Exosomal circ55033 promotes cigarette smoke-induced bladder cancer by modulating EMT and stem cell properties.

Bladder cancer has high morbidity and mortality, and cigarette smoke is a major risk factor for this disease. Exosomal circRNAs are widely involved in tumor progression, while their roles in smoke-related bladder cancer remain unclear. In the present study, we identified and validated circ55033, a highly expressed circRNA in clinical samples from smoking patients. Functional experiments demonstrated that cigarette smoke induced EMT and cancer stemness in bladder cancer cells via exosome-transported circ55033. Mechanistically, circ55033 acts as a molecular sponge for miR-1286 to exert its oncogenic effects. Notably, exosomal circ55033 exhibits preliminary diagnostic capacity in patient serum and represents a promising translational candidate for non-invasive liquid biopsy biomarkers and targeted therapeutic interventions against smoking-related bladder cancer. These findings provide novel insights into the mechanisms underlying cigarette smoke-induced bladder cancer and highlight the potential of exosomal circ55033 as a preliminary candidate diagnostic and therapy biomarker.