Background: The presence of bone invasion in aggressive pituitary adenoma (PA) was found in our previous study, suggesting that PA cells may be involved in the process of osteoclastogenesis. miR-19a (as a key member of the miR-17-92 cluster) has been reported to activate the nuclear factor-кB (NF-кB) pathway and promote inflammation, which could be involved in the process of the bone invasion of pituitary adenoma. Methods: In this work, FISH was applied to detect miR-19a distribution in tissues from patients with PA. A model of bone invasion in PA was established, GH3 cells were transfected with miR-19a mimic, and the grade of osteoclastosis was detected by HE staining. qPCR was performed to determine the expression of miR-19a throughout the course of RANKL-induced osteoclastogenesis. After transfected with a miR-19a mimic, BMMs were treated with RANKL for the indicated time, and the osteoclast marker genes were detected by qPCR and Western Blot. Pit formation and F-actin ring assay were used to evaluate the function of osteoclast. The TargetScan database and GSEA were used to find the potential downstream of miR-19a, which was verified by Co-IP, Western Blot, and EMSA. Results: Here, we found that miR-19a expression levels were significantly correlated with the bone invasion of PA, both in clinical samples and animal models. The osteoclast formation prior to bone resorption was dramatically enhanced by miR-19, which was mediated by decreased cylindromatosis (CYLD) expression, increasing the K63 ubiquitination of tumor necrosis factor receptor-associated factor 6 (TRAF6). Consequently, miR-19a promotes osteoclastogenesis by the activation of the downstream NF-кB and mitogen-activated protein kinase (MAPK) pathways. Conclusions: To summarize, the results of this study indicate that PA-derived miR-19a promotes osteoclastogenesis by inhibiting CYLD expression and enhancing the activation of the NF-кB and MAPK pathways.
背景：我们先前的研究发现侵袭性垂体腺瘤中存在骨侵犯现象，提示垂体腺瘤细胞可能参与破骨细胞生成过程。已有报道指出miR-19a（作为miR-17-92簇的关键成员）能够激活核因子кB通路并促进炎症反应，这可能参与垂体腺瘤骨侵犯的病理过程。方法：本研究采用荧光原位杂交技术检测垂体腺瘤患者组织中miR-19a的分布特征。建立垂体腺瘤骨侵犯模型，通过转染miR-19a模拟物处理GH3细胞，采用HE染色评估破骨细胞生成程度。运用实时定量PCR检测RANKL诱导破骨细胞生成过程中miR-19a的表达动态。骨髓源性巨噬细胞转染miR-19a模拟物后，经RANKL诱导不同时间，通过qPCR和Western Blot检测破骨细胞标志基因表达。采用骨吸收陷窝形成实验和F-肌动蛋白环检测评估破骨细胞功能。通过TargetScan数据库和基因集富集分析筛选miR-19a潜在下游靶点，并运用免疫共沉淀、Western Blot和电泳迁移率变动实验进行验证。结果：临床样本和动物模型研究均显示，miR-19a表达水平与垂体腺瘤骨侵犯程度显著相关。miR-19a通过下调圆柱瘤蛋白表达，增强肿瘤坏死因子受体相关因子6的K63泛素化修饰，从而显著促进骨吸收前的破骨细胞形成过程。该机制最终通过激活下游NF-кB和丝裂原活化蛋白激酶通路促进破骨细胞生成。结论：本研究结果表明，垂体腺瘤来源的miR-19a通过抑制CYLD表达、增强NF-кB和MAPK通路激活，进而促进破骨细胞生成过程。
肿瘤(癌症)患者之家