Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, Ohio State University, Columbus, OH 43210, USA.
JAMA. 2011 Jan 5;305(1):59-67. doi: 10.1001/jama.2010.1919.
Chromosomal abnormalities (namely 13q, 17p, and 11q deletions) have prognostic implications and are recurrent in chronic lymphocytic leukemia (CLL), suggesting that they are involved in a common pathogenetic pathway; however, the molecular mechanism through which chromosomal abnormalities affect the pathogenesis and outcome of CLL is unknown.
To determine whether the microRNA miR-15a/miR-16-1 cluster (located at 13q), tumor protein p53 (TP53, located at 17p), and miR-34b/miR-34c cluster (located at 11q) are linked in a molecular pathway that explains the pathogenetic and prognostic implications (indolent vs aggressive form) of recurrent 13q, 17p, and 11q deletions in CLL.
DESIGN, SETTING, AND PATIENTS: CLL Research Consortium institutions provided blood samples from untreated patients (n = 206) diagnosed with B-cell CLL between January 2000 and April 2008. All samples were evaluated for the occurrence of cytogenetic abnormalities as well as the expression levels of the miR-15a/miR-16-1 cluster, miR-34b/miR-34c cluster, TP53, and zeta-chain (TCR)-associated protein kinase 70 kDa (ZAP70), a surrogate prognostic marker of CLL. The functional relationship between these genes was studied using in vitro gain- and loss-of-function experiments in cell lines and primary samples and was validated in a separate cohort of primary CLL samples.
Cytogenetic abnormalities; expression levels of the miR-15a/miR-16-1 cluster, miR-34 family, TP53 gene, downstream effectors cyclin-dependent kinase inhibitor 1A (p21, Cip1) (CDKN1A) and B-cell CLL/lymphoma 2 binding component 3 (BBC3), and ZAP70 gene; genetic interactions detected by chromatin immunoprecipitation.
In CLLs with 13q deletions the miR-15a/miR-16-1 cluster directly targeted TP53 (mean luciferase activity for miR-15a vs scrambled control, 0.68 relative light units (RLU) [95% confidence interval {CI}, 0.63-0.73]; P = .02; mean for miR-16 vs scrambled control, 0.62 RLU [95% CI, 0.59-0.65]; P = .02) and its downstream effectors. In leukemic cell lines and primary CLL cells, TP53 stimulated the transcription of miR-15/miR-16-1 as well as miR-34b/miR-34c clusters, and the miR-34b/miR-34c cluster directly targeted the ZAP70 kinase (mean luciferase activity for miR-34a vs scrambled control, 0.33 RLU [95% CI, 0.30-0.36]; P = .02; mean for miR-34b vs scrambled control, 0.31 RLU [95% CI, 0.30-0.32]; P = .01; and mean for miR-34c vs scrambled control, 0.35 RLU [95% CI, 0.33-0.37]; P = .02).
A microRNA/TP53 feedback circuitry is associated with CLL pathogenesis and outcome. This mechanism provides a novel pathogenetic model for the association of 13q deletions with the indolent form of CLL that involves microRNAs, TP53, and ZAP70.
染色体异常（即 13q、17p 和 11q 缺失）具有预后意义，并且在慢性淋巴细胞白血病（CLL）中反复出现，这表明它们涉及共同的发病途径；然而，染色体异常影响 CLL 发病机制和结果的分子机制尚不清楚。
确定 microRNA miR-15a/miR-16-1 簇（位于 13q）、肿瘤蛋白 p53（TP53，位于 17p）和 miR-34b/miR-34c 簇（位于 11q）是否在分子途径中相关联，该途径解释了 CLL 中反复出现的 13q、17p 和 11q 缺失的发病机制和预后意义（惰性与侵袭性形式）。
设计、地点和患者：CLL 研究联盟机构提供了 206 名未经治疗的患者（2000 年 1 月至 2008 年 4 月期间诊断为 B 细胞 CLL）的血液样本。所有样本均评估了细胞遗传学异常以及 miR-15a/miR-16-1 簇、miR-34b/miR-34c 簇、TP53 和 ζ-链（TCR）相关蛋白激酶 70 kDa（ZAP70）的表达水平，ZAP70 是 CLL 的替代预后标志物。使用细胞系和原代样本中的体外增益和失能实验研究了这些基因之间的功能关系，并在另一个 CLL 原代样本队列中进行了验证。
细胞遗传学异常；miR-15a/miR-16-1 簇、miR-34 家族、TP53 基因、下游效应子细胞周期蛋白依赖性激酶抑制剂 1A（p21、Cip1）（CDKN1A）和 B 细胞 CLL/淋巴瘤 2 结合成分 3（BBC3）以及 ZAP70 基因的表达水平；通过染色质免疫沉淀检测到的遗传相互作用。
在具有 13q 缺失的 CLL 中，miR-15a/miR-16-1 簇直接靶向 TP53（miR-15a 与对照的平均荧光素酶活性，0.68 相对光单位（RLU）[95%置信区间（CI），0.63-0.73]；P =.02；miR-16 与对照的平均荧光素酶活性，0.62 RLU [95% CI，0.59-0.65]；P =.02）及其下游效应子。在白血病细胞系和原代 CLL 细胞中，TP53 刺激 miR-15/miR-16-1 以及 miR-34b/miR-34c 簇的转录，miR-34b/miR-34c 簇直接靶向 ZAP70 激酶（miR-34a 与对照的平均荧光素酶活性，0.33 RLU [95% CI，0.30-0.36]；P =.02；miR-34b 与对照的平均荧光素酶活性，0.31 RLU [95% CI，0.30-0.32]；P =.01；miR-34c 与对照的平均荧光素酶活性，0.35 RLU [95% CI，0.33-0.37]；P =.02）。
microRNA/TP53 反馈电路与 CLL 的发病机制和结果相关。该机制为涉及 microRNAs、TP53 和 ZAP70 的 13q 缺失与 CLL 惰性形式相关联的发病机制提供了一个新的模型。
