Thanou Eleni, Lontra Dora, Balgouranidou Ioanna, Efthimiadou Eleni, Delipetrou Alexandra, Tsaroucha Emilia, Theodosiou Maria, Georgoulias Vassilis, Kotsakis Athanasios, Lianidou Evi, Markou Athina
Analysis of Circulating Tumor Cells, Laboratory of Analytical Chemistry, Department of Chemistry, University of Athens, 15771 Athens, Greece.
Department of Medical Oncology, University General Hospital of Alexandroupolis, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece.
Biomolecules. 2024 Nov 27;14(12):1514. doi: 10.3390/biom14121514.
Liquid biopsy enables real-time monitoring of tumor development and response to therapy through the analysis of CTCs and ctDNA. NALCN is a sodium leak channel that is frequently involved in tumor evolution and immunity and acts as a tumor suppressor. Deletion of NALCN has been shown to increase cancer metastasis and the number of CTCs in peripheral blood. In this study, we investigated for the first time NALCN promoter methylation in (a) Aza-treated cell lines (A549, TE671, BT20, and MDA-MB-468), (b) paired NSCLC tissues (n = 22), and (c) plasma cell-free DNA (ctDNA) from patients with NSCLC (early stage n = 39, metastatic n = 39) and DNA from 10 healthy donors (HD) using a newly developed highly specific and sensitive real-time MSP method. Treatment with 5'-aza-dC induced the expression of NALCN only in the A549 cell line, suggesting that DNA methylation regulates its expression in certain cancers. The mRNA expression levels of NALCN were quantified in non-small cell lung cancer (NSCLC) and adjacent non-cancerous tissues, and it was found to be underexpressed in 54.5% of tumor tissues, with significantly higher expression in recurrence-free patients ( = 0.009) than in patients who relapsed. The NALCN methylation level was not statisticallysignificantlycorrelated with the corresponding expression ( = 0.439), while Kaplan-Meier analysis showed an association between NALCN promoter hypermethylation and worse disease-free intervals (DFIs) ( = 0.017). Evaluation of NALCN methylation in ctDNA revealed that it was detected in 5.1% of early and 10.2% of advanced cases. Our results strongly suggest that epigenetic inactivation of NALCN may be a predictor of metastasis in NSCLC. Our results should be validated in further studies based on a larger patient cohort to further investigate whether DNA methylation of the NALCN promoter could serve as a potential prognostic DNA methylation biomarker and predictor of metastasis in NSCLC.
液体活检能够通过分析循环肿瘤细胞（CTCs）和循环肿瘤DNA（ctDNA）对肿瘤发展和治疗反应进行实时监测。NALCN是一种钠渗漏通道，经常参与肿瘤演变和免疫过程，并作为一种肿瘤抑制因子发挥作用。已表明NALCN的缺失会增加癌症转移以及外周血中循环肿瘤细胞的数量。在本研究中，我们首次使用新开发的高特异性和高灵敏度实时甲基化特异性PCR（MSP）方法，对以下样本进行了NALCN启动子甲基化研究：（a）经氮杂胞苷（Aza）处理的细胞系（A549、TE671、BT20和MDA-MB-468）；（b）配对的非小细胞肺癌（NSCLC）组织（n = 22）；（c）来自NSCLC患者（早期n = 39，转移期n = 39）的血浆游离DNA（ctDNA）以及来自10名健康供体（HD）的DNA。用5'-氮杂-2'-脱氧胞苷（5'-aza-dC）处理仅在A549细胞系中诱导了NALCN的表达，这表明DNA甲基化在某些癌症中调节其表达。对非小细胞肺癌（NSCLC）和相邻非癌组织中NALCN的mRNA表达水平进行了定量，发现54.5%的肿瘤组织中其表达不足，无复发患者中的表达显著高于复发患者（P = 0.009）。NALCN甲基化水平与相应表达无统计学显著相关性（P = 0.439），而Kaplan-Meier分析显示NALCN启动子高甲基化与更差的无病生存期（DFIs）之间存在关联（P = 0.017）。对ctDNA中NALCN甲基化的评估显示，在5.1%的早期病例和10.2%的晚期病例中检测到了该甲基化。我们的结果强烈表明，NALCN的表观遗传失活可能是非小细胞肺癌转移的一个预测指标。我们的结果应在基于更大患者队列的进一步研究中得到验证，以进一步研究NALCN启动子的DNA甲基化是否可作为非小细胞肺癌潜在的预后DNA甲基化生物标志物和转移预测指标。
