Amphipathic Tail-anchoring Peptide and Bcl-2 Homology Domain-3 (BH3) Peptides from Bcl-2 Family Proteins Induce Apoptosis through Different Mechanisms
Amphipathic Tail-anchoring Peptide and Bcl-2 Homology Domain-3 (BH3) Peptides from Bcl-2 Family Proteins Induce Apoptosis through Different Mechanisms
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DOI：
10.1074/jbc.m110.198457
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发表时间：
2011-03-18
影响因子：
4.8
通讯作者：
Ma, Jianjie
中科院分区：
文献类型：
--
作者：
Ko, Jae-Kyun;Choi, Kyoung-Han;Ma, Jianjie
Bcl-2同源结构域-3（BH 3）肽是靶向癌细胞中凋亡性细胞死亡的调节剂的有效癌症治疗试剂。然而，它们的细胞毒性作用受到Bcl-2家族蛋白的不同表达水平的影响。我们最近发现，两亲性尾锚定肽（ATAP）从Bfl-1，一个双功能Bcl-2家族成员，产生强大的促凋亡活性，通过透化线粒体外膜。在这里，我们测试ATAP的活性是否需要其他细胞因子，以及ATAP在靶向癌细胞方面是否比BH 3肽具有优势。共聚焦显微镜成像显示了ATAP对线粒体的特异性靶向，而BH 3肽显示了胞质分布的弥散模式。尽管BH 3肽的促凋亡活性在很大程度上被细胞中抗凋亡Bcl-2或Bcl-xL的过表达或促凋亡Bax和巴克的无效抑制，但ATAP的促凋亡功能不受这些细胞因子的影响。将合成的ATAP重组到脂质体膜中导致细胞色素c大小的荧光分子从脂质体中释放，这表明ATAP的膜透化活性不需要额外的蛋白质因子。由于ATAP可以靶向线粒体膜，并且其促凋亡活性不依赖于Bcl-2家族蛋白的含量，因此它代表了一种有希望的抗癌药物候选物，可以潜在地克服癌细胞内在的抗凋亡性质。
Bcl-2 homology domain-3 (BH3) peptides are potent cancer therapeutic reagents that target regulators of apoptotic cell death in cancer cells. However, their cytotoxic effects are affected by different expression levels of Bcl-2 family proteins. We recently found that the amphipathic tail-anchoring peptide (ATAP) from Bfl-1, a bifunctional Bcl-2 family member, produced strong pro-apoptotic activity by permeabilizing the mitochondrial outer membrane. Here, we test whether the activity of ATAP requires other cellular factors and whether ATAP has an advantage over the BH3 peptides in targeting cancer cells. Confocal microscopic imaging illustrates specific targeting of ATAP to mitochondria, whereas BH3 peptides show diffuse patterns of cytosolic distribution. Although the pro-apoptotic activities of BH3 peptides are largely inhibited by either overexpression of anti-apoptotic Bcl-2 or Bcl-xL or nullification of pro-apoptotic Bax and Bak in cells, the pro-apoptotic function of ATAP is not affected by these cellular factors. Reconstitution of synthetic ATAP into liposomal membranes results in release of fluorescent molecules of the size of cytochrome c from the liposomes, suggesting that the membrane permeabilizing activity of ATAP does not require additional protein factors. Because ATAP can target to the mitochondrial membrane and its pro-apoptotic activity does not depend on the content of Bcl-2 family proteins, it represents a promising candidate for anti-cancer drugs that can potentially overcome the intrinsic apoptosis-resistant nature of cancer cells.