Thymineless death in colon carcinoma cells is mediated via Fas signaling
Thymineless death in colon carcinoma cells is mediated via Fas signaling
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DOI：
10.1073/pnas.94.15.8144
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发表时间：
1997-07-22
影响因子：
11.1
通讯作者：
Tillman, DM
中科院分区：
文献类型：
--
作者：
Houghton, JA;Harwood, FG;Tillman, DM
Fas在结肠上皮细胞中组成型表达，并且也在结肠癌和培养的结肠癌细胞株中表达。然而，Fas信号转导在介导这种类型的细胞凋亡中的潜在作用仍然未知。我们已经开发了胸苷酸合成酶缺陷的人结肠癌细胞模型，其证明了在由无胸腺嘧啶应激诱导的DNA损伤后的急性（TS-细胞）或延迟（Thy 4细胞）凋亡。在dThd剥夺期间暴露于NOK-1单克隆抗体（抑制Fas信号传导）后，获得了对细胞免于急性凋亡和延迟凋亡的完全保护。这些结果表明，无胸腺嘧啶应激诱导的细胞凋亡是通过自分泌信号通过Fas-FasL相互作用调节的，Fas在TS-和Thy 4细胞中均高表达。然而，在同步培养中检测不到的FasL在TS-细胞中在48小时（当细胞经历急性凋亡时）和在Thy 4细胞中在96小时上调，与无胸腺嘧啶死亡的延迟开始相关，FasL表达也与亲本GC（3）/cl细胞中诱导的急性凋亡相关，在5-氟尿嘧啶/亚叶酸暴露抑制胸苷酸合成酶后48小时开始。Fas介导的细胞毒性抗Fas单克隆抗体CH-11诱导的细胞凋亡被抑制后，腺病毒递送的Bcl-2的cDNA，Bcl-2也保护细胞从急性凋亡诱导的dThd剥夺。总之，这些数据表明在这些培养的结肠癌细胞模型中有功能性Fas系统，并且它们表明Fas-FasL相互作用可以将无胸腺嘧啶应激诱导的DNA损伤与结肠癌细胞的凋亡机制联系起来。
Fas is expressed constitutively in colonic epithelial cells and is also expressed in colon carcinomas and in cultured colon carcinoma cell lints. However, the potential role of Fas signaling in mediating apoptosis in cells of this type remains unknown. We have developed human colon carcinoma cell models deficient in thymidylate synthase that demonstrate acute (TS- cells) or delayed (Thy4 cells) apoptosis following DNA damage induced by thymineless stress, Complete protection of cells from acute apoptosis and prolongation of delayed apoptosis was obtained following exposure to the NOK-1 monoclonal antibody (inhibitory to Fas signaling) during the period of dThd deprivation. These results suggested that apoptosis induced by thymineless stress was regulated by autocrine signaling via Fas-FasL interactions, Fas expression was high in both TS- and Thy4 cells, However, FasL, undetectable in synchronous cultures, was up-regulated in TS- cells at 48 hr, when cells were undergoing acute apoptosis, and in Thy4 cells at 96 hr, correlating with the delayed onset of thymineless death, FasL expression also correlated with acute apoptosis induced in parental GC(3)/cl cells, commencing at 48 hr, following thymidylate synthase inhibition by 5-fluorouracil/leucovorin exposure. Fas-mediated apoptosis induced by the cytotoxic anti-Fas monoclonal antibody CH-11 was inhibited following adenoviral delivery of a Bcl-2 cDNA, and Bcl-2 also protected cells from acute apoptosis induced by dThd deprivation. Taken together, these data demonstrate a functional Fas system in these cultured colon carcinoma fell models, and they demonstrate that Fas-FasL interactions can link DNA damage induced by thymineless stress to the apoptotic machinery of colon carcinoma cells.