Daofeng Tian

Glioma Stem Cell-Targeted Dendritic Cells as a Tumor Vaccine Against Malignant Glioma

Purpose Cancer stem cells have recently been thought to be closely related to tumor development and reoccurrence. It may be a promising way to cure malignant glioma by using glioma stem cell-targeted dendritic cells as a tumor vaccine. In this study, we explored whether pulsing dendritic cells with antigens of glioma stem cells was a potent way to induce specific cytotoxic T lymphocytes and anti-tumor immunity. Materials and Methods Cancer stem cells were cultured from glioma cell line U251. Lysate of glioma stem cells was obtained by the repeated freezing and thawing method. Dendritic cells (DCs) were induced and cultured from the murine bone marrow cells, the biological characteristics were detected by electron microscope and flow cytometry. The DC vaccine was obtained by mixing DCs with lysate of glioma stem cells. The DC vaccine was charactirizated through the mixed lymphocyte responses and cell killing experiment in vitro. Level of interferon-γ (IFN-γ) in the supernatant was checked by ELISA. Results After stimulation of lysate of glioma stem cell, expression of surface molecules of DC was up-regulated, including CD80, CD86, CD11C and MHC-II. DCs pulsed with lysate of glioma stem cells were more effective than the control group in stimulating original glioma cells-specific cytotoxic T lymphocytes responses, killing glioma cells and boosting the secretion of IFN-γ in vitro. Conclusion The results demonstrated DCs loaded with antigens derived from glioma stem cells can effectively stimulate naive T cells to form specific cytotoxic T cells, kill glioma cells cultured in vitro.

Clinical and Imaging Characteristics of Cerebral Schistosomiasis

In recent years, there has been a trend for increased incidence of cerebral schistosomiasis. It is often misdiagnosed because of the diversity of clinical symptoms. We wished to explore clinical characteristics and imaging findings in cerebral schistosomiasis. We retrospectively analyzed clinical data, laboratory tests, CT, and MRI results in 11 patients with cerebral schistosomiasis. All patients had chronic cerebral schistosomiasis (five with epilepsy type, five with brain tumor type, and one patient with stroke type). All patients with brain tumor type were misdiagnosed as having gliomas. There were typical findings on CT and MRI. In conclusion, clinical manifestations of cerebral schistosomiasis are variable, and the rate of misdiagnosis is high. For more precise diagnosis, a combination of laboratory and imaging data is required.

BMP4 reverses multidrug resistance through modulation of BCL-2 and GDNF in glioblastoma.

Patients with glioblastoma are commonly treated with chemotherapy. But a significant proportion of patients develop disease progression after an initial response to chemotherapy. Presently, there is no standard of care for such patients. The bone morphogenetic protein 4 (BMP4) has been reported to play a tumor-suppressing role in glioblastoma, but its role in glioblastoma multidrug resistance (MDR) is not clear. We reported that BMP4 can reverse MDR of glioblastoma through the inhibition of B-cell lymphoma 2(BCL-2) and glial cell derived neurotrophic factor (GDNF). We showed that the expression level of BMP4 was lower in glioblastoma compared to normal brain tissue, and also showed that BMP4 expression decreased in multidrug resistance cell line U251/TMZ compared to U251 cells. Our research demonstrated that over-expression of BMP4 can reverse the multidrug resistance. BCL-2 and GDNF were inhibited when BMP4 was over-expressed, and this data were consistent with the negative relationship in human samples; analysis of 40 patients glioblastoma and brain samples revealed a significant negative correlation between BMP4 and BCL-2, GDNF. When BCL-2 and GDNF were knocked down, the effect of BMP4 in regulating MDR was partially lost. This novel result showed, for the first time, that BMP4 can reverse MDR in glioblastoma, which involved negative inhibition of BCL-2 and GDNF.

LRIG1 enhances chemosensitivity by modulating BCL-2 expression and receptor tyrosine kinase signaling in glioma cells.

Purpose Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) are an inhibitor of receptor tyrosine kinases (RTKs) that was discovered in recent years, and many studies showed that LRIG1 is a tumor suppressor gene and may be related to tumor drug resistance. In this study, we explored whether LRIG1 protein expression can improve the chemosensitivity of glioma cells and what was its mechanism. Materials and Methods We collected 93 cases of glioma tissues and detected the expression of LRIG1 and BCL-2. We constructed a multidrug resistance cell line U251/multidrug resistance (MDR) and examined the change of LRIG1 and BCL-2 at mRNA and protein expression levels. LRIG1 expression was upregulated in U251/MDR cells and we detected the change of multidrug resistance. Meanwhile, we changed the expression of LRIG1 and BCL-2 and explored the relationship between LRIG1 and BCL-2. Finally, we also explored the relationship between LRIG1 and RTKs. Results LRIG1 was negatively correlated with BCL-2 expression in glioma tissue and U251/MDR cells, and upregulation of LRIG1 can enhance chemosensitivity and inhibit BCL-2 expression. Furthermore, LRIG1 was negatively correlated with RTKs in U251/MDR cells. Conclusion These results demonstrated that LRIG1 can improve chemosensitivity by modulating BCL-2 expression and RTK signaling in glioma cells.

Downregulation of RND3/RhoE in glioblastoma patients promotes tumorigenesis through augmentation of notch transcriptional complex activity

Activation of Notch signaling contributes to glioblastoma multiform (GBM) tumorigenesis. However, the molecular mechanism that promotes the Notch signaling augmentation during GBM genesis remains largely unknown. Identification of new factors that regulate Notch signaling is critical for tumor treatment. The expression levels of RND3 and its clinical implication were analyzed in GBM patients. Identification of RND3 as a novel factor in GBM genesis was demonstrated in vitro by cell experiments and in vivo by a GBM xenograft model. We found that RND3 expression was significantly decreased in human glioblastoma. The levels of RND3 expression were inversely correlated with Notch activity, tumor size, and tumor cell proliferation, and positively correlated with patient survival time. We demonstrated that RND3 functioned as an endogenous repressor of the Notch transcriptional complex. RND3 physically interacted with NICD, CSL, and MAML1, the Notch transcriptional complex factors, promoted NICD ubiquitination, and facilitated the degradation of these cofactor proteins. We further revealed that RND3 facilitated the binding of NICD to FBW7, a ubiquitin ligase, and consequently enhanced NICD protein degradation. Therefore, Notch transcriptional activity was inhibited. Forced expression of RND3 repressed Notch signaling, which led to the inhibition of glioblastoma cell proliferation in vitro and tumor growth in the xenograft mice in vivo. Downregulation of RND3, however, enhanced Notch signaling activity, and subsequently promoted glioma cell proliferation. Inhibition of Notch activity abolished RND3 deficiency‐mediated GBM cell proliferation. We conclude that downregulation of RND3 is responsible for the enhancement of Notch activity that promotes glioblastoma genesis.

RND3 promotes Snail 1 protein degradation and inhibits glioblastoma cell migration and invasion

Activation of Snail1 signaling promotes the migration and invasion of multiple tumors, including glioblastoma multiforme (GBM). However, the molecular mechanism that augments Snail1 signaling during GBM cell migration and invasion remains largely unknown. Identification of the factors that regulate Snail1 signaling is critical to block tumor cell migration and invasion. By screening human GBM specimens, we found that the expression levels of small GTPase RND3 positively correlated with the expression levels of E-cadherin and claudin, the glioblastoma migration biomarkers negatively regulated by Snail1. Downregulation of E-cadherin and claudin has been associated with the migration and invasion of GBM cells. We demonstrated that RND3 functioned as an endogenous inhibitor of the Snail-directed transcriptional regulation. RND3 physically interacted with Snail1 protein, enhanced Snail1 ubiquitination, and facilitated the protein degradation. Forced expression of RND3 inhibited Snail1 activity, which in turn blocked glioblastoma cell migration and invasion in vitro in cell culture and in vivo in GBM xenograft mice. In contrast, downregulation of RND3 augmented Snail1 activity, and subsequently decreased E-cadherin expression, eventually promoted glioblastoma cell migration and invasion. The pro-migration induced by RND3 downregulation was attenuated by Snail1 knockdown. The findings partially explain why Snail1 activity is augmented in GBM, and defines a new function of RND3 in GBM cell migration and invasion.

LRIG1 Improves Chemosensitivity Through Inhibition of BCL-2 and MnSOD in Glioblastoma

We have reported that Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) can improve the chemosensitivity in U251 cells. However, the underlying mechanisms how LRIG1 improves the chemosensitivity remain unknown. In this study, we reported that LRIG1 can improve the chemosensitivity through the inhibition of B cell lymphoma 2 (BCL-2) and manganese superoxide dismutase (MnSOD). In addition, we showed that the expression level of LRIG1 was significantly negatively correlated with BCL-2 and MnSOD expression in glioma. Our research demonstrated that overexpression of LRIG1 can enhance the chemosensitivity. BCL-2 and MnSOD were inhibited in LRIG1 overexpressing cells. On the other hand, when BCL-2 and MnSOD were knocked down, the chemosensitivity of U251 cells decreased, and the effect of LRIG1 in regulating chemosensitivity was compromised. For the first time, our results showed that LRIG1 can enhance chemosensitivity in glioblastoma by inhibition of BCL-2 and MnSOD.

Photodynamic therapy mediated by 5-aminolevulinic acid suppresses gliomas growth by decreasing the microvessels

SummaryAlthough 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy (PDT) has been demonstrated to be a novel and effective therapeutic modality for some human malignancies, its effect and mechanism on glioma are still controversial. Previous studies have reported that 5-ALA-PDT induced necrosis of C6 rat glioma cells in vitro. The aim of this study was to further investigate the effect and mechanism of 5-ALA-PDT on C6 gliomas implanted in rats in vivo. Twenty-four rats bearing similar size of subcutaneously implanted C6 rat glioma were randomly divided into 3 groups: receiving 5-ALA-PDT (group A), laser irradiation (group B), and mock procedures but without any treatment (group C), respectively. The growth, histology, microvessel density (MVD), and apoptosis of the grafts in each group were determined after the treatments. As compared with groups B and C, the volume of tumor grafts was significantly reduced (P<0.05), MVD was significantly decreased (P<0.001), and the cellular necrosis was obviously increased in group A. There was no significant difference in apoptosis among the three groups. The in vivo studies confirmed that 5-ALA-PDT may be an effective treatment for gliomas by inhibiting the tumor growth. The mechanism underlying may involve increasing the cellular necrosis but not inducing the cellular apoptosis, which may result from the destruction of the tumor microvessels.

Neuroendoscopic fenestration of the septum pellucidum for monoventricular hydrocephalus

OBJECTIVES Monoventricular hydrocephalus (MH) is a rare condition in which the site of obstruction is located around one of the interventricular foramen. In this paper, the authors offer their experiences in the neuroendoscopic management of this uncommon type of hydrocephalus. PATIENTS AND METHODS The authors retrospectively reviewed 12 neuroendoscopic procedures performed between July 2003 and June 2011 with MH. Clinical and radiological charts were reviewed and analysed. RESULTS The operative course is a simple and successful procedure, and the postoperative complaints are mild. The postoperative radiological findings showed maintenance of ventricular enlargement in four cases and a significant decrease in enlargement in eight patients. However, upon shifting of the septum pellucidum, the periventricular transudation disappeared in all patients. CONCLUSIONS Fenestration of the septum pellucidum by neuroendoscope is the best treatment for patients with monoventricular hydrocephalus. The approach for fenestration of the septum pellucidum is based on the experience of the neurosurgeon and the preoperative planning.

Magnetic Resonance Imaging of Plaque Burden in Vascular Walls of the Middle Cerebral Artery Correlates with Cerebral Infarction.

Intracranial atherosclerosis may be related to the risk of ischemic stroke. High-resolution magnetic resonance imaging (H-R MRI) makes it possible to measure the intracranial atheroma in vivo. The aim of this study was to evaluate the plaque burden of the middle cerebral artery (MCA) using H-R MRI, and to determine its relationship with both cerebral infarction size and plaque burden in the carotid artery (CA). 54 patients with MCA territory infarction were enrolled and HR-MRI was performed within 7 days following stroke onset. The lumen area (LA), wall area (WA), total vessel area (TVA), and the normalized wall index (NWI) of MCA and CA were measured. We analyzed the status of MCA and CA atheroma, and the size of cerebral infarction, in the corresponding vascular territory. We observed a significant positive correlation between the NWI of the index artery and the volume of the ipsilateral ischemic lesions. In addition, the mean NWI of MCA was significantly correlated with that of the ipsilateral CA (left, r = 0.88, P.0.001; right, r = 0.79, P.0.001), and the plaque burden of the M1 segment of MCA was significantly higher than that of the ipsilateral CA (P < 0.05). There was no significant correlation between the TVA and WA of MCA and that of CA. Our findings suggest that MCA atherosclerosis is significantly correlated with cerebral infarction. In ischemic stroke patients, the plaque burden of M1 segment of MCA is more significant than that of CA.