Fig. 1

Sustained IFN-β exposure represses oncostatin-M-mediated cancer stem cell properties and inhibits migration. a Sustained exposure to IFN-β (Ep/non-CSC pre-treated with IFN-β (100 IU/mL) for 48 h prior to co-treatment with OSM (10 ng/mL) and IFN-β (100 IU/mL); co-treatments for 2 weeks) represses OSM-mediated CD44 acquisition, as shown by flow cytometry (top left, 0% CD44 in NT; top right, 0% CD44 in IFN-β alone; bottom left, 18% CD44 in OSM alone; bottom right, 4% CD44 in IFN-β + OSM co-treatment). b Sustained IFN-β exposure (Ep/non-CSC pre-treated with IFN-β (100 IU/mL) for 48 h prior to co-treatment with OSM (10 ng/mL) with IFN-β (100 IU/mL); co-treatments for 3 weeks) significantly represses OSM-mediated tumor sphere initiation at limiting dilution (stem cell frequency: 1:77 for control, 1:Inf (Infinity) for IFN-β, 1:5 for OSM alone, and 1:76 for IFN-β + OSM co-treatment, ***P < 0.0001) ± SD, n = 5. c Sustained IFN-β (Ep/non-CSC pre-treated with IFN-β (100 IU/mL) for 48 h prior to co-treatment with OSM (10 ng/mL) with IFN-β (100 IU/mL); co-treatments for 4 weeks) followed by removal for 96 h significantly represses OSM-mediated cell migration in Ep/non-CSC (one-way ANOVA, **** P < 0.0001) without significantly altering the repressed migration in untreated or IFN-β alone-treated Ep/non-CSC until later time points (one-way ANOVA **P < 0.001, ± SD, 96 h). d IFN-β treatment for 48 h followed by co-treatment of IFN-β + OSM for an additional 48 h inhibits OSM-mediated EMT as demonstrated by Western analysis (prevents OSM-mediated repression of Claudin-1 and E-cadherin and inhibits OSM-mediated CD44). e Sustained IFN-β exposure (100 IU/mL, every 48 h up to 4 weeks) is non-cytotoxic/non-cytostatic to Ep/non-CSC (one-way ANOVA, ns). f Sustained IFN-β exposure (Ep/non-CSC pre-treated with IFN-β (100 IU/mL) for 48 h prior to co-treatment with OSM (10 ng/mL) with IFN-β (100 IU/mL); co-treatments for 3 weeks) maintains canonical IFN-β-signaling mediated through ISGF3 (represented by P-STAT1/STAT1/STAT2/IRF9) signaling alone or in combination with OSM. The line indicates separate Western blots using matched samples