Department of Public Health, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.
Department of Public Health, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.
Clin Epigenetics. 2022 Sep 5;14(1):111. doi: 10.1186/s13148-022-01328-1.
The novel long noncoding RNA MEF2C-AS1 has been identified to play suppressor roles during tumorigenesis. DNA methylation has a regulatory effect on gene expression in cancer initiation and progression. However, the methylation status of MEF2C-AS1 and its role in colorectal cancer (CRC) development remain unclear.
The expression and methylation levels of MEF2C-AS1 were systematically analyzed among 31 cancers with available qualified data in GEPIA and UCSC Xena databases. Then, the MEF2C-AS1 methylation status was firstly examined among 12 CRCs by Illumina Infinium MethylationEPIC BeadChip in in-house step 1 and further quantified among 48 CRCs by the MassARRAY method in in-house step 2. Subsequently, its methylation and expression levels were quantified among 81 non-advanced adenomas (NAAs), 81 advanced adenomas (AAs), and 286 CRCs using the MassARRAY method, and among 34 NAAs, 45 AAs, and 75 CRCs by qRT-PCR, in in-house step 3, respectively. The effect of MEF2C-AS1 methylation on CRC survival was analyzed by the Kaplan-Meier method. Additionally, in vitro cell proliferation, migration and invasion assays, and bioinformatics analysis were performed to explore the role of MEF2C-AS1 in colorectal carcinogenesis.
Lower expression and higher methylation of MEF2C-AS1 were found in CRC by online databases. In the comparisons of lesion tissues with adjacent normal tissues, MEF2C-AS1 hypermethylation of each individual site and mean level was found among CRC patients in in-house step 1 and step 2, more meaningfully, among NAA patients, AA patients, and CRC patients at all stages during colorectal carcinogenesis in in-house step 3 (all p < 0.05). Further comparisons demonstrated significant differences between CRC and NAA (p = 0.025), AA and NAA (p = 0.020). Moreover, MEF2C-AS1 hypermethylation was associated with poorer disease-specific survival of CRC patients (p = 0.044). In addition, hypermethylation and lower expression of MEF2C-AS1 were verified in RKO cells, and the MEF2C-AS1 overexpression significantly suppressed RKO cell proliferation, migration, and invasion.
The findings reveal that MEF2C-AS1 hypermethylation might be an early driven event during colorectal carcinogenesis. It might serve as a promising prognostic biomarker for CRC survival. Our study also indicates the potential tumor-suppressing role of MEF2C-AS1 in CRC.
新型长非编码 RNA MEF2C-AS1 已被鉴定在肿瘤发生过程中发挥抑制作用。DNA 甲基化对癌症起始和进展过程中的基因表达具有调节作用。然而，MEF2C-AS1 的甲基化状态及其在结直肠癌（CRC）发展中的作用仍不清楚。
在 GEPIA 和 UCSC Xena 数据库中，对 31 种癌症的 MEF2C-AS1 的表达和甲基化水平进行了系统分析。然后，通过 Illumina Infinium MethylationEPIC BeadChip 在内部步骤 1 中首先检测了 12 例 CRC 中的 MEF2C-AS1 甲基化状态，并在内部步骤 2 中通过 MassARRAY 方法进一步定量了 48 例 CRC 中的 MEF2C-AS1 甲基化状态。随后，通过 MassARRAY 方法分别在 81 例非高级腺瘤（NAAs）、81 例高级腺瘤（AAs）和 286 例 CRC 中以及在 34 例 NAAs、45 例 AAs 和 75 例 CRC 中进行了 MEF2C-AS1 甲基化和表达水平的定量，通过 qRT-PCR 在内部步骤 3 中分别进行了定量。通过 Kaplan-Meier 方法分析 MEF2C-AS1 甲基化对 CRC 生存的影响。此外，进行了体外细胞增殖、迁移和侵袭测定以及生物信息学分析，以探索 MEF2C-AS1 在结直肠发生中的作用。
在线数据库发现 CRC 中 MEF2C-AS1 的表达降低和甲基化升高。在与相邻正常组织的病变组织比较中，在内部步骤 1 和步骤 2 中发现每个个体位点和平均水平的 MEF2C-AS1 高甲基化在 CRC 患者中，在内部步骤 3 中在 NAA 患者、AA 患者和结直肠癌患者中，在结直肠癌变过程中具有更有意义的发现（均 p<0.05）。进一步的比较表明 CRC 与 NAA 之间存在显著差异（p=0.025），AA 与 NAA 之间存在显著差异（p=0.020）。此外，MEF2C-AS1 高甲基化与 CRC 患者的疾病特异性生存较差相关（p=0.044）。此外，在 RKO 细胞中验证了 MEF2C-AS1 的高甲基化和低表达，并且 MEF2C-AS1 的过表达显著抑制了 RKO 细胞的增殖、迁移和侵袭。
研究结果表明，MEF2C-AS1 高甲基化可能是结直肠癌变过程中的早期驱动事件。它可能作为 CRC 生存的有前途的预后生物标志物。我们的研究还表明 MEF2C-AS1 在 CRC 中具有潜在的肿瘤抑制作用。
