Journal Article

Circular RNA circNRIP1 acts as a microRNA-149-5p sponge to promote gastric cancer progression via the AKT1/mTOR pathway

Xu, Jianghao, Zhang, Xing, Wang, Sen, Xu, Zekuan, Sun, Guangli, Huang, Xiaoxu, Chen, Zheng, Cao, Jiacheng, Xu, Penghui, Lv, Jialun, Wang, Haixiao

2019

Overview

Background CircRNA has emerged as a new non-coding RNA that plays crucial roles in tumour initiation and development. ‘MiRNA sponge’ is the most reported role played by circRNAs in many tumours. The AKT/mTOR axis is a classic signalling pathway in cancers that sustains energy homeostasis through energy production activities, such as the Warburg effect, and blocks catabolic activities, such as autophagy. Additionally, the AKT/mTOR axis exerts a positive effect on EMT, which promotes tumour metastasis. Methods We detected higher circNRIP1 expression in gastric cancer by performing RNA-seq analysis. We verified the tumour promotor role of circNRIP1 in gastric cancer cells through a series of biological function assays. We then used a pull-down assay and dual-luciferase reporter assay to identify the downstream miR-149-5p of circNRIP1. Western blot analysis and immunofluorescence assays were performed to demonstrate that the circNRIP1-miR-149-5p-AKT1/mTOR axis is responsible for the altered metabolism in GC cells and promotes GC development. We then adopted a co-culture system to trace circNRIP1 transmission via exosomal communication and RIP experiments to determine that quaking regulates circNRIP1 expression. Finally, we confirmed the tumour suppressor role of microRNA-133a-3p in vivo in PDX mouse models. Results We discovered that knockdown of circNRIP1 successfully blocked proliferation, migration, invasion and the expression level of AKT1 in GC cells. MiR-149-5p inhibition phenocopied the overexpression of circNRIP1 in GC cells, and overexpression of miR-149-5p blocked the malignant behaviours of circNRIP1. Moreover, it was proven that circNRIP1 can be transmitted by exosomal communication between GC cells, and exosomal circNRIP1 promoted tumour metastasis in vivo. We also demonstrated that quaking can promote circNRIP1 transcription. In the final step, the tumour promotor role of circNRIP1 was verified in PDX models. Conclusions We proved that circNRIP1 sponges miR-149-5p to affect the expression level of AKT1 and eventually acts as a tumour promotor in GC.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Adenocarcinoma - genetics / Adenocarcinoma - metabolism / Adenocarcinoma - mortality / Adenocarcinoma - pathology / Aged / AKT protein / AKT1 / AKT1 protein / Analysis / Angiogenesis / Animal models / Animals / Autophagy / Binding sites / Biomedical and Life Sciences / Biomedicine / Biosynthesis / Bladder cancer / Breast cancer / Cancer / Cancer cells / Cancer metastasis / Cancer Research / Cell adhesion & migration / Cell culture / Cell growth / Cell Line, Tumor / Cell Movement / Cell Proliferation / ceRNA / circRNA / Circular RNA / Development and progression / Disease Progression / Energy balance / Exosomes - metabolism / Exosomes - pathology / Female / Fluorescent antibody technique / Gastric cancer / Gene Expression Regulation, Neoplastic / Heterografts / Homeostasis / Humans / Immunofluorescence / Kidney cancer / Kinases / Liver cancer / Luciferase / Lymphatic Metastasis / Male / Medical prognosis / Metabolism / Metastases / Metastasis / Mice / MicroRNA / MicroRNAs / MicroRNAs - genetics / MicroRNAs - metabolism / Middle Aged / miRNA / Neoplasm Staging / Non-coding RNA / Oncology / Organoid / Phagocytosis / Proteins / Proto-Oncogene Proteins c-akt - genetics / Proto-Oncogene Proteins c-akt - metabolism / RNA / RNA - antagonists & inhibitors / RNA - genetics / RNA - metabolism / RNA, Circular / RNA, Small Interfering - genetics / RNA, Small Interfering - metabolism / Roles / Signal Transduction / Stomach cancer / Stomach Neoplasms - genetics / Stomach Neoplasms - metabolism / Stomach Neoplasms - mortality / Stomach Neoplasms - pathology / Survival Analysis / TOR protein / TOR Serine-Threonine Kinases - genetics / TOR Serine-Threonine Kinases - metabolism / Transcription / Tumors