Casein kinase 1 (CK1) promotes the proliferation and metastasis of glioma cells via the phosphatidylinositol 3 kinase-matrix metalloproteinase 2 (AKT-MMP2) pathway.

BACKGROUND: Glioma is a type of tumor that usually occurs in the adult central nervous system. Protein kinases have become important targets for oncotherapy since they are closely correlated with signal transduction. The role of the casein kinase 1 (CK1) gene in glioma remains to be fully elucidated. METHODS: The mRNA and protein expression of CK1 were analyzed by Realtime PCR, Western blot and immunohistochemistry. The cell behavior was assayed by MTT, Transwell and cell scratch methods. Cell cycle and cell apoptosis were performed by flow cytometer. Construction of stable cell line was completed by lentivirus infection. The nude mouse model was used for in vivo analysis on the role of CK1 by injecting the cells into subcutaneous tissue, tail vein and cerebral cortex. The prognostic role of CK1 in glioma was evaluated using Kaplan-Meier and Cox regression analyses. RESULTS: immunohistochemical staining demonstrated that the expression of CK1 in glioma samples was correlated with the grade of glioma. Survival analysis using Kaplan-Meier and multivariate analysis by Cox regression indicated that CK1 could be used as an independent prognostic marker for glioma. The methyl thiazolyl tetrazolium (MTT), transwell, and cell scratch assays demonstrated that the CK1 gene promoted cell proliferation and invasion through the phosphatidylinositol 3 kinase/matrix metalloproteinase 2 (AKT-MMP2) signaling pathway. In vivo experiments in mice also confirmed the ability of CK1 to enhance tumor proliferation and metastasis, with the metastatic site being the small intestine. CONCLUSIONS: the expression of CK1 was correlated with glioma grade and patient survival and it may enhance glioma proliferation and metastasis via AKT-MMP2 pathway.

microRNA response element­regulated TIKI2 expression suppresses the tumorigencity of malignant gliomas.

Glioma is the most common brain malignancy and has a very poor prognosis. The current treatment options have a minimal benefit on prolonging patient survival time. Accumulating data have shown that the WNT signaling pathway has a critical function in the progression and invasion of glioma. Thus, targeting WNT signaling appears to be an effective anti­glioma strategy. TIKI2 was recently found to suppress the activation of the WNT signaling pathway by post­translationally modifying secreted WNT proteins. The implication of TIKI2 aberrance in cancers and its potential therapeutic effect, however, has not been studied. In the present study, a glioma­specific adenoviral vector was constructed, which was regulated by response elements of miR­124, to express TIKI2 in glioma cells (Ad­TIKI2­124). Ad­TIKI2­124 was found to potently suppress the activation of WNT signaling in glioma cells. This inhibitory effect on the WNT signaling pathway lead to the reduction in proliferation, colony formation ability and invasion of glioma cell lines. In addition, animal experiments confirmed that the expression of the Ad­TIKI2­124 construct could compromise the tumorigenicity of glioma cells in vivo. Furthermore, this glioma­selective TIKI2 expression protected normal cells from toxicity. In conclusion, the present study demonstrated that adenovirus­mediated TIKI2 therapy may be used for glioma treatment and therefore warrants further clinical studies.

[The expression and significance of ANXA2 in human glioma].

AIM: to investigate the relation between the expression of ANXA2 in human glioma and its pathological grades, and research the possibility that if ANXA2 could be as a useful diagnostic marker for glioma. METHOD: Semi-quantity RT-PCR and immunohistochemistry were proceeded fro corresponding specimens to detect the level of ANXA2 and ANXA2mRNA. RESULTS: In RT-PCR, the expression level of ANXA2mRNA in glioma was higher than that in surrounding brain tissue. (P < 0.05), as the same, in immunohistochemistry, the expression level of ANXA2 in glioma is higher than that is surrounding brain tissues (P< 0.05). CONCLUSION: ANXA2 expression was much higher in glioma samples than in the surrounding brain tissues, and positive correlation between its expression and pathological grades was found. It could be used as an assistant diagnostic index for glioma.

[Expression and significance of ABCG2 in human malignant glioma].

BACKGROUND & OBJECTIVE: ATP-binding cassette transporter protein ABCG2 is a marker derived from hematopoietic stem cells. However, its role in tumorigenesis and malignant progression of glioma is unclear. This study was to investigate the expression and significance of ABCG2 in gliomas of different malignant grades. METHODS: A microarray chip containing glioma tissues of different malignant grades, implanted glioma xenografts in nude mice, spheroids of glioma cell lines and glioma stem cells was prepared and examined for the expression of ABCG2 with immunohistochemical staining. RESULTS: The positive rate of ABCG2 was 26.8% in the 71 specimens of human glioma tissues, with 11.1% in grade I gliomas, 8% in grade II gliomas, 43.5% in grade III gliomas, and 42.9% in grade IV gliomas; it was significantly higher in grade III-IV gliomas than in grade I-II gliomas (chi2=10.710, P=0.001). The positive rate of ABCG2 was 100% in implanted glioma xenografts in nude mice, gliomas stem cells, and neural stem cells. It was also expressed in some normal tissues. The positive cells surrounded and invaded into vessels in glioma tissues. CONCLUSIONS: ABCG2 is overexpressed in glioma stem cells, glioma tissues of higher grades, and implanted glioma xenografts. The positive cells distribute around vessels in glioma tissues.

Expression change of stem cell-derived neural stem/progenitor cell supporting factor gene in injured spinal cord of rats.

OBJECTIVE: To explore the expression change of stem cell-derived neural stem/progenitor cell supporting factor (SDNSF) gene in the injuried spinal cord tissues of rats, and the relation between the expressions of SDNSF and nestin. METHODS: The spinal cord contusion model of rat was established according to Allen's falling strike method. The expression of SDNSF was studied by RT-PCR and in situ hybridization (ISH), and the expression of nestin was detected by immunochemistry. RESULTS: RT-PCR revealed that SDNSF mRNA was upregulated on day 4 after injury, peaked on day 8-12, and decreased to the sham operation level on day 16. ISH revealed that SDNSF mRNA was mainly expressed in the gray matter cells, probably neurons, of spinal cord. The immunohistochemistry showed that accompanied with SDNSF mRNA upregulation, the nestin-positive cells showed erupted roots, migrated peripherad and proliferation on the 8-day slice. However, the distribution pattern of these new cells was different from that of SDNSF-positive cells. CONCLUSION: (1) SDNSF is expressed in the gray matter of spinal cord. The expression of SDNSF mRNA in the spinal cord varies with injured time. (2) The nestin-positive cells proliferate accompanied with spinal cord injury repair, but do not secrete SDNSF.

[Proteomic analysis of rat astrocytes and C6 glioma cells].

OBJECTIVE: To compare the protein profiles between glioma cells and normal astrocytes. METHODS: Proteomic assay was performed on human C6 glioma cells and purified SD rat astrocytes. Two-dimensional gel electrophoresis (2-DE) and PDQuest software were applied for the comparison of protein image between the C6 cells and astrocytes. The differential protein spots were identified with Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and further bioinformatic analysis. The differential expression of the interesting genes was confirmed by semi-quantitative RT-PCR. RESULTS: Twenty-four differential protein spots were revealed by 2-DE assay. The peptide mass fingerprints (PMFs) of 17 proteins were obtained by MALDI-TOF-MS. Among them, six proteins were determined by further bioinformatic analysis. Compared with the expression level in astrocytes, the identified proteins showed higher expression level in the C6 glioma cells including phosphoglycerate mutase 1, glutathione S-transferase P (GST P), annexin A2 and calreticulin, while the proteins showed lower expression level included vimentin and gamma-actin. The results of RT-PCR confirmed the differential expressions of phosphoglycerate mutase 1, annexin A2 and vimentin identified by 2-DE assay. CONCLUSION: The identified proteins differentially expressed in C6 cells and astrocytes are associated with many important cellular processes and functions such as anaerobic glycolysis, cytoskeleton organization, biotransformation, and signal transduction, and play important roles in tumor growth, migration, and anti-cancer drug resistance.

Human plasma DNP level after severe brain injury.

OBJECTIVE: To determine the relationship between DNP level after human severe brain injury and hyponatremia as well as isorrhea. METHODS: The peripheral venous plasma as control was collected from 8 volunteers. The peripheral venous plasma from 14 severe brain injury patients were collected in the 1, 3, 7 days after injury. Radioimmunoassay was used to detect the DNP concentration. Meanwhile, daily plasma and urine electrolytes, osmotic pressure as well as 24 h liquid intake and output volume were detected. RESULTS: The normal adult human plasma DNP level was 62.46 pg/ml+/-27.56 pg/ml. In the experimental group, the plasma DNP levels were higher from day 1 to day 3 in 8 of the 14 patients than those in the control group (P(1)=0.05, P(3)=0.03). Negative fluid balance occurred in 8 patients and hyponatremia in 7 patients. The increase of plasma DNP level was significantly correlated with the development of a negative fluid balance (r =-0.69, P<0.01) and hyponatremia (chi(2) =4.38, P<0.05). CONCLUSIONS: The increase of plasma DNP level is accompanied by the enhancement of natriuretic and diuretic responses in severe brain-injured patients, which is associated with the development of a negative fluid balance and hyponatremia after brain injury.

[Inhibition of human glioma cell growth by a soluble recombinant human CD40 ligand].

BACKGROUND & OBJECTIVE: CD40 presents on B cells, monocytes, dendritic cells, and endothelial cells, as well as a variety of neoplastic cell types, including carcinomas. CD40 stimulated by its antibody or CD40 ligand previously had been demonstrated to induce activation-induced cell death in ovarian carcinoma cell lines, colon carcinoma cell lines, breast carcinoma cell lines, and lung carcinoma cell lines and to inhibit their growth in vivo. This study was designed to assess the effects of a recombinant soluble human CD40 ligand (srhCD40L) on human glioma cell lines. METHODS: The specimens of human glioma were examined for CD40 expression by immunohistochemistry. The human glioma cell lines were examined for CD40 expression by flow cytometry. The cell lines were incubated with srhCD40L for 24h and 72h, then the markers of proliferation and apoptosis of these cells were determined, respectively. RESULTS: CD40 expression could be detected in 7/23 human glioma specimens and 1/3 cell line. The srhCD40L inhibited the proliferation of CD40+ human glioma cell line. The viability of these cells was decreased from 98% to 87%. The apoptosis and death of these cells were increased by 17.4%. CONCLUSIONS: CD40 stimulated by its ligand directly inhibits human glioma cell growth in vitro. These results suggest that srhCD40L may be of clinic use to inhibit glioma growth.