Temozolomide as salvage treatment for recurrent intracranial ependymomas of the adult: a retrospective study

Background

Few data are available on temozolomide (TMZ) in ependymomas.We investigated the response, survival, and correlation with MGMT promoter methylation in a cohort of patients with adult intracranial ependymoma receiving TMZ as salvage therapy after failure of surgery and radiotherapy.

Patients and Methods

We retrieved clinical information from the institutional database and follow-up visits, and response to TMZ on MRI was evaluated according to the MacDonald criteria.

Results

Eighteen patients (median age, 42 y), with either WHO grade III (10) or grade II (8) ependymoma were evaluable. Tumor location at diagnosis was supratentorial in 11 patients and infratentorial in 7. Progression before TMZ was local in 11 patients, local and spinal in 6 patients, and spinal only in one patient. A median of 8 cycles of TMZ (1–24) was administered. Response to TMZ consisted of complete response (CR) in one (5%) patient, partial response (PR) in 3 (17%) patients, stable disease (SD) in 7 (39%) patients, and progressive disease (PD) in 7 (39%) patients. Maximum response occurred after 3, 10, 14, and 15 cycles, respectively, with neurological improvement in 2 patients. All 4 responding patients were chemotherapy naïve. Both anaplastic (2) and grade II (2) tumors responded. Median progression-free survival and overall survival were 9.69 months (95% CI, 3.22–30.98) and 30.55 months (95% CI, 12.85–52.17), respectively. MGMT methylation was available in 11 patients and was not correlated with response or outcome.

Conclusion

TMZ has a role in recurrent chemo-naïve adult patients with intracranial ependymoma, regardless of tumor grade and MGMT methylation. We suggest that, after failure of surgery and radiotherapy, TMZ should be considered as a possible first-line treatment for recurrent ependymoma.     

Thioridazine inhibits autophagy and sensitizes glioblastoma cells to temozolomide

Glioblastoma multiforme (GBM) has a poor prognosis with an overall survival of 14–15 months after surgery, radiation and chemotherapy using temozolomide (TMZ). A major problem is that the tumors acquire resistance to therapy. In an effort to improve the therapeutic efficacy of TMZ, we performed a genome-wide RNA interference (RNAi) synthetic lethality screen to establish a functional gene signature for TMZ sensitivity in human GBM cells. We then queried the Connectivity Map database to search for drugs that would induce corresponding changes in gene expression. By this approach we identified several potential pharmacological sensitizers to TMZ, where the most potent drug was the established antipsychotic agent Thioridazine, which significantly improved TMZ sensitivity while not demonstrating any significant toxicity alone. Mechanistically, we show that the specific chemosensitizing effect of Thioridazine is mediated by impairing autophagy, thereby preventing adaptive metabolic alterations associated with TMZ resistance. Moreover, we demonstrate that Thioridazine inhibits late-stage autophagy by impairing fusion between autophagosomes and lysosomes. Finally, Thioridazine in combination with TMZ significantly inhibits brain tumor growth in vivo, demonstrating the potential clinical benefits of compounds targeting the autophagy-lysosome pathway. Our study emphasizes the feasibility of exploiting drug repurposing for the design of novel therapeutic strategies for GBM.     

Preclinical evaluation of the first intravenous small molecule MDM2 antagonist alone and in combination with temozolomide in neuroblastoma

High-risk neuroblastoma, a predominantly TP53 wild-type (wt) tumour, is incurable in >50% patients supporting the use of MDM2 antagonists as novel therapeutics. Idasanutlin (RG7388) shows in vitro synergy with chemotherapies used to treat neuroblastoma. This is the first study to evaluate the in vivo efficacy of the intravenous idasanutlin prodrug, RO6839921 (RG7775), both alone and in combination with temozolomide in TP53 wt orthotopic neuroblastoma models. Detection of active idasanutlin using liquid chromatography-mass spectrometry and p53 pathway activation by ELISA assays and Western analysis showed peak plasma levels 1 h post-treatment with maximal p53 pathway activation 3–6 h post-treatment. RO6839921 and temozolomide, alone or in combination in mice implanted with TP53 wt SHSY5Y-Luc and NB1691-Luc cells showed that combined RO6839921 and temozolomide led to greater tumour growth inhibition and increase in survival compared to vehicle control. Overall, RO6839921 had a favourable pharmacokinetic profile consistent with intermittent dosing and was well tolerated alone and in combination. These preclinical studies support the further development of idasanutlin in combination with temozolomide in neuroblastoma in early phase clinical trials.     

BC200通过介导脑胶质瘤细胞干性的维持抑制替莫唑胺的促凋亡作用

目的：探讨血清长链非编码RNA BC200在脑胶质瘤干细胞（GSCs）中的作用及相关作用机制。方法：神经干细胞培养液培养脑胶质瘤U87 MG细胞,并提取成球生长的GSCs;采用免疫荧光法检测GSCs干细胞标志性分子CD133和Nestin;小分子RNA（siRNA）转染沉默GSCs中BC200表达;替莫唑胺（TMZ）200 μmol·L-1处理GSCs 24 h,光镜下观察TMZ对GSCs悬浮细胞球形态的影响;采用Western blot方法检测CD133、Bax、Bcl-2和cleaved caspase-3的表达变化。结果：分离提取的GSCs球状生长,细胞球表面CD133和Nestin呈阳性表达。TMZ处理GSCs 24 h,GSCs成球能力略微下降,未见细胞球状状态明显离散,Bax、cleaved cas-pase-3、Bcl-2未有明显变化（均P＞0.05）。沉默BC200后GSCs CD133表达显著下降（P＜0.05）。BC200沉默后,TMZ处理GSCs发现其成球能力明显减弱、细胞分散;cleaved caspase-3和Bax分别上调（45.36%±4.25%）和（63.23%±5.12%）,Bcl-2下调（31.22%±3.80%）,均P＜0.01。结论：BC200能够维持脑胶质瘤U87 MG细胞的干性,该效应可促进细胞对TMZ诱导凋亡的抵抗。     

甲基化抗肿瘤药物治疗中的DNA修复:治疗效果与健康结局

在甲基化抗肿瘤药物治疗中,DNA修复是决定治疗效果与不良生物效应（如突变、癌变和致畸）的一个关键机制。本文主要对甲基化抗肿瘤药物在DNA修复过程的作用进行综述。尽管这些抗肿瘤药物无选择性地靶向作用于癌细胞和正常细胞的DNA,但因其削弱了癌细胞内某些特异的DNA修复活动,从而更多地杀死癌细胞。单功能的烷化剂显示出甲基化改变特性（丙卡巴肼、达卡巴嗪、链脲佐菌素、替莫唑胺）,或者氯乙基化形成单加合物并在下一步反应中引起DNA链内交联（洛莫司汀、尼莫地平、卡莫司汀、福莫司汀）。癌细胞对抗肿瘤药物的一个主要机制是通过自杀酶O⁶-甲基鸟嘌呤-DNA甲基转移酶（MGMT）直接逆转DNA损伤,形成O⁶-甲基鸟嘌呤和O⁶-氯化鸟嘌呤。由于MGMT对恶性肿瘤治疗的结局有显著影响,它被认为是一个耐药的重要标志,特别是在高级恶性胶质瘤。MGMT也被认为是甲基化抗肿瘤药物有效性的预测标志,许多临床试验正在分析MGMT抑制对治疗效果的影响。其他涉及甲基化抗肿瘤药物耐药的DNA修复因素包括错配修复、通过同源重组和DNA双链断裂（DSB）信号启动的相关修复。碱基切除修复和alkB同源蛋白（如ABH2）也可能与烷化类药物耐药有关,该现象在高表达MGMT的细胞株异常明显。对于这些机制的进一步了解,将有助于设计更为有效的治疗方案,同时减少副作用。     

水飞蓟宾对胶质瘤细胞替莫唑胺化疗敏感性的影响

目的:研究水飞蓟宾在增加胶质瘤细胞对替莫唑胺化疗敏感性中的作用。方法:CCK-8法检测应用水飞蓟宾前后,替莫唑胺对胶质瘤细胞存活率的影响;Western Blot法检测水飞蓟宾及替莫唑胺对耐药细胞中Bcl-2、p-Akt蛋白表达水平的影响。结果:水飞蓟宾增加替莫唑胺对胶质瘤细胞的增殖抑制作用;替莫唑胺耐药的胶质瘤细胞中Bcl-2蛋白表达水平和Akt磷酸化水平显著升高;水飞蓟宾能够降低耐药细胞中Bcl-2的蛋白表达水平和Akt磷酸化水平。结论:水飞蓟宾能够增加胶质瘤细胞对替莫唑胺的化疗敏感性,并能够在一定程度上逆转胶质瘤细胞对替莫唑胺的耐药,其机制可能是通过下调PI3K/Akt信号通路和Bcl-2表达水平实现的。     

Benefits of interferon-β and temozolomide combination therapy for newly diagnosed primary glioblastoma with the unmethylated MGMT promoter: A multicenter study

BACKGROUND:

The aim of the current study was to catalog genomic and epigenomic abnormalities in newly diagnosed glioblastoma patients and determine the correlation among clinical, genetic, and epigenetic profiles and clinical outcome.

METHODS:

This study retrospectively included 68 consecutive patients who underwent surgical treatment and received standard radiotherapy with temozolomide (TMZ)‐based chemotherapy. Of a total of 68 patients, 39 patients (57.4%) received interferon (IFN)‐β in combination of TMZ.

RESULTS:

The genetic and epigenetic alterations frequently observed were EGFR amplification (51.5%), TP53 mutation (33.8%), CDKN2A loss (32.4%), TP53 loss (16.2%), methylation of the MGMT promoter (33.8%) and IDH1 mutation (5.9%). Multivariate analysis revealed that methylated MGMT promoter and the combination of TMZ and IFN‐β were independent prognostic factors associated with survival. The median survival time (MST) of the patients who received the combination of IFN‐β and TMZ was significantly greater with 19.9 months as compared to the TMZ alone group (12.7 months). Notably, in even patients whose tumors had unmethylated MGMT promoter, the MST prolonged to 17.2 months when receiving TMZ with IFN‐β, compared to 12.5 months in those receiving TMZ without IFN‐β.

CONCLUSIONS:

Taken together, addition of IFN‐β for newly diagnosed primary GBM achieved a favorable outcome, particularly in patients with unmethylated MGMT promoter. Cancer 2011. © 2010 American Cancer Society.     

Patterns of care and survival for patients with glioblastoma multiforme diagnosed during 2006

Standard treatment for glioblastoma multiforme (GBM) changed in 2005 when addition of temozolomide (TMZ) to maximal surgical resection followed by radiation therapy (RT) was shown to prolong survival in a clinical trial. In this study, we assessed treatment patterns and survival of patients with GBM in community settings in the United States. Patients with newly diagnosed GBM who were aged ≥20 years in 2006 (n = 1202) were identified as part of the National Cancer Institute 's Patterns of Care Studies. We assessed treatment patterns, and in the subset of patients who received total or partial surgical resection, we used multivariable regression analysis to assess patient, clinical, and health system factors associated with receipt of adjuvant chemotherapy and RT and survival through 2008. Approximately 65% of patients with GBM received total or partial surgical resection, and approximately 70% of these patients received adjuvant TMZ and RT. Receipt of adjuvant therapy was associated with patient age, marital status, health insurance, and tumor location. Median survival in all patients was 10 months (95% confidence interval [CI], 9-11 months). Receipt of adjuvant therapy following resection was associated with a lower risk of dying in adjusted analyses for patients who received TMZ and RT (hazard ratio [HR], 0.25; 95% CI, 0.18-0.35) and other adjuvant therapies (HR, 0.55; 95% CI, 0.37-0.81), compared with no adjuvant therapy. We observed rapid diffusion of a new standard of treatment, adjuvant and concurrent TMZ with RT, among adult patients with newly diagnosed GBM in the community setting following publication of a pivotal clinical trial.