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Targeted photodynamic therapy with multiply‐loaded recombinant antibody fragments
Author(s) -
Bhatti Manpreet,
Yahioglu Gokhan,
Milgrom Lionel R.,
GarciaMaya Mitla,
Chester Kerry A.,
Deonarain Mahendra P.
Publication year - 2007
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.23206
Subject(s) - photodynamic therapy , photosensitizer , verteporfin , in vivo , cancer research , medicine , cancer , antibody , breast cancer , pharmacology , chemistry , immunology , biology , surgery , microbiology and biotechnology , organic chemistry , visual acuity , choroidal neovascularization
Current photodynamic therapy (PDT) of cancer is limited by inefficiencies involved in specifically targeting photosensitizers to tumors. Although antibodies are being explored as targeting vehicles, they present significant challenges, particularly in terms of pharmacokinetics and drug‐coupling. We describe here a novel and effective system to covalently attach multiple photosensitizer molecules (both preclinical, pyropheophorbide‐ a and clinically approved, verteporfin photosensitizers) to single‐chain Fvs. Further, we demonstrate that not only do the resulting photoimmunoconjugates retain photophysical functionality, they are more potent than either free photosensitizer, effectively killing tumor cells in vitro and in vivo . For example, treatment of human breast cancer xenografts with a photoimmunoconjugate comprising an anti‐HER‐2 scFv linked to 8–10 molecules of pyropheophorbide‐ a leads to significant tumor regression. These results give an insight into the important features that make scFvs good carriers for PDT drugs and provide proof of concept of our unique approach to targeted photodynamic therapy ( t PDT). This promises to significantly improve on current photodynamic therapies for the treatment of cancer. © 2007 Wiley‐Liss, Inc.