Epithelial mesenchymal transition is required for acquisition of anoikis resistance and metastatic potential in adenoid cystic carcinoma

PLoS One. 2012;7(12):e51549. doi: 10.1371/journal.pone.0051549. Epub 2012 Dec 14.

Abstract

Human adenoid cystic carcinoma (ACC) is characterized by diffused invasion of the tumor into adjacent organs and early distant metastasis. Anoikis resistance and epithelial mesenchymal transition (EMT) are considered prerequisites for cancer cells to metastasize. Exploring the relationship between these processes and their underlying mechanism of action is a promising way to better understand ACC tumors. We initially established anoikis-resistant sublines of ACC cells; the variant cells revealed a mesenchymal phenotype through Slug-mediated EMT-like transformation and displayed enhanced metastatic potential both in vitro and in vivo. Suppression of EMT by knockdown of Slug significantly impaired anoikis resistance, migration, and invasion of the variant cells. With overexpression of Slug and Twist, we determined that induction of EMT in normal ACC cells could prevent anoikis, albeit partially. These findings strongly suggest that EMT is indispensable in anoikis resistance, at least in ACC cells. Furthermore, we found that the EGFR/PI3K/Akt pathway acts as the common regulator for EMT-like transformation and anoikis resistance, as confirmed by their specific inhibitors. Gefitinib and LY294003 restored the sensibilities of anoikis-resistant cells to anoikis and simultaneously impaired their metastatic potential. In addition, the results from our in vivo model of metastasis suggest that pretreatment with gefitinib promotes mouse survival by alleviating pulmonary metastasis. Most importantly, immunohistochemistry of human ACC specimens showed a correlation between the overexpression of Slug and EGFR staining. This study has demonstrated that Slug-mediated EMT-like transformation is required by human ACC cells to achieve anoikis resistance and their metastatic potential. Targeting the EGFR/PI3K/Akt pathway holds potential as a preventive strategy against distant metastasis of ACC.

Publication types

  • Research Support, Non-U.S. Gov't
  • Retracted Publication

MeSH terms

  • Animals
  • Anoikis*
  • Antineoplastic Agents / pharmacology*
  • Apoptosis
  • Carcinoma, Adenoid Cystic / metabolism*
  • Carcinoma, Adenoid Cystic / pathology*
  • Cell Line, Tumor
  • Cell Movement
  • Epithelial-Mesenchymal Transition*
  • ErbB Receptors / metabolism
  • Female
  • Gefitinib
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Lung Neoplasms / secondary
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • Neoplasm Transplantation
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Quinazolines / pharmacology
  • Salivary Gland Neoplasms / metabolism*
  • Salivary Gland Neoplasms / pathology*
  • Snail Family Transcription Factors
  • Transcription Factors / metabolism

Substances

  • Antineoplastic Agents
  • Quinazolines
  • SNAI1 protein, human
  • Snai2 protein, mouse
  • Snail Family Transcription Factors
  • Transcription Factors
  • Phosphatidylinositol 3-Kinases
  • ErbB Receptors
  • Proto-Oncogene Proteins c-akt
  • Gefitinib

Grants and funding

This work was supported by the grants from The National Natural Science Foundation of China (81102054, 30973330, 81170977). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.