Synthetic short RNA in cancer

Small RNAs play an important role in many biological processes. They vary widely in size and form, including single- and double-stranded RNAs. Synthetic short RNAs are very powerful tools for modulating or intervening in cellular biology, and many types of artificial oligonucleotides have been explored to mimic small RNAs. For instance, small interfering RNA (siRNA) hybridizes with target RNA to decrease protein expression by promoting RNA degradation. An aptamer binds to target molecules through non-hybridizing nucleotide-molecule interactions. Furthermore, recent findings suggest that synthetic nucleic acids utilizing extracellular mRNA sequences act on immune cells expressing RNA-binding molecules, resulting in anti-tumor effects. These molecular specificities are generated by the primary sequence of the nucleic acid and its chemical modifications. These features are applied to anti-tumor drug discovery. In this review, we summarize the basics of synthetic short RNAs and discuss their anti-tumor potential.