Macrophage Polarization in Inflammatory Diseases

Liu, Yan-Cun; Zou, Xian-Biao; Chai, Yan-Fen; Yao, Yong-Ming

As a bidirectional modulator of immune response, TAM could definitely be a target for the treatment of tumors. TAM modulates the efficiency of chemotherapy, radiation therapy, and vascu-lar-targeted therapies with monoclonal antibodies and immunotherapy in different stages of various tumors [81] . The fact that M1 phenotype plays an anti-tumor role in the initiation of tumors, while M2 phenotype promotes the development and metastasis of tumor give a new direction for the treatment of tumors. Reeducating TAM to an anti-tumor M1 phenotype from the pro-tumor M2 phenotype in the development and metastasis stages represent a pivotal target for the immunotherapy. A recent study indicated that histidine-rich glycoprotein (HRG) could induce macrophage polarization and vessel normalization through the down-regulation of placental growth factor (PlGF), and inhibition of tumor growth as well as metastasis [82] . As NF-κB signal pathway plays an important role in the polarization of macrophages and correlates with the prognosis of tumor [73] , targeting NF-κB also means a novel direction for the treatment in the future. In brief, the recognition of mechanisms underlying multiple roles played by TAM in different stages of various tumors provides a basis for macrophage-centered therapeutic strategies.