The prognostic value of PKM2 and its correlation with tumour cell PD-L1 in lung adenocarcinoma

BACKGROUND: The prognostic value of PKM2 and its correlation with tumour cell PD-L1 in lung adenocarcinoma (LUAD) is unclear. METHODS: A total of 506 lung adenocarcinoma samples from The Cancer Genome Atlas (TCGA) dataset and 173 LUAD tumour tissues from Jiangxi Cancer Hospital were used to analyse the correlation between PKM2 and PD-L1 expression. We further established a stable LUAD cell line with PKM2 knockdown and confirmed the association via Western blotting and flow cytometry analysis. Moreover, the prognostic values of PKM2 and PD-L1 were evaluated by the Kaplan-Meier method and Cox proportional hazards models. RESULTS: Based on the above two large cohorts, we found that PKM2 was significantly positively associated with PD-L1 expression (r = 0.132, P = 0.003 and r = 0.287, P < 0.001, respectively). Subsequently, we found that PKM2 knockdown substantially inhibited PD-L1 expression in the A549 LUAD cell line. Moreover, survival analysis showed that higher expression of PKM2 was correlated with significantly shorter overall survival (OS) and disease-free survival (DFS) in lung adenocarcinoma patients (P < 0.001 and P = 0.050, respectively). Subgroup analysis showed that lung adenocarcinoma patients who expressed high PKM2 and PD-L1 levels experienced the poorest OS and DFS. Additionally, multivariate analysis suggested that high PKM2 and PD-L1 expression was an independent prognostic indicator for worse OS and DFS (HR = 1.462, P < 0.001 and HR = 1.436, P = 0.004, respectively). CONCLUSIONS: Our results demonstrated that PKM2 regulated PD-L1 expression and was associated with poor outcomes in lung adenocarcinoma patients.