Chen Shuo, Zhou Liwu, Wang Yang
Department of Orthopedics, Jinling Hospital, Nanjing University School of Medicine, 305 Zhongshan East Road, Nanjing, 210004 China.
Cancer Cell Int. 2020 Jan 30;20:34. doi: 10.1186/s12935-020-1105-6. eCollection 2020.
Osteosarcoma (OS) is one of the most common malignant bone tumors. Plasmacytoma variant translocation 1 (PVT1) is a well-known oncogenic long noncoding RNA (lncRNA). However, to date, the regulatory mechanism of PVT1 upregulation in OS remains unknown.
qRT-PCR was carried out to test the expression level of PVT1 and ALKBH5. RNA immunoprecipitation (RIP) and RNA pull-down assays were performed to detect the interaction of PVT1 with ALKBH5 and YTHDF2. Methylated RNA immune-precipitation (MeRIP) was used to examine the -methyladenosine (mA) modification of PVT1 transcript.
In this study, we found that PVT1 expression was upregulated in OS tissues and cells and significantly related with clinical stage, tumor size, and prognosis of patients with OS. Further investigation revealed that -methyladenosine (mA) demethylase ALKBH5 could associate with PVT1 and suppress its degradation. ALKBH5 decreased the mA modification of PVT1, thus inhibiting the binding of reader protein YTHDF2 in PVT1. Functionally, ALKBH5-mediated PVT1 upregulation promoted the OS cell proliferation in vitro and tumor growth in vivo.
Our study suggests that ALKBH5-mediated mA modification of PVT1 contributes to OS tumorigenesis.
骨肉瘤（OS）是最常见的恶性骨肿瘤之一。浆细胞瘤变异易位1（PVT1）是一种著名的致癌长链非编码RNA（lncRNA）。然而，迄今为止，OS中PVT1上调的调控机制仍不清楚。
采用qRT-PCR检测PVT1和ALKBH5的表达水平。进行RNA免疫沉淀（RIP）和RNA下拉实验以检测PVT1与ALKBH5和YTHDF2的相互作用。采用甲基化RNA免疫沉淀（MeRIP）检测PVT1转录本的N6-甲基腺苷（m6A）修饰。
在本研究中，我们发现PVT1在OS组织和细胞中表达上调，且与OS患者的临床分期、肿瘤大小和预后显著相关。进一步研究发现，N6-甲基腺苷（m6A）去甲基化酶ALKBH5可与PVT1结合并抑制其降解。ALKBH5降低了PVT1的m6A修饰，从而抑制了阅读蛋白YTHDF2与PVT1的结合。在功能上，ALKBH5介导的PVT1上调促进了OS细胞的体外增殖和体内肿瘤生长。
我们的研究表明，ALKBH5介导的PVT1的m6A修饰促进了OS的肿瘤发生。
