Restoration of p53 Pathway by Nutlin-3 Induces Cell Cycle Arrest and Apoptosis in Human Rhabdomyosarcoma Cells
Restoration of p53 Pathway by Nutlin-3 Induces Cell Cycle Arrest and Apoptosis in Human Rhabdomyosarcoma Cells
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DOI：
10.1158/1078-0432.ccr-08-2955
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发表时间：
2009-06-15
影响因子：
11.5
通讯作者：
Hosoi, Hajime
中科院分区：
文献类型：
--
作者：
Miyachi, Mitsuru;Kakazu, Naoki;Hosoi, Hajime
目的：横纹肌肉瘤(RMS)中70%至80%的肿瘤保留野生型P53。肿瘤抑制基因P53在诱导细胞周期停滞或对各种应激反应中的细胞凋亡中起着核心作用。MDM2通过泛素依赖的降解来调节P53蛋白水平。在这项研究中，我们评估了新近开发的MDM2小分子拮抗剂Nutlin-3对培养的人RMS细胞系P53依赖的细胞周期停滞和细胞凋亡的影响。实验设计：用Nutlin-3处理5株不同P53状态和MDM2表达水平的RMS细胞。结果：野生型p53细胞经Nutlin-3处理后，P53基因表达明显增强，细胞存活率、细胞周期、细胞凋亡率及与长春新碱和放线菌素D合用的抗肿瘤活性明显增强。P53的激活导致细胞周期停滞，同时p21表达增加。此外，这些细胞系经历了P53依赖性的凋亡，伴随着促凋亡基因的上调和caspase-3的激活。无论MDM2是否过表达，Nutlin-3在半数最大抑制浓度和细胞凋亡方面的作用几乎相同。长春新碱或放线菌素D与Nutlin-3联合应用可增强野生型p53 RMS细胞的抗肿瘤活性。结论：Nutlin-3能有效恢复MDM2正常表达和MDM2高表达野生型P53细胞的P53功能。P53修复治疗是野生型P53难治性RMS的潜在治疗策略。
Purpose: Seventy to eighty percent of rhabdomyosarcoma (RMS) tumors retain wild-type p53. The tumor suppressor p53 plays a central role in inducing cell cycle arrest or apoptosis in response to various stresses. p53 protein levels are regulated by MDM2 through ubiquitin-dependent degradation. In this study, we evaluated whether nutlin-3, a recently developed small-molecule antagonist of MDM2, has an effect on p53-dependent cell cycle arrest and apoptosis in cultured human RMS cell lines.Experimental Design: Five RMS cell lines with different p53 statuses and MDM2 expression levels were treated with nutlin-3. Gene expression patterns, cell viability, cell cycle, and apoptosis after nutlin-3 treatment, and antitumor activity of combination treatment with vincristine or actinomycin D were assessed.Results: Significant p53 activation was observed in wild-type p53 cell lines after nutlin-3 treatment. p53 activation led to cell cycle arrest in parallel with increased p21 expression. Furthermore, these cell lines underwent p53-dependent apoptosis, concomitant with elevation of proapoptotic genes and activation of caspase-3. The effect of nutlin-3 was almost the same in terms of half maximal inhibitory concentration and apoptosis whether or not MDM2 was overexpressed. Nutlin-3 did not induce either cell cycle arrest or apoptosis in p53 mutant cell lines, A combination of vincristine or actinomycin D with nutlin-3 enhanced the antitumor activity in RMS cell lines with wild-type p53.Conclusions: Nutlin-3 effectively restored p53 function in both normal MDM2 expression and MDM2 overexpression RMS cell lines with wild-type p53. p53 restoration therapy is a potential therapeutic strategy for refractory RMS with wild-type p53.