title: HAHAHA, HEHEHE, HIHIHI, or HKHKHK: influence of position and composition of histidine containing tags on biodistribution of [(99m)Tc(CO)3](+)-labeled affibody molecules.
abstract: Engineered affibody molecules can be used for high contrast in vivo molecular imaging. Extending a recombinantly produced HER2 binding affibody molecule with a hexa-histidine tag allows for convenient purification by immobilized metal-ion affinity chromatography and labeling with [(99m)Tc(CO)3](+) but increases radioactivity uptake in the liver. To investigate the impact of charge, lipophilicity, and position on biodistribution, 10 variants of a histidine-based tag was attached to a HER2 binding affibody molecule. The biochemical properties and the HER2 binding affinity appeared to be similar for all variants. In vivo, positive charge promoted liver uptake. For N-terminally placed tags, lipophilicity promoted liver uptake and decreased kidney uptake. Kidney uptake was higher for C-terminally placed tags compared to their N-terminal counterparts. The variant with the amino acid composition HEHEHE placed in the N-terminus gave the lowest nonspecific uptake.
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden.
authors.forename: Camilla
authors.initials: C
authors.lastname: Hofström
authors.forename: Mohamed
authors.initials: M
authors.lastname: Altai
authors.forename: Hadis
authors.initials: H
authors.lastname: Honarvar
authors.forename: Joanna
authors.initials: J
authors.lastname: Strand
authors.forename: Jennie
authors.initials: J
authors.lastname: Malmberg
authors.forename: Seyed Jalal
authors.initials: SJ
authors.lastname: Hosseinimehr
authors.forename: Anna
authors.initials: A
authors.lastname: Orlova
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Gräslund
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tolmachev
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004355:Drug Stability; D005260:Female; D006639:Histidine; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007553:Isotope Labeling; D007700:Kinetics; D051379:Mice; D015609:Organotechnetium Compounds / Q000737:chemistry*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics*; D014018:Tissue Distribution
chemical_list: D006639:Histidine; D015609:Organotechnetium Compounds; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins