Feasibility of affibody-based bioorthogonal chemistry-mediated radionuclide pretargeting
2016 (English)In: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, no 3, 431-436 p.Article in journal (Refereed) Published
Affibody molecules constitute a new class of probes for radionuclide tumor targeting. The small size of affibody molecules is favorable for rapid localization in tumors and clearance from circulation. However, high renal re-absorption of affibody molecules prevents the use of residualizing radiometals, including a number of promising low energy beta- and alpha-emitters, for radionuclide therapy. We tested a hypothesis that affibody-based pretargeting mediated by a bioorthogonal interaction between trans-cyclooctene (TCO) and tetrazine would provide higher accumulation of radiometals in tumor xenografts than in the kidneys.
TCO was conjugated to the anti-HER2 affibody molecule Z2395. DOTA-tetrazine was labeled with indium-111 and lutetium-177. In vitro pretargeting was studied in HER2-expressing SKOV-3 and BT474 cell lines. In vivo studies were performed on BALB/C nu/nu mice bearing SKOV-3 xenografts.
125I-Z2395-TCO bound specifically to HER2-expressing cells in vitro with an affinity of 45±16 pM. 111In-tetrazine bound specifically and selectively to Z2395-TCO pre-treated cells. In vivo studies demonstrated HER2-specific 125I-Z2395-TCO accumulation in xenografts. TCO-mediated 111In-tetrazine localization was shown in tumors, when the radiolabeled tracer was injected 4 h after an injection of Z2395-TCO. At 1 h post injection, the tumor uptake of 111In-tetrazine and 177Lu-tetrazine was ca. 2-fold higher than the renal uptake. Pretargeting provided more than a 56-fold reduction of renal uptake of 111In in comparison with direct targeting.
The feasibility of affibody-based bioorthogonal chemistry-mediated pretargeting was demonstrated. The use of pretargeting provides a substantial reduction of radiometal accumulation in kidneys, creating preconditions for palliative radionuclide therapy.
Place, publisher, year, edition, pages
2016. Vol. 57, no 3, 431-436 p.
Clinical Medicine Radiology, Nuclear Medicine and Medical Imaging
IdentifiersURN: urn:nbn:se:uu:diva-273543DOI: 10.2967/jnumed.115.162248ISI: 000371371800037PubMedID: 26659353OAI: oai:DiVA.org:uu-273543DiVA: diva2:894793
FunderSwedish Cancer Society, 2012/354Swedish Research Council, 521-2012-2228Swedish Research Council, 621-2013-5135