Enzyme-Activatable Polypeptide for Plasma Membrane Disruption and Antitumor Immunity Elicitation.

ABSTRACT

Enzyme-instructed self-assembly of bioactive molecules into nanobundles inside cells is conceived to potentially disrupt plasma membrane and subcellular structure. Herein, an alkaline phosphatase (ALP)-activatable hybrid of ICG-CF4 KYp is facilely synthesized by conjugating photosensitizer indocyanine green (ICG) with CF4 KYp peptide via classical Michael addition reaction. ALP-induced dephosphorylation of ICG-CF4 KYp enables its transformation from small-molecule precursor into rigid nanofibrils, and such fibrillation in situ causes severe mechanical disruption of cytomembrane. Besides, ICG-mediated photosensitization causes additional oxidative damage of plasma membrane by lipid peroxidation. Hollow MnO2 nanospheres devote to deliver ICG-CF4 KYp into tumorous tissue through tumor-specific acidity/glutathione-triggered degradation of MnO2 , which is monitored by fluorescent probing and magnetic resonance imaging. The burst release of damage-associated molecular patterns and other tumor antigens during therapy effectively triggers immunogenetic cell death and improves immune stimulatory, as demonstrated by the promotion of dendritic cell maturation and CD8+ lymphocyte infiltration, as well as constraint of regulatory T cell population. Taken together, such cytomembrane injury strategy based on peptide fibrillation in situ holds high clinical promise for lesion-specific elimination of primary, abscopal, and metastatic tumors, which may enlighten more bioinspired nanoplatforms for anticancer theranostics.