Li Xinru, Pu Jun, Liu Jiaxin, Chen Yijun, Li Yu, Hou Peng, Shi Bingyin, Yang Qi
Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, PR China.
Department of Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, PR China.
Pathol Res Pract. 2018 Jul;214(7):940-948. doi: 10.1016/j.prp.2018.05.023. Epub 2018 May 22.
The gene of death associated protein kinase 1 (DAPK1) has been reported to be methylated in various cancers including gliomas. However, its prognostic value for gliomas is still controversy, and the methylation at specific CpG sites of DAPK1 has not been investigated. The aim of this study was to prognostically evaluate the methylation level of different CpG sites within DAPK1 promoter region in gliomas.
Based on sodium bisulfite treated DNA products, we made use of DNA pyrosequencing method to evaluate overall and site-specific methylation of DAPK1 in 143 gliomas and 26 benign tumors (meningeomas) or normal brain tissues. We both statistically analyzed the association between methylation levels of each CpG site and the clinicopathological characteristics, and estimated the prognosis predictive value of site-specific methylation for glioma patients.
Methylation status of DAPK1 site -1527, -1543, and the overall five sites concerned was higher in gliomas than controlled subjects (p < 0.001). Hypermethylation at site -1527 or together with site -1543 associated with better survival in patients taken postoperative therapies (-1527: p = 0.002; -1527 & -1543: p = 0.023), as well as in patients just underwent radiotherapy after surgery (-1527: p = 0.015; -1527 & -1543: p = 0.030). However, Cox regression analysis indicated the site-specific methylation was not independent contributor for gliomas prognosis.
Analysis of DAPK1 gene promoter by quantitative pyrosequencing provided more detailed information of methylation status of CpG sites. DAPK1 methylation level is associated with gliomas clinical features and outcomes. Interestingly, the hypermethylation at site -1527 or together with site -1543 indicated good sensitivity of postoperative therapies, especially radiotherapy. Thus, site specifically analysis of DAPK1 methylation may be a valuable diagnostic and prognostic estimation for gliomas.
已有报道称死亡相关蛋白激酶1（DAPK1）基因在包括神经胶质瘤在内的多种癌症中发生甲基化。然而，其对神经胶质瘤的预后价值仍存在争议，且尚未对DAPK1特定CpG位点的甲基化情况进行研究。本研究的目的是对神经胶质瘤中DAPK1启动子区域内不同CpG位点的甲基化水平进行预后评估。
基于亚硫酸氢钠处理的DNA产物，我们利用焦磷酸测序法评估了143例神经胶质瘤以及26例良性肿瘤（脑膜瘤）或正常脑组织中DAPK1的总体甲基化和位点特异性甲基化情况。我们对每个CpG位点的甲基化水平与临床病理特征之间的关联进行了统计学分析，并评估了位点特异性甲基化对神经胶质瘤患者的预后预测价值。
神经胶质瘤中DAPK1位点-1527、-1543以及相关的五个位点的总体甲基化状态高于对照受试者（p<0.001）。-1527位点或与-1543位点一起的高甲基化与接受术后治疗的患者（-1527：p=0.002；-1527和-1543：p=0.023）以及仅在手术后接受放疗的患者（-1527：p=0.015；-1527和-1543：p=0.030）的更好生存相关。然而，Cox回归分析表明位点特异性甲基化并非神经胶质瘤预后的独立影响因素。
通过定量焦磷酸测序分析DAPK1基因启动子可提供有关CpG位点甲基化状态的更详细信息。DAPK1甲基化水平与神经胶质瘤的临床特征和预后相关。有趣的是，-1527位点或与-1543位点一起的高甲基化表明术后治疗，尤其是放疗具有良好的敏感性。因此，对DAPK1甲基化进行位点特异性分析可能对神经胶质瘤具有有价值的诊断和预后评估作用。
