CircMTA2 Drives Gastric Cancer Progression through Suppressing MTA2 Degradation via Interacting with UCHL3

Our previous study has reported that metastasis-associated protein 2 (MTA2) plays essential roles in tumorigenesis and aggressiveness of gastric cancer (GC). However, the underlying molecular mechanisms ofMTA2-mediated GC and its upstream regulation mechanism remain elusive. In this study, we identified a novel circular RNA (circRNA) generated from theMTA2gene (circMTA2) as a crucial regulator in GC progression. CircMTA2was highly expressed in GC tissues and cell lines, and circMTA2promoted the proliferation, invasion, and metastasis of GC cells both in vitro and in vivo. Mechanistically, circMTA2interacted with ubiquitin carboxyl-terminal hydrolase L3 (UCHL3) to restrainMTA2ubiquitination and stabilizeMTA2protein expression, thereby facilitating tumor progression. Moreover, circMTA2was mainly encapsulated and transported by exosomes to promote GC cell progression. Taken together, these findings uncover that circMTA2suppressesMTA2degradation by interacting with UCHL3, thereby promoting GC progression. In conclusion, we identified a cancer-promoting axis (circMTA2/UCHL3/MTA2) in GC progression, which paves the way for us to design and synthesize targeted inhibitors as well as combination therapies.Keywords:CircRNAs;MTA2;gastric cancer;UCHL3;ubiquitination