ANGPT1 promotes M1 macrophage polarization and inhibits lung adenocarcinoma progression by inhibiting the TGF-β signalling pathway.

Immune cells in the immune microenvironment of lung adenocarcinoma (LUAD) are involved in tumour progression. The aim of this study was to investigate the molecular mechanisms of immune infiltration-related genes in LUAD. The GEO, GeneCards, BioGPS and Genehopper databases were utilized to screen for immune infiltration-related differentially expressed genes (DEGs) in LUAD. Protein-protein interaction (PPI) network construction and survival analysis were performed in the Kaplan-Meier database to identify hub genes. The TIMER 2.0 database was used to analyse the correlations between hub gene expression and immune infiltration level. Co-culture of LUAD cells with macrophages and plasmid transfection to overexpress ANGPT1 were performed to investigate the function of the hub genes in LUAD using RT-qPCR, Western blot, CCK-8 assays, cell wound healing assays and transwell assays. A total of 88 immune infiltration-related DEGs were screened. The hub genes ANGPT1, CDH5 and CLDN5 were reduced in LUAD, while COL3A1 was overexpressed. ANGPT1 was significantly correlated with OS, FP and PPS, and ANGPT1 promoted the polarization of M1 macrophages. Further experiments revealed that ANGPT1 inhibited the proliferation, migration and invasion of LUAD cells by inhibiting the TGF-β signalling pathway. ANGPT1 promotes polarization of M1 macrophages and reduces the progression of LUAD by inhibiting the TGF-β signalling pathway. Thus, ANGPT1 could be employed as a predictive biomarker and immunotherapy target for lung cancer.