Abstract: Objective　To investigate the expression of secreted phosphoprotein 1 (SPP1) in lung adenocarcinoma (LUAD) and its effect on the biological function of LUAD cells. Methods　The expression of SPP1 mRNA in LUAD was analyzed by UALCAN and GEPIA databases. The relationship between SPP1 mRNA expression and prognosis was analyzed by GEPIA and K-M database. The expression levels of SPP1 in LUAD tissues and cell lines was detected by real-time fluorescence quantitative PCR (qPCR) and Western blot assay. The interfering sequence targeting SPP1 was constructed and transfected into A549 cells, and cells were divided into the blank group (no transfection), the NC group (transfection with SPP1 negative control sequence) and the siSPP1 group (transfection with siRNA sequence targeting SPP1). Western blot assay was used to detect the silencing effect of SPP1 in cells. The effects of siSPP1 on the proliferation of LUAD cells were detected by CCK-8, EDU and plate clonal formation experiments. TUNEL apoptosis assay was used to detect the effect of siSPP1 on apoptosis of LUAD cells. The effects of siSPP1 on the invasion and migration of LUAD cells were detected by Transwell and scratch assay. Results　Bioinformation database analysis showed that SPP1 mRNA was highly expressed in LUAD (P＜0.05). The high expression of SPP1 mRNA was negatively correlated with the overall survival (OS) of patients with LUAD (P＜0.05). SPP1 was highly expressed in LUAD and A549 cells (P＜0.05). Silencing SPP1 could inhibit the proliferation, invasion and migration of A549 cells and induce apoptosis (P＜0.05). Conclusion　SPP1 can be a potential target in the diagnosis and treatment of lung adenocarcinoma, which may affect the occurrence and development of lung adenocarcinoma by regulating cell proliferation, migration and invasion.

Key words: lung neoplasms, adenocarcinoma, cell proliferation, apoptosis, cell movement, secreted phosphoprotein l