Utilizing the Dog Genome in the Search for Novel Candidate Genes Involved in Glioma Development-Genome Wide Association Mapping followed by Targeted Massive Parallel Sequencing Identifies a Strongly Associated Locus.
Utilizing the Dog Genome in the Search for Novel Candidate Genes Involved in Glioma Development-Genome Wide Association Mapping followed by Targeted Massive Parallel Sequencing Identifies a Strongly Associated Locus.
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DOI：
10.1371/journal.pgen.1006000
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发表时间：
2016-05
期刊：
影响因子：
4.5
通讯作者：
Lindblad-Toh K
中科院分区：
文献类型：
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作者：
Truvé K;Dickinson P;Xiong A;York D;Jayashankar K;Pielberg G;Koltookian M;Murén E;Fuxelius HH;Weishaupt H;Swartling FJ;Andersson G;Hedhammar Å;Bongcam-Rudloff E;Forsberg-Nilsson K;Bannasch D;Lindblad-Toh K
神经胶质瘤是人类最常见的恶性原发性脑肿瘤，在狗中第二常见，在两种物种中发生的频率相似。狗是人类复杂疾病（包括癌症）的有价值的自发模型，可能为疾病易感性和肿瘤发生提供见解。一些短头犬品种，如拳师犬、牛头犬和波士顿梗，患神经胶质瘤的风险较高，但其他品种，包括巴哥和北京哈巴狗，风险并不高。为了确定神经胶质瘤相关的遗传易感性因素，研究人员对来自25个犬种的39例神经胶质瘤犬和141例对照犬进行了跨品种全基因组关联研究（GWAS），在犬染色体（CFA） 26上发现了一个全基因组显著位点（p = 2.8 x 10−8）。对3.4 Mb候选区域进行靶向重测序，然后对56个最符合重测序病例与对照之间关联模式的snv进行基因分型。我们确定了与胶质瘤易感性高度相关的三个候选基因：CAMKK2、P2RX7和DENR。CAMKK2在犬和人类脑肿瘤中的表达均降低，而P2RX7中的非同义变体，先前被证明具有50%的受体功能降低，也与疾病有关。因此，这些基因中的一个或多个似乎影响神经胶质瘤的易感性。神经胶质瘤是一种毁灭性的恶性脑瘤，几乎无法治愈。尽管广泛的研究来确定参与疾病发展的途径和基因，但仍然迫切需要改进治疗方法。一些犬种患神经胶质瘤的风险相当高，这使得犬类成为定位对人类神经胶质瘤发展也有潜在重要性的基因的合适模型。在这项研究中，我们定义了一个与狗的神经胶质瘤密切相关的基因组区域。我们还表明，这个基因组区域可能在患神经胶质瘤风险最高的犬种中被选择。有时，对品种特定性状的选择会导致致病突变的扩增，同时也会导致所选择的变异。我们在该区域找到了三个候选基因：CAMKK2、P2RX7和DENR。我们进行了进一步的功能研究，以评估这些基因在犬和人类胶质瘤中的潜在作用。通过比较正常组织和肿瘤组织，我们可以发现camkk2和P2RX7两个基因分别在基因表达和蛋白结构水平上受到影响。我们建议进一步研究这三个基因可能对狗和人类都有潜在的好处。
Gliomas are the most common form of malignant primary brain tumors in humans and second most common in dogs, occurring with similar frequencies in both species. Dogs are valuable spontaneous models of human complex diseases including cancers and may provide insight into disease susceptibility and oncogenesis. Several brachycephalic breeds such as Boxer, Bulldog and Boston Terrier have an elevated risk of developing glioma, but others, including Pug and Pekingese, are not at higher risk. To identify glioma-associated genetic susceptibility factors, an across-breed genome-wide association study (GWAS) was performed on 39 dog glioma cases and 141 controls from 25 dog breeds, identifying a genome-wide significant locus on canine chromosome (CFA) 26 (p = 2.8 x 10−8). Targeted re-sequencing of the 3.4 Mb candidate region was performed, followed by genotyping of the 56 SNVs that best fit the association pattern between the re-sequenced cases and controls. We identified three candidate genes that were highly associated with glioma susceptibility: CAMKK2, P2RX7 and DENR. CAMKK2 showed reduced expression in both canine and human brain tumors, and a non-synonymous variant in P2RX7, previously demonstrated to have a 50% decrease in receptor function, was also associated with disease. Thus, one or more of these genes appear to affect glioma susceptibility. Gliomas are devastating malignant brain tumors that are very rarely curable. Despite extensive research to define pathways and genes involved in the development of disease, there is still an urgent need to improve therapy. Some dog breeds have a considerable elevated risk of glioma, making the dog a suitable model for locating genes potentially of importance also for development of human glioma. In this study we defined a genomic region strongly associated with glioma in dogs. We also showed that this genomic region had likely been under selection in the dog breeds with the highest risk of developing glioma. Sometimes selection for breed specific traits results in amplification of disease causing mutations together with the variant selected for. We located three candidate genes in the identified region: CAMKK2, P2RX7 and DENR. We performed further functional studies to evaluate the potential role of these genes in both canine and human glioma. By comparing normal and tumor tissue we could show that two of the genes—CAMKK2 and P2RX7, were affected at the level of gene expression and protein structure, respectively. We propose that further investigation of all three genes could be of interest with potential benefit to both dog and human.