, and outcomes including recurrent ICH, ischaemic stroke, and acute coronary syndrome were checked from hospital records. Of these 440 patients, 56 patients (12.7%) were prescribed aspirin (312 patient-aspirin years). After a follow-up of 62.2 ± 1.8 months, 47 patients had recurrent ICH (10.7%, 20.6 per 1,000 patient years). Patients prescribed aspirin did not have a higher risk of recurrent ICH compared with those not prescribed aspirin (22.7 per 1,000 patient-aspirin years vs. 22.4 per 1,000 patient years, p=0.70). Multivariate analysis identified age > 60 years (hazard ratio [HR]: 2.0, 95% confidence interval [CI]: 1.07-3.85, p=0.03) and hypertension (HR: 2.0, 95% CI: 1.06-3.75, p=0.03) as independent predictors for recurrent ICH. In a subgroup analysis including 127 patients with standard indications for aspirin of whom 56 were prescribed aspirin, the incidence of combined vascular events including recurrent ICH, ischaemic stroke, and acute coronary syndrome was statistically lower in patients prescribed aspirin than those not prescribed aspirin (52.4 per 1,000 patient-aspirin years, vs. 112.8 per 1,000 patient-years, p=0.04). In conclusion, we observed in a cohort of Chinese post-ICH patients that aspirin use was not associated with an increased risk for a recurrent ICH.

Outcome of elderly patients undergoing intracranial meningioma resection--a systematic review and meta-analysis.

Abstract Background. Intracranial meningioma is a common condition in the elderly population. Surgical resection in this group of patients may be rendered more hazardous due to the patients’ ageing physiology and to multiple comorbidities. This systematic review and meta-analysis aimed to summarise outcome data of elderly patients undergoing intracranial meningioma resection. Methods. Using Ovid Medline, longitudinal studies published from 2002 to October 2012 with patients aged ≥ 65 years that described outcomes after intracranial meningioma resection were reviewed. Outcome data included mortality, recurrence, complication rate and length of hospital stay (LoS). Grading score systems and covariates for predicting outcome were collected. Pooled estimates of mortality data were calculated in StatsDirect using a random effects method. I2 statistic was used to assess heterogeneity. Results. Thirteen eligible studies with a total of 7010 patients (mean age, 73.6 years) were included, in which 82% patients came from one study. The pooled estimates of 90-day and 1-year mortality from available data were 6.6% (95% confidence interval [CI], 4.6–9.1%; n = 735; I2 = 32.1) and 9.6% (95% CI, 7.0–12.6%; n = 564; I2 = 24.3), respectively. The overall complication rates ranged from 2.7% to 29.8%, and the overall incidence of complications was 20% per patient (range, 3–61%). Other outcome data were heterogeneous mainly due to incomparable study designs. Conclusions. Current evidence indicates satisfactory surgical outcomes in the elderly with intracranial meningiomas, though the risks of complications necessitate careful consideration when deciding to operate. Risk factor analysis emphasised the importance of considering pre-operative status and comorbidities during patient selection. Future research should address the causes and prevention of complications, and compare outcomes between younger and older patients using detailed stratifications of tumour characteristics.

Predictive Value of the HAS-BLED Score for the Risk of Recurrent Intracranial Hemorrhage After First Spontaneous Intracranial Hemorrhage

BACKGROUND Patients who survive intracranial hemorrhage (ICH) are at high risk of recurrence. The Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly (Age >65 years), Drugs/Alcohol Concomitantly (HAS-BLED) score has recently been developed to assess bleeding risk. METHODS This observational study was aimed to investigate the prognostic performance of the HAS-BLED score in predicting recurrent ICH. Consecutive patients (434) with a first spontaneous ICH who were not prescribed antiplatelet or anticoagulation therapy (59.8 ± 15.3 years; men, 62.3%) were recruited. RESULTS Most patients (71.6%) had a HAS-BLED score of >1. After a follow-up of 52.7 months, there were 42 ICH recurrences (2.25 per 100 patient-years). The risk of ICH recurrence increased with HAS-BLED score. Specifically, the risk of ICH recurrence with HAS-BLED score of 1, 2, 3, and 4 were 1.37, 2.38, 3.39, and 2.90 per 100 patient-years, respectively. The sensitivity and specificity of HAS-BLED was 79.1% and 29.2%, respectively, with C-statistic of 0.54 (0.50-0.59). CONCLUSION This study provided data on the risk of ICH recurrence stratified using the HAS-BLED score in patients after an ICH.

CRNDE Expression Positively Correlates with EGFR Activation and Modulates Glioma Cell Growth

BackgroundThe long non-coding RNA CRNDE has emerged as an important regulator in carcinogenesis and cancer progression. While CRNDE has previously been found to be the most highly upregulated lncRNA in glioma, detailed information on its roles in regulating cancer cell growth remains limited.ObjectiveIn the present study, we aimed at exploring the functional roles and underlying mechanisms of CRNDE in glioma.MethodsWe applied microarray data analysis to determine the prognostic significance of CRNDE in glioma patients and its correlation with epidermal growth factor receptor (EGFR) activation. EGFR inhibition was used to confirm the role of EGFR in regulating CRNDE expression. Functional studies were performed upon CRNDE silencing to explore its role in gliomagenesis.ResultsWe confirm that CRNDE acts as an oncogene that is highly up-regulated in glioma, and high CRNDE expression correlates with poor prognosis in glioma patients. We further demonstrate that the expression of CRNDE correlates with EGFR activation. EGF and EGFR tyrosine kinase inhibitor (TKI) enhance and block the up-regulation of CRNDE expression, respectively, suggesting that EGFR signaling may positively regulate CRNDE expression. Functional assays show that CRNDE depletion inhibits glioma cell growth both in vitro and in vivo, and is associated with induced cellular apoptosis with decreased Bcl2/Bax ratio.ConclusionsOur findings suggest that the aberrant expression of CRNDE may be mediated by activated EGFR signaling and play significant roles in gliomagenesis.

Primary Central Nervous System Natural Killer Cell Lymphoma in a Chinese Woman with Atypical 11C-Choline Positron Emission Tomography and Magnetic Resonance Spectrometry Findings

BACKGROUND Primary central nervous system (CNS) natural killer (NK)-cell lymphoma is rare with only 7 cases reported previously. Magnetic resonance spectroscopy (MRS) and [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) are frequently used for disease diagnosis and monitoring. Choline (CHO) PET is gaining popularity for identifying CNS lesions because of its high disease to background radioactivity ratio compared with FDG. Normally, CNS lymphoma shows high choline uptake on CHO-PET and a high choline peak on MRS. We present an unusual case of primary CNS NK-cell lymphoma with high choline uptake but absence of a high choline peak on MRS. CASE DESCRIPTION A 39-year-old woman presented with subacute onset of cognitive deterioration. Magnetic resonance imaging of the brain showed a gadolinium-enhancing lesion in the left temporal lobe. MRS showed suppressed N-acetyl-aspartate and the absence of a high choline peak. CHO-PET confirmed that it was the only hypermetabolic lesion in the body with moderate uptake of choline. The differential diagnoses included encephalitis and neoplasm. She was initially treated for the former but did not respond to steroids, intravenous immunoglobulin, and plasmapheresis. A surgical biopsy later confirmed NK-cell lymphoma. She was then treated as primary CNS NK-cell lymphoma with intravenous and intrathecal chemotherapy. CONCLUSIONS We presented a unique case of primary CNS NK-cell lymphoma with atypical imaging findings characterized by moderately increased uptake of choline without a corresponding high choline peak on MRS. Although CHO-PET was suggestive of malignancy, surgical biopsy was required to confirm the diagnosis.