Lutein reverses M2 macrophages polarization and exhibits antitumor effects on human triple-negative breast cancer cells.

BACKGROUND

Triple-negative breast cancer (TNBC) remains a major therapeutic challenge due to the lack of established molecular targets and the presence of highly infiltrating tumor-associated macrophages (TAMs), particularly the immunosuppressive M2 phenotype that drives tumor progression. This study investigated the potential of lutein, a plant-derived carotenoid with anticancer properties, to repolarize human monocyte-derived M2 macrophages into the antitumor M1 phenotype and thereby modulate the TNBC tumor microenvironment.

METHODS AND

RESULTS

CD14 + monocytes isolated from peripheral blood mononuclear cells were differentiated into M1 or M2 macrophages using GM-CSF/IFN-γ/lipopolysaccharide or M-CSF/IL-4, respectively. Lutein's effects on macrophage polarization, cell proliferation, cell migration and cytokine secretion were evaluated using flow cytometry, MTT proliferation assays, migration assays and enzyme-linked immunosorbent assays (ELISAs) in MDA-MB-231 cells. Additionally, tumor-related protein expressions from MDA-MB-231 cells were analyzed using protein arrays. Lutein significantly reduced the proliferation and migration of MDA-MB-231 cells when co-cultured with M1/M2 macrophages compared to the untreated group. IL-4 stimulation increased the expression of M2 macrophage marker (CD206) and protumor cytokines (IL-10 and TGF-β1), but lutein effectively reduced these elevated molecules in IL-4-activated macrophages. Proteomic profiling revealed that lutein downregulated several protumor proteins (survivin, VEGF, BCL-X, M-CSF, MMP-9) and upregulated antitumor markers (FKHR and GM-CSF). Furthermore, lutein markedly reduced the secretion of proinflammatory and protumorigenic cytokines and chemokines (IL-6, IL-18BPa, CCL2, CCL8, CCL7, CCL3, CCL20, and CXCL8).

CONCLUSION

These findings suggest that lutein reprograms M2 macrophages toward an M1-like phenotype and disrupts tumor-promoting signaling within the TNBC microenvironment, highlighting its potential as an adjunct therapeutic agent.