Figure 4

IL-8 is differentially expressed by MM BMSCs and can potentiate BMSC-induced NF-κB activity in RPMI8226 cells. (A) Median levels of 27 cytokines measured by cytokine array analysis in CM from 17 MM BMSCs (white bars) and 13 non-MM BMSCs (black bars). The scale is in pg/mL, and cytokines are grouped by relative concentration. Asterisk above IL-8 indicates a statistically significant difference between the groups determined by Mann-Whitney test. (B) NF-κB EMSA analysis of RPMI8226 cells treated with increasing doses of human recombinant IL-8 (top panel), and cultured alone or with BMSCs from the indicated patients with increasing amounts of anti-IL-8 neutralizing antibody as indicated (bottom panel). (C) EMSA analysis of NF-κB DNA-binding activity in RPMI8226 cells cultured alone or with BMSCs from the indicated patients with various concentrations of recombinant human IL-8. Oct-1 controls, NF-κB dimers, and fold-change in NF-κB activity was quantified and labeled as before.