Julien Olivier, Kampmann Martin, Bassik Michael C, Zorn Julie A, Venditto Vincent J, Shimbo Kazutaka, Agard Nicholas J, Shimada Kenichi, Rheingold Arnold L, Stockwell Brent R, Weissman Jonathan S, Wells James A
Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, California, USA.
1] Department of Cellular and Molecular Pharmacology, University of California-San Francisco, San Francisco, California, USA. [2] Howard Hughes Medical Institute, University of California-San Francisco, San Francisco, California, USA.
Nat Chem Biol. 2014 Nov;10(11):969-76. doi: 10.1038/nchembio.1639. Epub 2014 Sep 28.
We previously discovered a small-molecule inducer of cell death, named 1541, that noncovalently self-assembles into chemical fibrils ('chemi-fibrils') and activates procaspase-3 in vitro. We report here that 1541-induced cell death is caused by the fibrillar rather than the soluble form of the drug. A short hairpin RNA screen reveals that knockdown of genes involved in endocytosis, vesicle trafficking and lysosomal acidification causes partial 1541 resistance. We confirm the role of these pathways using pharmacological inhibitors. Microscopy shows that the fluorescent chemi-fibrils accumulate in punctae inside cells that partially colocalize with lysosomes. Notably, the chemi-fibrils bind and induce liposome leakage in vitro, suggesting they may do the same in cells. The chemi-fibrils induce extensive proteolysis including caspase substrates, yet modulatory profiling reveals that chemi-fibrils form a distinct class from existing inducers of cell death. The chemi-fibrils share similarities with proteinaceous fibrils and may provide insight into their mechanism of cellular toxicity.
我们之前发现了一种名为1541的细胞死亡小分子诱导剂，它能非共价地自组装成化学纤维（“化学纤维”）并在体外激活procaspase-3。我们在此报告，1541诱导的细胞死亡是由药物的纤维状而非可溶性形式引起的。短发夹RNA筛选显示，敲低参与内吞作用、囊泡运输和溶酶体酸化的基因会导致对1541产生部分抗性。我们使用药理学抑制剂证实了这些途径的作用。显微镜检查显示，荧光化学纤维在细胞内的点状结构中积累，这些点状结构与溶酶体部分共定位。值得注意的是，化学纤维在体外能结合并诱导脂质体泄漏，表明它们在细胞中可能也会如此。化学纤维诱导广泛的蛋白水解，包括半胱天冬酶底物，但调节谱分析显示，化学纤维与现有的细胞死亡诱导剂形成了一个不同的类别。化学纤维与蛋白质纤维有相似之处，可能有助于深入了解它们的细胞毒性机制。
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