Background:Gastric cancer (GC) remains a common malignancy worldwide with a limited understanding of the disease mechanisms. A novel circular RNA CDR1as has been recently reported to be a crucial regulator of human cancer. However, its biological role and mechanism in the GC growth are still far from clear.Methods:Small interfering RNAs (siRNAs), lentivirus or plasmid vectors were applied for gene manipulation. The CDR1as effects on the GC growth were evaluated in CCK8 and colony formation assays, a flow cytometry analysis and mouse xenograft tumor models. A bioinformatics analysis combined with RNA immunoprecipitation (RIP), RNA pull-down assays, dual-luciferase reporter gene assays, Western blot, reverse transcription–quantitative polymerase chain reaction (RT-qPCR) and functional rescue experiments were used to identify the CDR1as target miRNA, the downstream target gene and its interaction with human antigen R (HuR).Results:The CDR1as overexpression promoted the GC growth in vitro and in vivo and reduced the apoptotic rate of GC cells. Its knockdown inhibited the GC cell proliferation and viability and increased the cell apoptotic rate. Proliferation-related proteins PCNA and Cyclin D1 and apoptosis-related proteins Bax, Bcl-2, Caspase-3 and Caspase-9 were regulated. Mechanically, the cytoplasmic CDR1as acted as a miR-299-3p sponge to relieve its suppressive effects on the GC cell growth. Oncogenic TGIF1 was a miR-299-3p downstream target gene that mediated the promotive effects of CDR1as and regulated the PCNA and Bax levels. HuR interacted with CDR1as via the RRM2 domain and positively regulated the CDR1as level and its oncogenic role as well as downstream target TGIF1.Conclusions:CDR1as promotes the GC growth through the HuR/CDR1as/miR-299-3p/TGIF1 axis and could be used as a new therapeutic target for GC.
背景：胃癌（GC）在全球范围内仍是一种常见的恶性肿瘤，其发病机制尚不完全明确。近期研究发现，新型环状RNA CDR1as在人类癌症中扮演关键调控角色，但其在胃癌生长中的生物学功能与作用机制仍不清楚。 方法：研究采用小干扰RNA（siRNAs）、慢病毒或质粒载体进行基因操作。通过CCK8实验、克隆形成实验、流式细胞术分析及小鼠异种移植瘤模型评估CDR1as对胃癌生长的影响。结合生物信息学分析、RNA免疫沉淀（RIP）、RNA pull-down实验、双荧光素酶报告基因检测、Western blot、逆转录定量聚合酶链反应（RT-qPCR）及功能回复实验，系统解析CDR1as的靶向miRNA、下游靶基因及其与人抗原R（HuR）的相互作用。 结果：CDR1as过表达在体内外均能促进胃癌生长，并降低胃癌细胞凋亡率；其敲除则抑制胃癌细胞增殖活力并提高凋亡率。研究证实增殖相关蛋白PCNA、Cyclin D1及凋亡相关蛋白Bax、Bcl-2、Caspase-3、Caspase-9均受其调控。机制上，胞质CDR1as通过吸附miR-299-3p解除其对胃癌细胞生长的抑制作用。致癌因子TGIF1作为miR-299-3p下游靶基因，介导了CDR1as的促癌作用，并调控PCNA与Bax表达水平。HuR通过RRM2结构域与CDR1as相互作用，正向调控CDR1as水平及其致癌功能，同时影响下游靶标TGIF1。 结论：CDR1as通过HuR/CDR1as/miR-299-3p/TGIF1轴促进胃癌生长，可作为胃癌潜在的新型治疗靶点。
肿瘤(癌症)患者之家