Analysis of circZNF609: a multifunctional circular RNA with oncogenic properties

Circular RNAs (circRNAs) are a peculiar class of stable RNAs that have a covalently closed loop structure originated from a noncanonical splicing event (back-splicing), characterized by the lack of 5’ and 3’ ends. This thesis aimed to present an overview of circRNAs’ roles, with a deep focus on a fascinating circRNA, circZNF609, which is present in many cells and seems to have multiple functions. Many latest scientific articles corroborate this idea; therefore, an analysis of most relevant studies will be presented below. Experimental evidence has revealed that circular RNAs are implicated in several diseases, most notably cancer. For this reason, the scientific community is trying to investigate the molecular mechanisms underlying the functioning of these non-linear RNA. Circular RNAs were previously thought to be non-coding; however, new studies demonstrated that circZNF609 can be translated. Moreover, this same RNA was recently found to interact with messenger RNAs via a specific intermediate complex, playing a key role in cancer progression. These functions were described respectively in myoblasts and rhabdomyosarcoma cells over the last decade by the same researcher group, suggesting that further investigations will follow for a deeper elucidation. Furthermore, although circular RNAs have long been considered as microRNA (miRNA) and protein sponges; there is still limited experimental evidence that confidently confirmed this as a universal mechanism through which circRNAs function.