z-Leucinyl-Leucinyl-Norleucinal Induces Apoptosis of Human Glioblastoma Tumor-initiating Cells by Proteasome Inhibition and Mitotic Arrest Response
z-Leucinyl-Leucinyl-Norleucinal Induces Apoptosis of Human Glioblastoma Tumor-initiating Cells by Proteasome Inhibition and Mitotic Arrest Response
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DOI：
10.1158/1541-7786.mcr-09-0225
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发表时间：
2009-11-01
影响因子：
5.2
通讯作者：
Castagnola, Patrizio
中科院分区：
文献类型：
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作者：
Monticone, Massimiliano;Biollo, Emanuela;Castagnola, Patrizio
伽马分泌酶抑制剂已被认为是能够通过靶向Noch途径杀死癌细胞的药物。在这里，我们研究了两种这样的抑制剂，苯氧甲酰-亮氨酸-亮氨酸-NLE-CHO(LLNLE)和N-[N-(3，5-difluorophenacetyl)-L-alanyl]-S-phenylglycine叔丁酯(DAPT)，以评估它们在体外是否有效地杀伤人胶质母细胞瘤肿瘤起始细胞(GBMTIC)。我们发现只有LLNle才能在微摩尔范围内通过细胞凋亡诱导GBM TICS的死亡。为了确定LLNle处理后GBM TICS中被激活的细胞过程，我们分析了LLNle、DAPT和DMSO(Vehicle)处理后细胞内Noch结构域的数量和基因表达谱。我们发现，LLNle除了抑制Noch胞内结构域的产生外，还通过抑制DNA合成和有丝分裂进程所需的基因和激活作为有丝分裂抑制因子的基因，在这些细胞中诱导蛋白酶体抑制、蛋白水解性应激和有丝分裂停止。DNA含量流式细胞术清楚地显示，LLNle处理的细胞停滞在细胞周期的G(2)-M期。我们还发现，DAPT和另一种选择性Notch抑制剂L-685,458不能杀死GBM抽动，而纯蛋白酶体抑制剂lactacystin有效，但幅度比LLNle小得多。这些数据表明，LLNle通过抑制蛋白酶体的活性而杀死GBM TIC细胞。我们认为，LLNle能够靶向GBM TIC存活的两条相关途径，可能具有潜在的治疗价值，值得在动物模型中进一步研究。(摩尔癌症研究2009；7(11)：1822-34)
gamma-secretase inhibitors have been proposed as drugs able to kill cancer cells by targeting the NOTCH pathway. Here, we investigated two of such inhibitors, the Benzyloxicarbonyl-Leu-Leu-Nle-CHO (LLNle) and the N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), to assess whether they were effective in killing human glioblastoma tumor-initiating cells (GBM TIC) in vitro. We found that only LLNle was able at the micromolar range to induce the death of GBM TICs by apoptosis. To determine the cellular processes that were activated in GBM TICs by treatment with LLNle, we analyzed the amount of the NOTCH intracellular domain and the gene expression profiles following treatment with LLNle, DAPT, and DMSO (vehicle). We found that LLNle, beside inhibiting the generation of the NOTCH intracellular domain, also induces proteasome inhibition, proteolytic stress, and mitotic arrest in these cells by repressing genes required for DNA synthesis and mitotic progression and by activating genes acting as mitotic inhibitors. DNA content flow cytometry clearly showed that cells treated with LLNle undergo arrest in the G(2)-M phases of the cell cycle. We also found that DAPT and L-685,458, another selective Notch inhibitor, were unable to kill GBM TICs, whereas lactacystin, a pure proteasome inhibitor, was effective although at a much less extent than LLNle. These data show that LLNle kills GBM TIC cells by inhibiting the proteasome activity. We suggest that LLNle, being able to target two relevant pathways for GBM TIC survival, may have a potential therapeutic value that deserves further investigation in animal models. (Mol Cancer Res 2009;7(11):1822-34)