Expression and role of integrins in adhesion of human colonic carcinoma cells to extracellular matrix components

Abstract

We have examined integrin expression and function in the human colon carcinoma cell line HT29, and in clonal sublines derived from the HT29 line. These cells express several different integrin subunits including beta 1, alpha 2, 3, 6 and alpha v, but do not express the classic alpha 5/beta 1 fibronectin receptor. Clonal variation in the pattern of integrin expression was quite limited. The profile of integrin expression correlates well with the adhesive behavior of HT29 cells. Thus the cells adhere well to vitronectin, laminin and type IV collagen, but not at all to fibronectin. Adhesion to collagen was completely blocked by an anti-beta 1 monoclonal antibody, indicating that beta 1 integrins mediate this process. Adhesion to laminin was strongly blocked by anti-beta 1 monoclonal or anti-beta 6 monoclonal, suggesting that the alpha 6/beta 1 complex functions in attachment to laminin; this was somewhat surprising since immunoprecipitation experiments indicate that most of the alpha 6 subunit seems to be associated with the beta 4 subunit. Despite their strong adherence to laminin, collagen and vitronectin, HT29 cells are not very motile and, in response to gradients of these proteins, do not migrate nearly as well as CHO cells tested under similar conditions. Since HT29 cells can undergo an enterocyte-like differentiation in glucose-free medium, we compared integrin expression in HT29 and its subclones during the process of differentiation. There was no correlation between the state of differentiation, as assessed by expression of brush-border hydrolases, and the level of expression of any of the integrin subunits measured. Thus the pattern of integrin expression in these colonic tumor cells seems to be a characteristic of the cell line, and is not readily modified by changes in cell growth or differentiation.

Different adhesion properties of highly and poorly metastatic HT-29 colon carcinoma cells with extracellular matrix components: role of integrin expression and cytoskeletal components

“…Using other subclones of HT-29 cells, Danecker et al (1989) found similar differences in the adhesion behaviour of colorectal carcinoma cells, with poorly differentiated cell clones adhering better to FN. In contrast to other studies (Schreiner et al, 1991;Lehmann et al, 1994;Herzberg et al, 1996), we detected little or no adhesion of HT-29P cells to FN or VN under the conditions used for the adhesion assays. In previous studies with the HT-29LMM subclone, a higher rate of adhesion to liver endothelial cells was demonstrated compared to endothelial cells derived from lung (Sawada et al, 1996).…”

“…Previously it has been shown that the integrin expression of HT-29 cells was also independent from the state of differentiation of these cells (Schreiner et al, 1991). The moderate adhesion to LN was not mediated by the α 6 β 4 -integrin.…”

Integrins and human intestinal cell functions

“…The alpha6beta4 integrin was first reported as a laminin receptor in intestinal cells working in cooperation with another beta1 integrin, most likely alpha2beta1 (107,111,112). In hemidesmosome-expressing cells such as those at the epidermal-mesenchymal interface, alpha6beta4 plays an essential role in the assembly and for the stability of hemidesmosomes while it mediates anchorage on laminin-5 in cooperation with alpha3beta1 (113)(114)(115).…”

Inhibition of integrin α5β1 function with a small peptide (ATN‐161) plus continuous 5‐FU infusion reduces colorectal liver metastases and improves survival in mice

“…14 However, only a few human colon cancer cell lines are known to express this integrin. 14,16,17 Recently, Livant et al 15 demonstrated that a small peptide antagonist (amino-acid sequence PHSCN) to integrin ␣ 5 ␤ 1 significantly reduced neovascularization and formation of metastases in an animal model of prostate carcinoma that expresses integrin ␣ 5 ␤ 1 .…”