NCAPD3 induces M2 polarization of peripheral macrophages in lung adenocarcinoma by promoting the binding of E2F1 to the FOXM1 promoter region.

Abstract

Serving as a highly prevalent malignant tumor, lung adenocarcinoma (LUAD) is frequently associated with the establishment of an immunosuppressive tumor microenvironment during its initiation and progression, where M2-polarized macrophages exert pivotal effects. NCAPD3 acts as an oncogenic driver in multiple tumors; however, the mechanism underlying its regulation of macrophage M2 polarization in LUAD remains to be elucidated. TCGA-LUAD dataset was utilized to analyze the expression levels of NCAPD3 in patient samples from TCGA-LUAD. Following the construction of NCAPD3 overexpression and knockdown cell models and verification of transfection efficiency via qRT-PCR, flow cytometry, colony formation, Transwell, and wound-healing assays were employed to evaluate malignant phenotypes. The indirect co-culture system, accompanied by Western blot and ELISA, was subsequently employed to systematically evaluate the polarization of macrophages. Co-IP, bioinformatics analysis, ChIP, dual-luciferase reporter assay, and rescue experiments were combined to verify the regulatory effect of the NCAPD3/E2F1/FOXM1 axis on M2 macrophage polarization in LUAD. Ultimately, the effects of the NCAPD3/E2F1/FOXM1 axis on M2 polarization of macrophages in LUAD were confirmed via a rescue experiment. NCAPD3 was highly expressed in LUAD cells, and its overexpression potentiated the proliferation, migration, invasion, and anti-apoptotic capacities of tumor cells, while promoting M2 phenotypic polarization. Mechanistically, NCAPD3 upregulated FOXM1 expression by recruiting E2F1 to the FOXM1 promoter, thereby inducing M2 polarization of macrophages and accelerating malignant progression in LUAD. By interacting with E2F1, NCAPD3 facilitates the binding of E2F1 to the FOXM1 promoter region to activate FOXM1 transcription, thereby accelerating LUAD progression and triggering M2 macrophage polarization.