Nuclear E-cadherin and VHL immunoreactivity are prognostic indicators of clear-cell renal cell carcinoma

Abstract

The loss of functional von Hippel-Lindau (VHL) tumor suppressor gene is associated with the development of clear-cell renal cell carcinoma (CC-RCC). Recently, VHL was shown to promote the transcription of E-cadherin, an adhesion molecule whose expression is inversely correlated with the aggressive phenotype of numerous epithelial cancers. Here, we performed immunohistochemistry on CC-RCC tissue microarrays to determine the prognostic value of E-cadherin and VHL with respect to Fuhrman grade and clinical prognosis. Low Fuhrman grade and good prognosis associated with positive VHL and E-cadherin immunoreactivity, whereas poor prognosis and high-grade tumors associated with a lack of E-cadherin and lower frequency of VHL staining. A significant portion of CC-RCC with positive VHL immunostaining correlated with nuclear localization of C-terminally cleaved E-cadherin. DNA sequencing revealed in a majority of nuclear E-cadherin-positive CC-RCC, subtle point mutations, deletions and insertions in VHL. Furthermore, nuclear E-cadherin was not observed in chromophobe or papillary RCC, as well as matched normal kidney tissue. In addition, nuclear E-cadherin localization was recapitulated in CC-RCC xenografts devoid of functional VHL or reconstituted with synthetic mutant VHL grown in SCID mice. These findings provide the first evidence of aberrant nuclear localization of E-cadherin in CC-RCC harboring VHL mutations, and suggest potential prognostic value of VHL and E-cadherin in CC-RCC. [4][5][6][7] Currently, a prediction of patient survival is based on traditional clinical parameters, including tumor size and Fuhrman nuclear grade. 8 However, the emerging understanding of the molecular pathways implicated in CC-RCC genesis and progression is providing previously unappreciated markers, which may serve as additional or better prognostic indicators of CC-RCC.The principal cause of sporadic CC-RCC and familial von Hippel-Lindau (VHL) disease-associated CC-RCC is the inactivating mutations of VHL. Although VHL patients also develop tumors in other organs including the central nervous system, retina and the adrenal gland, CC-RCC remains to be the leading cause of morbidity and death for VHL patients. 9 The most well-established function of VHL is its role in the oxygen-dependent negative regulation of hypoxia-inducible factor (HIF). VHL is a substrate-conferring component of an E3 ubiquitin ligase ECV (elongins/Cul2/VHL) that polyubiquitylates the catalytic a-subunit of HIF that has undergone hydroxylation on conserved prolyl residues within the oxygen-dependent degradation (ODD) domain. Prolyl hydroxylation is mediated by a class of prolyl hydroxylases (PHD1-3) in an oxygen-dependent manner. Thus, under hypoxia or in the absence of a functional VHL, HIFa becomes stabilized and binds to its common and constitutively expressed b-subunit, forming an active HIF transcription factor capable of transactivating numerous hypoxia-inducible genes such as vascular endothelial growth factor (VEGF),

The VHL-HIF Signaling in Renal Cell Carcinoma: Promises and Pitfalls

“…Further reports of E-cadherin loss in pre-malignant foci of VHL patients has led to the suggestion that E-cadherin loss is an early step in the pathogenesis of RCC, attributed to VHL inactivation (Esteban et al, 2006;Russell&Ohh, 2007). In line with these observations, tissue microarray of human RCC samples has shown the lack of E-cadherin immunoreactivity in VHL-deficient samples (Gervais et al, 2007). This study also found that low Fuhrman grade samples were positive for E-cadherin and VHL immunostaining and had a better prognosis.…”

“…EMT is the hallmark of many cancers, in which E-cadherin-mediated cell-cell adherence is lost and the cells attain hyper-proliferative, invasive and metastatic properties (Behrens et al, 1989;Thiery, 2002;Krishnamachary et al, 2006). While the reasons for loss of E-cadherin in cancers are undoubtedly multifactoral, many studies have shown a direct role of VHL in regulating E-cadherin expression in RCC (Esteban et al, 2006;Krishnamachary et al, 2006;Evans et al, 2007;Russell&Ohh, 2007).…”

Positive regulation of spondin 2 by thyroid hormone is associated with cell migration and invasion

“…4C). The expression of the adhesion molecule E-cadherin is inversely correlated with the aggressive phenotype of numerous epithelial cancers (Gervais et al 2007), whereas fibronectin (FN) serves as a general cell adhesion molecule by anchoring cells to collagen or proteoglycan substrates (Potts & Campbell 1994). The expression of these two proteins was reduced in the two shSP2 cells compared with the control cells (shEGFP; Fig.…”

NF-κB–Dependent Plasticity of the Epithelial to Mesenchymal Transition Induced by Von Hippel-Lindau Inactivation in Renal Cell Carcinomas

“…A connection between biallelic inactivation of VHL and suppression of E-cadherin expression has been previously reported in both preclinical models and patient specimens, and HIFα has been indicted as mediating this phenomenon through induction of Twist, Slug, Snail, Zeb1, and Zeb2 depending on the cellular context (23)(24)(25)27). However, the molecular underpinnings of HIFα-induced upregulation of these EMT-inducing transcription factors have been largely undefined, although evidence in support of the ability of HIF1α to directly induce Twist transcription through binding to a hypoxia response element within the Twist proximal promoter has been recently described in human embryonic kidney cells (28).…”