title: EGFR targeted nanobody-photosensitizer conjugates for photodynamic therapy in a pre-clinical model of head and neck cancer.
abstract: Photodynamic therapy (PDT) induces cell death through local light activation of a photosensitizer (PS) and has been used to treat head and neck cancers. Yet, common PS lack tumor specificity, which leads to collateral damage to normal tissues. Targeted delivery of PS via antibodies has pre-clinically improved tumor selectivity. However, antibodies have long half-lives and relatively poor tissue penetration, which could limit therapeutic efficacy and lead to long photosensitivity. Here, in this feasibility study, we evaluate at the pre-clinical level a recently introduced format of targeted PDT, which employs nanobodies as targeting agents and a water-soluble PS (IRDye700DX) that is traceable through optical imaging. In vitro, the PS solely binds to cells and induces phototoxicity on cells overexpressing the epidermal growth factor receptor (EGFR), when conjugated to the EGFR targeted nanobodies. To investigate whether this new format of targeted PDT is capable of inducing selective tumor cell death in vivo, PDT was applied on an orthotopic mouse tumor model with illumination at 1h post-injection of the nanobody-PS conjugates, as selected from quantitative fluorescence spectroscopy measurements. In parallel, and as a reference, PDT was applied with an antibody-PS conjugate, with illumination performed 24h post-injection. Importantly, EGFR targeted nanobody-PS conjugates led to extensive tumor necrosis (approx. 90%) and almost no toxicity in healthy tissues, as observed through histology 24h after PDT. Overall, results show that these EGFR targeted nanobody-PS conjugates are selective and able to induce tumor cell death in vivo. Additional studies are now needed to assess the full potential of this approach to improving PDT.
authors.affiliation: Department of Radiology, Division of Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; Percuros BV, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
authors.forename: Pieter B A A
authors.initials: PBAA
authors.lastname: van Driel
authors.affiliation: Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Boonstra
authors.affiliation: Department of Radiology, Division of Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; Percuros BV, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
authors.forename: Maxime D
authors.initials: MD
authors.lastname: Slooter
authors.affiliation: Molecular Oncology, Cell Biology Division, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Raimond
authors.initials: R
authors.lastname: Heukers
authors.affiliation: Department of Radiology, Division of Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; Percuros BV, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
authors.forename: Marieke A
authors.initials: MA
authors.lastname: Stammes
authors.affiliation: Department of Radiology, Division of Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
authors.forename: Thomas J A
authors.initials: TJA
authors.lastname: Snoeks
authors.affiliation: Department of Otorhinolaryngology & Head and Neck Surgery, Center for Optical Diagnostics and Therapy, Erasmus Medical Center, s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: Henriette S
authors.initials: HS
authors.lastname: de Bruijn
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: van Diest
authors.affiliation: Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Vahrmeijer
authors.affiliation: Molecular Oncology, Cell Biology Division, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Paul M P
authors.initials: PMP
authors.lastname: van Bergen En Henegouwen
authors.affiliation: Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
authors.forename: Cornelis J H
authors.initials: CJH
authors.lastname: van de Velde
authors.affiliation: Department of Radiology, Division of Molecular Imaging, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
authors.forename: Clemens W G M
authors.initials: CWGM
authors.lastname: Löwik
authors.affiliation: Department of Otorhinolaryngology & Head and Neck Surgery, Center for Optical Diagnostics and Therapy, Erasmus Medical Center, s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: Dominic J
authors.initials: DJ
authors.lastname: Robinson
authors.affiliation: Molecular Oncology, Cell Biology Division, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. Electronic address: s.oliveira@uu.nl.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Oliveira
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D018920:Coculture Techniques; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D007211:Indoles / Q000008:administration & dosage* / Q000627:therapeutic use; D008027:Light; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D017646:Organosilicon Compounds / Q000008:administration & dosage* / Q000627:therapeutic use; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D061905:Single-Domain Antibodies / Q000008:administration & dosage* / Q000627:therapeutic use; D014062:Tongue Neoplasms / Q000188:drug therapy* / Q000378:metabolism
chemical_list: C000623382:IRDye700DX N-hydroxysuccinimide ester; D007211:Indoles; D017646:Organosilicon Compounds; D017319:Photosensitizing Agents; D061905:Single-Domain Antibodies; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: EGFR; Head and neck cancer; Nanobody or VHH; Photodynamic therapy; Quantitative fluorescence spectroscopy; Tumor targeting