Dai Youyi, Duan Huaxin, Duan Chaojun, Zhou Rongrong, He Yuxiang, Tu Qingsong, Shen Liangfang
Department of Oncology, Xiangya Hospital Central South University, PR China.
Department of Oncology, Hunan Provincial People's Hospital, PR China; The First Affiliated Hospital of Hunan Normal University, PR China.
Biochem Biophys Res Commun. 2016 Jan 15;469(3):430-6. doi: 10.1016/j.bbrc.2015.09.109. Epub 2015 Dec 17.
Epigenetic alteration induced loss function of the transcription factor 21 (TCF21) has been associated with different types of human cancers. However, the epigenetic regulation and molecular functions of TCF21 in colorectal cancer (CRC) remain unknown. In this study, TCF21 expression levels and methylation status of its promoter region in CRC cell lines (n = 5) and CRC tissues (n = 151) as well as normal colorectal mucosa (n = 30) were assessed by RTq-PCR and methylation analysis (methylation specific PCR, MSP and bisulfite sequencing PCR, BSP), respectively. The cellular functions of TCF21 on CRC cell proliferation, apoptosis, invasion and migration were investigated in vitro. Our data revealed that TCF21 was frequently silenced by promoter hypermethylation in both tested CRC cell lines and primary CRC, and correlation analysis between methylation status and clinicopathologic parameters found that TCF21 methylation was significantly correlated with lymph node invasion (P = 0.013), while no significant correlation was found in other parameters. In addition, demethylation treatment resulted in re-expression of TCF21 in CRC cell lines, and cellular function experiments revealed that restoration of TCF21 inhibited CRC cell proliferation, promoted apoptosis and suppressed cell invasion and migration, suggesting that TCF21 may function as a tumor suppressor gene, which is downregulated through promoter hypermethylation in CRC development.
表观遗传改变导致转录因子21（TCF21）功能丧失，这与不同类型的人类癌症有关。然而，TCF21在结直肠癌（CRC）中的表观遗传调控和分子功能仍不清楚。在本研究中，分别通过逆转录定量聚合酶链反应（RTq-PCR）和甲基化分析（甲基化特异性PCR、MSP以及亚硫酸氢盐测序PCR、BSP）评估了CRC细胞系（n = 5）、CRC组织（n = 151）以及正常结直肠黏膜（n = 30）中TCF21的表达水平及其启动子区域的甲基化状态。体外研究了TCF21对CRC细胞增殖、凋亡、侵袭和迁移的细胞功能。我们的数据显示，在测试的CRC细胞系和原发性CRC中，TCF21经常因启动子高甲基化而沉默，甲基化状态与临床病理参数之间的相关性分析发现，TCF21甲基化与淋巴结侵袭显著相关（P = 0.013），而在其他参数中未发现显著相关性。此外，去甲基化处理导致CRC细胞系中TCF21重新表达，细胞功能实验表明，TCF21的恢复抑制了CRC细胞增殖，促进了凋亡，并抑制了细胞侵袭和迁移，这表明TCF21可能作为一种肿瘤抑制基因发挥作用，在CRC发生发展过程中通过启动子高甲基化而下调。
