{"entity": "researcher", "timestamp": "2026-08-22T07:48:34.613Z", "family": "Schulga", "given": "Alexey", "initials": "A", "orcid": "0000-0003-3425-0828", "affiliations": ["Research Centrum for Oncotheranostics, Research School of Chemistry and Applied Biomedical Sciences, Tomsk Polytechnic University, 634050 Tomsk, Russia.", "Molecular Immunology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia."], "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7"}}, "publications": [{"entity": "publication", "iuid": "4141afd0a66b44d183c7467bdf4893e1", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/4141afd0a66b44d183c7467bdf4893e1.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/4141afd0a66b44d183c7467bdf4893e1"}}, "title": "Feasibility of Co-Targeting HER3 and EpCAM Using Seribantumab and DARPin-Toxin Fusion in a Pancreatic Cancer Xenograft Model.", "authors": [{"family": "Xu", "given": "Tianqi", "initials": "T", "orcid": "0000-0002-1826-4093", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/688f685bf3474e72bfab58e1fa2035b9.json"}}, {"family": "Schulga", "given": "Alexey", "initials": "A", "orcid": "0000-0003-3425-0828", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7.json"}}, {"family": "Konovalova", "given": "Elena", "initials": "E"}, {"family": "Rinne", "given": "Sara S", "initials": "SS", "orcid": "0000-0003-2141-3982", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/3aea3edd98b441c98bb527b1e0c911f5.json"}}, {"family": "Zhang", "given": "Hongchao", "initials": "H"}, {"family": "Vorontsova", "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": "Deyev", "given": "Sergey M", "initials": "SM", "orcid": "0000-0002-3952-0631", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/fb88df2aaa8a46a5957370b9258e2834.json"}}, {"family": "Tolmachev", "given": "Vladimir", "initials": "V", "orcid": "0000-0002-6122-1734", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/896ae9fae8b74251afe11b4354c62794.json"}}, {"family": "Vorobyeva", "given": "Anzhelika", "initials": "A", "orcid": "0000-0002-4778-3909", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/99703faa11ab4c19aff2f426f61c3134.json"}}], "type": "journal article", "published": "2023-02-02", "journal": {"title": "Int J Mol Sci", "issn": "1422-0067", "volume": "24", "issue": "3", "issn-l": null}, "abstract": "Pancreatic cancer (PC) is one of the most aggressive malignancies. A combination of targeted therapies could increase the therapeutic efficacy in tumors with heterogeneous target expression. Overexpression of the human epidermal growth factor receptor type 3 (HER3) and the epithelial cell adhesion molecule (EpCAM) in up to 40% and 30% of PCs, respectively, is associated with poor prognosis and highlights the relevance of these targets. Designed ankyrin repeat protein (DARPin) Ec1 fused with the low immunogenic bacterial toxin LoPE provides specific and potent cytotoxicity against EpCAM-expressing cancer cells. Here, we investigated whether the co-targeting of HER3 using the monoclonal antibody seribantumab (MM-121) and of EpCAM using Ec1-LoPE would improve the therapeutic efficacy in comparison to the individual agents. Radiolabeled 99mTc(CO)3-Ec1-LoPE showed specific binding with rapid internalization in EpCAM-expressing PC cells. MM-121 did not interfere with the binding of Ec1-LoPE to EpCAM. Evaluation of cytotoxicity indicated synergism between Ec1-LoPE and MM-121 in vitro. An experimental therapy study using Ec1-LoPE and MM-121 in mice bearing EpCAM- and HER3-expressing BxPC3 xenografts demonstrated the feasibility of the therapy. Further development of the co-targeting approach using HER3 and EpCAM could therefore be justified.", "doi": "10.3390/ijms24032838", "pmid": "36769161", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC9917732"}, {"db": "pii", "key": "ijms24032838"}], "notes": [], "created": "2026-08-21T13:03:41.482Z", "modified": "2026-08-21T13:03:41.558Z"}, {"entity": "publication", "iuid": "fe07ae0a7fad420aad6593affa247d96", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/fe07ae0a7fad420aad6593affa247d96.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/fe07ae0a7fad420aad6593affa247d96"}}, "title": "Imaging-Guided Therapy Simultaneously Targeting HER2 and EpCAM with Trastuzumab and EpCAM-Directed Toxin Provides Additive Effect in Ovarian Cancer Model.", "authors": [{"family": "Xu", "given": "Tianqi", "initials": "T", "orcid": "0000-0002-1826-4093", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/688f685bf3474e72bfab58e1fa2035b9.json"}}, {"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", "orcid": "0000-0003-3425-0828", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7.json"}}, {"family": "Konovalova", "given": "Elena", "initials": "E"}, {"family": "Vorontsova", "given": "Olga", "initials": "O"}, {"family": "Ding", "given": "Haozhong", "initials": "H", "orcid": "0000-0003-1093-8222", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/3ee6fb5a9b694c1d8a40cc41e9d16146.json"}}, {"family": "Gr\u00e4slund", "given": "Torbj\u00f6rn", "initials": "T", "orcid": "0000-0002-5391-600X", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/afff2431691348539334ab0e86158505.json"}}, {"family": "Tashireva", "given": "Liubov A", "initials": "LA", "orcid": "0000-0003-2061-8417", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/e462c38bfd8846588156097b5602341a.json"}}, {"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", "orcid": "0000-0002-3952-0631", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/fb88df2aaa8a46a5957370b9258e2834.json"}}], "type": "journal article", "published": "2021-08-04", "journal": {"title": "Cancers (Basel)", "issn": "2072-6694", "volume": "13", "issue": "16", "issn-l": "2072-6694"}, "abstract": "Efficient treatment of disseminated ovarian cancer (OC) is challenging due to its heterogeneity and chemoresistance. Overexpression of human epidermal growth factor receptor 2 (HER2) and epithelial cell adhesion molecule (EpCAM) in approx. 30% and 70% of ovarian cancers, respectively, allows for co-targeted treatment. The clinical efficacy of the monoclonal antibody trastuzumab in patients with HER2-positive breast, gastric and gastroesophageal cancers makes it readily available as the HER2-targeting component. As the EpCAM-targeting component, we investigated the designed ankyrin repeat protein (DARPin) Ec1 fused to a truncated variant of Pseudomonas exotoxin A with reduced immunogenicity and low general toxicity (LoPE). Ec1-LoPE was radiolabeled, evaluated in ovarian cancer cells in vitro and its biodistribution and tumor-targeting properties were studied in vivo. The therapeutic efficacy of Ec1-LoPE alone and in combination with trastuzumab was studied in mice bearing EpCAM- and HER2-expressing SKOV3 xenografts. SPECT/CT imaging enabled visualization of EpCAM and HER2 expression in the tumors. Co-treatment using Ec1-LoPE and trastuzumab was more effective at reducing tumor growth and prolonged the median survival of mice compared with mice in the control and monotherapy groups. Repeated administration of Ec1-LoPE was well tolerated without signs of hepatic or kidney toxicity. Co-treatment with trastuzumab and Ec1-LoPE might be a potential therapeutic strategy for HER2- and EpCAM-positive OC.", "doi": "10.3390/cancers13163939", "pmid": "34439094", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC8393281"}, {"db": "pii", "key": "cancers13163939"}], "notes": [], "created": "2026-08-21T13:01:44.880Z", "modified": "2026-08-21T13:01:45.042Z"}, {"entity": "publication", "iuid": "f34c53feced64382a61689e6e503325f", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/f34c53feced64382a61689e6e503325f.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/f34c53feced64382a61689e6e503325f"}}, "title": "Influence of the Position and Composition of Radiometals and Radioiodine Labels on Imaging of Epcam Expression in Prostate Cancer Model Using the DARPin Ec1.", "authors": [{"family": "Deyev", "given": "Sergey M", "initials": "SM", "orcid": "0000-0002-3952-0631", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/fb88df2aaa8a46a5957370b9258e2834.json"}}, {"family": "Xu", "given": "Tianqi", "initials": "T", "orcid": "0000-0002-1826-4093", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/688f685bf3474e72bfab58e1fa2035b9.json"}}, {"family": "Liu", "given": "Yongsheng", "initials": "Y", "orcid": "0000-0001-5871-5779", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/a53363bbcb5b414681ee46ac22b65230.json"}}, {"family": "Schulga", "given": "Alexey", "initials": "A", "orcid": "0000-0003-3425-0828", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7.json"}}, {"family": "Konovalova", "given": "Elena", "initials": "E"}, {"family": "Garousi", "given": "Javad", "initials": "J"}, {"family": "Rinne", "given": "Sara S", "initials": "SS", "orcid": "0000-0003-2141-3982", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/3aea3edd98b441c98bb527b1e0c911f5.json"}}, {"family": "Larkina", "given": "Maria", "initials": "M", "orcid": "0000-0003-1176-2441", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/557c8a9c8b2142a7a88d6211335d24e4.json"}}, {"family": "Ding", "given": "Haozhong", "initials": "H", "orcid": "0000-0003-1093-8222", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/3ee6fb5a9b694c1d8a40cc41e9d16146.json"}}, {"family": "Gr\u00e4slund", "given": "Torbj\u00f6rn", "initials": "T", "orcid": "0000-0002-5391-600X", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/afff2431691348539334ab0e86158505.json"}}, {"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": "Vorobyeva", "given": "Anzhelika", "initials": "A", "orcid": "0000-0002-4778-3909", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/99703faa11ab4c19aff2f426f61c3134.json"}}], "type": "journal article", "published": "2021-07-17", "journal": {"title": "Cancers (Basel)", "issn": "2072-6694", "volume": "13", "issue": "14", "issn-l": "2072-6694"}, "abstract": "The epithelial cell adhesion molecule (EpCAM) is intensively overexpressed in 40-60% of prostate cancer (PCa) cases and can be used as a target for the delivery of drugs and toxins. The designed ankyrin repeat protein (DARPin) Ec1 has a high affinity to EpCAM (68 pM) and a small size (18 kDa). Radiolabeled Ec1 might be used as a companion diagnostic for the selection of PCa patients for therapy. The study aimed to investigate the influence of radiolabel position (N- or C-terminal) and composition on the targeting and imaging properties of Ec1. Two variants, having an N- or C-terminal cysteine, were produced, site-specifically conjugated to a DOTA chelator and labeled with cobalt-57, gallium-68 or indium-111. Site-specific radioiodination was performed using ((4-hydroxyphenyl)-ethyl)maleimide (HPEM). Biodistribution of eight radiolabeled Ec1-probes was measured in nude mice bearing PCa DU145 xenografts. In all cases, positioning of a label at the C-terminus provided the best tumor-to-organ ratios. The non-residualizing [125I]I-HPEM label provided the highest tumor-to-muscle and tumor-to-bone ratios and is more suitable for EpCAM imaging in early-stage PCa. Among the radiometals, indium-111 provided the highest tumor-to-blood, tumor-to-lung and tumor-to-liver ratios and could be used at late-stage PCa. In conclusion, label position and composition are important for the DARPin Ec1.", "doi": "10.3390/cancers13143589", "pmid": "34298801", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC8304184"}, {"db": "pii", "key": "cancers13143589"}], "notes": [], "created": "2026-08-21T13:01:42.532Z", "modified": "2026-08-21T13:01:42.881Z"}, {"entity": "publication", "iuid": "ab67eb7a966e4796b3cb5750aa00c79b", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/ab67eb7a966e4796b3cb5750aa00c79b.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/ab67eb7a966e4796b3cb5750aa00c79b"}}, "title": "Radionuclide Molecular Imaging of EpCAM Expression in Triple-Negative Breast Cancer Using the Scaffold Protein DARPin Ec1.", "authors": [{"family": "Vorobyeva", "given": "Anzhelika", "initials": "A", "orcid": "0000-0002-4778-3909", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/99703faa11ab4c19aff2f426f61c3134.json"}}, {"family": "Bezverkhniaia", "given": "Ekaterina", "initials": "E", "orcid": "0000-0001-7699-5719", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/211d24252bc84d43aed1d7ed4c3d3238.json"}}, {"family": "Konovalova", "given": "Elena", "initials": "E"}, {"family": "Schulga", "given": "Alexey", "initials": "A", "orcid": "0000-0003-3425-0828", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7.json"}}, {"family": "Garousi", "given": "Javad", "initials": "J", "orcid": "0000-0002-7224-6304", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/e103143bca5f4a5791c496ed36351132.json"}}, {"family": "Vorontsova", "given": "Olga", "initials": "O"}, {"family": "Abouzayed", "given": "Ayman", "initials": "A"}, {"family": "Orlova", "given": "Anna", "initials": "A", "orcid": "0000-0001-6120-2683", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1c374f429702489494c05f84f298b4b7.json"}}, {"family": "Deyev", "given": "Sergey", "initials": "S", "orcid": "0000-0002-3952-0631", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/fb88df2aaa8a46a5957370b9258e2834.json"}}, {"family": "Tolmachev", "given": "Vladimir", "initials": "V", "orcid": "0000-0002-6122-1734", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/896ae9fae8b74251afe11b4354c62794.json"}}], "type": "journal article", "published": "2020-10-14", "journal": {"title": "Molecules", "issn": "1420-3049", "volume": "25", "issue": "20", "issn-l": "1420-3049"}, "abstract": "Efficient treatment of disseminated triple-negative breast cancer (TNBC) remains an unmet clinical need. The epithelial cell adhesion molecule (EpCAM) is often overexpressed on the surface of TNBC cells, which makes EpCAM a potential therapeutic target. Radionuclide molecular imaging of EpCAM expression might permit selection of patients for EpCAM-targeting therapies. In this study, we evaluated a scaffold protein, designed ankyrin repeat protein (DARPin) Ec1, for imaging of EpCAM in TNBC. DARPin Ec1 was labeled with a non-residualizing [125I]I-para-iodobenzoate (PIB) label and a residualizing [99mTc]Tc(CO)3 label. Both imaging probes retained high binding specificity and affinity to EpCAM-expressing MDA-MB-468 TNBC cells after labeling. Internalization studies showed that Ec1 was retained on the surface of MDA-MB-468 cells to a high degree up to 24 h. Biodistribution in Balb/c nu/nu mice bearing MDA-MB-468 xenografts demonstrated specific uptake of both [125I]I-PIB-Ec1 and [99mTc]Tc(CO)3-Ec1 in TNBC tumors. [125I]I-PIB-Ec1 had appreciably lower uptake in normal organs compared with [99mTc]Tc(CO)3-Ec1, which resulted in significantly (p < 0.05) higher tumor-to-organ ratios. The biodistribution data were confirmed by micro-Single-Photon Emission Computed Tomography/Computed Tomography (microSPECT/CT) imaging. In conclusion, an indirectly radioiodinated Ec1 is the preferable probe for imaging of EpCAM in TNBC.", "doi": "10.3390/molecules25204719", "pmid": "33066684", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC7587533"}, {"db": "pii", "key": "molecules25204719"}], "notes": [], "created": "2026-08-21T13:04:24.418Z", "modified": "2026-08-21T13:04:24.508Z"}, {"entity": "publication", "iuid": "05b37e02f1c34796981e86fefcfaf18b", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/05b37e02f1c34796981e86fefcfaf18b.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/05b37e02f1c34796981e86fefcfaf18b"}}, "title": "Feasibility of Imaging EpCAM Expression in Ovarian Cancer Using Radiolabeled DARPin Ec1.", "authors": [{"family": "Vorobyeva", "given": "Anzhelika", "initials": "A", "orcid": "0000-0002-4778-3909", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/99703faa11ab4c19aff2f426f61c3134.json"}}, {"family": "Konovalova", "given": "Elena", "initials": "E"}, {"family": "Xu", "given": "Tianqi", "initials": "T", "orcid": "0000-0002-1826-4093", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/688f685bf3474e72bfab58e1fa2035b9.json"}}, {"family": "Schulga", "given": "Alexey", "initials": "A", "orcid": "0000-0003-3425-0828", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7.json"}}, {"family": "Altai", "given": "Mohamed", "initials": "M"}, {"family": "Garousi", "given": "Javad", "initials": "J", "orcid": "0000-0002-7224-6304", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/e103143bca5f4a5791c496ed36351132.json"}}, {"family": "Rinne", "given": "Sara S", "initials": "SS"}, {"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", "initials": "S"}], "type": "journal article", "published": "2020-05-07", "journal": {"title": "Int J Mol Sci", "issn": "1422-0067", "volume": "21", "issue": "9", "issn-l": null}, "abstract": "Epithelial cell adhesion molecule (EpCAM) is overexpressed in 55%-75% of ovarian carcinomas (OC). EpCAM might be used as a target for a treatment of disseminated OC. Designed ankyrin repeats protein (DARPin) Ec1 is a small (18 kDa) protein, which binds to EpCAM with subnanomolar affinity. We tested a hypothesis that Ec1 labeled with a non-residualizing label might serve as a companion imaging diagnostic for stratification of patients for EpCAM-targeting therapy. Ec1 was labeled with 125I using N-succinimidyl-para-iodobenzoate. Binding affinity, specificity, and cellular processing of [125I]I-PIB-Ec1 were evaluated using SKOV-3 and OVCAR-3 ovarian carcinoma cell lines. Biodistribution and tumor-targeting properties of [125I]I-PIB-Ec1 were studied in Balb/c nu/nu mice bearing SKOV-3 and OVCAR-3 xenografts. EpCAM-negative Ramos lymphoma xenografts served as specificity control. Binding of [125I]I-PIB-Ec1 to ovarian carcinoma cell lines was highly specific and had affinity in picomolar range. Slow internalization of [125I]I-PIB-Ec1 by OC cells confirmed utility of non-residualizing label for in vivo imaging. [125I]I-PIB-Ec1 provided 6 h after injection tumor-to-blood ratios of 30 \u00b1 11 and 48 \u00b1 12 for OVCAR-3 and SKOV-3 xenografts, respectively, and high contrast to other organs. Tumor targeting was highly specific. Saturation of tumor uptake at a high dose of Ec1 in SKOV-3 model provided a rationale for dose selection in further studies using therapeutic conjugates of Ec1 for targeted therapy. In conclusion, [125I]I-PIB-Ec1 is a promising agent for visualizing EpCAM expression in OC.", "doi": "10.3390/ijms21093310", "pmid": "32392820", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC7246691"}, {"db": "pii", "key": "ijms21093310"}], "notes": [], "created": "2026-08-21T13:03:11.331Z", "modified": "2026-08-21T13:03:11.449Z"}, {"entity": "publication", "iuid": "36e96cbc86d24943a69ab50c2cc0fee3", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/36e96cbc86d24943a69ab50c2cc0fee3.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/36e96cbc86d24943a69ab50c2cc0fee3"}}, "title": "Indirect Radioiodination of DARPin G3 Using N-succinimidyl-Para-Iodobenzoate Improves the Contrast of HER2 Molecular Imaging.", "authors": [{"family": "Vorobyeva", "given": "Anzhelika", "initials": "A"}, {"family": "Schulga", "given": "Alexey", "initials": "A", "orcid": "0000-0003-3425-0828", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/45b1c8e5447c41bbb93e61706377a0c7.json"}}, {"family": "Rinne", "given": "Sara S", "initials": "SS"}, {"family": "G\u00fcnther", "given": "Tyran", "initials": "T"}, {"family": "Orlova", "given": "Anna", "initials": "A", "orcid": "0000-0001-6120-2683", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1c374f429702489494c05f84f298b4b7.json"}}, {"family": "Deyev", "given": "Sergey", "initials": "S"}, {"family": "Tolmachev", "given": "Vladimir", "initials": "V", "orcid": "0000-0002-6122-1734", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/896ae9fae8b74251afe11b4354c62794.json"}}], "type": "journal article", "published": "2019-06-21", "journal": {"title": "Int J Mol Sci", "issn": "1422-0067", "volume": "20", "issue": "12", "issn-l": null}, "abstract": "Radionuclide molecular imaging of human epidermal growth factor receptor 2 (HER2) in breast and gastroesophageal cancer might be used to stratify patients for HER2-targeted therapy as well as monitor treatment response and disease progression. Designed ankyrin repeat proteins (DARPins) are small engineered scaffold proteins with favorable properties for molecular imaging. Herein we compared two methods for labeling the anti-HER2 DARPin (HE)3-G3, direct and indirect radioiodination. We hypothesized that the use of N-succinimidyl-para-iodobenzoate (SPIB) for radioiodination would facilitate the clearance of radiometabolites and improve the contrast of imaging. Both radiolabeled (HE)3-G3 variants preserved their binding specificity and high affinity to HER2-expressing cells. The specificity of tumor targeting in vivo was also demonstrated. A biodistribution comparison of [125I]I-(HE)3-G3 and [125I]I-PIB-(HE)3-G3, in mice bearing HER2 expressing SKOV3 xenografts, showed rapid clearance of [125I]I-PIB-(HE)3-G3 from normal organs and tissues and low accumulation of activity in organs with NaI-symporter expression. Both radiolabeled (HE)3-G3 variants had equal tumor uptake. Consequently, the indirect label provided higher tumor-to-blood and tumor-to-organ ratios compared with the direct label. Comparative Single Photon Emission Computed Tomography (SPECT)/CT imaging of HER2 expression in SKOV3 xenografts, using both radiolabeled DARPins, demonstrated the superior imaging contrast of the indirect label. Indirect radioiodination of (HE)3-G3 using SPIB could be further applied for SPECT and PET imaging with iodine-123 and iodine-124.", "doi": "10.3390/ijms20123047", "pmid": "31234471", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC6627094"}, {"db": "pii", "key": "ijms20123047"}], "notes": [], "created": "2026-08-21T13:02:59.588Z", "modified": "2026-08-21T13:02:59.646Z"}]}