Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02454 , United States.
Department of Biology , Brandeis University , 415 South Street , Waltham , Massachusetts 02454 , United States.
J Am Chem Soc. 2018 Aug 1;140(30):9566-9573. doi: 10.1021/jacs.8b04641. Epub 2018 Jul 24.
The endoplasmic reticulum (ER) is responsible for the synthesis and folding of a large number of proteins, as well as intracellular calcium regulation, lipid synthesis, and lipid transfer to other organelles, and is emerging as a target for cancer therapy. However, strategies for selectively targeting the ER of cancer cells are limited. Here we show that enzymatically generated crescent-shaped supramolecular assemblies of short peptides disrupt cell membranes and target ER for selective cancer cell death. As revealed by sedimentation assay, the assemblies interact with synthetic lipid membranes. Live cell imaging confirms that the assemblies impair membrane integrity, which is further supported by lactate dehydrogenase (LDH) assays. According to transmission electron microscopy (TEM), static light scattering (SLS), and critical micelle concentration (CMC), attaching an l-amino acid at the C-terminal of a d-tripeptide results in the crescent-shaped supramolecular assemblies. Structure-activity relationship suggests that the crescent-shaped morphology is critical for interacting with membranes and for controlling cell fate. Moreover, fluorescent imaging indicates that the assemblies accumulate on the ER. Time-dependent Western blot and ELISA indicate that the accumulation causes ER stress and subsequently activates the caspase signaling cascade for cell death. As an approach for in situ generating membrane binding scaffolds (i.e., the crescent-shaped supramolecular assemblies), this work promises a new way to disrupt the membrane and to target the ER for developing anticancer therapeutics.
内质网 (ER) 负责大量蛋白质的合成和折叠，以及细胞内钙调节、脂质合成和脂质向其他细胞器的转移，并且正成为癌症治疗的靶点。然而，针对癌细胞 ER 的选择性靶向策略有限。在这里，我们展示了由短肽酶促生成的新月形超分子组装体破坏细胞膜，并针对 ER 实现选择性癌细胞死亡。如沉降测定所揭示的，这些组装体与合成脂质膜相互作用。活细胞成像证实了这些组装体破坏了膜的完整性，这进一步得到了乳酸脱氢酶 (LDH) 测定的支持。根据透射电子显微镜 (TEM)、静态光散射 (SLS) 和临界胶束浓度 (CMC)，在 d-三肽的 C 末端连接 l-氨基酸会导致新月形超分子组装体的形成。结构-活性关系表明，新月形形态对于与膜相互作用和控制细胞命运至关重要。此外，荧光成像表明这些组装体在内质网上积累。时程依赖性 Western blot 和 ELISA 表明，这种积累会导致内质网应激，随后激活 caspase 信号级联反应导致细胞死亡。作为一种用于原位生成膜结合支架的方法（即新月形超分子组装体），这项工作有望为开发抗癌治疗药物提供一种破坏膜并针对 ER 的新方法。
