Expression of APO‐1 (CD95), a member of the NGF/TNF receptor superfamily, in normal and neoplastic colon epithelium

Abstract

APO-1 is a 48-kDa cell-membrane protein identical to the Fas antigen now designated CD95. It is a member of the NGF/TNF receptor superfamily. Anti-APO-1 monoclonal antibody induces apoptosis in a variety of cell types expressing this antigen. We immunohistochemically investigated APO-1 expression in normal colon mucosa, 20 adenomas, 258 colon carcinomas and 10 liver metastases and carried out in vitro studies using a panel of colon-carcinoma cell lines. Immunohistochemically, APO-1 was regularly expressed at the basolateral membrane of normal colon epithelia. In a minor fraction of colon adenomas and in 39.1% of colon carcinomas APO-1 expression was diminished and in 48.1% of carcinomas, predominantly of the non-mucinous type, APO-1 expression was completely abrogated. The normal level of APO-1 in carcinomas was correlated with the mucinous type. Reduced/lost APO-1 expression was more frequent in rectal carcinomas. Complete loss of APO-1 was more frequent in tumors that had already metastasized. APO-1 expression in liver metastases essentially corresponded to that of the primary tumors. Comparative analysis with data from previous studies revealed that the mode of APO-1 expression is correlated with that of HLA-A,B,C./beta 2m, HLA-DR, HLA-D-associated invariant chain and of the secretory component. Surface expression of APO-1 was heterogeneous in colon-carcinoma cell lines; SW480 expressed considerable amounts of APO-1 on all cells, while HT-29 constitutively did less so and only in a minority of cells. Surface density of APO-1 and the fraction of positive cells in HT-29 was enhanced by interferon-gamma (IFN-gamma) and, additively, by tumor necrosis factor-alpha (TNF-alpha), whereas in SW480 APO-1 expression was not modulated by these cytokines. We conclude that neoplastic transformation of colon epithelium often leads to a loss of the physiologic, high level of surface APO-1 by giving rise either to a stable lack of APO-1 or to an IFN-gamma/TNF-alpha-sensitive phenotype of inducible APO-1 expression.

Endothelin-receptor antagonists are proapoptotic and antiproliferative in human colon cancer cells

“…Bosentan alone dose-dependently increased apoptosis in SW480 cells, while it had little effect on HT29 cells (Figure 4, open symbols). In the presence of FasL, HT29 cells were partially resistant to FasL-mediated apoptosis after 24 h of treatment, while SW480 cells were sensitive to FasL-induced apoptosis (Figure 4, closed symbols), confirming previous information for SW480 cells (Möller et al, 1994 Two ET-receptor antagonists structurally unrelated to bosentan, BQ123 (ET A -specific) and BQ788 (ET B -specific), were investigated. Both BQ123 or BQ788 (at 80 mM concentrations) alone or in combination significantly ( Figure 4C; Po0.0004 for all treatments vs control), but not synergistically, sensitised HT29 cells to FasLmediated apoptosis like bosentan.…”

Down-regulation of Fas gene expression in colon cancer is not a result of allelic loss or gene rearrangement

“…Fas protein is expressed in variable levels on the surface of several colon cancer cell lines. In some cell lines, low expression of Fas may be up-regulated by the cytokines TNF-a or interferon gamma (IFN-y) to levels similar to that of activated T cells (Yonehara et al, 1989;Itoh et al, 1991;Moller et al, 1994 (Yonehara et al, 1989;Abreu-Martin et al, 1995), while growth of KM12C cells is inhibited by the anti-Fas antibody (Owen-Schaub et al, 1993, 1994. Metastatic variants of KM12C cells are more resistant to the effects of the antibody, despite a similar level of Fas expression (Owen-Schaub et al, 1994).…”

“…Fas signalling has also been linked to apoptosis outside the lymphoid population, including the regression of ovarian follicles after ovulation and maintenance of cellular homeostasis in the liver (Adachi et al, 1995;Hakuno et al, 1996). The epithelial layer of the normal colonic mucosa expresses Fas protein at high levels, from the bottoms of the crypts to the luminal surface (Leithauser et al, 1993;Moller et al, 1994). A functional role for Fas receptors in the colon has not yet been demonstrated, as the Fas ligand has not been detected in the colon, except in subsets of lymphocytes in the lamina propria .…”

“…A functional role for Fas receptors in the colon has not yet been demonstrated, as the Fas ligand has not been detected in the colon, except in subsets of lymphocytes in the lamina propria . Expression of Fas protein in the colon is progressively reduced during the transformation of normal epithelium to benign neoplasms, adenocarcinomas and, ultimately, to metastases (Leithauser et al, 1993;Moller et al, 1994). Moller and co-workers (1994) reported that the extent of loss was related to the stage of the disease, as only 10% of adenomas exhibited reduced Fas expression compared with 88% of carcinomas.…”

In vitro and in vivo delivery of novel anticancer fusion protein MULT1E/FasTI via adenoviral vectors

“…11,12 One of the strategies that tumor cells have developed to escape NKG2D-mediated cytolysis by NK cells or cells expressing NKG2D is down-regulating NKG2D ligands such as MICA, 13,14 a process also called shedding. Tumor cells also escape Fas-mediated apoptosis by decreasing surface expression of Fas, 15,16 secreting an antagonistic 'decoy' receptor, 17 expressing anti-apoptotic molecules such as BCL2 family members, 17,18 down-regulating and mutating pro-apoptotic genes such as BAX, APAF1 or Fas. [19][20][21][22][23] In our earlier study 24 we combined the function of NKG2D-mediated cytolysis and Fas-mediated apoptosis into one functional fusion protein by using the extracellular domain of MULT1 and the transmembrane and intracellular domains of Fas in a mouse model.…”