Fig. 6.

Stromal SULF2-dependent Hep3B growth and sorafenib sensitivity were regulated by TAK1/IKKβ/NF-κB RelA-P-ser536, with nuclear p65 associated with stromal SULF2. a Western blotting of Hep3B whole cell lysates, showed that activation of JNK/pJNK and STAT3/pSTAT3 pathways in Hep3B cells was driven by COS-7 CM independently of SULF2 and was sensitive to sorafenib treatment. b JNK inhibition limited Hep3B spheroid growth in both SULF2-dependent and independent fashion. In contrast, TAK1 (c) or IKKβ (d) inhibition limited SULF2-dependant Hep3B spheroid growth. e Similarly, Hep3B spheroid growth promoted by CM from SULF2-expressing LX-2 cells was suppressed by IKKβ inhibition. fiActivation of RelA-P-ser536 in Hep3B cells was dependent on control COS-7 CM and persistent in the presence of sorafenib, as was AKT activation. Quantification of RelA-P-ser536 (p-p65) relative to total p65 detected by Western blot is shown in fii, where data are mean ± SEM of 4 experiments. g IHC staining confirmed that SULF2 positivity in stromal cells associated with nuclear RelA-P-ser536 in adjacent tumour cells. Images are at ×20 magnification; scale bars represent 100–200 microns. Hep3B spheroid data are expressed as mean ± SEM of n = 10 experimental repeats. ns, not significant, *p = 0.05,**p < 0.01; ***p < 0.001, ****p< 0.0001.