A novel intronic circular RNA circFGFR1int2 up-regulates FGFR1 by recruiting transcriptional activators P65/FUS and suppressing miR-4687-5p to promote prostate cancer progression

• Published in: Journal of translational medicine Vol. 21; no. 1; pp. 1 - 840
• Main Authors: Wang, Ruyue, Zhong, Jinjing, Pan, Xiuyi, Su, Zhengzheng, Xu, Yunyi, Zhang, Mengni, Chen, Xueqin, Chen, Ni, Yu, Ting, Zhou, Qiao
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 22.11.2023; BioMed Central; BMC
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; Analysis; Antibodies; Binding sites; Care and treatment; Cell migration; Chromatin; Chromosomes; circRNA; Circular RNA; Development and progression; Epigenetics; Extracellular signal-regulated kinase; FGFR1; Fibroblast growth factor receptor 1; Fibroblast growth factors; Fibroblasts; FUS; Gene amplification; Gene mutations; Gene rearrangement; Genetic aspects; Health aspects; Hybridization; Kinases; Medical prognosis; MicroRNA; miRNA; Mutation; NF-κB protein; P65; Point mutation; Post-transcription; Prostate cancer; Proteins; Signal transduction; Sperm; Survival analysis; Therapeutic targets; Transcription factors; Transcription regulation; Tumors; China
• ISSN: 1479-5876; 1479-5876
• DOI: 10.1186/s12967-023-04718-y

Abstract Fibroblast growth factor receptor 1 (FGFR1) is a core component of the FGFs/FGFR pathway that activates multiple signalling pathways, including ERK1/2, PI3K/AKT, PLCγ, and NF-κB. Aberrant expression of FGFR1 due to gene amplification, chromosome rearrangement, point mutation, and epigenetic deregulations, have been reported in various cancers. FGFR1 overexpression has also been reported in prostate cancer (PCa), but the underlining mechanisms are not clear. Here we report a novel circular RNA, circFGFR1 int2 , derived from intron 2 of FGFR1 gene, which is overexpressed in PCa and associated with tumor progression. Importantly, we show that circFGFR1 int2 facilitates FGFR1 transcription by recruiting transcription activators P65/FUS and by interacting with FGFR1 promoter. Moreover, we show that circFGFR1 int2 suppresses post-transcriptional inhibitory effects of miR-4687-5p on FGFR1 mRNA. These mechanisms synergistically promote PCa cell growth, migration, and invasion. Overexpression of circFGFR1 int2 is significantly correlated with higher tumor grade, Gleason score, and PSA level, and is a significant unfavorable prognosticator for CRPC-free survival (CFS) ( RR  = 3.277, 95% confidence interval: 1.192–9.009; P  = 0.021). These findings unravelled novel mechanisms controlling FGFR1 gene expression by intronic circRNA and its potential clinicopathological utility as a diagnostic or therapeutic target. Graphic Abstract