Spontaneously arising, TGFβ1‐resistant colonies were isolated directly from the soft agarose plates of MOSER human colon carcinoma cells grown in the presence of TGFβ1 but in the absence of serum. The colonies were cloned by limiting dilution and screened in a monolayer proliferation assay for sensitivity to TGFβ1 and TGFβ2 isoforms. Cell clones selectively sensitive or resistant to these isoforms in the growth inhibition assay displayed similar differential sensitivities to TGFβ isoforms for production of the extracellular matrix proteins laminin and fibronectin, as well as for the expression of the colon cell differentiation marker carcinoembryonic antigen. Differential receptor binding profiles for TGFβ1 and TGFβ2 were observed among the clones. The isolation of cell clones selectively resistant or sensitive to TGFβ isoforms as well as the identification of differential receptor binding profiles among the clones indicate the heterogeneity of TGFβ responsiveness that exists naturally in human colon tumor cells and stress the importance of defining mechanisms underlying differential responsiveness to TGFβ isoforms. © 1995 Wiley‐Liss Inc.
All Science Journal Classification (ASJC) codes
- Clinical Biochemistry
- Cell Biology