The pan-cancer lncRNA PLANE regulates an alternative splicing program and promotes cancer pathogenesis

Genomic amplification of the distal portion of chromosome 3q that encodes a number of oncogenic proteins is one of the most prevalent chromosomal deformities. Here we functionally characterise a non-protein product of this region, the long noncoding RNA (lncRNA) PLANE, which is upregulated in diverse cancer types through copy number gain as well as transcriptional activation by E2F1. PLANE forms an RNA-RNA duplex with the nuclear receptor co-repressor 2 (NCOR2) pre-mRNA at intron 45, binds to heterogeneous ribonucleoprotein M (hnRNPM) and facilitates the association of hnRNPM with the intron, leading to repression of the alternative splicing (AS) event generating NCOR2-202, a major protein-coding NCOR2 AS variant. As such, PLANE promotes cancer cell proliferation and tumorigenicity and its upregulation is associated with poor outcome of patients. These results uncover the function and regulation of PLANE and suggest that PLANE may constitute a therapeutic target in the pan-cancer context. For RNA-seq analysis of PLANE siRNA versus control siRNA, the A549 cells were transfected with siRNAs for 48 hours before harvesting.