Fig. 2

TNBC-derived IL-6 activates macrophage to a TAM-like phenotype via JAK2/STAT3 axis. a Western blot analysis of the protein expression of HLF and IL-6 in shHLF or control TNBC cells. b The IL-6 secreted from the shHLF or control TNBC cells were quantified by ELISA using the anti-IL-6 mAb. c MB-231 cells subjected to ChIP assay with anti-Flag or anti-IgG antibody. d THP-1 cells were cultured with IL-6 or indicated CM for 48 h. The representative bright-field images of macrophages treated by the respective conditioned media are shown (magnification, × 200). e Expression of phospho-JAK2 and phospho-STAT3 in THP-1 cells treated with IL-6, TNBC CM in the presence or absence of control IgG or an IL-6 neutralizing antibody. f Expression of phospho-STAT3 in THP-1 cells without or with the coculture of IL-6, TNBC CM alone or with S3I-201. g Morphology of THP-1 cells without or with the coculture of IL-6, TNBC CM alone or with S3I-201. h Western blot analysis of TGF-β1 in THP-1 cells without or with the coculture of IL-6, TNBC CM alone or with S3I-201. i THP-1 cells subjected to ChIP assay with anti-phospho-STAT3 or anti-IgG antibody. j CCK-8 analysis of TNBC cells treated with CM of control TAMs, IL-6-activated TAMs alone or with LY2109761. k The schematic model of the mechanism underlying the role of HLF in TNBC ferroptosis resistance, proliferation, metastasis and chemoresistance. All results are presented as the mean ± SD, and statistical significance was assessed using a two-tailed Student’s t test. *p < 0.05