杂合性 ATM 缺失的存在可能在慢性淋巴细胞白血病细胞对氟达拉滨的初始反应中并非关键因素。

Presence of heterozygous ATM deletion may not be critical in the primary response of chronic lymphocytic leukemia cells to fludarabine.

作者信息

Cejkova Sona, Rocnova Ludmila, Potesil David, Smardova Jana, Novakova Vera, Chumchalova Jitka, Zezulkova Dita, Borsky Marek, Doubek Michael, Brychtova Yvona, Pospisilova Sarka, Klabusay Martin, Mayer Jiri, Trbusek Martin

机构信息

Department of Internal Medicine - Hematooncology, University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.

出版信息

Eur J Haematol. 2009 Feb;82(2):133-42. doi: 10.1111/j.1600-0609.2008.01177.x. Epub 2008 Nov 6.

DOI:10.1111/j.1600-0609.2008.01177.x

PMID:19018867

Abstract

OBJECTIVES

Abnormalities of the TP53 or ATM, cooperating tumor-suppressor genes, significantly worsen the treatment options for chronic lymphocytic leukemia (CLL) patients. Although the aberrations seem to be mutually exclusive in this leukemia, inactivation of the former gene leads to worse prognosis. We tested the in vitro sensitivity of the CLL samples with heterozygous ATM deletion to fludarabine and combination of fludarabine and rituximab; the responses were compared with the TP53-abnormal and wild-type (wt) cells to delimitate relative significance of ATM deletion.

METHODS

In vitro analysis was performed on fifty-nine characterized CLL samples using viability assay WST-1. Western blot and real-time RT-PCR were used to monitor the activation of the ATM/p53 pathway.

RESULTS AND CONCLUSIONS

At the clinically relevant concentration of fludarabine, TP53-abnormal samples exhibited markedly higher resistance to fludarabine than the remaining CLL samples (P = 0.012); cohort with ATM deletion was not more resistant than wt cells. A similar induction of the p53 protein and its downstream target genes PUMA and BAX in ATM-deleted and wt cells confirmed that the former subgroup has preserved a critical pro-apoptotic response. Proportions of the samples, which had been sensitized to fludarabine by rituximab pretreatment, were insignificantly lower (P = 0.22) in the TP53-abnormal and ATM-deleted subgroups compared to the wt cases (30%; 29%; 50%, respectively). The presence of ATM (11q22-23) deletion in the CLL cells should not be considered an indication of resistance to fludarabine or its combination with rituximab.

摘要

目的

TP53或ATM这两个协同作用的抑癌基因发生异常，会显著恶化慢性淋巴细胞白血病（CLL）患者的治疗选择。尽管在这种白血病中这些畸变似乎相互排斥，但前一个基因的失活会导致更差的预后。我们检测了杂合性ATM缺失的CLL样本对氟达拉滨以及氟达拉滨与利妥昔单抗联合用药的体外敏感性；将这些反应与TP53异常和野生型（wt）细胞进行比较，以界定ATM缺失的相对重要性。

方法

使用WST - 1活力测定法对59个已表征的CLL样本进行体外分析。采用蛋白质免疫印迹法和实时逆转录聚合酶链反应监测ATM/p53信号通路的激活情况。

结果与结论

在临床相关浓度的氟达拉滨作用下，TP53异常的样本对氟达拉滨的耐药性明显高于其余CLL样本（P = 0.012）；ATM缺失的样本组与wt细胞相比并无更高的耐药性。在ATM缺失和wt细胞中p53蛋白及其下游靶基因PUMA和BAX的类似诱导情况证实，前一个亚组保留了关键的促凋亡反应。与wt病例相比，TP53异常和ATM缺失亚组中经利妥昔单抗预处理后对氟达拉滨敏感的样本比例略低（分别为30%、29%、50%，P = 0.22）。CLL细胞中ATM（11q22 - 23）缺失的存在不应被视为对氟达拉滨或其与利妥昔单抗联合用药耐药的指标。