New mechanisms of radioiodide uptake revealed via a novel high throughput drug screening approach in thyroid cancer
New mechanisms of radioiodide uptake revealed via a novel high throughput drug screening approach in thyroid cancer
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DOI：
10.1101/2020.07.21.213967
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发表时间：
2020-07
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通讯作者：
Martin L Read;Katie Brookes;C. Thornton;A. Fletcher;Mohammed Alshahrani;Rashida Khan;H. Nieto;P. Borges de Souza;J. Webster;L. Alderwick;K. Boelaert;V. Smith;C. McCabe
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作者：
Martin L Read;Katie Brookes;C. Thornton;A. Fletcher;Mohammed Alshahrani;Rashida Khan;H. Nieto;P. Borges de Souza;J. Webster;L. Alderwick;K. Boelaert;V. Smith;C. McCabe
迫切需要新的组合药物策略来改善放射性碘（RAI）摄取并有效地消融甲状腺癌细胞，从而解决复发和转移性疾病。细胞碘摄取仅由钠碘同向转运体（NIS）完成，但NIS功能调节的复杂性和缺乏可靠的高通量筛选试验阻碍了进展。我们利用突变的黄色荧光蛋白（YFP）作为FDA批准的1200种药物的细胞内碘的替代生物传感器，使我们能够评估10种剂量的73种主要化合物对甲状腺癌细胞系125 I摄取的影响。随后的机制分析表明三种主要的药物作用模式：首先，一些药物抑制蛋白质VCP对NIS功能的特异性调节。其次，一些药物增强NIS表达的转录或转录后调节。第三，一些药物强烈暗示蛋白酶体降解和未折叠蛋白质反应在细胞加工NIS。利用这些机制的见解，当与药物SAHA组合时，多种化合物使放射性碘摄取显著增加。重要的是，我们的新药物组合策略在人原代甲状腺细胞中也有效，表明它们靶向内源性NIS生理学。在甲状腺乳头状癌患者中，参与蛋白质稳态的基因发生了显著改变，并预测了显著更差的结果，但仅在接受RAI治疗的患者中。总的来说，我们提出了一种新的细胞内NIS处理模型，并确定了现在可能在侵袭性甲状腺癌患者中药物治疗的关键节点。我们的数据确定了FDA批准的药物，这些药物可增强NIS加工的经典途径之外的放射性碘摄取，从而对癌症中被破坏的内源性NIS功能有了新的机制理解。
New combinatorial drug strategies are urgently needed to improve radioiodide (RAI) uptake and efficiently ablate thyroid cancer cells, thereby addressing recurrent and metastatic disease. Cellular iodide uptake is accomplished solely by the sodium iodide symporter (NIS), but the complexity of NIS functional regulation and a lack of amenable high-throughput screening assays has impeded progress. We utilised mutated yellow fluorescent protein (YFP) as a surrogate biosensor of intracellular iodide for ∼1200 FDA-approved drugs, allowing us to appraise the impact of 73 leading compounds at 10 doses on 125I uptake in thyroid cancer cell lines. Subsequent mechanistic analysis suggests three predominant modes of drug action: Firstly, a number of drugs inhibited specific regulation of NIS function by the protein VCP. Secondly, some drugs enhanced transcriptional or post-transcriptional regulation of NIS expression. Thirdly, several drugs strongly implicated proteasomal degradation and the unfolded protein response in the cellular processing of NIS. Exploiting these mechanistic insights, multiple compounds gave striking increases in radioiodide uptake when combined with the drug SAHA. Importantly, our new drug combination strategies were also effective in human primary thyrocytes, suggesting they target endogenous NIS physiology. In patients with papillary thyroid cancer, genes involved in proteostasis were remarkably altered and predicted significantly worse outcome, but only in those patients who received RAI therapy. Collectively, we therefore propose a new model of intracellular NIS processing, and identify key nodes which may now be druggable in patients with aggressive thyroid cancer. SUMMARY Our data identify FDA-approved drugs that enhance radioiodide uptake outside of the canonical pathways of NIS processing, leading to a new mechanistic understanding of endogenous NIS function which is subverted in cancer.