Hu Haochang, Wang Tiangong, Pan Ranran, Yang Yong, Li Bin, Zhou Cong, Zhao Jun, Huang Yi, Duan Shiwei
Medical Genetics Center, School of Medicine, Ningbo University, Ningbo, Zhejiang, China.
Department of Neurosurgery of Ningbo First Hospital, Ningbo University School of Medicine, Ningbo, Zhejiang, China.
Pathol Oncol Res. 2019 Apr;25(2):567-575. doi: 10.1007/s12253-018-0505-6. Epub 2018 Oct 27.
Colorectal cancer (CRC) is one of the leading causes of death worldwide. Aberrant DNA methylation has been recognized as one of the most common molecular alterations in CRC. The goal of this study was to investigate the diagnostic value of SFRP1 and SFRP2 methylation for CRC. A total of 80 pairs of CRC patients were recruited to test the association of SFRP1 and SFRP2 promotor methylation with CRC. Methylation assay was performed using quantitative methylation-specific polymerase chain reaction (qMSP) method. In this study, we found the methylation levels of SFRP1 and SFRP2 in CRC tumor tissues were significantly higher than those in the adjacent non-tumor tissues (SFRP1: P = 2E-5; SFRP2: P = 0.014). Further bioinformatics analysis of TCGA data confirmed the association of the two genes with CRC (SFRP1: P = 7E-21; SFRP2: P = 5E-24). Luciferase reporter gene assay showed that the recombinant plasmids with SFRP1 and SFRP2 fragments could significantly enhance promoter activity (SFRP1: P = 0.002; SFRP2: P = 0.004). In addition, SFRP1 and SFRP2 methylation were inversely correlated with the mRNA expression displayed by TCGA data mining (SFRP1: r = -0.432, P = 4E-11; SFRP2: r = -0.478, P = 1E-13). GEO data analysis indicated that SFRP1 and SFRP2 expression were increased in three CRC cell lines (COLO320, HCT116 and HT29) after 5'-AZA-deoxycytidine treatment, suggesting that DNA methylation played an important role in regulating gene expression of the two genes. Our results confirmed that promoter methylation of SFRP1 and SFRP2 contributed to the risk of CRC.
结直肠癌（CRC）是全球主要的死亡原因之一。异常DNA甲基化已被认为是CRC中最常见的分子改变之一。本研究的目的是探讨SFRP1和SFRP2甲基化对CRC的诊断价值。共招募了80对CRC患者来检测SFRP1和SFRP2启动子甲基化与CRC的相关性。采用定量甲基化特异性聚合酶链反应（qMSP）方法进行甲基化检测。在本研究中，我们发现CRC肿瘤组织中SFRP1和SFRP2的甲基化水平显著高于相邻的非肿瘤组织（SFRP1：P = 2E - 5；SFRP2：P = 0.014）。对TCGA数据的进一步生物信息学分析证实了这两个基因与CRC的相关性（SFRP1：P = 7E - 21；SFRP2：P = 5E - 24）。荧光素酶报告基因检测表明，带有SFRP1和SFRP2片段的重组质粒可显著增强启动子活性（SFRP1：P = 0.002；SFRP2：P = 0.004）。此外，通过对TCGA数据挖掘发现，SFRP1和SFRP2甲基化与mRNA表达呈负相关（SFRP1：r = -0.432，P = 4E - 11；SFRP2：r = -0.478，P = 1E - 13）。GEO数据分析表明，5'-氮杂-2'-脱氧胞苷处理后，三种CRC细胞系（COLO320、HCT116和HT29）中SFRP1和SFRP2的表达增加，这表明DNA甲基化在调节这两个基因的表达中起重要作用。我们的结果证实，SFRP1和SFRP2的启动子甲基化增加了CRC的发病风险。
