Objective: Lung cancer had been leading mounts of deaths worldwide. Advances in genes microarray had helpedhuman further understand genes and identify novel circular RNAs. This study aimed at investigating the biologicalfunctions and molecular mechanisms of hsa_circ_0046264 in lung cancer which may be helpful in lung cancerearly diagnosis and clinical treatment.

Methods: Gene microarray data screened the differential gene of hsa_circ_0046264 and its downstream geneswere found by bioinformatics analysis and verified by luciferase reporter assay. QRT-PCR and Western blot was usedto detect the RNA and protein levels respectively. RNase R digestion confirmed the existences of circular RNA. Cellviability, invasion and apoptosis were determined by MTT assay, flow cytometry and DNA damage assay. Tumorformation in nude mice and immunohistochemistry proved the functions of hsa_circ_0046264 in vivo.

Results: Hsa_circ_0046264 and BRCA2 were down-regulated in lung cancer tissues while miR-1245 was up-regulated. Hsa_circ_0046264 induced apoptosis but inhibited proliferation and invasion of lung cancer cells throughtargeting miR-1245 to up-regulate BRCA2. Hsa_circ_0046264 inhibited the tumor growth in vivo.Conclusion: Hsa_circ_0046264 was a tumor suppressor in lung cancer. Overexpression of hsa_circ_0046264 couldup-regulate BRCA2 expression through down-regulating of miR-1245.