<p>Myeloid-derived suppressor cells (MDSCs) significantly contribute to the immunosuppressive tumor microenvironment (TME), and targeted inhibition of MDSCs is a potential therapeutic strategy against cancer. Here, we identify macrophage receptor with collagenous structure (MARCO) as a critical regulator of MDSC differentiation and immunosuppression in breast cancer. The present study demonstrates that MARCO is expressed on MDSCs, and breast tumor-derived exosomes (TDEs) enriched with macrophage migration inhibitory factor (MIF) promote MDSC differentiation and amplify immunosuppressive activity by up-regulating MARCO. Genetic ablation of MARCO in a murine breast cancer model attenuated tumor growth, accompanied by reduced monocytic MDSCs (M-MDSCs) and total tumor-associated macrophages (TAMs), along with enhanced infiltration of CD8<sup>+</sup> T cells and natural killer (NK) cells. Furthermore, we developed a specific MARCO down-regulation-promoting monoclonal antibody that impeded TDE-induced MDSC differentiation and immunosuppression. In vivo, MARCO down-regulating antibody suppressed tumor growth and reprogrammed the TME by diminishing immunosuppressive MDSCs and TAMs and revitalizing CD8<sup>+</sup> T cells and NK cells. Strikingly, combining the MARCO down-regulating antibody with PD-1 blockade synergistically enhanced anti-tumor efficacy. This work establishes MARCO as a key regulator of MDSC-mediated immunosuppression and presents a compelling case for the inclusion of MARCO as a therapeutic target in cancer immunotherapy.</p><p></p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

MARCO expression on myeloid-derived suppressor cells is essential for their differentiation and immunosuppression

  • Sijia Liu,
  • Binle Tian,
  • Na Wang,
  • Zhilong Wang,
  • Wen Zhang,
  • Qi Li,
  • JianFei Wang,
  • Guo-Huang Fan,
  • Caicun Zhou

摘要

Myeloid-derived suppressor cells (MDSCs) significantly contribute to the immunosuppressive tumor microenvironment (TME), and targeted inhibition of MDSCs is a potential therapeutic strategy against cancer. Here, we identify macrophage receptor with collagenous structure (MARCO) as a critical regulator of MDSC differentiation and immunosuppression in breast cancer. The present study demonstrates that MARCO is expressed on MDSCs, and breast tumor-derived exosomes (TDEs) enriched with macrophage migration inhibitory factor (MIF) promote MDSC differentiation and amplify immunosuppressive activity by up-regulating MARCO. Genetic ablation of MARCO in a murine breast cancer model attenuated tumor growth, accompanied by reduced monocytic MDSCs (M-MDSCs) and total tumor-associated macrophages (TAMs), along with enhanced infiltration of CD8+ T cells and natural killer (NK) cells. Furthermore, we developed a specific MARCO down-regulation-promoting monoclonal antibody that impeded TDE-induced MDSC differentiation and immunosuppression. In vivo, MARCO down-regulating antibody suppressed tumor growth and reprogrammed the TME by diminishing immunosuppressive MDSCs and TAMs and revitalizing CD8+ T cells and NK cells. Strikingly, combining the MARCO down-regulating antibody with PD-1 blockade synergistically enhanced anti-tumor efficacy. This work establishes MARCO as a key regulator of MDSC-mediated immunosuppression and presents a compelling case for the inclusion of MARCO as a therapeutic target in cancer immunotherapy.