Human Brain Glioma Research Articles

MiR-124 radiosensitizes human glioma cells by targeting CDK4

The aberrant expression of cyclin-dependent kinase-4 (CDK4) has previously been observed in human brain glioma. Furthermore, it is observed that up-regulation of CDK4 is associated with therapy resistance and relapse. However, the mechanisms behind these phenomena remain unclear. Here, we demonstrated that elevated CDK4 expression is correlated with poor prognosis in glioma after radiotherapy and that CDK4 knockdown conferred radiosensitivity in glioma cell lines. CDK4 was identified as potential downstream target of miR-124 through bioinformatics analysis and dual-firefly luciferase reporter assay. Furthermore, restoration of miR-124 could confer radiosensitivity. Cell differentiation agent-2 (CDA-2) mimicked the effect of miR-124 restoration and CDK4 knockdown, and sensitized xenografts to radiation in an animal model. Our findings demonstrated for the first time that CDK4 was a downstream target of miR-124 and that CDA-2 could radiosensitize Glioblastoma multiforme cells through the MiR-124-CDK4 axis.

Significance and expression of integrin .BETA.1 and matrix metalloproteinase-9 in human brain glioma

Objective To investigate the expression of integrin β1 and matrix metalloproteinase-9 (MMP-9) and their significances in human brain glioma.Methods The expression levels of Integrin β1 and MMP-9 in 50 cases of human brain glioma tissues and 20 cases of normal brain tissues were detected by using immunohistochemical method.Results The expression rate of Integrin β1 was 42％ (21/50) in brain glioma tissues,and 15％ (3/20) in normal brain tissues (P ＜ 0.01),the expression rate of MMP-9 was 72％ (36/50) in brain glioma tissues,and 15％ (3/20) in normal brain tissues (P ＜0.01).the expressions of Integrin β1 and MMP-9 were related to histological grades of glioma (P ＜0.05),the expressions of Integrin β1 was correlated positively with the expressions level of MMP-9 (r =0.35,P ＜ 0.05).Conclusion The expression of Integrin β1 and MMP-9 are closely correlated with the onset,progression and metastasis of brain glioma. Key words: Immunohistochemical method; Integrin β1; Matrix metalloproteinase-9; Glioma

RNA interference-mediated USP22 gene silencing promotes human brain glioma apoptosis and induces cell cycle arrest.

Ubiquitin-specific protease 22 (USP22) is a novel tumor stem cell marker that plays a key role in tumorigenesis and cell cycle progression. However, the effect of silencing the USP22 gene on human brain glioma cell growth is not well understood. In the present study, high gene expression of USP22 was identified in human brain glioma cells. In addition, RNA interference technology was used to silence USP22 gene expression in human brain glioma cells. Silencing the USP22 gene was found to effectively inhibit proliferation of human brain glioma cells, resulting in cell apoptosis and cell cycle arrest at the G2/M phase. USP22 silencing was also found to lead to reduced expression of cell cycle proteins, including CDK1, CDK2 and CyclinB1. In summary, in this study the USP22 gene was demonstrated to play a key regulatory role in the growth of human brain glioma cells by affecting progression of apoptosis and the cell cycle.

Poly(amido amine) is an ideal carrier of miR-7 for enhancing gene silencing effects on the EGFR pathway in U251 glioma cells

microRNAs are regarded as promising drugs for glioma gene therapy. However, conventional administration routes, such as oral administration and intravenous infusion, present low efficiency due to the blood-brain barrier and intercellular retention, thereby limiting their application. Recent studies showed poly(amido amine) (PAMAM) was a candidate carrier due to its high solubilization, delayed release and low toxicity. In the present study, U251 human brain glioma cells were transfected with the miR-7 gene using PAMAM as the vector to determine the transfection efficiency and therapeutic effects invivo and invitro. We found that PAMAM exhibited higher transfection efficiency and longer duration of action compared with liposome delivery, and miR-7 efficiently silenced some genes involved in the epidermal growth factor receptor (EGFR) pathway and achieved favorable effects in treating glioma invivo and invitro. These investigations provide a basis for developing high-efficiency micromolecular drug delivery.

Relationship of 14-3-3zeta (ζ), HIF-1α, and VEGF expression in human brain gliomas

Accumulating evidence suggests that tissue hypoxia and apoptosis play important roles in the malignant progression of brain tumors. We investigated the relationship of 14-3-3zeta (an apoptosis-related protein), HIF-1α, and VEGF immunohistochemistry, and evaluated the prognostic value of their expression in human brain gliomas. A semiquantitative analysis of the immunoreactivity scores (IRSs) of the 14-3-3zeta, HIF-1α, and VEGF proteins was performed in 27 patients with various grades of gliomas. The IRS of 14-3-3zeta increased with tumor grade, with grade IV gliomas having the highest score (P<0.05). Similar results were found for the IRSs of HIF-1α and VEGF (P<0.05). A significant positive correlation was found between the IRSs of 14-3-3zeta and HIF-1α, 14-3-3zeta and VEGF, and HIF-1α and VEGF (P<0.001 for all). The survival time of HIF-1α in grade III and grade IV glioma patients with low IRSs (0-6) was significantly longer than that in such glioma patients with high IRSs (8-12) (P<0.05). These data indicate that 14-3-3zeta, HIF-1α, and VEGF are involved in the same cascade of the malignant progression of gliomas. Further studies will elucidate their detailed role in the malignant progression of glioma, and will contribute to the development of a new treatment strategy for this lethal disease.

Chemo-enzymatic Synthesis of Propionyl-ester-linked Taxol-monosaccharide Conjugate and its Drug Delivery System Using Hybrid-Bio-nanocapsules Targeting Brain Glioma Cells

Taxol is recognized as one of the most potent anticancer agents used in the treatment of breast and ovarian cancers, which are common cancers in women. To overcome its shortcomings, that is, its low water-solubility that reduces drug loading capacity of DDS carriers when incorporating taxol, chemo-enzymatic synthesis of ester-linked taxol-glucose conjugate, i.e., 7-propionyltaxol 2″-O-α-D-glucoside, as a water soluble taxol prodrug was achieved by using a-glucosidase as a glucosylation catalyst. The water-solubility of 7-propionyltaxol 2″-O-α-D-glucoside (25 mM) was 63 fold higher than that of taxol (0.4 mM). The pre-S1 peptide which displays on the surface of bio-nanocapsules, which are nanoparticles composed of the hepatitis B virus surface antigen, was replaced with the antibody affinity motif of protein A. Conjugation of such bio-nanocapsules with anti-human epidermal growth factor receptor antibody gave hybrid bio-nanocapsules. The hybrid bio-nanocapsules were effective for delivering 7-propionyltaxol 2″-O-α-D-glucoside to human brain glioma cells. 7-Propionyltaxol 2″-O-α-D-glucoside was effectively hydrolyzed to give taxol in 95% by human glioma cells. The drug loading capacity of hybrid bio-nanocapsules incorporating 7-propionyltaxol 2″-O-α-D-glucoside was 120 times higher than that incorporating taxol itself.

Inhibition of xenograft human glioma tumor growth by lentivirus-mediated gene transfer of alphastatin

Angiogenesis is crucial for the development and metastasis of human brain glioma. Based on our previous successful construction of a lentivirus-mediated alphastatin (an endogenous angiogenesis inhibitor) gene transfer system and our findings that alphastatin exhibited potent inhibitory effects on the migration and differentiation of human umbilical vein endothelial cell lines (HUVECs) induced by vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) invitro, here, we investigated the effect of using lentiviral vectors to overexpress alphastatin in human glioma cells to show whether sustained long-term expression of alphastatin diminishes tumor growth in a xenograft glioma model. We found that the transduced glioma cells sustainedly secreted alphastatin, which did not affect the proliferative ability of the glioma cells. Furthermore, tumor xenografts treated with the recombinant lentivirus were significantly smaller compared to the control xenografts and vascularity within the treated tumors was evidently decreased. Our data suggest that stable expression of alphastatin inhibits human glioma growth by inhibiting angiogenesis, with a probable mechanism of suppressing the turnover of VE-cadherin membrane molecules.

Evaluation of 3′-deoxy-3′-[18F]-fluorothymidine (18F-FLT) kinetics correlated with thymidine kinase-1 expression and cell proliferation in newly diagnosed gliomas

The thymidine analog 3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) has been developed as a positron emission tomography (PET) tracer to assess the proliferation activity of tumors in vivo. The present study investigated the relationship between the kinetic parameters of (18)F-FLT in vivo and thymidine kinase-1 (TK-1) expression and cell proliferation rate in vitro, and blood-brain barrier (BBB) breakdown in human brain gliomas. A total of 21 patients with newly diagnosed gliomas were examined by (18)F-FLT PET kinetic analysis. Maximum standardized uptake value (SUVmax) and tumor-to-normal (T/N) ratio of (18)F-FLT in the tumor and (18)F-FLT kinetic parameters in the corresponding contralateral region were determined. The expression levels of TK-1 protein and mRNA were determined by immunohistochemistry (IHC) and real-time polymerase chain reaction (PCR), respectively, using surgical specimens. The cell proliferation rate of the tumor was determined in terms of the Ki-67 labeling index. BBB breakdown was evaluated on MR images with contrast enhancement. (18)F-FLT SUVmax and T/N ratio were significantly correlated with the influx rate constant (K (1); P = 0.001 and P < 0.001, respectively), but not with the phosphorylation rate constant (k (3)). IHC and real-time PCR studies demonstrated a significant correlation between K (1) and TK-1 mRNA expression (P = 0.001), but not between k (3) and TK-1 protein and mRNA expression. Linear regression analysis revealed a significant correlation between K (1) and the Ki-67 index (P = 0.003), but not between k (3) and the Ki-67 index. TK-1 mRNA expression was significantly correlated with the Ki-67 index (P = 0.009). (18)F-FLT SUVmax and T/N ratio were significantly correlated with BBB breakdown evaluated by contrast enhancement in MR images (P = 0.003 and P = 0.011, respectively). These results indicate that (18)F-FLT uptake in the tumor is significantly related to transport through the disrupted BBB, but not through phosphorylation activity. Although the tissue TK-1 expression reflects tumor proliferation activity, the phosphorylation rate constant k (3) determined by (18)F-FLT PET kinetic analysis does not accurately reflect TK-1 expression in the tissue and should not be used as a surrogate biomarker of cell proliferation activity in human brain gliomas.

Compartment- and malignance-dependent up-regulation of γ-glutamyltranspeptidase and dipetidylpeptidase-IV activity in human brain gliomas.

γ-Glutamyltranspeptidase (GGT, syn. γ-Glutamyltransferase) and dipeptidylpeptidase-IV (DPP-IV) activity participates in metabolic and growth control of normal and tumor cells by processing biologically active peptides. Here, we report on up-regulation of these enzymes in human brain gliomas determined by catalytic enzyme histochemistry and immunocytochemistry. Higher activity of GGT was found in 50%, 68% and 81% of WHO grade II, III and IV tumors, respectively. The process started at/near the microvasculature, from where it spread to the parenchyma. On average, the enzyme activity in grade II, III and IV gliomas exceeded controls 2.0, 3.0 and 3.5-fold, respectively. Up-regulation of DPP-IV-like activity also started at the microvasculature, but mainly in pericytes and mononuclear-like cells around the vessels and dispersed in the parenchyma. Marked elevation of this enzyme activity, comprising also tumor parenchyma, occurred only in grade IV glioblastomas (65% patients; 3.6 times above controls) which can, therefore, help in their differentiation from grade III gliomas. The increase of total DPP-IV-like activity also included its two enzymatic homologs, the canonical DPP-IV/CD26 and FAP-1α. The increase in GGT is supposed to be a tumor grade dependent response of microvasculature and tumor astrocytes to stress induced by tissue hypoxia and/or the metabolic aberrancies. The increase in DPP-IV-like activity in high-grade tumors can be attributed to inflammatory/scavenging processes performed by the mononuclear-like cells and, in glioblastomas, also to regressive changes in the structure and function of the microvasculature and tumor parenchyma, including astrocyte stress response. The inverse relationship between DPP-IV-like activity and Ki67 in most glioblastomas and shorter survival time of patients with low activity of this enzyme also suggest its anti-oncogenic effects.

Mda-9/syntenin Promotes Human Brain Glioma Migration through Focal Adhesion Kinase (FAK)-JNK and FAK-AKT Signaling

Invasion is usually recognized as the main reason for the high recurrence and death rates of glioma and restricts the efficacy of surgery and other therapies. Therefore, we aimed to investigate the mechanism involved in promotion effects of mda-9/syntenin on human glioma cell migration. The wound healing method was used to test the migration ability of human glioma cells CHG-5 and CHG-hS, stably overexpressing mda-9/syntenin. Western blotting was performed to determine the expression and phosphorylation of focal adhesion kinase (FAK) and JNK in CHG-5 and CHG-hS cells. The migration ability of CHG-hS cells was significantly higher than that of CHG-5 cells in fibronectin (FN)-coated culture plates. Phosphorylation of FAK on tyrosine 397, 576, and 925 sites was increased with time elapsed in CHG-hS cells. However, phosphorylated FAK on the tyrosine 861 site was not changed. Phosphorylated Src, JNK and Akt levels in CHG-hS cells were also significantly upregulated. Phosphorylation of JNK and Akt were abolished by the specific inhibitors SP600125 and LY294002, respectively. and the migration ability of CHG-hS cells was decreased, indicating that the JNK and PI3K/Akt pathways play important roles in regulating mda-9/syntenin-induced human brain glioma migration. Our results indicate Mda- 9/syntenin overexpression could activate FAK-JNK and FAK-Akt signaling and then enhance the migration capacity of human brain glioma cells.

MicroRNA-34a inhibits human brain glioma cell growth by down-regulation of notch1

The effects of microRNA-34a (miR-34a)-regulated Notch1 gene on the proliferation and apoptosis of the human glioma cell line U87 were investigated in this study. The U87 cells were divided into miR-34a mimics, negative control, mock transfection and blank control groups in terms of different treatments. In miR-34a mimics group, human U87 glioma cells were transfected with miR-34a mimics by using lipofectamine 2000. The cells transfected with nonsense microRNA were set up as negative control group. Those treated with lipofectamine 2000 only were designated to the mock tranfection group. In the blank control group, the cells were cultured routinely and no treatment was given. The expression of miR-34a and Notch1 was detected by using real-time RT-PCR. Western blotting was employed to monitor the change in Notch1 protein. Cell proliferation and apoptosis were measured by CCK-8 and flow cytometry. The results showed that the proliferative ability of U87 cells was significantly reduced and the apoptotic cells increased in miR-34a mimics group relative to control groups. The expression of miR-34a was significantly up-regulated in mimics group as compared with control groups (P<0.05). Furthermore, Notch1 protein levels were significantly decreased in miR-34a mimics group when compared with control groups (P<0.05), but the mRNA expression of Notch1 showed no significant difference among these groups. It was concluded that miR-34a may suppress the proliferation and induce apoptosis of U87 cells by decreasing the expression of target gene Notch1, suggesting that miR-34a may become a promising gene therapeutic target for brain glioma.

Isolation, cultivation and identification of brain glioma stem cells by magnetic bead sorting.

This study describes a detailed process for obtaining brain glioma stem cells from freshly dissected human brain glioma samples using an immunomagnetic bead technique combined with serum-free media pressure screening. Furthermore, the proliferation, differentiation and self-renewal biological features of brain glioma stem cells were identified. Results showed that a small number of CD133 positive tumor cells isolated from brain glioma samples survived as a cell suspension in serum-free media and proliferated. Subcultured CD133 positive cells maintained a potent self-renewal and proliferative ability, and expressed the stem cell-specific markers CD133 and nestin. After incubation with fetal bovine serum, the number of glial fibrillary acidic protein and microtubule associated protein 2 positive cells increased significantly, indicating that the cultured brain glioma stem cells can differentiate into astrocytes and neurons. Western blot analysis showed that tumor suppressor phosphatase and tensin homolog was highly expressed in tumor spheres compared with the differentiated tumor cells. These experimental findings indicate that the immunomagnetic beads technique is a useful method to obtain brain glioma stem cells from human brain tumors.

Expression of transforming growth factor-β1 (TGF-β1) and E-cadherin in glioma

Gliomas are the most common tumors in the central nervous system. This study aims to investigate the expressions of transforming growth factor-β1 (TGF-β1) and epithelial cadherin (E-cadherin) in human brain glioma tissues and the correlation between their expressions with clinical pathological features and clinical significance. The expressions of mRNA or protein of TGF-β1 and E-cadherin were detected by using reverse transcription polymerase chain reaction (RT-PCR) and Western blot in these tissues. Positive rates of the expression of TGF-β1 and E-cadherin were 62.9 % and 38.6 % in brain tissues of glioma patients. The expressions of mRNA or protein for TGF-β1 in brain glioma tissues were significantly higher than that in normal brain tissues (p < 0.01). Their expressions in well-differentiated glioma brain tissues were lower than those in poorly differentiated glioma brain tissues (p < 0.01). A negative correlation was found between TGF-β1 and E-cadherin in brain glioma tissues (r = -0.302, p < 0.011). The cell numbers of C6 glioma through Transwell chambers were decreased significantly (p < 0.01), and the expression of TGF-β1 was downregulated significantly (p < 0.01). However, the expression of E-cadherin was upregulated significantly (p < 0.01) after transfecting TGF-β1 siRNA. The expression changes of TGF-β1 and E-cadherin may be related to the emergence and the development of glioma. Downregulation of TGF-β1 expression using siRNA can decrease the invasive capability of C6 glioma cells.

Steroidal saponins from Fritillaria pallidiflora Schrenk

Five new steroidal saponins, Pallidifloside D (1), Pallidifloside E (2), Pallidifloside G (5), Pallidifloside H (6) and Pallidifloside I (7), together with seven other steroidal saponins (3, 4, 8–12) were isolated from the dry bulbs of Fritillaria pallidiflora Schrenk. Their structures were established by spectroscopic techniques (IR, MS, 1D and 2D NMR) and chemical means. The isolated steroidal saponins were evaluated for cyotoxic activity against human C6 brain gliomas and Hela cervix cancer cell lines using MTT assays. Compounds 1, 10, 11, 12 showed cytotoxicity against C6 and Hela cell lines with IC50 values in the range of 5.1–75.8μM.

Relation of LAT1/4F2hc expression with pathological grade, proliferation and angiogenesis in human gliomas

BackgroundLAT1/4F2hc heterodimeric complex is a major route for the transport of large neutral essential amino acids through the plasma membrane. Although it has been shown that LAT1/4F2hc is highly expressed in a variety of human tumors including gliomas, and LAT1 over-expression is associated with glioma grade and poor prognosis of glioma patients, the precise tissue location of LAT1/4F2hc in gliomas and the precise role of LAT1/4F2hc in glioma biological features remain unclear.MethodsIn the current study, the expressions of LAT1, 4F2hc, CD34 and Ki-67 were investigated by immunohistochemistry in 62 cases of human brain glioma; LAT1/4F2hc expression level, Ki-67 labeling index (Ki-67 LI) and microvessel density (MVD) were measured semi-quantitatively; and the correlation of LAT1/4F2hc expression with histopathological features, Ki-67 LI and MVD in gliomas was further analyzed.ResultsThe results showed that both LAT1 and 4F2hc were expressed in all examined specimens. LAT1 but 4F2hc expression levels significantly correlated with the pathological grade and both expression levels significantly correlated with Ki-67 LI of gliomas. We also demonstrated that both LAT1 and 4F2hc immunoreactivity were observed in tumor cells as well as vascular endothelia; furthermore, the LAT1 expression level was markedly associated with glioma MVD as well.ConclusionLAT1/4F2hc over-expression is closely correlates with the malignant phenotype and proliferation of gliomas, and LAT1 was associates with glioma angiogenesis. LAT1/4F2hc, especially LAT1, may become a novel potential molecular target for glioma biological therapy.

Expression levels of Fas/Fas-L mRNA in human brain glioma stem cells

Despite advancements in research made over the past decades, the prognosis of gliomas remains dismal. Fas/Fas ligand (Fas-L)-related immunotherapy may be regarded as a treatment of choice as it can induce the apoptosis of glioma cells, and has shown promising results in experimental studies. Over the years, brain glioma stem cells (BGSCs) have been accepted as the origin of gliomas and determine their biological features. The theory of BGSCs has facilitated the study of gliomas. In this study, we conducted a series of assays to culture BGSCs from clinical samples and determined the mRNA expression levels of Fas/Fas-L in BGSCs. We also investigated the effects of Fas/Fas-L-related immunotherapy on the apoptosis of glioma cells. BGSCs were grown from samples of 8 patients suffering from gliomas and identified by the assessment of biological characteristics and immunocytochemistry. Total RNA was extracted and reverse-transcribed into cDNA, and the expression levels of Fas/Fas-L mRNA were determined by real-time RT-PCR, followed by statistical analysis. The results showed that the Fas and Fas-L mRNA expression levels in BGSCs were lower compared to those in primary cultured glioma cells, which were statistically significant (P<0.001). These results indicate that immunotherapy involving Fas/Fas-L may not eradicate the BGSCs, which would result in the relapse of glioma. However, further research is required to investigate the mechanisms involved and define the prospect of Fas-involved immunotherapy against gliomas.

Granulocyte–macrophage colony-stimulating factor as an autocrine survival-growth factor in human gliomas

We studied the expression of granulocyte–macrophage colony-stimulating factor (GM-CSF) and its receptors (GM-CSF.R) in 20 human brain gliomas with different tumor gradings and demonstrated constitutive high levels of both mRNA gene expression and protein production exclusively in the highest-grade tumors (WHO, III–IV grade). Five astrocytic cell lines were isolated in vitro from glioma cells, which had selectively adhered to plates pre-coated with rhGM-CSF. These cells were tumorigenic when xenografted to athymic mice, and produced GM-CSF constitutively in culture. Two lines, particularly lines AS1 and PG1, each from a patient with glioblastoma multiforme, constitutively over-expressed both GM-CSF and GM-CSF.R genes and secreted into their culture media biologically active GM-CSF. Different clones of the AS1 line, isolated after subsequent passages in vitro and then transplanted to athymic mice, demonstrated higher tumorigenic capacity with increasing passages in vivo. Cell proliferation was stimulated by rhGM-CSF in late-stage malignant clones, whereas apoptosis occurred at high frequency in the presence of blocking anti-GM-CSF antibodies. In contrast, rhGM-CSF did not induce any apparent effect in early-stage clones expressing neither GM-CSF nor GM-CSF.R. The addition of rhGM-CSF or rhIL-1β, to cultures induced the overproduction of both GM-CSF and its receptors and increased gene activation for several functional proteins (e.g. NGF, VEGF, VEGF.R1, G-CSF, MHC-II), indicating that these cells may undergo dynamic changes in response to environmental stimuli. These findings thus revealed: (1) that the co-expression of both autocrine GM-CSF and GM-CSF.R correlates with the advanced tumor stage; (2) that an important contribution of GM-CSF in malignant glioma cells is the prevention of apoptosis. These results imply that GM-CSF has an effective role in the evolution and pathogenesis of gliomas.

Human brain glioma stem cells are more invasive than their differentiated progeny cells in vitro

Glioma, the most commonly occurring primary intracranial tumor, remains associated with a dismal outcome, despite the availability of multimodal therapies. Recently, however, the identification of brain glioma stem cells (BGSC) has opened up new avenues for research. BGSC are now accepted as the progenitor cells of gliomas and are thought to determine the biological features of the resulting tumors. Thus, the diffuse invasiveness of gliomas should also be theoretically driven by BGSC. However, little research effort has been directed at understanding the invasiveness of BGSC. In the present study, BGSC from eight surgical glioma specimens were cultured and identified. Using Matrigel invasion assays, the invasiveness of these cells was measured and compared with that of their respective differentiated progeny cells in vitro. For all eight clinical specimens, the BGSC were significantly more invasive than their differentiated progeny cells. These findings indicate a key role for BGSC in glioma infiltration and invasion. We also found that BGSC tended to aggregate and reform into new spheres after travelling into the Matrigel, preserving some of the morphological characteristics of the suspended cells. The invasiveness of the BGSC did not correlate with the pathological grade of glioma in the present study, so further investigations using larger sample sizes are needed to better understand the mechanisms underlying the invasiveness of BGSC.

Effects of adriamycin and bone morhogenetic proteins 4 in human brain glioma cell line U251 and probable signal pathway

Objective To investigate the effects of bone morhogenetic proteins 4 （BMP4） and the probable signal pathway in human brain glioma cell line U251.Method Adriamycin or plasmid of BMP4 was given to U251 cells and BMP4 siRNA was given to U251 cells which had been given adriamycin for 48 h.MTT was used to detect the activity of U251 cell growth in control group and treatment group,the formula（ 1 -treatment group OD/control group OD） × 100% was used to calculate U251 cells growth inhibition rate. Reverse transcription - PCR （ RT - PCR ）, fluorescence quantitative PCR （ FQ - PCR ） and Western blot were used to observe whether the translation was sucessful as well as the expression of BMP4 and mothers against decapentaplegic homolog 4 （ SMAD4 ）.Results Compared to control group, U251 cells were inhibited when adriamycin or plasmid of BMP4 was given to U251 cells.The expression of BMP4 was up -regulated and SMAD4was down-regulated.Compared to the adriamycin group,the cells inhibition was increased when BMP4 siRNA was given to adriamycin -treated U251 cells for 48 h.The expression of BMP4 was decreased and the SMAD4 was increased.Conclusions Adriamycin could inhibit U251 cells.BMP4 is associated with the inhibition of U251cells through BMP4 - Smad signal pathway.BMP4 may be a new target for glioma therapy. Key words: Glioma; Bone morphogenetic protein 4; SMAD4; Target therapy; U251

Expressions of matrix metalloproteinase-7 and matrix metalloproteinase-14 associated with the activation of extracellular signal-regulated kinase1/2 in human brain gliomas of different pathological grades

The purpose of this study is to determine whether the expressions of MMP-7 and MMP-14 are associated with the ERK 1/2 signaling pathway in human brain gliomas of different pathological grades. Immunohistochemistry and western blot methods were used to determine the expressions of MMP-7, MMP-14 and the phosphorylation status of ERK1/2 in 73 cases of human brain glioma specimens and two cases of normal brain tissues. Results indicated that the protein expression levels of MMP-7, MMP-14 and ERK1/2 phosphorylation level were all elevated with the increasing pathological grades in brain glioma tissues, and correlation assay indicated that the level of ERK1/2 phosphorylation was positively correlated with protein expression levels of MMP-7 and MMP-14 in gliomas of different pathological grades respectively. Moreover, the impact of ERK1/2 inhibitor U0126 on the expressions of MMP-7 and MMP-14 was examined in human U87 glioma cells by western blot analysis. The expressions of MMP-7 and MMP-14 were significantly decreased in human U87 glioma cells after treatment with ERK1/2 inhibitor U0126. The above results suggest that the expressions of MMP-7 and MMP-14 may be associated with activation of ERK1/2 signaling pathway in human brain gliomas of different pathological grades.