VEGF反义寡核苷酸抑制大鼠胶质瘤生长的时间与剂量的效应关系

目的在大鼠脑内原位注射反义寡核苷酸观察胶质瘤的生长抑制情况的时间与剂量的效应关系。方法所有大鼠均在立体定向导引下右尾状核区接种1×106C6胶质瘤细胞。不同时间和剂量VEGF反义寡核苷酸均在立体定向导引下原穿刺靶点注射。其中实验Ⅰ组在接种细胞的同时原位注射1000μmol/L的VEGF反义寡核苷酸,而实验Ⅱ组则同时注射2000μmol/L的VEGF反义寡核苷酸。对照Ⅰ组为对照。实验Ⅲ和Ⅳ组在细胞接种后的1和2周各原位注射1次,共2次,每次实验Ⅲ组为1000μmol/L、实验Ⅳ组为2000μmol/L的VEGF反义寡苷核酸。对照Ⅱ组为对照。实验V组仅在接种后2周注射1次2000μmol/L的VEGF反义寡核苷酸,并设对照Ⅲ组为对照。实验3周时处死所有的大鼠,解剖出全脑标本,观察肿瘤的生长情况,测量肿瘤大小。结果实验Ⅰ组的抑瘤率为94.5％,实验Ⅱ组的抑瘤率为100％。实验Ⅲ组的抑瘤率为91.5％,实验Ⅳ组为100％,实验Ⅴ组抑瘤率为87.8％。实验组和对照组的肿瘤体积比较有非常显著的差异。结论 原位应用VEGF反义寡核苷酸能取得很好的抗血管生成的治疗效果,抑瘤效果有明显的浓度依赖性。原位早期使用足量反义核酸能取得更好的效果。     

围手术期胶质瘤患者细胞免疫功能的表达

 目的　探讨围手术期胶质瘤患者细胞免疫功能的表达。方法　用免疫荧光技术检测 4 8例胶质瘤患者围手术期T淋巴细胞亚群和NK细胞百分率。结果　胶质瘤患者CD3、CD4 、CD8及CD4 /CD8比值均明显低于对照组 ;肿瘤切除术后细胞免疫功能有所恢复 ,但与术前比较无明显差异 ,且仍低于正常状态。结论　胶质瘤患者细胞免疫功能低下 ,且肿瘤切除术后其细胞免疫功能尚难很快恢复到正常状态 ,临床上应注意围手术期细胞免疫功能的保护。     

X刀治疗大鼠C6脑胶质瘤诱发凋亡及抑癌基因p16蛋白的表达

 目的　为了探讨经X刀照射诱导C6脑胶质瘤凋亡及其抑癌基因p16蛋白的表达。方法　建立大鼠C6脑胶质瘤模型 ,经X刀照射后 ,采用TUNEL法检测细胞凋亡 ,免疫组化SABC方法检测抑癌基因p16蛋白表达的变化。结果　治疗组凋亡阳性细胞数明显高于对照组 (P <0 .0 5 ) ;p16基因在蛋白水平表达率也高于对照组 (P <0 .0 5 )。结论　X线可诱导C6脑胶质瘤细胞发生凋亡 ,抑癌基因 p16在辐射诱导凋亡中起重要的作用。     

Multicentre CRC phase II trial of temozolomide in recurrent or progressive high-grade glioma

Purpose: Patients with progressive or recurrent supratentorial high-grade gliomas were entered into a multicentre phase II trial to evaluate the efficacy and toxicity of temozolomide. Methods: The treatment schedule was 150–200 mg/m² per day orally for 5 days repeated every 28 days. Response evaluation was by a combination of neurological status evaluation (MRC scale) and imaging. Results: Of 103 eligible patients enrolled, 11 (11%) achieved an objective response and a further 48 (47%) had stable disease. The median response duration was 4.6 months. Response rates were similar for anaplastic astrocytomas (grade III) and glioblastoma multiforme (grade IV) tumours. Predictable myelosuppression was the major toxicity. Conclusions: The observation of objective responses and tolerable side effects in this heterogeneous population of patients supports the further investigation of this agent in high-grade gliomas. Received: 24 October 1996 / Accepted 5 February 1997     

Induction of apoptosis in multi-drug resistant (MDR) human glioblastoma cells by SN-38, a metabolite of the camptothecin derivative CPT-11

 The overexpression of the multidrug resistance (mdr1) gene and its product, P-glycoprotein (P-gp), is thought to limit the successful chemotherapy of human tumors. Recent studies demonstrate that SN-38, a metabolite of the camptothecin (CPT) derivative CPT-11, has antitumor effects on several tumors, but the mechanisms responsible for its cytotoxicity remain unclear. We therefore determined whether SN-38 has cytotoxic effects on MDR human glioblastoma GB-1 cells and non-MDR human glioblastoma U87-MG cells. Furthermore, we determined what role SN-38 plays in the induction of cytotoxicity in these tumor cells. In this study, we demonstrated that SN-38 had significantly stronger antitumor effects on GB-1 and U-87MG cells than did CPT (P<0.01 and P<0.05, respectively). In addition, findings obtained using a DNA fragmentation assay, Hoechst 33258 staining, in situ end-labeling and cell cycle analysis demonstrated that SN-38 induced apoptosis in these tumors. Our results suggest that SN-38 has a stronger antitumor effect on malignant glioma cells regardless of MDR expression than does CPT, and therefore can be considered a new chemotherapeutic agent potentially effective in the treatment of human primary or recurrent malignant gliomas resistant to chemotherapy. Received: 6 October 1995/Accepted 29 June 1996     

Distribution of estramustine in the BT4C rat glioma model

 Estramustine (EaM), a carbamate ester of 17β-estradiol and nor-nitrogen mustard, is a cytotoxic compound with antitumoral effect in malignant glioma in vitro and in vivo . However, knowledge of the pharmacokinetics of EaM in experimental glioma is limited. The objective of this study was therefore to investigate further the distribution of EaM in the BT4C rat glioma model. Assessment of EaM uptake and distribution was performed by quantitative whole-body autoradiography. In addition, the uptake of EaM and its metabolites estromustine (EoM), estradiol, and estrone were analyzed by gas chromatography. EaM was taken up from the circulation and was found to be the main product in glioma tissue. Whole-body autoradiography after [¹⁴C]-EaM administration revealed a strong ¹⁴C label simultaneously in tumor and normal brain tissue at 0.5 h after drug administration. In tumor tissue, sustained high levels of ¹⁴C label were detected at 12 h after drug administration. In contrast to the tumor, radioactivity in normal brain tissue rapidly leveled off, indicating a retention of radioactivity in the tumor. The tumor/brain radioactivity ratio reached a peak of 4.5 at 12 h after drug administration. High levels of ¹⁴C label were also found in pulmonary tissue. By gas chromatography, EoM was found to be the main metabolite in plasma. However, EaM reached higher levels in tumor tissue, with the mean tumor/plasma ratio being 11.7 as compared with 2.0 for EoM. Only low plasma levels of the estrogen metabolites were detected. In conclusion, EaM is taken up in the BT4C rat glioma tissue and is retained in the tumor as compared with normal brain tissue and plasma. EaM showed a greater selectivity for tumor tissue, exhibiting a high tumor/plasma ratio as compared with EoM. The distribution pattern after administration of EaM, as evaluated by both whole-body autoradiography and gas chromatography, supports the earlier suggestion that the uptake is related to a protein with EaM-binding characteristics. Received: 12 January 1997 / Accepted: 28 August 1997     

Accumulation of class I mutant p53 and apoptosis induced by carboplatin in a human glioma cell line

Following DNA damage, wild-type p53 increases and mediates the multiple cellular responses for the repair of DNA damage or apoptosis. Inactivation of p53 by single-amino-acid substitutions contributes to the malignant phenotype and confers resistance to therapy. Among tumor-derived p53 mutants, class I mutants still retain a native-like three-dimensional structure, whereas class II mutants have unfolded DNA-binding domains. Sequencing analysis demonstrated that a human glioma cell line (U-373MG) had only a class I mutant form of p53 of His273, which targets an Arg273 that contacts DNA but retains the native structure. In this study, we investigated the metabolic alteration of the class I mutant p53 in apoptosis of U-373MG. The cell cycle progression of U-373MG cells was affected by the addition of carboplatin, while the amount of mutant p53 also increased in their nuclei. The treated cells underwent apoptosis 48h after exposure to 50 μg/ml carboplatin. Although the exact mechanism of the class I mutant p53 in the process of apoptosis has not yet been clarified, the fact that accumulation of the activated mutant p53 in the nucleus of U-373MG is concomitant with apoptosis, just as wild-type p53 does, implies that the class I mutant p53 might retain the ability to participate in apoptosis.     

Antitumor Immunity Induction by Intracellular Hyperthermia Using Magnetite Cationic Liposomes

Induction of antitumor immunity to T-9 rat glioma by intracellular hyperthermia using functional magnetic particles was investigated. Magnetite cationic liposomes (MCLs), which have a positive surface charge, were used as heating mediators for intracellular hyperthermia. Solid T-9 glioma tissues were formed subcutaneously on both femurs of female F344 rats, and MCLs were injected via a needle only into the left solid tumors (treatment side). The rats were then divided into two groups, which received no irradiation, or irradiation for 30 min given three times at 24-h intervals with an alternating magnetic field (118 kHz, 384 Oe). On the treatment side, the tumor tissue disappeared completely in many rats exposed to the magnetic field. The tumor tissue on the opposite side also disappeared completely, even though MCLs were not injected into the right solid tumors. To examine whether a long-lasting and tumor-specific immunity could be generated, the rats that had been cured by the hyperthermia treatment were rechallenged with T-9 cells 3 months later. After a period of transient growth, all tumors disappeared. Furthermore, immuno-cytochemical assay revealed that the immune response induced by the hyperthermia treatment was mediated by both CD8⁺ and CD4⁺ T cells and accompanied by a marked augmentation of tumor-selective cytotoxic T lymphocyte activity. These results suggest that our magnetic particles are potentially effective tools for hyperthermic treatment of solid tumors, because in addition to killing of the tumor cells by heat, a host immune response is induced.     

脑星形胶质瘤nm23、PCNA、GFAP、EGFR的表达及临床意义

为阐明脑星形胶质瘤生物学行为特征，给临床诊断提供参考。作者采用免疫组化ＡＢＣ方法观察４０例脑星形胶质瘤肿瘤转移抑制基因ｎｍ２３蛋白、增殖细胞核抗原（ＰＣＮＡ）、胶质纤维酸性蛋白（ＧＦＡＰ）、表皮生长因子受体（ＥＧＦＲ）表达情况。结果表明：ＧＦＡＰ、ｎｍ２３蛋白表达与胶质瘤分级呈负相关，ＰＣＮＡ、ＥＧＦＲ表达则与胶质瘤分级呈正相关；并且它们的染色强度也与分级有关。ｎｍ２３蛋白的分布类型与肿瘤的恶性程度有关。作者认为：ＰＣＮＡ、ＥＧＦＲ、ＧＦＡＰ检测可能成为该肿瘤诊断及判断其恶性程度与预后的指标；ｎｍ２３在恶性胶质瘤中的低表达与膜型分布可能成为该肿瘤浸润与转移的指标。     

基因CT120在胶质瘤中的表达及意义

目的：研究基因CT120在胶质瘤组织中的表达及其与胶质瘤组织病理学的关系。方法：应用免疫组织化学方法检测50例胶质瘤手术切除标本、3例正常脑组织中CT120蛋白的表达：应用半定量RT—PCR检测20例胶质瘤、3例正常脑组织中CT120mRNA的表达。结果：免疫组织化学检测发现正常脑组织中CT120蛋白无表达．50例胶质瘤组织中CT120蛋白表达阳性率为50．9％，不同级别胶质瘤中的表达无显著差异（χ^2=2．99，P〉0．05）；半定量RT—PCR检测正常脑组织中CT120 mRNA呈弱表达，不同病理级别胶质瘤CT120 mRNA表达无显著差异（χ^2=3．25．P〉0．05）。结论：基因120在胶质瘤有表达，但在胶质瘤发生发展中作用不明显。