Secchiero Paola, Barbarotto Elisa, Tiribelli Mario, Zerbinati Carlotta, di Iasio Maria Grazia, Gonelli Arianna, Cavazzini Francesco, Campioni Diana, Fanin Renato, Cuneo Antonio, Zauli Giorgio
Department of Morphology and Embryology, Human Anatomy Section, University of Ferrara, Via Fossato di Mortara 66, 44100 Ferrara, Italy.
Blood. 2006 May 15;107(10):4122-9. doi: 10.1182/blood-2005-11-4465. Epub 2006 Jan 26.
Deletions and/or mutations of p53 are relatively rare and late events in the natural history of B-cell chronic lymphocytic leukemia (B-CLL). However, it is unknown whether p53 signaling is functional in B-CLL and if targeted nongenotoxic activation of the p53 pathway by using nutlin-3, a small molecule inhibitor of the p53/MDM2 interaction, is sufficient to kill B-CLL cells. In vitro treatment with nutlin-3 induced a significant cytotoxicity on primary CD19(+) B-CLL cells, but not on normal CD19(+) B lymphocytes, peripheral-blood mononuclear cells, or bone marrow hematopoietic progenitors. Among 29 B-CLL samples examined, only one was resistant to nutlin-3-mediated cytotoxicity. The induction of p53 by nutlin-3 in B-CLL samples was accompanied by alterations of the mitochondrial potential and activation of the caspase-dependent apoptotic pathway. Among several genes related to the p53 pathway, nutlin-3 up-regulated the steady-state mRNA levels of PCNA, CDKN1A/p21, GDF15, TNFRSF10B/TRAIL-R2, TP53I3/PIG3, and GADD45. This profile of gene activation showed a partial overlapping with that induced by the genotoxic drug fludarabine. Moreover, nutlin-3 synergized with both fludarabine and chlorambucil in inducing B-CLL apoptosis. Our data strongly suggest that nutlin-3 should be further investigated for clinical applications in the treatment of B-CLL.
在B细胞慢性淋巴细胞白血病（B-CLL）的自然病程中，p53基因的缺失和/或突变相对少见且出现较晚。然而，目前尚不清楚p53信号通路在B-CLL中是否具有功能，以及使用p53/MDM2相互作用的小分子抑制剂nutlin-3对p53通路进行靶向非基因毒性激活是否足以杀死B-CLL细胞。用nutlin-3进行体外处理对原发性CD19(+) B-CLL细胞具有显著的细胞毒性，但对正常CD19(+) B淋巴细胞、外周血单个核细胞或骨髓造血祖细胞则无此作用。在所检测的29个B-CLL样本中，只有1个对nutlin-3介导的细胞毒性具有抗性。nutlin-3在B-CLL样本中诱导p53表达的同时，伴随着线粒体膜电位的改变和半胱天冬酶依赖性凋亡途径的激活。在与p53通路相关的几个基因中，nutlin-3上调了PCNA、CDKN1A/p21、GDF15、TNFRSF10B/TRAIL-R2、TP53I3/PIG3和GADD45的稳态mRNA水平。这种基因激活谱与基因毒性药物氟达拉滨诱导的谱有部分重叠。此外，nutlin-3与氟达拉滨和苯丁酸氮芥在诱导B-CLL细胞凋亡方面具有协同作用。我们的数据强烈表明，nutlin-3在B-CLL治疗中的临床应用值得进一步研究。
