title: Fluorescence characterisation of multiply-loaded anti-HER2 single chain Fv-photosensitizer conjugates suitable for photodynamic therapy.
abstract: We report the synthesis, spectroscopic properties and intracellular imaging of recombinant antibody single chain fragment (scFv) conjugates with photosensitizers used for photodynamic therapy of cancer (PDT). Two widely-studied photosensitizers have been selected: preclinical pyropheophorbide-a (PPa) and verteporfin (VP), which has been clinically approved for the treatment of acute macular degeneration (Visudyne). Pyropheophorbide-a and verteporfin have been conjugated to an anti-HER2 scFv containing on average ten photosensitizer molecules per scFv with a small contribution (<or=20%) from non-covalently bound molecules. Confocal fluorescence microscopy demonstrates good cellular uptake of PPa conjugate with the HER2-positive cell line, SKOV-3, while negligible cell uptake is demonstrated for the HER2-negative cell line, KB. For the VP conjugate, increased rate of cellular uptake and prolonged retention in SKOV-3 cells is observed compared to free photosensitizer. In clinical applications this could provide increased potency and desired selectivity towards malignant tissue, leaving surrounding healthy tissue unharmed and reducing skin photosensitivity. The present study highlights the usefulness of photosensitizer immunoconjugates with scFvs for targeted PDT.
authors.affiliation: Chemistry Department, Imperial College London, Exhibition Road, UK.
authors.forename: Marina K
authors.initials: MK
authors.lastname: Kuimova
authors.forename: Manpreet
authors.initials: M
authors.lastname: Bhatti
authors.forename: Mahendra
authors.initials: M
authors.lastname: Deonarain
authors.forename: Gokhan
authors.initials: G
authors.lastname: Yahioglu
authors.forename: James A
authors.initials: JA
authors.lastname: Levitt
authors.forename: Ioanna
authors.initials: I
authors.lastname: Stamati
authors.forename: Klaus
authors.initials: K
authors.lastname: Suhling
authors.forename: David
authors.initials: D
authors.lastname: Phillips
mesh_terms: D045744:Cell Line, Tumor; D005453:Fluorescence; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000276:immunology* / Q000494:pharmacology / Q000627:therapeutic use; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D007135:Immunoglobulin Variable Region; D017319:Photosensitizing Agents; D018719:Erb-b2 Receptor Tyrosine Kinases