Loss of intercellular adhesion activates a transition from low‐ to high‐grade human squamous cell carcinoma

Abstract

The relationship between loss of intercellular adhesion and the biologic properties of human squamous cell carcinoma is not well understood. We investigated how abrogation of E-cadherin-mediated adhesion influenced the behavior and phenotype of squamous cell carcinoma in 3D human tissues. Cell-cell adhesion was disrupted in early-stage epithelial tumor cells (HaCaT-II-4) through expression of a dominant-negative form of E-cadherin (H-2K dEcad). Three-dimensional human tissue constructs harboring either H-2K d -Ecad-expressing or control II-4 cells (pBabe, H-2K dEcadDC25) were cultured at an air-liquid interface for 8 days and transplanted to nude mice; tumor phenotype was analyzed 2 days and 2 and 4 weeks later. H-2Kd -Ecad-expressing tumors demonstrated a switch to a high-grade aggressive tumor phenotype characterized by poorly differentiated tumor cells that infiltrated throughout the stroma. This high-grade carcinoma revealed elevated cell proliferation in a random pattern, loss of keratin 1 and diffuse deposition of laminin 5 c2 chain. When II-4 cell variants were seeded into type I collagen gels as an in vitro assay for cell migration, we found that only E-cadherin-deficient cells detached, migrated as single cells and expressed N-cadherin. Functionblocking studies demonstrated that this migration was matrix metalloproteinase-dependent, as GM-6001 and TIMP-2, but not TIMP-1, could block migration. Gene expression profiles revealed that E-cadherin-deficient II-4 cells demonstrated increased expression of proteases and cell-cell and cell-matrix proteins. These findings showed that loss of E-cadherin-mediated adhesion plays a causal role in the transition from low-to high-grade squamous cell carcinomas and that the absence of E-cadherin is an important prognostic marker in the progression of this disease. ' 2005 Wiley-Liss, Inc.Key words: E-cadherin; squamous cell carcinoma; matrix metalloproteinase; laminin 5; tumor microenvironment E-cadherin is known to be a tumor suppressor gene since the loss of E-cadherin function in tumor progression during the advanced stages of carcinoma progression is well established [1][2][3] and has been linked to a poor clinical prognosis in vivo.4-6 Studies using 2D monolayer cultures have demonstrated the direct influence of E-cadherin function on the malignant properties of transformed cells at an advanced stage. For example, abrogation of E-cadherin-mediated adhesion 7-10 induced tumor cell invasion in vitro while restoration of E-cadherin function resulted in growth retardation and inhibition of invasive properties.3,9 However, the role that loss of E-cadherin-mediated adhesion may play in early stages of carcinoma progression is poorly understood, as studies have demonstrated either a reduction 11,12 or an increase 13,14 of E-cadherin function during the initial stages of epithelial cancer progression.Further elucidation of the impact of altered cell-cell adhesion on early events in squamous cell carcinoma progression has been limited by the inability of monolayer culture t...

Sequential Down-regulation of E-Cadherin with Squamous Cell Carcinoma Progression: Loss of E-Cadherin via a Prostaglandin E2-EP2–Dependent Posttranslational Mechanism

“…Loss of E-cadherin has been correlated in clinical studies with various pathologic and clinical features, such as tumor dedifferentiation, infiltrative growth, and a poorer patient prognosis (37,38). In addition, UVR, a potent skin cancer inducer, has been shown to down-regulate E-cadherin expression in human tissue skin constructs in vitro; similar results have also been shown in human malignant skin lesions, suggesting that E-cadherin down-regulation plays a critical role in SCC progression (7)(8)(9).…”

“…Moreover, several groups have shown that defective E-cadherin function can render noninvasive cells invasive, whereas reestablishing functional E-cadherin complexes in tumorigenic cell lines reverts an invasive mesenchymal phenotype to a benign epithelial phenotype (4)(5)(6). In skin, in vitro work and studies using human malignant skin lesions suggest that decreased E-cadherin function plays a critical role in SCC progression (7)(8)(9)(10). However, exposure to chronic UV irradiation (UVR) remains the largest risk factor associated with the development of SCCs, and these prior studies did not determine the mechanism(s) by which E-cadherin expression is temporally regulated by acute or chronic doses of UVR in vivo.…”

E-cadherin loss promotes the initiation of squamous cell carcinoma invasion through modulation of integrin-mediated adhesion

“…However, in early-stage tumor cells such as II-4, it is thought that mutation of the Ha-Ras gene may be more directly related to growth-regulatory pathways (Delhedde, 1999) rather than altering cell adhesion. As recently shown, E-cadherin-deficient-II-4 cells do not show all features of EMT (Margulis et al, 2005a), suggesting that the combinatorial effect of Ha-Ras activation, p53 loss and Ecadherin suppression are insufficient to fully induce EMT in these early-stage tumor cells.…”

“…Epidermal reconstructs were established in vitro with either control II-4 cells expressing pBabe or H-2k d -EcadC25 or with II-4 cells expressing a dominant-interfering E-cadherin (H2k d -Ecad). The H-2k d -Ecad transgene has previously been described to interfere with E-cadherin function in normal keratinocytes (Zhu and Watt, 1996) and II-4 cells (Margulis et al 2005a). This occurs as overexpression of this fusion protein leads to destabilization of endogenous E-cadherin-␤-catenin complexes upon the cytoplasmic sequestration of ␤-catenin by the dominant-interfering transgene and to loss of E-cadherinmediated intercellular adhesion.…”

Frequent accumulation of nuclear E-cadherin and alterations in the Wnt signaling pathway in esophageal squamous cell carcinomas

“…22,23 Previous studies showed that decreased immunoreactivity of E-cadherin statistically correlated with the presence of lymph node metastases in esophageal squamous cell carcinoma, and loss of intercellular adhesion activates a transition from low-to high-grade squamous cell carcinoma, thus indicating an important role for E-cadherin as a prognostic marker in the progression of tumors. 24,25 Increased expression of the 80 kDa fragment of E-cadherin in metastatic prostate cancer in association with increased levels of several metalloproteinases, which are believed to be responsible for cleavage of short E-cadherin fragment from the full-length Ecadherin, are suggested to induce tumor progression in this tumor. 26 Metalloproteinases differentially expressed by tumor and stromal cells are finely regulated by interaction with distinct cellular and extracellular components of the tumor environment.…”