The potential therapeutic applications of long non-coding RNAs

The field of RNA-based therapeutics is rapidly evolving and targeting non-coding RNAs (ncRNAs) associated with disease is becoming increasingly feasible. MicroRNAs (miRNAs) are a class of small ncRNAs (sncRNAs) and the first anti-miRNA drugs, e.g., Miravirsen and Cobomarsen, have successfully completed phase II clinical trials. Long ncRNAs (lncRNAs) are another class of ncRNAs that are commonly dysregulated in disease. Thus, they hold potential as putative therapeutic targets or agents. LncRNAs can function through a variety of mechanisms, including as guide, scaffold or decoy molecules, and understanding of these actions is critical to devising effective targeting strategies. LncRNA expression can be modulated with small interfering RNAs (siRNAs), antisense oligonucleotides (ASOs), CRISPR-Cas9, or small molecule inhibitors. These approaches have been employed to target a number of lncRNAs and tested in animal models of disease, including targeting ANRIL for non-small cell lung cancer and H19 for pancreatitis. However, there are currently no clinical trials registered in the ClinicalTrials.gov database that target lncRNAs as a therapeutic intervention. In order to translate lncRNA targeting into clinical use, several limitations must be overcome, such as potential toxicity and off-target effects. Overall, while significant progress has been made in the field, further development is required before the clinical application of the first therapeutics targeting lncRNAs. In this review, we discuss recent advances in our understanding of the mechanisms of action of lncRNAs that present avenues for clinical therapeutic targeting and consider off-target effects as a limiting factor in their application.