Development of Radiogallium-Labeled Peptides for Platelet-Derived Growth Factor Receptor β (PDGFRβ) Imaging: Influence of Different Linkers

Autor: Nurmaya Effendi, Kenji Mishiro, Kazuhiro Shiba, Seigo Kinuya, Kazuma Ogawa
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Molecules, Vol 26, Iss 1, p 41 (2020)
Druh dokumentu: article
ISSN: 1420-3049
DOI: 10.3390/molecules26010041
Popis: The purpose of this study is to develop peptide-based platelet-derived growth factor receptor β (PDGFRβ) imaging probes and examine the effects of several linkers, namely un-natural amino acids (D-alanine and β-alanine) and ethylene-glycol (EG), on the properties of Ga-DOTA-(linker)-IPLPPPRRPFFK peptides. Seven radiotracers, 67Ga-DOTA-(linker)-IPLPPPRRPFFK peptides, were designed, synthesized, and evaluated. The stability and cell uptake in PDGFRβ positive peptide cells were evaluated in vitro. The biodistribution of [67Ga]Ga-DOTA-EG2-IPLPPPRRPFFK ([67Ga]27) and [67Ga]Ga-DOTA-EG4-IPLPPPRRPFFK ([67Ga]28), which were selected based on in vitro stability in murine plasma and cell uptake rates, were determined in BxPC3-luc-bearing nu/nu mice. Seven 67Ga-labeled peptides were successfully synthesized with high radiochemical yields (>85%) and purities (>99%). All evaluated radiotracers were stable in PBS (pH 7.4) at 37 °C. However, only [67Ga]27 and [67Ga]28 remained more than 75% after incubation in murine plasma at 37 °C for 1 h. [67Ga]27 exhibited the highest BxPC3-luc cell uptake among the prepared radiolabeled peptides. As regards the results of the biodistribution experiments, the tumor-to-blood ratios of [67Ga]27 and [67Ga]28 at 1 h post-injection were 2.61 ± 0.75 and 2.05 ± 0.77, respectively. Co-injection of [67Ga]27 and an excess amount of IPLPPPRRPFFK peptide as a blocking agent can significantly decrease this ratio. However, tumor accumulation was not considered sufficient. Therefore, further probe modification is required to assess tumor accumulation for in vivo imaging.
Databáze: Directory of Open Access Journals
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