Transforming growth factor-β1 induces apoptosis in rat FaO hepatoma cells via cytochrome c release and oligomerization of Apaf-1 to form a ∼700-kd apoptosome caspase-processing complex
Transforming growth factor-β1 induces apoptosis in rat FaO hepatoma cells via cytochrome c release and oligomerization of Apaf-1 to form a ∼700-kd apoptosome caspase-processing complex
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DOI：
10.1053/jhep.2000.18329
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发表时间：
2000-10-01
期刊：
影响因子：
13.5
通讯作者：
Cain, K
中科院分区：
文献类型：
--
作者：
Freathy, C;Brown, DG;Cain, K
在哺乳动物细胞中，非受体介导的细胞凋亡是通过细胞色素c依赖性组装一个类似于700 kd凋亡蛋白酶激活因子1（Apaf-1）/半胱天冬酶9（caspase-9）的复合体来实现的。这启动了产后介导的效应物半胱天冬酶级联反应。我们现在发现受体介导的转化生长因子β 1（TGF-β 1）诱导的大鼠肝癌细胞凋亡伴随着半胱天冬酶-2、-3、-7和-8的加工和激活。此外，我们表明，caspase激活介导的细胞色素c的释放和寡聚化的Apaf-1成一个类似的700 kd的核糖体复合物。类似地，用2'-脱氧腺苷5'-三磷酸（dATP）体外活化肝癌细胞裂解物导致形成类似于700-kd的溶酶体复合物，其募集并加工半胱天冬酶-3和-7。泛半胱天冬酶抑制剂Z-VAD. FMK [苄氧基羰基-Val-Ala-Asp（OMe）氟甲基酮]完全抑制dATP刺激的半胱天冬酶活化，但不阻断含有大Apaf-1的核糖体复合物的组装。同样，在完整细胞中，尽管Z-VAD. FMK阻断了TGF-β 1诱导的凋亡，但它不能阻止Apaf-1寡聚化进入凋亡小体。然而，Z-VAD. FMK阻止了半胱天冬酶-3和-7的募集和加工。这些数据表明，TGF-β 1通过释放细胞色素c和激活Apaf-1溶酶体复合物（启动caspase级联反应）诱导细胞凋亡。
In mammalian cells, non receptor-mediated apoptosis occurs via the cytochrome c-dependent assembly of a similar to 700-kd apoptotic protease-activating factor 1 (Apaf-1)/ caspase-9 containing apoptosome complex. This initiates the postmitochondrial-mediated effector capase cascade. We now show that receptor mediated transforming growth factor beta(1) (TGF-beta(1))-induced apoptosis in rat hepatoma cells is accompanied by processing and activation of caspases-2, -3, -7, and -8. Furthermore, we show that caspase activation is mediated via the release of cytochrome c and the oligomerization of Apaf-1 into an similar to 700-kd apoptosome complex. Similarly, in vitro activation of hepatoma cell lysates with 2'-deoxyadenosine 5'-triphosphate (dATP) results in the formation of the similar to 700-kd apoptosome complex, which recruits and processes caspases-3 and -7. Z-VAD.FMK [benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone], the pan-caspase inhibitor totally inhibits dATP-stimulated caspase activation but does not block the assembly of the large Apaf-1 containing apoptosome complex. However, the recruitment and subsequent processing of caspases-3 and -7 to the apoptosome is blocked, Similarly, in intact cells, although Z-VAD.FMK blocked TGF-beta(1)-induced apoptosis, it did not prevent the oligomerization of Apaf-1 into the apoptosome. However, recruitment and processing of caspases-3 and -7 were prevented by Z-VAD.FMK. These data show that TGF-beta(1) induces apoptosis via release of cytochrome c and activation of the Apaf-1 apoptosome complex, which initiates the caspase cascade.