Fig. 6: PDK4 mediates ovarian CSC characteristics through STAT3/AKT/NF-κB/IL-8 signalling. | British Journal of Cancer

Fig. 6: PDK4 mediates ovarian CSC characteristics through STAT3/AKT/NF-κB/IL-8 signalling.

From: Ascites-derived ALDH+CD44+ tumour cell subsets endow stemness, metastasis and metabolic switch via PDK4-mediated STAT3/AKT/NF-κB/IL-8 signalling in ovarian cancer

Fig. 6

a (Left) Immunoblotting images and (right) quantification of deregulated phospho-kinases spotted on the phosphor-kinase array. b Immunoblotting showing protein expression of p-STAT3/STAT3, p-AKT/AKT and p-p65/p65 in (left) PDK4-suppressed ALDH+CD44+ SKOV3 cells, (middle) PDK4-overexpressing ALDH−CD44− SKOV3 cells and (right) ALDH+CD44+/ALDH−CD44− SKOV3 cells. qPCR analysis of relative IL-8 mRNA expression and ELISA analysis of relative IL-8 secretion in c PDK4-suppressed ALDH+CD44+ SKOV3 cells, d PDK4-overexpressing ALDH−CD44− SKOV3 cells and e ALDH+CD44+/ALDH−CD44− SKOV3 cells. f mRNA expression of relative stemness genes OCT4 and KLF4 in PDK-overexpressing ALDH−CD44− SKOV3 cells treated with IgG (2 μg/mL), CXCR1 antibody (2 μg/mL) or recombinant IL-8 (100 ng/mL) for 48 h. g Immunoblotting showing expression of p-STAT3/STAT3, p-AKT/AKT, p-p65/p65, KLF4 and BMI1 proteins in ALDH+CD44+ cells treated with the STAT3 inhibitor stattic (0, 7.5 and 10 μΜ) for 48 h. h Sphere formation assay was performed followed by imaging (scale bar, 50 μΜ) and quantification after DMAPT (1 μΜ) treatment of ALDH+CD44+ SKOV3 cells for 48 h. i mRNA expression of relative stemness genes, OCT4, SOX2, KLF4, BMI1, ALDH1 and CD44, in ALDH+CD44+ SKOV3 cells treated with the NF-κB inhibitor, DMAPT, determined via qPCR. j The sphere formation assay was performed, followed by imaging (scale bar, 50 μΜ) and quantification after DMAPT (1 μΜ) treatment of PDK4-overexpressing ALDH−CD44− SKOV3 cells for 48 h. k Relative mRNA expression of OCT4 and KLF4 as well as IL-8 in PDK4-overexpressing ALDH−CD44− SKOV3 cells treated with DMAPT, determined via qPCR. l Proposed mechanism by which PDK4 mediates cancer cell stemness in ovarian cancer through STAT3/AKT/NF-κB/IL-8 signalling. Whether PDK4 has direct interaction with STAT3, leading to its phosphorylation will be examined in future studies (*p < 0.05, **p < 0.01, results represent means ± SD from three independent experiments).

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