College of Pharmacy, Chongqing Medical University, Chongqing, 400016, People's Republic of China.
Department of Clinical Laboratory, Affiliated Hospital of North Sichuan Medical College, Nanchong, 637000, People's Republic of China.
J Transl Med. 2023 Jun 20;21(1):402. doi: 10.1186/s12967-023-04235-y.
Insulin like growth factor II mRNA binding protein 3 (IGF2BP3) is an RNA binding protein with multiple roles in regulation of gene expression at the post-transcriptional level and is implicated in tumorigenesis and progression of numerous cancers including gastric cancer (GC). Circular RNAs (circRNAs) are a diverse endogenous noncoding RNA population that have important regulatory roles in cancer. However, circRNAs that regulate the expression of IGF2BP3 in GC is largely unknown.
CircRNAs that bound to IGF2BP3 were screened in GC cells using RNA immunoprecipitation and sequencing (RIP-seq). The identification and localization of circular nuclear factor of activated T cells 3 (circNFATC3) were identified using Sanger sequencing, RNase R assays, qRT-PCR, nuclear-cytoplasmic fractionation and RNA-FISH assays. CircNFATC3 expression in human GC tissues and adjacent normal tissues were measured by qRT-PCR and ISH. The biological role of circNFATC3 in GC was confirmed by in vivo and in vitro experiments. Furthermore, RIP, RNA-FISH/IF, IP and rescue experiments were performed to uncover interactions between circNFATC3, IGF2BP3 and cyclin D1 (CCND1).
We identified a GC-associated circRNA, circNFATC3, that interacted with IGF2BP3. CircNFATC3 was significantly overexpressed in GC tissues and was positively associated with tumor volume. Functionally, the proliferation of GC cells decreased significantly after circNFATC3 knockdown in vivo and in vitro. Mechanistically, circNFATC3 bound to IGF2BP3 in the cytoplasm, which enhanced the stability of IGF2BP3 by preventing ubiquitin E3 ligase TRIM25-mediated ubiquitination, thereby enhancing the regulatory axis of IGF2BP3-CCND1 and promoting CCND1 mRNA stability.
Our findings demonstrate that circNFATC3 promotes GC proliferation by stabilizing IGF2BP3 protein to enhance CCND1 mRNA stability. Therefore, circNFATC3 is a potential novel target for the treatment of GC.
胰岛素样生长因子 II mRNA 结合蛋白 3（IGF2BP3）是一种 RNA 结合蛋白，在转录后水平对基因表达具有多种调节作用，并与包括胃癌（GC）在内的许多癌症的发生和进展有关。环状 RNA（circRNAs）是一种多样化的内源性非编码 RNA 群体，在癌症中具有重要的调节作用。然而，GC 中调节 IGF2BP3 表达的 circRNAs 还知之甚少。
使用 RNA 免疫沉淀和测序（RIP-seq）筛选 GC 细胞中与 IGF2BP3 结合的 circRNAs。通过 Sanger 测序、RNase R 测定、qRT-PCR、核质分离和 RNA-FISH 测定鉴定和定位环状核因子活化 T 细胞 3（circNFATC3）。通过 qRT-PCR 和原位杂交（ISH）测量人 GC 组织和相邻正常组织中的 circNFATC3 表达。通过体内和体外实验证实 circNFATC3 在 GC 中的生物学作用。此外，进行了 RIP、RNA-FISH/IF、IP 和挽救实验，以揭示 circNFATC3、IGF2BP3 和细胞周期蛋白 D1（CCND1）之间的相互作用。
我们鉴定出一种与 GC 相关的 circRNA，circNFATC3，它与 IGF2BP3 相互作用。circNFATC3 在 GC 组织中显著过表达，并且与肿瘤体积呈正相关。功能上，体内和体外实验中 circNFATC3 敲低后，GC 细胞的增殖明显减少。从机制上讲，circNFATC3 在细胞质中与 IGF2BP3 结合，通过防止泛素 E3 连接酶 TRIM25 介导的泛素化来增强 IGF2BP3 的稳定性，从而增强 IGF2BP3-CCND1 调节轴并促进 CCND1 mRNA 稳定性。
我们的研究结果表明，circNFATC3 通过稳定 IGF2BP3 蛋白来促进 GC 增殖，从而增强 CCND1 mRNA 的稳定性。因此，circNFATC3 是治疗 GC 的潜在新靶点。
