Expression of Interleukin‐6 and Its Effect on the Cell Growth of Gastric Carcinoma Cell Lines

The expression and the effect of IL‐6 were examined in human gastric carcinoma cell lines to determine whether IL‐6 serves as a growth stimulator. The expression of IL‐6 mRNA was detected in three (TMK‐1, MKN‐1, MKN‐7) of 8 gastric carcinoma cell lines. All three cell lines secreted IL‐6 into the culture fluid, in large amounts in the cases of MKN‐1 and MKN‐7 cells. Scatchard plot analysis of IL‐6 binding revealed that MKN‐1 and MKN‐7 cells had both high‐ and low‐affinity receptors. Cell growth of MKN‐1 and MKN‐7 cells was stimulated by IL‐6, while anti‐IL‐6 antibody inhibited growth. The expression of IL‐la mRNA by these three cell lines was induced by IL‐6. IL‐la increased the expression of mRNA for IL‐6 by TMK‐1 cells. These findings indicate that IL‐6 induced by IL‐la is an autocrine growth factor for some gastric carcinomas