MGMT表达与替莫唑胺治疗多形性胶质母细胞瘤耐药的关系

多形性胶质母细胞瘤是中枢神经系统最常见的恶性肿瘤,而且在胶质瘤中恶性程度最高.替莫唑胺为治疗多形性胶质母细胞瘤的新型烷化剂类口服化疗药物,研究表明替莫唑胺的耐药机制与O6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)的表达相关.了解多形性胶质母细胞瘤应用替莫唑胺治疗的耐药性与MGMT表达的相关性对临床治疗很有帮助.     

109例脑恶性胶质瘤患者术后联合放射治疗的临床疗效分析

目的观察脑胶质瘤患者术后进一步联合三维适形放疗等综合治疗方式的疗效和安全性。方法回顾性分析我院109例术后联合放射治疗等多种治疗方式的脑恶性胶质细胞瘤患者的病历资料,对近期疗效和不良反应进行评价,随访时间12～36个月,中位随访时间13个月,计算患者1～3年生存率。结果 109例脑恶性胶质细胞瘤患者均按计划完成治疗,1个月后返院MRI复查结果提示：完全缓解（CR）75例,部分缓解（PR）14例,稳定（SD）13例,疾病进展（PD）7例,客观有效率（RR）为81.6%,疾病探制率（DCR）为93.6%。中位无疾病进展时间（TTP）为14个月,放化疗过程主要毒性表现在脑组织水肿、消化道和骨髓造血功能的抑制等方面。34例患者经MRI检查证实发生放射性脑水肿,发生几率为31.2%。结论精确的肿瘤切除术后及时的放疗对控制术后残留病灶,完全阻断肿瘤生长根源有重要意义,如能同时接受正规的化疗以及特异性的靶向药物治疗,可收到较好的效果,是目前首选的综合治疗方式。     

重组腺病毒p53 上调凋亡调控因子通过凋亡通路增强胶质瘤细胞对替莫唑胺敏感性的体外研究

目的 探讨转染p53 上调凋亡调控因子(PUMA)的人脑胶质瘤细胞对替莫唑胺敏感性增强的作用机制.方法 将人脑胶质瘤细胞U87MG 分为正常对照组、空载体组和实验组进行培养,分别将感染复数(MOI) ＝50 的空载体腺病毒(Ad-△ BH3)和携带PUMA 的重组腺病毒(Ad-PUMA)转染U87MG 细胞,转染后用MTT 比色法测定各组细胞的存活率并计算替莫唑胺(TMZ)IC50,流式细胞仪检测细胞周期的变化,应用TUNEL 法检测细胞的凋亡情况.Western blot 检测凋亡相关蛋白p53、Bax 的表达.结果 外源性PUMA 基因在Ad-PUMA 转染U87MG 48 h 后,随着时间延长,PUMA 表达使U87MG 细胞的增殖能力降低并诱导凋亡,转染24 h、48 h、72 h 的生长抑制率分别为17.3%、35.6%、43.3%,凋亡率分别为20.3%、31.4%、45.4%.正常对照组、Ad-PUMA、Ad-△BH3 组细胞的TMZ IC50分别为(15.0 ±1.9)μmol/L、(2.3 ±0.1)μmol/L 和(14.4 ±1.6)μmol/L.PUMA 表达的U87MG 细胞DNA 合成受到抑制,周期阻滞在G2 期;Western blot 检测显示p53 表达在各组中差异无统计学意义(P ＞0.05)、PUMA 和Bax 在实验组中表达较对照组强,差异有统计学意义(P ＜0.01).结论 Ad-PU-MA 转染可有效增强人脑胶质瘤细胞U87MG 对TMZ 的敏感性,抑制人脑胶质瘤细胞U87MG 的增殖,通过诱导细胞G2 期阻滞促进其凋亡,促凋亡机制不依赖于p53.     

双氢青蒿素诱导胶质瘤细胞自噬作用的研究

目的 研究双氢青蒿素(DHA)抑制胶质瘤生长作用、机制及联合替莫唑胺(TMZ)的协同抗肿瘤作用.方法 选用胶质瘤细胞株10个,MTT法检测DHA持续作用72 h后细胞株半数抑制浓度(IC50);0.5 μg/ml浓度DHA联合梯度浓度TMZ作用于SKMG-4细胞株,MTT法检测IC50;MDC法荧光分析DHA作用后自噬泡形成;梯度浓度DHA作用SKMG-4,Western Blot法检测caspase-3、Beclin -1、LC3-B蛋白表达.结果 DHA抑制胶质瘤细胞生长IC50为(1.17±0.078)μg/ml-(23.568±0.796)μg/ml;在SKMG-4细胞株中,DHA实验组与空白对照相比,可见明显的自噬泡染色;Beclin-1及LC3-B表达随DHA浓度增加而增加,而cagpase-3表达无明显变化;DHA联合TMZ抑制SKMG-4生长,IC50值明显下降(P＜0.01).结论 DHA具有抗胶质瘤活性,诱导胶质瘤细胞自噬;DHA联合作用可提高TMZ的抗胶质瘤SKMG-4活性,机制可能为增强了TMZ自噬效能.

Abstract：

Objective To investigate the anti - glioma efficacy of dihydroartemisinin ( DHA) and combined with temozolomide (TMZ) on human glioma cell line in vitro. Methods The growth inhibition of DHA on 10 glioma cell lines induced by DHA treatment for 72 h was analyzed by MTT method. TMZ combined with 0. 5 μg/ml DHA, and the IC50 value was measured in SKMG - 4 cells. The autofluorescent drug monodansylcadaverine (MDC) was used to mark autophagicvacuoles. The autophagy related protein LC3 - B and Beclin - 1, and the apoptosis protein caspase - 3 were analyzed by western blot ( WB). Results The IC50 of DHA was different in ten glioma cell lines [from (1. 17 ±0. 078) μg/ml to (23. 568 ±0. 796) μg/ml]. In SKMG -4 cells, the autophagicvacuoles were detected in the DHA group, the IC50 of TMZ had significant difference with 0. 5 μg/ml DHA contrast to the control group ( P ＜ 0. 01), and the levels of LC3 - B and Beclin -1 protein were increased gradually with the increase of DHA concentration, and caspase - 3 protein has no difference. Conclusion DHA can inhibit proliferation of glioma cell lines and increase the efficacy of TMZ, and the autophagy may be the mechanism.     

Targeted therapy in advanced well-differentiated neuroendocrine tumors

Treatments for advanced neuroendocrine tumors were, until recently, rather limited. Salvage surgery and liver-directed therapy both have relatively limited impact, and systemic cytotoxic chemotherapy has minimal efficacy. In the absence of other effective treatments, somatostatin analogs have been used for years to control disease and neuroendocrine symptoms, without cytotoxic intent. Advances in targeted therapy for neuroendocrine tumors have opened several potentially new treatment paradigms in the management of these otherwise relatively drug-resistant neoplasms. Promising results have emerged from studies evaluating radiolabeled somatostatin analogs and inhibitors of the vascular endothelial growth factor and mammalian target of rapamycin pathways. This article reviews several of the more encouraging developments in this field.     

替莫唑胺治疗胶质母细胞瘤的长期疗效评价

目的 以卡莫司汀(BCNU)为对照,观察替莫唑胺(TMZ)对胶质母细胞瘤化疗的疗效,并探讨O6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)的表达对胶质母细胞瘤预后的影响. 方法 天津市环湖医院神经外科自2004年1月至2009年1月使用化疗药物治疗胶质母细胞瘤患者283例,其中应用TMZ 97例(TMZ组),BCNU 186例(BCNU组),免疫组织化学染色检测手术切除的肿瘤组织中MGMT的表达,对患者进行随访并比较2组患者的生存率、客观有效率和并发症的发生. 结果 TMZ组患者累积生存率高于BCNU组,差异有统计学意义(x2=27.944,P=0.000);TMZ组、BCNU组患者的客观有效率分别是75.26％(73/97)和45.16％(84/186),差异有统计学意义(x2=24.753,P=0.000);与BCNU组比较,TMZ组白细胞减少症的发生率较低,差异有统计学意义(x2=15.681,P=0.000). 结论 TMZ治疗胶质母细胞瘤疗效较BCNU显著,副作用小,耐受性好,是一种理想的胶质母细胞瘤术后化疗药物.     

Toxicity and efficacy of protracted low dose temozolomide for the treatment of low grade gliomas

Protracted low dose temozolomide (75 mg/m²/day on days 1–21 of 28 days) offers potential advantages over standard temozolomide schedules (200 mg/m²/day on days 1–5 of 28 days) including greater cumulative drug exposure and depletion of O⁶-alkylguanine DNA alkyltransferase levels, theoretically overcoming intrinsic chemoresistance. We retrospectively review our experience in 25 patients with pathologically proven low grade gliomas (LGG) treated with protracted low dose temozolomide to primarily quantify its toxicity and secondarily to assess efficacy. None had previously received radiation. Tumor response was graded based on changes in tumor size, steroid requirements, and clinical exam. About 243 cycles of protracted low dose temozolomide were administered. Three patients (12%) were changed to standard temozolomide dosing due to side effects, including intractable nausea (n = 2) and multiple cytopenias (n = 1). The most frequent toxicities were fatigue (76%), lymphopenia (72% [48% high grade]), constipation (56%), and nausea (52%). High grade toxicities (other than lymphopenia) included secondary malignancy, pruritis, hyponatremia, neutropenia, leukopenia, and cognitive decline (n = 1 for each). Tumor response rate was 52% and and disease control rate was 84%. Six month PFS was 92% and 12 month PFS was 72%. Response rates and PFS were independent of pathological subtype, deletion status, and indication for chemotherapy. Protracted low dose temozolomide has a distinct spectrum of toxicities compared to standard dosing but is well tolerated in most patients and may provide improved response rates compared to standard dosing. The results of larger randomized trials are needed to assess its potential advantages over other management schemes.     

The importance of early postoperative radiation in spinal myxopapillary ependymomas

Primary brain high-grade gliomas, excluding glioblastoma are rare and heterogeneous tumors, showing different characteristic mutations and a better prognosis than glioblastomas. The addition of chemotherapy to the radiotherapy in the newly diagnosed disease has not been established yet. We treated 9 patients with newly diagnosed tumors with temozolomide at 75 mg/m2 for 7 days a week during standard radiotherapy, followed by six cycles at 200 mg/m2 on days 1–5 every 28 days. Fluorescence in situ hybridization for the 1 p/19 q loss was performed in seven out of the 9 patients. With a median follow-up of 15 months (range, 8–50), eight patients are alive and one died from disease progression. Four patients had disease progression at 7, 15, 14 and 13 months from the diagnosis. The 1 p/19 q loss was found in 5 patients; three have no evidence of disease, one had partial disease remission and one disease progression. Toxicities included one discitis requiring treatment withdrawal and specific antibiotic therapy, and one transient grade 3 psoriasiform reaction. Based on this small series of patients, the addition of temozolomide to radiotherapy may be recommended.     

Pharmacokinetic study of temozolomide on a daily-for-5-days schedule in Japanese patients with relapsed malignant gliomas: first study in Asians

Background Temozolomide (TMZ) is widely used in Europe and the United States. For the safe use of TMZ in the Japanese, as representative of Asians, the pharmacokinetics of TMZ was investigated in Japanese patients and compared to that in Caucasians. Methods The pharmacokinetics and safety of TMZ following oral administration of 150 and 200 mg/m² per day for the first 5 days of a 28-day treatment cycle were investigated in six Japanese patients with relapsed gliomas. Results The time-to-maximum plasma concentration (tmax) of TMZ was about 1 h and the elimination half-life of terminal excretion phase (t_1/2λz) was about 2 h. A dose-dependent increase was observed in maximum plasma concentration (Cmax) and AUC, while values for t_1/2λz, apparent total body clearance (CL/F), and apparent distribution volume (Vz/F) were independent of dose. After administration for 5 days, changes in pharmacokinetics and accumulation were not observed. The plasma 5-(3-methyl)1-triazen-1-yl-imidazole-4-carboxamide (MTIC) concentration changed in parallel with the TMZ plasma concentration, and the Cmax and AUC of MTIC were about 2% of those of TMZ. The pharmacokinetic parameters of TMZ and MTIC in Japanese patients in this study were comparable to those previously determined in Caucasian subjects. Adverse events occurred in all patients, but toxicities were mostly mild or moderate, and continuation of administration was possible by adjusting the dose and by delaying the start of the next treatment cycle. Conclusion The pharmacokinetic and safety profile of TMZ in Japanese patients was comparable to that in Caucasians. The treatment regimen used in Europe and the United States will be suitable for Asian patients, including Japanese.     

A phase II study of extended dose temozolomide and thalidomide in previously treated patients with metastatic melanoma

Purpose To assess the efficacy and tolerability of extended dose temozolomide and continuous thalidomide in patients with advanced metastatic cutaneous melanoma.Patients and methods Eligibility criteria included adults with histologic diagnosis of metastatic melanoma with adequate organ function and performance status. Temozolomide (75 mg/m²/day) was administered for 6 weeks followed by a 2-week rest. Thalidomide (200 mg/day) was given for the first 2 weeks and increased by 100 mg/day at weekly intervals up to a maximum of 400 mg/day, if no toxicity. For patients older than 70 years, thalidomide was started at 100 mg/day and the dose was increased by 50 mg/day up to a maximum of 250 mg/day.Results Twenty-six extensively pretreated subjects, with poor prognostic factors, were entered into this study and included in all analyses. According to the RECIST criteria, one (4%) subject achieved a complete response (CR), two (8%) partial response (PR), and five (19%) stable disease (SD), for a response rate (CR + PR) of 12% [95% confidence interval (CI), 0–24.7%] and a clinical benefit (CR + PR + SD) of 31%. Median time to progression was 1.8 months (95% CI, 1.2–2.4 months) and median survival was 5.2 months (95% CI, 4.1–6.2 months).Conclusions The combination of temozolomide and thalidomide is well tolerated in patients with very advanced heavily pretreated metastatic melanoma. It has modest activity in this population with grave prognosis.