Role of IL-6 in tumor cell growth.

A. Effects of the IL-6-GFP silencing vector on IL-6 level in HT1197 and HT1376 cells as demonstrated by immunofluorescence analysis. Representative micrographs are shown, with the respective immunofluorescent colors (DAPI, blue; GFP, green; IL-6, red). IL-6 levels were significantly decreased by the IL-6-GFP silencing vector compared with the control-GFP vector. B. Effects of the IL-6 silencing vector on he proliferation rates of HT1197 and HT1376 cancer cells. The same number of cells (104) was plated in each plate on day 0 and allowed to grow in their respective cultures. We counted the numbers of viable cells after incubation for 2, 4, and 6 days. The y-axis represents the viable cell number. Point, mean of three separate experiments. Bars, SD. *, P<0.05. C. Effects of IL-6 inhibition on xenograft tumor growth. Each point represents the mean of three separate experiments; bars, SD; *, P<0.05. Expression of IL-6 was also evaluated by immunochemical staining of xenografts. Representative slides are shown at×400 magnification.