We have tailored multifaceted chemistries into the manufacture of artificial virus-like delivery vehicles mimicking viral "intelligent" transportation pathways through sequential biological barriers; these vehicles can acquire the ability to dynamically "program transfer" to their target sites. To accomplish this, we created anionic pro-
proteins, which facilitate charge reversal when subject to acidic endosomal pH; in this way, carboxylation reactions are performed on
proteins with
amine-reactive cis-
aconitic anhydride. Electrostatic associations then initiate the envelopment of these pro-
proteins into multilayered nanoarchitectural vehicles composed of multiple-segmental block copolycationic cyclic
Arg-Gly-Asp (RGD)-poly(
ethylene glycol)(PEG)-GPLGVRG-
polylysine(
thiol). Therefore, upon the pro-
proteins' initial binding to the
tumors via the protruding RGD
ligands, the bio-inert PEG surroundings are detached through the enzymolysis of the intermediate GPLGVRG linkage by
tumor-enriched
matrix metalloproteinases, unveiling the cationic
polylysine palisade and imparting intimate affinities to the anionic cytomembranes of the targeted
tumors. Essentially, through their active endocytosis into the subcellular endosomal compartments, the pro-
proteins are made capable of retrieving the original
amine groups through a charge reversal decarboxylation process, consequently eliciting augmented charge densities (charge nonstoichiometric
protein@
polylysine(
disulfide)) to disrupt the anionic endosomal membranes to facilitate translocation into the cytosol. Eventually, the active
protein payloads can be liberated from nonstoichiometric
protein@
polylysine(
thiol) by the disassembly of
polylysine palisade upon the cleavage of
disulfide crosslinking in response to the very high level of
glutathione in the cytosol, thereby contributing toward extreme cytotoxic potency. Hence, our elaborated virus-mimicking platform has demonstrated potent antitumor efficacy through the systemic administration of
ribonucleases, which will consequently lead to an innovative new therapeutic method by which
proteins could reach intracellular targets.