Oncogenic RAS regulates long non-coding RNA Orilnc1 in human cancer

RAS and its downstream cascades transmit cellular signals resulting in increased transcription of genes involved in cell growth and division. Protein-coding gene targets of RAS signaling have been characterized extensively, but long non-coding RNAs (lncRNA) regulated by these processes have not. Using a custom-designed lncRNA microarray, we identified the lncRNA Orilnc1 as a genetic target of RAS that is critical for RAS oncogenicity. Orilnc1 expression was regulated by RAS-RAF-MEK-ERK signaling via the transcription factor AP1. Orilnc1 was highly expressed in BRAF-mutant cancers such as melanoma. Silencing of Orilnc1 blocked tumor cell proliferation and growth in vitro and in vivo. Additionally, Orilnc1 blockade reduced expression of Cyclin E1 and induced G1/S cell cycle arrest in tumor cells. Taken together, our results identify Orilnc1 as a novel, non-protein mediator of RAS/RAF activation which may serve as a therapeutic target in RAS/RAF-driven cancers.