TGF-β has paradoxical and context dependent effects on proliferation and anoikis in human colorectal cancer cell lines

Abstract

TGF-β is a pluripotent cytokine that can have both tumor suppressing and tumor promoting effects on epithelial cells. It is unclear what determines when TGF-β and its signaling pathway act predominantly as a tumor suppressor pathway or as a tumor-promoter pathway and whether TGF-β can have both classes of effects concurrently on a cell. We investigated the effect of TGF-β on anoikis in colorectal cancer cell lines sensitive to TGF-_-mediated growth inhibition to determine if the context of the cells could be one of the factors that would affect whether TGF-β exerts tumor suppressor or oncogene activity on colon cancer cells. We observed variable effects of TGF-_ on anoikis in these cell lines, even though they all are growth-inhibited by TGF-β. Thus, we show that TGF-β has variable effects on anoikis in colon cancer cell lines that likely reflects the effects of concurrent gene mutations in the cancer cells and the activation state of the signaling pathways controlled by these genes.