Reduced expression of plakoglobin correlates with adverse outcome in patients with neuroblastoma

Tel Aviv University, Tell Afif, Tel Aviv, Israel
American Journal Of Pathology (Impact Factor: 4.6). 08/2001; 159(1):43-9. DOI: 10.1016/S0002-9440(10)61671-9
Source: PubMed

ABSTRACT Plakoglobin and its homologue beta-catenin are cytoplasmic proteins that mediate adhesive functions by interacting with cadherin receptors and signaling activities by interacting with transcription factors. It has been suggested that plakoglobin can suppress tumorigenicity whereas beta-catenin can act as an oncogene. We investigated the correlation between the expression pattern of N-cadherin, beta-catenin, and plakoglobin and tumor behavior in primary tumors of 20 neuroblastoma patients of all stages and in 11 human neuroblastoma cell lines. N-cadherin and beta-catenin were detected in 9 of 11 and 11 of 11 cell lines, respectively, whereas plakoglobin was undetectable or severely reduced in 6 of 11 cell lines. Tumor cells from 16 of 20 patients expressed N-cadherin and 20 of 20 patients expressed beta-catenin at levels similar to those of normal ganglion cells. Plakoglobin was undetectable in 9 of 20 tumors. Plakoglobin deficiency in the primary tumors was significantly associated with adverse clinical outcome. Five of the patients with plakoglobin-negative tumors died whereas four patients are alive without evident disease. In contrast, all patients with plakoglobin-positive tumors are alive; 2 of 11 are alive with the disease and 9 of 11 are alive without evident disease. These results suggest that down-regulation of plakoglobin may be of prognostic value for neuroblastoma patients as predictor of poor outcome.

  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: One of the first and most important steps in the metastatic cascade is the loss of cell-cell and cell-matrix interactions. N-cadherin, a crucial mediator of homotypic and heterotypic cell-cell interactions, might play a central role in the metastasis of neuroblastoma (NB), a solid tumor of neuroectodermal origin. Using Reverse Transcription Quantitative PCR (RT-qPCR), Western blot, immunocytochemistry and Tissue MicroArrays (TMA) we demonstrate the expression of N-cadherin in neuroblastoma tumors and cell lines. All neuroblastic tumors (n = 356) and cell lines (n = 10) expressed various levels of the adhesion protein. The N-cadherin mRNA expression was significantly lower in tumor samples from patients suffering metastatic disease. Treatment of NB cell lines with the N-cadherin blocking peptide ADH-1 (Exherin, Adherex Technologies Inc.), strongly inhibited tumor cell proliferation in vitro by inducing apoptosis. Our results suggest that N-cadherin signaling may play a role in neuroblastoma disease, marking involvement of metastasis and determining neuroblastoma cell viability.
    PLoS ONE 02/2012; 7(2):e31206. DOI:10.1371/journal.pone.0031206 · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: It is well known that sonic hedgehog signaling pathway plays a vital role during early embryonic development. It is also responsible for stem cell renewal and development of several cancers like colorectal and breast carcinoma and major brain tumors as medulloblastoma and glioblastoma. The role of sonic hedgehog signaling in the development of neuroblastoma has not been thoroughly investigated. In this study, we attempted to determine the expression of Bmi-1 stem cell marker and of Shh pathway downstream target genes glioma-associated oncogene homolog 1 (GLI1), protein patched homolog 1 (PTCH1), Cyclin D2, plakoglobin (γ catenin), NK2 homeobox 2 (NKX2.2), paired box gene 6 (PAX6), secreted frizzled-related protein 1 (SFRP1), and hedgehog interacting protein (HHIP) in 11 neuroblastoma cell lines and 41 neuroblastoma samples. Also, inhibition of the pathway was performed genetically by GLI1 knockdown siRNA or chemically by cyclopamine. After inhibition, low transcript expression was detected in downstream target genes like PTCH1, in the cell lines. We further preformed promoter methylation studies of Cyclin D2, PTCH1, HHIP, and SFRP1 genes by melting curve analysis-based methylation assay (MCA-Meth) and methylation-specific PCR (MSP). Results revealed no methylation in Cyclin D2 gene promoter in neuroblastoma samples or in cell lines; one cell line (MHH-NB-11) showed PTCH1 methylation; 3/11 (27%) cell lines and 9/41 (22%) neuroblastoma samples showed HHIP methylation; and 3/11 (27%) cell lines and 11/41 (27%) samples showed SFRP1 methylation. Taken together, our results suggest the possibility of two levels of control of the sonic hedgehog signaling pathway: transcriptional and epigenetic, which might offer new therapeutic possibilities to modulate the pathway and try to suppress tumor growth.
    Tumor Biology 02/2011; 32(1):113-27. DOI:10.1007/s13277-010-0105-x · 2.84 Impact Factor

Full-text (2 Sources)

Available from
May 16, 2014