The stimulator of interferon genes (STING) is pivotal in mediating STING-dependent type I interferon production, which is crucial for enhancing tumor rejection. Visualizing STING within the tumor microenvironment is valuable for STING-related treatments, yet the availability of suitable STING imaging probes is limited. In this study, we developed [¹⁸F]AlF-ABI, a novel ¹⁸F-labeled agent featuring an amidobenzimidazole core structure, for positron emission tomography (PET) imaging of STING in B16F10 and CT26 tumors. [¹⁸F]AlF-ABI was synthesized with a decay-corrected radiochemical yield of 38.0 ± 7.9% and radiochemical purity exceeding 97%. The probe exhibited a nanomolar STING binding affinity (K_D = 35.6 nM). Upon administration, [¹⁸F]AlF-ABI rapidly accumulated at tumor sites, demonstrating significantly higher uptake in B16F10 tumors compared to CT26 tumors, consistent with STING immunofluorescence patterns. Specificity was further validated through in vitro cell experiments and in vivo blocking PET imaging. These findings suggest that [¹⁸F]AlF-ABI holds promise as an effective agent for visualizing STING in the tumor microenvironment.

中文翻译：

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18F 标记的氨基苯并咪唑类似物用于可视化肿瘤中 STING 的表达

干扰素基因刺激剂 (STING) 在介导 STING 依赖性 I 型干扰素产生方面至关重要，这对于增强肿瘤排斥至关重要。肿瘤微环境中 STING 的可视化对于 STING 相关治疗很有价值，但合适的 STING 成像探针的可用性有限。在这项研究中，我们开发了[ ¹⁸ F]AlF-ABI，一种新型¹⁸ F 标记试剂，具有酰胺苯并咪唑核心结构，用于 B16F10 和 CT26 肿瘤中 STING 的正电子发射断层扫描 (PET) 成像。合成的[ ¹⁸ F]AlF-ABI的衰变校正放射化学产率为38.0±7.9%，放射化学纯度超过97%。该探针表现出纳摩尔级 STING 结合亲和力 ( KD = _35.6 nM)。施用后，[ ¹⁸ F]AlF-ABI在肿瘤部位快速积累，表明与CT26肿瘤相比，B16F10肿瘤中的摄取显着更高，与STING免疫荧光模式一致。通过体外细胞实验和体内阻断 PET 成像进一步验证了特异性。这些发现表明[ ¹⁸ F]AlF-ABI有望成为肿瘤微环境中STING可视化的有效试剂。