Bid truncation mediated by caspases-3 and-9 in vinorelbine-induced apoptosis
Bid truncation mediated by caspases-3 and-9 in vinorelbine-induced apoptosis
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DOI：
10.1007/s10495-008-0184-y
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发表时间：
2008-04-01
期刊：
影响因子：
7.2
通讯作者：
Tanuma, Sei-ichi
中科院分区：
文献类型：
--
作者：
Hayakawa, Akemi;Kawamoto, Yoshiyuki;Tanuma, Sei-ichi
长春瑞滨是临床上用于治疗非小细胞肺癌和乳腺癌的化疗长春花生物碱。我们研究了长春瑞滨诱导人t细胞淋巴瘤细胞凋亡的机制。虽然长春瑞滨诱导的DNA片段被Jurkat细胞中caspase- 9和-3的特异性肽抑制剂所抑制，但caspase-8缺乏会延缓长春瑞滨诱导的细胞凋亡。在vinoreline处理的细胞中也观察到caspase-8的活化，当caspase-3活性被一种特定的肽抑制剂Ac-DNLC-CHO阻断时，caspase-3活性降低。用拮抗Fas抗体阻断Fas受体不会影响长春瑞滨诱导的DNA断裂。这些结果表明，通过caspase-9介导的caspase-3激活caspase-8，而不是通过fas触发的信号，vinorelbin诱导的细胞凋亡得以增强。Western blot结果显示，vinorelbine可切割caspase-3、-9和-8，并减少线粒体细胞色素c的数量。Caspase-8缺乏可抑制所有这些事件。caspase-8的下游底物Bid在vinoreline处理的细胞中也被切割，但在caspase-8缺失的Jurkat细胞中也观察到Bid截断。重要的是，重组caspase- 3和-9以及caspase-8在体外直接切割重组Bid。这些结果表明caspase -3和-9参与了Bid截断，提示了长春瑞滨诱导细胞凋亡的新机制。
Vinorelbine is a chemotherapeutic vinca alkaloid clinically prescribed for non-small cell lung cancer and breast cancer. Here we studied the mechanism for vinorelbine-induced apoptosis in a human T-cell lymphoma. Although vinorelbine induces DNA fragmentation that is inhibited by specific peptide inhibitors for caspases-9 and -3 in Jurkat cells, caspase-8 deficiency retards vinorelbine-induced apoptosis. Activation of caspase-8 is also observed in vinorelbine-treated cells, and the activity is diminished when the caspase-3 activity is blocked by a specific peptide inhibitor, Ac-DNLC-CHO. Blocking of the Fas receptor with an antagonistic anti-Fas antibody does not affect vinorelbine-induced DNA fragmentation. These results suggest that vinorelbine-induced apoptosis is enhanced by the activation of caspase-8 via caspase-9-mediated activation of caspase-3, but not through a Fas-triggered signal. Western blotting suggests that vinorelbine cleaves caspase-3, -9 and -8 and reduces the amount of mitochondrial cytochrome c. Caspase-8 deficiency suppresses all of these events. A downstream substrate for caspase-8, Bid, is also cleaved in vinorelbine-treated cells, but the Bid truncation is also observed in caspase-8-deficient Jurkat cells. Importantly, recombinant caspases-3 and -9, as well as caspase-8, directly cleaves recombinant Bid in vitro. These results suggest that caspases-3 and -9 participate in Bid truncation, indicating a new mechanism for vinorelbine-induces apoptosis.