Objectives: Intracranial atherosclerosis, especially the middle cerebral artery (MCA), is the commonestvascular lesion for ischemic stroke the Chinese population. We explored the association of geneticpolymorphism and environmental factors in MCA atherosclerosis in the Chinese population. Methods:One hundred fifty-six ischemic stroke patients with MCA stenosis and 181 well-matched ischemicstroke patients without MCA stenosis were examined by polymerase chain reaction (PCR). ThePCR products were analyzed for lipoprotein lipase (LPL) S447X and paraoxonase1 (PON1) Q192Rpolymorphisms by restriction enzyme digestion. Medical history documentation and investigationof biochemical markers were performed for each subject. Results: Univariate analysis showed thatthe levels of systolic blood pressure (SBP) were higher in the MCA stenosis group. There were nosignificant differences in the genotype and allele frequencies of the LPL S447X and PON1 Q192Rpolymorphism observed between the two groups. But, in the patients above 60 years of age with andwithout MCA stenosis, LPL X carriers have higher level of SBP than the LPL SS genotype carriers.Multivariate logistic regression found that SBP was the significant, independent predictor of thepresence of MCA stenosis patients above 60 years of age (P < 0.001, OR=1.206, 95% confidenceintervals: 1.014-1.032).Conclusions: SBP appears to contribute to the pathogenesis of MCA stenosis among Chinese. Thegene polymorphism of LPL S447X may be associated with atherosclerotic MCA stenosis in Chinesepopulation.

BACKGROUNDRecent studies have demonstrated the existence of a small fraction of cells with features of primitive neural progenitor cells and tumor-initiating function in brain tumors. These cells might represent primary therapeutic target for complete eradication of the tumors. This study aimed to determine the resistant phenotype of glioblastoma stem cells (GSCs) to temozolomide (TMZ) and to explore the possible molecular mechanisms underlying TMZ resistance.

METHODSFreshly resected glioblastoma specimen was collected and magnetic isolation of GSCs was carried out using the Miltenyi Biotec CD133 Cell Isolation kit. The cytotoxic effect of TMZ on CD133(+) and CD133(-) glioblastoma cells was determined by using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Autophagy-related proteins (Beclin-1, LC3 and Atg5) and cleaved caspase-3 (p17) were analyzed by Western blotting. Immunofluorescent staining was used to detect Atg5, glial fibrillary acidic protein (GFAP) and CD133 expression in glioblastoma cells. Statistical analysis was carried out using SPSS 10.0 software. For all tests, the level of statistical significance was set at P < 0.05.

RESULTSCD133(+) glioblastoma cells exhibited neurosphere-like growth in vitro and high expression of CD133 stem cell marker. The growth-inhibiting rate in CD133(-) glioblastoma cells treated with 5 or 50 micromol/L TMZ was significantly higher than that in CD133(+) glioblastoma cells ((14.36 +/- 3.75)% vs (2.54 +/- 1.36)% or (25.95 +/- 5.25)% vs (2.72 +/- 1.84)%, respectively, P < 0.05). Atg5, LC3-II and Beclin-1 levels were significantly lower in CD133(+) glioblastoma cells than those in autologous CD133(-) cells after TMZ treatment (P < 0.05). Caspase-3 was mildly activated only in CD133(-) glioblastoma cells after exposure to TMZ (P < 0.05). Immunofluorescent staining revealed elevated expression of Atg5 in GFAP(+) cells following TMZ treatment.

CONCLUSIONSThe GSCs display strong capability of tumor's resistance to TMZ. This resistance is probably contributed by the CD133(+) cells with down-regulation of autophagy-related proteins. Future treatment should target this small population of cancer stem cells in tumors to improve survival of patients.

AC133 Antigen ; Antigens, CD ; metabolism ; Antineoplastic Agents, Alkylating ; therapeutic use ; Apoptosis Regulatory Proteins ; metabolism ; Autophagy-Related Protein 5 ; Beclin-1 ; Blotting, Western ; Caspase 3 ; metabolism ; Cells, Cultured ; Dacarbazine ; analogs & derivatives ; therapeutic use ; Drug Resistance, Neoplasm ; physiology ; Glioblastoma ; drug therapy ; pathology ; Glycoproteins ; metabolism ; Humans ; Immunohistochemistry ; Membrane Proteins ; metabolism ; Microtubule-Associated Proteins ; metabolism ; Peptides ; metabolism

OBJECTIVETo investigate the epigenetic involvement of RASSF1A in intracranial primitive neuroectodermal tumors (PNETs) and compare the methylation patterns between medulloblastoma (MBs) and supratentorial PNETs (SPNETs).

METHODSThe methylation status at the promoter regions of RASSF1A was examined by methylation-specific polymerase chain reaction (MSP) in a cohort of 25 primary MBs, 9 primary SPNETs, 3 MB and 2 SPNET cell lines. RASSF1A-deficient PNET cell lines were treated with 5-aza-2'deoxycytidine, a demethylating agent, to explore the relationship between hypermethylation and the gene expression.

RESULTSThe results revealed no promoter hypermethylation of RASSF1A in 2 normal cerebellar and 5 normal cerebral tissue specimens examined. In contrast, promoter hypermethylation of RASSF1A was detected in 100% (25/25) of primary MBs, 6/9 of primary SPNETs, and all PNET cell lines. These results demonstrated that such epigenetic alteration was tumor-specific. The frequency of hypermethylation of RASSF1A in SPNETs was also found to be significantly lower than that in MBs (Fisher's exact test, P = 0.014). Treatment of RASSF1A-deficient PNET cell lines with 5-aza-2'deoxycytidine restored RASSF1A expression, providing evidence that promoter hypermethylation contributes to transcriptional silencing.

CONCLUSIONSThese results demonstrate that RASSF1A plays an important role in the development of intracranial PNETs. Different hypermethylation status of RASSF1A are found in PNET subtypes suggesting that MBs and SPNETs are epigenetical distinct tumors.

Adolescent ; Adult ; Aged ; Brain Neoplasms ; genetics ; pathology ; Cell Line, Tumor ; Cerebellar Neoplasms ; genetics ; pathology ; Child ; Child, Preschool ; DNA Methylation ; Female ; Gene Expression Regulation, Neoplastic ; Gene Silencing ; HeLa Cells ; Humans ; Infant ; Male ; Medulloblastoma ; genetics ; pathology ; Neuroectodermal Tumors, Primitive ; genetics ; pathology ; Promoter Regions, Genetic ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Suppressor Proteins ; genetics ; Young Adult

Adolescent ; Adult ; Aged ; Cerebellar Neoplasms ; genetics ; Child ; Child, Preschool ; Chromosomes, Human, Pair 16 ; Female ; Humans ; Loss of Heterozygosity ; Male ; Medulloblastoma ; genetics ; Middle Aged

OBJECTIVETo study the genetic alterations of ganglioglioma through the entire genome, and to investigate the pathogenesis of this neoplasm.

METHODSComparative genomic hybridization was used to provide an overview of genetic abnormalities in gangliogliomas.

RESULTSFive cases of gangliogliomas, including 3 males and 2 females, were studied genetically. Loss of genetic materials on the short arm of chromosome 9(9p) was a common genetic alteration found in 3 of 5 cases. Overrepresentation of chromosome 7 was another recurrent chromosomal imbalance, which was further confirmed by fluorescence in situ hybridization. Immunohistochemical analysis was performed on epidermal growth factor receptor (EGFR), which was located on 7p11-p13. All five cases revealed no abnormal expression of EGFR. On the other hand, genetic imbalances were also involved in multiple chromosomes including 2q33-q34, 8q12-q22, 14q21-qter, 15q26-qter and Y.

CONCLUSIONLoss of genetic materials on chromosome 9p and gain on chromosome 7 may be associated with the pathogenesis of this neoplasm.

Adolescent ; Adult ; Brain Neoplasms ; genetics ; metabolism ; Chromosome Aberrations ; Chromosome Deletion ; Chromosomes, Human, Pair 7 ; Chromosomes, Human, Pair 9 ; Female ; Follow-Up Studies ; Ganglioglioma ; genetics ; metabolism ; Humans ; In Situ Hybridization, Fluorescence ; Male ; Nucleic Acid Hybridization ; Receptor, Epidermal Growth Factor ; metabolism

OBJECTIVETo investigate global genetic alterations in medulloblastoma, and to localize critical chromosomal loci with allelic imbalances associated with the development of medulloblastoma.

METHODSA high-resolution genome-wide allelotype analysis, including 384 microsatellite markers, was performed in 12 medulloblastomas.

RESULTSAn average of 238 (62.3%) allelic imbalances were detected on all 39 autosomal arms. Non-random allelic gains or losses were detected on chromosomes 7q (58.3%), 8p (66.7%), 16q (58.3%), 17p (58.3%) and 17q (66.7%). In addition, chromosomal arms with frequencies of allelic imbalances higher than the mean percentage were identified on 3p (33.3%), 3q (33.3%), 4q (41.7%), 7p (33.3%), 8q (41.7%), 10q (41.7%), 13q (33.3%), 14q (33.3%) and 20q (33.3%). No relationship was found between the frequency of allelic imbalances and the clinical outcome of the patients.

CONCLUSIONSA global view of the genetic alterations in medulloblastoma was provided. The allelic imbalances involving chromosomes 7q, 8p, 16q, 17p and 17q may play an important role in the pathogenesis of medulloblastoma.

Adolescent ; Adult ; Alleles ; Allelic Imbalance ; Cerebellar Neoplasms ; genetics ; Child ; Child, Preschool ; Chromosomes, Human, Pair 16 ; Chromosomes, Human, Pair 17 ; Chromosomes, Human, Pair 7 ; Chromosomes, Human, Pair 8 ; Female ; Genotype ; Humans ; Male ; Medulloblastoma ; genetics ; Microsatellite Repeats ; genetics

Adult ; Brain Neoplasms ; genetics ; DNA, Neoplasm ; analysis ; Female ; Genome ; Glioblastoma ; genetics ; Humans ; Loss of Heterozygosity ; Microsatellite Repeats ; Neoplasm Recurrence, Local ; genetics ; Polymerase Chain Reaction

To identify the expression of thrombopoietin (TPO) receptors (c-mpl) on central nervous system (CNS) and to evaluate the role of TPO on neural cell proliferation and protection, immunohistochemical staining, RT-PCR, MTT, and annexin-V methods were used in this study. The results showed the expression of TPO receptor on human CNS and murine neural cells. C-mpl mRNA was identified in human cerebral hemispheres and cerebellum, and mouse neural cell line C17.2 by RT-PCR. C-mpl was also confirmed in human cerebral hemispheres by immunohistostaining with con-focal microscopy. Furthermore, TPO had a stimulating effect on the growth of in vitro neural cell C17.2 by MTT assay. The anti-apoptotic effect of TPO on C17.2 cells was also demonstrated by staining with annexin-V and PI. In conclusion, the first evidence showed the expression of TPO receptor c-mpl in central nervous system. Moreover, the effect of TPO on neural cell proliferation and anti-apoptosis was also demonstrated on in vitro neural cells.
Animals ; Apoptosis ; drug effects ; Brain Chemistry ; Cell Line ; Cell Proliferation ; drug effects ; Erythropoietin ; pharmacology ; Humans ; Mice ; Neoplasm Proteins ; analysis ; Neurons ; drug effects ; Oncogene Proteins ; analysis ; Proto-Oncogene Proteins ; analysis ; Receptors, Cytokine ; analysis ; Receptors, Thrombopoietin ; Thrombopoietin ; pharmacology

OBJECTIVETo investigate molecular genetic alterations associated with primary and corresponding recurrent glioblastoma multiforme(GBM) and to identify which chromosomal regions of the whole genome may be involved in the recurrence of primary GBM.

METHODSA high-resolution allelotyping study of one patient's primary GBM and corresponding recurrent GBM was performed by PCR-based loss of heterozygosity(LOH) analysis with the use of 382 fluorescent dye-labeled polymorphic microsatellite markers covering all 22 autosomes. The mean genetic distance between two flanking markers is 10 cM.

RESULTSLOH at locus D9S157 on 9p21 and at loci D10S537, D10S185, D10S192, D10S597, D10S587, D10S217 on 10q21.3-26.3 was observed in the primary GBM. As for corresponding recurrent tumor, LOH was observed not only in expanded regions on 9p21 and 10q21.3-26.3 but also on multiple other chromosomal arms, including 1q, 7p,7q, 21q, 20p, 20q, 10p, 19p, 19q.

CONCLUSIONChromosome 9p and 10q may be involved in the development of this GBM. Although histopathological diagnoses of the primary and corresponding recurrent tumor are identical, the recurrence of GBM is characterized by an increased involvement of molecular genetic abnormalities and may be accompanied by inactivation of more tumor suppressor genes.

Adult ; Alleles ; Chromosome Mapping ; methods ; Chromosomes, Human, Pair 1 ; genetics ; Chromosomes, Human, Pair 10 ; genetics ; Chromosomes, Human, Pair 19 ; genetics ; Chromosomes, Human, Pair 20 ; genetics ; Chromosomes, Human, Pair 21 ; genetics ; Chromosomes, Human, Pair 7 ; genetics ; Chromosomes, Human, Pair 9 ; genetics ; DNA ; genetics ; Female ; Glioblastoma ; genetics ; pathology ; surgery ; Humans ; Loss of Heterozygosity ; Microsatellite Repeats ; Neoplasm Recurrence, Local

OBJECTIVETo study the mechanism of antisense epidermal growth factor receptor cDNA in growth suppression of glioblastomas cells.

METHODSGlioblastoma U87MG cells, which over-express epidermal growth factor receptor (EGFR), were transfected with antisense-EGFR constructs. Several clones with stable expression of lower or undetectable levels of EGFR protein were obtained. The effect of antisense-EGFR on cell differentiation was studied using morphological evaluation and western blotting analysis of glial fibrillary acidic protein (GFAP) expression. The effect of antisense-EGFR on cell cycle was studied by flow cytometry and immunohistochemical analysis of p53, Rb, p16 and CDK4 expressions. The effect of antisense-EGFR on telomerase activity was studied by telomeric repeat amplification protocol (TRAP) assay.

RESULTSU87MG cells that were transfected with antisense-EGFR constructs had smaller cell bodies and longer processes, and expressed higher level of GFAP compared with that of the control cells. Flow cytometric analysis showed that the proportion of cells in G(0)/G(1) phases of the cell cycle in the antisense EGFR cDNA transfected clones increased significantly when compared with control cells, whereas the proportion of cells in S phase decreased markedly. In addition, immunohistochemical analysis showed that the expression of wild-type p53 was significantly increased in the antisense-EGFR cDNA transfected clones, whereas the expressions of Rb, p16 and CDK4 were not altered. TRAP assay revealed that telomerase activity in the antisense-EGFR clones was significantly decreased.

CONCLUSIONSAntisense-EGFR transfection inhibits U87MG cell growth by inducing cell differentiation and p53 expression, G(1) cell cycle arrest and inhibition of telomerase activity.

Cell Line, Tumor ; DNA, Antisense ; therapeutic use ; DNA, Complementary ; therapeutic use ; Flow Cytometry ; Glioblastoma ; chemistry ; drug therapy ; pathology ; Humans ; Immunohistochemistry ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; genetics ; Retinoblastoma Protein ; analysis ; Transfection ; Tumor Suppressor Protein p53 ; analysis