Original Paper
Immunohistological analysis of E-cadherin, α-, β- and γ-catenin expression in colorectal cancer: implications for cell adhesion and signaling

https://doi.org/10.1016/S0959-8049(98)00344-XGet rights and content

Abstract

Intercellular adhesion mediated by the E-cadherin/catenin complex is a prerequisite for epithelial integrity and differentiation. In carcinomas, E-cadherin function is frequently disturbed, and has been suggested to increase invasion and metastasis of tumour cells. β-catenin has also been implicated in signaling pathways essential for tumour formation. We analysed the E-cadherin/catenin adhesion system of colorectal tumours at different clinical stages. In primary carcinomas (n=91), there was a frequent reduction in E-cadherin (44%) and α-catenin expression (36%). In contrast, β-catenin and γ-catenin expression were seldom reduced (4% and 15%, respectively). Similar expression patterns were observed in liver metastases from unrelated colorectal tumours (n=27). There was a significant relationship between loss of E-cadherin and α-catenin expression and poorly differentiated (G3–4) tumours. Our results suggest that reduction of E-cadherin/α-catenin expression is a frequent event in primary and metastatic colorectal carcinomas. Furthermore, β-catenin expression remains normal in colorectal cancer, suggesting the essential role of β-catenin in signaling pathways

Introduction

The prognosis of colorectal cancer patients is determined by the development of metastases. The metastatic cascade starts with a breakdown of the epithelial integrity which enables tumour cells to leave epithelial structures, to invade the surrounding stroma, to enter either blood or lymphatic vessels and extravasate in the appropriate target organs.

Epithelial differentiation is critically dependent on the proper formation of intercellular junctions by cell–cell adhesion molecules. Impairment of the junctions allows invasion of epithelial cells and the progression of carcinomas[1]. Among the cell–cell adhesion molecules, E-cadherin is located at the zonula adherens and is a functional necessity for the integrity of epithelia2, 3. Cadherins are calcium-dependent transmembrane adhesion molecules which connect cells homotypically. In vitro studies in tumour cell lines have shown that disturbance of E-cadherin function is correlated with the acquisition of invasive properties4, 5, 6. Furthermore, decreased levels of E-cadherin expression have been noted in many immunohistochemical studies of epithelial cancers7, 8, 9, 10, 11, 12. In some tumour types, including colorectal cancer, the loss of E-cadherin expression has been associated with loss of differentiated features in the tumour and has been found to correlate with an increased likelihood of distant metastases, suggesting a potential role for E-cadherin as an invasion or metastasis suppressor8, 13. Additionally, mutations of the E-cadherin gene have been described in gastric and breast cancer. These mutations lead to exon skipping with a diminished function of the calcium-binding regions[14]or to truncated fragments which are expected to be secreted[15]. In both cases the cell-adhesion activity of E-cadherin will be impaired.

The cytoplasmic domain of E-cadherin interacts with intracellular proteins called α-, β- and γ-catenins, which make contact with the microfilament network2, 3. The interaction of these molecules is the prerequisite for the proper formation of functionally intact adherens junctions. α-Catenin shows sequence similarity to vinculin and interacts with the cytoskeleton16, 17, 18. β-Catenin is the vertebrate homologue of the segment polarity gene armadillo of Drosophila and makes direct contact with the cytoplasmic domain of E-cadherin19, 20. γ-Catenin (plakoglobin) is closely related to β-catenin and is also found in desmosomal junctions21, 22, 23. Catenins are essential for E-cadherin function, and alterations in expression or structure of the catenins may lead to the disassembly of adherens junctions and the generation of more invasive cells. In some human cancers, such as that of the breast, oesophagus and prostate, decreased expression of α-catenin has been noted24, 25, 26. In some tumours, genetic alterations including homozygous deletions or localised mutations of the α-catenin gene account for the decrease of α-catenin expression. In addition, alterations in β- and γ-catenin expression and phosphorylation have been described for some tumour cell lines27, 28, 29.

Besides their function in the adherens junctions, β-catenin and plakoglobin form complexes with the tumour-suppressor protein APC which are independent from the cadherin/catenin complex30, 31, 32. The APC gene is often mutated in colorectal cancer tissue. In familial adenomatosis coli (FAP) patients, APC is also altered as a germline mutation. In cells containing a mutated APC, intracellular β-catenin levels are elevated and can be reduced by reintroduction of wildtype APC[33]. Recently, it has been shown that β-catenin is frequently upregulated in adenomas and carcinomas of FAP patients, and a proportion of the protein is found in the cell nucleus[34].

β-Catenin has recently been shown to function as a transcription activator when complexed with members of the Tcf/LEF family of transcription factors35, 36. Additionally, it has been demonstrated that β-catenin forms permanent complexes with Tcf/LEF factors in colorectal cancer cell lines. Upregulation of β-catenin can occur as a result of mutations of APC (as indicated above) or mutations of β-catenin which prevent its downregulation37, 38.

In vitro and in vivo data thus suggest a pivotal role of cadherins and catenins in various aspects of tumour progression. In this study we analysed by immunohistochemistry the expression of E-cadherin and α-, β- and γ-catenins in different clinical stages of colorectal tumours.

Section snippets

Patients and methods

Snap-frozen colorectal carcinoma tissue from patients who had undergone colectomy or liver resection in our department was used in this study. The resected metastases were not related to the primary tumours in this study. A portion of the tissue was used for routine histopathological examination by the pathologist. Serial sections of 5 μm were cut in a Cryocut 300 microtome (Leica Instruments, Nussloch, Germany), and immunohistochemically stained with the anti-E-cadherin monoclonal antibody 6F9

Expression of E-cadherin, α-, β- and γ-catenin in primary colorectal carcinomas

Expression of E-cadherin, α-, β- and γ-catenin was clearly evident at the cell-cell boundaries of epithelial cells in normal colorectal mucosa (Fig. 1). Mesenchymal tissue surrounding the epithelial cells did not express E-cadherin or any of the catenins. In the colorectal carcinomas (n=91), various staining patterns were observed; i.e. tumours with normal (Fig. 2a), heterogenous (Fig. 2b) and absent (Fig. 2c) expression were found. E-cadherin and all three catenins were expressed in a similar

Discussion

In the present study, we examined the expression of E-cadherin and its intracellular binding partners α-, β- and γ-catenins in primary colorectal carcinomas, and found that expression of E-cadherin and α-catenin was frequently reduced, whereas β- and γ-catenin expression remained normal. Similar results were obtained in colorectal liver metastases. There was a significant relationship between reduced E-cadherin/α-catenin and lower tumour grade.

Various studies have shown that tumour invasion and

Acknowledgements

The excellent technical assistance of I. Wendler and A. Schmidt was highly appreciated.

References (48)

  • J Behrens et al.

    Dissecting tumor cell invasion: epithelial cells acquire invasive properties after the loss of uvomorulin-mediated cell–cell adhesion

    J Cell Biol

    (1989)
  • U.H Frixen et al.

    E-cadherin-mediated cell–cell adhesion prevents invasiveness of human carcinoma cells

    J Cell Biol

    (1991)
  • Vleminck K, Vakaet L Jr, Mareel M, Fiers W, van Roy. Genetic manipulation of E-cadherin expression by epithelial tumor...
  • J.H Schipper et al.

    E-cadherin expression in squamous cell carcinomas of head and neck: inverse correlation with tumor dedifferentiation and lymph node metastasis

    Cancer Res

    (1991)
  • S Dorudi et al.

    E-cadherin expression in colorectal cancer. An immunocytochemical and in situ hybridization study

    Am J Pathol

    (1993)
  • B Mayer et al.

    E-cadherin expression in primary and metastatic gastric cancer: down-regulation correlates with cellular dedifferentiation and glandular disintegration

    Cancer Res

    (1993)
  • D.L Rimm et al.

    Reduced alpha-catenin and E-cadherin expression in breast cancer

    Lab Invest

    (1995)
  • Y Shimoyama et al.

    Expression of E- and P-cadherin in gastric carcinomas

    Cancer Res

    (1991)
  • R Umbas et al.

    Expression of the cellular adhesion molecule E-cadherin is reduced or absent in high-grade prostate cancer

    Cancer Res

    (1992)
  • P.P Bringuier et al.

    Decreased E-cadherin immunoreactivity correlates with poor survival in patients with bladder tumours

    Cancer Res

    (1993)
  • K.F Becker et al.

    E-cadherin gene mutations provide clues to diffuse type gastric carcinomas

    Cancer Res

    (1994)
  • G Berx et al.

    E-cadherin is inactivated in a majority of invasive human lobular breast cancers by truncation mutations throughout its extracellular domain

    Oncogene

    (1996)
  • M Ozawa et al.

    Molecular organization of the uvomorulin-catenin complex

    J Cell Biol

    (1992)
  • P.D McCrea et al.

    A homolog of the armadillo protein in Drosophila (plakoglobin) associated with E-cadherin

    Science

    (1991)
  • Cited by (76)

    • Prognostic Value of E-cadherin-, CD44-, and MSH2-associated Nomograms in Patients With Stage II and III Colorectal Cancer

      2017, Translational Oncology
      Citation Excerpt :

      Dorudi et al. reported that ECAD expression was significantly related to the stage and grade of the tumor, and showed that more aggressive cancers exhibited an obvious reduction in ECAD expression [12]. Ghadimi et al. revealed a close relationship between reduced ECAD expression and lower tumor grade, but they did not observe a clear correlation between the loss of ECAD expression and the depth of tumor invasion [36]. In a multivariate study involving 84 CRC cases, Roca et al. showed that ECAD expression was not related to pathologic parameters, such as tumor stage, tumor grade, or lymph node metastasis, but the loss of ECAD was found to be an independent adverse prognostic factor [37].

    • Comparative proteomic analysis for the insoluble fractions of colorectal cancer patients

      2012, Journal of Proteomics
      Citation Excerpt :

      JUP (also called γ-catenine), is the only known constituent common to submembranous plaques in both desmosomes and intermediate junctions, and forms distinct complexes with E-cadherins and α-cadherins [52]. Among primary tumors, JUP is expressed in only 14% of tumors with differentiation grade I or II [53]. However, recent studies have shown that JUP is over-expressed in advanced metastatic tumors [54], and that a very high proportion of independent liver tumors are positive for JUP (96%) [52].

    • Significance of dysadherin and E-cadherin expression in differentiated-type gastric carcinoma with submucosal invasion

      2011, Human Pathology
      Citation Excerpt :

      Reduced intercellular adhesiveness is considered indispensable for cancer invasion and metastasis [12]. Reduced expression of E-cadherin is correlated with dedifferentiation, invasiveness, and the metastatic activity of carcinoma cells in various organs [13-16]. Irreversible and reversible mechanisms for inactivating the cell-cell adhesion system of E-cadherin in cancers have been reported [17].

    View all citing articles on Scopus
    View full text