共查询到20条相似文献,搜索用时 31 毫秒
1.
Chen H Mei L Zhou L Shen X Guo C Zheng Y Zhu H Zhu Y Huang L 《Journal of neuro-oncology》2011,104(1):155-167
Glioblastoma is the most frequent and malignant glioma in adults. To develop an effective gene therapy strategy for glioblastoma,
we investigated the anti-proliferative effects of phosphatase and tensin homolog (PTEN) restoration and siRNAs specifically
targeting PIK3CB and PIK3CA on PTEN-deficient glioblastoma cells in vitro and in subcutaneous xenografts. Restoration of PTEN
or knockdown of PIK3CB, but not PIK3CA, in glioblastoma cells markedly down-regulates the phosphorylation level of AKT, inhibits
cell proliferation and colony formation, arrests the cell cycle at the G0/G1 stage, and promotes caspase-dependent apoptosis.
Combined treatment with PTEN restoration and PIK3CB knockdown shows strong synergy. PTEN restoration or PIK3CB knockdown is
also able to efficiently inhibit the growth of human U251 glioblastoma xenografts in nude mice, while tumor growth is entirely
suppressed by a combination of the two treatments. In addition, we found that the mRNA levels of inhibitors of apoptosis proteins
(IAPs) are reduced in U251 cells by PTEN restoration, suggesting that combined antitumor effects may also be partly attributed
to the inhibition of the IAP pathway by PTEN restoration. Collectively, our results demonstrate that PI3 K isoforms play specific
roles in tumorigenesis, and that combined treatment of PTEN restoration and PIK3CB siRNA is a promising gene therapy strategy
for PTEN-deficient gliomas. 相似文献
2.
Lei Han An-ling Zhang Peng Xu Xiao Yue Yang Yang Guang-xiu Wang Zhi-fan Jia Pei-yu Pu Chun-sheng Kang 《Medical oncology (Northwood, London, England)》2010,27(3):843-852
The over-expression/amplification of the epidermal growth factor receptor (EGFR) gene and mutation/deletion of tumor suppressor
PTEN gene are main genetic changes identified in glioblastomas. These two genetic changes play a critical role in the formation
of many malignant tumors and have been shown to be the important therapeutic targets. In this study, we used an expression
plasmid that expresses small hairpin RNA-targeting sequences of human EGFR and wild-type PTEN cDNA to examine the growth inhibitive
effects in U251 glioma cells. It was found that down-regulation of EGFR expression and up-regulation of PTEN expression resulted
in the suppression of cell proliferation, arrest of cell cycle, reduction in cell invasion and promotion of cell apoptosis
in vitro. In addition, the growth of the subcutaneous U251 glioma in the nude mice treated with expression plasmid was significantly
inhibited. Our results demonstrated that the expression plasmid could exert proliferation and invasion inhibition effects
on U251 cells in vitro and in vivo. It suggested that combinatory gene therapy targeting EGFR and PTEN would be a new strategy
in gene therapy of glioblastoma. 相似文献
3.
Niola F Evangelisti C Campagnolo L Massalini S Buè MC Mangiola A Masotti A Maira G Farace MG Ciafrè SA 《Cancer biology & therapy》2006,5(2):174-179
Angiogenesis is required for the development and biologic progression of glioblastoma multiform (GBM), which is the most malignant infiltrative astrocytoma. Vascular endothelial growth factor (VEGF) plays a predominant role in the increased vascularity and endothelial cell proliferation in GBMs driven by the expression of pro-angiogenic cytokines. In this study, we employed a vector-encoded VEGF siRNA to impair VEGF secretion from U87 human glioblastoma cells. The direct intra-tumor injection of a siRNA-encoding plasmid complexed with linear polyethylenimine (PEI) efficiently reduced the vascularization of treated tumors in xenografts established in SCID mice by subcutaneous inoculation of U87 cells, but was not able to reduce tumor growth. We then sought to strengthen the in vivo action of our siRNA by coupling it to a well known direct antiangiogenic agent, mouse interleukin 4 (mIL4). We infected U87 cells with a retroviral vector coexpressing the VEGF siRNA and mIL4 and produced stable cell lines that we used for an in vivo experiment of subcutaneous injection in SCID mice. In this setting, the concomitant expression of mIL4 and siRNA totally abolished the growth of subcutaneous tumors. These results suggest that our retroviral vector might be employed as a potential tool in future antiangiogenic gene therapy trials for glioblastoma. 相似文献
4.
Suppression of EGFR expression by antisense or small interference RNA inhibits U251 glioma cell growth in vitro and in vivo 总被引:5,自引:0,他引:5
Kang CS Zhang ZY Jia ZF Wang GX Qiu MZ Zhou HX Yu SZ Chang J Jiang H Pu PY 《Cancer gene therapy》2006,13(5):530-538
Epidermal growth factor receptor (EGFR) had been reported as one of the major responsible genes for malignant progression and phenotype reversion of gliomas, and has been used as one of the most important therapeutic targets. In the present study, small interference RNA (siRNA) and antisense EGFR expression constructs, which target sequences of human EGFR catalytic domain (2400-2420) and the 3'-coding region, respectively, were used to examine the growth inhibition effects on U251 glioma cells. Cell growth was significantly inhibited and G2/M arrest was observed in antisense- and siRNA-treated groups. Matrigel matrix demonstrated spotted cell clustering pattern in antisense- and siRNA-transfected U251 cells, indicating poor cell growth activities. In addition, the tumor volumes in U251 subcutaneous mice model treated with antisense and siRNA were significantly smaller than those treated with control siRNA and phosphate-buffered saline. Also, glial fibrillary acidic protein expression was upregulated in antisense- and siRNA-treated groups than the control groups. Our results demonstrated that antisense- or siRNA-targeting intracellular region of EGFR can inhibit EGFR expression, exerted growth inhibition effect on U251 glioma cells in vitro and in vivo. Consequently, siRNA expression plasmid-mediated gene therapy would be a new strategy in treatment of gliomas. 相似文献
5.
Tanaka K Sasayama T Mizukawa K Kawamura A Kondoh T Hosoda K Fujiwara T Kohmura E 《Journal of neuro-oncology》2007,84(3):233-244
Loss of the PTEN tumor suppressor gene and amplification of the epidermal growth factor receptor (EGFR), which is common in
malignant gliomas, result in activation of the mammalian target of rapamycin (mTOR). Rapamycin is a highly specific inhibitor
of mTOR and induces a cytostatic effect in various glioma cell lines. DNA-damaging agents such as nitrosourea are widely used
in malignant glioma treatment; therefore, we investigated the effect of rapamycin on cell growth and death in combination
with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU, nimustine hydrochloride) in human glioma
cells. In U251 malignant glioma (U251MG) cells, we confirmed that rapamycin enhanced ACNU-induced apoptosis. We found that
rapamysin inhibited ACNU-induced p21 induction, and knocking down of p21 protein by siRNA enhanced ACNU-induced apoptosis
in U251MG cells. Furthermore, adenovirus-mediated over-expression of p21 protein rescued U251MG cells from apoptosis induced
by ACNU and rapamycin. Finally, treatment of intracerebral U251MG xenografts with a combination of rapamycin and ACNU in vivo
resulted in statistically prolonged median survival (P < 0.05). These results suggest that rapamycin in combination with DNA-damaging agents may be efficacious in the treatment
of malignant gliomas. 相似文献
6.
Hueng DY Lin GJ Huang SH Liu LW Ju DT Chen YW Sytwu HK Chang C Huang SM Yeh YS Lee HM Ma HI 《Journal of neuro-oncology》2011,104(1):21-31
Angiogenesis is the hallmark of malignant gliomas positively correlated with the vascular endothelial growth factor (VEGF) expression. We previously reported that expression levels of Nodal, a member of transforming growth factor-β super family, correlate with the malignant invasive behavior of human glioma cells. In this study, we show that knockdown of Nodal suppresses glioma angiogenesis by inhibition of VEGF. In human primary glioma specimens, expression of Nodal positively correlates with WHO glioma tumor grades and expression of VEGF in the corresponding glioma specimens. In human U87MG glioma cells, knockdown of endogenous Nodal by RNA interference (RNAi) significantly decreases colony formation and secretion of VEGF. In vivo, cellular depletion of Nodal in U87MG inhibited brain glioma growth and prolonged the survival of mice with U87MG/shNodal glioma compared with controls. Inhibition of Nodal suppressed tumor vessel growth in U87MG gliomas. Using Nodal inhibitor (SB431542), silencing Nodal, or overexpressing Nodal in the U87MG, GBM8401, and GBM glioma cells, our further experiments revealed that Nodal-induced VEGF expression might, at least in part, mediate through the ERK1/2-HIF-1α-mediated signaling pathway. Taken together, our data revealed that alteration of Nodal expression in glioma cells resulted in changes to VEGF secretion, and subsequent colony formation, in vivo tumor growth, and angiogenesis, all of which are consistent with the regulation of VEGF through the ERK1/2-HIF-1α-mediated signaling, suggesting that Nodal may serve as a potential therapeutic target for the treatment of human gliomas. 相似文献
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Feng Xuequan Zhang Biao Wang Jinhuan Xu Xinnv Lin Na Liu Hongsheng 《Medical oncology (Northwood, London, England)》2011,28(1):24-30
Basic fibroblast growth factor (bFGF) is an important growth factor for glioma cell proliferation and invasion. BFGF is overexpressed
in malignant gliomas and its level is associated with malignant grades and clinical outcome of patients with gliomas. Small
interfering RNAs (siRNA) are synthetic forms of microRNA made of short double stranded RNA, and they effectively catalyze
the degradation of their target mRNA. The use of siRNA has become a key method in the suppression of gene expression and the
development of therapeutic agents. In this study, we used an adenovirus(Ad)-mediated transfer of siRNA against bFGF mRNA (Ad-bFGF-siRNA)
to study the effect of down-regulating bFGF expression on the sensitivity of glioma cells to chemotherapeutics. An optimal
siRNA sequence specific for bFGF mRNA was cloned into an adenoviral vector and transfected into three glioma cell lines: U251,
A172, and LN229. Methyl thiazolyl tetrazolium (MTT) assays were used to examine changes in cell proliferation, and changes
in bFGF mRNA and protein levels in U251 cells were detected using quantitative RT-PCR and Western blot, respectively. Apoptosis
of U251 cells was detected using Hoechst staining and flow cytometry, with expression of apoptosis-related proteins evaluated
by Western blot. Following the transfection of a bFGF-specific siRNA, mRNA and protein levels of bFGF decreased significantly.
Lower rates of proliferation and increased levels of apoptosis also were associated with the Ad-bFGF-siRNA-transfected group
compared to control group. Decreased expression of Bcl-2, Bcl-xL, Jak-1, and STAT-3 and increased expression of Bax also were
detected in the Ad-bFGF-siRNA-transfected group. For cells treated with both Ad-bFGF-siRNA and chemotherapeutics, a significant
reduction in cell survival was observed compared to treatment with Ad-bFGF-siRNA or chemotherapeutics alone. Overall, we found
that targeting bFGF mRNA with a siRNA resulted in lower rates of proliferation, increased apoptosis, and enhanced sensitivity
of glioma cells to chemotherapy drugs. This suggests that specific targeting of bFGF mRNA may provide a novel approach for
the treatment of glioblastoma multiforme (GBM). 相似文献
9.
Mechanisms operative in the antitumor activity of temozolomide in glioblastoma multiforme 总被引:3,自引:0,他引:3
Fisher T Galanti G Lavie G Jacob-Hirsch J Kventsel I Zeligson S Winkler R Simon AJ Amariglio N Rechavi G Toren A 《Cancer journal (Sudbury, Mass.)》2007,13(5):335-344
PURPOSE: Glioblastoma multiforme (GBM) is the most frequent and incurable brain tumor in adults. Although temozolomide (TMZ) does not cure GBM, it has demonstrated anti-GBM activity and has improved survival (8-14 months) and quality of life. We studied the mechanisms by which TMZ affects 2 human GBM cell lines; U251-MG and U87-MG, aiming to unravel the drug-activated cascades to enable the development of combination therapies that will improve the efficacy of TMZ. MATERIALS AND METHODS: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay was used to assess cell viability. Modulation of gene expression by TMZ therapy was assayed by gene profiling and verified by quantitative real-time polymerase chain reaction. Protein levels influenced by the treatment were studied by Western blots and immunocytochemistry. RESULTS: Increasing concentrations of TMZ decreased cell viability in a concentration-dependent manner. The expression of 1,886 genes was altered >2-fold after TMZ treatment. We focused on the 81 genes similarly altered by TMZ treatment in both cell lines to neutralize tissue-specific characteristics. Fourteen target genes of hypoxia-inducible factor (HIF-1), were found to be up-regulated after TMZ treatment including vascular endothelial growth factor (VEGF). HIF-1alpha expression was constant at the mRNA level; however, its post-treatment protein levels increased compared with those of untreated control cells. DISCUSSION: The genetic analyses suggest that treatment with TMZ activates stress mechanisms in GBM cells that include the angiogenesis-inducing proteins HIF-1alpha and VEGF. We propose that treatment with TMZ be supplemented with either an antibody to VEGF or down-regulators of HIF-1alpha to improve clinical results of TMZ in the treatment of GBM. 相似文献
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Radiation-Enhanced Vascular Endothelial Growth Factor (VEGF) Secretion in Glioblastoma Multiforme Cell Lines – A Clue to Radioresistance? 总被引:5,自引:0,他引:5
Hovinga KE Stalpers LJ van Bree C Donker M Verhoeff JJ Rodermond HM Bosch DA van Furth WR 《Journal of neuro-oncology》2005,74(2):99-103
Summary Objective: Postoperative radiotherapy is standard treatment for patients with a glioblastoma multiforme (GBM). However, a GBM is radioresistant
and almost always recurs, even after a high dose of radiation. A GBM is characterized by its extensive neo-angiogenesis, which
can be attributed to the high levels of vascular endothelial growth factor (VEGF). The scope of this study is to investigate
the VEGF secretion by GBM cells with different radiosensitivity after irradiation. Methods:Three human GBM cell lines (U251, U251-NG2 and U87) were irradiated with single doses of 0, 5, 10 and 20 Gy of γ-rays from a 137Cs source. VEGF levels in medium were measured by ELISA at 24, 48 and 72 h after radiation. Cell survival was measured by
the XTT assay 7 days after irradiation. Results:Following single dose radiation, the VEGF levels showed a dose dependent increase in U251, U251-NG2 and U87 glioma cells.
Both base-line and radiation-enhanced VEGF levels were about 10-fold higher in U87 compared to U251 and U251-NG2 cells. In
addition, in the XTT assay, the U87 was more radioresistant than both U251 and U251-NG2 cell lines (dose modifying factor
(DMF) = 1.6 and 1.7 resp). Conclusion:Irradiation enhanced VEGF secretion in all three tested glioma cell lines (up to eight times basal levels). It is tempting
to associate the radiation-enhanced VEGF secretion with an increased angiogenic potential of the tumor, which may be a factor
in radioresistance. 相似文献
14.
Amir Alahverdi Ehsan ArefianMasoud SoleimaniJafar AiAaliakbar Yousefi-AhmadipourAbouzar BabaeiMd Shahidul IslamSomayeh Ebrahimi-Barough 《Asian Pacific journal of cancer prevention》2020,21(12):3469-3475
GBM (Glioblastoma multiforme) is the most prevalent and lethal primary brain tumor. Gene therapy is one of the promising approaches and involves the delivery of genetic therapeutic molecules for specific antitumour response/activity. miRNAs can regulate the cell biology functions including replication, cell growth, and apoptosis by regulating gene expression. In this study, we found that down-regulation of miR-4731 expression occurred in GBM cells. We further determined that miR-4731 behaved as a tumor suppressor by inhibiting GBM cell proliferation. We further investigated the molecular mechanisms of miR-4731 and EGFR, ERK-1,2 and AKT-1,2 in GBM cell lines U87 and U251. The in vitro ectopic expression of miR-4731 affected cell proliferation, migration, and invasion of U87 and U251 cells. Luciferase reporter assays validated that miR-4731 targeted the 3′-untranslated region (3′-UTR) of EGFR. In conclusions, we identified that miR-4731 plays a tumor suppressor role in GBM cell proliferation and migration by targeting EGFR expression, and miR-4731 may act as a novel biomarker for early diagnosis or therapeutic target of GBM. 相似文献
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背景与目的:克隆人野生型和突变型PTEN的cDNA并构建其表达载体,探讨该表达质粒在人星形胶质瘤细胞U251中的表达情况.材料与方法:分别从新鲜胎盘组织和结肠癌组织中提取总RNA,采用RT-PCR的方法扩增人野生型和突变型PTEN基因全长cDNA,分别克隆入pMD 18-T载体上,经PCR、酶切鉴定均为阳性的克隆,进行核苷酸序列分析.再分别将两段基因定向克隆入pcDNA3.1( )载体中构建表达载体,转染入U251细胞.结果:成功克隆了人野生型及突变型PTEN cDNA并成功构建其表达载体,发现突变型PTEN蛋白对细胞生长无明显抑制作用,而野生型PTEN蛋白对细胞生长有明显抑制作用.结论:PTEN可能能抑制肿瘤细胞生长,为后进一步开展PTEN对肿瘤相关功能的研究奠定基础. 相似文献
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Inhibition of Aurora kinase B has been evaluated as a therapy to block solid tumor growth in breast cancer, hepatocellular carcinoma, lung adenocarcinoma, and colorectal cancer models. Aurora kinase inhibitors are in early clinical trials for the treatment of leukemia. We hypothesized that Aurora B inhibition would reduce malignant glioma cell viability and result in impaired tumor growth in vivo. Aurora B expression is greater in cultured malignant glioma U251 cells compared to proliferating normal human astrocytes, and expression is maintained in U251 flank xenografts. Aurora B inhibition with AZD1152-HQPA blocked cell division in four different p53-mutant glioma cell lines (U251, T98G, U373, and U118). AZD1152-HQPA also inhibited Aurora C activation loop threonine autophosphorylation at the effective antiproliferative concentrations in vitro. Reduction in cell viability of U251 (p53(R273H)) cells was secondary to cytokinesis blockade and apoptosis induction following endoreplication. AZD1152-HQPA inhibited the growth of U251 tumor xenografts and resulted in an increase in tumor cell apoptosis both in vitro and in vivo. Subcutaneous administration of AZD1152-HQPA (25 mg/kg/day × 4 days; 2 cycles spaced 7 days apart) resulted in a prolongation in median survival after intracranial inoculation of U251 cells in mice (P = 0.025). This is the first demonstration that an Aurora kinase inhibitor can inhibit malignant glioma growth in vivo at drug doses that are clinically relevant. 相似文献
19.
Analysis using the public microarray database Gene Expression Omnibus indicates significantly higher mRNA expression of VEGF and VEGFRs in colorectal cancer and high grade astrocytoma but not in hepatocellular carcinoma compared to normal tissue. Human malignant astrocytoma cell lines (U251-MG and U373-MG) and HT-1080 fibrosarcoma cells expressed relatively higher levels of VEGF and VEGFRs compared to hepatocellular and colorectal cancer cell lines. Administration of exogenous VEGF-A induced cell growth in a dose-dependent fashion in astrocytoma and fibrosarcoma cells but not in colorectal and hepatocellular cancer cells. The blockade of VEGF inhibited cell survival only in U251-MG, U373-MG and HT-1080 cells. These results collectively suggest the role of autocrine VEGF signaling in various cancer cells and provide a basis for the variable clinical responses to antiangiogenic therapy observed in different types of malignancies. 相似文献
20.
Wang MY Lu KV Zhu S Dia EQ Vivanco I Shackleford GM Cavenee WK Mellinghoff IK Cloughesy TF Sawyers CL Mischel PS 《Cancer research》2006,66(16):7864-7869
The epidermal growth factor receptor (EGFR) is commonly amplified, overexpressed, and mutated in glioblastoma, making it a compelling molecular target for therapy. We have recently shown that coexpression of EGFRvIII and PTEN protein by glioblastoma cells is strongly associated with clinical response to EGFR kinase inhibitor therapy. PTEN loss, by dissociating inhibition of the EGFR from downstream phosphatidylinositol 3-kinase (PI3K) pathway inhibition, seems to act as a resistance factor. Because 40% to 50% of glioblastomas are PTEN deficient, a critical challenge is to identify strategies that promote responsiveness to EGFR kinase inhibitors in patients whose tumors lack PTEN. Here, we show that the mammalian target of rapamycin (mTOR) inhibitor rapamycin enhances the sensitivity of PTEN-deficient tumor cells to the EGFR kinase inhibitor erlotinib. In two isogenic model systems (U87MG glioblastoma cells expressing EGFR, EGFRvIII, and PTEN in relevant combinations, and SF295 glioblastoma cells in which PTEN protein expression has been stably restored), we show that combined EGFR/mTOR kinase inhibition inhibits tumor cell growth and has an additive effect on inhibiting downstream PI3K pathway signaling. We also show that combination therapy provides added benefit in promoting cell death in PTEN-deficient tumor cells. These studies provide strong rationale for combined mTOR/EGFR kinase inhibitor therapy in glioblastoma patients, particularly those with PTEN-deficient tumors. 相似文献