{"entity": "publication", "iuid": "9b21fb72055b446c864df7a2b2775413", "timestamp": "2026-08-22T08:30:41.916Z", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/9b21fb72055b446c864df7a2b2775413.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/9b21fb72055b446c864df7a2b2775413"}}, "title": "Benefit of Later-Time-Point PET Imaging of HER3 Expression Using Optimized Radiocobalt-Labeled Affibody Molecules.", "authors": [{"family": "Rinne", "given": "Sara S", "initials": "SS"}, {"family": "Dahlsson Leitao", "given": "Charles", "initials": "C"}, {"family": "Saleh-Nihad", "given": "Zahra", "initials": "Z"}, {"family": "Mitran", "given": "Bogdan", "initials": "B"}, {"family": "Tolmachev", "given": "Vladimir", "initials": "V", "orcid": "0000-0002-6122-1734", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/896ae9fae8b74251afe11b4354c62794.json"}}, {"family": "St\u00e5hl", "given": "Stefan", "initials": "S"}, {"family": "L\u00f6fblom", "given": "John", "initials": "J", "orcid": "0000-0001-9423-0541", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/bf8479d43c1c45efb85ba0c0da634aeb.json"}}, {"family": "Orlova", "given": "Anna", "initials": "A", "orcid": "0000-0001-6120-2683", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1c374f429702489494c05f84f298b4b7.json"}}], "type": "journal article", "published": "2020-03-13", "journal": {"title": "Int J Mol Sci", "issn": "1422-0067", "volume": "21", "issue": "6", "issn-l": null}, "abstract": "HER3-binding affibody molecules are a promising format for visualization of HER3 expression. Cobalt-55, a positron-emitting isotope, with a half-life of 17.5 h, allows for next-day imaging. We investigated the influence of the charge of the radiocobalt-chelator complex on the biodistribution of anti-HER3 affibody molecule (HE)3-ZHER3 and compared the best radiocobalt-labeled variant with a recently optimized gallium-labeled variant. Affibody conjugates (HE)3-ZHER3-X (X = NOTA, NODAGA, DOTA, DOTAGA) were labeled with [57Co]Co (surrogate for 55Co). Affinity measurements, binding specificity and cellular processing were studied in two HER3-expressing cancer cell lines. Biodistribution was studied 3 and 24 h post-injection (pi) in mice with HER3-expressing BxPC-3 xenografts and compared to [68Ga]Ga-(HE)3-ZHER3-NODAGA. Micro-single-photon emission tomography/computed tomography (microSPECT/CT) and micro-positron emission tomography/computed tomography (microPET/CT) imaging was performed 3 and 24 h pi. Stably labeled conjugates bound to HER3 with subnanomolar affinity. [57Co]Co-(HE)3-ZHER3-DOTA had the best tumor retention and a significantly lower concentration in blood than other conjugates, leading to superior tumor-to-blood and tumor-to-liver ratios 24 h pi. Compared to [68Ga]Ga-(HE)3-ZHER3-NODAGA 3 h pi, [57Co]Co-(HE)3-ZHER3-DOTA provided superior imaging contrast in liver 24 h pi. Concluding, the composition and charge of the [57Co]Co-chelator complex influenced the uptake in tumors and normal tissue. [57Co]Co-(HE)3-ZHER3-DOTA provided the best imaging properties among the cobalt-labeled conjugates. Delayed imaging of HER3 expression with [57Co]Co-(HE)3-ZHER3-DOTA improved imaging contrast compared to early-time-point imaging with [68Ga]Ga-(HE)3-ZHER3-NODAGA.", "doi": "10.3390/ijms21061972", "pmid": "32183096", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC7139902"}, {"db": "pii", "key": "ijms21061972"}], "notes": [], "created": "2026-08-21T13:03:08.958Z", "modified": "2026-08-21T13:03:08.988Z"}