title: Bispecific single-chain diabody-immunoliposomes targeting endoglin (CD105) and fibroblast activation protein (FAP) simultaneously.
abstract: Liposomes are well-established drug delivery systems with cancer chemotherapy as main focus. To increase the cellular drug delivery, liposomes can be endowed with ligands, e.g. recombinant antibody fragments, which ensure specific cell interaction. Multispecific immunoliposomes can be prepared to improve the liposome to cell interaction by targeting multiple different targets at the same time, for instance by coupling two or more different ligands to the liposomal surface, resulting in a synergistic or additive increase in binding. An alternative approach is the use of bispecific ligands to address at least two different targets. For this purpose we cloned a single-chain diabody fragment (scDb`), a bispecific molecule targeting two antigens, endoglin (CD105) and fibroblast activation protein (FAP), expressed on cells of the tumor microenvironment. As model cell system, a human fibrosarcoma cell line was used expressing endoglin and FAP simultaneously. Monospecific immunoliposomes directed either against endoglin or FAP were compared in vitro for cell binding and cytotoxic activity with bispecific dual-targeted scFv`-IL (bispecific scFv`FAP/CD105-IL) and bispecific single-chain diabody`-IL (scDb`CD105/FAP-IL) targeting endoglin and FAP simultaneously. In the underlying study, bispecific scFv`FAP/CD105-IL interacted stronger with cells expressing FAP and endoglin (both targets simultaneously) compared to the monospecific immunoliposomes. Furthermore, bispecific scDb`-immunoliposomes increased the cell interaction massively and showed enhanced cytotoxicity against target cells using doxorubicin-loaded immunoliposomes. The use of recombinant bispecific ligands as scDb`-molecules facilitates the generation of bispecific immunoliposomes by using the established post-insertion technique, enabling an extension of the ligand specificity spectrum via genetic modification.
authors.affiliation: Department of Pharmaceutical Technology, Friedrich-Schiller-University Jena, Lessingstrasse 8, 07743 Jena, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Rabenhold
authors.affiliation: Center for Electron microscopy, Jena University Hospital - Friedrich Schiller University Jena, Ziegelmuehlenweg 1, 07743 Jena, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Steiniger
authors.affiliation: Department of Pharmaceutical Technology, Friedrich-Schiller-University Jena, Lessingstrasse 8, 07743 Jena, Germany.
authors.forename: Alfred
authors.initials: A
authors.lastname: Fahr
authors.affiliation: Institute of Cell Biology and Immunology, University Stuttgart, Allmandring 31, 70569 Stuttgart, Germany.
authors.forename: Roland E
authors.initials: RE
authors.lastname: Kontermann
authors.affiliation: Department of Pharmaceutical Technology, Friedrich-Schiller-University Jena, Lessingstrasse 8, 07743 Jena, Germany. Electronic address: ronny.rueger@uni-jena.de.
authors.forename: Ronny
authors.initials: R
authors.lastname: Rüger
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage; D018033:Antibodies, Bispecific / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004317:Doxorubicin / Q000008:administration & dosage; D000071063:Endoglin; D010450:Endopeptidases; D018093:Gelatinases / Q000276:immunology*; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D008081:Liposomes; D008565:Membrane Proteins / Q000276:immunology*; D051379:Mice; D011956:Receptors, Cell Surface / Q000276:immunology*; D012697:Serine Endopeptidases / Q000276:immunology*; D057127:Single-Chain Antibodies / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D000099167:Fibroblast Activation Protein Alpha
chemical_list: D000903:Antibiotics, Antineoplastic; D018033:Antibodies, Bispecific; D015703:Antigens, CD; D004317:Doxorubicin; D000071063:Endoglin; D010450:Endopeptidases; D018093:Gelatinases; D008081:Liposomes; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D012697:Serine Endopeptidases; D057127:Single-Chain Antibodies; D000099167:Fibroblast Activation Protein Alpha; C064206:ENG protein, human
keywords: Endoglin; FAP; Immunoliposomes; Single-chain diabody; Targeting