Watkins P J, Condreay J P, Huber B E, Jacobs S J, Adams D J
Division of Cell Biology, Wellcome Research Laboratories, Research Triangle Park, North Carolina 27709, USA.
Cancer Res. 1996 Mar 1;56(5):1063-7.
A plasmid containing the CCAAT/enhancer-binding protein (C/EBP alpha) gene transcriptionally controlled by the metallothionein promoter was constructed. The gene was transfected into the human hepatocellular carcinoma cell lines Hep3B and HepG2. When cultured in vitro in the presence of 100 microM ZnSO(4), C/EBP alpha expression caused reversible growth arrest. In soft agar clonogenic assays, C/EBP alpha expression decreased both the colony size and the total number of colonies compared with zinc-free controls. C/EBP alpha expressing cells s.c. implanted in CD-1 nu/nu mice were essentially nontumorigenic, whereas C/EBP alpha tumor cells implanted into immunodeficient SCID mice demonstrated a significantly delayed time of tumor appearance compared with cells transfected with a vector control plasmid. These studies suggest that the expression of endogenous genes normally associated with a quiescent, differentiated state, such as C/EBP alpha, can result in impaired proliferative activity and suppressed tumorigenicity of hepatoma cell lines.
构建了一个含有受金属硫蛋白启动子转录控制的CCAAT/增强子结合蛋白（C/EBPα）基因的质粒。该基因被转染到人肝癌细胞系Hep3B和HepG2中。当在含有100微摩尔硫酸锌的条件下进行体外培养时，C/EBPα的表达导致可逆性生长停滞。在软琼脂克隆形成试验中，与无锌对照相比，C/EBPα的表达降低了集落大小和集落总数。皮下植入CD-1裸鼠的表达C/EBPα的细胞基本无致瘤性，而植入免疫缺陷SCID小鼠的C/EBPα肿瘤细胞与用载体对照质粒转染的细胞相比，肿瘤出现时间显著延迟。这些研究表明，正常与静止、分化状态相关的内源性基因如C/EBPα的表达可导致肝癌细胞系增殖活性受损和致瘤性受抑制。
