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Bone marrow cells are differentiated into MDSCs by BCC-Ex through down-regulating the expression of CXCR4 and activating STAT3 signalling pathway |
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| Authors: | Quan-Wen Liu Yong Chen Jing-Yuan Li Ling Xiao Wen-Jie Zhang Jia-Le Zhao Hao-Cheng Gu Han-You Wu Guo-Si-Lang Zuo Ke-Yu Deng Hong-Bo Xin |
| Affiliation: | 1. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China Contribution: Conceptualization (equal), Data curation (equal), Formal analysis (equal), Funding acquisition (equal), Methodology (equal), Project administration (equal);2. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China Contribution: Data curation (equal), Investigation (equal);3. School of Chemistry, Biology and Material Science, East China University of Technology, Nanchang, China Contribution: Data curation (equal), Investigation (equal);4. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China Contribution: Formal analysis (equal);5. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China Contribution: Investigation (equal);6. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China School of Life and Science, Nanchang University, Nanchang, China Contribution: Data curation (equal);7. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China Contribution: Software (equal);8. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China Contribution: Methodology (equal);9. The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China |
| Abstract: | Studies showed that the increase of myeloid-derived suppressor cells (MDSCs) in tumour microenvironment is closely related to the resistant treatment and poor prognosis of metastatic breast cancer. However, the effect of tumour-derived exosomes on MDSCs and its mechanism are not clear. Here, we reported that breast cancer cells (4T1)-secreted exosomes (BCC-Ex) were able to differentiate bone marrow cells into MDSCs and significantly inhibited the proliferation of T lymphocytes to provide an immunosuppressive microenvironment for cancer cells in vivo and in vitro. The number of MDSCs in bone marrow and spleen of 4T1 tumour-bearing mice and BCC-Ex infused mice was significantly higher than that of normal mice, whereas the number of T lymphocytes in spleen was significantly decreased. In addition, BCC-Ex markedly promoted the differentiation of MDSCs from bone marrow cells or bone marrow cells derived macrophages, seen as the increased expressions of MDSCs-related functional proteins Arginase-1 (Arg-1) and inducible nitric oxide synthase (iNOS). Furthermore, BCC-Ex significantly down-regulated the expressions of chemokine receptor CXCR4 and markedly up-regulated the levels of inflammatory cytokines IL-6 and IL-10 in bone marrow cells and macrophages and remarkably inhibited the division and proliferation of T cells. Importantly, CXCR4 agonist, CXCL12, could reverse the function of BCC-Ex, indicating that BCC-Ex-induced MDSCs might be dependent on the down-regulation of CXCR4. Western blot showed that BCC-Ex significantly promoted the phosphorylation of STAT3 in bone marrow cells, resulting in the inhibitions of the proliferation and apoptosis of bone marrow cells, and the aggravation of the differentiation of bone marrow cells into MDSCs. |
| Keywords: | breast cancer CXCR4 exosomes MDSCs STAT3 |