Boonsongserm Papatson, Angsuwatcharakon Phonthep, Puttipanyalears Charoenchai, Aporntewan Chatchawit, Kongruttanachok Narisorn, Aksornkitti Vitavat, Kitkumthorn Nakarin, Mutirangura Apiwat
Program of Medical Science, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
Oncol Lett. 2019 Sep;18(3):3039-3048. doi: 10.3892/ol.2019.10638. Epub 2019 Jul 18.
The secretions of cancer cells alter epigenetic regulation in cancer stromal cells. The present study investigated the methylation changes in white blood cells (WBCs) caused by the secretions of colorectal cancer (CRC) cells. Changes in the DNA methylation of peripheral blood mononuclear cells (PBMCs) from normal individuals co-cultured with CRC cells were estimated using a methylation microarray. These changes were then compared against the DNA methylation changes and mRNA levels observed in the WBCs of patients with CRC. Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 () and matrix metalloproteinase 9 () were selected to assess the DNA methylation of the WBCs from CRC patients using real-time methylation-specific PCR. The majority of the genes analyzed presented high levels of mRNA in the WBCs of the patients with CRC and DNA methylation in the co-cultured PBMCs. Intragenic methylation revealed the strongest association (P=8.52×10). For validation, and were selected and used to test WBCs from 32 patients with CRC and 57 normal controls. The intragenic methylation was commonly found (P<0.0001) with high sensitivity (90.63%) and high specificity (96.49%), and a positive predictive value of 93.33% and a negative predictive value of 93.22%. methylation was revealed to have lower sensitivity (30.00%) but higher specificity (97.92%). In addition to circulating WBCs, MMP9 protein expression was observed in infiltrating WBCs and the metastatic lymph nodes of patients with CRC. In conclusion, CRC cells secrete factors that induce genome wide DNA methylation changes in the WBCs of patients with CRC. These changes, including intragenic methylation in WBCs, are promising CRC biomarkers to be tested in future CRC screening studies.
癌细胞的分泌物会改变癌症基质细胞中的表观遗传调控。本研究调查了结直肠癌（CRC）细胞分泌物引起的白细胞（WBC）甲基化变化。使用甲基化微阵列估计与CRC细胞共培养的正常个体外周血单核细胞（PBMC）的DNA甲基化变化。然后将这些变化与CRC患者WBC中观察到的DNA甲基化变化和mRNA水平进行比较。选择原胶原赖氨酸2-氧代戊二酸5-双加氧酶1（）和基质金属蛋白酶9（），使用实时甲基化特异性PCR评估CRC患者WBC的DNA甲基化。分析的大多数基因在CRC患者的WBC中呈现高水平的mRNA，在共培养的PBMC中呈现DNA甲基化。基因内甲基化显示出最强的关联（P = 8.52×10）。为了进行验证，选择并用于检测32例CRC患者和57例正常对照的WBC。基因内甲基化普遍存在（P < 0.0001），具有高敏感性（90.63%）和高特异性（96.49%），阳性预测值为93.33%，阴性预测值为93.22%。甲基化显示敏感性较低（30.00%）但特异性较高（97.92%）。除了循环WBC外，在CRC患者的浸润性WBC和转移淋巴结中观察到MMP9蛋白表达。总之，CRC细胞分泌的因子可诱导CRC患者WBC中全基因组DNA甲基化变化。这些变化，包括WBC中的基因内甲基化，有望成为未来CRC筛查研究中有待测试的CRC生物标志物。
