Data_Sheet_2_LncRNA NBR2 Inhibits the Malignancy of Thyroid Cancer, Associated With Enhancing the AMPK Signaling.docx

Long non-coding RNA NBR2 is a transcript of the neighbor of BRCA1 gene 2 and can regulate tumor development. However, there is little information on the role of NBR2 in the progression of thyroid cancers (TC). Here, we show that NBR2 expression is down-regulated in TC tissues and associated with histologic subtypes of TC. NBR2 expression was variably reduced in different TC cells. While NBR2 silencing significantly enhanced the malignancy of BCPAP cells by increasing cell proliferation, clonogenicity, wound healing, and invasion as well as tumor growth in vivo, and decreasing spontaneous apoptosis, NBR2 over-expression had opposite effects in BHT101 cells. Furthermore, treatment with A-769662 (a specific AMPK activator), like NBR2 over-expression, significantly attenuated the malignancy of BHT101 cells while treatment with Compound C (a specific AMPK inhibitor) significantly rescued that NBR2-reduced malignancy of BHT101 cells. In comparison with non-tumor thyroid epithelial Nthy-ori 3-1 cells, obviously increased GLUT-1 expression, but decreased AMPK and ACC phosphorylation were detected in TC cells. While NBR2 silencing further enhanced GLUT-1 expression and reduced AMPK and ACC phosphorylation as well as the EMT process in BCPAP cells. NBR2 over-expression also had opposite effects in BHT101 cells. Similar patterns of GLUT-1 expression and AMPK and ACC phosphorylation were detected in the different types of xenograft TC tumors in vivo. Therefore, such data indicated that NBR2 acted as a tumor suppressor of thyroid cancers associated with enhancing the AMPK signaling and NBR2 may be a potential biomarker and therapeutic target for thyroid cancers.

长链非编码RNA（long non-coding RNA）NBR2是BRCA1基因2号邻位基因的转录本，可调控肿瘤发生发展。但目前关于NBR2在甲状腺癌（thyroid cancer, TC）进展中的作用的相关研究仍较为匮乏。本研究发现，NBR2在甲状腺癌组织中表达下调，且与甲状腺癌的组织学亚型密切相关；不同甲状腺癌细胞系中NBR2的表达水平存在差异性降低。NBR2沉默可通过促进BCPAP细胞的增殖、克隆形成能力、划痕愈合及侵袭能力，同时抑制细胞自发性凋亡，进而显著增强其体内成瘤能力；而过表达NBR2则在BHT101细胞中产生相反的生物学效应。此外，与NBR2过表达效果类似，特异性腺苷酸活化蛋白激酶（AMPK）激活剂A-769662处理可显著削弱BHT101细胞的恶性表型；而特异性AMPK抑制剂Compound C处理则可有效逆转NBR2过表达对BHT101细胞恶性表型的抑制作用。与正常甲状腺上皮细胞Nthy-ori 3-1相比，甲状腺癌细胞中葡萄糖转运蛋白1（GLUT-1）的表达显著上调，而AMPK及ACC的磷酸化水平显著降低。NBR2沉默可进一步上调BCPAP细胞中GLUT-1的表达，同时降低AMPK及ACC的磷酸化水平，并抑制上皮间质转化（epithelial-mesenchymal transition, EMT）过程；而过表达NBR2则在BHT101细胞中呈现相反的调控效果。体内不同类型的甲状腺癌异种移植瘤中也检测到了一致的GLUT-1表达及AMPK、ACC磷酸化水平变化趋势。综上，本研究数据表明，NBR2可通过激活AMPK信号通路发挥甲状腺癌肿瘤抑制因子的作用，其有望成为甲状腺癌潜在的诊断生物标志物及治疗靶点。