Role of IL-6 in tumor growth. a. Effect of an IL-6-GFP silencing vector on the level of IL-6 in CE81T, as assessed by immunofluorescence and immunoblotting. The results of representative slides are shown. The IL-6-GFP silencing vector as compared with that with control-GFP vector significantly reduced IL-6 levels. b. Effect of IL-6 on the proliferation of CE81T cancer cells as determined by viable cell counting. The same number of cells (104) were plated in each plate on day 0 and allowed to grow in their respective cultures. We counted the number of viable cells after incubation for 2, 4 and 6 days. The Y axis represents the viable cell number. Point, means of three separate experiments; bars, SD. *, p < 0.05. c. Effect of IL-6 inhibition on tumor xenograft growth. Data represent the means ± SD of three independent experiments. *, p < 0.05. IL-6 expression was also evaluated by IHC staining of xenografts. Representative slides are shown. d. Effect of IL-6 inhibition on cell death, as assessed by FACS and immunofluorescence staining. The results of representative slides are shown.