Enhanced binding and killing of target tumor cells by drug-loaded liposomes modified with tumor-specific phage fusion coat protein.
OBJECTIVE
To explore cancer cell-specific phage fusion pVIII coat protein, identified using phage display, for targeted delivery of drug-loaded liposomes to MCF-7 breast cancer cells.


METHODS
An 8-mer landscape library f8/8 and a biopanning protocol against MCF-7 cells were used to select a landscape phage protein bearing MCF-7-specific peptide. Size and morphology of doxorubicin-loaded liposomes modified with the tumor-specific phage fusion coat protein (phage-Doxil) were determined by dynamic light scattering and freeze-fraction electron microscopy. Topology of the phage protein in liposomes was examined by western blot. Association of phage-Doxil with MCF-7 cells was evaluated by fluorescence microscopy and fluorescence spectrometry. Selective targeting to MCF-7 was shown by FACS using a coculture model with target and nontarget cells. Phage-Doxil-induced tumor cell killing and apoptosis were confirmed by CellTiter-Blue Assay and caspase-3/CPP32 fluorometric assay.


RESULTS
A chimeric phage fusion coat protein specific towards MCF-7 cells, identified from a phage landscape library, was directly incorporated into the liposomal bilayer of doxorubicin-loaded PEGylated liposomes (Doxil) without additional conjugation with lipophilic moieties. Western blotting confirmed the presence of both targeting peptide and pVIII coat protein in the phage-Doxil, which maintained the liposomal morphology and retained a substantial part of the incorporated drug after phage protein incorporation. The binding activity of the phage fusion pVIII coat protein was retained after incorporation into liposomes, and phage-Doxil strongly and specifically targeted MCF-7 cells, demonstrating significantly increased cytotoxicity towards target cells in vitro.


CONCLUSIONS
We present a novel and straightforward method for making tumor-targeted nanomedicines by anchoring specific phage proteins (substitute antibodies) on their surface.
Wang
Tao
T
Department of Pharmaceutical Sciences & Center for Pharmaceutical Biotechnology & Nanomedicine, Northeastern University, Boston, MA 02115, USA.
D'Souza
Gerard G M
GG
Bedi
Deepa
D
Fagbohun
Olusegun A
OA
Potturi
L Prasanna
LP
Papahadjopoulos-Sternberg
Brigitte
B
Petrenko
Valery A
VA
Torchilin
Vladimir P
VP
D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D001435:Bacteriophages / Q000737:chemistry*; D015153:Blotting, Western; D036022:Capsid Proteins / Q000737:chemistry*; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000008:administration & dosage*; D004337:Drug Carriers; D005614:Freeze Fracturing; D006801:Humans; D008081:Liposomes; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000473:pathology*
D000970:Antineoplastic Agents; D036022:Capsid Proteins; D004337:Drug Carriers; D008081:Liposomes; D004317:Doxorubicin