title: F8-SIP mediated targeted photodynamic therapy leads to microvascular dysfunction and reduced glioma growth.
abstract: The extra domain A (ED A) of fibronectin has been identified as a tumor vessel specific neovascular marker in glioma. Antibody based vascular targeting against ED A of fibronectin allows precise accumulation of photosensitizer in glioma microvasculature and thereby promises to overcome drawbacks of current photodynamic therapy (PDT) for glioma treatment. Our aim was to characterize microcirculatory consequences of F8-small immunoprotein (SIP) mediated PDT by intravital microscopy (IVM) and to analyze the effects on glioma growth. For IVM SF126 glioma cells were implanted into dorsal skinfold-chamber of nude mice. PDT was performed after intravenous injection of photosensitizer (PS)-coupled F8-SIP or PBS (n = 4). IVM was performed before and after PDT for 4 days. Analysis included total and functional (TVD, FVD) vessel densities, perfusion index (PI), microvascular permeability and blood flow rate (Q). To assess tumor growth SF126 glioma cells were implanted subcutaneously. PDT was performed as a single and repetitive treatment after PS-F8-SIP injection (n = 5). Subcutaneous tumors were treated after uncoupled F8-SIP injection as control group (n = 5). PDT induced microvascular stasis and thrombosis with reduced FVD (24 h: 115.98 ± 0.7 vs. 200.8 ± 61.9 cm/cm(2)) and PI (39 ± 11 vs. 70 ± 10 %), whereas TVD was not altered (298 ± 39.2 vs. 278.2 ± 51 cm/cm(2)). Microvascular dysfunction recovered 4 days after treatment. Microvascular dysfunction led to a temporary reduction of glioma growth in the first 48 h after treatment with complete recovery 5 days after treatment. Repetitive PDT resulted in sustained reduction of tumor growth. F8-SIP mediated PDT leads to microvascular dysfunction and reduced glioma growth in a preclinical glioma model with recovery of microcirculation 4 days after treatment. Repetitive application of PDT overcomes microvascular recovery and leads to prolonged antiglioma effects.
authors.affiliation: Department of Neurosurgery, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Acker
authors.affiliation: Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH, Zurich, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Palumbo
authors.affiliation: Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH, Zurich, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Neri
authors.affiliation: Department of Neurosurgery, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany. peter.vajkoczy@charite.de.
authors.forename: P
authors.initials: P
authors.lastname: Vajkoczy
authors.affiliation: Department of Neurosurgery, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Czabanka
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000098:blood supply / Q000188:drug therapy*; D045744:Cell Line, Tumor; D005910:Glioma / Q000098:blood supply / Q000188:drug therapy*; D006801:Humans; D000069416:Intravital Microscopy; D008819:Mice, Nude; D055806:Microvessels / Q000187:drug effects*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D017319:Photosensitizing Agents
keywords: F8-SIP; Intravital microscopy; PDT; Vascular targeting