title: Protein nanocapsules containing doxorubicin as a pH-responsive delivery system.
abstract: The E2 component of pyruvate dehydrogenase is engineered to form a caged, hollow dodecahedral protein assembly, and the feasibility of this scaffold to be used as a drug delivery system is examined by introducing cysteines to the internal cavity (D381C). The fluorescent dye Alexa Fluor 532 (AF532M) and the antitumor drug doxorubicin are coupled to this internal cavity through maleimides on the guest molecules. The viruslike particle's structure and stability remain intact after binding of the molecules within the interior of the nanocapsule. The pH-dependent hydrolysis of a hydrazone linkage to doxorubicin allows 90% drug release from the D381C scaffold within 72 h at pH 5.0. Fluorescence microscopy of MDA-MB-231 breast cancer cells indicates significant uptake of the D381C scaffold incorporating AF532M and doxorubicin, and suggests internalization of the nanoparticles through endocytosis. It is observed that the protein scaffold does not induce cell death, but doxorubicin encapsulated in D381C is indeed cytotoxic, yielding an IC(50) of 1.3 ± 0.3 μM. While the majority of particulate-based drug delivery strategies encapsulates drugs within polymeric nanoparticles, these results show the potential for using macromolecular protein assemblies. This approach yields a promising new opportunity for designing highly defined nanomaterials for therapeutic delivery.
authors: Department of Chemical Engineering and Materials Science, University of California, 916 Engineering Tower, Irvine, CA 92697-2575, USA.
authors: Dongmei
authors: D
authors: Ren
authors: Felix
authors: F
authors: Kratz
authors: Szu-Wen
authors: SW
authors: Wang
mesh_terms: D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D051047:Dihydrolipoyllysine-Residue Acetyltransferase / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology*; D016503:Drug Delivery Systems; D004705:Endocytosis / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D018613:Microscopy, Confocal; D053769:Nanocapsules / Q000737:chemistry*; D055550:Protein Stability / Q000187:drug effects
chemical_list: D053769:Nanocapsules; D004317:Doxorubicin; D051047:Dihydrolipoyllysine-Residue Acetyltransferase