Abstract: Objective To investigate the effect of circCSE1L on the metastatic activity of nonsmall cell lung cancer NCI-H1299 cells by regulating miR-16-5p. Methods The expression level ofmiR-16-5p and circCSE1L in cancer tissues and adjacent tissues of patients with non-small cell lung cancer was analyzed by real-time quantitative PCR. NCI-H1299 cells were divided into 4 groups: si NC group, si CSE1L group, miR NC group, and miR-16-5p mimic group. The proliferation activity of cells was analyzed by MTT assay. The invasion and migration abilities of cells were analyzed by Transwell assay and wound-healing assay. The apoptosis rate of cells was analyzed by flow cytometry. Luciferase reporter gene assay was used to analyze the targeting relationship between circCSE1L and miR-16-5p in NCI-H1299 cells. Results Compared with those in the adjacent tissues, circCSE1L was highly expressed in the NSCLC tissues, while miR-16-5p was lowly expressed in the NSCLC tissues. Compared with those in the si NC group, the cell proliferation activity, invasion and migration abilities in the si CSE1L group were decreased, and the apoptosis rate was increased. Compared with those in the miR NC group, the cell proliferation activity, invasion and migration abilities of in the miR-16-5p mimic group were decreased, and the apoptosis rate was increased. The luciferase activity was decreased after transfection with miR-16-5p mimic in the CSE1LWT group compared with that in the miR NC group. Conclusion circCSE1L was highly expressedin NSCLC, while miR-16-5p was lowly expressed. circCSE1L affects the proliferation, migration, and invasion of non-small cell lung cancer NCI-H1299 cells by inhibiting the expression of miR-16- 5p, and promotes the apoptosis of non-small cell lung cancer cells.

Key words: circCSE1L, non-small cell lung cancer, metastasis, NCI-H1299 cells, miR-16-5p