GROWTH-STIMULATION OF A HUMAN COLORECTAL-CARCINOMA CELL-LINE BY INTERLEUKIN-1 AND INTERLEUKIN-6 AND ANTAGONISTIC EFFECTS OF TRANSFORMING GROWTH FACTOR-BETA-1

We analysed the effect of interleukin-1 (IL-1), IL-6 and transforming growth factor-beta-1 (TGF-beta-1) on the growth of a panel of eight colorectal carcinoma cell lines. IL-1 stimulated growth of two lines (LS411N and LS1034) up to 20-fold and IL-6 enhanced proliferation of LS1034 more than 5-fold. Both cytokines also augmented colony-formation of LS1034 in methylcellulose. Under both growth conditions IL-1 was the most potent stimulator. However, the addition of IL-6 to IL-1 synergistically enhanced proliferation of LS1034 in monolayer culture and additively augmented the number of colonies formed in methylcellulose. Furthermore, TGF-beta-1 strongly reduced the growth rate of LS1034. Low amounts of TGF-beta-1 markedly inhibited the response of LS1034 to IL-1 and totally abrogated proliferation induced by IL-6. We conclude that different cytokines can provide distinct signals for the regulation of growth of colorectal carcinoma cells.