PURPOSE Human B7-H3 (hB7-H3) is a promising molecular imaging target differentially expressed on the neovasculature of breast cancer and has been validated for preclinical ultrasound (US) imaging with anti-B7-H3-antibody-functionalized microbubbles (MB). However, smaller ligands such as affibodies (ABY) are more suitable for the design of clinical-grade targeted MB. EXPERIMENTAL DESIGN Binding of ABYB7-H3 was confirmed with soluble and cell-surface B7-H3 by flow cytometry. MB were functionalized with ABYB7-H3 or anti-B7-H3-antibody (AbB7-H3). Control and targeted MB were tested for binding to hB7-H3-expressing cells (MS1hB7-H3) under shear stress conditions. US imaging was performed with MBABY-B7-H3 in an orthotopic mouse model of human MDA-MB-231 coimplanted with MS1hB7-H3 or control MS1WT cells and a transgenic mouse model of breast cancer development. RESULTS ABYB7-H3 specifically binds to MS1hB7-H3 and murine-B7-H3-expressing monocytes. MBABY-B7-H3 (8.5 ± 1.4 MB/cell) and MBAb-B7-H3 (9.8 ± 1.3 MB/cell) showed significantly higher (P < 0.0001) binding to the MS1hB7-H3 cells compared with control MBNon-targeted (0.5 ± 0.1 MB/cell) under shear stress conditions. In vivo, MBABY-B7-H3 produced significantly higher (P < 0.04) imaging signal in orthotopic tumors coengrafted with MS1hB7-H3 (8.4 ± 3.3 a.u.) compared with tumors with MS1WT cells (1.4 ± 1.0 a.u.). In the transgenic mouse tumors, MBABY-B7-H3 (9.6 ± 2.0 a.u.) produced higher (P < 0.0002) imaging signal compared with MBNon-targeted (1.3 ± 0.3 a.u.), whereas MBABY-B7-H3 signal in normal mammary glands and tumors with B7-H3 blocking significantly reduced (P < 0.02) imaging signal. CONCLUSIONS MBABY-B7-H3 enhances B7-H3 molecular signal in breast tumors, improving cancer detection, while offering the advantages of a small size ligand and easier production for clinical imaging.

中文翻译：

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基于亲和体的血管 B7-H3 超声分子成像对乳腺癌检测的功效。

目的人 B7-H3 (hB7-H3) 是一种在乳腺癌新生血管系统上差异表达的有前途的分子成像靶标，并且已通过抗 B7-H3 抗体功能化微泡 (MB) 的临床前超声 (US) 成像得到验证。然而，较小的配体如亲和体 (ABY) 更适合临床级靶向 MB 的设计。实验设计 ABYB7-H3 与可溶性和细胞表面 B7-H3 的结合通过流式细胞术确认。MB 用 ABYB7-H3 或抗 B7-H3 抗体 (AbB7-H3) 功能化。控制和目标 MB 在剪切应力条件下测试了与 hB7-H3 表达细胞 (MS1hB7-H3) 的结合。在与 MS1hB7-H3 或对照 MS1WT 细胞共同植入的人 MDA-MB-231 原位小鼠模型和乳腺癌发展的转基因小鼠模型中，使用 MBABY-B7-H3 进行美国成像。结果 ABYB7-H3 特异性结合 MS1hB7-H3 和表达鼠 B7-H3 的单核细胞。与对照 MB 非靶向 (0.5 ± 0.1 MB/细胞）在剪切应力条件下。在体内，与具有 MS1WT 细胞的肿瘤 (1.4 ± 1.0 au) 相比，MBABY-B7-H3 在与 MS1hB7-H3 (8.4 ± 3.3 au) 共同移植的原位肿瘤中产生显着更高 (P < 0.04) 的成像信号。在转基因小鼠肿瘤中，MBABY-B7-H3 (9.6 ± 2.0 au) 产生更高 (P < 0. 0002) 成像信号与 MB 非靶向 (1.3 ± 0.3 au) 相比，而正常乳腺和 B7-H3 阻断肿瘤中的 MBABY-B7-H3 信号显着降低 (P < 0.02) 成像信号。结论 MBABY-B7-H3 增强了乳腺肿瘤中的 B7-H3 分子信号，改善了癌症检测，同时提供了小尺寸配体和更容易生产用于临床成像的优势。