Objective To investigate the relationship between the expression of Holliday junction recognition protein(HJURP) in lung cance tissues and prognosis of patients with lung adenocarcinoma(LUAD), and to explore the effect of HJURP on proliferation of LUAD cells(H1299 and SPC-A1). Methods Human non-small cell lung cancer (NSCLC) tissues and paired normal lung tissues(n=17) were collected from Department of Oncology of Rocket Force Medical Center from February 2019 to May 2020. RT-qPCR and Western blotting were applied to analyze the expression of HJURP in NSCLC tissues and normal tissues. Public available databases, the cancer genome atlas (TCGA) and Kaplan-Meier Plotter(KM-plot), were used to analyze the expression of HJURP of LUAD tissues and normal tissues and the predictive effect of prognosis in patients with LUAD. 5-ethynyl-2-deoxyuridine (EDU) incorporation assay was applied to investigate the effect of knock-dowm HJURP on the proliferation of cancer cell lines (H1299, SPC-A1). Pearson correlation analysis was used to analyze the relationship between HJURP and the expression of forkhead box protein M1(FOXM1). Chromatin immunoprecipitation(ChIP) assay was used to analyze the transcription regulation effect of FOXM1 on HJUPR. Dual-luciferase reporter assay was used to analyze the combination of FOXM1 and HJURP promoter. SiRNA was used to knock down FOXM1, which could detect the effect on the expression of HJURP. Results Compared with normal lung tissues, LUAD tissues had increased HJURP expression via RT-qPCR and Western blotting(P < 0.05). Increased HJURP expression in tumor tissues was correlated with a poor prognosis of patients with LUAD based on survival analysis of LUAD patients in TCGA and KM-plot(P < 0.05). Knock-down of HJURP inhibited the proliferation of H1299 (P < 0.05) and SPC-A1(P < 0.05) cells. The expression of FOXM1 correlated positively with HJURP in LUAD (medical center: r=0.581 3, P < 0.05; TCGA: r=0.877 6, P < 0.05; CCLE: r=0.455 1, P < 0.05). The results of ChIP assay and dual-luciferase reporter assay showed FOXM1 could combine the promoter region of HJURP. The expression of HJURP decreased after knocking down FOXM1(P < 0.05). Conclusion HJURP is involved in the regulation of the proliferation of LUAD cells. Increased HJURP expression in LUAD tissues is related to a poor prognosis. FOXM1 is the main upstream transcription factor for regulating HJURP.
