Icariin regulates tumor immune microenvironment
Because of efficient inhibitory effect of icariin on NF-κB signaling pathway, we hypothesized that icariin probably has ability of attenuating tumor immunosuppressive microenvironment. MDSCs which are usually accumulated in tumors are responsible for tumor immunosuppressive microenvironment(Inigo-Marco & Alonso, 2019; Wu, Tan, Hu, Zhou, Yan & Ding, 2019). So, we firstly detected the changes of tumor infiltrated CD4+ and CD8+ T cells after treatment with icariin. As shown in Figure 6M, proportion of tumor infiltrated CD4+ and CD8+ T cells were significantly increased after treatment with icariin. Additionally, icariin dramatically downregulated proportion of MDSCs in tumors in comparison with control group (Fig. 6N). Collaboratively, icariin could relieve tumor immunosuppressive microenvironment, thus enhancing antitumor effect.