Targeted Polypeptide-Microtubule Aggregation with Cucurbit[8]uril for Enhanced Cell Apoptosis.

Tunable protein assemblies not only hold a dominant position in vital biological events but are also a significant theme in supramolecular chemistry. Herein, we demonstrated that the intertubular aggregation of microtubules (MTs) could be efficiently regulated by a synergistic polypeptide-tubulin interaction and host-guest complexation. The benzylimidazolium-modified antimitotic peptide (BP) could recognize the MTs and concurrently form stable inclusion complexes with avirulent cucurbit[7]uril (CB[7]) and cucurbit[8]uril (CB[8]) in different binding stoichiometries. The self-assembling morphology of MTs was converted from fibrous to nanoparticulate aggregates via extensive BP⊂CB[8] cross-linkage, leading to significant cell apoptosis and tumor ablation in vivo. The targeted (BP⊂CB[8])@MT ternary assembly provides a facile supramolecular method to enhance the protein-protein interactions, which may be developed as a therapy for degenerative diseases, such as cancer.