Positive regulation of spondin 2 by thyroid hormone is associated with cell migration and invasion.
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.
Liao
Chen-Hsin
CH
Department of Biochemistry, School of Medicine, Chang-Gung University, 259 Wen-hwa 1st Road, Taoyuan 333, Taiwan, Republic of China.
Yeh
Shih-Chi
SC
Huang
Ya-Hui
YH
Chen
Ruey-Nan
RN
Tsai
Ming-Ming
MM
Chen
Wei-Jan
WJ
Chi
Hsiang-Cheng
HC
Tai
Pei-Ju
PJ
Liao
Chia-Jung
CJ
Wu
Sheng-Ming
SM
Cheng
Wan-Li
WL
Pai
Li-Mei
LM
Lin
Kwang-Huei
KH
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D055785:Gene Knockdown Techniques; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D012334:RNA, Neoplasm / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011988:Receptors, Thyroid Hormone / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D013965:Thyroidectomy; D014284:Triiodothyronine / Q000494:pharmacology / Q000502:physiology*
D016326:Extracellular Matrix Proteins; D036341:Intercellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D010455:Peptides; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011988:Receptors, Thyroid Hormone; D011993:Recombinant Fusion Proteins; C122166:SPON2 protein, human; C498955:Spon1 protein, rat; D014284:Triiodothyronine