Bcl-2 inhibits chemotherapy-induced apoptosis in neuroblastoma.
Bcl-2 inhibits chemotherapy-induced apoptosis in neuroblastoma.
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发表时间：
1994-06
期刊：
影响因子：
11.2
通讯作者：
M. Dole;G. Núñez;Audrea K. Merchant;J. Maybaum;C. Rode;C. Bloch;V. Castle
中科院分区：
文献类型：
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作者：
M. Dole;G. Núñez;Audrea K. Merchant;J. Maybaum;C. Rode;C. Bloch;V. Castle
Bcl2是一类新的原癌基因的第一个成员，其产物可抑制细胞程序性死亡(PCD)或细胞凋亡。我们之前已经确定，在未经治疗的原发神经母细胞瘤(NBL)肿瘤中，有相当大比例的人表达Bcl2。在这些标本中，Bcl2的表达与其他预后不良的标记物相关，提示Bcl2在NBL肿瘤细胞的恶性行为中起作用。为了探讨这种可能性，将bcl2表达载体(pSFFVneo-bcl2)导入人NBL细胞系(Shep-1)。通过定量免疫沉淀法分离到多个表达不同水平的Bcl2蛋白的克隆。同时产生载体转染组。高表达Bcl2的克隆对顺铂和依托泊苷诱导的细胞毒性具有剂量依赖关系。流式细胞术分析顺铂或依托泊苷处理后的碘化丙啶染色的细胞核显示，载体转染组的DNA降解显著，而bcl2转染组的DNA降解呈剂量依赖性抑制。脉冲场凝胶电泳法分析显示，在用顺铂或依托泊苷处理的载体转染组对照细胞中，相对较大的片段DNA降解(约50千碱基)，而没有核小体间的降解。相反，在所有时间点，表达Bcl2的细胞的DNA降解明显减少。这些单基因转染实验表明，Bcl2的表达使特异性NBL细胞对化疗诱导的PCD产生耐药，并支持Bcl2通过促进肿瘤对化疗药物的耐药性而增强NBL的恶性表型的假说。
bcl-2 is the first member of a new class of protooncogenes the products of which inhibit programmed cell death (PCD) or apoptosis. We have previously determined that Bcl-2 is expressed in a significant percentage of untreated primary neuroblastoma (NBL) tumors. In these specimens Bcl-2 expression correlated with other markers of poor prognosis suggesting a role for Bcl-2 in the malignant behavior of NBL tumor cells. To investigate this possibility, a Bcl-2-negative human NBL cell line (Shep-1) was transfected with a bcl-2 expression vector (pSFFVneo-bcl-2). Multiple unique clones were isolated which showed variable levels of Bcl-2 protein by quantitative immunoprecipitation. Vector-transfected controls were generated simultaneously. Clones expressing high levels of Bcl-2 were resistant to cisplatin- and etoposide-induced cytotoxicity in a dose-dependent manner. Analysis of propidium iodide-stained nuclei by flow cytometry after cisplatin or etoposide treatment revealed marked DNA degradation in vector-transfected controls whereas bcl-2 transfectants showed a dose-dependent inhibition of DNA degradation. Analysis by pulsed-field gel electrophoresis revealed relatively large fragment DNA degradation (approximately 50 kilobases) in the absence of internucleosomal degradation in vector-transfected control cells treated with either cisplatin or etoposide. In contrast, Bcl-2-expressing cells showed significantly less DNA degradation at all time points. These single gene transfection experiments have revealed that expression of Bcl-2 renders specific NBL cells resistant to chemotherapy-induced PCD and support the hypothesis that Bcl-2 enhances the malignant phenotype of NBL by promoting tumor resistance to chemotherapy agents.