Background:BCAR3has been implicated in various cancers, yet its role in thyroid cancer (TC) remains unclear. This study aimed to investigate the methylation status, functional effects, and underlying mechanisms ofBCAR3in TC. Methods:BCAR3methylation was analyzed using matrix-assisted laser desorption/ionization–time-of-flight (MALDI-TOF) mass spectrometry in 422 TC and 371 benign thyroid nodule samples. Expression levels were assessed via immunohistochemistry, qPCR, and Western blot. Functional assays including proliferation, migration, and invasion were performed afterBCAR3knockdown. Rescue experiments using a PI3K activator were conducted to examine pathway mechanisms. Results:BCAR3was significantly hypomethylated in TC compared to benign tissues (p< 0.001), with CpG_6 most strongly associated with TC risk (odds ratio, OR = 1.73,p< 0.001). Notably,BCAR3hypomethylation was more pronounced in cases with larger tumor size and advanced disease stage. Furthermore,BCAR3methylation showed differential patterns across TC subtypes, with medullary thyroid carcinoma exhibiting the lowest methylation levels. BCAR3 expression was upregulated in TC tissues and cell lines (p< 0.05). Mechanistically,BCAR3knockdown reduced phosphorylation of AKT/mTOR and altered expression of epithelial-to-mesenchymal transition (EMT) marker, characterized by an increase in E-cadherin and decreases in Vimentin and N-cadherin, and consequently suppressed proliferation, migration, and invasion (p< 0.05). Rescue experiments with a PI3K activator showed a trend towards restoration of these effects, although not to the level of the control groups. Conclusions:BCAR3hypomethylation contributes to TC cells’ proliferation, migration, and invasion by promoting AKT/mTOR activation and EMT. These findings highlight the potential ofBCAR3methylation as both a biomarker and a therapeutic target in TC.
背景：BCAR3基因在多种癌症中发挥作用，但其在甲状腺癌（TC）中的角色尚不明确。本研究旨在探讨BCAR3在甲状腺癌中的甲基化状态、功能效应及其潜在机制。方法：采用基质辅助激光解吸电离飞行时间质谱技术对422例甲状腺癌组织和371例良性甲状腺结节样本进行BCAR3甲基化分析。通过免疫组化、定量PCR和蛋白质印迹评估表达水平。在敲低BCAR3后进行了增殖、迁移和侵袭等功能实验。使用PI3K激活剂进行挽救实验以探究通路机制。结果：与良性组织相比，BCAR3在甲状腺癌中呈显著低甲基化状态（p<0.001），其中CpG_6位点与甲状腺癌风险关联最强（比值比OR=1.73，p<0.001）。值得注意的是，在肿瘤体积较大和疾病分期较晚的病例中，BCAR3低甲基化更为明显。此外，不同甲状腺癌亚型中BCAR3甲基化呈现差异模式，髓样甲状腺癌的甲基化水平最低。BCAR3在甲状腺癌组织和细胞系中表达上调（p<0.05）。机制上，敲低BCAR3可降低AKT/mTOR磷酸化水平，并改变上皮-间质转化标志物的表达——表现为E-钙黏蛋白增加，波形蛋白和N-钙黏蛋白减少，从而抑制增殖、迁移和侵袭能力（p<0.05）。PI3K激活剂的挽救实验显示这些效应有恢复趋势，但未达到对照组水平。结论：BCAR3低甲基化通过激活AKT/mTOR通路和促进上皮-间质转化，促进甲状腺癌细胞的增殖、迁移和侵袭。这些发现表明BCAR3甲基化有潜力成为甲状腺癌的生物标志物和治疗靶点。
肿瘤(癌症)患者之家