Yamamoto T, Gotoh M, Kitajima M, Hirohashi S
Pathology Division, National Cancer Center Research Institute, Tokyo, Japan.
Biochem Biophys Res Commun. 1993 Jun 15;193(2):706-10. doi: 10.1006/bbrc.1993.1682.
We constructed a "non-metastatic cell (SW837)--metastatic cell (PMCO1)" subtraction library and identified one cDNA that was strongly expressed in SW837 but weakly expressed in PMCO1. The nucleotide sequence of the cDNA revealed that it encoded thymosin beta-4. Four non-metastatic cell lines, which produced no experimental liver metastasis in nude mice, showed high expression of thymosin beta-4. However three of four metastatic cell lines showed weak expression of thymosin beta-4. Among surgical materials, thymosin beta-4 expression was high in tumors without metastasis in comparison with non-tumorous mucosa, but one case with liver metastasis showed decreased expression in both the primary and metastatic tumors. We suspect that down-regulation of thymosin beta-4 expression is correlated with the metastatic capacity of colorectal carcinomas.
我们构建了一个“非转移细胞（SW837）-转移细胞（PMCO1）”消减文库，并鉴定出一个在SW837中高表达而在PMCO1中低表达的cDNA。该cDNA的核苷酸序列显示其编码胸腺素β-4。四个在裸鼠中未产生实验性肝转移的非转移细胞系显示出胸腺素β-4的高表达。然而，四个转移细胞系中的三个显示出胸腺素β-4的低表达。在手术材料中，与非肿瘤黏膜相比，无转移肿瘤中胸腺素β-4的表达较高，但有一例肝转移病例在原发肿瘤和转移肿瘤中均显示表达降低。我们推测胸腺素β-4表达的下调与结直肠癌的转移能力相关。
