circCDYL2 promotes invasion and migration of nasopharyngeal carcinoma via enhancing CDC42-mediated cytoskeletal remodeling

Multiple circular RNAs (circRNAs) have been implicated in the development and progression of nasopharyngeal carcinoma (NPC). However, the biological functions and regulatory mechanisms of many circRNAs remain poorly understood. In our previous study, we identified circCDYL2 as highly expressed in NPC tissues and demonstrated its role in promoting radiotherapy resistance by enhancing homologous recombination repair. In this study, we further show that circCDYL2 promotes the invasive and migratory abilities of NPC cells. Mechanistically, circCDYL2 functions as a scaffold that binds to the 3'-UTR of CDC42 mRNA through reverse complementary base pairing, while simultaneously recruiting polypyrimidine tract-binding protein 1 (PTBP1) to this region, thereby stabilizing CDC42 mRNA. This stabilization facilitates cytoskeletal remodeling in NPC cells, reducing cellular stiffness and adhesion and ultimately enhancing their invasive and migratory capacities. These findings reveal a novel circCDYL2/PTBP1/CDC42 regulatory axis in NPC progression and underscore potential molecular markers and therapeutic targets for clinical intervention.