Wang Chun-lei, Wan Yuan-lian, Liu Yu-cun, Huang Zhi-qiang
Department of General Surgery, Peking University First Hospital, Beijing 100034, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2006 Apr 18;38(2):176-8.
To determine the relationships between apoptosis induced by transforming growth factor beta 1(TGF-beta1) and Smad in human hepatoma cell lines.
Three human hepatic carcinoma cell lines, involving different status of the p53 gene respectively, were used in this study. TGF-beta1-induced apoptosis in hepatic carcinoma cell lines was quantitated using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. For identification of the mechanism of apoptosis induced by TGF-beta1, these cell lines were transfected with a TGF-beta1-inducible luciferase reporter plasmid containing Smad binding elements (SBE) and luciferase gene using LF2000, then were treated with TGF-beta1. Relative luciferase activity was assayed respectively.
Among three cell lines studied with TUNEL assay, addition of TGF-beta1 induced apoptosis only in HepG2 cells (wild type p53). In contrast, Huh-7 (mutant p53) and Hep3B (deleted p53) cell lines lacked apoptosis. The detection of luciferase activity indicated that HepG2 cells dramatically increased the response to TGF-beta1 induction, Huh-7 and Hep3B cell lines significantly lowered luciferase expression.
HepG2 cells were highly susceptible to TGF-beta1-induced apoptosis compared with Hep3B and Huh-7 cell lines. Smad4 may be a central mediator of the TGF-beta1 signaling transduction pathway.
确定转化生长因子β1（TGF-β1）诱导的细胞凋亡与人类肝癌细胞系中Smad之间的关系。
本研究使用了三种分别涉及不同p53基因状态的人类肝癌细胞系。采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法（TUNEL法）对肝癌细胞系中TGF-β1诱导的细胞凋亡进行定量分析。为了确定TGF-β1诱导细胞凋亡的机制，使用LF2000将含有Smad结合元件（SBE）和荧光素酶基因的TGF-β1诱导型荧光素酶报告质粒转染至这些细胞系，然后用TGF-β1进行处理。分别检测相对荧光素酶活性。
在通过TUNEL法研究的三种细胞系中，添加TGF-β1仅在HepG2细胞（野生型p53）中诱导细胞凋亡。相比之下，Huh-7细胞（突变型p53）和Hep3B细胞（p53缺失）缺乏细胞凋亡现象。荧光素酶活性检测表明，HepG2细胞对TGF-β1诱导的反应显著增强，Huh-7和Hep3B细胞系的荧光素酶表达显著降低。
与Hep3B和Huh-7细胞系相比，HepG2细胞对TGF-β1诱导的细胞凋亡高度敏感。Smad4可能是TGF-β1信号转导通路的中心介质。
