2nd Department of Urology, Aristotle University of Thessaloniki, General Hospital 'Papageorgiou', 56403 Thessaloniki, Greece.
Department of Biological Chemistry, Medical School, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Int J Mol Sci. 2024 May 23;25(11):5660. doi: 10.3390/ijms25115660.
DNA methylation is an epigenetic process that commonly occurs in genes' promoters and results in the transcriptional silencing of genes. DNA methylation is a frequent event in bladder cancer, participating in tumor initiation and progression. Bladder cancer is a major health issue in patients suffering from neurogenic lower urinary tract dysfunction (NLUTD), although the pathogenetic mechanisms of the disease remain unclear. In this population, bladder cancer is characterized by aggressive histopathology, advanced stage during diagnosis, and high mortality rates. To assess the DNA methylation profiles of five genes' promoters previously known to be associated with bladder cancer in bladder tissue of NLUTD patients, we conducted a prospective study recruiting NLUTD patients from the neuro-urology unit of a public teaching hospital. Cystoscopy combined with biopsy for bladder cancer screening was performed in all patients following written informed consent being obtained. Quantitative methylation-specific PCR was used to determine the methylation status of RASSF1, RARβ, DAPK, hTERT, and APC genes' promoters in bladder tissue samples. Twenty-four patients suffering from mixed NLUTD etiology for a median duration of 10 (IQR: 12) years were recruited in this study. DNA hypermethylation was detected in at least one gene of the panel in all tissue samples. RAR-β was hypermethylated in 91.7% samples, RASSF and DAPK were hypermethylated in 83.3% samples, APC 37.5% samples, and TERT in none of the tissue samples. In 45.8% of the samples, three genes of the panel were hypermethylated, in 29.2% four genes were hypermethylated, and in 16.7% and in 8.3% of the samples, two and one gene were hypermethylated, respectively. The number of hypermethylated genes of the panel was significantly associated with recurrent UTIs ( = 0.0048). No other significant association was found between DNA hypermethylation or the number of hypermethylated genes and the clinical characteristics of the patients. Histopathological findings were normal in 8.3% of patients, while chronic inflammation was found in 83.3% of patients and squamous cell metaplasia in 16.7% of patients. In this study, we observed high rates of DNA hypermethylation of genes associated with bladder cancer in NLUTD patients, suggesting an epigenetic field effect and possible risk of bladder cancer development. Recurrent UTIs seem to be associated with increased DNA hypermethylation. Further research is needed to evaluate the impact of recurrent UTIs and chronic inflammation in DNA hypermethylation and bladder cancer etiopathogenesis in NLUTD patients.
DNA 甲基化是一种常见于基因启动子的表观遗传过程，导致基因转录沉默。DNA 甲基化是膀胱癌的一个常见事件，参与肿瘤的起始和进展。膀胱癌是患有神经源性下尿路功能障碍 (NLUTD) 患者的一个主要健康问题，尽管疾病的发病机制仍不清楚。在这一人群中，膀胱癌的组织病理学表现具有侵袭性，诊断时处于晚期，死亡率较高。为了评估五个已知与膀胱癌相关的基因启动子的 DNA 甲基化谱在 NLUTD 患者膀胱组织中的情况，我们进行了一项前瞻性研究，招募了来自一所公立教学医院神经泌尿科的 NLUTD 患者。所有患者均在获得书面知情同意后接受膀胱镜检查和膀胱癌筛查活检。采用定量甲基化特异性 PCR 检测膀胱组织样本中 RASSF1、RARβ、DAPK、hTERT 和 APC 基因启动子的甲基化状态。本研究共纳入 24 例混合性 NLUTD 病因患者，中位病程 10（IQR：12）年。在所有组织样本中，至少有一个基因的 DNA 发生了过度甲基化。91.7%的样本中 RAR-β 发生过度甲基化，83.3%的样本中 RASSF 和 DAPK 发生过度甲基化，37.5%的样本中 APC 发生过度甲基化，而 TERT 则未发生在任何组织样本中。在 45.8%的样本中，有三个基因发生过度甲基化，在 29.2%的样本中，有四个基因发生过度甲基化，在 16.7%和 8.3%的样本中，分别有两个和一个基因发生过度甲基化。基因 panel 中过度甲基化基因的数量与复发性 UTIs 显著相关（=0.0048）。未发现 DNA 过度甲基化或过度甲基化基因数量与患者临床特征之间存在其他显著相关性。8.3%的患者组织学表现正常，83.3%的患者存在慢性炎症，16.7%的患者存在鳞状细胞化生。在本研究中，我们观察到 NLUTD 患者中与膀胱癌相关的基因存在高频率的 DNA 过度甲基化，提示存在表观遗传场效应和可能的膀胱癌发展风险。复发性 UTIs 似乎与 DNA 过度甲基化增加有关。需要进一步研究来评估复发性 UTIs 和慢性炎症对 NLUTD 患者 DNA 过度甲基化和膀胱癌发病机制的影响。
