Rabideau Amy E, Liao Xiaoli, Pentelute Bradley L
Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Ave. 18-596 , Cambridge , MA 02139 , USA . Email:
Chem Sci. 2015 Jan 1;6(1):648-653. doi: 10.1039/c4sc02078b. Epub 2014 Sep 25.
Mirror image peptides have unique stability and immunogenic properties in mammals, making them attractive agents to investigate. Their properties inside cells have been mostly unexplored because biopolymers are difficult to transport across cellular membranes. Here, we used protective antigen (PA) from anthrax toxin to deliver mirror image polypeptide cargo into the cytosol of mammalian cells when conjugated to the C-terminus of the PA-binding domain of lethal factor, LF. We found mirror image polypeptides and proteins were translocated as efficiently into cells as their L counterparts. Once in the cytosol, by the use of western blot, we found that d peptides at the C-terminus of LF were able to achieve higher steady state concentrations when compared to the l-peptide conjugate. With this platform, we delivered a d-peptide MDM2 antagonist to disrupt the p53/MDM2 interaction in cancer cells. For the first time, we show the PA/LF system is adaptable for the intracellular delivery of mirror image peptides and proteins.
镜像肽在哺乳动物中具有独特的稳定性和免疫原性，使其成为有吸引力的研究对象。由于生物聚合物难以跨细胞膜转运，它们在细胞内的特性大多未被探索。在这里，我们使用炭疽毒素的保护性抗原（PA），当与致死因子LF的PA结合域的C末端偶联时，将镜像多肽货物递送至哺乳动物细胞的细胞质中。我们发现镜像多肽和蛋白质与它们的L对应物一样有效地转运到细胞中。一旦进入细胞质，通过蛋白质印迹法，我们发现与L-肽缀合物相比，LF C末端的d肽能够达到更高的稳态浓度。利用这个平台，我们递送了一种d肽MDM2拮抗剂，以破坏癌细胞中p53/MDM2的相互作用。我们首次证明PA/LF系统适用于镜像肽和蛋白质的细胞内递送。
