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1.
Leucine-rich repeat C4 (LRRC4) has been shown to inhibit glioma cell proliferation, however, little is known about the mechanism(s) underlying the action of LRRC4. Here, we show that two glioblstoma U251 cell clones stably expressing LRRC4 were established. LRRC4 expression significantly inhibited the expression of some cytokines and their receptors determined by microarray and Western blot assays, and dramatically reduced cytokine-induced AP-1, NF-kB, and CyclinD1 activation in glioma cells. Furthermore, LRRC4 expression in glioma cells significantly downregulated spontaneous and cytokine-induced expression of K-RAS and phosphorylation of c-Raf, ERK, AKT, NF-kBp65, p70S6K, and PKC, suggesting that LRRC4 inhibited receptor tyrosine kinase (RTK) signaling pathways. Moreover, treatment with bFGF, IGF1, or IGF2 stimulated LRRC4(-/-), but not the LRRC4(+), glioma cell proliferation, indicating that LRRC4 mitigated cytokine-stimulated proliferation in glioma cells. In addition, treatment of LRRC4(-/-) glioma cells with EGF, IGF2, or PDGF promoted long distance mobilization, but induced little migration in LRRC4(+) glioma cells, suggesting that LRRC4 retarded cytokine-promoted glioma cell migration in vitro. Finally, human vessel endothelial cells (ECV304) treated with VEGF grew, aligned and formed hollow tube-like structures in vitro. In contrast, LRRC4(+) ECV304 treated with VEGF failed to form vessel-tube structures. Collectively, LRRC4 expression inhibited the expression of some growth factors, cytokines and their receptors, and the capacity of glioma cells responding to cytokine stimulation, leading to inhibition of glioma cell proliferation. Conceivably, induction of LRRC4 expression may provide new intervention for human glioma in the clinic.  相似文献   

2.
Long non‐coding RNAs have recently become a key regulatory factor for cancers, whereas FER1L4, a newly discovered long non‐coding RNA, has been mostly studied in gastric carcinoma and colon cancer cases. The functions and molecular mechanism of FER1L4 have been rarely reported in glioma malignant phenotypes. In this study, it was found that the expression of LncRNA FER1L4 is upregulated in high‐grade gliomas than in low‐grade cases and that a high expression of LncRNA FER1L4 predicts poor prognosis of gliomas. Meanwhile, in vitro study suggests that expression of FER1L4 with SiRNA knockdown obviously suppresses cell cycle and proliferation. It is further demonstrated by experiments that the FER1L4 knockdown suppresses growth of in vivo glioma. Besides, it is found in our study that LncRNA FER1L4 expression is positively correlated with E2F1 mRNA expression. After knockdown of FER1L4 expression, E2F1 expression is significantly down‐regulated, whereas the expression of miR‐372 is significantly up‐regulated; the up‐regulation of miR‐372 leads to significant down‐regulation of FER1L4 and E2F1 expression. In addition, it is also found that FER1L4 can be used as competitive endogenous RNA to interact or bind with miR‐371 and thereby up‐regulate E2F1, thus promoting the cycle and proliferation of glioma cells. It may be one of the molecular mechanisms in which FER1L4 plays its oncogene‐like role in gliomas.  相似文献   

3.
BACKGROUND: Many tumor cells are resistant to Apo2L/TRAIL-induced apoptosis in the absence of inhibitors of protein synthesis. Apo2L/TRAIL, in addition to induction of apoptosis, may therefore also activate survival pathways. METHODS: Here we investigated whether such survival pathways mediate resistance to Apo2L.0-induced apoptosis in human glioma cells. RESULTS: Apo2L.0 induced the phosphorylation of ERK1/2, but not of Akt. This effect was unaffected by caspase inhibition. Inhibitors of protein synthesis, PI3 kinase, ERK kinase, NF-kappaB or casein kinase 2 sensitized for Apo2L.0-induced apoptosis to a different extent in a panel of human malignant glioma cell lines. However, none of the sensitizers overcame resistance mediated by ectopic expression of the viral caspase 8 inhibitor, crm-A. Primary glioma cultures were almost completely resistant to Apo2L.0-induced cell death even in the presence of the inhibitors. Caspase-8 was expressed in these cells whereas only weak expression of DR5 was detected. Transient expression of DR5 conferred sensitivity to Apo2L.0. CONCLUSION: These data challenge the view that specific cell lines harbour specific mechanisms of resistance to Apo2L/TRAIL. Weak expression of DR5 in primary glioma might limit the therapeutic application of Apo2L/TRAIL in human glioblastoma patients.  相似文献   

4.
We recently found that formylpeptide receptor (FPR), a G-protein-coupled receptor that mediates chemotaxis of phagocytic leukocytes induced by bacterial peptide N-formyl-methionyl-leucyl-phenylalanine, is expressed by malignant human glioma cells and promotes tumor growth and angiogenesis. In this study, we examined the effect of Nordy, a novel chiral lipoxygenase inhibitor which was synthesized based on the structure of a natural nordihydroguaiaretic acid, on the expression of FPR by human glioblastoma cells. We found that FPR was expressed at the protein level by highly malignant human glioma cell lines U87 and BT325, and a rat glioma cell line C6. The expression level of FPR was correlated with the degree of the malignancy of tumor cells. The poorly differentiated glioma cell line U87 expressed the highest level of FPR. In U87 glioma cells, the expression of FPR was attenuated at the protein level by Nordy treatment for 48 (P<0.05). Nordy did not affect FPR mRNA expression in U87 cells. In addition, Nordy treatment seemed to promote glioma cell differentiation, as evidenced by their reduced expression of vimentin and increased expression of GFAP. Our results suggest that Nordy was capable of reducing the level of malignancy of glioma cells.  相似文献   

5.
LRRC4 is a tumor suppressor of glioma, and it is epigenetically inactivated commonly in glioma. Our previous study has shown that induction of LRRC4 expression inhibits the proliferation of glioma cells. However, little is known about the mechanisms underlying the action of LRRC4 in glioma cells. We employed two-dimensional fluorescence differential gel electrophoresis (2-D DIGE) and MALDI -TOF/TOF-MS/MS to identify 11 differentially expressed proteins, including the significantly down-regulated STMN1 expression in the LRRC4-expressing U251 glioma cells. The levels of STMN1 expression appeared to be positively associated with the pathogenic degrees of human glioma. Furthermore, induction of LRRC4 over-expression inhibited the STMN1 expression and U251 cell proliferation in vitro, and the glioma growth in vivo. In addition, induction of LRRC4 or knockdown of STMN1 expression induced cell cycle arrest in U251 cells, which was associated with modulating the p21, cyclin D1, and cyclin B expression, and the ERK phosphorylation, and inhibiting the CDK5 and cdc2 kinase activities, but increasing the microtubulin polymerization in U251 cells. LRRC4, at least partially by down-regulating the STMN1expression, acts as a major glioma suppressor, induces cell cycle arrest and modulates the dynamic process of microtubulin, leading to the inhibition of glioma cell proliferation and growth. Potentially, modulation of LRRC4 or STMN1 expression may be useful for design of new therapies for the intervention of glioma.  相似文献   

6.
The effect of vitamin E on proliferation, integrin expression, adhesion, and migration in human glioma cells has been studied. gamma-tocopherol at 50 microM concentration exerted more inhibitory effect than alpha-tocopherol at the same concentration on glioma cell proliferation. Integrin alpha5 and beta1 protein levels were increased upon both alpha- and gamma-tocopherol treatments. In parallel, an increase in the alpha5beta1 heterodimer cell surface expression was observed. The tocopherols inhibited glioma cell-binding to fibronectin where gamma-tocopherol treatment induced glioma cell migration. Taken together, the data reported here are consistent with the notion that the inhibition of glioma cell proliferation induced by tocopherols may be mediated, at least in part, by an increase in integrin alpha5 and beta1 expression. Cell adhesion is also negatively affected by tocopherols, despite a small increase in the surface appearance of the alpha5beta1 heterodimer. Cell migration is stimulated by gamma-tocopherol. It is concluded that alpha5 and beta1 integrin expression and surface appearance are not sufficient to explain all the observations and that other integrins or in general other factors may be associated with these events.  相似文献   

7.
脑胶质瘤是原发性颅内恶性肿瘤。患者的5年存活率不足1%。目前,除手术切除外,尚无有效的治疗手段。近年来发现,脑胶质瘤发病可能与多种钾离子通道的异常表达有关。自噬是膜包裹部分胞质和细胞内需降解的蛋白质、细胞器,并与溶酶体一起降解其所包裹内容物的生理过程。诱导胶质瘤细胞的自噬,促进其凋亡是肿瘤治疗的一种新策略。本室前期研究发现,电压依赖型钾通道1.5(Kv1.5)参与胞膜小窖标志蛋白质(caveolae,Cav-1)介导的多种肿瘤细胞的增殖和凋亡,但是否参与胶质瘤细胞的自噬并不清楚。本文首先利用不同浓度的K+通道阻断剂四乙胺(tetra-ethylammonium,TEA)、Kv通道阻断剂四氨基吡啶(4-amino-pyridine,4-AP)和Kv1.5通道特异性阻断剂DPO-1(diphenyl phosphine oxide-1)分别在不同时间,作用于人脑胶质瘤细胞U251,观察其对细胞存活的影响。发现DPO-1对U251细胞具有双向作用:低浓度促进存活,高浓度抑制存活。其中,1 mmol/L DPO-1处理6 h,可促进自噬相关蛋白质LC3的表达,而抑制mTOR信号蛋白质的磷酸化水平,表明Kv1.5通道可能参与胶质瘤细胞的自噬。然后,利用基因转染技术分别敲低和过表达Kv1.5通道的蛋白质水平,发现敲低Kv1.5通道蛋白,促进胶质瘤细胞的自噬,激活ERK信号通路,而过表达Kv1.5通道蛋白,则抑制胶质瘤细胞的自噬。进一步利用流式细胞技术观察细胞凋亡,发现改变Kv1.5通道蛋白的表达水平,可诱发细胞早期凋亡。提示Kv1.5通道参与人脑胶质瘤细胞的自噬过程。这为临床利用特异性Kv通道阻断剂靶向治疗胶质瘤提供了新的理论和实验依据。  相似文献   

8.
Gliomas, the most malignant form of brain tumors, contain a small subpopulation of glioma stem cells (GSCs) that are implicated in therapeutic resistance and tumor recurrence. Topoisomerase I inhibitors, shikonin and topotecan, play a crucial role in anti-cancer therapies. After isolated and identified the GSCs from glioma cells successfully, U251, U87, GSCs-U251 and GSCs-U87 cells were administrated with various concentrations of shikonin or topotecan at different time points to seek for the optimal administration concentration and time point. The cell viability, cell cycle and apoptosis were detected using cell counting kit-8 and flow cytometer to observe the inhibitory effects on glioma cells and GSCs. We demonstrated that shikonin and topotecan obviously inhibited proliferation of not only human glioma cells but also GSCs in a dose- and time-dependent manner. According to the IC50 values at 24 h, 2 μmol/L of shikonin and 3 μmol/L of topotecan were selected as the optimal administration concentration. In addition, shikonin and topotecan induced cell cycle arrest in G0/G1 and S phases and promoted apoptosis. The down-regulation of Bcl-2 expression with the activation of caspase 9/3-dependent pathway was involved in the apoptosis process. Therefore, the above results showed that topoisomerase I inhibitors, shikonin and topotecan, inhibited growth and induced apoptosis of GSCs as well as glioma cells, which suggested that they might be the potential anticancer agents targeting gliomas to provide a novel therapeutic strategy.  相似文献   

9.
为了研究EphA2对神经胶质瘤细胞系U251在增殖、凋亡、迁移和侵袭方面所起的作用,用RT-PCR方法检测正常脑组织标本与两种恶性胶质瘤细胞系中EphA2 mRNA表达水平,然后用化学合成的针对EphA2基因的小干扰RNA(siRNA)下调该基因的表达,以检测其在U251中的生物学功能.证实了EphA2基因在正常脑组织标本中的表达水平远低于两种恶性胶质瘤细胞系.把体外化学合成针对EphA2基因的小干扰RNA(siRNA- EphA2)转染入U251细胞后,Western blot, 实时定量 RT-PCR检测到U251细胞中EphA2蛋白及mRNA表达水平都明显降低,并且细胞增殖受到显著抑制,同时出现了明显的细胞凋亡.伤口愈合实验(检测细胞迁移能力),Transwell小室实验(检测细胞侵袭能力)均表明,下调EphA2的表达后,细胞的迁移和侵袭能力较阴性对照组显著减弱.上述结果表明,在神经胶质瘤U251细胞中,EphA2与其恶性增殖及高度侵染性相关,可作为分子治疗的有效靶点.  相似文献   

10.
Gliomas are the most common and aggressive primary tumors in the central nervous system. Recently, Max interactor-1 (MXI1), an antagonist of c-Myc that is involved in brain tumor progression, has been reported to be deregulated in a variety of tumors including glioma. However, the mechanism of MXI1 deregulation in gliomas remains unclear. In this study, we show that the relative expression level of MXI1 is markedly down-regulated in glioma cell lines. Using integrated bioinformatic analysis and experimental confirmation, we identified several miRNAs by screening a panel of predicted miRNAs that may regulate the MXI1 3′UTR. The strongest inhibitory miRNA, miR-155, can attenuate the activity of a luciferase reporter gene that is fused with the MXI1 3′UTR and decrease the expression levels of MXI1 mRNA and protein in U87 glioma cells. The potential role of miR-155 in promoting glioma cell proliferation by targeting MXI1 was confirmed in various glioma cell lines by rescue experiments using MTT assays, EdU incorporation assay, and cell counting experiments. In addition, we determined that the level of MXI1 mRNA was inversely correlated with the expression of miR-155 in 18 sets of glioblastoma multiforme specimens. These findings reveal for the first time that the targeting of MXI1 by miR-155 may result in a reduction in MXI1 expression and promote glioma cell proliferation; this result suggests a novel function of miR-155 in targeting MXI1 in glioma-genesis.  相似文献   

11.
12.
Valproic acid (VPA), an histone deacetylase inhibitor, is emerging as a promising therapeutic agent for the treatments of gliomas by virtue of its ability to reactivate the expression of epigenetically silenced genes. VPA induces the unfolded protein response (UPR), an adaptive pathway displaying a dichotomic yin yang characteristic; it initially contributes in safeguarding the malignant cell survival, whereas long-lasting activation favors a proapoptotic response. By triggering UPR, VPA might tip the balance between cellular adaptation and programmed cell death via the deregulation of protein homeostasis and induction of proteotoxicity. Here we aimed to investigate the impact of proteostasis on glioma stem cells (GSC) using VPA treatment combined with subversion of SEL1L, a crucial protein involved in homeostatic pathways, cancer aggressiveness, and stem cell state maintenance. We investigated the global expression of GSC lines untreated and treated with VPA, SEL1L interference, and GSC line response to VPA treatment by analyzing cell viability via MTT assay, neurosphere formation, and endoplasmic reticulum stress/UPR-responsive proteins. Moreover, SEL1L immunohistochemistry was performed on primary glial tumors. The results show that (i) VPA affects GSC lines viability and anchorage-dependent growth by inducing differentiative programs and cell cycle progression, (ii) SEL1L down-modulation synergy enhances VPA cytotoxic effects by influencing GSCs proliferation and self-renewal properties, and (iii) SEL1L expression is indicative of glioma proliferation rate, malignancy, and endoplasmic reticulum stress statuses. Targeting the proteostasis network in association to VPA treatment may provide an alternative approach to deplete GSC and improve glioma treatments.  相似文献   

13.
DIX domain containing 1 (DIXDC1), the human homolog of coiled-coil-DIX1 (Ccd1), is a positive regulator of Wnt signaling pathway. Recently, it was found to act as a candidate oncogene in colon cancer, non-small-cell lung cancer, and gastric cancer. In this study, we aimed to investigate the clinical significance of DIXDC1 expression in human glioma and its biological function in glioma cells. Western blot and immunohistochemistry analysis showed that DIXDC1 was overexpressed in glioma tissues and glioma cell lines. The expression level of DIXDC1 was evidently linked to glioma pathological grade and Ki-67 expression. Kaplan–Meier curve showed that high expression of DIXDC1 may lead to poor outcome of glioma patients. Serum starvation and refeeding assay indicated that the expression of DIXDC1 was associated with cell cycle. To determine whether DIXDC1 could regulate the proliferation and migration of glioma cells, we transfected glioma cells with interfering RNA-targeting DIXDC1; investigated cell proliferation with Cell Counting Kit (CCK)-8, flow cytometry assays, and colony formation analyses; and investigated cell migration with wound healing assays and transwell assays. According to our data, knockdown of DIXDC1 significantly inhibited proliferation and migration of glioma cells. These data implied that DIXDC1 might participate in the development of glioma, suggesting that DIXDC1 can become a potential therapeutic strategy for glioma.  相似文献   

14.

Background  

Malignant glioma cells are particularly motile and can travel diffusely through the brain parenchyma, apparently without following anatomical structures to guide their migration. The neural adhesion/recognition protein L1 (L1CAM; CD171) has been implicated in contributing to stimulation of motility and metastasis of several non-neural cancer types. We explored the expression and function of L1 protein as a stimulator of glioma cell motility using human high-grade glioma surgical specimens and established rat and human glioma cell lines.  相似文献   

15.
ABCE1是ATP结合盒蛋白亚家族成员之一,在病毒感染,细胞增殖,抗凋亡,翻译起始和核糖体生物发生等过程中有重要的作用。为了探讨ABCE1对神经胶质瘤细胞U251增殖、迁移和凋亡的作用,本研究通过实时荧光定量PCR和免疫印迹实验检测ABCE1在神经胶质瘤细胞和正常胶质细胞中的mRNA和蛋白质表达水平,结果发现ABCE1在神经胶质瘤细胞U251中的表达高于在正常胶质细胞中的表达。利用siRNA靶向沉默ABCE1后,神经胶质瘤细胞U251中ABCE1 mRNA和蛋白的表达水平均显著减少,细胞的凋亡率显著提高,细胞增殖和迁移明显受到抑制,而且细胞对化疗药物替莫唑胺的敏感性增强。此外,沉默ABCE1后,Bcl-2的mRNA和蛋白质表达水平显著下调,而Bax的mRNA和蛋白质表达水平显著上调。以上研究结果表明,ABCE1与神经胶质瘤细胞的增殖和迁移密切相关,通过siRNA靶向沉默ABCE1基因可显著降低U251细胞的增殖和迁移能力。  相似文献   

16.
Chunghyuldan (CHD), a combinatorial drug that has antihyperlipidemic and anti-inflammatory activities, has been shown to improve arterial stiffness and inhibit stroke recurrence in clinical study. To understand the molecular basis of CHD's clinical effects, we explored its effect on cell proliferation and expression of nitric oxide synthase (NOS) and vascular cell adhesion molecule (VCAM-1) in human umbilical vein endothelial cells (HUVECs). Cell number counting and [3H]thymidine incorporation assay demonstrated that nontoxic doses of CHD have an inhibitory effect on DNA synthesis and suppress cell cycle progression of HUVECs. CHD treatment led to a marked induction of NO production through up-regulation of NOS mRNA expression in a dose- and time-dependent manner, whereas it suppressed VCAM-1 expression. CHD inhibition of VCAM-1 expression was totally blocked by pretreatment with the NO synthesis inhibitor L-NMMA, whereas pretreatment with the NO donor DETA-NO further decreased VCAM-1 level in CHD-treated HUVECs, indicating that VCAM-1 regulation by CHD is mediated through increased NO synthesis by CHD. In addition, TNF-alpha-mediated VCAM-1 activation was substantially impeded by CHD treatment. Collectively, our data suggest that anti-inflammatory or anti-hyperlipidemic effects of CHD might be associated with its ability to activate NO production and suppress VCAM-1 expression in human endothelial cells.  相似文献   

17.
Aberrant chromatin regulation is a frequent driver of leukemogenesis. Mutations in chromatin regulators often result in more stem-like cells that seed a bulk leukemic population. Inhibitors targeting these proteins represent an emerging class of therapeutics, and identifying further chromatin regulators that promote disease progression may result in additional drug targets. We identified the chromatin-modifying protein CHD8 as necessary for cell survival in a mouse model of BCR-Abl+ B-cell acute lymphoblastic leukemia. This disease has a poor prognosis despite treatment with kinase inhibitors targeting BCR-Abl. Although implicated as a risk factor in autism spectrum disorder and a tumor suppressor in prostate and lung cancer, the mechanism of CHD8’s activity is still unclear and has never been studied in the context of hematopoietic malignancies. Here we demonstrate that depletion of CHD8 in B-ALL cells leads to cell death. While multiple B cell malignancies were dependent on CHD8 expression for survival, T cell malignancies displayed milder phenotypes upon CHD8 knockdown. In addition, ectopic expression of the Notch1 intracellular domain in a T cell malignancy partially alleviated the detrimental effect of CHD8 depletion. Our results demonstrate that CHD8 has a context-dependent role in cell survival, and its inhibition may be an effective treatment for B lymphoid malignancies.  相似文献   

18.
Glioblastoma, one of the common malignant brain tumors, results in the highly death, but its underlying molecular mechanisms remain unclear. Smurf1, a member of Nedd4 family of HECT-type ligases, has been reported to contribute to tumorigenicity through several important biological pathways. Recently, it was also found to participate in modulate cellular processes, including morphogenesis, autophagy, growth, and cell migration. In this research, we reported the clinical guiding significance of the expression of Smurf1 in human glioma tissues and cell lines. Western blotting analysis discovered that the expression of Smurf1 was increased with WHO grade. Immunohistochemistry levels discovered that high expression of Smurf1 is closely consistent with poor prognosis of glioma. In addition, suppression of Smurf1 can reduce cell invasion and increase the E-cadherin expression, which is a marker of invasion. Our study firstly demonstrated that Smurf1 may promote glioma cell invasion and suppression of the Smurf1 may provide a novel treatment strategy for glioma.  相似文献   

19.
Glioblastoma multiforme (GBM) is an intracranial tumor; the feature is higher malignant and poorer prognosis. The search for therapeutic targets for gliomas has always been a focus of research in the field of neurology. The unusual expression of epithelial membrane protein 1 (EMP1) has been proved in most tumors. In our study, we determined the expression level of EMP1 expression in glioma tissues. There were higher levels of EMP1 in glioma tissues—particularly GBM tissues—than those in normal brain tissues. Then we discovered that silencing EMP1 inhibited glioma cell invasion and proliferation through inhibiting the PI3K-AKT signaling pathway. Subsequently, we investigated the function of EMP1 on glioma stem cells and found that it regulates the expression of CD44 in such cells to promote stemness. Taken together, the new strategies for the treatment of glioma may be provided by these finding, thereby improving the prognosis associated with it.  相似文献   

20.
Chromodomain helicase/ATPase DNA-binding protein 1-like gene (CHD1L) has been characterized to be a driver gene in hepatocellular carcinoma (HCC). However, the intrinsic connections between CHD1L and intestinal dysbacteriosis-related inflammation reaction in HCC progression remain incompletely understood. In this study, a specific correlation between CHD1L and nonmuscle isoform of myosin light chain kinase (nmMLCK/nmMYLK), a newly identified molecule associated NF-κB signaling transduction, was disclosed in HCC. CHD1L promotes nmMYLK expression and prevents lipopolysaccharide (LPS) induced tumor cell death. In vitro experiment demonstrated that overexpressed nmMYLK is essential for CHD1L to maintain HCC cell alive, while knocking down nmMYLK significantly attenuate the oncogenic roles of CHD1L. Mechanism analysis revealed that nmMYLK can prevent Caspase-8 from combining with MyD88, an important linker of TLRs signaling pathway, while, knocking down nmMYLK facilitate the MyD88 combines with Caspase-8 and lead to the proteolytic cascade of Caspase as well as the consequent cell apoptosis. Mechanism analysis showed that CHD1L promotes the nmMYLK expression potentially through upregulating the heterogeneous nuclear ribonucleoproteins A2/B1 (hnRNP A2/B1) expression, which can bind to myosin light chain kinase (MYLK) pre-mRNA and lead to the regnant translation of nmMYLK. In summary, this work characterizes a previously unknown role of CHD1L in preventing LPS-induced tumor cell death through activating hnRNP A2/B1-nmMYLK axis. Further inhibition of CHD1L and its downstream signaling could be a novel promising strategy in HCC treatment.Subject terms: Cancer microenvironment, Apoptosis, Liver cancer  相似文献   

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