Fig 2: Conditioned medium (CM) from particulate matter (PM)-treated macrophages induces epithelial-to-mesenchymal transition (EMT) in cancer cells.a Heatmap of differential gene expression between A549 CM-Control (Con) and A549 CM-PM cells identified by RNA-seq. b Gene set enrichment analysis plot for the “Epithelial-to-mesenchymal transition” gene set from the HALLMARK gene collection. NES normalized enrichment score; FWER familywise error rate; FDR false discovery rate. c Immunoblot analysis of A549 cells incubated for 24 h with the indicated concentration of CM from PM-treated THP1 cells. ß-Actin was used as the loading control. d Immunoblot analysis of A549 cells treated with CM-PM immunoprecipitated using control IgG or an anti-HBEGF antibody for 24 h. e qRT?PCR analysis of A549 cells incubated for 24 h with the indicated concentration of CM from PM-treated THP1 cells. f qRT?PCR analysis of A549 cells treated with CM-PM immunoprecipitated using control IgG or an anti-HBEGF antibody for 24 h. g Immunofluorescence analysis of A549 cells cultured with CM-PM immunoprecipitated using control IgG or an anti-HBEGF antibody for 24 h. Scale bar, 20 µm. *P = 0.05, **P = 0.01, ***P = 0.001; ns not significant.

Fig 3: Activation of the aryl hydrocarbon receptor (AhR) by particulate matter (PM) in macrophages increases HBEGF expression.a Heatmap of the differential expression of AhR-related genes between THP1-Control (Con) cells and THP1-PM2.5, THP1-PM10, and THP1-KRPM cells identified by RNA-seq. b qRT?PCR analysis of THP1 cells treated with different types of PM (25 µg/cm2) for 24 h. c Immunoblot analysis of PM2.5 (25 µg/cm2)-stimulated AhR translocation. ß-Actin and Lamin A were used as the cytoplasmic fraction and nuclear fraction loading controls, respectively. d Immunoblot analysis of THP1 cells treated with the indicated concentrations of PM2.5 for 24 h. e, f qRT-PCR (e) and ELISA (f) of THP1 cells transfected with 50 nM siAhR and treated with 25 µg/cm2 PM2.5 for 24 h. g, h qRT?PCR (g) and ELISA (h) of THP1 cells pretreated with 10 nM CH-223191 for 1 h and treated with 25 µg/cm2 PM2.5 for an additional 24 h. *P = 0.05, **P = 0.01, ***P = 0.001; ns not significant.

Fig 4: Particulate matter (PM)-treated macrophages exhibit increased HBEGF expression.a Heatmap showing the differential expression of the indicated EGFR ligands between THP1-Control (Con) cells and THP1-PM2.5, THP1-PM10, and THP1-KRPM cells identified by RNA-seq. b qRT?PCR analysis of THP1 cells treated with the indicated concentrations of different types of PM for 24 h. c ELISA of THP1 cells treated with the indicated concentrations of different types of PM for 24 h. AD Arizona dust. d Immunoblot analysis of THP1 cells treated with the indicated concentrations of different types of PM for 24 h. e qRT?PCR analysis of human cord blood-derived macrophages treated with 5 µg/cm2 PM for 24 h. f ELISA of human cord blood-derived macrophages treated with 5 µg/cm2 PM for 24 h. *P = 0.05, **P = 0.01, ***P = 0.001.

Fig 5: HBEGF secreted by particulate matter (PM)-treated macrophages increases cancer cell motility and activates EGFR in cancer cells.a ELISA of conditioned medium from particulate matter-treated cells (CM-PM) immunoprecipitated with control IgG or an anti-HBEGF antibody. b Immunoblot analysis of EGFR phosphorylation in A549 cells after treatment with CM-PM immunoprecipitated with control IgG or an anti-HBEGF antibody. c Wound healing assay of A549 cells treated with CM-PM immunoprecipitated using control IgG or an anti-HBEGF antibody. Images were acquired at 0 and 36 h. Scale bar, 250 µm. d Transwell migration (top) and invasion (bottom) assays of A549 cells treated with CM-PM immunoprecipitated using control IgG or an anti-HBEGF antibody. Scale bar, 200 µm. *P = 0.05, **P = 0.01, ***P = 0.001; ns not significant.