circRNA0001992通过内源性竞争抑制miR-20b介导甲状腺乳头状癌侵袭转移的分子机制研究

Circular RNA (circRNA) targeting microRNA (miRNA) and mediating invasion and metastasis is increasingly becoming a hot field in cancer research. Our previous study demonstrated that circRNA0001992 may be used as an early diagnostic marker for papillary thyroid carcinoma (PTC). The expression level of circRNA0001992 is closely related to lymph node metastasis and Tumor-Node-Metastasis (TNM) stage, indicating that it may be involved in the invasion and metastasis of PTC. Simultaneously, similar changes were observed in purified microvesicles (MVs) isolated from PTC cell line condition medium and patients’ peripheral blood. Further software analysis identified specific sites, located in circRNA0001992, interacting with miR-20b. Based on above results, our present study will further validate the “sponge-like” effect of circRNA0001992 on miR-20b using RNA-ISH and Luciferase technology. Then, specific cell and animal models, together with Ago2 pull-down and other techniques, were performed to monitor the effect of circRNA0001992 on proliferation, invasion and metastasis, and to investigate the role of MAPK/ERK pathway in PTC invasion and metastasis mediated by circRNA0001992-miR-20b. Eventually, using tissues and peripheral blood samples from PTC patients, we intend to analyze the correlation between circRNA0001992 and clinicopathological parameters and the key genes in MAPK/ERK pathway in order to establish a SVM model predicting PTC invasion, metastasis and prognosis. The implementation of this study will provide a theoretical basis for elucidating the molecular mechanism of invasion and metastasis of PTC.

circRNA靶向miRNA介导侵袭转移日益成为肿瘤研究的热点。我们前期鉴定出与甲状腺乳头状癌(PTC)侵袭转移和分期密切相关的circRNA0001992，在PTC细胞株培养基和患者外周血纯化的微囊泡中也检测到circRNA0001992的存在；且找到了与circRNA0001992相关的靶向miR-20b。本课题通过RNA-ISH和Luciferase等技术验证circRNA0001992对miR-20b的“海绵”作用；利用细胞和动物模型研究circRNA0001992对细胞增殖和侵袭转移的影响，探明MAPK/ERK通路在circRNA0001992-miR-20b调控PTC侵袭转移中的作用；进一步分析circRNA0001992与临床病理及MAPK/ERK通路中关键基因的关系，建立预测PTC侵袭转移和预后的SVM模型。本课题实施将为阐明PTC侵袭转移的分子机制提供理论依据。

甲状腺乳头状癌(PTC)作为内分泌系统最常见的恶性肿瘤，研究其侵袭转移的机制具有重要的临床意义。本项目探讨circRNA、miRNA及TET1在PTC中的生物学作用。我们发现circRNA0007766在甲状腺癌组织中和细胞株中表达显著下降，可能抑制PTC细胞的侵袭和转移能力；miR-3619-3p通过稳定β-catenin的mRNA而激活wnt/β-catenin通路，从而促进PTC细胞迁移侵袭；我们发现PTC中5hmC低表达是由于TET1下调引起，5hmC可作为PTC发生的新的肿瘤标记物。TET1可以抑制PTC细胞迁移及侵袭，可能通过调控经典抑癌基因miR-7、miR-15/16家族、let-7家族和相关mRNA，参与Wnt/β-catenin信号通路发挥抑癌作用。该部分研究为探索甲状腺癌的侵袭转移机制提供理论依据。. 甲状腺结节在成人的检出率高达40-66%。甲状腺超声是鉴别结节良恶性的首选无创手段，但存在15%-20%的误诊率。鉴于甲状腺结节的庞大基数，进一步提高诊断的准确率具有极其重要的临床和社会意义。我们探讨BRAFV600E在PTC血浆样本、组织样本和血细胞样本中突变情况，发现BRAFV600E基因突变是一个非常可信的与疾病相关的变异，但在PTC患者循环游离DNA (cfDNA)样本中并没有检出。为进一步寻找可靠的诊断方法，利用深度学习技术，基于近2万张甲状腺结节超声图像构建了AI诊断模型ThyNet，并与12名资深超声医师进行交互，在7个中心的数据集对模型进行了验证。ThyNet模型在外部多中心验证的准确率超过了拥有10年以上甲状腺超声经验的专家的水平。该部分研究利用规范的图像处理和标准化方法对图像进行预处理，建立了标准化的人工智能分析数据集。