Models of colorectal tumour differentiation

In vitro models in which colorectal tumour cells express differentiated and undifferentiated phenotypes have been developed and used to identify the molecular mechanisms of cellular and morphological differentiation of colorectal epithelial cells. Our data indicate that both cell-cell and cell-collagen interactions are required for the induction and maintenance of the glandular differentiation of colon carcinoma cell lines in vitro. These interactions are primarily mediated by two classes of adhesion molecules, E-cadherin and alpha 2/beta 1 integrin. Both cell surface adhesion receptors are lost in poorly differentiated colorectal tumours, and these changes may explain in part the phenotype and behaviour in vivo. Further investigation of the molecular control of integrin and cadherin function, localization and level of cell surface expression will constitute the basis of new functional assessment of tumour differentiation and likely response to treatment in colorectal cancer.