{"entity": "publication", "iuid": "e4e9d94ba60d4c2399b5b7e2d7d151e3", "timestamp": "2026-08-22T08:30:21.530Z", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/e4e9d94ba60d4c2399b5b7e2d7d151e3.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/e4e9d94ba60d4c2399b5b7e2d7d151e3"}}, "title": "Optimal composition and position of histidine-containing tags improves biodistribution of 99mTc-labeled DARPin G3.", "authors": [{"family": "Vorobyeva", "given": "Anzhelika", "initials": "A", "orcid": "0000-0002-4778-3909", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/99703faa11ab4c19aff2f426f61c3134.json"}}, {"family": "Schulga", "given": "Alexey", "initials": "A"}, {"family": "Konovalova", "given": "Elena", "initials": "E"}, {"family": "G\u00fcler", "given": "Rezan", "initials": "R"}, {"family": "L\u00f6fblom", "given": "John", "initials": "J", "orcid": "0000-0001-9423-0541", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/bf8479d43c1c45efb85ba0c0da634aeb.json"}}, {"family": "Sandstr\u00f6m", "given": "Mattias", "initials": "M"}, {"family": "Garousi", "given": "Javad", "initials": "J"}, {"family": "Chernov", "given": "Vladimir", "initials": "V"}, {"family": "Bragina", "given": "Olga", "initials": "O"}, {"family": "Orlova", "given": "Anna", "initials": "A", "orcid": "0000-0001-6120-2683", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1c374f429702489494c05f84f298b4b7.json"}}, {"family": "Tolmachev", "given": "Vladimir", "initials": "V", "orcid": "0000-0002-6122-1734", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/896ae9fae8b74251afe11b4354c62794.json"}}, {"family": "Deyev", "given": "Sergey M", "initials": "SM"}], "type": "journal article", "published": "2019-06-28", "journal": {"title": "Sci Rep", "issn": "2045-2322", "volume": "9", "issue": "1", "pages": "9405", "issn-l": "2045-2322"}, "abstract": "Radionuclide molecular imaging of HER2 expression in disseminated cancer enables stratification of patients for HER2-targeted therapies. DARPin G3, a small (14 kDa) engineered scaffold protein, is a promising probe for imaging of HER2. We hypothesized that position (C- or N-terminus) and composition (hexahistidine or (HE)3) of histidine-containing tags would influence the biodistribution of [99mTc]Tc(CO)3-labeled DARPin G3. To test the hypothesis, G3 variants containing tags at N-terminus (H6-G3 and (HE)3-G3) or at C-terminus (G3-H6 and G3-(HE)3) were labeled with [99mTc]Tc(CO)3. Labeling yield, label stability, specificity and affinity of the binding to HER2, biodistribution and tumor targeting properties of these variants were compared side-by-side. There was no substantial influence of position and composition of the tags on binding of [99mTc]Tc(CO)3-labeled variants to HER2. The specificity of HER2 targeting in vivo was confirmed. The tumor uptake in BALB/c nu/nu mice bearing SKOV3 xenografts was similar for all variants. On the opposite, there was a strong influence of the tags on uptake in normal tissues. The tumor-to-liver ratio for [99mTc]Tc(CO)3-(HE)3-G3 was three-fold higher compared to the hexahistidine-tag containing variants. Overall, [99mTc]Tc(CO)3-(HE)3-G3 variant provided the highest tumor-to-lung, tumor-to-liver, tumor-to-bone and tumor-to-muscle ratios, which should improve sensitivity of HER2 imaging in these common metastatic sites.", "doi": "10.1038/s41598-019-45795-8", "pmid": "31253840", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC6599047"}, {"db": "pii", "key": "10.1038/s41598-019-45795-8"}], "notes": [], "created": "2026-08-21T11:52:49.253Z", "modified": "2026-08-21T11:52:49.317Z"}