Different radiolabelling methods alter the pharmacokinetic and biodistribution properties of Plasminogen Activator Inhibitor Type 2 (PAI-2) forms
dc.contributor.author | Ranson, M | en_AU |
dc.contributor.author | Berghofer, PJ | en_AU |
dc.contributor.author | Vine, KL | en_AU |
dc.contributor.author | Greguric, I | en_AU |
dc.contributor.author | Shepherd, R | en_AU |
dc.contributor.author | Katsifis, A | en_AU |
dc.date.accessioned | 2020-03-29T21:26:21Z | en_AU |
dc.date.available | 2020-03-29T21:26:21Z | en_AU |
dc.date.issued | 2012-08-01 | en_AU |
dc.date.statistics | 2020-03-20 | en_AU |
dc.description.abstract | Introduction Tumour-associated urokinase plasminogen activator (uPA) is a critical marker of invasion and metastasis, and it is recognised as having strong prognostic relevance as well as being a therapeutic target. The specific uPA inhibitor plasminogen activator inhibitor type-2 (PAI-2, SerpinB2) specifically targets cell bound uPA and is internalised. Furthermore, preclinical studies have established the “proof-of-principle” of uPA-targeting by PAI-2-cytotoxin conjugates in human carcinoma models. However, these studies also suggest that PAI-2 is rapidly cleared via the renal system with low total dose reaching the tumour. In this study, a comparative single photon emission computed tomography (SPECT) and biodistribution (BD) analysis of different forms of PAI-2 labelled with the radioisotopes iodine-123 (123I) and technetium-99m (99mTc) was undertaken. Methods The pharmacokinetic (PK) properties and BD of wild-type, ΔCD-loop and PEGylated ΔCD-loop PAI-2 labelled with the commonly used diagnostic SPECT radioisotopes 99mTc or 123I were compared in mouse models of human prostate carcinoma. Whole body SPECT imaging was also performed. Results Both wild-type and the shorter but active ΔCD-loop form of PAI-2 123I-labelled indirectly via conjugation to free amine groups (termed 123I-Bn-PAI-2) exhibited low tumour uptake, rapid excretion and similar PK profiles. Preliminary studies with a short branched-chain PEGylated 123I-Bn-PAI-2 ΔCD-loop indicated an increase in blood retention time and tumour uptake. All 123I-Bn-labelled radiotracers were largely excreted through the kidneys. By comparison, both wild-type 123I-PAI-2 (labelled directly via tyrosine residues) and 99mTc-PAI-2 displayed different PK/BD patterns compared to 123I-Bn-PAI-2, suggesting greater liver based catabolism and thus slower elimination. SPECT imaging mimicked the BD results of all radiotracers. © 2020 Elsevier B.V. Conclusion The different labelling methods gave distinct PAI-2 BD and tumour uptake profiles, with radioiodination resulting in the best non-tumour organ clearance profiles. Preliminary analyses with short branched-chain PEGylated 123I-Bn-PAI-2 ΔCD-loop suggest that further investigations with other PEGylation reagents are required to optimise this approach for tumour imaging. These findings impact on the use of PAI-2 for drug delivery and/or diagnostic development. © 2012 Published by Elsevier Inc. | en_AU |
dc.identifier.citation | Ranson, M., Berghofer, P., Vine, K. L., Greguric, I., Shepherd, R., & Katsifis, A. (2012). Different radiolabelling methods alter the pharmacokinetic and biodistribution properties of plasminogen activator inhibitor Type 2 (PAI-2) forms. Nuclear Medicine and Biology, 39(6), 833-839. doi:10.1016/j.nucmedbio.2012.01.006 | en_AU |
dc.identifier.govdoc | 8867 | en_AU |
dc.identifier.issn | 0969-8051 | en_AU |
dc.identifier.issue | 6 | en_AU |
dc.identifier.journaltitle | Nuclear Medicine and Biology | en_AU |
dc.identifier.pagination | 833-839 | en_AU |
dc.identifier.uri | https://doi.org/10.1016/j.nucmedbio.2012.01.006 | en_AU |
dc.identifier.uri | http://apo.ansto.gov.au/dspace/handle/10238/9288 | en_AU |
dc.identifier.volume | 39 | en_AU |
dc.language.iso | en | en_AU |
dc.publisher | Elsevier B.V. | en_AU |
dc.subject | Plasminogen | en_AU |
dc.subject | Enzyme inhibitors | en_AU |
dc.subject | Laboratory animals | en_AU |
dc.subject | Single photon emission computed tomography | en_AU |
dc.subject | Kinetics | en_AU |
dc.subject | Pharmacology | en_AU |
dc.subject | Technetium | en_AU |
dc.subject | Neoplasms | en_AU |
dc.subject | Tumor cells | en_AU |
dc.title | Different radiolabelling methods alter the pharmacokinetic and biodistribution properties of Plasminogen Activator Inhibitor Type 2 (PAI-2) forms | en_AU |
dc.type | Journal Article | en_AU |
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