Shen Cheng-Huang, Li Pei-Yu, Wang Shou-Chieh, Wu Sin-Rong, Hsieh Chih-Yu, Dai Yuan-Chang, Liu Yi-Wen
Department of Urology, Ditmanson Medical Foundation Chiayi Christian Hospital, Chiayi, 600, Taiwan.
SKBIO Technology Corporation, Taipei, 114065, Taiwan.
Heliyon. 2023 May 1;9(5):e16004. doi: 10.1016/j.heliyon.2023.e16004. eCollection 2023 May.
WNT inhibitory factor 1 () is known to function as a tumor suppressor gene; it inhibits oncogene activation by preventing WNT signaling. This study investigated the epigenetic regulation of WIF1 gene in bladder cancer. We observed a positive relationship between WIF1 mRNA expression and survival probability of bladder cancer patients. The WIF1 gene expression could be enhanced by DNA demethylation drug 5-aza-2'-deoxycytidine (5-aza-dC) and histone deacetylase inhibitor trichostatin A (TSA), suggesting that epigenetic modifications could regulate WIF1 gene expression. Overexpression of WIF1 inhibited cell proliferation and migration in 5637 cells, confirming the tumor suppressor role of WIF1. 5-Aza-dC dose dependently increased WIF1 gene expression while reducing DNA methylation level, suggesting that reversing WIF1 DNA methylation could activate its gene expression. We collected the cancer tissues and urine pellets of bladder cancer patients and only urine pellets from non-bladder cancer volunteers for DNA methylation analysis, but the methylation level of gene -184 to +29 did not differ between patients and controls. We also analyzed glutathione -transferase Mu 5 (GSTM5) gene methylation level because GSTM5 DNA hypermethylation was suggested to be a tumor biomarker in our previous study. It confirmed a higher GSTM5 DNA methylation in bladder cancer patients than in controls. In summary, this study suggests that the 5-aza-dC activated WIF1 gene which showed an anti-cancer effect, while promoter -184 to +29 did not provide a suitable methylation assay region in clinical samples. In contrast, promoter -258 to -89 is a useful region for DNA methylation assay because it shows a higher methylation level in bladder cancer patients.
已知WNT抑制因子1（WIF1）作为一种肿瘤抑制基因发挥作用；它通过阻止WNT信号传导来抑制癌基因激活。本研究调查了膀胱癌中WIF1基因的表观遗传调控。我们观察到WIF1 mRNA表达与膀胱癌患者的生存概率之间存在正相关关系。DNA去甲基化药物5-氮杂-2'-脱氧胞苷（5-aza-dC）和组蛋白去乙酰化酶抑制剂曲古抑菌素A（TSA）可增强WIF1基因表达，这表明表观遗传修饰可调节WIF1基因表达。WIF1的过表达抑制了5637细胞的增殖和迁移，证实了WIF1的肿瘤抑制作用。5-aza-dC剂量依赖性地增加WIF1基因表达，同时降低DNA甲基化水平，这表明逆转WIF1 DNA甲基化可激活其基因表达。我们收集了膀胱癌患者的癌组织和尿沉渣以及非膀胱癌志愿者的尿沉渣用于DNA甲基化分析，但患者和对照组之间WIF1基因-184至+29区域的甲基化水平没有差异。我们还分析了谷胱甘肽-S-转移酶Mu 5（GSTM5）基因的甲基化水平，因为在我们之前的研究中，GSTM5 DNA高甲基化被认为是一种肿瘤生物标志物。结果证实，膀胱癌患者的GSTM5 DNA甲基化水平高于对照组。总之，本研究表明5-aza-dC激活了具有抗癌作用的WIF1基因，而WIF1基因启动子-184至+29区域在临床样本中不是合适的甲基化检测区域。相比之下，WIF1基因启动子-258至-89区域是DNA甲基化检测的有用区域，因为它在膀胱癌患者中显示出更高的甲基化水平。
