由于钠/碘同向转运蛋白 (NIS) 的质膜 (PM) 定位减少，侵袭性甲状腺癌患者的消融性放射性碘 (RAI) 摄取中央治疗经常失败。我们的目的是了解 NIS 如何从人甲状腺癌细胞的 PM 中被内吞，以及这在体内是否可药物化。通过对侵袭性甲状腺癌患者内吞基因表达的分析，我们使用了诱变、NanoBiT 相互作用测定、细胞表面生物素化测定、RAI 摄取和 NanoBRET，以了解转化细胞系和患者来源的人原代甲状腺细胞中 NIS 内吞作用的机制。通过 BALB/c 小鼠中的 99mTc 高锝酸盐伽玛计数和基因表达来监测全身药物反应。我们在 NIS C 末端内鉴定出一种酸性二肽，它介导与适配器蛋白 2 (AP2) 异四聚体的 σ2 亚基的结合。我们发现 FDA 批准的药物氯喹以 AP2 依赖的功能性方式调节 PM 上的 NIS 积累。在体内，氯喹治疗 BALB/c 小鼠，与组蛋白脱乙酰酶 (HDAC) 抑制剂伏立诺他/SAHA 联合使用，可显着增强甲状腺对 99mTc 高锝酸盐的摄取，同时甲状腺 NIS mRNA 增加。生物信息学分析验证了 AP​​2 基因与 RAI 治疗的 DTC 中无病生存的临床相关性，从而能够构建 AP2 基因相关的风险评分分类器来预测复发。NIS 内化在体内是专门可药物化的。因此，我们的数据为使用 FDA 批准的药物改善侵袭性甲状腺癌患者的 RAI 治疗提供了新的可转化潜力。

Patients with aggressive thyroid cancer are frequently failed by the central therapy of ablative radioiodide (RAI) uptake, due to reduced plasma membrane (PM) localization of the sodium/iodide symporter (NIS). We aimed to understand how NIS is endocytosed away from the PM of human thyroid cancer cells, and whether this was druggable in vivo.Informed by analysis of endocytic gene expression in patients with aggressive thyroid cancer, we used mutagenesis, NanoBiT interaction assays, cell surface biotinylation assays, RAI uptake and NanoBRET to understand the mechanisms of NIS endocytosis in transformed cell lines and patient-derived human primary thyroid cells. Systemic drug responses were monitored via 99mTc pertechnetate gamma counting and gene expression in BALB/c mice.We identify an acidic dipeptide within the NIS C-terminus which mediates binding to the σ2 subunit of the Adaptor Protein 2 (AP2) heterotetramer. We discovered that the FDA-approved drug chloroquine modulates NIS accumulation at the PM in a functional manner that is AP2 dependent. In vivo, chloroquine treatment of BALB/c mice significantly enhanced thyroidal uptake of 99mTc pertechnetate in combination with the histone deacetylase (HDAC) inhibitor vorinostat/ SAHA, accompanied by increased thyroidal NIS mRNA. Bioinformatic analyses validated the clinical relevance of AP2 genes with disease-free survival in RAI-treated DTC, enabling construction of an AP2 gene-related risk score classifier for predicting recurrence.NIS internalisation is specifically druggable in vivo. Our data therefore provide new translatable potential for improving RAI therapy using FDA-approved drugs in patients with aggressive thyroid cancer.