肿瘤相关巨噬细胞铁死亡在肿瘤免疫逃逸中的作用及其调控机制研究OA

Objective:To investigate the role of ferroptosis in tumor-associated macrophages(TAMs)and its regulatory mechanisms in tumor immune escape.Methods:A 4T1 breast cancer mouse model was es-tablished and divided into the following groups:BMDMs group,4T1 conditioned medium(CM)treatment group,BMDMs+RSL3 group,4T1 CM+RSL3 group,and 4T1 CM+RSL3+Fer-1 group.Primary TAMs were isolated via fluorescence-activated cell sorting(FACS)for RNA sequencing.The expression of SLC7A11(xCT)and GPX4,lipid peroxidation levels,and M1/M2 phenotypes were assessed using qRT-PCR,West-ern blotting,immunofluorescence,and flow cytometry.Ferroptosis sensitivity was validated through CCK-8 assays and Ferrostatin-1 rescue experiments.In tumor-bearing mice,the effects of the ferroptosis inducer RSL3 on tumor growth,immune cell infiltration(immunohistochemistry/multiplex immunofluorescence),and CD8+T cell function(flow cytometry for IFN-γ and Ki-67)were evaluated.Results:Compared to BMDMs,SLC7A11 expression was significantly upregulated in TAMs,and differentially expressed genes were enriched in ferroptosis-related pathways(P<0.05).4T1 CM treatment time-dependently upregulated the expression of SLC7A11 and GPX4 in BMDMs,reduced lipid peroxidation levels,and decreased sensitivity to RSL3(P<0.05).The 4T1 CM-treated group exhibited a close association with M2-like polarization(upregulation of CD206 and Arg1,downregulation of CD86)(P<0.05).In vivo experiments demonstrated that RSL3 treat-ment significantly inhibited tumor growth and remodeled the immune microenvironment:infiltration of CD4+and CD8+T cells and Granzyme B+cells within tumors increased;CD8+T cells shifted from the stroma into the tumor parenchyma and showed enhanced co-localization with tumor cells(CK19+).Concurrently,the tumor-infiltrating CD8+T cells exhibited significantly enhanced abilities to secrete IFN-γ and express Ki-67(P<0.05).Conclusions:This study reveals a novel mechanism by which the tumor microenvironment(TME)con-fers ferroptosis resistance to TAMs by upregulating the SLC7A11/GPX4 axis,thereby driving their polarization towards an M2-like immunosuppressive phenotype.Targeting and reversing ferroptosis resistance in TAMs can effectively alleviate their physical exclusion and functional suppression of CD8+T cells,reshaping the anti-tumor immune response.