Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China.
Department of Anesthesia Surgery, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China.
Clin Res Hepatol Gastroenterol. 2021 Nov;45(6):101725. doi: 10.1016/j.clinre.2021.101725. Epub 2021 Jun 3.
Teashirt zinc finger homeobox 3 (TSHZ3) is currently reported to be aberrantly expressed in several tumors, but the detailed functions and epigenetic mechanisms of TSHZ3 in colorectal cancer (CRC) remain unclear.
In this study, the TSHZ3 expression in 118 CRC and normal adjacent tissues (NATs) was evaluated, and the methylation status of the TSZH3 promoter region in CRC tissues and cell lines was also analyzed.
The results of PCR analysis showed that TSHZ3 was significantly down-regulated in CRC tissues, and patients with low TSHZ3 levels had a poorer 5-year overall survival (OS) rate. Analyzing the promoter sequence (-1000∼0) by MethPrimer, TSHZ3 promoter was found to harbor abundant of CpG islands. The methylation specific PCR (MSP) analysis presented a relatively hypermethylated status of THSZ3 promoter in CRC samples. The data of MSP and bisulfite sequencing PCR (BSP) also confirmed that CpG sites of TSHZ3 promoter were methylated in CRC cells, and the DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-Aza) could effectively restored the TSHZ3 expression in vitro. Functionally, the proliferation, apoptosis and metastasis of CRC cells were regulated by TSZH3 over-expression, and the suppressing effects of TSHZ3 in CRC were also confirmed in a xenograft mouse model.
Our results indicated that promoter methylation was one of the mechanisms contributing to the down-regulation of TSHZ3 in CRC, and TSZH3 might served as a potential tumor suppressor gene in the development and progression of CRC.
目前报道 Tea 衬衫锌指同源盒 3（TSHZ3）在几种肿瘤中表达异常，但 TSHZ3 在结直肠癌（CRC）中的详细功能和表观遗传机制仍不清楚。
本研究评估了 118 例 CRC 和正常相邻组织（NAT）中 TSHZ3 的表达，并分析了 CRC 组织和细胞系中 TSHZ3 启动子区域的甲基化状态。
PCR 分析结果表明，TSHZ3 在 CRC 组织中显著下调，低 TSHZ3 水平的患者 5 年总生存率（OS）较低。通过 MethPrimer 分析启动子序列（-1000∼0），发现 TSHZ3 启动子含有丰富的 CpG 岛。甲基化特异性 PCR（MSP）分析显示 CRC 样本中 TSHZ3 启动子呈相对高甲基化状态。MSP 和亚硫酸氢盐测序 PCR（BSP）的数据也证实 CRC 细胞中 TSHZ3 启动子的 CpG 位点发生甲基化，DNA 甲基转移酶（DNMT）抑制剂 5-氮杂-2'-脱氧胞苷（5-Aza）可有效恢复体外 TSHZ3 的表达。功能上，CRC 细胞的增殖、凋亡和转移受 TSZH3 过表达的调节，在异种移植小鼠模型中也证实了 TSHZ3 在 CRC 中的抑制作用。
我们的结果表明，启动子甲基化是导致 CRC 中 TSHZ3 下调的机制之一，TSHZ3 可能在 CRC 的发生和发展中作为潜在的肿瘤抑制基因。
