Background <p>Dysregulation of circRNA expression is associated with increased metastasis and an adverse prognosis in non-small cell lung cancer (NSCLC). Herein, this study assessed the role and regulatory mechanism of circPVT1 in NSCLC development.</p> Methods <p>CircPVT1 expression was determined using qPCR. Functional assays, including cell proliferation, colony formation, and ferroptosis-related measurements (ROS, MDA, SOD, GSH and Fe²⁺ levels), were conducted following circPVT1 knockdown. The interactions between RNA and protein were determined through RIP, dual-luciferase reporter and fluorescence in situ hybridization. Actinomycin D assay was employed to test circPVT1 stability. Additionally, tumor progression in vivo was evaluated in xenograft models with U2AF65 knockdown.</p> Results <p>CircPVT1 was significantly elevated in NSCLC samples, correlating with worse clinical outcomes. Its knockdown resulted in diminished cell proliferation and increased ferroptosis. Mechanically, circPVT1 sponges miR-338-3p, facilitating GPX4 expression, which enhanced cell proliferation. U2AF65 bound to and stabilized circPVT1, promoting cell proliferation. In animal models, U2AF65 knockdown suppressed tumor progression by regulating the circPVT1/miR-338-3p/GPX4 signaling pathway.</p> Conclusions <p>U2AF65 stabilizes circPVT1 to promote NSCLC advancement through miR-338-3p suppression and GPX4 upregulation. Thus, circPVT1 and U2AF65 may be potential therapeutic targets in NSCLC.</p> Graphical abstract <p>1. CircPVT1 is upregulated in NSCLC and correlates with poor prognosis.</p> <p>2. CircPVT1 sponges miR-338-3p to upregulate GPX4, promotes NSCLC cell proliferation and inhibits ferroptosis.</p> <p>3. U2AF65 stabilizes circPVT1, enhancing its oncogenic function and ferroptosis inhibition.</p> <p>4. U2AF65/circPVT1/miR-338-3p/GPX4 axis plays a crucial role in NSCLC tumorigenesis, providing a potential therapeutic target.</p> <p></p>