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Fig. 2 | Breast Cancer Research

Fig. 2

From: The opposing effects of interferon-beta and oncostatin-M as regulators of cancer stem cell plasticity in triple-negative breast cancer

Fig. 2

IFN-β represses OSM-mediated SNAIL expression. a Acute IFN-β pre-treatment (100 IU/mL, 24 h) does not inhibit the ability of OSM (10 ng/mL, 0.5–24 h) to activate STAT3, MAPK (ERK1/2), and PI3K/AKT via phosphorylation. b IFN-β exposure (100 IU/mL, 48 h, followed by IFN-β (100 IU/mL) ± OSM (10 ng/mL) 48 h) significantly represses SNAIL mRNA as demonstrated by qRT-PCR and c SNAIL protein expression as demonstrated by Western analysis, while retaining robust, canonical IFN-β-mediated signaling (P-STAT1/STAT1/IRF9) signaling. The line indicates separate Western blots using matched samples. d IFN-β exposure (100 IU/mL, 48 h, followed by IFN-β (100 IU/mL) ± TGF-β (10 ng/mL), 48 h) significantly represses TGF-β-mediated expression of SNAIL protein with robust IFN-β-mediated signaling (P-STAT1/STAT1/IRF9) signaling. The line indicates separate Western blots using matched samples. e Sustained IFN-β (Ep/non-CSC pre-treated with IFN-β (100 IU/mL) for 48 h prior to co-treatment with TGF-β (10 ng/mL) with IFN-β (100 IU/mL); co-treatments for 3 weeks) significantly repressed TGF-β-mediated tumor sphere initiation at limiting dilution (stem cell frequency: from 1:2 TGF-β alone to 1:56 IFN-β+TGF-β; *****P < 0.00001) ± SD, n = 5. f Pharmacologic repression of TGF-β receptor (Ep/non-CSC pre-treated with TGF-βRI, SB525334, 10 μM for 48 h prior to co-treatment with either TGF-β (10 ng/mL) with SB525334 (10 μM) or OSM (10 ng/mL) with SB525334; co-treatments for 3 weeks) significantly inhibited OSM and TGF-β-mediated tumor sphere initiation at limiting dilution (stem cell frequency: from 1:2 TGF-β alone to 1:75 SB525 + TGF-β; from 1:5 OSM alone to 1:36 SB525 + OSM; *P < 0.05, ***P < 0.001, *****P < 0.0001) ± SD, n = 5

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