Oncogenic hijacking of a conserved hsa_circ_0005140/miR-762/NFIX axis drives retinoblastoma proliferation through context-dependent activation

Background: Circular RNAs play pivotal roles in cellular regulation, yet their mechanisms in retinal cells remain incompletely understood. Through comparative analysis of Y79 retinoblastoma and ARPE-19 retinal pigment epithelial cells, hsa_circ_0005140 was identified as a functionally active circRNA engaging miR-762 and nuclear factor I X (NFIX). Methods: Comprehensive functional assays included: RT-qPCR validation; Dual-luciferase reporter assays confirming molecular interactions; Phenotypic characterization (CCK-8/EdU/Transwell/Flow cytometry); Western blotting and xenograft models for in vivo validation‌. Results: Differential expression, hsa_circ_0005140 showed 596-fold higher expression in Y79 than ARPE-19 (p<0.001), yet exhibited conserved regulatory functions in both cell types. Functional axis, acts as miR-762 sponge to upregulate NFIX (60% luciferase activity reduction, p<0.001). Proliferative effects, modulated cell cycle progression and apoptosis in both Y79 (p<0.01) and ARPE-19 (p<0.05). ‌Downstream effects, hsa_circ_0005140 overexpression led to elevated IL-6/IL-8 levels (2.1-3.5 fold changes) and context-dependent TNF-α responses. In Vivo Validation‌, Xenografts showed 2.3-fold tumor growth promotion by hsa_circ_0005140 (p<0.01), reversible by miR-762 overexpression.‌ ‌Conclusions: This study establishes that ‌aberrant hsa_circ_0005140 overexpression activates a fundamental regulatory axis‌(circRNA/miR-762/NFIX) which exerts proliferative effects in both pathological and physiological contexts. The observed inflammatory marker dysregulation suggests broader functional consequences of circRNA dysregulation in retinal cells.