Xu Yining, Yao Teng, Ni Haonan, Zheng Rujie, Huang Kangmao, Huang Yizhen, Gao Jun, Qiao Di, Shen Shuying, Ma Jianjun
School of Medicine, Shaoxing University, Shaoxing, China.
Key Laboratory of Musculoskeletal System Degeneration and Regeneration Translational Research, Zhejiang University School of Medicine, Hangzhou, China.
Front Cell Dev Biol. 2021 Apr 22;9:642605. doi: 10.3389/fcell.2021.642605. eCollection 2021.
Recently, various studies have identified circular RNAs (circRNAs) to play a significant role in tumorigenesis, thereby showing potential as novel tumor biomarkers. circSIPA1L1 is a newly discoveredcircular RNA, which is formed by back-splicing of SIPA1L1 and is found increased in osteosarcoma (OS). Nevertheless, the specific functions of circSIPA1L1 in OS remain unknown. In the present study, circSIPA1L1 was obtained from a previously reported circRNA microarray in the GEO database (GSE96964). Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to assess the mRNA level of circSIPA1L1 in OS cell lines and tissue samples. Bioinformatics analysis, luciferase reporter assays, real-time PCR, RNA pull-down assays and RNA immunoprecipitation (RIP) were employed to verify the binding of circSIPA1L1 with miR-411-5p. Xenograft tumor models were established to identify the role of circSIPA1L1 . A series of experiments, such as western blotting, colony formation, transwell assays and anoikis assay were employed to confirm the relationship across circSIPA1L1, miR-411-5p, and RAB9A. Our study confirmed circSIPA1L1 to be upregulated in both human OS samples and OS cell lines. Mechanistically, circSIPA1L1 could serve as a miR-411-5p molecular sponge to increase RAB9A expression, which was confirmed to be a tumor promoter mediating carcinogenesis. Silencing of circSIPA1L1 attenuated the vitality, invasion, migration and proliferation of OS cell lines both and . miR-411-5p inhibition or RAB9A overexpression reversed the anti-tumor effects caused by circSIPA1L1 knockdown. Briefly, circSIPA1L1 could function as a driver gene in OS and initiate OS tumorigenesis through the miR-411-5p/RAB9A signaling pathway, which might become a potential therapeutic biomarker for OS treatment.
最近，多项研究已确定环状RNA（circRNA）在肿瘤发生中发挥重要作用，因此显示出作为新型肿瘤生物标志物的潜力。circSIPA1L1是一种新发现的环状RNA，它由SIPA1L1反向剪接形成，在骨肉瘤（OS）中表达增加。然而，circSIPA1L1在OS中的具体功能仍不清楚。在本研究中，circSIPA1L1是从GEO数据库（GSE96964）中先前报道的circRNA微阵列获得的。采用定量实时聚合酶链反应（qRT-PCR）评估circSIPA1L1在OS细胞系和组织样本中的mRNA水平。运用生物信息学分析、荧光素酶报告基因检测、实时PCR、RNA下拉检测和RNA免疫沉淀（RIP）来验证circSIPA1L1与miR-411-5p的结合。建立异种移植肿瘤模型以确定circSIPA1L1的作用。采用一系列实验，如蛋白质印迹、集落形成、Transwell检测和失巢凋亡检测，以确认circSIPA1L1、miR-411-5p和RAB9A之间的关系。我们的研究证实circSIPA1L1在人OS样本和OS细胞系中均上调。从机制上讲，circSIPA1L1可以作为miR-411-5p的分子海绵来增加RAB9A的表达，RAB9A被证实是介导肿瘤发生的肿瘤促进因子。circSIPA1L1的沉默减弱了OS细胞系在体外和体内的活力、侵袭、迁移和增殖。miR-411-5p抑制或RAB9A过表达逆转了circSIPA1L1敲低所引起的抗肿瘤作用。简而言之，circSIPA1L1可能作为OS中的驱动基因，并通过miR-411-5p/RAB9A信号通路引发OS肿瘤发生，这可能成为OS治疗的潜在生物标志物。
