Amphiregulin is a factor for resistance of glioma cells to cannabinoid‐induced apoptosis

Gliomas, one of the most malignant forms of cancer, exhibit high resistance to conventional therapies. Identification of the molecular mechanisms responsible for this resistance is therefore of great interest to improve the efficacy of the treatments against these tumors. Δ9‐Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer, including glioma, an effect that relies, at least in part, on the ability of these compounds to induce apoptosis of tumor cells. By analyzing the gene expression profile of two sub‐clones of C6 glioma cells with different sensitivity to cannabinoid‐induced apoptosis, we found a subset of genes with a marked differential expression in the two sub‐clones. Furthermore, we identified the epidermal growth factor receptor ligand amphiregulin as a candidate factor to mediate the resistance of glioma cells to cannabinoid treatment. Amphiregulin was highly overexpressed in the cannabinoid‐resistant cell line, both in culture and in tumor xenografts. Moreover, in vivo silencing of amphiregulin rendered the resistant tumors xenografts sensitive to cannabinoid antitumoral action. Amphiregulin expression was associated with increased extracellular signal‐regulated kinase (ERK) activation, which mediated the resistance to THC by blunting the expression of p8 and TRB3—two genes involved in cannabinoid‐induced apoptosis of glioma cells. Our findings therefore identify Amphirregulin as a factor for resistance of glioma cells to THC‐induced apoptosis and contribute to unraveling the molecular bases underlying the emerging notion that targeted inhibition of the EGFR pathway can improve the efficacy of antitumoral therapies. © 2009 Wiley‐Liss, Inc.     

Lipid composition of human malignant brain tumors

Malignant transformation is characterized by the uncontrolled proliferation of cells. And changes in the composition of glycolipids, cell surface component which may be involved in regulation of cell growth, were often observed in the malignant transformation. In this study, cholesterol, lipid-bound phosphorus, cerebroside, sulfatide and ganglioside were quantitated in the tissue of 20 human malignant brain tumors (malignant glioma, 8; low grade glioma, 4; metastatic tumor, 7; malignant meningioma, 1). As compared with normal brain, all tumor tissue contained lower cholesterol, sialic acid, cerebroside and sulfatide. Metastatic brain tumor or glioma showed characteristic patterns in the content of ganglioside, cerebroside and sulfatide respectively. The ganglioside patterns of metastatic tumor or glioma contained a greater proportion of structurally simpler gangliosides than normal brain. And in metastatic tumor, GM3 was a major ganglioside. On the contrary, glioma had increased proportion of GM3 and GD3 gangliosides. High grade glioma such as Grade 3-4 contained higher proportion of GM3 and GD3, whereas low grade glioma (Grade 1-2) contained less proportion of GM3 and GD3.     

转染外源性p16基因对恶性胶质瘤生长抑制作用的动物体内实验研究

目的 :探讨p16基因在体内对恶性胶质瘤的生长抑制作用。方法 :将外源性p16基因导入C6 细胞内 ,应用立体定向技术将C6细胞种植于SD大鼠尾状核头部 ,用核磁共振 (MR)扫描技术 ,动态观察颅内肿瘤生长情况。并通过免疫组化、原位杂交和细胞凋亡检测肿瘤细胞的增殖活性。结果 :转染组和治疗组大鼠生存期较对照组明显延长。治疗组肿瘤随时间的延长逐渐缩小。免疫组化显示转染组和治疗组P16蛋白表达明显增强。原位杂交和细胞凋亡检测表明 ,转染组和治疗组大鼠肿瘤细胞增殖活性降低。结论 :p16基因在体内有抑制恶性胶质瘤生长的作用 ;瘤体内注入p16cDNA质粒 脂质体复合物 ,可使肿瘤生长受到明显抑制 ,并使多数肿瘤消失     

NADPH氧化酶调节U251胶质瘤细胞的生长和凋亡

目的 研究NADPH氧化酶(NOX)对U251胶质瘤细胞存活、增殖和凋亡的影响.方法 RT-PCR检测U251胶质瘤细胞系NOX基因的表达.分别使用5、15、25 μmol/LNOX抑制剂DPI及10 mmol/L抗氧化剂Tiron处理U251细胞,24h后alamarBlue法检测U251细胞的增殖,流式细胞术检测细胞内活性氧的产生和U251细胞的凋亡情况,并与正常对照组(不做任何处理的1的U251细胞进行比较.结果 U251细胞系中明显表达NOX4 mRNA.各浓度DPI及10 mmol/Ltiron均能抑制U251胶质瘤细胞的生长,诱导U251细胞凋亡.与正常对照组比较,各浓度DPI处理组的U251细胞内的活性氧簇(ROS)均明显减少,差异有统计学意义(P<0.05); 结论 NOX4可能是胶质瘤细胞内ROS生产的主要来源.NOX4可能通过增加细胞内ROS水平并作用于其下游调节分子,对胶质瘤细胞的生长、存活和凋亡起着重要的调节作用.     

Treatment of rat glioma with a beta-adrenergic agonist and a phosphodiesterase inhibitor in vivo

Rat C 6 glioma is known to possess a beta-adrenergic receptor with which intracellular cyclic adenosine monophosphate (cAMP) levels are altered to control cell growth in vitro. In order to study the effect of beta-adrenergic agonist, isoproterenol, in growth-inhibitory action upon C 6 glioma cells, subcutaneous tumor models and meningeal gliomatisis (MG) models as a brain tumor model have been exposed to the treatment of isoproterenol. Growth of subcutaneous tumor was suppressed by the treatment of the drug, and the survival time of MG rats was prolonged by the intrathecal (i. t.) injection of isoproterenol. The addition of papaverine, phosphodiesterase inhibitor, to the treatment schedule augmented the growth-inhibitory effect of isoproterenol. Therefore, it is concluded that the survival time of the brain tumor models could be prolonged through the inhibition of the growth of C 6 glioma cells by such drugs as those which elevate intracellular cAMP levels.     

M6A去甲基化酶FTO在脑胶质瘤中的表达及其与病人预后的关系

目的 探讨6-甲基腺嘌呤（m6A）去甲基化酶肥胖相关蛋白（FTO）在脑胶质瘤中的表达及其与病人生存预后的关系。方法 选取2015年1月至2017年8月手术切除的脑胶质瘤标本84例（WHOⅡ级24例，Ⅲ级14例，Ⅳ级46例）和颅脑损伤内减压术中获取的非肿瘤脑组织40例为对照。免疫印迹法和免疫组化法检测组织FTO表达水平。胶质瘤病人随访截止2022年8月，计算总生存期。结果 免疫组化染色显示，WHO分级Ⅱ、Ⅲ、Ⅳ级脑胶质瘤组织FTO高表达率分别为20.83%(5/24)、50.00%(7/14)、73.91%(34/46)，均明显高于非肿瘤脑组织[10%(4/40);P<0.05]；而且，WHO分级Ⅳ级胶质瘤FTO过表达率明显高于Ⅱ级胶质瘤（P<0.05）。免疫印迹法检查结果显示脑胶质瘤组织FTO蛋白表达水平明显高于非肿瘤脑组织（P<0.05）。截止随访结束，脑胶质瘤死亡30例，其中高表达组死亡18例，低表达组死亡12例。多因素logistic回归分析显示，FTO高表达是胶质瘤预后不良的独立危险因素（OR=3.794;95%CI 1.164～5.108;P<0.00...     

Neuregulin-1 enhances survival of human astrocytic glioma cells

Malignant astrocytic gliomas, referred to as astrocytomas, represent the most commonly diagnosed adult primary brain tumor. These tumors are characterized by unrelenting growth that is often resistant to chemotherapy and radiation therapy. Tumor expansion into the healthy surrounding brain tissue produces severe and often fatal consequences. In this study, we examine the potential for the neuregulin-1/erbB receptor signaling cascade to contribute to this process by modulating glioma cell growth. Using antibodies specific for the erbB receptors, we demonstrate the expression patterns for the erbB2, erbB3, and erbB4 receptors in human glioma biopsy samples. We then verify receptor expression in a panel of human glioma cell lines. Next, we investigate the status of the erbB2 and erbB3 receptors in the human glioma cell lines and find that they are constitutively tyrosine-phosphorylated and heterodimerized. Subsequently, we demonstrate that theses same cell lines express membrane bound and released forms of neuregulins, the erbB receptor ligands, suggesting a possible autocrine or paracrine signaling network. Furthermore, we show that exogenous activation of erbB2 and erbB3 receptors in U251 glioma cells by recombinant Nrg-1beta results in enhanced glioma cell growth under conditions of serum-deprivation. This enhancement is due to an increase in cell survival rather than an increase in cell proliferation and is dependent on the activation of erbB2 and phosphatidylinositol-3 kinase (PI3K). Moreover, Nrg-1beta activates an inhibitor of apoptosis, Akt, implying a possible role for this kinase in mediating Nrg-1beta effects in gliomas. This data suggests that glioma cells may use autocrine or paracrine neuregulin-1/erbB receptor signaling to enhance cell survival under conditions where growth would otherwise be limited.     

Adrenomedullin and nitric oxide: implications for the etiology and treatment of primary brain tumors

Gliomas, defined as tumors of glial origin, represent between 2-5 percent of all adult cancer and comprise the majority of primary brain tumors. Infiltrating gliomas, with an incidence of more than 40 percent of brain tumors, are the most common and destructive primary brain tumors for which conventional therapies have not significantly improved patient outcome. In fact, patients suffering from malignant gliomas have poor prognoses and the majority have local tumor recurrence after treatment. Tumor growth and spread of tumor cells depend basically upon angiogenesis and on functional abnormalities of tumor cells in the control of apoptosis, as they are paradigmatic for their intrinsic resistance to multiple pro-apoptotic stimuli. Therefore, promising strategies for treatment of brain cancer would be directed to appropriate neutralization of angiogenesis and sensibilization of cancer cells to undergo apoptosis. However, despite advances in this field, high-grade gliomas remain incurable with survival often measured in months. Therefore there is a need to discover new and more potent cocktails of drugs to target the key molecular pathways involved in glioma angiogenesis and apoptosis. This review deals with the effects of two groups of molecules closely linked to neural tissue, which have been implicated in brain cancer: nitric oxide and peptides of the adrenomedullin family. These molecules exert vasodilatory and proangiogenic actions. Adrenomedullin also has antiapoptotic functions at appropriate concentrations. The inhibition of these functions, in the case of cancer, may provide new pharmacological strategies in the treatment of this disease.     

Perinuclear leucine-rich repeats and immunoglobulin-like domain proteins (LRIG1-3) as prognostic indicators in astrocytic tumors

We have previously characterized three human leucine-rich repeats and immunoglobulin-like domains (LRIG) genes and proteins, named LRIG1-3 and proposed that they may act as suppressors of tumor growth. The LRIG1 transmembrane protein antagonizes the activity of epidermal growth factor receptor family receptor tyrosine kinases. In this study, we evaluated the mRNA expression level of LRIG1-3 in human glioma cell lines and control-matched glioma tissues, characterized the sub-cellular localization of an LRIG3–GFP fusion protein, and analyzed the relationship between sub-cellular localization of LRIG1-3 and clinical parameters in 404 astrocytic tumors by immunohistochemistry. LRIG1-3 mRNA was detected in all human glioma cell lines and matched glioma samples, with large differences in the expression levels. Ectopically expressed LRIG3–GFP localized to perinuclear and cytoplasmic compartments, and to the cell surface of transfected glioma cells. Perinuclear staining of LRIG1-3 was associated with low WHO grade and better survival of the patients. Perinuclear staining of LRIG3 was associated with a lower proliferation index and was in addition to tumor grade, an independent prognostic factor. Furthermore, within the groups of grade III and grade IV tumors, perinuclear staining of LRIG3 significantly correlated with better survival. These results indicate that expression and sub-cellular localization of LRIG1-3 might be of importance in the pathogenesis and prognosis of astrocytic tumors.     

Expression of the proteolytic factors, tPA and uPA, PAI-1 and VEGF during malignant glioma progression.

Various proteases and their inhibitors have been shown to be important in tumor invasion. Angiogenesis is further a prerequisite for the growth and progression of solid tumors. Since these systems are functionally linked, in situ hybridization and in situ zymography were used to investigate the spatial and temporal expression of factors representative of the plasmin/plasminogen system and of an angiogenic factor in the BT4C glioma model. This tumor is invasive with a high grade of neovascularization. Tissue-type plasminogen activator urokinase-type plasminogen activator and plasminogen activator inhibitor-1 mRNA were expressed in glioma cells during the entire tumor growth. Early in the tumor development the expression was found throughout the small tumor (approximately 10 mm3) while later in the time course the expression was found predominantly in the invasive tumor border of the tumor. The in situ zymography demonstrated that the plasminogen activators were translated into functional proteins. Vascular endothelial growth factor mRNA was expressed following a similar spatial and temporal pattern with an early expression in the entire small tumor while later, in larger tumors, it was exclusively expressed in the invasive tumor edge. In normal brain, the ventricular ependyma, meninges, as well as scattered neurons expressed tissue-type plasminogen activator mRNA. Vascular endothelial growth factor mRNA was observed in the choroid plexus, and in scattered cells in normal brain tissue. Our finding may suggest a functional co-operation of tissue-type plasminogen activator, urokinase-type plasminogen activator, plasminogen activator inhibitor-1 and vascular endothelial growth factor during glioma progression. This model could be of value when evaluating different treatment modalities aimed at blocking the migrating capacity and growth of glial tumors.     

Metalloproteinase disintegrins ADAM8 and ADAM19 are highly regulated in human primary brain tumors and their expression levels and activities are associated with invasiveness

Patients with primary brain tumors have bleak prognoses and there is an urgent desire to identify new markers for sensitive diagnosis and new therapeutic targets for effective treatment. A family of proteins, the disintegrin and metalloproteinases (ADAMs or adamalysins), are cell surface and extracellular multidomain proteins implicated in cell-cell signaling, cell adhesion, and cell migration. Their putative biological and pathological roles make them candidates for promoting tumor growth and malignancy. We investigated the expression levels of 12 cerebrally expressed ADAM genes in human primary brain tumors (astrocytoma WHO grade I-III, glioblastoma WHO grade IV, oligoastrocytoma WHO grade II and III, oligodendroglioma WHO grade II and III, ependymoma WHO grade II and III, and primitive neuroectodermal tumor WHO grade IV) using real-time PCR. The mRNAs of the five ADAMs 8, 12, 15, 17, and 19 were significantly upregulated. The ADAM8 and ADAM19 proteins were mainly located in tumor cells and in some tumors in endothelia of blood vessels. In brain tumor tissue, ADAM8 and ADAM19 undergo activation by prodomain removal resulting in active proteases. By using specific peptide substrates for ADAM8 and ADAM19, respectively, we demonstrated that the proteases exert enhanced proteolytic activity in those tumor specimens with the highest expression levels. In addition, expression levels and the protease activities of ADAM8 and ADAM19 correlated with invasive activity of glioma cells, indicating that ADAM8 and ADAM19 may play a significant role in tumor invasion that may be detrimental to patients survival.     

Geminin表达水平与脑胶质瘤病人预后的关系

目的 探讨Geminin表达水平与脑胶质瘤病人预后的关系。方法 收集2014年1月~2017年1月手术切除并经术后病理证实的脑胶质瘤标本90例,以及因颅脑损伤内减压术切除的非肿瘤脑组织50,采用PCR检测Geminin mRNA表达水平。90例脑胶质瘤根据Geminin mRNA表达水平中位数分为高表达组和低表达组。90例胶质瘤病人随访时间截止2020年1月1日或者病人死亡,随访32~55个月,中位随访时间41个月。结果 随访期间,死亡80例,存活10例。脑胶质瘤组织Geminin mRNA表达水平明显高于非肿瘤脑组织（P<0.05）。多因素Cox比例回归风险模型分析结果显示,Geminin mRNA过表达是脑胶质瘤病人死亡的独立危险因素（HR=1.874;95% CI 1.323-2.295;P=0.043）。Kaplan-Meier生存曲线显示,低表达组中位生存期较高表达组明显延长（P<0.05）。结论 脑胶质瘤Geminin呈高表达,是病人生存预后不良的独立危险因素。     

Bimodal anti‐glioma mechanisms of cilengitide demonstrated by novel invasive glioma models

Integrins are expressed in tumor cells and tumor endothelial cells, and likely play important roles in glioma angiogenesis and invasion. We investigated the anti‐glioma mechanisms of cilengitide (EMD121974), an αvβ3 integrin inhibitor, utilizing the novel invasive glioma models, J3T‐1 and J3T‐2. Immunohistochemical staining of cells in culture and brain tumors in rats revealed positive αvβ3 integrin expression in J3T‐2 cells and tumor endothelial cells, but not in J3T‐1 cells. Established J3T‐1 and J3T‐2 orthotopic gliomas in athymic rats were treated with cilengitide or solvent. J3T‐1 gliomas showed perivascular tumor cluster formation and angiogenesis, while J3T‐2 gliomas showed diffuse single‐cell infiltration without obvious angiogenesis. Cilengitide treatment resulted in a significantly decreased diameter of the J3T‐1 tumor vessel clusters and its core vessels when compared with controls, while an anti‐invasive effect was shown in the J3T‐2 glioma with a significant reduction of diffuse cell infiltration around the tumor center. The survival of cilengitide‐treated mice harboring J3T‐1 tumors was significantly longer than that of control animals (median survival: 57.5 days and 31.8 days, respectively, P < 0.005), while cilengitide had no effect on the survival of mice with J3T‐2 tumors (median survival: 48.9 days and 48.5, P = 0.69). Our results indicate that cilengitide exerts a phenotypic anti‐tumor effect by inhibiting angiogenesis and glioma cell invasion. These two mechanisms are clearly shown by the experimental treatment of two different animal invasive glioma models.     

Expression of antisense bcl-2 cDNA abolishes tumorigenicity and enhances chemosensitivity of human malignant glioma cells

Bcl-2 is a key antiapoptotic protein, and it confers survival advantages on many types of tumors by inhibiting apoptotic cell death. Malignant gliomas are the most common primary central nervous system tumors, but the role of bcl-2 in these tumors has not been defined. We investigated the impact of bcl-2 on malignant gliomas by suppressing its expression. Antisense human bcl-2 cDNA was transfected into human malignant glioma cells. The effects of bcl-2 protein down-regulation on glioma cell morphology, in vitro tumor growth, and tumorigenicity in nude mice, as well as chemosensitivity to cisplatin, were studied. Expression of antisense bcl-2 cDNA decreased bcl-2 protein by more than sixfold. Antisense bcl-2 stable transfectants (AS-bcl-2) showed profound morphological change and markedly retarded cell growth in vitro. Transplantation of AS-bcl-2 cells resulted in no tumor formation, whereas backbone plasmid transfectant control formed tumors in each mouse transplanted. Expression of antisense bcl-2 in glioma cells resulted in significantly increased cytotoxicity of cisplatin. In conclusion, antisense bcl-2 expression can effectively reduce glioma survival, including retarding in vitro growth, complete loss of tumorigenicity, and significantly enhanced cisplatin cytotoxicity. These results suggest that bcl-2 plays an important role in glioma malignancy and chemoresistance. Development of strategies targeted at bcl-2 has the potential to advance treatment for malignant gliomas.     

Annexin A2 promotes glioma cell invasion and tumor progression

Gliomas are highly invasive, lethal brain tumors. Tumor-associated proteases play an important role in glioma progression. Annexin A2 is overexpressed in many cancers and correlates with increased plasmin activity on the tumor cell surface, which mediates degradation of extracellular matrix and promotes neoangiogenesis to facilitate tumor growth. In this study, we used two glioma cell lines, mouse GL261-EGFP and rat C6/LacZ, as well as stable clones transfected with an annexin A2 knockdown construct. We find that the annexin A2 knockdown decreased glioma cell migration in vitro and decreased membrane-bound plasmin activity. In vivo, we injected the glioma cells into the rodent brain and followed glioma progression. Knockdown of annexin A2 in glioma cells decreased tumor size and slowed tumor progression, as evidenced by decreased invasion, angiogenesis, and proliferation, as well as increased apoptosis in the tumor tissue of the annexin A2 knockdown group. Moreover, we report that the levels of expression of annexin A2 in human glioma samples correlate with their degree of malignancy. Together, our findings demonstrate that inhibition of annexin A2 expression in glioma cells could become a new target for glioma therapy.     

肿瘤干细胞致敏的树突状细胞对脑胶质瘤细胞免疫的影响

目的 研究肿瘤干细胞(BTSCs)致敏的树突状细胞(DCs)疫苗对颅内荷瘤小鼠的治疗作用.方法 无血清培养基中加入表皮生长因子和碱性成纤维细胞生长因子,将C6胶质瘤细胞诱导成胶质瘤干细胞,以此致敏大鼠骨髓来源的树突状细胞制备疫苗;立体定向建立大鼠颅内C6胶质瘤模型,分为A、B、C、D四组.每组分别经尾静脉注射1×107BTSCs致敏的DCs(DCs-BTSCs)、1×107 C6胶质瘤细胞致敏的DCs(DCs-C6)、1×107DCs及PBS,Kaplan-Meier法对大鼠生存情况进行分析,大鼠脑组织标本行HE染色及免疫组化分析.结果 胶质瘤干细胞CD133+及nestin染色阳性;DCs具有典型的树突状结构,特异性标志OX62+表达阳性;生存时间A组较其他组明显延长,Log-rank检验差异有统计学意义(P＜0.05);A组HE染色炎性细胞浸润最多,免疫组化可见较多的CD8+T淋巴细胞.结论 肿瘤干细胞致敏的树突状细胞疫苗能明显提高机体对胶质瘤的免疫力,其作用优于胶质瘤细胞致敏的树突状细胞疫苗,为树突状细胞疫苗的临床应用提供了新的依据.

Abstract：

Objective To investigate the effect of dendritic cells pulsed with brain tumor stem cells which are used to treat on intracranial glioma.MethodWe obtained murine brain tumor stem cells by growing C6 cells in epidermal growth factor/basic fibroblast growth factor without serum.Dendritic cells isolated from rat bone marrow were pulsed with BTSCs.Rat brain glioma models were established by stereotactic technique.107 DCs pulsed with BTSCs and C6 were injected through tail vein in group A and group B respectively.The same number of DCs and the same volume PBS were applied to group C and group D.The survival time of rats was analyzed by Log- rank survival analysis.Tumor samples were examinedwithHE staining and immunohistochemistry.Methods BTSCs expressedCD133 + and nestin.DCs appeared typical long dentrite in morphology and expressed OX62+ markers.The survival analysis showed group A was statistically significant in constrast to the other goups (P<0.05).The tumors in group A have the most inflammation and CD8 + T lymphocytes.Concluion DCs loading with BTSCs lysates can provide a higher level of immunity protect against gliomas than those loading with C6 cells,which provide a new method in the immuntherapy of brain glioma.     

Detoxification of oxidative stress in glioma stem cells: Mechanism,clinical relevance,and therapeutic development

Neural oncogenesis is currently incurable and invariably lethal. The development of innovative treatments for this devastating cancer will require a deeper molecular understanding of how cancer cells survive, proliferate, and escape from current therapies. In high‐grade gliomas (HGGs), glioma stem cells (GSCs) may causally contribute to tumor initiation and propagation, therapeutic resistance, and subsequent recurrence of tumors. Within a tumor mass, GSCs are enriched in a hypoxic niche in which the oxidative stress levels are substantially elevated. Paradoxically, however, recent studies suggest that GSCs appear to generate less reactive oxygen species (ROS), a chemical component responsible for elevation of oxidative stress levels. To date, molecular mechanisms for how GSCs reduce oxidative stress to allow preferential survival in hypoxic areas in tumors remains elusive. This review article summarizes recent studies on the role of ROS‐reducing enzymes, including peroxiredoxin 4, in detoxifying oxidative stress preferentially for GSCs in HGGs. In addition, the therapeutic potential of some of the recently identified antioxidant chemotherapeutic agents and avenues for future research in this area are discussed. © 2014 Wiley Periodicals, Inc.