Characterization of gene expression and activated signaling pathways in solid-pseudopapillary neoplasm of pancreas

Mod Pathol. 2014 Apr;27(4):580-93. doi: 10.1038/modpathol.2013.154. Epub 2013 Sep 27.

Abstract

Solid-pseudopapillary neoplasm is an uncommon pancreatic tumor with distinct clinicopathologic features. Solid-pseudopapillary neoplasms are characterized by mutations in exon 3 of CTNNB1. However, little is known about the gene and microRNA expression profiles of solid-pseudopapillary neoplasms. Thus, we sought to characterize solid-pseudopapillary neoplasm-specific gene expression and identify the signaling pathways activated in these tumors. Comparisons of gene expression in solid-pseudopapillary neoplasm to pancreatic ductal carcinomas, neuroendocrine tumors, and non-neoplastic pancreatic tissues identified solid-pseudopapillary neoplasm-specific mRNA and microRNA profiles. By analyzing 1686 (1119 upregulated and 567 downregulated) genes differentially expressed in solid-pseudopapillary neoplasm, we found that the Wnt/β-catenin, Hedgehog, and androgen receptor signaling pathways, as well as genes involved in epithelial mesenchymal transition, are activated in solid-pseudopapillary neoplasms. We validated these results experimentally by assessing the expression of β-catenin, WIF-1, GLI2, androgen receptor, and epithelial-mesenchymal transition-related markers with western blotting and immunohistochemistry. Our analysis also revealed 17 microRNAs, especially the miR-200 family and miR-192/215, closely associated with the upregulated genes associated with the three pathways activated in solid-pseudopapillary neoplasm and epithelial mesenchymal transition. Our results provide insight into the molecular mechanisms underlying solid-pseudopapillary neoplasm tumorigenesis and its characteristic less epithelial cell differentiation than the other common pancreatic tumors.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers, Tumor / analysis
  • Biomarkers, Tumor / genetics*
  • Cell Transformation, Neoplastic / genetics
  • Cluster Analysis
  • Epithelial-Mesenchymal Transition / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic*
  • Gene Regulatory Networks
  • Hedgehog Proteins / genetics
  • Humans
  • MicroRNAs / analysis
  • Pancreatic Neoplasms / chemistry
  • Pancreatic Neoplasms / genetics*
  • Pancreatic Neoplasms / pathology
  • RNA, Messenger / analysis
  • Receptors, Androgen / genetics
  • Reproducibility of Results
  • Retrospective Studies
  • Signal Transduction / genetics*
  • Wnt Signaling Pathway / genetics

Substances

  • AR protein, human
  • Biomarkers, Tumor
  • Hedgehog Proteins
  • MicroRNAs
  • RNA, Messenger
  • Receptors, Androgen