Fig. 1

USP5 is highly expressed in lung cancer, and its inhibitor, EOAI, can inhibit NSCLC cell growth and colony formation. A USP5 overexpressed in NSCLC tissues. Representative pictures of IHC staining for USP5 from the weakest (− , group 1) to the strongest (+ +  + , group 4) based on increasing staining intensity. B Classification of tumor samples according to IHC staining (n = 82). The statistical significance of differences between groups was analyzed by the chi-square test of SPSS software (P < 0.01). C Effect of USP5 expression level on survival of NSCLC patients. Patients with high USP5 expression had a worse prognosis than those with low USP5 expression (P = 0.0004). D USP5 is highly expressed in NSCLC cells. By contrast, USP5 expression was up-regulated in NSCLC cells compared with normal non-epithelial cells. E Examination of the effect of EOAI on NSCLC cells cell viability. Cells were treated with DMSO or EOAI for 48 h, and viability was detected by CCK-8 kit. F Detection of the efficacy of EOAI on colony formation in NSCLC cells. NSCLC cells were treated with EOAI as indicated for 10 days, then fixed, stained, and counted. Cell colonies are shown on the left panel, and then the number of cell colonies was statistically analyzed as shown on the right panel. The t-test of GraphPad Prism8 software assessed the statistical significance of differences between groups in panels D and F. * Represents the difference between the two groups was significant (P < 0.05). All data represent at least three independent experiments (n = 3; error bar, SD)