Fig. 8

TPCA-1 significantly inhibits CXCL1^EV-dead-EV-dead-induced chemoresistance and invasion of TNBC cells co-cultured with macrophages. A, B Diagram of the CXCL1 secretion inhibitor screening assay. 4 T1 cells were treated with 80 kinds of compounds (1 μM) for 48 h, and the top five compounds with the strongest inhibitory activities on CXCL1 secretion of 4 T1 cells were selected; n = 3. C, D The cytotoxicity of TPCA-1 in TNBC 4 T1 cells (n = 8) and its effect on the apoptosis resistance of 4 T1 cells to paclitaxel (n = 3). Cells were treated as indicated for 48 h. E–G TPCA-1 treatment for 48 h had no significant effect on EV-dead secretion (E) from 4 T1 cells but significantly attenuated the concentration of CXCL1 in the supernatants of 4 T1 cells (F) and the EV-dead of apoptotic 4 T1 cells (G); n = 3. H The results of the flow cytometry assay indicated that 1 μM TPCA-1 treatment for 48 h significantly reversed the induction effect of EV-dead (50 μg/ml) on the M2 polarization of macrophages; n = 3. I, J Apoptosis and Transwell assays suggested that TPCA-1 treatment (1 μM) for 48 h inhibited 50 μg/ml EV-dead-induced apoptosis resistance (n = 3) and invasion (n = 3) of 4 T1 cells in the co-culture system; Scale bar: 100 μm. Data are presented as mean ± SD. ^*p < 0.05, ^**p < 0.01