College of Pharmacy, Chongqing Medical University, Chongqing, 400016, P.R. China.
Department of Clinical Laboratory, Affiliated Hospital of North Sichuan Medical College, Nanchong, 637000, P.R. China.
J Exp Clin Cancer Res. 2022 Aug 19;41(1):251. doi: 10.1186/s13046-022-02466-3.
Gastric cancer (GC) is one of the most common malignant tumors in China. Circular RNAs (circRNAs) are novel non-coding RNAs with important regulatory roles in cancer progression. IGF2BP3 has been found to play oncogenic roles in various cancers including GC, while the exact mechanism of IGF2BP3 is largely unknown.
The expression of IGF2BP3 in GC was evaluated by Western Blot and bioinformatics analysis. CircRNA expression profiles were screened via IGF2BP3 RIP-seq in GC. Sanger sequencing, RNase R digestion, nucleo-plasmic separation and RNA-FISH assays were used to detect the existence and expression of circARID1A. RNA ISH assay was employed to test the expression of circARID1A in paraffin-embedded GC tissues. Moreover, the function of circARID1A on cellular proliferation was assessed by CCK-8, plate colony formation, EdU assays and GC xenograft mouse model in vivo. Furthermore, the location or binding of circARID1A, IGF2BP3 protein and SLC7A5 in GC was evaluated by RNA-FISH/IF or RNA pull-down assays.
We identified a novel circRNA, circARID1A, that can bind to IGF2BP3 protein. CircARID1A was significantly upregulated in GC tissues compared with noncancerous tissues and positively correlated with tumor length, tumor volume, and TNM stage. CircARID1A knockdown inhibited the proliferation of GC cells in vitro and in vivo and circARID1A played an important role in the oncogenic function of IGF2BP3. Mechanistically, circARID1A served as a scaffold to facilitate the interaction between IGF2BP3 and SLC7A5 mRNA, finally increasing SLC7A5 mRNA stability. Additionally, circARID1A was able to directly bind SLC7A5 mRNA through complementary base-pairing and then formed the circARID1A-IGF2BP3-SLC7A5 RNA-protein ternary complex and promoted the proliferation of GC via regulating AKT/mTOR pathway.
Altogether, our data suggest that circARID1A is involved in the function of IGF2BP3 and GC proliferation, and the circARID1A-IGF2BP3-SLC7A5 axis has the potential to serve as a novel therapeutic target for GC.
胃癌（GC）是中国最常见的恶性肿瘤之一。环状 RNA（circRNAs）是一种新型的非编码 RNA，在癌症进展中具有重要的调节作用。IGF2BP3 已被发现在包括 GC 在内的各种癌症中发挥致癌作用，但其确切机制尚不清楚。
通过 Western Blot 和生物信息学分析评估 GC 中 IGF2BP3 的表达。通过 IGF2BP3 RIP-seq 在 GC 中筛选 circRNA 表达谱。通过 Sanger 测序、RNase R 消化、核质分离和 RNA-FISH 检测来检测 circARID1A 的存在和表达。RNA ISH 检测用于检测石蜡包埋 GC 组织中 circARID1A 的表达。此外，通过 CCK-8、平板集落形成、EdU 检测和 GC 异种移植小鼠模型在体内评估 circARID1A 对细胞增殖的功能。进一步通过 RNA-FISH/IF 或 RNA 下拉测定评估 circARID1A、IGF2BP3 蛋白和 SLC7A5 在 GC 中的位置或结合。
我们鉴定了一种新型 circRNA，circARID1A，它可以与 IGF2BP3 蛋白结合。与非癌组织相比，GC 组织中 circARID1A 显著上调，且与肿瘤长度、肿瘤体积和 TNM 分期呈正相关。circARID1A 敲低抑制 GC 细胞在体外和体内的增殖，circARID1A 在 IGF2BP3 的致癌功能中发挥重要作用。机制上，circARID1A 作为支架促进 IGF2BP3 和 SLC7A5 mRNA 之间的相互作用，最终增加 SLC7A5 mRNA 的稳定性。此外，circARID1A 还可以通过互补碱基配对直接结合 SLC7A5 mRNA，然后形成 circARID1A-IGF2BP3-SLC7A5 RNA-蛋白三元复合物，通过调节 AKT/mTOR 通路促进 GC 的增殖。
总之，我们的数据表明 circARID1A 参与 IGF2BP3 和 GC 增殖的功能，circARID1A-IGF2BP3-SLC7A5 轴有可能成为 GC 的一种新的治疗靶点。
