Thrombospondin-2 induces M2 macrophage polarization through fatty acid metabolism to drive lung adenocarcinoma proliferation.

Abstract

Tumor-associated macrophages play a critical role in regulating the progression of lung adenocarcinoma (LUAD). Platelet-derived protein thrombospondin-2 (THBS2) has been identified as a tumor marker and is known to be overexpressed in LUAD. However, the specific role of THBS2 in M2 macrophage polarization within LUAD remains unclear. We conducted bioinformatics analyses to assess the clinical significance of THBS2 expression in LUAD, which was subsequently validated using quantitative PCR. We examined the relationship between THBS2 expression and M2 macrophage infiltration. A coculture system of LUAD cells and M0 macrophages was established to investigate the influence of THBS2 on macrophage infiltration and polarization through immunofluorescence and ELISA. We explored the impact of THBS2 on fatty acid metabolism (FAM) using oil red O staining and relevant kits and elucidated the role of THBS2 in regulating M2 macrophage polarization and LUAD proliferation through cell counting kit-8 (CCK-8) and colony formation assays. Western blot was employed to assess expression changes of Bax and Bcl-2. THBS2 was highly expressed in LUAD and was associated with poor prognosis in patients. In-vitro experiments demonstrated that silencing THBS2 significantly inhibited macrophage infiltration and polarization. THBS2 primarily activated FAM pathways, inducing M2 macrophage polarization and promoting LUAD cell proliferation. THBS2 enhanced LUAD proliferation by regulating FAM to induce M2 macrophage polarization. These findings provide a theoretical basis for targeting THBS2 as a novel therapeutic strategy in LUAD.