Mechanism Of Kr(?)ppel-like Factor 15 Regulating Proliferation Of Lung Adenocarcinoma

Background:Lung adenocarcinoma(LUAD)is the most common type of non-small-cell lung cancer(NSCLC),accounting for approximately 80%of NSCLC.Although early diagnosis and early radical surgery can prolong patients' survival.However,most LUAD patients are diagnosed as advanced LUAD when the diagnosis or treatment for the first time,who have lost the chance of radical surgery.In recent years,new treatment options for patients with advanced LUAD have been provided with the advancement of immunotherapy,targeted therapy and other disciplines.However,its five-year survival rate is still not satisfactory.Numerous studies have shown that LUAD is a type of disease,and only a small number of genomic alteration status are available for clinical applications.Therefore,in-depth study of the molecular bilology and mechanism of LUAD development will contribute to promoting the progress of LUAD early diagnosis and treatment.Objective:To study the expression of KLF15 in LUAD tissues and LUAD cells,its relationship with the prognosis of patients with LUAD,and the effects of KLF15 on the proliferation of LUAD cells and its potiential mechanism.Methods:(1)Analysis of the expression of KLF15 in LUAD in TCGA datasets by bioinformatics methods,bioinformatics analysis of the effect of KLF15 expression on prognosis in LUAD;(2)using immunohistochemistry analysis of KLF15 expression in LUAD tissues and thier paired ajacent normal tissues;(3)Analysis of KLF15 mRNA expression in LUAD cells and normal lung epithelial cells by real-time fluorescent quantitative PCR;(4)Analysis of the effects of LUAD cell proliferation after transfecting with KLF15 overexpression plamids using CCK-8 assays,clony formation assays,and analysis its effect on cell cycle progress by cell flow cytometry;(5)Cell cycle related genes which had a correlation with KLF15 were studied by real-time fluorescent quantitative PCR and western blot.Results:(1)The expression of KLF15 in LUAD tissues was significantly lower than that in adjacent normal tissues by TCGA database,and its expression was positively correlated with the overall survival time of patients with LUAD;(2)The expression of KLF15 in LUAD tissues was significantly down-regulated compared with that in the para-carcinoma tissues by immunohistochemical methods;(3)The expression of KLF15 mRNA in lung adenocarcinoma cells was significantly lower than that in normal lung epithelial cells 16-HBE by qPCR methods;(4)After overexpressing KLF15 in A549 and H1299,the proliferation of LUAD cells was significantly inhibited by CCK-8 assays and the colony forming ability of LUAD cells was significantly inhibited by the colony formation assays.And cell cycle arrest was found in GO/G1 phase after overexpression of KLF15 in LUAD cell lines.(5)CDKN1A/p21 and CDKN2B/p15 gene expression was significantly up-regulated after overexpression of KLF15 in LUAD cell lines by qPCR and WB assays.Conculisons:KLF15 is down-regulated in LUAD tissues and cells,and its down-regulation is associated with prognosis in patients with LUAD.KLF15 inhibits cell proliferation,which was by upregulating CDKN1A/p21 and CDKN2B/p15 expression to regulate cell cycle progression.