摘要Immunotherapy of triple-negative breast cancer(TNBC)is significantly hindered by the immunosuppressive tumor microenvironment(TME).Notably,tumor-associated macrophages(TAMs),which constitute the predominant infiltrating immune cell type in TNBC,represent a critical target for"turning off"immunosuppressive TME.Despite numerous ongoing clinical trials,current strategies exhibit limited efficacy in overcoming immunosuppressive TME.Interestingly,regulation of son of sevenless 1(SOS1),which is overexpressed in TNBC patients,shows promising potential for TAM repolarization.Herein,we developed a biomimetic liposomal platform(CCM/Cil-lipo@TD),which integrates cilengitide(Cil)-functionalized breast cancer cell membranes(CCM)to co-deliver tetrandrine(TET)and low-dose docetaxel(DTX)for TNBC therapy.This system synergistically enhanced immunotherapy by coupling SOS1 blockade-driven TAM repolarization with immune cell death(ICD)-mediated dendritic cell(DC)maturation,thereby reshaping the highly immunosuppressive TME in TNBC.Critically,the low-density Cil-anchored,CCM-fused liposomes overcome the penetration limitations inherent to conventional CCM-based delivery systems,achieving deep intratumoral accumulation of therapeutic payloads.Mechanistically,the CCM/Cil-lipo@TD ensured that TET-mediated SOS1 inhibition in tumor cells efficiently polarized TAM2(protumor)toward TAM1(antitumor).Furthermore,SOS1 blockade synergized with low-dose DTX-induced ICD to remodel TME,as evidenced by sustained cytotoxic T-cell infiltration and suppression of regulatory T cells.The CCM/Cil-lipo@TD exerted superior tumor inhibition(82.9％)in 4T1 orthotopic models and effectively inhibited postoperative local recurrence and distant metastasis.Taken together,the Cil-engineered,cell membrane-anchoring CCM/Cil-lipo@TD provides a promising approach for TNBC immunotherapy.