Lovastatin and phenylacetate induce apoptosis, but not differentiation, in human malignant glioma cells

Induction of differentiation is an attractive approach to the management of infiltrative tumors such as malignant glioma. Here, we report that lovastatin and phenylacetate induce apoptosis, but fail to induce differentiation, in malignant glioma cell lines and untransformed rat astrocytes. Lovastatin and phenylacetate promote p21 accumulation but fail to induce cell cycle arrest. BCL-2 gene transfer inhibits apoptosis induced by lovastatin but not apoptosis induced by phenylacetate. Wild-type p53 gene transfer promotes lovastatin-induced apoptosis in p53 wild-type LN-229 cells but not in p53 mutant T98G cells. Phenylacetate-induced apoptosis is attenuated by wild-type p53 gene transfer in both cell lines. Neither lovastatin nor phenylacetate modulate glioma cell sensitivity to CD95 ligand-induced apoptosis or cancer chemotherapy. Thus, this study provides no rationale for clinical trials of lovastatin or phenylacetate in the differentiation therapy of malignant glioma. We conclude that neoplastic glioma cells as well as untransformed rat astrocytes are refractory to the induction of differentiation by lovastatin and phenylacetate.     

脂质体介导CD基因转染SHG-44胶质瘤细胞凋亡的实验研究

目的以含胞嘧啶脱氨酶（CD）基因的pCMVCD重组表达质粒转染SHG-44胶质瘤细胞，体外观察5-氟胞嘧啶（5-FC）对转染CD基因的胶质瘤细胞的凋亡诱导作用。方法体外扩增、酶切鉴定pCMVCD质粒并采用DNA序列测定pCMVCD质粒中的CD基因；脂质体Lipofectamine 2000介导pCMVCD质粒转染SHG-44细胞，G418筛选培养获取抗性细胞克隆（即SHG-44／CD细胞）；免疫细胞化学检测SHG-44／CD细胞的CD基因蛋白水平表达；流式细胞仪、TUNEL实验及透射电子显微镜观察5-FC对表达CD基因的SHG-44／CD细胞凋亡的诱导作用。结果含CD基因的pCMVCD质粒成功转染进入SHG-44细胞，获取了含CD基因的SHG-44／CD细胞，免疫细胞化学染色显示SHG-44／CD细胞成功地表达了CD。在含5-FC的培养液中培养，SHG-44／CD细胞出现典型的凋亡形态，TUNEL显示凋亡细胞比例极高；透射电镜可见凋亡改变；流式细胞术检测凋亡率达18．6％，凋亡率呈剂量依赖性。结论建立了SHG-44恶性人脑胶质瘤细胞的CD／5-FC自杀基因系统。诱导SHG-44／CD胶质瘤细胞产生凋亡可能是脑胶质瘤CD基因疗法的重要机制。     

EGFR反义RNA抑制人脑恶性胶质瘤细胞增殖并诱导凋亡的研究

目的:研究表皮生长因子受体(EGFR)反义RNA对抑制胶质瘤细胞增殖及诱导凋亡的作用。方法:将互补于EGFR 3′端部分序列的反义cDNA转染胶质瘤细胞,检测其生长率、增殖活性、EGFR mRNA及其蛋白表达和细胞凋亡。结果:胶质瘤细胞转染EGFR反义RNA后生长率及增殖活性下降,EGFRmRNA及蛋白表达减低,出现大量细胞凋亡。结论:EGFR有可能成为胶质瘤基因治疗的候选基因。     

重组腺病毒介导P21WAF1/CIP1过量表达治疗人脑胶质瘤的实验研究

目的 研究基因转移P21^WAF1/CIP1过量表达对人脑胶质瘤细胞凋亡的影响和治疗作用。方法 本文构建缺陷型重组腺病毒载体：在CMV启支子控制下的人P21 cDNA（Ad-P21），其编码入P21蛋白。通过渡式细胞仪、RT－PCR进行P21表达检测；应用TUNEL法、免疫组化荧光显微镜和流式细胞仪进行相关凋亡检测、分析。结果 RT－PCR检测五株亲本胶质瘤细胞表达P21^WAF1/CIP1 cDNA，而流式细胞仪未检测到P21表达；Ad-P21转导的胶质瘤细胞株均过量表达P21；在体内外Ad-P21能诱导胶质细胞瘤向终末分化、凋亡或诱导炎症反应抑制肿瘤生长或消退。结论 基因转移P21^WAF1/CIP1为研究基因治疗恶性脑胶质瘤提供了有效的手段。     

海葵毒素对神经胶质瘤细胞的凋亡诱导作用

目的 研究从海葵组织中提取的海葵毒素(Phyllodiscus semonii toxin,PsTX)对人神经胶质瘤细胞(U251)凋亡的诱导作用及其可能机制.方法 MTT法检测PsTX对肿瘤细胞的增殖抑制率;原位末端脱氧核糖苷肽转移酶分析法(TUNEL)及DNA Ladder法检测PsTX对肿瘤细胞的凋亡诱导作用;免疫组织化学染色显示Fas蛋白在U251细胞中的表达.结果 PsTX对人神经胶质瘤细胞具有明显的生长抑制及促凋亡作用,PsTX诱导Fas在人神经胶质瘤细胞膜上表达增高.结论 PsTX可能通过Fas途径诱导人神经胶质瘤细胞凋亡.     

The failure of current immunotherapy for malignant glioma. Tumor-derived TGF-β, T-cell apoptosis, and the immune privilege of the brain

Human malignant gliomas are rather resistant to all current therapeutic approaches including surgery, radiotherapy and chemotherapy as well as antibody-guided or cellular immunotherapy. The immunotherapy of malignant glioma has attracted interest because of the immunosuppressed state of malignant glioma patients which resides mainly in the T-cell compartment. This T-cell suppression has been attributed to the release by the glioma cells of immunosuppressive factors like transforming growth factor-β (TGF-β) and prostaglandins. TGF-β has multiple effects in the immune system, most of which are inhibitory. TGF-β appears to control downstream elements of various cellular activation cascades and regulates the expression of genes that are essential for cell cycle progression and mitosis. Since TGF-β-mediated growth arrest of T-cell lines results in their apoptosis in vitro, glioma-derived TGF-β may prevent immune-mediated glioma cell elimination by inducing apoptosis of tumor-infiltrating lymphocytes in vivo. T-cell apoptosis in the brain may be augmented by the absence of professional antigen-presenting cells and of appropriate costimulating signals. Numerous in vitro studies predict that tumor-derived TGF-β will incapacitate in vitro-expanded and locally administered lymphokine-activated killer cells (LAK-cells) or tumor-infiltrating lymphocytes. Thus, TGF-β may be partly responsible for the failure of current adoptive cellular immunotherapy of malignant glioma. Recent experimental in vivo studies on non-glial tumors have corroborated that neutralization of tumor-derived TGF-β activity may facilitate immune-mediated tumor rejection. Current efforts to improve the efficacy of immunotherapy for malignant glioma include various strategies to enhance the immunogenicity of glioma cells and the cytotoxic activity of immune effector cells, e.g., by cytokine gene transfer. Future strategies of cellular immunotherapy for malignant glioma will have to focus on rendering glioma cell-targeting immune cells resistent to local inactivation and apoptosis which may be induced by TGF-β and other immunosuppressive molecules at the site of neoplastic growth. Cytotoxic effectors targeting Fas/APO-1, the receptor protein for perforin-independent cytotoxic T-cell killing, might be promising, since Fas/APO-1 is expressed by glioma cells but not by untransformed brain cells, and since Fas/APO-1-mediated killing in vitro is not inhibited by TGF-β.     

Overexpression of immediate early gene X‐1 (IEX‐1) enhances γ‐radiation‐induced apoptosis of human glioma cell line,U87‐MG

Malignant gliomas are usually incurable even if adjuvant therapy is delivered after neurosurgical treatment. Therefore, to enhance their radiation‐induced apoptosis, it is important to detect the mechanism(s) leading to the death of malignant glioma cells. We report that apoptosis was induced in a time‐dependent manner after γ‐radiation and that irradiated U87‐MG cells (human glioblastoma cell line) expressed immediate early gene X‐1 (IEX‐1) with p53. We also document that their apoptotic sensitivity to γ‐radiation was enhanced by the overexpression of IEX‐1. Our findings suggest that IEX‐1 may represent a new factor for the enhancement of radiation‐induced apoptosis of human glioma cells.     

胞嘧啶脱氨酶自杀基因转染U251恶性脑胶质瘤细胞及其表达研究

目的探讨胞嘧啶脱氨酶（CD）自杀基因转染U251恶性脑胶质瘤细胞的方法及其表达效果。方法采用脂质体法将CD基因转染U251恶性脑胶质瘤细胞，G418筛选阳性克隆（U251-CD），采用RT—PCR、免疫细胞化学染色、流式细胞仪（FCM）凋亡分析和高效液相色谱（HPLC）等方法检测CD基因的表达及其功能。结果CD基因成功转染U251细胞。G418筛选获得阳性克隆．RT—PCR证实阳性细胞有CD基因表达，抗-CD-抗体免疫细胞化学法显示细胞浆染色阳性．U251-CD细胞加入5-氟胞嘧啶（5-FC）后，FCM显示细胞凋亡峰，HPLC可检测到5-FC培养液内有5-氟尿嘧啶（5-FU）产生。结论CD基因能够在U251细胞表达．并具备将5—Fc转变为5-Fu的功能，造成肿瘤细胞凋亡．CD-5-FC系统可作为恶性脑胶质瘤辅助治疗手段之一。     

Expression and functional activity of osteoprotegerin in human malignant gliomas

Apo2L/TRAIL-based therapy is a promising experimental approach to the treatment of human malignant gliomas. Osteoprotegerin (OPG) is a soluble decoy receptor for Apo2L/TRAIL that antagonizes Apo2L/TRAIL-induced apoptosis. High levels of OPG expressed by tumor cells might therefore abrogate the activity of exogenously added or adenovirally expessed Apo2L/TRAIL. Here we assessed the expression of OPG in human gliomas in vivo, in primary glioma cell cultures and in established glioma cell lines. Immunohistochemistry revealed weak OPG immunoreactivity in up to 5% of the tumor cells in 8 of 13 glioblastomas. Strong OPG labeling was detected in single scattered tumor cells in one of these specimens. Five glioblastomas did not express OPG. High OPG expression was found in 1 of 6 primary glioma cell cultures and in 1 of 12 established glioma cell lines, T98G. OPG released by T98G cells was biologically active in that it inhibited Apo2L/TRAIL-induced apoptosis in sensitive glioma cells. Altogether, however, these data suggest that OPG expression may not be a major pathway of glioma cell resistance to future Apo2L/TRAIL-based therapeutic approaches.     

小干扰RNA沉默RHBDF1基因抑制胶质瘤细胞生长和诱导细胞凋亡的初步研究

目的 检测RHBDF1基因在正常胶质细胞和胶质瘤细胞内的表达,以及小干扰RNA沉默C6胶质瘤细胞内RHBDF1基因后是否诱导C6细胞凋亡和抑制细胞生长,为基因治疗胶质瘤寻找新的靶基因. 方法采用Western blot检测RHBDF1基因在正常胶质细胞和胶质瘤细胞(包括C6、U251和MGR2)的表达情况:用脂质体转染法分别将RHBDF1 siRNA或对照siRNA转染入C6细胞内,RT-PCR和Western blot方法检测siRNA转染后对C6细胞内RHBDF1基因和蛋白的影响;Tune1法检测RHBDF1基因沉默后对细胞凋亡的诱导情况,Ki-67免疫荧光染色观察RHBDF1基因沉默后对细胞生长抑制的影响.结果 与正常胶质细胞比较,胶质瘤细胞内RHBDF1基因存在着过度表达.siRNA转染入C6细胞后.对照siRNA组凋亡率为2.96%±1.25%,而RHBDF1siRNA1组和RHBDF1 siRNA2的凋亡率分别为36.35%±4.85%和33.58%±4.08%:对照siRNA组细胞增殖率为95.96%±3.25%,而RHBDF1 siRNA1组和RHBDF1 siRNA2组的细胞增殖率分别为24.57%±5.53%和25.68%±4.08%;组间细胞凋亡率和增殖率比较差异均有统计学意义(P<0.05).结论 RHBDF1基因在胶质瘤细胞内存在过度表达,沉默该基因后可以诱导细胞凋亡和抑制细胞生长,RHBDF1基因可能成为基因治疗胶质瘤的一个新的靶基因.     

RNAi下调PIK3 CB表达抑制U251胶质瘤细胞生长的体内外研究

目的 探讨应用RNAi技术靶向磷酸肌醇酯-3-激酶β催化亚单位(PIK3CB)抑制恶性胶质瘤细胞系U251的PIK3CB表达后在体内外对U251细胞生长抑制作用.方法 将短发夹RNA(shRNA)表达载体psiRNA-PIK3CB进行脂质体介导的U251人脑恶性胶质瘤细胞系表达,检测细胞转染前后的细胞增殖能力和凋亡的变化.应用裸鼠皮下荷瘤模型观察脂质体介导shRNA基因治疗对U251细胞生长抑制作用,对肿瘤组织应用免疫荧光双染色和免疫组化的方法分析结果.结果 靶向PIK3CB的shRNA转染后U251细胞生长受到抑制,细胞周期出现G2/M阻滞,细胞明显凋亡.裸鼠皮下荷瘤模型实验显示psiRNA-PIK3CB显著抑制皮下肿瘤生长(P＜0.01).结论 靶向PIK3CB的shRNA基因治疗可以成为胶质瘤治疗的新策略.     

Macrophage migration inhibitory factor (MIF) expression in human malignant gliomas contributes to immune escape and tumour progression

Macrophage migration inhibitory factor (MIF), which inhibits apoptosis and promotes angiogenesis, is expressed in cancers suppressing immune surveillance. Its biological role in human glioblastoma is, however, only poorly understood. We examined in-vivo expression of MIF in 166 gliomas and 23 normal control brains by immunohistochemistry. MIF immunoreactivity was enhanced in neoplastic astrocytes in WHO grade II glioma and increased significantly in higher tumour grades (III–IV). MIF expression was further assessed in 12 glioma cell lines in vitro. Quantitative RT-PCR showed that MIF mRNA expression was elevated up to 800-fold in malignant glioma cells compared with normal brain. This translated into high protein levels as assessed by immunoblotting of total cell lysates and by ELISA-based measurement of secreted MIF. Wild-type p53-retaining glioma cell lines expressed higher levels of MIF, which may be connected with the previously described role of MIF as a negative regulator of wild-type p53 signalling in tumour cells. Stable knockdown of MIF by shRNA in glioma cells significantly increased tumour cell susceptibility towards NK cell-mediated cytotoxicity. Furthermore, supernatant from mock-transfected cells, but not from MIF knockdown cells, induced downregulation of the activating immune receptor NKG2D on NK and CD8⁺ T cells. We thus propose that human glioma cell-derived MIF contributes to the immune escape of malignant gliomas by counteracting NK and cytotoxic T-cell-mediated tumour immune surveillance. Considering its further cell-intrinsic and extrinsic tumour-promoting effects and the availability of small molecule inhibitors, MIF seems to be a promising candidate for future glioma therapy.     

人突变型TRAIL体外诱导脑恶性胶质瘤细胞凋亡的研究

目的观察人突变型肿瘤坏死因子相关的凋亡诱导配体(TRAIL)体外诱导人脑胶质瘤细胞的凋亡作用。方法设计90个碱基突变的人TRAIL全长基因,分四段合成,然后拼接获得全长寡核苷酸,插入原核表达载体pGEX-2T,转化E.coliDH-5α,丙基硫代-β-D-半乳糖苷(IPTG)诱导表达,亲和层析法分离、纯化融合蛋白,凝血酶切得到单纯的TRAIL蛋白。MTT法和流式细胞仪定量分析纯化产物体外对人A172、U87、U251和鼠C6脑恶性胶质瘤细胞的凋亡作用。结果突变型TRAIL原核表达产物为可溶性,体外可明显诱导人A172、U87、U251脑胶质瘤细胞凋亡,而对C6鼠胶质瘤细胞无明确的凋亡诱导作用。结论原核表达突变型TRAIL在体外具有明显诱导脑胶质瘤细胞凋亡的作用。     

PTEN-反义AKT2联合基因治疗胶质瘤的体内外实验研究

目的研究PTEN-反义AKT2的联合基因治疗在动物体内、体外抑制脑胶质瘤生长的效果。方法将大鼠C6胶质瘤细胞进行PTEN-反义AKT2的共转染,进行了原位杂交等体外实验研究,并进行了大鼠的体内实验研究。结果PTEN与反义AKT2共转染在体外可以产生比较明显的协同作用,在体内实验中,对照组和空载组大鼠均于3周内死亡;转染组8只大鼠和治疗组7只大鼠观察60d内无自然死亡。结论PTEN-反义AKT2联合基因治疗可以产生明显的协同作用,与单一治疗效果相比抑瘤作用明显增强,可以作为联合基因治疗的候选基因组合。     

EphA2、EphrinA1表达与脑胶质瘤恶性表型的关系

目的 探讨酪氨酸激酶受体EphA2和其配体EphrinA1表达与脑胶质瘤恶性表型的关系,为发现恶性脑胶质瘤治疗新靶点提供理论依据.方法 构建针对EphA2的RNAi载体pSilencer-EphA2-SR质粒并转染U251、U87和SHG44细胞,应用Western blotting检测转染后细胞EphA2、EphrinA1的表达,MTT法和软琼脂克隆形成实验检测细胞增殖能力的变化,体外侵袭实验和流式细胞仪分别检测细胞侵袭和凋亡的变化;建立U251、U87和SHG44细胞的裸鼠胶质瘤移植模型,分别于瘤内注射脂质体+pSilencer空载体或脂质体+pSilencer-EphA2-SR质粒,30d后比较移植瘤的平均体积和质量,免疫组化染色检测移植瘤组织EphA2和EphrinA1的表达.结果 成功构建EphA2 RNAi载体pSilencer-EphA2-SR质粒.转染pSilencer-EphA2-SR后48 h Western blotting结果显示3种细胞EphA2表达水平均降低,而EphrinA1表达水平升高;MTT、软琼脂克隆形成实验、体外侵袭实验结果显示3种细胞的A值、克隆形成率、侵袭率均低于转染pSilencer空载体者,差异有统计学意义(P＜0.05);而流式细胞仪检测显示3种细胞的凋亡率均高于转染pSilencer空载体者,差异有统计学意义(P＜0.05).瘤内注射脂质体+pSilencer-EphA2-SR质粒后移植瘤的体积和重量均低于注射脂质体+pSilencer空载体者,差异有统计学意义(P＜0.05).免疫组化染色显示瘤内注射脂质体+pSilencer-EphA2-SR质粒后EphA2表达降低,EphrinA1表达水平升高,瘤内注射脂质体+pSilencer空载体后二者的表达无明显变化.结论 EphA2、EphrinA1是脑胶质瘤恶性表型的重要调控分子,干扰EphA2分子可显著上调EphrinA1表达、部分逆转胶质瘤细胞恶性表型,提示EphA2、EphrinA1有望成为脑胶质瘤治疗新靶点.

Abstract：

Objective To investigate the relation between altered expressions of EphA2 receptor tyrosine kinase and its ligand EphrinA1 and malignant phenotype of glioma cells, and explore the new targeting molecule for treating malignant gliomas. Methods The RNAi vector (plasmid pSilencer-EphA2-SR) against EphA2 was constructed and transfected into the malignant glioma cells (U251, U87 and SHG44). Forty-eight h after the transfection, the expressions of EphA2 and EphrinA1 were detected by Western blotting; the viability and anchorage independence of the glioma cells were observed by MTT assay and colony formation assay; the invasion viability and apoptosis of glioma cells were observed by modified Boyden chamber assay and flow cytometry. Glioma xenograft models were established in nude mice; plasmid pSilencer-EphA2-SR or pSilencer-null mixed with lipofectamine was intratumorally injected. The average tumor volume and weight of the transplanted gliomas were measured and compared; the expressions of EphA2 and EphrinA1 were detected by immunohistochemical staining.Results The RNAi plasmid against EphA2 was successfully constructed. After the transfection of plasmid pSilencer-EphA2-SR, the expression of endogenous EphA2 was suppressed, which consequently resulted in increased EphrinA1 level. As compared with cells of the plasmid pSilencer-null group, cells of the plasmid pSilencer-EphA2-SR group showed obviously decreased cell viability, anchorage independence rate and in vitro invasion ability, but significantly increased cell apoptosis rate (P＜0.05).Furthermore, suppression of EphA2 resulted in delayed tumor growth and increased EphrinA 1 expression in mice xenografts. Conclusion EphA2 and EphrinA1 may be key coupled-regulators for malignant phenotype of glioma cells. EphA2 suppression partially reverses the malignant phenotype of aggressive gliomas, possibly through up-regulating the EphrinA1 expression, which indicates that EphA2 and EphrinA1 might become the new targeting molecule for treatment of gliomas.     

Dendritic cell therapy for malignant glioma]

Despite advances in radiation and chemotherapy along with surgical resectioning, the prognosis of patients with malignant glioma is poor. Among the new treatments currently being investigated for malignant glioma, immunotherapy is theoretically very attractive, since it offers the potential for high tumor-specific cytotoxicity. There are increasing reports demonstrating that systemic immunotherapy using dendritic cells is capable of inducing an antiglioma response. Therefore, dendritic cell-based immunotherapy could be a new treatment modality for patients with glioma. Dendritic cell-based immunotherapy strategies appear promising as an approach to successfully induce an antitumor immune response and increase survival in patients with glioma. The development of methods for manipulating dendritic cells for the purpose of vaccination will enhance the clinical usefulness of these cells for biotherapy for malignant glioma.     

Epigallocatechin-3-gallate induces apoptosis,inhibits proliferation and decreases invasion of glioma cell

Epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, has been considered a potential therapeutic and chemopreventive agent for cancer. Glioma is a malignant tumor with high mortality but effective therapy has not yet been developed. In this study, we found that EGCG induced apoptosis in U251 glioma cells via the laminin receptor (molecular weight 67kDa) in a time- and dose-dependent manner, decreased their invasiveness and inhibited their proliferation. The mitogen-activated protein kinase pathway was shown to be involved in glioma cell apoptosis and proliferation. Furthermore, the mRNA levels of matrix metalloproteinase (MMP)-2 and MMP-9 were reduced after EGCG treatment. These results suggest that EGCG has important therapeutic effects with low toxicity and side-effects, and could be used in cancer chemoprevention.     

Nucleoside analogs in the treatment of primary malignant brain tumors

Standard therapeutic modalities including surgery, radio- and/or peripheral chemotherapy are ineffective in malignant gliomas. This is due to infiltration of distant brain areas by glioma cells and to the blood-brain barrier limiting penetration of anticancer drugs. One of the most promising experimental methods of glioma therapy is intracerebral implantation of biodegradable polymers containing cytotoxic compounds. This method allows to avoid peripheral toxicity of drugs. Considering that practically it is only malignant cells that proliferate in the brain, the use of drugs displaying selective toxicity toward DNA-replicating cells might help to avoid central toxicity as well. Several nucleoside analogs display selective cytotoxic and/or radiosensitizing effects on proliferating cells. Despite encouraging results obtained in the in vitro and animal models of gliomas, peripheral administration of these drugs turned out to be ineffective in the clinical settings. Intracerebral implantation of nucleoside analogs-containing biodegradable polymers may be much more efficacious, especially when combined with radiotherapy. Appropriate nucleoside analogs may also be employed in cell-selective radiotherapy and gene therapy of malignant gliomas.     

声动力化学疗法促大鼠脑胶质瘤细胞凋亡及抗血管作用的实验研究

目的探讨声动力化学疗法(SDT)对大鼠脑胶质瘤细胞凋亡及微血管蛋白表达的关系。方法以大鼠颅内C6胶质瘤为实验模型,观察4组(SDT、US、HMME、对照)处理后脑胶质瘤原位细胞凋亡、Cyt-C蛋白、Caspase-3蛋白表达水平。结果原位凋亡检查见HMME组和对照组凋亡细胞极少,各时间点凋亡率无明显差别。处理后24h,US组凋亡率高于HMME组和对照组;处理后3d、7d,凋亡率与HMME组和对照组无明显差别。SDT组处理后24h,凋亡率明显高于其它3组。处理后3d、7d,凋亡率与其它3组无明显差别。HMME组和对照组各时间点MVD密度、VEGF蛋白表达无明显差别。US组处理后24h,MVD密度、VEGF蛋白表达与HMME组和对照组比较,略下降;处理后3d、7d,2项表达结果与HMME组和对照组无明显差别。SDT组处理后24h MVD密度、VEGF蛋白表达较其它3组明显下降;处理后3d,二者有所升高,但仍较其它3组低;处理后7d,VEGF表达结果与其它3组无明显差别。结论 SDT处理后早期可通过血管靶向作用促进体内胶质瘤细胞凋亡。     

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