Characterization of ascites-derived ovarian tumor cells from spontaneously occurring ovarian tumors of the chicken: evidence for E-cadherin upregulation

PLoS One. 2013;8(2):e57582. doi: 10.1371/journal.pone.0057582. Epub 2013 Feb 27.

Abstract

Ovarian cancer, a highly metastatic disease, is the fifth leading cause of cancer-related deaths in women. Chickens are widely used as a model for human ovarian cancer as they spontaneously develop epithelial ovarian tumors similar to humans. The cellular and molecular biology of chicken ovarian cancer (COVCAR) cells, however, have not been studied. Our objectives were to culture COVCAR cells and to characterize their invasiveness and expression of genes and proteins associated with ovarian cancer. COVCAR cell lines (n = 13) were successfully maintained in culture for up to19 passages, cryopreserved and found to be viable upon thawing and replating. E-cadherin, cytokeratin and α-smooth muscle actin were localized in COVCAR cells by immunostaining. COVCAR cells were found to be invasive in extracellular matrix and exhibited anchorage-independent growth forming colonies, acini and tube-like structures in soft agar. Using RT-PCR, COVCAR cells were found to express E-cadherin, N-cadherin, cytokeratin, vimentin, mesothelin, EpCAM, steroidogenic enzymes/proteins, inhibin subunits-α, βA, βB, anti-müllerian hormone, estrogen receptor [ER]-α, ER-β, progesterone receptor, androgen receptor, and activin receptors. Quantitative PCR analysis revealed greater N-cadherin, vimentin, and VEGF mRNA levels and lesser cytokeratin mRNA levels in COVCAR cells as compared with normal ovarian surface epithelial (NOSE) cells, which was suggestive of epithelial-mesenchymal transformation. Western blotting analyses revealed significantly greater E-cadherin levels in COVCAR cell lines compared with NOSE cells. Furthermore, cancerous ovaries and COVCAR cell lines expressed higher levels of an E-cadherin cleavage product when compared to normal ovaries and NOSE cells, respectively. Cancerous ovaries were found to express significantly higher ovalbumin levels whereas COVCAR cell lines did not express ovalbumin thus suggesting that the latter did not originate from oviduct. Taken together, COVCAR cell lines are likely to improve our understanding of the cellular and molecular biology of ovarian tumors and its metastasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ascites / pathology*
  • Avian Proteins / genetics
  • Avian Proteins / metabolism
  • Cadherins / genetics*
  • Cadherins / metabolism
  • Cell Adhesion
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Chickens
  • Epithelial Cells / pathology
  • Extracellular Matrix / metabolism
  • Female
  • Gene Expression Regulation, Neoplastic
  • Hormones / biosynthesis
  • Humans
  • Immunohistochemistry
  • Neoplasm Invasiveness
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism
  • Neoplasm Staging
  • Ovarian Neoplasms / genetics
  • Ovarian Neoplasms / pathology*
  • Ovary / metabolism
  • Ovary / pathology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Signal Transduction / genetics
  • Up-Regulation / genetics*
  • Wound Healing

Substances

  • Avian Proteins
  • Cadherins
  • Hormones
  • Neoplasm Proteins
  • RNA, Messenger

Grants and funding

The authors acknowledge funding support from the College of Agricultural Sciences, Pennsylvania State University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.