IL-17 inhibits the accumulation of myeloid-derived suppressor cells in breast cancer via activating STAT3

Expression of MDSC in peripheral blood of 80 BCE patients and 20 healthy volunteers was compared. Our results indicate that MDSC numbers in patients with BC were higher than healthy donors. Moreover, the clinical grade and prognosis were correlate with the number of MDSC. In this study, we investigated the effect of IL-17 on MDSCs. CCK-8 assay and flow cytometry were used to assess the proliferation and apoptosis of cells. The expression of key MDSC-related molecules was detected by western blotting. We identified administration with IL-17 in vitro significantly induced MDSC differentiation, inhibited their proliferation and triggered apoptosis. In addition, Low IL-17 inhibited the activation of STAT3, leading to increase formation of MDSCs in BC. Our results from experiments suggest that the effects of IL-17 mediate activation of STAT3 signaling in BC cells. Taken together, our study shows that MDSCs can be a new type prognostic marker in BC patient. Targeting IL-17/Stat3 signaling may be a promising strategy for BC treatment.