Cooperative function of Chk1 and p38 pathways in activating G2 arrest following exposure to temozolomide

2004 ◽  
Vol 100 (6) ◽  
pp. 1060-1065 ◽  
Author(s):  
Yuichi Hirose ◽  
Makoto Katayama ◽  
Mitchel S. Berger ◽  
Russell O. Pieper
Keyword(s):  
Glioma Cells ◽  
Mitogen Activated Protein Kinase ◽  
Human Glioma Cells ◽  
G2 Arrest ◽  
Content Type ◽  
P38 Inhibitor ◽  
Mitogen Activated Protein ◽  
Chk1 Inhibitor ◽  
Fine Print ◽  
P38 Pathway

Object. The Chk1 and p38 mitogen-activated protein kinase (MAPK) pathways play key roles in the G2 arrest caused by exposing glioma cells to temozolomide (TMZ). Although inhibition of either pathway sensitizes glioma cells to TMZ-induced cytotoxicity, the relative contributions of these pathways to TMZ-induced G2 arrest and to TMZ resistance conferred by G2 arrest have not been defined. Methods. The authors pharmacologically inhibited the Chk1 and/or p38 pathways in U87MG human glioma cells prior to and/or after exposure to TMZ; thereafter, effects on the TMZ-induced G2 arrest pathway and toxicity were monitored. The p38 inhibitor SB203580 or the Chk1 inhibitor UCN-01 or their combination blocked TMZ-mediated inactivation of cdc25C and cdc2, suggesting that p38 and Chk1 pathways work cooperatively and are both necessary to inactivate cdc25C and cdc2. Consistent with this idea, the inhibition of both Chk1 and p38 pathways did not lead to greater bypass of TMZ-induced G2 arrest or greater cytotoxicity than inhibition of either pathway alone. Inhibition of p38 did not alter TMZ-induced Chk1 activation/phosphorylation and vice versa, suggesting that p38 and Chk1 do not cooperatively bring about G2 arrest by reciprocal activation/phosphorylation. The two pathways, however, are not functionally identical; the Chk1 pathway was required for both the initiation and maintenance of TMZ-induced G2 arrest, whereas the p38 pathway played a role only in the initiation. Conclusions. The Chk1 and p38 pathways cooperate to bring about TMZ-induced G2 arrest, and the inhibition of either pathway alone is sufficient to sensitize U87MG glioma cells to TMZ-induced cytotoxicity.

Differential effects of vincristine and phenytoin on the proliferation, migration, and invasion of human glioma cell lines

1995 ◽  
Vol 82 (6) ◽  
pp. 1035-1043 ◽  
Author(s):  
Jörg-Christian Tonn ◽  
Hans Kristian Haugland ◽  
Jaakko Saraste ◽  
Klaus Roosen ◽  
Ole Didrik Laerum
Keyword(s):  
Cell Lines ◽  
Glioma Cell ◽  
Glioma Cells ◽  
Migration And Invasion ◽  
Human Glioma ◽  
Human Glioma Cells ◽  
Content Type ◽  
Glioma Cell Lines ◽  
Dose Dependent ◽  
Fine Print

✓ The aim of this study was to investigate the antimigratory and antiinvasive potential of vincristine sulfate (VCR) on human glioma cells and to analyze whether phenytoin (5,5-diphenylhydantoin; DPH) might act synergistically with VCR. Vincristine affects the cytoplasmic microtubules; DPH has been reported to enhance VCR cytotoxicity in murine cells. In two human glioma cell lines, GaMG and D-37MG, we found VCR to reduce monolayer growth and colony formation in a dose-dependent fashion at concentrations of 10 ng/ml and above. Phenytoin increased the cytotoxic and cystostatic effects of VCR in monolayer cells but not in spheroids. Multicellular spheroids were used to investigate directional migration. A coculture system of GaMG and D-37MG spheroids with fetal rat brain aggregates was used to analyze and quantify tumor cell invasion. A dose-dependent inhibition of migration and invasion by VCR was observed in both cell lines without further enhancement by DPH. Immunofluorescence microscopy with antibodies against α-tubulin revealed dose-dependent morphological alterations in the microtubules when the cells were exposed to VCR but not after incubation with DPH. Based on the combination of standardized in vitro model systems currently in use and the present data, the authors strongly suggest that VCR inhibits migration and invasion of human glioma cells. This is not altered by DPH, which inhibits cell proliferation in combination with VCR.

Mitogen-activated protein kinase mediation of hemolysate-induced contraction in rabbit basilar artery

1999 ◽  
Vol 90 (6) ◽  
pp. 1091-1097 ◽  
Author(s):  
Alexander Y. Zubkov ◽  
Kotaro Ogihara ◽  
Phani Tumu ◽  
Anita Patlolla ◽  
Adam I. Lewis ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Basilar Artery ◽  
Kinase Inhibitor ◽  
Contractile Response ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Western Blots ◽  
Content Type ◽  
Mitogen Activated Protein ◽  
Fine Print

Object. Mitogen-activated protein kinase (MAPK) is an important signaling factor in vascular proliferation and contraction, which are the two features of cerebral vasospasm that follow subarachnoid hemorrhage. The authors studied the possible involvement of MAPK in hemolysate-induced signal transduction and contraction in rabbit basilar artery (BA).Methods. Isometric tension was used to record the contractile response of rabbit BA to hemolysate, and Western blots were obtained using antibodies for MAPK.The following results are reported. 1) Hemolysate produced a concentration-dependent contraction of rabbit BA; however, preincubation of arteries with the MAPK kinase (MEK) inhibitor PD-98059 markedly reduced this contraction. The administration of PD-98059 also relaxed, in a concentration-dependent fashion, the sustained contraction induced by 10% hemolysate. 2) The Janus tyrosine kinase 2 inhibitor AG-490, preincubated with arterial rings, reduced the contractile response to hemolysate but failed to relax the sustained contraction induced by this agent. The Src-tyrosine kinase inhibitor damnacanthal and the phosphatidylinositol 3—kinase inhibitor wortmannin failed to reduce hemolysate-induced contraction. 3) Hemolysate produced a time-dependent elevation of MAPK immunoreactivity as seen on Western blots of rabbit BA. The MAPK was enhanced 1 minute after hemolysate exposure and the effect reached maximum levels at 5 minutes. The immunoreactivity of MAPK decayed slowly over time, but the level of this kinase was still higher than the basal level, even at 2 hours after exposure to hemolysate. Preincubation of arteries with the MEK inhibitor PD-98059 abolished the effect of hemolysate on MAPK immunoreactivity.Conclusions. Hemolysate produced contraction of rabbit BA, possibly by activation of MAPK, and therefore MAPK inhibitors may be useful in the treatment of cerebral vasospasm.

Enhancement of C2-ceramide antitumor activity by small interfering RNA on X chromosome—linked inhibitor of apoptosis protein in resistant human glioma cells

2004 ◽  
Vol 101 (1) ◽  
pp. 119-127 ◽  
Author(s):  
Manabu Hatano ◽  
Masaaki Mizuno ◽  
Jun Yoshida
Keyword(s):  
Small Interfering Rna ◽  
Glioma Cells ◽  
Inhibitor Of Apoptosis ◽  
Human Glioma ◽  
Human Glioma Cells ◽  
Content Type ◽  
Inhibitor Of Apoptosis Protein ◽  
Apoptosis Protein ◽  
Interfering Rna ◽  
Fine Print

Object. Many human glioma cells are resistant to ceramide. In this study the authors investigated the mechanisms of that resistance and considered ways to overcome it. Methods. The authors first administered C2-ceramide (N-acetylsphingosine) to human glioma cells from rare cell lines susceptible to C2-ceramide (SKMG1 and U87MG) and other cell lines resistant to it (U251SP, T98G, SKAO2, and U251MG). Following this, the authors analyzed the statuses of transduction signals such as cell viability, morphological changes, caspases, mitochondrial membrane potential, apoptosis-inducing factor, oligonucleosomal DNA fragmentation, and the inhibitor of apoptosis protein (IAP) family. Conclusions. Ceramide resistance was found to arise from the inhibition of caspase-7 induced by IAPs, especially X chromosome—linked IAP (XIAP). Small interfering RNA (siRNA) on XIAP quenched that resistance in ceramide-resistant human glioma cells (U251SP, T98G, SKAO2, U251MG), indicating that a siRNA for XIAP may be a useful tool for overcoming the resistance to ceramide in human glioma cells.

scholarly journals Ganglioside GM1 Activates the Mitogen-Activated Protein Kinase Erk2 and p70 S6 Kinase in U-1242 MG Human Glioma Cells

2002 ◽  
Vol 69 (1) ◽  
pp. 116-125 ◽  
Author(s):  
James R. Van Brocklyn ◽  
J. R. Vandenheede ◽  
Richard Fertel ◽  
Allan J. Yates ◽  
Arfaan A. Rampersaud
Keyword(s):  
Protein Kinase ◽  
Glioma Cells ◽  
Mitogen Activated Protein Kinase ◽  
Human Glioma ◽  
Human Glioma Cells ◽  
Ganglioside Gm1 ◽  
S6 Kinase ◽  
P70 S6 Kinase ◽  
Mitogen Activated Protein

Wild-type p53—dependent etoposide-induced apoptosis mediated by caspase-3 activation in human glioma cells

2000 ◽  
Vol 93 (2) ◽  
pp. 289-297 ◽  
Author(s):  
Dali Yin ◽  
Norihiko Tamaki ◽  
Takashi Kokunai
Keyword(s):  
Glioma Cell ◽  
Glioma Cells ◽  
Human Glioma ◽  
Wild Type ◽  
Human Glioma Cells ◽  
Content Type ◽  
Low Concentrations ◽  
Wild Type P53 ◽  
Induced Apoptosis ◽  
Fine Print

Object. In an attempt to understand the roles of several apoptosis-related genes in human glioma cells, the authors investigated the relationship of wild-type p53, interleukin-1β—converting enzyme (ICE), caspase-3 (CPP32), bax, and bcl-2 to the apoptotic response of three glioma cell lines after treatment with etoposide.Methods. A human glioma cell line (U-87MG) that expresses wild-type p53, one that expresses mutant p53 (T-98G), and a T-98G derivative (T-98G/p53) that was transfected with a wild-type p53 expression vector (pCDM8-p53/neo) were used. Cell growth inhibition in response to etoposide was quantified using a modified methylthiazol tetrazolium colorimetric assay. Induction of apoptosis was evaluated using Hoechst 33258 staining and a DNA fragmentation assay. To study the expression of the apoptosis-related proteins and messenger RNAs in the three glioma cell lines, Western blotting and polymerase chain reaction were performed. A caspase assay and Western blot analysis were used to assess CPP32 and ICE protease activity. A CPP32 inhibition assay was used to determine whether a specific CPP32 inhibitor, DEVD-CHO, affects the apoptosis induced by etoposide in malignant glioma cells. Etoposide significantly inhibited the growth of U-87MG and T-98G/p53 cells in a dose-dependent manner compared with the growth of the T-98G cells. Treatment with low concentrations of etoposide resulted in the increased expression of wild-type p53; it also initiated CPP32 activity and induced apoptosis in the U-87MG cells. Apoptosis was not induced in T-98G cells at low concentrations of etoposide, although it was induced at high concentrations. Furthermore, low concentrations of etoposide also induced apoptosis in the T-98G/p53 cells by enhancing the expression of transfected wild-type p53, decreasing the expression of bcl-2, and activating CPP32 activity. However, etoposide did not alter the expression of bax and did not initiate ICE activity in these three glioma cell lines. Etoposide-induced apoptosis can be suppressed by the CPP32 inhibitor DEVD-CHO.Conclusions. These findings indicate that wild-type p53, CPP32, and bcl-2 may mediate apoptosis induced by etoposide. Forced expression of wild-type p53 increases etoposide cytotoxicity in human glioma cells by inducing apoptosis and may have important therapeutic implications.

Effects of MAPK inhibitors on cerebral vasospasm in a dog double hemorrhage model

2000 ◽  
Vol 93 (6) ◽  
pp. 1041-1047 ◽  
Author(s):  
Robert Tibbs ◽  
Alexander Zubkov ◽  
Kazuya Aoki ◽  
Toshinari Meguro ◽  
Ahmed Badr ◽  
...  
Keyword(s):  
Cerebral Vasospasm ◽  
Autologous Blood ◽  
Treated Group ◽  
Mitogen Activated Protein Kinase ◽  
Potential Candidate ◽  
Content Type ◽  
Mitogen Activated Protein ◽  
Mapk Inhibitors ◽  
Fine Print

Object. Mitogen-activated protein kinase (MAPK) may be involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage. This study was conducted to investigate the ability of the MAPK inhibitors PD98059 and U-0126 to reverse vasospasm in a double-hemorrhage model in dogs.Methods. Twenty-two adult mongrel dogs of either sex, each weighing 18 to 24 kg, were divided randomly into four groups: control SAH (four dogs), vehicle- (dimethyl sulfoxide, six dogs), PD-98059— (six dogs), and U-0126—treated groups (six dogs). The double-hemorrhage model was created by an autologous blood injection into the cisterna magna on Days 0 and 2. An intracisternal injection of MAPK inhibitors was administered once per day on Days 3 through 6. Cerebral angiography was performed on Days 0 and 7 before the animals were killed. Western blot analysis was used to study the effects of hemorrhage and drug treatment on the MAPK immunoprecipitation.Severe vasospasm developed in the dogs in the control and vehicle-treated groups (basilar artery [BA] diameter reduction 46.6 ± 5.5% and 49.3 ± 4.6%, respectively). In the PD-98059—treated group, most of the dogs developed mild vasospasm (18.9 ± 6.2%). In the U-0126—treated group, severe vasospasm was observed despite treatment (39.6 ± 6.4%). The PD-98059 but not the U-0126 abolished MAPK immunoprecipitation in the spastic BAs. However, treatment with either PD-98059 or U-0126 improved the clinical scores of the dogs.Conclusions. The present study is the first in which the effects of MAPK inhibitors on vasospasm have been investigated in vivo. The authors demonstrate that MAPK may play a role in vasospasm and that PD-98059 is a potential candidate for the treatment of cerebral vasospasm.

Cell cycle arrest and astrocytic differentiation resulting from PTEN expression in glioma cells

1999 ◽  
Vol 91 (5) ◽  
pp. 822-830 ◽  
Author(s):  
Jun-ichi Adachi ◽  
Katsumi Ohbayashi ◽  
Tomonari Suzuki ◽  
Tomio Sasaki
Keyword(s):  
Expression System ◽  
Biological Significance ◽  
Glioma Cells ◽  
Genetic Alterations ◽  
Pten Expression ◽  
Human Glioma ◽  
Wild Type ◽  
Content Type ◽  
Astrocytic Differentiation ◽  
Fine Print

Object. Genetic alterations of the PTEN gene (also known as MMAC1 or TEP1) have frequently been identified in high-grade gliomas, indicating that inactivation of PTEN plays a crucial role in human glioma progression. The aim of this study was to assess the biological significance of PTEN inactivation in the development of glioma.Methods. The authors introduced wild-type PTEN complementary DNA into four human glioma cell lines (T98G, U-251MG, U-87MG, and A172) containing endogenous aberrant PTEN alleles. The number of colonies transfected with the wild-type PTEN was reduced to 15 to 32% of those found after transfection of a control vector, suggesting growth suppression by the exogenous PTEN. To analyze phenotypic alterations produced by PTEN expression, T98G-derived clones with inducible PTEN expression were further established using a tetracycline-regulated inducible gene expression system. Induction of PTEN expression suppressed the in vitro growth of T98G cells with accumulation of G1 phase cells. Furthermore, when cells were cultured in the presence of the extracellular matrix (ECM), PTEN expression caused distinct morphological changes, with multiple and elongated cytoplasmic processes similar to those of normal astrocytes. The level of glial fibrillary acidic protein, an intermediate protein specifically expressed in differentiated astrocytes, was upregulated concomitantly.Conclusions. These findings strongly indicate that exogenous PTEN expression inhibits the proliferation of glioma cells by inducing G1 arrest and elicits astrocytic differentiation in the presence of the ECM. Inactivation of PTEN would play an important role in the enhancement of unregulated growth of undifferentiated glioma cells.

Administration of interleukin-12 and -18 enhancing the antitumor immunity of genetically modified dendritic cells that had been pulsed with Semliki Forest virus—mediated tumor complementary DNA

2002 ◽  
Vol 97 (5) ◽  
pp. 1184-1190 ◽  
Author(s):  
Ryuya Yamanaka ◽  
Naoki Yajima ◽  
Naoto Tsuchiya ◽  
Junpei Honma ◽  
Ryuichi Tanaka ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Antitumor Immunity ◽  
Semliki Forest Virus ◽  
Malignant Gliomas ◽  
Glioma Cells ◽  
Antitumor Effects ◽  
Content Type ◽  
Immunogene Therapy ◽  
Fine Print

Object. Immunogene therapy for malignant gliomas was further investigated in this study to improve its therapeutic efficacy. Methods. Dendritic cells (DCs) were isolated from bone marrow and pulsed with phosphate-buffered saline or Semliki Forest virus (SFV)—mediated 203 glioma complementary (c)DNA with or without systemic administration of interleukin (IL)-12 and IL-18 to treat mice bearing the 203 glioma. To study the immune mechanisms involved in tumor regression, the authors investigated tumor growth of an implanted 203 glioma model in T cell subset—depleted mice and in interferon (IFN) γ—neutralized mice. To examine the protective immunity produced by tumor inoculation, a repeated challenge of 203 glioma cells was given by injecting the cells into the left thighs of surviving mice and the growth of these cells was monitored. The authors demonstrated that the combined administration of SFV-cDNA, IL-12, and IL-18 produced significant antitumor effects against the growth of murine glioma cells in vivo and also can induce specific antitumor immunity. The synergic effects of the combination of SFV-cDNA, IL-12, and IL-18 in vivo were also observed to coincide with markedly augmented IFNγ production. The antitumor effects of this combined therapy are mediated by CD4+ and CD8+ T cells and by NK cells. These results indicate that the use of IL-18 and IL-12 in DC-based immunotherapy for malignant glioma is beneficial. Conclusions. Immunogene therapy combined with DC therapy, IL-12, and IL-18 may be an excellent candidate in the development of a new treatment protocol. The self-replicating SFV system may therefore provide a novel approach for the treatment of malignant gliomas.

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