Next Generation Sequencing Facilitates Quantitative Analysis of Wild Type and CANT1 Overexpression Retinoblastoma Transcriptomes

ABSTRACT: PURPOSE: Retinoblastoma (RB) is the most common malignant intraocular tumor of childhood. Recent studies have shown that long non-coding RNAs (lncRNAs), which are longer than 200 bp and without protein-coding ability, are key regulators of tumorigenesis. However, the role of lncRNAs in retinoblastoma remains to be elucidated. METHODS: LncRNA CASC15-New-Transcript 1 (CANT1) expression was determined by real-time PCR in RB cells. Tumor characteristics in CANT1-overexpressing RB cells were determined through CCK8 cell viability assay, soft agar assay and mouse xenograft experiment. RNA transcriptome-sequencing was performed to find downstream target genes of CANT1. CANT1's interactions with phosphoinositide 3-kinase gamma (PI3Kγ) were studied through chromatin oligonucleotide precipitation (ChOP) and chromatin immunoprecipitation (ChIP) assays. RESULTS: In this study, we found that the expression of lncRNA CANT1 was significantly downregulated in RB. Notably, CANT1 overexpression significantly inhibited RB growth both in vitro and in vivo. Furthermore, lncRNA CANT1, which was mainly located in the nucleus, occupied the promoter of PI3Kγ and blocked histone methyltransferase hSET1 from binding to the PI3Kγ promoter, thus abolishing hSET1-mediated histone H3K4 trimethylation of the PI3Kγ promoter and inhibiting PI3Kγ expression. Furthermore, we found that silencing PI3Kγ either by CANT1 overexpression or by PI3Kγ siRNA, reduced the activity of PI3K/Akt signaling and suppressed RB tumorigenesis. CONCLUSIONS: LncRNA CANT1 acts as a suppressor of RB progression by blocking gene-specific histone methyltransferase recruitment. These findings outline a new CANT1 modulation mechanism and provide an alternative option for RB treatment.

ORGANISM(S): Homo sapiens

PROVIDER: GSE141327 | GEO | 2020/02/05

REPOSITORIES: GEO