Reduced BRCA1 transcript levels in freshly isolated blood leukocytes from BRCA1 mutation carriers is mutation specific.
Reduced BRCA1 transcript levels in freshly isolated blood leukocytes from BRCA1 mutation carriers is mutation specific.
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DOI：
10.1186/s13058-016-0739-8
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发表时间：
2016-08-17
期刊：
影响因子：
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通讯作者：
Kotsopoulos J
中科院分区：
文献类型：
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作者：
Chehade R;Pettapiece-Phillips R;Salmena L;Kotlyar M;Jurisica I;Narod SA;Akbari MR;Kotsopoulos J
BRCA1 突变携带者一生中面临着患乳腺癌和卵巢癌的高风险。单倍体不足被认为会减少可用的 BRCA1 转录物和蛋白质库，从而损害 BRCA1 功能，从而使这些女性更容易患癌症。尚未评估无癌 BRCA1 突变携带者外周血白细胞中的信使 (m)RNA 转录水平是否较低。本研究的主要目的是确定具有 BRCA1 突变的健康女性中 BRCA1 突变状态与 BRCA1 mRNA 白细胞表达水平之间的关联。 RNA 是从 58 名无癌症女性参与者（22 名 BRCA1 突变携带者和 36 名非携带者）新鲜分离的外周血白细胞中提取的。使用 Nanostring Technologies nCounter 分析系统的人类癌症参考基因组对 236 个癌症相关基因（包括 BRCA1）的表达水平进行了定量。多变量模型表明，携带 BRCA1 突变是 BRCA1 mRNA 水平最重要的预测因子。与非携带者相比，BRCA1 突变携带者的 BRCA1 mRNA 水平显着降低（146.7 计数 vs. 175.1 计数；P = 0.002）。外显子 11 内具有 BRCA1 突变的样本的 BRCA1 mRNA 水平低于 BRCA1 基因 5' 和 3' 区域内发生突变的样本（分别为 122.1 计数 vs. 138.9 和 168.6 计数；P = 0.003）。对新鲜分离的血液白细胞的基因表达谱进行无监督的层次聚类显示，与 BRCA1 野生型样本相比，BRCA1 突变携带者与其他 BRCA1 突变携带者的聚类更加紧密。此外，一组17个基因（包括BRCA1）先前被证明与致癌作用有关，但在BRCA1突变携带者和非携带者之间存在差异表达。总体而言，这些发现支持 BRCA1 单倍体不足的概念，其中特定突变导致 BRCA1 在转录水平上发生剂量依赖性改变。这项研究首次表明，从健康、未受影响的 BRCA1 突变携带者中新鲜分离的血液白细胞中，BRCA1 mRNA 表达下降。本文的在线版本 (doi:10.1186/s13058-016-0739-8) 包含补充材料，可供授权用户使用。
BRCA1 mutation carriers face a high lifetime risk of developing both breast and ovarian cancer. Haploinsufficiency is thought to predispose these women to cancer by reducing the pool of available BRCA1 transcript and protein, thereby compromising BRCA1 function. Whether or not cancer-free BRCA1 mutation carriers have lower messenger (m)RNA transcript levels in peripheral blood leukocytes has not been evaluated. The primary aim of this study was to characterize an association between BRCA1 mutation status and BRCA1 mRNA leukocyte expression levels among healthy women with a BRCA1 mutation. RNA was extracted from freshly isolated peripheral blood leukocytes of 58 cancer-free, female participants (22 BRCA1 mutation carriers and 36 non-carriers). The expression levels of 236 cancer-associated genes, including BRCA1, were quantified using the Human Cancer Reference gene panel from the Nanostring Technologies nCounter Analysis System. Multivariate modeling demonstrated that carrying a BRCA1 mutation was the most significant predictor of BRCA1 mRNA levels. BRCA1 mRNA levels were significantly lower in BRCA1 mutation carriers compared to non-carriers (146.7 counts vs. 175.1 counts; P = 0.002). Samples with BRCA1 mutations within exon 11 had lower BRCA1 mRNA levels than samples with mutations within the 5′ and 3′ regions of the BRCA1 gene (122.1 counts vs. 138.9 and 168.6 counts, respectively; P = 0.003). Unsupervised hierarchical clustering of gene expression profiles from freshly isolated blood leukocytes revealed that BRCA1 mutation carriers cluster more closely with other BRCA1 mutation carriers than with BRCA1 wild-type samples. Moreover, a set of 17 genes (including BRCA1) previously shown to be involved in carcinogenesis, were differentially expressed between BRCA1 mutation carriers and non-carriers. Overall, these findings support the concept of BRCA1 haploinsufficiency wherein a specific mutation results in dosage-dependent alteration of BRCA1 at the transcriptional level. This study is the first to show a decrease in BRCA1 mRNA expression in freshly isolated blood leukocytes from healthy, unaffected BRCA1 mutation carriers. The online version of this article (doi:10.1186/s13058-016-0739-8) contains supplementary material, which is available to authorized users.