BRAFV600E 是分化型甲状腺癌 (DTC) 中最常见的基因突变，发生在 60% 的患者中，并驱动恶性肿瘤细胞表型，包括增殖、转移和免疫逃逸。 BRAFV600E突变的甲状腺乳头状癌（PTC）还表现出甲状腺分化标志物表达大大降低，因此倾向于放射性碘（RAI）难治且预后不良。因此，了解BRAFV600E的分子机制和主要致癌事件将指导未来的治疗发展。应用生物信息学和临床标本分析、BRAFV600E诱导的PTC模型的基因操作、转录组筛选引导的功能和机制探索以及系统的挽救实验研究 BRAFV600E 诱导的甲状腺癌发展中 miR-31 的功能。此外，携带 miR-31 antagomir 的纳米颗粒被证明可以减轻 PTC 模型上的 131I 碘治疗。我们将 miR-31 确定为 BRAFV600E 相关 PTC 中显着增加的 onco-miR，通过持续的 Wnt/β 促进肿瘤进展、转移和 RAI 难治性-连环蛋白信号传导。从机制上讲，高度激活的 BRAF/MAPK 通路通过 c-Jun 介导的转录调控在体外和转基因小鼠模型中诱导 miR-31 表达。 MiR-31 反过来通过直接抑制肿瘤抑制因子 CEBPA 和 DACH1 来促进 β-连环蛋白的稳定，这两个肿瘤抑制因子指导多种重要的 Wnt/β-连环蛋白通路抑制剂的表达。遗传功能测定表明，甲状腺特异性敲除 miR-31 可抑制 BRAFV600E 诱导的 PTC 进展，并且引人注目的是，碘化钠同向转运蛋白和其他甲状腺分化标志物的表达增强，从而促进 131I 摄取。纳米颗粒介导的抗 miR-31 antagomir 的应用显着提高了 BRAFV600E 诱导的 PTC 肿瘤对 131I 治疗的放射敏感性，并有效抑制了临床前小鼠模型中的肿瘤进展。我们的研究结果阐明了一种新型 BRAF/MAPK-miR- 31-Wnt/β-catenin 调节机制是临床 BRAFV600E 相关 DTC 肿瘤发生和去分化的基础，也强调了晚期 DTC 的潜在辅助治疗策略。© 2024 作者。约翰·威利出版的《临床与转化医学》

BRAFV600E is the most common genetic mutation in differentiated thyroid cancer (DTC) occurring in 60% of patients and drives malignant tumour cell phenotypes including proliferation, metastasis and immune-escape. BRAFV600E-mutated papillary thyroid cancer (PTC) also displays greatly reduced expression of thyroid differentiation markers, thus tendency to radioactive iodine (RAI) refractory and poor prognosis. Therefore, understanding the molecular mechanisms and main oncogenic events underlying BRAFV600E will guide future therapy development.Bioinformatics and clinical specimen analyses, genetic manipulation of BRAFV600E-induced PTC model, functional and mechanism exploration guided with transcriptomic screening, as well as systematic rescue experiments were applied to investigate miR-31 function within BRAFV600E-induced thyroid cancer development. Besides, nanoparticles carrying miR-31 antagomirs were testified to alleviate 131I iodide therapy on PTC models.We identify miR-31 as a significantly increased onco-miR in BRAFV600E-associated PTC that promotes tumour progression, metastasis and RAI refractoriness via sustained Wnt/β-catenin signalling. Mechanistically, highly activated BRAF/MAPK pathway induces miR-31 expression via c-Jun-mediated transcriptional regulation across in vitro and transgenic mouse models. MiR-31 in turn facilitates β-catenin stabilisation via directly repressing tumour suppressors CEBPA and DACH1, which direct the expression of multiple essential Wnt/β-catenin pathway inhibitors. Genetic functional assays showed that thyroid-specific knockout of miR-31 inhibited BRAFV600E-induced PTC progression, and strikingly, enhanced expression of sodium-iodide symporter and other thyroid differentiation markers, thus promoted 131I uptake. Nanoparticle-mediated application of anti-miR-31 antagomirs markedly elevated radio-sensitivity of BRAFV600E-induced PTC tumours to 131I therapy, and efficiently suppressed tumour progression in the pre-clinical mouse model.Our findings elucidate a novel BRAF/MAPK-miR-31-Wnt/β-catenin regulatory mechanism underlying clinically BRAFV600E-associated DTC tumourigenesis and dedifferentiation, also highlight a potential adjuvant therapeutic strategy for advanced DTC.© 2024 The Author(s). Clinical and Translational Medicine published by John Wiley & Sons Australia, Ltd on behalf of Shanghai Institute of Clinical Bioinformatics.