Department of Biochemistry, School of Medicine, Chang-Gung University, 259 Wen-hwa 1st Road, Taoyuan 333, Taiwan, Republic of China.
Endocr Relat Cancer. 2010 Jan 29;17(1):99-111. doi: 10.1677/ERC-09-0050. Print 2010 Mar.
The thyroid hormone 3,3',5-triiodo-L-thyronine (T(3)) regulates growth, development, and differentiation processes in animals. These activities are mediated by the nuclear thyroid hormone receptors (TRs). Microarray analyses were performed previously to study the mechanism of regulation triggered by T(3) treatment in hepatoma cell lines. The results showed that spondin 2 was regulated positively by T(3). However, the underlying mechanism and the physiological role of T(3) in the regulation of spondin 2 are not clear. To verify the microarray results, spondin 2 was further investigated using semi-quantitative reverse transcription-PCR and western blotting. After 48 h of T(3) treatment in the HepG2-TR alpha 1#1 cell line, spondin 2 mRNA and protein levels increased by 3.9- to 5.7-fold. Similar results were observed in thyroidectomized rats. To localize the regulatory region in spondin 2, we performed serial deletions of the promoter and chromatin immunoprecipitation assays. The T(3) response element on the spondin 2 promoter was localized in the -1104/-1034 or -984/-925 regions. To explore the effect of spondin 2 on cellular function, spondin 2 knockdown cell lines were established from Huh7 cells. Knockdown cells had higher migration ability and invasiveness compared with control cells. Conversely, spondin 2 overexpression in J7 cells led to lower migration ability and invasiveness compared with control cells. Furthermore, this study demonstrated that spondin 2 overexpression in some types of hepatocellular carcinomas is TR dependent. Together, these experimental findings suggest that spondin 2, which is regulated by T(3), has an important role in cell invasion, cell migration, and tumor progression.
甲状腺激素 3,3',5-三碘-L-甲状腺素 (T(3)) 调节动物的生长、发育和分化过程。这些活动是由核甲状腺激素受体 (TRs) 介导的。先前进行了微阵列分析，以研究 T(3)处理在肝癌细胞系中触发的调节机制。结果表明，T(3)正向调节 Spondin 2。然而，T(3)调节 Spondin 2 的潜在机制和生理作用尚不清楚。为了验证微阵列结果，使用半定量逆转录-PCR 和 Western blot 进一步研究了 Spondin 2。在 HepG2-TR alpha 1#1 细胞系中用 T(3)处理 48 小时后，Spondin 2 mRNA 和蛋白水平增加了 3.9-至 5.7 倍。在甲状腺切除大鼠中也观察到类似的结果。为了定位 Spondin 2 的调节区域，我们进行了启动子的串联缺失和染色质免疫沉淀测定。Spondin 2 启动子上的 T(3)反应元件位于-1104/-1034 或-984/-925 区域。为了探索 Spondin 2 对细胞功能的影响，从 Huh7 细胞中建立了 Spondin 2 敲低细胞系。与对照细胞相比，敲低细胞具有更高的迁移和侵袭能力。相反，与对照细胞相比，J7 细胞中 Spondin 2 的过表达导致迁移和侵袭能力降低。此外，本研究表明，某些类型的肝细胞癌中 Spondin 2 的过表达依赖于 TR。总之，这些实验结果表明，受 T(3)调节的 Spondin 2 在细胞侵袭、细胞迁移和肿瘤进展中具有重要作用。
