Synthesis and evaluation of copper-64 labeled benzofuran derivatives targeting β-amyloid aggregates

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• 作者：Hiroyuki Watanabe ; Azusa Kawasaki ; Kohei Sano ; Masahiro Ono ; ^{ono@pharm.kyoto-u.ac.jp" class="auth_mail" title="E-mail the corresponding author} ; Hideo Saji
• 关键词：β-Amyloid ; Alzheimer&rsquo ; s disease ; PET ; Imaging ; Copper-64
• 刊名：Bioorganic & Medicinal Chemistry
• 出版年：2016
• 出版时间：15 August 2016
• 年：2016
• 卷：24
• 期：16
• 页码：3618-3623
• 全文大小：696 K

文摘

In vivo imaging of β-amyloid (Aβ) aggregates consisting of Aβ(1–40) and Aβ(1–42) peptides by positron emission tomography (PET) contributes to the diagnosis and therapy for Alzheimer’s disease (AD). Because ⁶⁴Cu (t_1/2 = 12.7 h) is a radionuclide for PET with a longer physical half-life than ¹¹C (t_1/2 = 20 min) and ¹⁸F (t_1/2 = 110 min), it is an attractive radionuclide for the development of Aβ imaging probes that are suitable for routine use. In the present study, we designed and synthesized two novel ⁶⁴Cu labeled benzofuran derivatives and evaluated their utility as PET imaging probes for Aβ aggregates. In an in vitro binding assay, 6 and 8 showed binding affinity for Aβ(1–42) aggregates with a K_i value of 33 and 243 nM, respectively. In addition, these probes bound to Aβ plaques deposited in the brain of an AD model mouse in vitro. In a biodistribution experiment using normal mice, these probes showed low brain uptake (0.33% and 0.36% ID/g) at 2 min post-injection. Although refinement to enhance brain uptake is needed, [⁶⁴Cu]6 and [⁶⁴Cu]8 demonstrated the feasibility of developing novel PET probes for imaging Aβ aggregates.