Fig. 4

CXCL1 but not CCL5 enhanced ABCG2 expression and contributed to doxorubicin resistance in TNBC. a Human recombinant CCL5 did not affect ABCG2 protein expression in MDA-MB-231 cells. Human recombinant CXCL1 dose-dependently increased ABCG2 protein expression (b), while CXCL1 neutralizing antibody abrogated hAdSCs’ CM-induced ABCG2 upregulation (c). d Cells were treated by 250 nM doxorubicin for 24 hours with or without the pretreatment of 24 hours’ CXCL1 (1 or 10 ng/ml), and cell viability was evaluated by crystal violet staining. e CXCL1 neutralizing antibody abrogated hAdSCs’ CM-induced doxorubicin (250 nM) resistance. IgG isotype control antibody was used as negative control. Graphs showed mean ± SD of three independent experiments. *p < 0.05; **p < 0.01; *p < 0.001 to control group. ^# p < 0.05 to hAdSCs’ CM group. ^## p < 0.01 to doxorubicin alone group. ^&&& p < 0.001 to doxorubicin in hAdSCs’ CM group. Ab CXCL1 neutralizing antibody; CM conditioned medium, con control, doxo doxorubicin, hAdSCs human adipose-derived stem cells, IgG isotype control antibody