Hailiang Tang

Analysis of Gene Expression Profiling in Meningioma: Deregulated Signaling Pathways Associated with Meningioma and EGFL6 Overexpression in Benign Meningioma Tissue and Serum

Molecular mechanisms underlying the pathogenesis of meningioma are not fully elucidated. In this study, we established differential gene expression profiles between meningiomas and brain arachnoidal tissue by using Affymetrix GeneChip Human U133 Plus 2.0 Array. KEGG pathway analysis demonstrated that PI3K/Akt and TGFβ signaling pathways were up-regulated in fibroblastic meningioma, and focal adhesion and ECM-receptor interaction pathways were activated in anaplastic meningioma. EGFL6 was one of the most up-regulated genes in fibroblastic meningioma by microarray analysis. Quantitative real-time PCR demonstrated that benign meningiomas had significantly higher levels of EGFL6 mRNA than brain arachnoidal tissue and atypical and anaplastic meningiomas (P<0.001). EGFL6 gene was also highly expressed in ovarian cancer, but expressed lowly in other investigated tumors. ELISA analysis showed that patients with benign meningiomas and ovarian cancers had the highest serum levels of EGFL6 (mean concentration: 672 pg/ml for benign meningiomas, and 616 pg/ml for ovarian cancers). Healthy people and patients with other tumors, however, had low levels of serum EGFL6. In conclusion, we proposed that activation of PI3K/Akt and integrin-mediated signaling pathways was involved in the pathogenesis of benign and anaplastic meningiomas, respectively. We also presented evidence that EGFL6 was overexpressed in benign meningioma tissues and serum.

ZFX regulates glioma cell proliferation and survival in vitro and in vivo.

The zinc finger transcription factor ZFX functions as an important regulator of self-renewal in multiple stem cell types, as well as a sex determinant of mammals. Moreover, ZFX expression is abnormally elevated in several cancers, and correlates with malignancy grade. To investigate its role in the pathogenesis of gliomas, we used lentivirus-mediated RNA interference (RNAi) to knockdown ZFX expression in human glioma cell lines. Our results demonstrate that ZFX plays a crucial role in glioma proliferation and survival, confirming recent reports. We also show for the first time that ZFX knockdown decreases the in vivo growth potential of U87 glioma xenografts in both subcutaneous and intracranial models in nude mice. We conclude that lentivirus-mediated RNAi targeting of ZFX may serve as a promising strategy for glioma therapy.

Tracking Induced Pluripotent Stem Cells–Derived Neural Stem Cells in the Central Nervous System of Rats and Monkeys

Despite of the immense breakthroughs of induced pluripotent stem cells (iPSCs), clinical application of iPSCs and their derivates remains hampered by a lack of definitive in vivo studies. Here, we attempted to track iPSCs-derived neural stem cells (NSCs) in the rodent and primate central nervous system (CNS) and explore their therapeutic viability for stem cell replacement in traumatic brain injury (TBI) rats and monkeys with spinal cord injury (SCI). Superparamagnetic iron oxide (SPIO) particles were used to label iPSCs-derived NSCs in vitro. Labeled NSCs were implanted into TBI rats and SCI monkeys 1 week after injury, and then imaged using gradient reflection echo (GRE) sequence by 3.0T magnetic resonance imaging (MRI) scanner. MRI analysis was performed at 1, 7, 14, 21, and 30 days, respectively, following cell transplantation. Pronounced hypointense signals were initially detected at the cell injection sites in rats and monkeys and were later found to extend progressively to the lesion regions, demonstrating that iPSCs-derived NSCs could migrate to the lesion area from the primary sites. The therapeutic efficacy of iPSCs-derived NSCs was examined concomitantly through functional recovery tests of the animals. In this study, we tracked iPSCs-derived NSCs migration in the CNS of TBI rats and SCI monkeys in vivo for the first time. Functional recovery tests showed obvious motor function improvement in transplanted animals. These data provide the necessary foundation for future clinical application of iPSCs for CNS injury.

Intraoperative ultrasound assistance in resection of intracranial meningiomas

OBJECTIVE Intracranial meningiomas, especially those located at anterior and middle skull base, are difficult to be completely resected due to their complicated anatomy structures and adjacent vessels. Its essential to locate the tumor and its vessels precisely during operation to reduce the risk of neurological deficits. The purpose of this study was to evaluate intraoperative ultrasonography in displaying intracranial meningioma and its surrounding arteries, and evaluate its potential to improve surgical precision and minimize surgical trauma. METHODS Between December 2011 and January 2013, 20 patients with anterior and middle skull base meningioma underwent surgery with the assistance of intraoperative ultrasonography in the Neurosurgery Department of Shanghai Huashan Hospital. There were 7 male and 13 female patients, aged from 31 to 66 years old. Their sonographic features were analyzed and the advantages of intraoperative ultrasonography were discussed. RESULTS The border of the meningioma and its adjacent vessels could be exhibited on intraoperative ultrasonography. The sonographic visualization allowed the neurosurgeon to choose an appropriate approach before the operation. In addition, intraoperative ultrasonography could inform neurosurgeons about the location of the tumor, its relation to the surrounding arteries during the operation, thus these essential arteries could be protected carefully. CONCLUSIONS Intraoperative ultrasonography is a useful intraoperative technique. When appropriately applied to assist surgical procedures for intracranial meningioma, it could offer very important intraoperative information (such as the tumor supplying vessels) that helps to improve surgical resection and therefore might reduce the postoperative morbidity.

ClC-2 contributes to tonic inhibition mediated by α5 subunit-containing GABAA receptor in experimental temporal lobe epilepsy

Temporal lobe epilepsy (TLE), characterized by spontaneous recurrent seizures, learning and memory impairments is associated with neurodegeneration, abnormal reorganization of the circuitry and loss of functional inhibition in hippocampus. In adult hippocampus, the GABAergic cells mediate the major inhibitory function of the principal neurons, promoting the Cl(-) entry through the GABA(A) receptor, whether through phasic (synaptic) or tonic (extrasynaptic) conductance. Aside from classical synaptic component, tonic GABAergic inhibition mediated by extrasynaptic GABA(A) receptor received increasing attention over the past years. There is growing evidence that tonic inhibition plays an important role in epilepsy, memory and cognition. Since GABA(A) receptor-mediated inhibition depends on the maintenance of intracellular Cl(-) concentration at low levels in mature neurons, a shift in E(cl) is likely to participate in the generation and not merely a consequence of TLE. As we know, chloride channel-2 (ClC-2) is a member of the supergene family of voltage-gated chloride channels, it constitutes part of the background conductance and is involved in chloride extrusion. Here we show that ClC-2 were upregulated functionally in CA1 pyramidal cells in pilocarpine-treated rats, and that an observed increase in ClC-2 currents in CA1 pyramidal cells was reversed by L655,708, a specific antagonist of α5 subunit-containing GABA(A) receptor.

Clinicopathological analysis of rhabdoid meningiomas: report of 12 cases and a systematic review of the literature.

BACKGROUND Rhabdoid meningioma (RM) is a rare subtype of meningioma, classified as World Health Organization grade III with a poor prognosis. Here we present our experience on RM and review relevant literature in an attempt to investigate the clinical features, treatment, and prognosis of these tumors. METHODS Twelve patients underwent surgical treatment for intracranial RMs between 2003 and 2008 in our department. The clinical data, radiological manifestations, pathological findings, treatments, and prognoses of the patients were analyzed retrospectively; 58 other cases reported previously by other institutions also were summarized and reviewed. RESULTS These cases (6 men and 6 women, mean age 44.3 years old, ranging from 21 to 78 years old) constituted 0.28% of all meningioma patients admitted at our department during the same period. The mean duration of symptoms was relatively short at 1.6 months. There was no significant clinical manifestation noted, and the radiologic findings fell into 3 types of images. In the follow-up period of over 30 months, 7 patients died; 5 patients had recurrence and 2 patients died of unknown causes. CONCLUSIONS RM is a rare subtype of malignant meningioma featuring an increased tendency for recurrence and possible metastasis. It is still difficult to make a correct preoperative diagnosis. The overall prognosis for these patients is extremely poor, and the role of various adjuvant treatments needs to be further studied.

Analysis of prognostic factors and treatment of anaplastic meningioma in China

Meningioma is the most frequently reported primary brain and central nervous system tumor. However, malignant meningioma is rare with the anaplastic subtype the most common. This subtype of meningioma is fatal with a high recurrence rate and poor survival. A retrospective review of anaplastic meningioma patients treated in one of the largest neurosurgical centers in China between 2003 and 2008 was conducted. From 70 identified patients, seven were lost to follow-up, but the remaining 63 patients were studied for prognostic factors. The mean follow-up time was 84.9±standard deviation (SD) of 19.7months. Tumor recurred in 35 out of 63 (55.6%) patients. Thirty-three (52.4%) patients had died by the most recent follow-up, and the median overall survival (OS) was 70.0±9.7months. The 3year and 5year survival rates were 68.3% and 54.7%, respectively. The median progression-free survival (PFS) was 52.0±9.9months, whereas the 3year and 5year PFS rates were 60.2% and 43.9%, respectively. We found that preoperative KPS, extent of tumor resection, radiotherapy, tumor location and previous history of meningioma were factors related to PFS. In the non-recurrent group, the preoperative Karnofsky Performance Scale (KPS), extent of tumor resection and radiotherapy correlated with PFS. However, multivariate analysis identified radiotherapy as the only independent factor affecting PFS (p=0.007). Additionally, MIB-1 proliferation index failed to identify a cut-off point to predict the prognosis for anaplastic meningioma. This study provides an overview of the epidemiology and treatment of anaplastic meningioma in China using a large population.

CD133-Positive Cells Might Be Responsible for Efficient Proliferation of Human Meningioma Cells

Owing to lack of appropriate model systems, investigations of meningioma biology have come to a stop. In this study, we developed a comprehensive digestion method and defined a culture system. Using this method and system, primary meningioma cells in conditioned suspension medium and a hypoxic environment could be amplified in spheres and were passaged for more than ten generations. Meningioma sphere cells were positive for meningioma cell markers and negative for markers of neural cell types. Importantly, we found the cells expressed the stem cell marker, CD133, but not nestin. All of the tumor sphere cell populations showed a slower degree of cell proliferation than that of human glioma cells and fetal neural stem cells (NSCs). Further studies showed that the proliferative rate was positively correlated with CD133 expression. The higher the CD133 expression, the faster the cell proliferation. With the increase in cell generations, the cell proliferation rate gradually slowed down, and CD133 expression also decreased. Single CD133+ cells rather than CD133− cells could form spheres. Thus, the results above indicated that those cells expressing CD133 in spheres might be stem-like cells, which may be responsible for efficient amplification of human meningioma cells. Decreased expression of CD133 may lead to the failure of long-term passaging.

Clinicopathological analysis of metaplastic meningioma: report of 15 cases in Huashan Hospital.

OBJECTIVE Metaplastic meningioma is a rare subtype of benign meningiomas, classified as WHO grade I with well prognosis. Here we presented our experiences on 15 cases of metaplastic meningioma, to investigate the clinicopathological features, therapies and prognosis of these cases. METHODS 15 patients underwent surgical treatment for intracranial metaplastic meningioma between 2001 and 2010 at Neurosurgery Department of Huashan Hospital, Shanghai, China. The clinical data, radiological manifestation, treatment strategy, pathological findings and prognosis of all patients were analyzed retrospectively. RESULTS Among the 15 cases (10 males and 5 females), the age ranged from 22 to 74 years old (the mean age was 50.67-year old). The clinical manifestations include headache, dizziness, seizure attack, vision decrease, and weakness of bilateral lower limbs. All the patients received surgical treatment, combined with radiotherapy in some cases. In the follow-up period, recurrence occurred in 2 cases, of which 1 patient died of other system complications. CONCLUSIONS Metaplastic meningiomas are characterized by focal or widespread mesenchymal differentiation with formation of bone, cartilage, fat, and xanthomatous tissue elements. Surgical removal is the optimal therapy, and the overall prognosis is well. But recurrence may occur in some cases, thus radiotherapy is necessary for such kind of patients.

KLF4 is a tumor suppressor in anaplastic meningioma stem-like cells and human meningiomas

Meningiomas are the most common primary tumors in central nervous system. While recent studies have revealed genetic clues to lower grade human meningiomas, the molecular determinants driving the progression and recurrence of anaplastic meningioma, the most malignant subtype with a low prevalence but high morbidity, are still poorly understood. It has been proposed that high recurrence rates of malignant meningiomas are linked to cancer stem cells. Indeed, tumor stem-like cells have been isolated from various meningioma subtypes, but never been obtained from anaplastic meningioma. In this study, we successfully isolated stem-like cells from human anaplastic meningioma. These cells are capable of forming spheres and initiating xenograft tumors that recapitulate anaplastic meningioma phenotypes, and thus could serve as an in vitro model for malignant meningiomas. KLF4, a transcription factor known for its role in stemness maintenance, was identified as one of the most frequently mutated genes in the benign secretory meningioma. Interestingly, we found that KLF4 is downregulated in anaplastic meningioma compared with low-grade meningioma subtypes. By manipulating KLF4 expression in anaplastic meningioma stem-like cells, we demonstrated that KLF4 acts as a tumor suppressor during malignant progression in meningioma, affecting apoptosis, proliferation, invasion, and cell cycle. These results suggest a potential therapeutic value of KLF4 for clinical intervention of anaplastic meningioma.