Fig. 5

hCG-driven collaborative elicitation of IL-6 and consequent chemo-resistance. a Cell viability analysis on COLO-205 (top panel) and ChaGo-K-1 (bottom panel) cells pre-incubated with recombinant IL-6 and later exposed to curcumin. Means ± SEM of four independent experiments (with three replicates) are shown. For each cell line and for both control cultures and cultures containing hCG, data has been individually normalized to cells plus vehicle control (VC).(*p < 0.0009, ^~p < 0.006, ^#p < 0.0001, ^%p < 0.03, ^&p < 0.0001, ^>p < 0.0004 vs cells not exposed to IL-6 at the same drug concentration). b Levels of TNF-α and IL-6 in supernatants of peripheral blood adherent cells (PBACs) exposed to hCG or to tumor-conditioned medium (TCM) derived from either control or from hCG-pre-incubated COLO-205 (left top and bottom panels) and ChaGo-K-1 (right top and bottom panels) cells. The effects of concurrent incubation with anti-hCG antibodies or isotype control (I.C.) antibodies are also shown (^$p < 0.0001,*p < 0.0002, ^%p < 0.0004, ^#p < 0.0008). c Assessment of the ability of IL-6 (in supernatants of PBACs obtained upon incubation with hCG tumor-conditioned medium) to mediate resistance to curcumin in COLO-205 (left panel) and ChaGo-K-1 (right panel) cells. The relative efficacies of anti-IL-6 antibodies and isotype control (I.C.) antibodies to neutralize the protective effects of IL-6 are also shown. The right-most bars in each graph represent controls cultures in which only medium was dispensed to which data has been individually normalized. (*p < 0.0003, ^#p < 0.001). For b and c, means ± SEM of three independent experiments (with three replicates) are shown